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gerrit-public.fairphone.software / fp2-dev / platform / external / clang / ef8225444452a1486bd721f3285301fe84643b00 / . / lib / Sema / SemaChecking.cpp
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//===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements extra semantic analysis beyond what is enforced
// by the C type system.
//
//===----------------------------------------------------------------------===//
#include "clang/Sema/SemaInternal.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/EvaluatedExprVisitor.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/StmtObjC.h"
#include "clang/Analysis/Analyses/FormatString.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Basic/TargetBuiltins.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/Lexer.h" // TODO: Extract static functions to fix layering.
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/Sema.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/ConvertUTF.h"
#include "llvm/Support/raw_ostream.h"
#include <limits>
using namespace clang;
using namespace sema;
SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL,
unsigned ByteNo) const {
return SL->getLocationOfByte(ByteNo, getSourceManager(), LangOpts,
Context.getTargetInfo());
}
/// Checks that a call expression's argument count is the desired number.
/// This is useful when doing custom type-checking. Returns true on error.
static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) {
unsigned argCount = call->getNumArgs();
if (argCount == desiredArgCount) return false;
if (argCount < desiredArgCount)
return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args)
<< 0 /*function call*/ << desiredArgCount << argCount
<< call->getSourceRange();
// Highlight all the excess arguments.
SourceRange range(call->getArg(desiredArgCount)->getLocStart(),
call->getArg(argCount - 1)->getLocEnd());
return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args)
<< 0 /*function call*/ << desiredArgCount << argCount
<< call->getArg(1)->getSourceRange();
}
/// Check that the first argument to __builtin_annotation is an integer
/// and the second argument is a non-wide string literal.
static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) {
if (checkArgCount(S, TheCall, 2))
return true;
// First argument should be an integer.
Expr *ValArg = TheCall->getArg(0);
QualType Ty = ValArg->getType();
if (!Ty->isIntegerType()) {
S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg)
<< ValArg->getSourceRange();
return true;
}
// Second argument should be a constant string.
Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts();
StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg);
if (!Literal || !Literal->isAscii()) {
S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg)
<< StrArg->getSourceRange();
return true;
}
TheCall->setType(Ty);
return false;
}
/// Check that the argument to __builtin_addressof is a glvalue, and set the
/// result type to the corresponding pointer type.
static bool SemaBuiltinAddressof(Sema &S, CallExpr *TheCall) {
if (checkArgCount(S, TheCall, 1))
return true;
ExprResult Arg(TheCall->getArg(0));
QualType ResultType = S.CheckAddressOfOperand(Arg, TheCall->getLocStart());
if (ResultType.isNull())
return true;
TheCall->setArg(0, Arg.get());
TheCall->setType(ResultType);
return false;
}
ExprResult
Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
ExprResult TheCallResult(TheCall);
// Find out if any arguments are required to be integer constant expressions.
unsigned ICEArguments = 0;
ASTContext::GetBuiltinTypeError Error;
Context.GetBuiltinType(BuiltinID, Error, &ICEArguments);
if (Error != ASTContext::GE_None)
ICEArguments = 0; // Don't diagnose previously diagnosed errors.
// If any arguments are required to be ICE's, check and diagnose.
for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) {
// Skip arguments not required to be ICE's.
if ((ICEArguments & (1 << ArgNo)) == 0) continue;
llvm::APSInt Result;
if (SemaBuiltinConstantArg(TheCall, ArgNo, Result))
return true;
ICEArguments &= ~(1 << ArgNo);
}
switch (BuiltinID) {
case Builtin::BI__builtin___CFStringMakeConstantString:
assert(TheCall->getNumArgs() == 1 &&
"Wrong # arguments to builtin CFStringMakeConstantString");
if (CheckObjCString(TheCall->getArg(0)))
return ExprError();
break;
case Builtin::BI__builtin_stdarg_start:
case Builtin::BI__builtin_va_start:
case Builtin::BI__va_start:
if (SemaBuiltinVAStart(TheCall))
return ExprError();
break;
case Builtin::BI__builtin_isgreater:
case Builtin::BI__builtin_isgreaterequal:
case Builtin::BI__builtin_isless:
case Builtin::BI__builtin_islessequal:
case Builtin::BI__builtin_islessgreater:
case Builtin::BI__builtin_isunordered:
if (SemaBuiltinUnorderedCompare(TheCall))
return ExprError();
break;
case Builtin::BI__builtin_fpclassify:
if (SemaBuiltinFPClassification(TheCall, 6))
return ExprError();
break;
case Builtin::BI__builtin_isfinite:
case Builtin::BI__builtin_isinf:
case Builtin::BI__builtin_isinf_sign:
case Builtin::BI__builtin_isnan:
case Builtin::BI__builtin_isnormal:
if (SemaBuiltinFPClassification(TheCall, 1))
return ExprError();
break;
case Builtin::BI__builtin_shufflevector:
return SemaBuiltinShuffleVector(TheCall);
// TheCall will be freed by the smart pointer here, but that's fine, since
// SemaBuiltinShuffleVector guts it, but then doesn't release it.
case Builtin::BI__builtin_prefetch:
if (SemaBuiltinPrefetch(TheCall))
return ExprError();
break;
case Builtin::BI__builtin_object_size:
if (SemaBuiltinConstantArgRange(TheCall, 1, 0, 3))
return ExprError();
break;
case Builtin::BI__builtin_longjmp:
if (SemaBuiltinLongjmp(TheCall))
return ExprError();
break;
case Builtin::BI__builtin_classify_type:
if (checkArgCount(*this, TheCall, 1)) return true;
TheCall->setType(Context.IntTy);
break;
case Builtin::BI__builtin_constant_p:
if (checkArgCount(*this, TheCall, 1)) return true;
TheCall->setType(Context.IntTy);
break;
case Builtin::BI__sync_fetch_and_add:
case Builtin::BI__sync_fetch_and_add_1:
case Builtin::BI__sync_fetch_and_add_2:
case Builtin::BI__sync_fetch_and_add_4:
case Builtin::BI__sync_fetch_and_add_8:
case Builtin::BI__sync_fetch_and_add_16:
case Builtin::BI__sync_fetch_and_sub:
case Builtin::BI__sync_fetch_and_sub_1:
case Builtin::BI__sync_fetch_and_sub_2:
case Builtin::BI__sync_fetch_and_sub_4:
case Builtin::BI__sync_fetch_and_sub_8:
case Builtin::BI__sync_fetch_and_sub_16:
case Builtin::BI__sync_fetch_and_or:
case Builtin::BI__sync_fetch_and_or_1:
case Builtin::BI__sync_fetch_and_or_2:
case Builtin::BI__sync_fetch_and_or_4:
case Builtin::BI__sync_fetch_and_or_8:
case Builtin::BI__sync_fetch_and_or_16:
case Builtin::BI__sync_fetch_and_and:
case Builtin::BI__sync_fetch_and_and_1:
case Builtin::BI__sync_fetch_and_and_2:
case Builtin::BI__sync_fetch_and_and_4:
case Builtin::BI__sync_fetch_and_and_8:
case Builtin::BI__sync_fetch_and_and_16:
case Builtin::BI__sync_fetch_and_xor:
case Builtin::BI__sync_fetch_and_xor_1:
case Builtin::BI__sync_fetch_and_xor_2:
case Builtin::BI__sync_fetch_and_xor_4:
case Builtin::BI__sync_fetch_and_xor_8:
case Builtin::BI__sync_fetch_and_xor_16:
case Builtin::BI__sync_add_and_fetch:
case Builtin::BI__sync_add_and_fetch_1:
case Builtin::BI__sync_add_and_fetch_2:
case Builtin::BI__sync_add_and_fetch_4:
case Builtin::BI__sync_add_and_fetch_8:
case Builtin::BI__sync_add_and_fetch_16:
case Builtin::BI__sync_sub_and_fetch:
case Builtin::BI__sync_sub_and_fetch_1:
case Builtin::BI__sync_sub_and_fetch_2:
case Builtin::BI__sync_sub_and_fetch_4:
case Builtin::BI__sync_sub_and_fetch_8:
case Builtin::BI__sync_sub_and_fetch_16:
case Builtin::BI__sync_and_and_fetch:
case Builtin::BI__sync_and_and_fetch_1:
case Builtin::BI__sync_and_and_fetch_2:
case Builtin::BI__sync_and_and_fetch_4:
case Builtin::BI__sync_and_and_fetch_8:
case Builtin::BI__sync_and_and_fetch_16:
case Builtin::BI__sync_or_and_fetch:
case Builtin::BI__sync_or_and_fetch_1:
case Builtin::BI__sync_or_and_fetch_2:
case Builtin::BI__sync_or_and_fetch_4:
case Builtin::BI__sync_or_and_fetch_8:
case Builtin::BI__sync_or_and_fetch_16:
case Builtin::BI__sync_xor_and_fetch:
case Builtin::BI__sync_xor_and_fetch_1:
case Builtin::BI__sync_xor_and_fetch_2:
case Builtin::BI__sync_xor_and_fetch_4:
case Builtin::BI__sync_xor_and_fetch_8:
case Builtin::BI__sync_xor_and_fetch_16:
case Builtin::BI__sync_val_compare_and_swap:
case Builtin::BI__sync_val_compare_and_swap_1:
case Builtin::BI__sync_val_compare_and_swap_2:
case Builtin::BI__sync_val_compare_and_swap_4:
case Builtin::BI__sync_val_compare_and_swap_8:
case Builtin::BI__sync_val_compare_and_swap_16:
case Builtin::BI__sync_bool_compare_and_swap:
case Builtin::BI__sync_bool_compare_and_swap_1:
case Builtin::BI__sync_bool_compare_and_swap_2:
case Builtin::BI__sync_bool_compare_and_swap_4:
case Builtin::BI__sync_bool_compare_and_swap_8:
case Builtin::BI__sync_bool_compare_and_swap_16:
case Builtin::BI__sync_lock_test_and_set:
case Builtin::BI__sync_lock_test_and_set_1:
case Builtin::BI__sync_lock_test_and_set_2:
case Builtin::BI__sync_lock_test_and_set_4:
case Builtin::BI__sync_lock_test_and_set_8:
case Builtin::BI__sync_lock_test_and_set_16:
case Builtin::BI__sync_lock_release:
case Builtin::BI__sync_lock_release_1:
case Builtin::BI__sync_lock_release_2:
case Builtin::BI__sync_lock_release_4:
case Builtin::BI__sync_lock_release_8:
case Builtin::BI__sync_lock_release_16:
case Builtin::BI__sync_swap:
case Builtin::BI__sync_swap_1:
case Builtin::BI__sync_swap_2:
case Builtin::BI__sync_swap_4:
case Builtin::BI__sync_swap_8:
case Builtin::BI__sync_swap_16:
return SemaBuiltinAtomicOverloaded(TheCallResult);
#define BUILTIN(ID, TYPE, ATTRS)
#define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \
case Builtin::BI##ID: \
return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID);
#include "clang/Basic/Builtins.def"
case Builtin::BI__builtin_annotation:
if (SemaBuiltinAnnotation(*this, TheCall))
return ExprError();
break;
case Builtin::BI__builtin_addressof:
if (SemaBuiltinAddressof(*this, TheCall))
return ExprError();
break;
case Builtin::BI__builtin_operator_new:
case Builtin::BI__builtin_operator_delete:
if (!getLangOpts().CPlusPlus) {
Diag(TheCall->getExprLoc(), diag::err_builtin_requires_language)
<< (BuiltinID == Builtin::BI__builtin_operator_new
? "__builtin_operator_new"
: "__builtin_operator_delete")
<< "C++";
return ExprError();
}
// CodeGen assumes it can find the global new and delete to call,
// so ensure that they are declared.
DeclareGlobalNewDelete();
break;
}
// Since the target specific builtins for each arch overlap, only check those
// of the arch we are compiling for.
if (BuiltinID >= Builtin::FirstTSBuiltin) {
switch (Context.getTargetInfo().getTriple().getArch()) {
case llvm::Triple::arm:
case llvm::Triple::armeb:
case llvm::Triple::thumb:
case llvm::Triple::thumbeb:
if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall))
return ExprError();
break;
case llvm::Triple::aarch64:
case llvm::Triple::aarch64_be:
case llvm::Triple::arm64:
case llvm::Triple::arm64_be:
if (CheckAArch64BuiltinFunctionCall(BuiltinID, TheCall))
return ExprError();
break;
case llvm::Triple::mips:
case llvm::Triple::mipsel:
case llvm::Triple::mips64:
case llvm::Triple::mips64el:
if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall))
return ExprError();
break;
case llvm::Triple::x86:
case llvm::Triple::x86_64:
if (CheckX86BuiltinFunctionCall(BuiltinID, TheCall))
return ExprError();
break;
default:
break;
}
}
return TheCallResult;
}
// Get the valid immediate range for the specified NEON type code.
static unsigned RFT(unsigned t, bool shift = false, bool ForceQuad = false) {
NeonTypeFlags Type(t);
int IsQuad = ForceQuad ? true : Type.isQuad();
switch (Type.getEltType()) {
case NeonTypeFlags::Int8:
case NeonTypeFlags::Poly8:
return shift ? 7 : (8 << IsQuad) - 1;
case NeonTypeFlags::Int16:
case NeonTypeFlags::Poly16:
return shift ? 15 : (4 << IsQuad) - 1;
case NeonTypeFlags::Int32:
return shift ? 31 : (2 << IsQuad) - 1;
case NeonTypeFlags::Int64:
case NeonTypeFlags::Poly64:
return shift ? 63 : (1 << IsQuad) - 1;
case NeonTypeFlags::Poly128:
return shift ? 127 : (1 << IsQuad) - 1;
case NeonTypeFlags::Float16:
assert(!shift && "cannot shift float types!");
return (4 << IsQuad) - 1;
case NeonTypeFlags::Float32:
assert(!shift && "cannot shift float types!");
return (2 << IsQuad) - 1;
case NeonTypeFlags::Float64:
assert(!shift && "cannot shift float types!");
return (1 << IsQuad) - 1;
}
llvm_unreachable("Invalid NeonTypeFlag!");
}
/// getNeonEltType - Return the QualType corresponding to the elements of
/// the vector type specified by the NeonTypeFlags. This is used to check
/// the pointer arguments for Neon load/store intrinsics.
static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context,
bool IsPolyUnsigned, bool IsInt64Long) {
switch (Flags.getEltType()) {
case NeonTypeFlags::Int8:
return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy;
case NeonTypeFlags::Int16:
return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy;
case NeonTypeFlags::Int32:
return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy;
case NeonTypeFlags::Int64:
if (IsInt64Long)
return Flags.isUnsigned() ? Context.UnsignedLongTy : Context.LongTy;
else
return Flags.isUnsigned() ? Context.UnsignedLongLongTy
: Context.LongLongTy;
case NeonTypeFlags::Poly8:
return IsPolyUnsigned ? Context.UnsignedCharTy : Context.SignedCharTy;
case NeonTypeFlags::Poly16:
return IsPolyUnsigned ? Context.UnsignedShortTy : Context.ShortTy;
case NeonTypeFlags::Poly64:
return Context.UnsignedLongTy;
case NeonTypeFlags::Poly128:
break;
case NeonTypeFlags::Float16:
return Context.HalfTy;
case NeonTypeFlags::Float32:
return Context.FloatTy;
case NeonTypeFlags::Float64:
return Context.DoubleTy;
}
llvm_unreachable("Invalid NeonTypeFlag!");
}
bool Sema::CheckNeonBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
llvm::APSInt Result;
uint64_t mask = 0;
unsigned TV = 0;
int PtrArgNum = -1;
bool HasConstPtr = false;
switch (BuiltinID) {
#define GET_NEON_OVERLOAD_CHECK
#include "clang/Basic/arm_neon.inc"
#undef GET_NEON_OVERLOAD_CHECK
}
// For NEON intrinsics which are overloaded on vector element type, validate
// the immediate which specifies which variant to emit.
unsigned ImmArg = TheCall->getNumArgs()-1;
if (mask) {
if (SemaBuiltinConstantArg(TheCall, ImmArg, Result))
return true;
TV = Result.getLimitedValue(64);
if ((TV > 63) || (mask & (1ULL << TV)) == 0)
return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code)
<< TheCall->getArg(ImmArg)->getSourceRange();
}
if (PtrArgNum >= 0) {
// Check that pointer arguments have the specified type.
Expr *Arg = TheCall->getArg(PtrArgNum);
if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg))
Arg = ICE->getSubExpr();
ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg);
QualType RHSTy = RHS.get()->getType();
llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch();
bool IsPolyUnsigned =
Arch == llvm::Triple::aarch64 || Arch == llvm::Triple::arm64;
bool IsInt64Long =
Context.getTargetInfo().getInt64Type() == TargetInfo::SignedLong;
QualType EltTy =
getNeonEltType(NeonTypeFlags(TV), Context, IsPolyUnsigned, IsInt64Long);
if (HasConstPtr)
EltTy = EltTy.withConst();
QualType LHSTy = Context.getPointerType(EltTy);
AssignConvertType ConvTy;
ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS);
if (RHS.isInvalid())
return true;
if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy,
RHS.get(), AA_Assigning))
return true;
}
// For NEON intrinsics which take an immediate value as part of the
// instruction, range check them here.
unsigned i = 0, l = 0, u = 0;
switch (BuiltinID) {
default:
return false;
#define GET_NEON_IMMEDIATE_CHECK
#include "clang/Basic/arm_neon.inc"
#undef GET_NEON_IMMEDIATE_CHECK
}
return SemaBuiltinConstantArgRange(TheCall, i, l, u + l);
}
bool Sema::CheckARMBuiltinExclusiveCall(unsigned BuiltinID, CallExpr *TheCall,
unsigned MaxWidth) {
assert((BuiltinID == ARM::BI__builtin_arm_ldrex ||
BuiltinID == ARM::BI__builtin_arm_ldaex ||
BuiltinID == ARM::BI__builtin_arm_strex ||
BuiltinID == ARM::BI__builtin_arm_stlex ||
BuiltinID == AArch64::BI__builtin_arm_ldrex ||
BuiltinID == AArch64::BI__builtin_arm_ldaex ||
BuiltinID == AArch64::BI__builtin_arm_strex ||
BuiltinID == AArch64::BI__builtin_arm_stlex) &&
"unexpected ARM builtin");
bool IsLdrex = BuiltinID == ARM::BI__builtin_arm_ldrex ||
BuiltinID == ARM::BI__builtin_arm_ldaex ||
BuiltinID == AArch64::BI__builtin_arm_ldrex ||
BuiltinID == AArch64::BI__builtin_arm_ldaex;
DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
// Ensure that we have the proper number of arguments.
if (checkArgCount(*this, TheCall, IsLdrex ? 1 : 2))
return true;
// Inspect the pointer argument of the atomic builtin. This should always be
// a pointer type, whose element is an integral scalar or pointer type.
// Because it is a pointer type, we don't have to worry about any implicit
// casts here.
Expr *PointerArg = TheCall->getArg(IsLdrex ? 0 : 1);
ExprResult PointerArgRes = DefaultFunctionArrayLvalueConversion(PointerArg);
if (PointerArgRes.isInvalid())
return true;
PointerArg = PointerArgRes.get();
const PointerType *pointerType = PointerArg->getType()->getAs<PointerType>();
if (!pointerType) {
Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
<< PointerArg->getType() << PointerArg->getSourceRange();
return true;
}
// ldrex takes a "const volatile T*" and strex takes a "volatile T*". Our next
// task is to insert the appropriate casts into the AST. First work out just
// what the appropriate type is.
QualType ValType = pointerType->getPointeeType();
QualType AddrType = ValType.getUnqualifiedType().withVolatile();
if (IsLdrex)
AddrType.addConst();
// Issue a warning if the cast is dodgy.
CastKind CastNeeded = CK_NoOp;
if (!AddrType.isAtLeastAsQualifiedAs(ValType)) {
CastNeeded = CK_BitCast;
Diag(DRE->getLocStart(), diag::ext_typecheck_convert_discards_qualifiers)
<< PointerArg->getType()
<< Context.getPointerType(AddrType)
<< AA_Passing << PointerArg->getSourceRange();
}
// Finally, do the cast and replace the argument with the corrected version.
AddrType = Context.getPointerType(AddrType);
PointerArgRes = ImpCastExprToType(PointerArg, AddrType, CastNeeded);
if (PointerArgRes.isInvalid())
return true;
PointerArg = PointerArgRes.get();
TheCall->setArg(IsLdrex ? 0 : 1, PointerArg);
// In general, we allow ints, floats and pointers to be loaded and stored.
if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
!ValType->isBlockPointerType() && !ValType->isFloatingType()) {
Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intfltptr)
<< PointerArg->getType() << PointerArg->getSourceRange();
return true;
}
// But ARM doesn't have instructions to deal with 128-bit versions.
if (Context.getTypeSize(ValType) > MaxWidth) {
assert(MaxWidth == 64 && "Diagnostic unexpectedly inaccurate");
Diag(DRE->getLocStart(), diag::err_atomic_exclusive_builtin_pointer_size)
<< PointerArg->getType() << PointerArg->getSourceRange();
return true;
}
switch (ValType.getObjCLifetime()) {
case Qualifiers::OCL_None:
case Qualifiers::OCL_ExplicitNone:
// okay
break;
case Qualifiers::OCL_Weak:
case Qualifiers::OCL_Strong:
case Qualifiers::OCL_Autoreleasing:
Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
<< ValType << PointerArg->getSourceRange();
return true;
}
if (IsLdrex) {
TheCall->setType(ValType);
return false;
}
// Initialize the argument to be stored.
ExprResult ValArg = TheCall->getArg(0);
InitializedEntity Entity = InitializedEntity::InitializeParameter(
Context, ValType, /*consume*/ false);
ValArg = PerformCopyInitialization(Entity, SourceLocation(), ValArg);
if (ValArg.isInvalid())
return true;
TheCall->setArg(0, ValArg.get());
// __builtin_arm_strex always returns an int. It's marked as such in the .def,
// but the custom checker bypasses all default analysis.
TheCall->setType(Context.IntTy);
return false;
}
bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
llvm::APSInt Result;
if (BuiltinID == ARM::BI__builtin_arm_ldrex ||
BuiltinID == ARM::BI__builtin_arm_ldaex ||
BuiltinID == ARM::BI__builtin_arm_strex ||
BuiltinID == ARM::BI__builtin_arm_stlex) {
return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 64);
}
if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall))
return true;
// For intrinsics which take an immediate value as part of the instruction,
// range check them here.
unsigned i = 0, l = 0, u = 0;
switch (BuiltinID) {
default: return false;
case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break;
case ARM::BI__builtin_arm_usat: i = 1; u = 31; break;
case ARM::BI__builtin_arm_vcvtr_f:
case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break;
case ARM::BI__builtin_arm_dmb:
case ARM::BI__builtin_arm_dsb:
case ARM::BI__builtin_arm_isb: l = 0; u = 15; break;
}
// FIXME: VFP Intrinsics should error if VFP not present.
return SemaBuiltinConstantArgRange(TheCall, i, l, u + l);
}
bool Sema::CheckAArch64BuiltinFunctionCall(unsigned BuiltinID,
CallExpr *TheCall) {
llvm::APSInt Result;
if (BuiltinID == AArch64::BI__builtin_arm_ldrex ||
BuiltinID == AArch64::BI__builtin_arm_ldaex ||
BuiltinID == AArch64::BI__builtin_arm_strex ||
BuiltinID == AArch64::BI__builtin_arm_stlex) {
return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 128);
}
if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall))
return true;
return false;
}
bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
unsigned i = 0, l = 0, u = 0;
switch (BuiltinID) {
default: return false;
case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break;
case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break;
case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break;
case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break;
case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break;
case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break;
case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break;
}
return SemaBuiltinConstantArgRange(TheCall, i, l, u);
}
bool Sema::CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
switch (BuiltinID) {
case X86::BI_mm_prefetch:
// This is declared to take (const char*, int)
return SemaBuiltinConstantArgRange(TheCall, 1, 0, 3);
}
return false;
}
/// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo
/// parameter with the FormatAttr's correct format_idx and firstDataArg.
/// Returns true when the format fits the function and the FormatStringInfo has
/// been populated.
bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember,
FormatStringInfo *FSI) {
FSI->HasVAListArg = Format->getFirstArg() == 0;
FSI->FormatIdx = Format->getFormatIdx() - 1;
FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1;
// The way the format attribute works in GCC, the implicit this argument
// of member functions is counted. However, it doesn't appear in our own
// lists, so decrement format_idx in that case.
if (IsCXXMember) {
if(FSI->FormatIdx == 0)
return false;
--FSI->FormatIdx;
if (FSI->FirstDataArg != 0)
--FSI->FirstDataArg;
}
return true;
}
/// Checks if a the given expression evaluates to null.
///
/// \brief Returns true if the value evaluates to null.
static bool CheckNonNullExpr(Sema &S,
const Expr *Expr) {
// As a special case, transparent unions initialized with zero are
// considered null for the purposes of the nonnull attribute.
if (const RecordType *UT = Expr->getType()->getAsUnionType()) {
if (UT->getDecl()->hasAttr<TransparentUnionAttr>())
if (const CompoundLiteralExpr *CLE =
dyn_cast<CompoundLiteralExpr>(Expr))
if (const InitListExpr *ILE =
dyn_cast<InitListExpr>(CLE->getInitializer()))
Expr = ILE->getInit(0);
}
bool Result;
return (!Expr->isValueDependent() &&
Expr->EvaluateAsBooleanCondition(Result, S.Context) &&
!Result);
}
static void CheckNonNullArgument(Sema &S,
const Expr *ArgExpr,
SourceLocation CallSiteLoc) {
if (CheckNonNullExpr(S, ArgExpr))
S.Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange();
}
static void CheckNonNullArguments(Sema &S,
const NamedDecl *FDecl,
const Expr * const *ExprArgs,
SourceLocation CallSiteLoc) {
// Check the attributes attached to the method/function itself.
for (const auto *NonNull : FDecl->specific_attrs<NonNullAttr>()) {
for (const auto &Val : NonNull->args())
CheckNonNullArgument(S, ExprArgs[Val], CallSiteLoc);
}
// Check the attributes on the parameters.
ArrayRef<ParmVarDecl*> parms;
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(FDecl))
parms = FD->parameters();
else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(FDecl))
parms = MD->parameters();
unsigned argIndex = 0;
for (ArrayRef<ParmVarDecl*>::iterator I = parms.begin(), E = parms.end();
I != E; ++I, ++argIndex) {
const ParmVarDecl *PVD = *I;
if (PVD->hasAttr<NonNullAttr>())
CheckNonNullArgument(S, ExprArgs[argIndex], CallSiteLoc);
}
}
/// Handles the checks for format strings, non-POD arguments to vararg
/// functions, and NULL arguments passed to non-NULL parameters.
void Sema::checkCall(NamedDecl *FDecl, ArrayRef<const Expr *> Args,
unsigned NumParams, bool IsMemberFunction,
SourceLocation Loc, SourceRange Range,
VariadicCallType CallType) {
// FIXME: We should check as much as we can in the template definition.
if (CurContext->isDependentContext())
return;
// Printf and scanf checking.
llvm::SmallBitVector CheckedVarArgs;
if (FDecl) {
for (const auto *I : FDecl->specific_attrs<FormatAttr>()) {
// Only create vector if there are format attributes.
CheckedVarArgs.resize(Args.size());
CheckFormatArguments(I, Args, IsMemberFunction, CallType, Loc, Range,
CheckedVarArgs);
}
}
// Refuse POD arguments that weren't caught by the format string
// checks above.
if (CallType != VariadicDoesNotApply) {
for (unsigned ArgIdx = NumParams; ArgIdx < Args.size(); ++ArgIdx) {
// Args[ArgIdx] can be null in malformed code.
if (const Expr *Arg = Args[ArgIdx]) {
if (CheckedVarArgs.empty() || !CheckedVarArgs[ArgIdx])
checkVariadicArgument(Arg, CallType);
}
}
}
if (FDecl) {
CheckNonNullArguments(*this, FDecl, Args.data(), Loc);
// Type safety checking.
for (const auto *I : FDecl->specific_attrs<ArgumentWithTypeTagAttr>())
CheckArgumentWithTypeTag(I, Args.data());
}
}
/// CheckConstructorCall - Check a constructor call for correctness and safety
/// properties not enforced by the C type system.
void Sema::CheckConstructorCall(FunctionDecl *FDecl,
ArrayRef<const Expr *> Args,
const FunctionProtoType *Proto,
SourceLocation Loc) {
VariadicCallType CallType =
Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply;
checkCall(FDecl, Args, Proto->getNumParams(),
/*IsMemberFunction=*/true, Loc, SourceRange(), CallType);
}
/// CheckFunctionCall - Check a direct function call for various correctness
/// and safety properties not strictly enforced by the C type system.
bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall,
const FunctionProtoType *Proto) {
bool IsMemberOperatorCall = isa<CXXOperatorCallExpr>(TheCall) &&
isa<CXXMethodDecl>(FDecl);
bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall) ||
IsMemberOperatorCall;
VariadicCallType CallType = getVariadicCallType(FDecl, Proto,
TheCall->getCallee());
unsigned NumParams = Proto ? Proto->getNumParams() : 0;
Expr** Args = TheCall->getArgs();
unsigned NumArgs = TheCall->getNumArgs();
if (IsMemberOperatorCall) {
// If this is a call to a member operator, hide the first argument
// from checkCall.
// FIXME: Our choice of AST representation here is less than ideal.
++Args;
--NumArgs;
}
checkCall(FDecl, llvm::makeArrayRef<const Expr *>(Args, NumArgs), NumParams,
IsMemberFunction, TheCall->getRParenLoc(),
TheCall->getCallee()->getSourceRange(), CallType);
IdentifierInfo *FnInfo = FDecl->getIdentifier();
// None of the checks below are needed for functions that don't have
// simple names (e.g., C++ conversion functions).
if (!FnInfo)
return false;
CheckAbsoluteValueFunction(TheCall, FDecl, FnInfo);
unsigned CMId = FDecl->getMemoryFunctionKind();
if (CMId == 0)
return false;
// Handle memory setting and copying functions.
if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat)
CheckStrlcpycatArguments(TheCall, FnInfo);
else if (CMId == Builtin::BIstrncat)
CheckStrncatArguments(TheCall, FnInfo);
else
CheckMemaccessArguments(TheCall, CMId, FnInfo);
return false;
}
bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac,
ArrayRef<const Expr *> Args) {
VariadicCallType CallType =
Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply;
checkCall(Method, Args, Method->param_size(),
/*IsMemberFunction=*/false,
lbrac, Method->getSourceRange(), CallType);
return false;
}
bool Sema::CheckPointerCall(NamedDecl *NDecl, CallExpr *TheCall,
const FunctionProtoType *Proto) {
const VarDecl *V = dyn_cast<VarDecl>(NDecl);
if (!V)
return false;
QualType Ty = V->getType();
if (!Ty->isBlockPointerType() && !Ty->isFunctionPointerType())
return false;
VariadicCallType CallType;
if (!Proto || !Proto->isVariadic()) {
CallType = VariadicDoesNotApply;
} else if (Ty->isBlockPointerType()) {
CallType = VariadicBlock;
} else { // Ty->isFunctionPointerType()
CallType = VariadicFunction;
}
unsigned NumParams = Proto ? Proto->getNumParams() : 0;
checkCall(NDecl, llvm::makeArrayRef<const Expr *>(TheCall->getArgs(),
TheCall->getNumArgs()),
NumParams, /*IsMemberFunction=*/false, TheCall->getRParenLoc(),
TheCall->getCallee()->getSourceRange(), CallType);
return false;
}
/// Checks function calls when a FunctionDecl or a NamedDecl is not available,
/// such as function pointers returned from functions.
bool Sema::CheckOtherCall(CallExpr *TheCall, const FunctionProtoType *Proto) {
VariadicCallType CallType = getVariadicCallType(/*FDecl=*/nullptr, Proto,
TheCall->getCallee());
unsigned NumParams = Proto ? Proto->getNumParams() : 0;
checkCall(/*FDecl=*/nullptr,
llvm::makeArrayRef<const Expr *>(TheCall->getArgs(),
TheCall->getNumArgs()),
NumParams, /*IsMemberFunction=*/false, TheCall->getRParenLoc(),
TheCall->getCallee()->getSourceRange(), CallType);
return false;
}
static bool isValidOrderingForOp(int64_t Ordering, AtomicExpr::AtomicOp Op) {
if (Ordering < AtomicExpr::AO_ABI_memory_order_relaxed ||
Ordering > AtomicExpr::AO_ABI_memory_order_seq_cst)
return false;
switch (Op) {
case AtomicExpr::AO__c11_atomic_init:
llvm_unreachable("There is no ordering argument for an init");
case AtomicExpr::AO__c11_atomic_load:
case AtomicExpr::AO__atomic_load_n:
case AtomicExpr::AO__atomic_load:
return Ordering != AtomicExpr::AO_ABI_memory_order_release &&
Ordering != AtomicExpr::AO_ABI_memory_order_acq_rel;
case AtomicExpr::AO__c11_atomic_store:
case AtomicExpr::AO__atomic_store:
case AtomicExpr::AO__atomic_store_n:
return Ordering != AtomicExpr::AO_ABI_memory_order_consume &&
Ordering != AtomicExpr::AO_ABI_memory_order_acquire &&
Ordering != AtomicExpr::AO_ABI_memory_order_acq_rel;
default:
return true;
}
}
ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
AtomicExpr::AtomicOp Op) {
CallExpr *TheCall = cast<CallExpr>(TheCallResult.get());
DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
// All these operations take one of the following forms:
enum {
// C __c11_atomic_init(A *, C)
Init,
// C __c11_atomic_load(A *, int)
Load,
// void __atomic_load(A *, CP, int)
Copy,
// C __c11_atomic_add(A *, M, int)
Arithmetic,
// C __atomic_exchange_n(A *, CP, int)
Xchg,
// void __atomic_exchange(A *, C *, CP, int)
GNUXchg,
// bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int)
C11CmpXchg,
// bool __atomic_compare_exchange(A *, C *, CP, bool, int, int)
GNUCmpXchg
} Form = Init;
const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 };
const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 };
// where:
// C is an appropriate type,
// A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins,
// CP is C for __c11 builtins and GNU _n builtins and is C * otherwise,
// M is C if C is an integer, and ptrdiff_t if C is a pointer, and
// the int parameters are for orderings.
assert(AtomicExpr::AO__c11_atomic_init == 0 &&
AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load
&& "need to update code for modified C11 atomics");
bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init &&
Op <= AtomicExpr::AO__c11_atomic_fetch_xor;
bool IsN = Op == AtomicExpr::AO__atomic_load_n ||
Op == AtomicExpr::AO__atomic_store_n ||
Op == AtomicExpr::AO__atomic_exchange_n ||
Op == AtomicExpr::AO__atomic_compare_exchange_n;
bool IsAddSub = false;
switch (Op) {
case AtomicExpr::AO__c11_atomic_init:
Form = Init;
break;
case AtomicExpr::AO__c11_atomic_load:
case AtomicExpr::AO__atomic_load_n:
Form = Load;
break;
case AtomicExpr::AO__c11_atomic_store:
case AtomicExpr::AO__atomic_load:
case AtomicExpr::AO__atomic_store:
case AtomicExpr::AO__atomic_store_n:
Form = Copy;
break;
case AtomicExpr::AO__c11_atomic_fetch_add:
case AtomicExpr::AO__c11_atomic_fetch_sub:
case AtomicExpr::AO__atomic_fetch_add:
case AtomicExpr::AO__atomic_fetch_sub:
case AtomicExpr::AO__atomic_add_fetch:
case AtomicExpr::AO__atomic_sub_fetch:
IsAddSub = true;
// Fall through.
case AtomicExpr::AO__c11_atomic_fetch_and:
case AtomicExpr::AO__c11_atomic_fetch_or:
case AtomicExpr::AO__c11_atomic_fetch_xor:
case AtomicExpr::AO__atomic_fetch_and:
case AtomicExpr::AO__atomic_fetch_or:
case AtomicExpr::AO__atomic_fetch_xor:
case AtomicExpr::AO__atomic_fetch_nand:
case AtomicExpr::AO__atomic_and_fetch:
case AtomicExpr::AO__atomic_or_fetch:
case AtomicExpr::AO__atomic_xor_fetch:
case AtomicExpr::AO__atomic_nand_fetch:
Form = Arithmetic;
break;
case AtomicExpr::AO__c11_atomic_exchange:
case AtomicExpr::AO__atomic_exchange_n:
Form = Xchg;
break;
case AtomicExpr::AO__atomic_exchange:
Form = GNUXchg;
break;
case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
Form = C11CmpXchg;
break;
case AtomicExpr::AO__atomic_compare_exchange:
case AtomicExpr::AO__atomic_compare_exchange_n:
Form = GNUCmpXchg;
break;
}
// Check we have the right number of arguments.
if (TheCall->getNumArgs() < NumArgs[Form]) {
Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
<< 0 << NumArgs[Form] << TheCall->getNumArgs()
<< TheCall->getCallee()->getSourceRange();
return ExprError();
} else if (TheCall->getNumArgs() > NumArgs[Form]) {
Diag(TheCall->getArg(NumArgs[Form])->getLocStart(),
diag::err_typecheck_call_too_many_args)
<< 0 << NumArgs[Form] << TheCall->getNumArgs()
<< TheCall->getCallee()->getSourceRange();
return ExprError();
}
// Inspect the first argument of the atomic operation.
Expr *Ptr = TheCall->getArg(0);
Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get();
const PointerType *pointerType = Ptr->getType()->getAs<PointerType>();
if (!pointerType) {
Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
<< Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
// For a __c11 builtin, this should be a pointer to an _Atomic type.
QualType AtomTy = pointerType->getPointeeType(); // 'A'
QualType ValType = AtomTy; // 'C'
if (IsC11) {
if (!AtomTy->isAtomicType()) {
Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic)
<< Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
if (AtomTy.isConstQualified()) {
Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic)
<< Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
ValType = AtomTy->getAs<AtomicType>()->getValueType();
}
// For an arithmetic operation, the implied arithmetic must be well-formed.
if (Form == Arithmetic) {
// gcc does not enforce these rules for GNU atomics, but we do so for sanity.
if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) {
Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
<< IsC11 << Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
if (!IsAddSub && !ValType->isIntegerType()) {
Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int)
<< IsC11 << Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
} else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) {
// For __atomic_*_n operations, the value type must be a scalar integral or
// pointer type which is 1, 2, 4, 8 or 16 bytes in length.
Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
<< IsC11 << Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context) &&
!AtomTy->isScalarType()) {
// For GNU atomics, require a trivially-copyable type. This is not part of
// the GNU atomics specification, but we enforce it for sanity.
Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy)
<< Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
// FIXME: For any builtin other than a load, the ValType must not be
// const-qualified.
switch (ValType.getObjCLifetime()) {
case Qualifiers::OCL_None:
case Qualifiers::OCL_ExplicitNone:
// okay
break;
case Qualifiers::OCL_Weak:
case Qualifiers::OCL_Strong:
case Qualifiers::OCL_Autoreleasing:
// FIXME: Can this happen? By this point, ValType should be known
// to be trivially copyable.
Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
<< ValType << Ptr->getSourceRange();
return ExprError();
}
QualType ResultType = ValType;
if (Form == Copy || Form == GNUXchg || Form == Init)
ResultType = Context.VoidTy;
else if (Form == C11CmpXchg || Form == GNUCmpXchg)
ResultType = Context.BoolTy;
// The type of a parameter passed 'by value'. In the GNU atomics, such
// arguments are actually passed as pointers.
QualType ByValType = ValType; // 'CP'
if (!IsC11 && !IsN)
ByValType = Ptr->getType();
// The first argument --- the pointer --- has a fixed type; we
// deduce the types of the rest of the arguments accordingly. Walk
// the remaining arguments, converting them to the deduced value type.
for (unsigned i = 1; i != NumArgs[Form]; ++i) {
QualType Ty;
if (i < NumVals[Form] + 1) {
switch (i) {
case 1:
// The second argument is the non-atomic operand. For arithmetic, this
// is always passed by value, and for a compare_exchange it is always
// passed by address. For the rest, GNU uses by-address and C11 uses
// by-value.
assert(Form != Load);
if (Form == Init || (Form == Arithmetic && ValType->isIntegerType()))
Ty = ValType;
else if (Form == Copy || Form == Xchg)
Ty = ByValType;
else if (Form == Arithmetic)
Ty = Context.getPointerDiffType();
else
Ty = Context.getPointerType(ValType.getUnqualifiedType());
break;
case 2:
// The third argument to compare_exchange / GNU exchange is a
// (pointer to a) desired value.
Ty = ByValType;
break;
case 3:
// The fourth argument to GNU compare_exchange is a 'weak' flag.
Ty = Context.BoolTy;
break;
}
} else {
// The order(s) are always converted to int.
Ty = Context.IntTy;
}
InitializedEntity Entity =
InitializedEntity::InitializeParameter(Context, Ty, false);
ExprResult Arg = TheCall->getArg(i);
Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
if (Arg.isInvalid())
return true;
TheCall->setArg(i, Arg.get());
}
// Permute the arguments into a 'consistent' order.
SmallVector<Expr*, 5> SubExprs;
SubExprs.push_back(Ptr);
switch (Form) {
case Init:
// Note, AtomicExpr::getVal1() has a special case for this atomic.
SubExprs.push_back(TheCall->getArg(1)); // Val1
break;
case Load:
SubExprs.push_back(TheCall->getArg(1)); // Order
break;
case Copy:
case Arithmetic:
case Xchg:
SubExprs.push_back(TheCall->getArg(2)); // Order
SubExprs.push_back(TheCall->getArg(1)); // Val1
break;
case GNUXchg:
// Note, AtomicExpr::getVal2() has a special case for this atomic.
SubExprs.push_back(TheCall->getArg(3)); // Order
SubExprs.push_back(TheCall->getArg(1)); // Val1
SubExprs.push_back(TheCall->getArg(2)); // Val2
break;
case C11CmpXchg:
SubExprs.push_back(TheCall->getArg(3)); // Order
SubExprs.push_back(TheCall->getArg(1)); // Val1
SubExprs.push_back(TheCall->getArg(4)); // OrderFail
SubExprs.push_back(TheCall->getArg(2)); // Val2
break;
case GNUCmpXchg:
SubExprs.push_back(TheCall->getArg(4)); // Order
SubExprs.push_back(TheCall->getArg(1)); // Val1
SubExprs.push_back(TheCall->getArg(5)); // OrderFail
SubExprs.push_back(TheCall->getArg(2)); // Val2
SubExprs.push_back(TheCall->getArg(3)); // Weak
break;
}
if (SubExprs.size() >= 2 && Form != Init) {
llvm::APSInt Result(32);
if (SubExprs[1]->isIntegerConstantExpr(Result, Context) &&
!isValidOrderingForOp(Result.getSExtValue(), Op))
Diag(SubExprs[1]->getLocStart(),
diag::warn_atomic_op_has_invalid_memory_order)
<< SubExprs[1]->getSourceRange();
}
AtomicExpr *AE = new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(),
SubExprs, ResultType, Op,
TheCall->getRParenLoc());
if ((Op == AtomicExpr::AO__c11_atomic_load ||
(Op == AtomicExpr::AO__c11_atomic_store)) &&
Context.AtomicUsesUnsupportedLibcall(AE))
Diag(AE->getLocStart(), diag::err_atomic_load_store_uses_lib) <<
((Op == AtomicExpr::AO__c11_atomic_load) ? 0 : 1);
return AE;
}
/// checkBuiltinArgument - Given a call to a builtin function, perform
/// normal type-checking on the given argument, updating the call in
/// place. This is useful when a builtin function requires custom
/// type-checking for some of its arguments but not necessarily all of
/// them.
///
/// Returns true on error.
static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) {
FunctionDecl *Fn = E->getDirectCallee();
assert(Fn && "builtin call without direct callee!");
ParmVarDecl *Param = Fn->getParamDecl(ArgIndex);
InitializedEntity Entity =
InitializedEntity::InitializeParameter(S.Context, Param);
ExprResult Arg = E->getArg(0);
Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg);
if (Arg.isInvalid())
return true;
E->setArg(ArgIndex, Arg.get());
return false;
}
/// SemaBuiltinAtomicOverloaded - We have a call to a function like
/// __sync_fetch_and_add, which is an overloaded function based on the pointer
/// type of its first argument. The main ActOnCallExpr routines have already
/// promoted the types of arguments because all of these calls are prototyped as
/// void(...).
///
/// This function goes through and does final semantic checking for these
/// builtins,
ExprResult
Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
CallExpr *TheCall = (CallExpr *)TheCallResult.get();
DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
// Ensure that we have at least one argument to do type inference from.
if (TheCall->getNumArgs() < 1) {
Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
<< 0 << 1 << TheCall->getNumArgs()
<< TheCall->getCallee()->getSourceRange();
return ExprError();
}
// Inspect the first argument of the atomic builtin. This should always be
// a pointer type, whose element is an integral scalar or pointer type.
// Because it is a pointer type, we don't have to worry about any implicit
// casts here.
// FIXME: We don't allow floating point scalars as input.
Expr *FirstArg = TheCall->getArg(0);
ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg);
if (FirstArgResult.isInvalid())
return ExprError();
FirstArg = FirstArgResult.get();
TheCall->setArg(0, FirstArg);
const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>();
if (!pointerType) {
Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
<< FirstArg->getType() << FirstArg->getSourceRange();
return ExprError();
}
QualType ValType = pointerType->getPointeeType();
if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
!ValType->isBlockPointerType()) {
Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr)
<< FirstArg->getType() << FirstArg->getSourceRange();
return ExprError();
}
switch (ValType.getObjCLifetime()) {
case Qualifiers::OCL_None:
case Qualifiers::OCL_ExplicitNone:
// okay
break;
case Qualifiers::OCL_Weak:
case Qualifiers::OCL_Strong:
case Qualifiers::OCL_Autoreleasing:
Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
<< ValType << FirstArg->getSourceRange();
return ExprError();
}
// Strip any qualifiers off ValType.
ValType = ValType.getUnqualifiedType();
// The majority of builtins return a value, but a few have special return
// types, so allow them to override appropriately below.
QualType ResultType = ValType;
// We need to figure out which concrete builtin this maps onto. For example,
// __sync_fetch_and_add with a 2 byte object turns into
// __sync_fetch_and_add_2.
#define BUILTIN_ROW(x) \
{ Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \
Builtin::BI##x##_8, Builtin::BI##x##_16 }
static const unsigned BuiltinIndices[][5] = {
BUILTIN_ROW(__sync_fetch_and_add),
BUILTIN_ROW(__sync_fetch_and_sub),
BUILTIN_ROW(__sync_fetch_and_or),
BUILTIN_ROW(__sync_fetch_and_and),
BUILTIN_ROW(__sync_fetch_and_xor),
BUILTIN_ROW(__sync_add_and_fetch),
BUILTIN_ROW(__sync_sub_and_fetch),
BUILTIN_ROW(__sync_and_and_fetch),
BUILTIN_ROW(__sync_or_and_fetch),
BUILTIN_ROW(__sync_xor_and_fetch),
BUILTIN_ROW(__sync_val_compare_and_swap),
BUILTIN_ROW(__sync_bool_compare_and_swap),
BUILTIN_ROW(__sync_lock_test_and_set),
BUILTIN_ROW(__sync_lock_release),
BUILTIN_ROW(__sync_swap)
};
#undef BUILTIN_ROW
// Determine the index of the size.
unsigned SizeIndex;
switch (Context.getTypeSizeInChars(ValType).getQuantity()) {
case 1: SizeIndex = 0; break;
case 2: SizeIndex = 1; break;
case 4: SizeIndex = 2; break;
case 8: SizeIndex = 3; break;
case 16: SizeIndex = 4; break;
default:
Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size)
<< FirstArg->getType() << FirstArg->getSourceRange();
return ExprError();
}
// Each of these builtins has one pointer argument, followed by some number of
// values (0, 1 or 2) followed by a potentially empty varags list of stuff
// that we ignore. Find out which row of BuiltinIndices to read from as well
// as the number of fixed args.
unsigned BuiltinID = FDecl->getBuiltinID();
unsigned BuiltinIndex, NumFixed = 1;
switch (BuiltinID) {
default: llvm_unreachable("Unknown overloaded atomic builtin!");
case Builtin::BI__sync_fetch_and_add:
case Builtin::BI__sync_fetch_and_add_1:
case Builtin::BI__sync_fetch_and_add_2:
case Builtin::BI__sync_fetch_and_add_4:
case Builtin::BI__sync_fetch_and_add_8:
case Builtin::BI__sync_fetch_and_add_16:
BuiltinIndex = 0;
break;
case Builtin::BI__sync_fetch_and_sub:
case Builtin::BI__sync_fetch_and_sub_1:
case Builtin::BI__sync_fetch_and_sub_2:
case Builtin::BI__sync_fetch_and_sub_4:
case Builtin::BI__sync_fetch_and_sub_8:
case Builtin::BI__sync_fetch_and_sub_16:
BuiltinIndex = 1;
break;
case Builtin::BI__sync_fetch_and_or:
case Builtin::BI__sync_fetch_and_or_1:
case Builtin::BI__sync_fetch_and_or_2:
case Builtin::BI__sync_fetch_and_or_4:
case Builtin::BI__sync_fetch_and_or_8:
case Builtin::BI__sync_fetch_and_or_16:
BuiltinIndex = 2;
break;
case Builtin::BI__sync_fetch_and_and:
case Builtin::BI__sync_fetch_and_and_1:
case Builtin::BI__sync_fetch_and_and_2:
case Builtin::BI__sync_fetch_and_and_4:
case Builtin::BI__sync_fetch_and_and_8:
case Builtin::BI__sync_fetch_and_and_16:
BuiltinIndex = 3;
break;
case Builtin::BI__sync_fetch_and_xor:
case Builtin::BI__sync_fetch_and_xor_1:
case Builtin::BI__sync_fetch_and_xor_2:
case Builtin::BI__sync_fetch_and_xor_4:
case Builtin::BI__sync_fetch_and_xor_8:
case Builtin::BI__sync_fetch_and_xor_16:
BuiltinIndex = 4;
break;
case Builtin::BI__sync_add_and_fetch:
case Builtin::BI__sync_add_and_fetch_1:
case Builtin::BI__sync_add_and_fetch_2:
case Builtin::BI__sync_add_and_fetch_4:
case Builtin::BI__sync_add_and_fetch_8:
case Builtin::BI__sync_add_and_fetch_16:
BuiltinIndex = 5;
break;
case Builtin::BI__sync_sub_and_fetch:
case Builtin::BI__sync_sub_and_fetch_1:
case Builtin::BI__sync_sub_and_fetch_2:
case Builtin::BI__sync_sub_and_fetch_4:
case Builtin::BI__sync_sub_and_fetch_8:
case Builtin::BI__sync_sub_and_fetch_16:
BuiltinIndex = 6;
break;
case Builtin::BI__sync_and_and_fetch:
case Builtin::BI__sync_and_and_fetch_1:
case Builtin::BI__sync_and_and_fetch_2:
case Builtin::BI__sync_and_and_fetch_4:
case Builtin::BI__sync_and_and_fetch_8:
case Builtin::BI__sync_and_and_fetch_16:
BuiltinIndex = 7;
break;
case Builtin::BI__sync_or_and_fetch:
case Builtin::BI__sync_or_and_fetch_1:
case Builtin::BI__sync_or_and_fetch_2:
case Builtin::BI__sync_or_and_fetch_4:
case Builtin::BI__sync_or_and_fetch_8:
case Builtin::BI__sync_or_and_fetch_16:
BuiltinIndex = 8;
break;
case Builtin::BI__sync_xor_and_fetch:
case Builtin::BI__sync_xor_and_fetch_1:
case Builtin::BI__sync_xor_and_fetch_2:
case Builtin::BI__sync_xor_and_fetch_4:
case Builtin::BI__sync_xor_and_fetch_8:
case Builtin::BI__sync_xor_and_fetch_16:
BuiltinIndex = 9;
break;
case Builtin::BI__sync_val_compare_and_swap:
case Builtin::BI__sync_val_compare_and_swap_1:
case Builtin::BI__sync_val_compare_and_swap_2:
case Builtin::BI__sync_val_compare_and_swap_4:
case Builtin::BI__sync_val_compare_and_swap_8:
case Builtin::BI__sync_val_compare_and_swap_16:
BuiltinIndex = 10;
NumFixed = 2;
break;
case Builtin::BI__sync_bool_compare_and_swap:
case Builtin::BI__sync_bool_compare_and_swap_1:
case Builtin::BI__sync_bool_compare_and_swap_2:
case Builtin::BI__sync_bool_compare_and_swap_4:
case Builtin::BI__sync_bool_compare_and_swap_8:
case Builtin::BI__sync_bool_compare_and_swap_16:
BuiltinIndex = 11;
NumFixed = 2;
ResultType = Context.BoolTy;
break;
case Builtin::BI__sync_lock_test_and_set:
case Builtin::BI__sync_lock_test_and_set_1:
case Builtin::BI__sync_lock_test_and_set_2:
case Builtin::BI__sync_lock_test_and_set_4:
case Builtin::BI__sync_lock_test_and_set_8:
case Builtin::BI__sync_lock_test_and_set_16:
BuiltinIndex = 12;
break;
case Builtin::BI__sync_lock_release:
case Builtin::BI__sync_lock_release_1:
case Builtin::BI__sync_lock_release_2:
case Builtin::BI__sync_lock_release_4:
case Builtin::BI__sync_lock_release_8:
case Builtin::BI__sync_lock_release_16:
BuiltinIndex = 13;
NumFixed = 0;
ResultType = Context.VoidTy;
break;
case Builtin::BI__sync_swap:
case Builtin::BI__sync_swap_1:
case Builtin::BI__sync_swap_2:
case Builtin::BI__sync_swap_4:
case Builtin::BI__sync_swap_8:
case Builtin::BI__sync_swap_16:
BuiltinIndex = 14;
break;
}
// Now that we know how many fixed arguments we expect, first check that we
// have at least that many.
if (TheCall->getNumArgs() < 1+NumFixed) {
Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
<< 0 << 1+NumFixed << TheCall->getNumArgs()
<< TheCall->getCallee()->getSourceRange();
return ExprError();
}
// Get the decl for the concrete builtin from this, we can tell what the
// concrete integer type we should convert to is.
unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID);
FunctionDecl *NewBuiltinDecl;
if (NewBuiltinID == BuiltinID)
NewBuiltinDecl = FDecl;
else {
// Perform builtin lookup to avoid redeclaring it.
DeclarationName DN(&Context.Idents.get(NewBuiltinName));
LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName);
LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true);
assert(Res.getFoundDecl());
NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl());
if (!NewBuiltinDecl)
return ExprError();
}
// The first argument --- the pointer --- has a fixed type; we
// deduce the types of the rest of the arguments accordingly. Walk
// the remaining arguments, converting them to the deduced value type.
for (unsigned i = 0; i != NumFixed; ++i) {
ExprResult Arg = TheCall->getArg(i+1);
// GCC does an implicit conversion to the pointer or integer ValType. This
// can fail in some cases (1i -> int**), check for this error case now.
// Initialize the argument.
InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
ValType, /*consume*/ false);
Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
if (Arg.isInvalid())
return ExprError();
// Okay, we have something that *can* be converted to the right type. Check
// to see if there is a potentially weird extension going on here. This can
// happen when you do an atomic operation on something like an char* and
// pass in 42. The 42 gets converted to char. This is even more strange
// for things like 45.123 -> char, etc.
// FIXME: Do this check.
TheCall->setArg(i+1, Arg.get());
}
ASTContext& Context = this->getASTContext();
// Create a new DeclRefExpr to refer to the new decl.
DeclRefExpr* NewDRE = DeclRefExpr::Create(
Context,
DRE->getQualifierLoc(),
SourceLocation(),
NewBuiltinDecl,
/*enclosing*/ false,
DRE->getLocation(),
Context.BuiltinFnTy,
DRE->getValueKind());
// Set the callee in the CallExpr.
// FIXME: This loses syntactic information.
QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType());
ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy,
CK_BuiltinFnToFnPtr);
TheCall->setCallee(PromotedCall.get());
// Change the result type of the call to match the original value type. This
// is arbitrary, but the codegen for these builtins ins design to handle it
// gracefully.
TheCall->setType(ResultType);
return TheCallResult;
}
/// CheckObjCString - Checks that the argument to the builtin
/// CFString constructor is correct
/// Note: It might also make sense to do the UTF-16 conversion here (would
/// simplify the backend).
bool Sema::CheckObjCString(Expr *Arg) {
Arg = Arg->IgnoreParenCasts();
StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
if (!Literal || !Literal->isAscii()) {
Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant)
<< Arg->getSourceRange();
return true;
}
if (Literal->containsNonAsciiOrNull()) {
StringRef String = Literal->getString();
unsigned NumBytes = String.size();
SmallVector<UTF16, 128> ToBuf(NumBytes);
const UTF8 *FromPtr = (const UTF8 *)String.data();
UTF16 *ToPtr = &ToBuf[0];
ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,
&ToPtr, ToPtr + NumBytes,
strictConversion);
// Check for conversion failure.
if (Result != conversionOK)
Diag(Arg->getLocStart(),
diag::warn_cfstring_truncated) << Arg->getSourceRange();
}
return false;
}
/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity.
/// Emit an error and return true on failure, return false on success.
bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) {
Expr *Fn = TheCall->getCallee();
if (TheCall->getNumArgs() > 2) {
Diag(TheCall->getArg(2)->getLocStart(),
diag::err_typecheck_call_too_many_args)
<< 0 /*function call*/ << 2 << TheCall->getNumArgs()
<< Fn->getSourceRange()
<< SourceRange(TheCall->getArg(2)->getLocStart(),
(*(TheCall->arg_end()-1))->getLocEnd());
return true;
}
if (TheCall->getNumArgs() < 2) {
return Diag(TheCall->getLocEnd(),
diag::err_typecheck_call_too_few_args_at_least)
<< 0 /*function call*/ << 2 << TheCall->getNumArgs();
}
// Type-check the first argument normally.
if (checkBuiltinArgument(*this, TheCall, 0))
return true;
// Determine whether the current function is variadic or not.
BlockScopeInfo *CurBlock = getCurBlock();
bool isVariadic;
if (CurBlock)
isVariadic = CurBlock->TheDecl->isVariadic();
else if (FunctionDecl *FD = getCurFunctionDecl())
isVariadic = FD->isVariadic();
else
isVariadic = getCurMethodDecl()->isVariadic();
if (!isVariadic) {
Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
return true;
}
// Verify that the second argument to the builtin is the last argument of the
// current function or method.
bool SecondArgIsLastNamedArgument = false;
const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts();
// These are valid if SecondArgIsLastNamedArgument is false after the next
// block.
QualType Type;
SourceLocation ParamLoc;
if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) {
if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) {
// FIXME: This isn't correct for methods (results in bogus warning).
// Get the last formal in the current function.
const ParmVarDecl *LastArg;
if (CurBlock)
LastArg = *(CurBlock->TheDecl->param_end()-1);
else if (FunctionDecl *FD = getCurFunctionDecl())
LastArg = *(FD->param_end()-1);
else
LastArg = *(getCurMethodDecl()->param_end()-1);
SecondArgIsLastNamedArgument = PV == LastArg;
Type = PV->getType();
ParamLoc = PV->getLocation();
}
}
if (!SecondArgIsLastNamedArgument)
Diag(TheCall->getArg(1)->getLocStart(),
diag::warn_second_parameter_of_va_start_not_last_named_argument);
else if (Type->isReferenceType()) {
Diag(Arg->getLocStart(),
diag::warn_va_start_of_reference_type_is_undefined);
Diag(ParamLoc, diag::note_parameter_type) << Type;
}
TheCall->setType(Context.VoidTy);
return false;
}
/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
/// friends. This is declared to take (...), so we have to check everything.
bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) {
if (TheCall->getNumArgs() < 2)
return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
<< 0 << 2 << TheCall->getNumArgs()/*function call*/;
if (TheCall->getNumArgs() > 2)
return Diag(TheCall->getArg(2)->getLocStart(),
diag::err_typecheck_call_too_many_args)
<< 0 /*function call*/ << 2 << TheCall->getNumArgs()
<< SourceRange(TheCall->getArg(2)->getLocStart(),
(*(TheCall->arg_end()-1))->getLocEnd());
ExprResult OrigArg0 = TheCall->getArg(0);
ExprResult OrigArg1 = TheCall->getArg(1);
// Do standard promotions between the two arguments, returning their common
// type.
QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false);
if (OrigArg0.isInvalid() || OrigArg1.isInvalid())
return true;
// Make sure any conversions are pushed back into the call; this is
// type safe since unordered compare builtins are declared as "_Bool
// foo(...)".
TheCall->setArg(0, OrigArg0.get());
TheCall->setArg(1, OrigArg1.get());
if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent())
return false;
// If the common type isn't a real floating type, then the arguments were
// invalid for this operation.
if (Res.isNull() || !Res->isRealFloatingType())
return Diag(OrigArg0.get()->getLocStart(),
diag::err_typecheck_call_invalid_ordered_compare)
<< OrigArg0.get()->getType() << OrigArg1.get()->getType()
<< SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd());
return false;
}
/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like
/// __builtin_isnan and friends. This is declared to take (...), so we have
/// to check everything. We expect the last argument to be a floating point
/// value.
bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
if (TheCall->getNumArgs() < NumArgs)
return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
<< 0 << NumArgs << TheCall->getNumArgs()/*function call*/;
if (TheCall->getNumArgs() > NumArgs)
return Diag(TheCall->getArg(NumArgs)->getLocStart(),
diag::err_typecheck_call_too_many_args)
<< 0 /*function call*/ << NumArgs << TheCall->getNumArgs()
<< SourceRange(TheCall->getArg(NumArgs)->getLocStart(),
(*(TheCall->arg_end()-1))->getLocEnd());
Expr *OrigArg = TheCall->getArg(NumArgs-1);
if (OrigArg->isTypeDependent())
return false;
// This operation requires a non-_Complex floating-point number.
if (!OrigArg->getType()->isRealFloatingType())
return Diag(OrigArg->getLocStart(),
diag::err_typecheck_call_invalid_unary_fp)
<< OrigArg->getType() << OrigArg->getSourceRange();
// If this is an implicit conversion from float -> double, remove it.
if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
Expr *CastArg = Cast->getSubExpr();
if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
"promotion from float to double is the only expected cast here");
Cast->setSubExpr(nullptr);
TheCall->setArg(NumArgs-1, CastArg);
}
}
return false;
}
/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
// This is declared to take (...), so we have to check everything.
ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
if (TheCall->getNumArgs() < 2)
return ExprError(Diag(TheCall->getLocEnd(),
diag::err_typecheck_call_too_few_args_at_least)
<< 0 /*function call*/ << 2 << TheCall->getNumArgs()
<< TheCall->getSourceRange());
// Determine which of the following types of shufflevector we're checking:
// 1) unary, vector mask: (lhs, mask)
// 2) binary, vector mask: (lhs, rhs, mask)
// 3) binary, scalar mask: (lhs, rhs, index, ..., index)
QualType resType = TheCall->getArg(0)->getType();
unsigned numElements = 0;
if (!TheCall->getArg(0)->isTypeDependent() &&
!TheCall->getArg(1)->isTypeDependent()) {
QualType LHSType = TheCall->getArg(0)->getType();
QualType RHSType = TheCall->getArg(1)->getType();
if (!LHSType->isVectorType() || !RHSType->isVectorType())
return ExprError(Diag(TheCall->getLocStart(),
diag::err_shufflevector_non_vector)
<< SourceRange(TheCall->getArg(0)->getLocStart(),
TheCall->getArg(1)->getLocEnd()));
numElements = LHSType->getAs<VectorType>()->getNumElements();
unsigned numResElements = TheCall->getNumArgs() - 2;
// Check to see if we have a call with 2 vector arguments, the unary shuffle
// with mask. If so, verify that RHS is an integer vector type with the
// same number of elts as lhs.
if (TheCall->getNumArgs() == 2) {
if (!RHSType->hasIntegerRepresentation() ||
RHSType->getAs<VectorType>()->getNumElements() != numElements)
return ExprError(Diag(TheCall->getLocStart(),
diag::err_shufflevector_incompatible_vector)
<< SourceRange(TheCall->getArg(1)->getLocStart(),
TheCall->getArg(1)->getLocEnd()));
} else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) {
return ExprError(Diag(TheCall->getLocStart(),
diag::err_shufflevector_incompatible_vector)
<< SourceRange(TheCall->getArg(0)->getLocStart(),
TheCall->getArg(1)->getLocEnd()));
} else if (numElements != numResElements) {
QualType eltType = LHSType->getAs<VectorType>()->getElementType();
resType = Context.getVectorType(eltType, numResElements,
VectorType::GenericVector);
}
}
for (unsigned i = 2; i < TheCall->getNumArgs(); i++) {
if (TheCall->getArg(i)->isTypeDependent() ||
TheCall->getArg(i)->isValueDependent())
continue;
llvm::APSInt Result(32);
if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
return ExprError(Diag(TheCall->getLocStart(),
diag::err_shufflevector_nonconstant_argument)
<< TheCall->getArg(i)->getSourceRange());
// Allow -1 which will be translated to undef in the IR.
if (Result.isSigned() && Result.isAllOnesValue())
continue;
if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
return ExprError(Diag(TheCall->getLocStart(),
diag::err_shufflevector_argument_too_large)
<< TheCall->getArg(i)->getSourceRange());
}
SmallVector<Expr*, 32> exprs;
for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) {
exprs.push_back(TheCall->getArg(i));
TheCall->setArg(i, nullptr);
}
return new (Context) ShuffleVectorExpr(Context, exprs, resType,
TheCall->getCallee()->getLocStart(),
TheCall->getRParenLoc());
}
/// SemaConvertVectorExpr - Handle __builtin_convertvector
ExprResult Sema::SemaConvertVectorExpr(Expr *E, TypeSourceInfo *TInfo,
SourceLocation BuiltinLoc,
SourceLocation RParenLoc) {
ExprValueKind VK = VK_RValue;
ExprObjectKind OK = OK_Ordinary;
QualType DstTy = TInfo->getType();
QualType SrcTy = E->getType();
if (!SrcTy->isVectorType() && !SrcTy->isDependentType())
return ExprError(Diag(BuiltinLoc,
diag::err_convertvector_non_vector)
<< E->getSourceRange());
if (!DstTy->isVectorType() && !DstTy->isDependentType())
return ExprError(Diag(BuiltinLoc,
diag::err_convertvector_non_vector_type));
if (!SrcTy->isDependentType() && !DstTy->isDependentType()) {
unsigned SrcElts = SrcTy->getAs<VectorType>()->getNumElements();
unsigned DstElts = DstTy->getAs<VectorType>()->getNumElements();
if (SrcElts != DstElts)
return ExprError(Diag(BuiltinLoc,
diag::err_convertvector_incompatible_vector)
<< E->getSourceRange());
}
return new (Context)
ConvertVectorExpr(E, TInfo, DstTy, VK, OK, BuiltinLoc, RParenLoc);
}
/// SemaBuiltinPrefetch - Handle __builtin_prefetch.
// This is declared to take (const void*, ...) and can take two
// optional constant int args.
bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) {
unsigned NumArgs = TheCall->getNumArgs();
if (NumArgs > 3)
return Diag(TheCall->getLocEnd(),
diag::err_typecheck_call_too_many_args_at_most)
<< 0 /*function call*/ << 3 << NumArgs
<< TheCall->getSourceRange();
// Argument 0 is checked for us and the remaining arguments must be
// constant integers.
for (unsigned i = 1; i != NumArgs; ++i)
if (SemaBuiltinConstantArgRange(TheCall, i, 0, i == 1 ? 1 : 3))
return true;
return false;
}
/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
/// TheCall is a constant expression.
bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
llvm::APSInt &Result) {
Expr *Arg = TheCall->getArg(ArgNum);
DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
if (Arg->isTypeDependent() || Arg->isValueDependent()) return false;
if (!Arg->isIntegerConstantExpr(Result, Context))
return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type)
<< FDecl->getDeclName() << Arg->getSourceRange();
return false;
}
/// SemaBuiltinConstantArgRange - Handle a check if argument ArgNum of CallExpr
/// TheCall is a constant expression in the range [Low, High].
bool Sema::SemaBuiltinConstantArgRange(CallExpr *TheCall, int ArgNum,
int Low, int High) {
llvm::APSInt Result;
// We can't check the value of a dependent argument.
Expr *Arg = TheCall->getArg(ArgNum);
if (Arg->isTypeDependent() || Arg->isValueDependent())
return false;
// Check constant-ness first.
if (SemaBuiltinConstantArg(TheCall, ArgNum, Result))
return true;
if (Result.getSExtValue() < Low || Result.getSExtValue() > High)
return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
<< Low << High << Arg->getSourceRange();
return false;
}
/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val).
/// This checks that val is a constant 1.
bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
Expr *Arg = TheCall->getArg(1);
llvm::APSInt Result;
// TODO: This is less than ideal. Overload this to take a value.
if (SemaBuiltinConstantArg(TheCall, 1, Result))
return true;
if (Result != 1)
return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
<< SourceRange(Arg->getLocStart(), Arg->getLocEnd());
return false;
}
namespace {
enum StringLiteralCheckType {
SLCT_NotALiteral,
SLCT_UncheckedLiteral,
SLCT_CheckedLiteral
};
}
// Determine if an expression is a string literal or constant string.
// If this function returns false on the arguments to a function expecting a
// format string, we will usually need to emit a warning.
// True string literals are then checked by CheckFormatString.
static StringLiteralCheckType
checkFormatStringExpr(Sema &S, const Expr *E, ArrayRef<const Expr *> Args,
bool HasVAListArg, unsigned format_idx,
unsigned firstDataArg, Sema::FormatStringType Type,
Sema::VariadicCallType CallType, bool InFunctionCall,
llvm::SmallBitVector &CheckedVarArgs) {
tryAgain:
if (E->isTypeDependent() || E->isValueDependent())
return SLCT_NotALiteral;
E = E->IgnoreParenCasts();
if (E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull))
// Technically -Wformat-nonliteral does not warn about this case.
// The behavior of printf and friends in this case is implementation
// dependent. Ideally if the format string cannot be null then
// it should have a 'nonnull' attribute in the function prototype.
return SLCT_UncheckedLiteral;
switch (E->getStmtClass()) {
case Stmt::BinaryConditionalOperatorClass:
case Stmt::ConditionalOperatorClass: {
// The expression is a literal if both sub-expressions were, and it was
// completely checked only if both sub-expressions were checked.
const AbstractConditionalOperator *C =
cast<AbstractConditionalOperator>(E);
StringLiteralCheckType Left =
checkFormatStringExpr(S, C->getTrueExpr(), Args,
HasVAListArg, format_idx, firstDataArg,
Type, CallType, InFunctionCall, CheckedVarArgs);
if (Left == SLCT_NotALiteral)
return SLCT_NotALiteral;
StringLiteralCheckType Right =
checkFormatStringExpr(S, C->getFalseExpr(), Args,
HasVAListArg, format_idx, firstDataArg,
Type, CallType, InFunctionCall, CheckedVarArgs);
return Left < Right ? Left : Right;
}
case Stmt::ImplicitCastExprClass: {
E = cast<ImplicitCastExpr>(E)->getSubExpr();
goto tryAgain;
}
case Stmt::OpaqueValueExprClass:
if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) {
E = src;
goto tryAgain;
}
return SLCT_NotALiteral;
case Stmt::PredefinedExprClass:
// While __func__, etc., are technically not string literals, they
// cannot contain format specifiers and thus are not a security
// liability.
return SLCT_UncheckedLiteral;
case Stmt::DeclRefExprClass: {
const DeclRefExpr *DR = cast<DeclRefExpr>(E);
// As an exception, do not flag errors for variables binding to
// const string literals.
if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
bool isConstant = false;
QualType T = DR->getType();
if (const ArrayType *AT = S.Context.getAsArrayType(T)) {
isConstant = AT->getElementType().isConstant(S.Context);
} else if (const PointerType *PT = T->getAs<PointerType>()) {
isConstant = T.isConstant(S.Context) &&
PT->getPointeeType().isConstant(S.Context);
} else if (T->isObjCObjectPointerType()) {
// In ObjC, there is usually no "const ObjectPointer" type,
// so don't check if the pointee type is constant.
isConstant = T.isConstant(S.Context);
}
if (isConstant) {
if (const Expr *Init = VD->getAnyInitializer()) {
// Look through initializers like const char c[] = { "foo" }
if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) {
if (InitList->isStringLiteralInit())
Init = InitList->getInit(0)->IgnoreParenImpCasts();
}
return checkFormatStringExpr(S, Init, Args,
HasVAListArg, format_idx,
firstDataArg, Type, CallType,
/*InFunctionCall*/false, CheckedVarArgs);
}
}
// For vprintf* functions (i.e., HasVAListArg==true), we add a
// special check to see if the format string is a function parameter
// of the function calling the printf function. If the function
// has an attribute indicating it is a printf-like function, then we
// should suppress warnings concerning non-literals being used in a call
// to a vprintf function. For example:
//
// void
// logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){
// va_list ap;
// va_start(ap, fmt);
// vprintf(fmt, ap); // Do NOT emit a warning about "fmt".
// ...
// }
if (HasVAListArg) {
if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) {
if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) {
int PVIndex = PV->getFunctionScopeIndex() + 1;
for (const auto *PVFormat : ND->specific_attrs<FormatAttr>()) {
// adjust for implicit parameter
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
if (MD->isInstance())
++PVIndex;
// We also check if the formats are compatible.
// We can't pass a 'scanf' string to a 'printf' function.
if (PVIndex == PVFormat->getFormatIdx() &&
Type == S.GetFormatStringType(PVFormat))
return SLCT_UncheckedLiteral;
}
}
}
}
}
return SLCT_NotALiteral;
}
case Stmt::CallExprClass:
case Stmt::CXXMemberCallExprClass: {
const CallExpr *CE = cast<CallExpr>(E);
if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) {
unsigned ArgIndex = FA->getFormatIdx();
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
if (MD->isInstance())
--ArgIndex;
const Expr *Arg = CE->getArg(ArgIndex - 1);
return checkFormatStringExpr(S, Arg, Args,
HasVAListArg, format_idx, firstDataArg,
Type, CallType, InFunctionCall,
CheckedVarArgs);
} else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
unsigned BuiltinID = FD->getBuiltinID();
if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString ||
BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) {
const Expr *Arg = CE->getArg(0);
return checkFormatStringExpr(S, Arg, Args,
HasVAListArg, format_idx,
firstDataArg, Type, CallType,
InFunctionCall, CheckedVarArgs);
}
}
}
return SLCT_NotALiteral;
}
case Stmt::ObjCStringLiteralClass:
case Stmt::StringLiteralClass: {
const StringLiteral *StrE = nullptr;
if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E))
StrE = ObjCFExpr->getString();
else
StrE = cast<StringLiteral>(E);
if (StrE) {
S.CheckFormatString(StrE, E, Args, HasVAListArg, format_idx, firstDataArg,
Type, InFunctionCall, CallType, CheckedVarArgs);
return SLCT_CheckedLiteral;
}
return SLCT_NotALiteral;
}
default:
return SLCT_NotALiteral;
}
}
Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) {
return llvm::StringSwitch<FormatStringType>(Format->getType()->getName())
.Case("scanf", FST_Scanf)
.Cases("printf", "printf0", FST_Printf)
.Cases("NSString", "CFString", FST_NSString)
.Case("strftime", FST_Strftime)
.Case("strfmon", FST_Strfmon)
.Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf)
.Default(FST_Unknown);
}
/// CheckFormatArguments - Check calls to printf and scanf (and similar
/// functions) for correct use of format strings.
/// Returns true if a format string has been fully checked.
bool Sema::CheckFormatArguments(const FormatAttr *Format,
ArrayRef<const Expr *> Args,
bool IsCXXMember,
VariadicCallType CallType,
SourceLocation Loc, SourceRange Range,
llvm::SmallBitVector &CheckedVarArgs) {
FormatStringInfo FSI;
if (getFormatStringInfo(Format, IsCXXMember, &FSI))
return CheckFormatArguments(Args, FSI.HasVAListArg, FSI.FormatIdx,
FSI.FirstDataArg, GetFormatStringType(Format),
CallType, Loc, Range, CheckedVarArgs);
return false;
}
bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args,
bool HasVAListArg, unsigned format_idx,
unsigned firstDataArg, FormatStringType Type,
VariadicCallType CallType,
SourceLocation Loc, SourceRange Range,
llvm::SmallBitVector &CheckedVarArgs) {
// CHECK: printf/scanf-like function is called with no format string.
if (format_idx >= Args.size()) {
Diag(Loc, diag::warn_missing_format_string) << Range;
return false;
}
const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts();
// CHECK: format string is not a string literal.
//
// Dynamically generated format strings are difficult to
// automatically vet at compile time. Requiring that format strings
// are string literals: (1) permits the checking of format strings by
// the compiler and thereby (2) can practically remove the source of
// many format string exploits.
// Format string can be either ObjC string (e.g. @"%d") or
// C string (e.g. "%d")
// ObjC string uses the same format specifiers as C string, so we can use
// the same format string checking logic for both ObjC and C strings.
StringLiteralCheckType CT =
checkFormatStringExpr(*this, OrigFormatExpr, Args, HasVAListArg,
format_idx, firstDataArg, Type, CallType,
/*IsFunctionCall*/true, CheckedVarArgs);
if (CT != SLCT_NotALiteral)
// Literal format string found, check done!
return CT == SLCT_CheckedLiteral;
// Strftime is particular as it always uses a single 'time' argument,
// so it is safe to pass a non-literal string.
if (Type == FST_Strftime)
return false;
// Do not emit diag when the string param is a macro expansion and the
// format is either NSString or CFString. This is a hack to prevent
// diag when using the NSLocalizedString and CFCopyLocalizedString macros
// which are usually used in place of NS and CF string literals.
if (Type == FST_NSString &&
SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart()))
return false;
// If there are no arguments specified, warn with -Wformat-security, otherwise
// warn only with -Wformat-nonliteral.
if (Args.size() == firstDataArg)
Diag(Args[format_idx]->getLocStart(),
diag::warn_format_nonliteral_noargs)
<< OrigFormatExpr->getSourceRange();
else
Diag(Args[format_idx]->getLocStart(),
diag::warn_format_nonliteral)
<< OrigFormatExpr->getSourceRange();
return false;
}
namespace {
class CheckFormatHandler : public analyze_format_string::FormatStringHandler {
protected:
Sema &S;
const StringLiteral *FExpr;
const Expr *OrigFormatExpr;
const unsigned FirstDataArg;
const unsigned NumDataArgs;
const char *Beg; // Start of format string.
const bool HasVAListArg;
ArrayRef<const Expr *> Args;
unsigned FormatIdx;
llvm::SmallBitVector CoveredArgs;
bool usesPositionalArgs;
bool atFirstArg;
bool inFunctionCall;
Sema::VariadicCallType CallType;
llvm::SmallBitVector &CheckedVarArgs;
public:
CheckFormatHandler(Sema &s, const StringLiteral *fexpr,
const Expr *origFormatExpr, unsigned firstDataArg,
unsigned numDataArgs, const char *beg, bool hasVAListArg,
ArrayRef<const Expr *> Args,
unsigned formatIdx, bool inFunctionCall,
Sema::VariadicCallType callType,
llvm::SmallBitVector &CheckedVarArgs)
: S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr),
FirstDataArg(firstDataArg), NumDataArgs(numDataArgs),
Beg(beg), HasVAListArg(hasVAListArg),
Args(Args), FormatIdx(formatIdx),
usesPositionalArgs(false), atFirstArg(true),
inFunctionCall(inFunctionCall), CallType(callType),
CheckedVarArgs(CheckedVarArgs) {
CoveredArgs.resize(numDataArgs);
CoveredArgs.reset();
}
void DoneProcessing();
void HandleIncompleteSpecifier(const char *startSpecifier,
unsigned specifierLen) override;
void HandleInvalidLengthModifier(
const analyze_format_string::FormatSpecifier &FS,
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen,
unsigned DiagID);
void HandleNonStandardLengthModifier(
const analyze_format_string::FormatSpecifier &FS,
const char *startSpecifier, unsigned specifierLen);
void HandleNonStandardConversionSpecifier(
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen);
void HandlePosition(const char *startPos, unsigned posLen) override;
void HandleInvalidPosition(const char *startSpecifier,
unsigned specifierLen,
analyze_format_string::PositionContext p) override;
void HandleZeroPosition(const char *startPos, unsigned posLen) override;
void HandleNullChar(const char *nullCharacter) override;
template <typename Range>
static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall,
const Expr *ArgumentExpr,
PartialDiagnostic PDiag,
SourceLocation StringLoc,
bool IsStringLocation, Range StringRange,
ArrayRef<FixItHint> Fixit = None);
protected:
bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc,
const char *startSpec,
unsigned specifierLen,
const char *csStart, unsigned csLen);
void HandlePositionalNonpositionalArgs(SourceLocation Loc,
const char *startSpec,
unsigned specifierLen);
SourceRange getFormatStringRange();
CharSourceRange getSpecifierRange(const char *startSpecifier,
unsigned specifierLen);
SourceLocation getLocationOfByte(const char *x);
const Expr *getDataArg(unsigned i) const;
bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS,
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen,
unsigned argIndex);
template <typename Range>
void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc,
bool IsStringLocation, Range StringRange,
ArrayRef<FixItHint> Fixit = None);
};
}
SourceRange CheckFormatHandler::getFormatStringRange() {
return OrigFormatExpr->getSourceRange();
}
CharSourceRange CheckFormatHandler::
getSpecifierRange(const char *startSpecifier, unsigned specifierLen) {
SourceLocation Start = getLocationOfByte(startSpecifier);
SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1);
// Advance the end SourceLocation by one due to half-open ranges.
End = End.getLocWithOffset(1);
return CharSourceRange::getCharRange(Start, End);
}
SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) {
return S.getLocationOfStringLiteralByte(FExpr, x - Beg);
}
void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier,
unsigned specifierLen){
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier),
getLocationOfByte(startSpecifier),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
}
void CheckFormatHandler::HandleInvalidLengthModifier(
const analyze_format_string::FormatSpecifier &FS,
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen, unsigned DiagID) {
using namespace analyze_format_string;
const LengthModifier &LM = FS.getLengthModifier();
CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
// See if we know how to fix this length modifier.
Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
if (FixedLM) {
EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
getLocationOfByte(LM.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
<< FixedLM->toString()
<< FixItHint::CreateReplacement(LMRange, FixedLM->toString());
} else {
FixItHint Hint;
if (DiagID == diag::warn_format_nonsensical_length)
Hint = FixItHint::CreateRemoval(LMRange);
EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
getLocationOfByte(LM.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen),
Hint);
}
}
void CheckFormatHandler::HandleNonStandardLengthModifier(
const analyze_format_string::FormatSpecifier &FS,
const char *startSpecifier, unsigned specifierLen) {
using namespace analyze_format_string;
const LengthModifier &LM = FS.getLengthModifier();
CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
// See if we know how to fix this length modifier.
Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
if (FixedLM) {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
<< LM.toString() << 0,
getLocationOfByte(LM.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
<< FixedLM->toString()
<< FixItHint::CreateReplacement(LMRange, FixedLM->toString());
} else {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
<< LM.toString() << 0,
getLocationOfByte(LM.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
}
}
void CheckFormatHandler::HandleNonStandardConversionSpecifier(
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen) {
using namespace analyze_format_string;
// See if we know how to fix this conversion specifier.
Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier();
if (FixedCS) {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
<< CS.toString() << /*conversion specifier*/1,
getLocationOfByte(CS.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength());
S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier)
<< FixedCS->toString()
<< FixItHint::CreateReplacement(CSRange, FixedCS->toString());
} else {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
<< CS.toString() << /*conversion specifier*/1,
getLocationOfByte(CS.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
}
}
void CheckFormatHandler::HandlePosition(const char *startPos,
unsigned posLen) {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg),
getLocationOfByte(startPos),
/*IsStringLocation*/true,
getSpecifierRange(startPos, posLen));
}
void
CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen,
analyze_format_string::PositionContext p) {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier)
<< (unsigned) p,
getLocationOfByte(startPos), /*IsStringLocation*/true,
getSpecifierRange(startPos, posLen));
}
void CheckFormatHandler::HandleZeroPosition(const char *startPos,
unsigned posLen) {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier),
getLocationOfByte(startPos),
/*IsStringLocation*/true,
getSpecifierRange(startPos, posLen));
}
void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {
if (!isa<ObjCStringLiteral>(OrigFormatExpr)) {
// The presence of a null character is likely an error.
EmitFormatDiagnostic(
S.PDiag(diag::warn_printf_format_string_contains_null_char),
getLocationOfByte(nullCharacter), /*IsStringLocation*/true,
getFormatStringRange());
}
}
// Note that this may return NULL if there was an error parsing or building
// one of the argument expressions.
const Expr *CheckFormatHandler::getDataArg(unsigned i) const {
return Args[FirstDataArg + i];
}
void CheckFormatHandler::DoneProcessing() {
// Does the number of data arguments exceed the number of
// format conversions in the format string?
if (!HasVAListArg) {
// Find any arguments that weren't covered.
CoveredArgs.flip();
signed notCoveredArg = CoveredArgs.find_first();
if (notCoveredArg >= 0) {
assert((unsigned)notCoveredArg < NumDataArgs);
if (const Expr *E = getDataArg((unsigned) notCoveredArg)) {
SourceLocation Loc = E->getLocStart();
if (!S.getSourceManager().isInSystemMacro(Loc)) {
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used),
Loc, /*IsStringLocation*/false,
getFormatStringRange());
}
}
}
}
}
bool
CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex,
SourceLocation Loc,
const char *startSpec,
unsigned specifierLen,
const char *csStart,
unsigned csLen) {
bool keepGoing = true;
if (argIndex < NumDataArgs) {
// Consider the argument coverered, even though the specifier doesn't
// make sense.
CoveredArgs.set(argIndex);
}
else {
// If argIndex exceeds the number of data arguments we
// don't issue a warning because that is just a cascade of warnings (and
// they may have intended '%%' anyway). We don't want to continue processing
// the format string after this point, however, as we will like just get
// gibberish when trying to match arguments.
keepGoing = false;
}
EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion)
<< StringRef(csStart, csLen),
Loc, /*IsStringLocation*/true,
getSpecifierRange(startSpec, specifierLen));
return keepGoing;
}
void
CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc,
const char *startSpec,
unsigned specifierLen) {
EmitFormatDiagnostic(
S.PDiag(diag::warn_format_mix_positional_nonpositional_args),
Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen));
}
bool
CheckFormatHandler::CheckNumArgs(
const analyze_format_string::FormatSpecifier &FS,
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen, unsigned argIndex) {
if (argIndex >= NumDataArgs) {
PartialDiagnostic PDiag = FS.usesPositionalArg()
? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args)
<< (argIndex+1) << NumDataArgs)
: S.PDiag(diag::warn_printf_insufficient_data_args);
EmitFormatDiagnostic(
PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
return false;
}
return true;
}
template<typename Range>
void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag,
SourceLocation Loc,
bool IsStringLocation,
Range StringRange,
ArrayRef<FixItHint> FixIt) {
EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag,
Loc, IsStringLocation, StringRange, FixIt);
}
/// \brief If the format string is not within the funcion call, emit a note
/// so that the function call and string are in diagnostic messages.
///
/// \param InFunctionCall if true, the format string is within the function
/// call and only one diagnostic message will be produced. Otherwise, an
/// extra note will be emitted pointing to location of the format string.
///
/// \param ArgumentExpr the expression that is passed as the format string
/// argument in the function call. Used for getting locations when two
/// diagnostics are emitted.
///
/// \param PDiag the callee should already have provided any strings for the
/// diagnostic message. This function only adds locations and fixits
/// to diagnostics.
///
/// \param Loc primary location for diagnostic. If two diagnostics are
/// required, one will be at Loc and a new SourceLocation will be created for
/// the other one.
///
/// \param IsStringLocation if true, Loc points to the format string should be
/// used for the note. Otherwise, Loc points to the argument list and will
/// be used with PDiag.
///
/// \param StringRange some or all of the string to highlight. This is
/// templated so it can accept either a CharSourceRange or a SourceRange.
///
/// \param FixIt optional fix it hint for the format string.
template<typename Range>
void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall,
const Expr *ArgumentExpr,
PartialDiagnostic PDiag,
SourceLocation Loc,
bool IsStringLocation,
Range StringRange,
ArrayRef<FixItHint> FixIt) {
if (InFunctionCall) {
const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag);
D << StringRange;
for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end();
I != E; ++I) {
D << *I;
}
} else {
S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag)
<< ArgumentExpr->getSourceRange();
const Sema::SemaDiagnosticBuilder &Note =
S.Diag(IsStringLocation ? Loc : StringRange.getBegin(),
diag::note_format_string_defined);
Note << StringRange;
for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end();
I != E; ++I) {
Note << *I;
}
}
}
//===--- CHECK: Printf format string checking ------------------------------===//
namespace {
class CheckPrintfHandler : public CheckFormatHandler {
bool ObjCContext;
public:
CheckPrintfHandler(Sema &s, const StringLiteral *fexpr,
const Expr *origFormatExpr, unsigned firstDataArg,
unsigned numDataArgs, bool isObjC,
const char *beg, bool hasVAListArg,
ArrayRef<const Expr *> Args,
unsigned formatIdx, bool inFunctionCall,
Sema::VariadicCallType CallType,
llvm::SmallBitVector &CheckedVarArgs)
: CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
numDataArgs, beg, hasVAListArg, Args,
formatIdx, inFunctionCall, CallType, CheckedVarArgs),
ObjCContext(isObjC)
{}
bool HandleInvalidPrintfConversionSpecifier(
const analyze_printf::PrintfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen) override;
bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen) override;
bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
const char *StartSpecifier,
unsigned SpecifierLen,
const Expr *E);
bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k,
const char *startSpecifier, unsigned specifierLen);
void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalAmount &Amt,
unsigned type,
const char *startSpecifier, unsigned specifierLen);
void HandleFlag(const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalFlag &flag,
const char *startSpecifier, unsigned specifierLen);
void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalFlag &ignoredFlag,
const analyze_printf::OptionalFlag &flag,
const char *startSpecifier, unsigned specifierLen);
bool checkForCStrMembers(const analyze_printf::ArgType &AT,
const Expr *E);
};
}
bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier(
const analyze_printf::PrintfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen) {
const analyze_printf::PrintfConversionSpecifier &CS =
FS.getConversionSpecifier();
return HandleInvalidConversionSpecifier(FS.getArgIndex(),
getLocationOfByte(CS.getStart()),
startSpecifier, specifierLen,
CS.getStart(), CS.getLength());
}
bool CheckPrintfHandler::HandleAmount(
const analyze_format_string::OptionalAmount &Amt,
unsigned k, const char *startSpecifier,
unsigned specifierLen) {
if (Amt.hasDataArgument()) {
if (!HasVAListArg) {
unsigned argIndex = Amt.getArgIndex();
if (argIndex >= NumDataArgs) {
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg)
<< k,
getLocationOfByte(Amt.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
// Don't do any more checking. We will just emit
// spurious errors.
return false;
}
// Type check the data argument. It should be an 'int'.
// Although not in conformance with C99, we also allow the argument to be
// an 'unsigned int' as that is a reasonably safe case. GCC also
// doesn't emit a warning for that case.
CoveredArgs.set(argIndex);
const Expr *Arg = getDataArg(argIndex);
if (!Arg)
return false;
QualType T = Arg->getType();
const analyze_printf::ArgType &AT = Amt.getArgType(S.Context);
assert(AT.isValid());
if (!AT.matchesType(S.Context, T)) {
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type)
<< k << AT.getRepresentativeTypeName(S.Context)
<< T << Arg->getSourceRange(),
getLocationOfByte(Amt.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
// Don't do any more checking. We will just emit
// spurious errors.
return false;
}
}
}
return true;
}
void CheckPrintfHandler::HandleInvalidAmount(
const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalAmount &Amt,
unsigned type,
const char *startSpecifier,
unsigned specifierLen) {
const analyze_printf::PrintfConversionSpecifier &CS =
FS.getConversionSpecifier();
FixItHint fixit =
Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant
? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(),
Amt.getConstantLength()))
: FixItHint();
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount)
<< type << CS.toString(),
getLocationOfByte(Amt.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen),
fixit);
}
void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalFlag &flag,
const char *startSpecifier,
unsigned specifierLen) {
// Warn about pointless flag with a fixit removal.
const analyze_printf::PrintfConversionSpecifier &CS =
FS.getConversionSpecifier();
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag)
<< flag.toString() << CS.toString(),
getLocationOfByte(flag.getPosition()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen),
FixItHint::CreateRemoval(
getSpecifierRange(flag.getPosition(), 1)));
}
void CheckPrintfHandler::HandleIgnoredFlag(
const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalFlag &ignoredFlag,
const analyze_printf::OptionalFlag &flag,
const char *startSpecifier,
unsigned specifierLen) {
// Warn about ignored flag with a fixit removal.
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag)
<< ignoredFlag.toString() << flag.toString(),
getLocationOfByte(ignoredFlag.getPosition()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen),
FixItHint::CreateRemoval(
getSpecifierRange(ignoredFlag.getPosition(), 1)));
}
// Determines if the specified is a C++ class or struct containing
// a member with the specified name and kind (e.g. a CXXMethodDecl named
// "c_str()").
template<typename MemberKind>
static llvm::SmallPtrSet<MemberKind*, 1>
CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) {
const RecordType *RT = Ty->getAs<RecordType>();
llvm::SmallPtrSet<MemberKind*, 1> Results;
if (!RT)
return Results;
const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
if (!RD || !RD->getDefinition())
return Results;
LookupResult R(S, &S.Context.Idents.get(Name), SourceLocation(),
Sema::LookupMemberName);
R.suppressDiagnostics();
// We just need to include all members of the right kind turned up by the
// filter, at this point.
if (S.LookupQualifiedName(R, RT->getDecl()))
for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
NamedDecl *decl = (*I)->getUnderlyingDecl();
if (MemberKind *FK = dyn_cast<MemberKind>(decl))
Results.insert(FK);
}
return Results;
}
/// Check if we could call '.c_str()' on an object.
///
/// FIXME: This returns the wrong results in some cases (if cv-qualifiers don't
/// allow the call, or if it would be ambiguous).
bool Sema::hasCStrMethod(const Expr *E) {
typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet;
MethodSet Results =
CXXRecordMembersNamed<CXXMethodDecl>("c_str", *this, E->getType());
for (MethodSet::iterator MI = Results.begin(), ME = Results.end();
MI != ME; ++MI)
if ((*MI)->getMinRequiredArguments() == 0)
return true;
return false;
}
// Check if a (w)string was passed when a (w)char* was needed, and offer a
// better diagnostic if so. AT is assumed to be valid.
// Returns true when a c_str() conversion method is found.
bool CheckPrintfHandler::checkForCStrMembers(
const analyze_printf::ArgType &AT, const Expr *E) {
typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet;
MethodSet Results =
CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType());
for (MethodSet::iterator MI = Results.begin(), ME = Results.end();
MI != ME; ++MI) {
const CXXMethodDecl *Method = *MI;
if (Method->getMinRequiredArguments() == 0 &&
AT.matchesType(S.Context, Method->getReturnType())) {
// FIXME: Suggest parens if the expression needs them.
SourceLocation EndLoc = S.getLocForEndOfToken(E->getLocEnd());
S.Diag(E->getLocStart(), diag::note_printf_c_str)
<< "c_str()"
<< FixItHint::CreateInsertion(EndLoc, ".c_str()");
return true;
}
}
return false;
}
bool
CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier
&FS,
const char *startSpecifier,
unsigned specifierLen) {
using namespace analyze_format_string;
using namespace analyze_printf;
const PrintfConversionSpecifier &CS = FS.getConversionSpecifier();
if (FS.consumesDataArgument()) {
if (atFirstArg) {
atFirstArg = false;
usesPositionalArgs = FS.usesPositionalArg();
}
else if (usesPositionalArgs != FS.usesPositionalArg()) {
HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
startSpecifier, specifierLen);
return false;
}
}
// First check if the field width, precision, and conversion specifier
// have matching data arguments.
if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0,
startSpecifier, specifierLen)) {
return false;
}
if (!HandleAmount(FS.getPrecision(), /* precision */ 1,
startSpecifier, specifierLen)) {
return false;
}
if (!CS.consumesDataArgument()) {
// FIXME: Technically specifying a precision or field width here
// makes no sense. Worth issuing a warning at some point.
return true;
}
// Consume the argument.
unsigned argIndex = FS.getArgIndex();
if (argIndex < NumDataArgs) {
// The check to see if the argIndex is valid will come later.
// We set the bit here because we may exit early from this
// function if we encounter some other error.
CoveredArgs.set(argIndex);
}
// Check for using an Objective-C specific conversion specifier
// in a non-ObjC literal.
if (!ObjCContext && CS.isObjCArg()) {
return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier,
specifierLen);
}
// Check for invalid use of field width
if (!FS.hasValidFieldWidth()) {
HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0,
startSpecifier, specifierLen);
}
// Check for invalid use of precision
if (!FS.hasValidPrecision()) {
HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1,
startSpecifier, specifierLen);
}
// Check each flag does not conflict with any other component.
if (!FS.hasValidThousandsGroupingPrefix())
HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen);
if (!FS.hasValidLeadingZeros())
HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen);
if (!FS.hasValidPlusPrefix())
HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen);
if (!FS.hasValidSpacePrefix())
HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen);
if (!FS.hasValidAlternativeForm())
HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen);
if (!FS.hasValidLeftJustified())
HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen);
// Check that flags are not ignored by another flag
if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+'
HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(),
startSpecifier, specifierLen);
if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-'
HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(),
startSpecifier, specifierLen);
// Check the length modifier is valid with the given conversion specifier.
if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
diag::warn_format_nonsensical_length);
else if (!FS.hasStandardLengthModifier())
HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
else if (!FS.hasStandardLengthConversionCombination())
HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
diag::warn_format_non_standard_conversion_spec);
if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
// The remaining checks depend on the data arguments.
if (HasVAListArg)
return true;
if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
return false;
const Expr *Arg = getDataArg(argIndex);
if (!Arg)
return true;
return checkFormatExpr(FS, startSpecifier, specifierLen, Arg);
}
static bool requiresParensToAddCast(const Expr *E) {
// FIXME: We should have a general way to reason about operator
// precedence and whether parens are actually needed here.
// Take care of a few common cases where they aren't.
const Expr *Inside = E->IgnoreImpCasts();
if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside))
Inside = POE->getSyntacticForm()->IgnoreImpCasts();
switch (Inside->getStmtClass()) {
case Stmt::ArraySubscriptExprClass:
case Stmt::CallExprClass:
case Stmt::CharacterLiteralClass:
case Stmt::CXXBoolLiteralExprClass:
case Stmt::DeclRefExprClass:
case Stmt::FloatingLiteralClass:
case Stmt::IntegerLiteralClass:
case Stmt::MemberExprClass:
case Stmt::ObjCArrayLiteralClass:
case Stmt::ObjCBoolLiteralExprClass:
case Stmt::ObjCBoxedExprClass:
case Stmt::ObjCDictionaryLiteralClass:
case Stmt::ObjCEncodeExprClass:
case Stmt::ObjCIvarRefExprClass:
case Stmt::ObjCMessageExprClass:
case Stmt::ObjCPropertyRefExprClass:
case Stmt::ObjCStringLiteralClass:
case Stmt::ObjCSubscriptRefExprClass:
case Stmt::ParenExprClass:
case Stmt::StringLiteralClass:
case Stmt::UnaryOperatorClass:
return false;
default:
return true;
}
}
bool
CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
const char *StartSpecifier,
unsigned SpecifierLen,
const Expr *E) {
using namespace analyze_format_string;
using namespace analyze_printf;
// Now type check the data expression that matches the
// format specifier.
const analyze_printf::ArgType &AT = FS.getArgType(S.Context,
ObjCContext);
if (!AT.isValid())
return true;
QualType ExprTy = E->getType();
while (const TypeOfExprType *TET = dyn_cast<TypeOfExprType>(ExprTy)) {
ExprTy = TET->getUnderlyingExpr()->getType();
}
if (AT.matchesType(S.Context, ExprTy))
return true;
// Look through argument promotions for our error message's reported type.
// This includes the integral and floating promotions, but excludes array
// and function pointer decay; seeing that an argument intended to be a
// string has type 'char [6]' is probably more confusing than 'char *'.
if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
if (ICE->getCastKind() == CK_IntegralCast ||
ICE->getCastKind() == CK_FloatingCast) {
E = ICE->getSubExpr();
ExprTy = E->getType();
// Check if we didn't match because of an implicit cast from a 'char'
// or 'short' to an 'int'. This is done because printf is a varargs
// function.
if (ICE->getType() == S.Context.IntTy ||
ICE->getType() == S.Context.UnsignedIntTy) {
// All further checking is done on the subexpression.
if (AT.matchesType(S.Context, ExprTy))
return true;
}
}
} else if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) {
// Special case for 'a', which has type 'int' in C.
// Note, however, that we do /not/ want to treat multibyte constants like
// 'MooV' as characters! This form is deprecated but still exists.
if (ExprTy == S.Context.IntTy)
if (llvm::isUIntN(S.Context.getCharWidth(), CL->getValue()))
ExprTy = S.Context.CharTy;
}
// Look through enums to their underlying type.
bool IsEnum = false;
if (auto EnumTy = ExprTy->getAs<EnumType>()) {
ExprTy = EnumTy->getDecl()->getIntegerType();
IsEnum = true;
}
// %C in an Objective-C context prints a unichar, not a wchar_t.
// If the argument is an integer of some kind, believe the %C and suggest
// a cast instead of changing the conversion specifier.
QualType IntendedTy = ExprTy;
if (ObjCContext &&
FS.getConversionSpecifier().getKind() == ConversionSpecifier::CArg) {
if (ExprTy->isIntegralOrUnscopedEnumerationType() &&
!ExprTy->isCharType()) {
// 'unichar' is defined as a typedef of unsigned short, but we should
// prefer using the typedef if it is visible.
IntendedTy = S.Context.UnsignedShortTy;
// While we are here, check if the value is an IntegerLiteral that happens
// to be within the valid range.
if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E)) {
const llvm::APInt &V = IL->getValue();
if (V.getActiveBits() <= S.Context.getTypeSize(IntendedTy))
return true;
}
LookupResult Result(S, &S.Context.Idents.get("unichar"), E->getLocStart(),
Sema::LookupOrdinaryName);
if (S.LookupName(Result, S.getCurScope())) {
NamedDecl *ND = Result.getFoundDecl();
if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(ND))
if (TD->getUnderlyingType() == IntendedTy)
IntendedTy = S.Context.getTypedefType(TD);
}
}
}
// Special-case some of Darwin's platform-independence types by suggesting
// casts to primitive types that are known to be large enough.
bool ShouldNotPrintDirectly = false;
if (S.Context.getTargetInfo().getTriple().isOSDarwin()) {
// Use a 'while' to peel off layers of typedefs.
QualType TyTy = IntendedTy;
while (const TypedefType *UserTy = TyTy->getAs<TypedefType>()) {
StringRef Name = UserTy->getDecl()->getName();
QualType CastTy = llvm::StringSwitch<QualType>(Name)
.Case("NSInteger", S.Context.LongTy)
.Case("NSUInteger", S.Context.UnsignedLongTy)
.Case("SInt32", S.Context.IntTy)
.Case("UInt32", S.Context.UnsignedIntTy)
.Default(QualType());
if (!CastTy.isNull()) {
ShouldNotPrintDirectly = true;
IntendedTy = CastTy;
break;
}
TyTy = UserTy->desugar();
}
}
// We may be able to offer a FixItHint if it is a supported type.
PrintfSpecifier fixedFS = FS;
bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(),
S.Context, ObjCContext);
if (success) {
// Get the fix string from the fixed format specifier
SmallString<16> buf;
llvm::raw_svector_ostream os(buf);
fixedFS.toString(os);
CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen);
if (IntendedTy == ExprTy) {
// In this case, the specifier is wrong and should be changed to match
// the argument.
EmitFormatDiagnostic(
S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
<< AT.getRepresentativeTypeName(S.Context) << IntendedTy << IsEnum
<< E->getSourceRange(),
E->getLocStart(),
/*IsStringLocation*/false,
SpecRange,
FixItHint::CreateReplacement(SpecRange, os.str()));
} else {
// The canonical type for formatting this value is different from the
// actual type of the expression. (This occurs, for example, with Darwin's
// NSInteger on 32-bit platforms, where it is typedef'd as 'int', but
// should be printed as 'long' for 64-bit compatibility.)
// Rather than emitting a normal format/argument mismatch, we want to
// add a cast to the recommended type (and correct the format string
// if necessary).
SmallString<16> CastBuf;
llvm::raw_svector_ostream CastFix(CastBuf);
CastFix << "(";
IntendedTy.print(CastFix, S.Context.getPrintingPolicy());
CastFix << ")";
SmallVector<FixItHint,4> Hints;
if (!AT.matchesType(S.Context, IntendedTy))
Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str()));
if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) {
// If there's already a cast present, just replace it.
SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc());
Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str()));
} else if (!requiresParensToAddCast(E)) {
// If the expression has high enough precedence,
// just write the C-style cast.
Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
CastFix.str()));
} else {
// Otherwise, add parens around the expression as well as the cast.
CastFix << "(";
Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
CastFix.str()));
SourceLocation After = S.getLocForEndOfToken(E->getLocEnd());
Hints.push_back(FixItHint::CreateInsertion(After, ")"));
}
if (ShouldNotPrintDirectly) {
// The expression has a type that should not be printed directly.
// We extract the name from the typedef because we don't want to show
// the underlying type in the diagnostic.
StringRef Name = cast<TypedefType>(ExprTy)->getDecl()->getName();
EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast)
<< Name << IntendedTy << IsEnum
<< E->getSourceRange(),
E->getLocStart(), /*IsStringLocation=*/false,
SpecRange, Hints);
} else {
// In this case, the expression could be printed using a different
// specifier, but we've decided that the specifier is probably correct
// and we should cast instead. Just use the normal warning message.
EmitFormatDiagnostic(
S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
<< AT.getRepresentativeTypeName(S.Context) << ExprTy << IsEnum
<< E->getSourceRange(),
E->getLocStart(), /*IsStringLocation*/false,
SpecRange, Hints);
}
}
} else {
const CharSourceRange &CSR = getSpecifierRange(StartSpecifier,
SpecifierLen);
// Since the warning for passing non-POD types to variadic functions
// was deferred until now, we emit a warning for non-POD
// arguments here.
switch (S.isValidVarArgType(ExprTy)) {
case Sema::VAK_Valid:
case Sema::VAK_ValidInCXX11:
EmitFormatDiagnostic(
S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
<< AT.getRepresentativeTypeName(S.Context) << ExprTy << IsEnum
<< CSR
<< E->getSourceRange(),
E->getLocStart(), /*IsStringLocation*/false, CSR);
break;
case Sema::VAK_Undefined:
EmitFormatDiagnostic(
S.PDiag(diag::warn_non_pod_vararg_with_format_string)
<< S.getLangOpts().CPlusPlus11
<< ExprTy
<< CallType
<< AT.getRepresentativeTypeName(S.Context)
<< CSR
<< E->getSourceRange(),
E->getLocStart(), /*IsStringLocation*/false, CSR);
checkForCStrMembers(AT, E);
break;
case Sema::VAK_Invalid:
if (ExprTy->isObjCObjectType())
EmitFormatDiagnostic(
S.PDiag(diag::err_cannot_pass_objc_interface_to_vararg_format)
<< S.getLangOpts().CPlusPlus11
<< ExprTy
<< CallType
<< AT.getRepresentativeTypeName(S.Context)
<< CSR
<< E->getSourceRange(),
E->getLocStart(), /*IsStringLocation*/false, CSR);
else
// FIXME: If this is an initializer list, suggest removing the braces
// or inserting a cast to the target type.
S.Diag(E->getLocStart(), diag::err_cannot_pass_to_vararg_format)
<< isa<InitListExpr>(E) << ExprTy << CallType
<< AT.getRepresentativeTypeName(S.Context)
<< E->getSourceRange();
break;
}
assert(FirstDataArg + FS.getArgIndex() < CheckedVarArgs.size() &&
"format string specifier index out of range");
CheckedVarArgs[FirstDataArg + FS.getArgIndex()] = true;
}
return true;
}
//===--- CHECK: Scanf format string checking ------------------------------===//
namespace {
class CheckScanfHandler : public CheckFormatHandler {
public:
CheckScanfHandler(Sema &s, const StringLiteral *fexpr,
const Expr *origFormatExpr, unsigned firstDataArg,
unsigned numDataArgs, const char *beg, bool hasVAListArg,
ArrayRef<const Expr *> Args,
unsigned formatIdx, bool inFunctionCall,
Sema::VariadicCallType CallType,
llvm::SmallBitVector &CheckedVarArgs)
: CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
numDataArgs, beg, hasVAListArg,
Args, formatIdx, inFunctionCall, CallType,
CheckedVarArgs)
{}
bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen) override;
bool HandleInvalidScanfConversionSpecifier(
const analyze_scanf::ScanfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen) override;
void HandleIncompleteScanList(const char *start, const char *end) override;
};
}
void CheckScanfHandler::HandleIncompleteScanList(const char *start,
const char *end) {
EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete),
getLocationOfByte(end), /*IsStringLocation*/true,
getSpecifierRange(start, end - start));
}
bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier(
const analyze_scanf::ScanfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen) {
const analyze_scanf::ScanfConversionSpecifier &CS =
FS.getConversionSpecifier();
return HandleInvalidConversionSpecifier(FS.getArgIndex(),
getLocationOfByte(CS.getStart()),
startSpecifier, specifierLen,
CS.getStart(), CS.getLength());
}
bool CheckScanfHandler::HandleScanfSpecifier(
const analyze_scanf::ScanfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen) {
using namespace analyze_scanf;
using namespace analyze_format_string;
const ScanfConversionSpecifier &CS = FS.getConversionSpecifier();
// Handle case where '%' and '*' don't consume an argument. These shouldn't
// be used to decide if we are using positional arguments consistently.
if (FS.consumesDataArgument()) {
if (atFirstArg) {
atFirstArg = false;
usesPositionalArgs = FS.usesPositionalArg();
}
else if (usesPositionalArgs != FS.usesPositionalArg()) {
HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
startSpecifier, specifierLen);
return false;
}
}
// Check if the field with is non-zero.
const OptionalAmount &Amt = FS.getFieldWidth();
if (Amt.getHowSpecified() == OptionalAmount::Constant) {
if (Amt.getConstantAmount() == 0) {
const CharSourceRange &R = getSpecifierRange(Amt.getStart(),
Amt.getConstantLength());
EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width),
getLocationOfByte(Amt.getStart()),
/*IsStringLocation*/true, R,
FixItHint::CreateRemoval(R));
}
}
if (!FS.consumesDataArgument()) {
// FIXME: Technically specifying a precision or field width here
// makes no sense. Worth issuing a warning at some point.
return true;
}
// Consume the argument.
unsigned argIndex = FS.getArgIndex();
if (argIndex < NumDataArgs) {
// The check to see if the argIndex is valid will come later.
// We set the bit here because we may exit early from this
// function if we encounter some other error.
CoveredArgs.set(argIndex);
}
// Check the length modifier is valid with the given conversion specifier.
if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
diag::warn_format_nonsensical_length);
else if (!FS.hasStandardLengthModifier())
HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
else if (!FS.hasStandardLengthConversionCombination())
HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
diag::warn_format_non_standard_conversion_spec);
if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
// The remaining checks depend on the data arguments.
if (HasVAListArg)
return true;
if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
return false;
// Check that the argument type matches the format specifier.
const Expr *Ex = getDataArg(argIndex);
if (!Ex)
return true;
const analyze_format_string::ArgType &AT = FS.getArgType(S.Context);
if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) {
ScanfSpecifier fixedFS = FS;
bool success = fixedFS.fixType(Ex->getType(),
Ex->IgnoreImpCasts()->getType(),
S.getLangOpts(), S.Context);
if (success) {
// Get the fix string from the fixed format specifier.
SmallString<128> buf;
llvm::raw_svector_ostream os(buf);
fixedFS.toString(os);
EmitFormatDiagnostic(
S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
<< AT.getRepresentativeTypeName(S.Context) << Ex->getType() << false
<< Ex->getSourceRange(),
Ex->getLocStart(),
/*IsStringLocation*/false,
getSpecifierRange(startSpecifier, specifierLen),
FixItHint::CreateReplacement(
getSpecifierRange(startSpecifier, specifierLen),
os.str()));
} else {
EmitFormatDiagnostic(
S.PDiag(diag::warn_format_conversion_argument_type_mismatch)
<< AT.getRepresentativeTypeName(S.Context) << Ex->getType() << false
<< Ex->getSourceRange(),
Ex->getLocStart(),
/*IsStringLocation*/false,
getSpecifierRange(startSpecifier, specifierLen));
}
}
return true;
}
void Sema::CheckFormatString(const StringLiteral *FExpr,
const Expr *OrigFormatExpr,
ArrayRef<const Expr *> Args,
bool HasVAListArg, unsigned format_idx,
unsigned firstDataArg, FormatStringType Type,
bool inFunctionCall, VariadicCallType CallType,
llvm::SmallBitVector &CheckedVarArgs) {
// CHECK: is the format string a wide literal?
if (!FExpr->isAscii() && !FExpr->isUTF8()) {
CheckFormatHandler::EmitFormatDiagnostic(
*this, inFunctionCall, Args[format_idx],
PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(),
/*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
return;
}
// Str - The format string. NOTE: this is NOT null-terminated!
StringRef StrRef = FExpr->getString();
const char *Str = StrRef.data();
// Account for cases where the string literal is truncated in a declaration.
const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType());
assert(T && "String literal not of constant array type!");
size_t TypeSize = T->getSize().getZExtValue();
size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size());
const unsigned numDataArgs = Args.size() - firstDataArg;
// Emit a warning if the string literal is truncated and does not contain an
// embedded null character.
if (TypeSize <= StrRef.size() &&
StrRef.substr(0, TypeSize).find('\0') == StringRef::npos) {
CheckFormatHandler::EmitFormatDiagnostic(
*this, inFunctionCall, Args[format_idx],
PDiag(diag::warn_printf_format_string_not_null_terminated),
FExpr->getLocStart(),
/*IsStringLocation=*/true, OrigFormatExpr->getSourceRange());
return;
}
// CHECK: empty format string?
if (StrLen == 0 && numDataArgs > 0) {
CheckFormatHandler::EmitFormatDiagnostic(
*this, inFunctionCall, Args[format_idx],
PDiag(diag::warn_empty_format_string), FExpr->getLocStart(),
/*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
return;
}
if (Type == FST_Printf || Type == FST_NSString) {
CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
numDataArgs, (Type == FST_NSString),
Str, HasVAListArg, Args, format_idx,
inFunctionCall, CallType, CheckedVarArgs);
if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen,
getLangOpts(),
Context.getTargetInfo()))
H.DoneProcessing();
} else if (Type == FST_Scanf) {
CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs,
Str, HasVAListArg, Args, format_idx,
inFunctionCall, CallType, CheckedVarArgs);
if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen,
getLangOpts(),
Context.getTargetInfo()))
H.DoneProcessing();
} // TODO: handle other formats
}
//===--- CHECK: Warn on use of wrong absolute value function. -------------===//
// Returns the related absolute value function that is larger, of 0 if one
// does not exist.
static unsigned getLargerAbsoluteValueFunction(unsigned AbsFunction) {
switch (AbsFunction) {
default:
return 0;
case Builtin::BI__builtin_abs:
return Builtin::BI__builtin_labs;
case Builtin::BI__builtin_labs:
return Builtin::BI__builtin_llabs;
case Builtin::BI__builtin_llabs:
return 0;
case Builtin::BI__builtin_fabsf:
return Builtin::BI__builtin_fabs;
case Builtin::BI__builtin_fabs:
return Builtin::BI__builtin_fabsl;
case Builtin::BI__builtin_fabsl:
return 0;
case Builtin::BI__builtin_cabsf:
return Builtin::BI__builtin_cabs;
case Builtin::BI__builtin_cabs:
return Builtin::BI__builtin_cabsl;
case Builtin::BI__builtin_cabsl:
return 0;
case Builtin::BIabs:
return Builtin::BIlabs;
case Builtin::BIlabs:
return Builtin::BIllabs;
case Builtin::BIllabs:
return 0;
case Builtin::BIfabsf:
return Builtin::BIfabs;
case Builtin::BIfabs:
return Builtin::BIfabsl;
case Builtin::BIfabsl:
return 0;
case Builtin::BIcabsf:
return Builtin::BIcabs;
case Builtin::BIcabs:
return Builtin::BIcabsl;
case Builtin::BIcabsl:
return 0;
}
}
// Returns the argument type of the absolute value function.
static QualType getAbsoluteValueArgumentType(ASTContext &Context,
unsigned AbsType) {
if (AbsType == 0)
return QualType();
ASTContext::GetBuiltinTypeError Error = ASTContext::GE_None;
QualType BuiltinType = Context.GetBuiltinType(AbsType, Error);
if (Error != ASTContext::GE_None)
return QualType();
const FunctionProtoType *FT = BuiltinType->getAs<FunctionProtoType>();
if (!FT)
return QualType();
if (FT->getNumParams() != 1)
return QualType();
return FT->getParamType(0);
}
// Returns the best absolute value function, or zero, based on type and
// current absolute value function.
static unsigned getBestAbsFunction(ASTContext &Context, QualType ArgType,
unsigned AbsFunctionKind) {
unsigned BestKind = 0;
uint64_t ArgSize = Context.getTypeSize(ArgType);
for (unsigned Kind = AbsFunctionKind; Kind != 0;
Kind = getLargerAbsoluteValueFunction(Kind)) {
QualType ParamType = getAbsoluteValueArgumentType(Context, Kind);
if (Context.getTypeSize(ParamType) >= ArgSize) {
if (BestKind == 0)
BestKind = Kind;
else if (Context.hasSameType(ParamType, ArgType)) {
BestKind = Kind;
break;
}
}
}
return BestKind;
}
enum AbsoluteValueKind {
AVK_Integer,
AVK_Floating,
AVK_Complex
};
static AbsoluteValueKind getAbsoluteValueKind(QualType T) {
if (T->isIntegralOrEnumerationType())
return AVK_Integer;
if (T->isRealFloatingType())
return AVK_Floating;
if (T->isAnyComplexType())
return AVK_Complex;
llvm_unreachable("Type not integer, floating, or complex");
}
// Changes the absolute value function to a different type. Preserves whether
// the function is a builtin.
static unsigned changeAbsFunction(unsigned AbsKind,
AbsoluteValueKind ValueKind) {
switch (ValueKind) {
case AVK_Integer:
switch (AbsKind) {
default:
return 0;
case Builtin::BI__builtin_fabsf:
case Builtin::BI__builtin_fabs:
case Builtin::BI__builtin_fabsl:
case Builtin::BI__builtin_cabsf:
case Builtin::BI__builtin_cabs:
case Builtin::BI__builtin_cabsl:
return Builtin::BI__builtin_abs;
case Builtin::BIfabsf:
case Builtin::BIfabs:
case Builtin::BIfabsl:
case Builtin::BIcabsf:
case Builtin::BIcabs:
case Builtin::BIcabsl:
return Builtin::BIabs;
}
case AVK_Floating:
switch (AbsKind) {
default:
return 0;
case Builtin::BI__builtin_abs:
case Builtin::BI__builtin_labs:
case Builtin::BI__builtin_llabs:
case Builtin::BI__builtin_cabsf:
case Builtin::BI__builtin_cabs:
case Builtin::BI__builtin_cabsl:
return Builtin::BI__builtin_fabsf;
case Builtin::BIabs:
case Builtin::BIlabs:
case Builtin::BIllabs:
case Builtin::BIcabsf:
case Builtin::BIcabs:
case Builtin::BIcabsl:
return Builtin::BIfabsf;
}
case AVK_Complex:
switch (AbsKind) {
default:
return 0;
case Builtin::BI__builtin_abs:
case Builtin::BI__builtin_labs:
case Builtin::BI__builtin_llabs:
case Builtin::BI__builtin_fabsf:
case Builtin::BI__builtin_fabs:
case Builtin::BI__builtin_fabsl:
return Builtin::BI__builtin_cabsf;
case Builtin::BIabs:
case Builtin::BIlabs:
case Builtin::BIllabs:
case Builtin::BIfabsf:
case Builtin::BIfabs:
case Builtin::BIfabsl:
return Builtin::BIcabsf;
}
}
llvm_unreachable("Unable to convert function");
}
static unsigned getAbsoluteValueFunctionKind(const FunctionDecl *FDecl) {
const IdentifierInfo *FnInfo = FDecl->getIdentifier();
if (!FnInfo)
return 0;
switch (FDecl->getBuiltinID()) {
default:
return 0;
case Builtin::BI__builtin_abs:
case Builtin::BI__builtin_fabs:
case Builtin::BI__builtin_fabsf:
case Builtin::BI__builtin_fabsl:
case Builtin::BI__builtin_labs:
case Builtin::BI__builtin_llabs:
case Builtin::BI__builtin_cabs:
case Builtin::BI__builtin_cabsf:
case Builtin::BI__builtin_cabsl:
case Builtin::BIabs:
case Builtin::BIlabs:
case Builtin::BIllabs:
case Builtin::BIfabs:
case Builtin::BIfabsf:
case Builtin::BIfabsl:
case Builtin::BIcabs:
case Builtin::BIcabsf:
case Builtin::BIcabsl:
return FDecl->getBuiltinID();
}
llvm_unreachable("Unknown Builtin type");
}
// If the replacement is valid, emit a note with replacement function.
// Additionally, suggest including the proper header if not already included.
static void emitReplacement(Sema &S, SourceLocation Loc, SourceRange Range,
unsigned AbsKind, QualType ArgType) {
bool EmitHeaderHint = true;
const char *HeaderName = nullptr;
const char *FunctionName = nullptr;
if (S.getLangOpts().CPlusPlus && !ArgType->isAnyComplexType()) {
FunctionName = "std::abs";
if (ArgType->isIntegralOrEnumerationType()) {
HeaderName = "cstdlib";
} else if (ArgType->isRealFloatingType()) {
HeaderName = "cmath";
} else {
llvm_unreachable("Invalid Type");
}
// Lookup all std::abs
if (NamespaceDecl *Std = S.getStdNamespace()) {
LookupResult R(S, &S.Context.Idents.get("abs"), Loc, Sema::LookupAnyName);
R.suppressDiagnostics();
S.LookupQualifiedName(R, Std);
for (const auto *I : R) {
const FunctionDecl *FDecl = nullptr;
if (const UsingShadowDecl *UsingD = dyn_cast<UsingShadowDecl>(I)) {
FDecl = dyn_cast<FunctionDecl>(UsingD->getTargetDecl());
} else {
FDecl = dyn_cast<FunctionDecl>(I);
}
if (!FDecl)
continue;
// Found std::abs(), check that they are the right ones.
if (FDecl->getNumParams() != 1)
continue;
// Check that the parameter type can handle the argument.
QualType ParamType = FDecl->getParamDecl(0)->getType();
if (getAbsoluteValueKind(ArgType) == getAbsoluteValueKind(ParamType) &&
S.Context.getTypeSize(ArgType) <=
S.Context.getTypeSize(ParamType)) {
// Found a function, don't need the header hint.
EmitHeaderHint = false;
break;
}
}
}
} else {
FunctionName = S.Context.BuiltinInfo.GetName(AbsKind);
HeaderName = S.Context.BuiltinInfo.getHeaderName(AbsKind);
if (HeaderName) {
DeclarationName DN(&S.Context.Idents.get(FunctionName));
LookupResult R(S, DN, Loc, Sema::LookupAnyName);
R.suppressDiagnostics();
S.LookupName(R, S.getCurScope());
if (R.isSingleResult()) {
FunctionDecl *FD = dyn_cast<FunctionDecl>(R.getFoundDecl());
if (FD && FD->getBuiltinID() == AbsKind) {
EmitHeaderHint = false;
} else {
return;
}
} else if (!R.empty()) {
return;
}
}
}
S.Diag(Loc, diag::note_replace_abs_function)
<< FunctionName << FixItHint::CreateReplacement(Range, FunctionName);
if (!HeaderName)
return;
if (!EmitHeaderHint)
return;
S.Diag(Loc, diag::note_please_include_header) << HeaderName << FunctionName;
}
static bool IsFunctionStdAbs(const FunctionDecl *FDecl) {
if (!FDecl)
return false;
if (!FDecl->getIdentifier() || !FDecl->getIdentifier()->isStr("abs"))
return false;
const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(FDecl->getDeclContext());
while (ND && ND->isInlineNamespace()) {
ND = dyn_cast<NamespaceDecl>(ND->getDeclContext());
}
if (!ND || !ND->getIdentifier() || !ND->getIdentifier()->isStr("std"))
return false;
if (!isa<TranslationUnitDecl>(ND->getDeclContext()))
return false;
return true;
}
// Warn when using the wrong abs() function.
void Sema::CheckAbsoluteValueFunction(const CallExpr *Call,
const FunctionDecl *FDecl,
IdentifierInfo *FnInfo) {
if (Call->getNumArgs() != 1)
return;
unsigned AbsKind = getAbsoluteValueFunctionKind(FDecl);
bool IsStdAbs = IsFunctionStdAbs(FDecl);
if (AbsKind == 0 && !IsStdAbs)
return;
QualType ArgType = Call->getArg(0)->IgnoreParenImpCasts()->getType();
QualType ParamType = Call->getArg(0)->getType();
// Unsigned types can not be negative. Suggest to drop the absolute value
// function.
if (ArgType->isUnsignedIntegerType()) {
const char *FunctionName =
IsStdAbs ? "std::abs" : Context.BuiltinInfo.GetName(AbsKind);
Diag(Call->getExprLoc(), diag::warn_unsigned_abs) << ArgType << ParamType;
Diag(Call->getExprLoc(), diag::note_remove_abs)
<< FunctionName
<< FixItHint::CreateRemoval(Call->getCallee()->getSourceRange());
return;
}
// std::abs has overloads which prevent most of the absolute value problems
// from occurring.
if (IsStdAbs)
return;
AbsoluteValueKind ArgValueKind = getAbsoluteValueKind(ArgType);
AbsoluteValueKind ParamValueKind = getAbsoluteValueKind(ParamType);
// The argument and parameter are the same kind. Check if they are the right
// size.
if (ArgValueKind == ParamValueKind) {
if (Context.getTypeSize(ArgType) <= Context.getTypeSize(ParamType))
return;
unsigned NewAbsKind = getBestAbsFunction(Context, ArgType, AbsKind);
Diag(Call->getExprLoc(), diag::warn_abs_too_small)
<< FDecl << ArgType << ParamType;
if (NewAbsKind == 0)
return;
emitReplacement(*this, Call->getExprLoc(),
Call->getCallee()->getSourceRange(), NewAbsKind, ArgType);
return;
}
// ArgValueKind != ParamValueKind
// The wrong type of absolute value function was used. Attempt to find the
// proper one.
unsigned NewAbsKind = changeAbsFunction(AbsKind, ArgValueKind);
NewAbsKind = getBestAbsFunction(Context, ArgType, NewAbsKind);
if (NewAbsKind == 0)
return;
Diag(Call->getExprLoc(), diag::warn_wrong_absolute_value_type)
<< FDecl << ParamValueKind << ArgValueKind;
emitReplacement(*this, Call->getExprLoc(),
Call->getCallee()->getSourceRange(), NewAbsKind, ArgType);
return;
}
//===--- CHECK: Standard memory functions ---------------------------------===//
/// \brief Takes the expression passed to the size_t parameter of functions
/// such as memcmp, strncat, etc and warns if it's a comparison.
///
/// This is to catch typos like `if (memcmp(&a, &b, sizeof(a) > 0))`.
static bool CheckMemorySizeofForComparison(Sema &S, const Expr *E,
IdentifierInfo *FnName,
SourceLocation FnLoc,
SourceLocation RParenLoc) {
const BinaryOperator *Size = dyn_cast<BinaryOperator>(E);
if (!Size)
return false;
// if E is binop and op is >, <, >=, <=, ==, &&, ||:
if (!Size->isComparisonOp() && !Size->isEqualityOp() && !Size->isLogicalOp())
return false;
SourceRange SizeRange = Size->getSourceRange();
S.Diag(Size->getOperatorLoc(), diag::warn_memsize_comparison)
<< SizeRange << FnName;
S.Diag(FnLoc, diag::note_memsize_comparison_paren)
<< FnName << FixItHint::CreateInsertion(
S.getLocForEndOfToken(Size->getLHS()->getLocEnd()), ")")
<< FixItHint::CreateRemoval(RParenLoc);
S.Diag(SizeRange.getBegin(), diag::note_memsize_comparison_cast_silence)
<< FixItHint::CreateInsertion(SizeRange.getBegin(), "(size_t)(")
<< FixItHint::CreateInsertion(S.getLocForEndOfToken(SizeRange.getEnd()),
")");
return true;
}
/// \brief Determine whether the given type is or contains a dynamic class type
/// (e.g., whether it has a vtable).
static const CXXRecordDecl *getContainedDynamicClass(QualType T,
bool &IsContained) {
// Look through array types while ignoring qualifiers.
const Type *Ty = T->getBaseElementTypeUnsafe();
IsContained = false;
const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
RD = RD ? RD->getDefinition() : nullptr;
if (!RD)
return nullptr;
if (RD->isDynamicClass())
return RD;
// Check all the fields. If any bases were dynamic, the class is dynamic.
// It's impossible for a class to transitively contain itself by value, so
// infinite recursion is impossible.
for (auto *FD : RD->fields()) {
bool SubContained;
if (const CXXRecordDecl *ContainedRD =
getContainedDynamicClass(FD->getType(), SubContained)) {
IsContained = true;
return ContainedRD;
}
}
return nullptr;
}
/// \brief If E is a sizeof expression, returns its argument expression,
/// otherwise returns NULL.
static const Expr *getSizeOfExprArg(const Expr* E) {
if (const UnaryExprOrTypeTraitExpr *SizeOf =
dyn_cast<UnaryExprOrTypeTraitExpr>(E))
if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType())
return SizeOf->getArgumentExpr()->IgnoreParenImpCasts();
return nullptr;
}
/// \brief If E is a sizeof expression, returns its argument type.
static QualType getSizeOfArgType(const Expr* E) {
if (const UnaryExprOrTypeTraitExpr *SizeOf =
dyn_cast<UnaryExprOrTypeTraitExpr>(E))
if (SizeOf->getKind() == clang::UETT_SizeOf)
return SizeOf->getTypeOfArgument();
return QualType();
}
/// \brief Check for dangerous or invalid arguments to memset().
///
/// This issues warnings on known problematic, dangerous or unspecified
/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp'
/// function calls.
///
/// \param Call The call expression to diagnose.
void Sema::CheckMemaccessArguments(const CallExpr *Call,
unsigned BId,
IdentifierInfo *FnName) {
assert(BId != 0);
// It is possible to have a non-standard definition of memset. Validate
// we have enough arguments, and if not, abort further checking.
unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3);
if (Call->getNumArgs() < ExpectedNumArgs)
return;
unsigned LastArg = (BId == Builtin::BImemset ||
BId == Builtin::BIstrndup ? 1 : 2);
unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2);
const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts();
if (CheckMemorySizeofForComparison(*this, LenExpr, FnName,
Call->getLocStart(), Call->getRParenLoc()))
return;
// We have special checking when the length is a sizeof expression.
QualType SizeOfArgTy = getSizeOfArgType(LenExpr);
const Expr *SizeOfArg = getSizeOfExprArg(LenExpr);
llvm::FoldingSetNodeID SizeOfArgID;
for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) {
const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts();
SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange();
QualType DestTy = Dest->getType();
if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) {
QualType PointeeTy = DestPtrTy->getPointeeType();
// Never warn about void type pointers. This can be used to suppress
// false positives.
if (PointeeTy->isVoidType())
continue;
// Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by
// actually comparing the expressions for equality. Because computing the
// expression IDs can be expensive, we only do this if the diagnostic is
// enabled.
if (SizeOfArg &&
!Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess,
SizeOfArg->getExprLoc())) {
// We only compute IDs for expressions if the warning is enabled, and
// cache the sizeof arg's ID.
if (SizeOfArgID == llvm::FoldingSetNodeID())
SizeOfArg->Profile(SizeOfArgID, Context, true);
llvm::FoldingSetNodeID DestID;
Dest->Profile(DestID, Context, true);
if (DestID == SizeOfArgID) {
// TODO: For strncpy() and friends, this could suggest sizeof(dst)
// over sizeof(src) as well.
unsigned ActionIdx = 0; // Default is to suggest dereferencing.
StringRef ReadableName = FnName->getName();
if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest))
if (UnaryOp->getOpcode() == UO_AddrOf)
ActionIdx = 1; // If its an address-of operator, just remove it.
if (!PointeeTy->isIncompleteType() &&
(Context.getTypeSize(PointeeTy) == Context.getCharWidth()))
ActionIdx = 2; // If the pointee's size is sizeof(char),
// suggest an explicit length.
// If the function is defined as a builtin macro, do not show macro
// expansion.
SourceLocation SL = SizeOfArg->getExprLoc();
SourceRange DSR = Dest->getSourceRange();
SourceRange SSR = SizeOfArg->getSourceRange();
SourceManager &SM = getSourceManager();
if (SM.isMacroArgExpansion(SL)) {
ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts);
SL = SM.getSpellingLoc(SL);
DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()),
SM.getSpellingLoc(DSR.getEnd()));
SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()),
SM.getSpellingLoc(SSR.getEnd()));
}
DiagRuntimeBehavior(SL, SizeOfArg,
PDiag(diag::warn_sizeof_pointer_expr_memaccess)
<< ReadableName
<< PointeeTy
<< DestTy
<< DSR
<< SSR);
DiagRuntimeBehavior(SL, SizeOfArg,
PDiag(diag::warn_sizeof_pointer_expr_memaccess_note)
<< ActionIdx
<< SSR);
break;
}
}
// Also check for cases where the sizeof argument is the exact same
// type as the memory argument, and where it points to a user-defined
// record type.
if (SizeOfArgTy != QualType()) {
if (PointeeTy->isRecordType() &&
Context.typesAreCompatible(SizeOfArgTy, DestTy)) {
DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest,
PDiag(diag::warn_sizeof_pointer_type_memaccess)
<< FnName << SizeOfArgTy << ArgIdx
<< PointeeTy << Dest->getSourceRange()
<< LenExpr->getSourceRange());
break;
}
}
// Always complain about dynamic classes.
bool IsContained;
if (const CXXRecordDecl *ContainedRD =
getContainedDynamicClass(PointeeTy, IsContained)) {
unsigned OperationType = 0;
// "overwritten" if we're warning about the destination for any call
// but memcmp; otherwise a verb appropriate to the call.
if (ArgIdx != 0 || BId == Builtin::BImemcmp) {
if (BId == Builtin::BImemcpy)
OperationType = 1;
else if(BId == Builtin::BImemmove)
OperationType = 2;
else if (BId == Builtin::BImemcmp)
OperationType = 3;
}
DiagRuntimeBehavior(
Dest->getExprLoc(), Dest,
PDiag(diag::warn_dyn_class_memaccess)
<< (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx)
<< FnName << IsContained << ContainedRD << OperationType
<< Call->getCallee()->getSourceRange());
} else if (PointeeTy.hasNonTrivialObjCLifetime() &&
BId != Builtin::BImemset)
DiagRuntimeBehavior(
Dest->getExprLoc(), Dest,
PDiag(diag::warn_arc_object_memaccess)
<< ArgIdx << FnName << PointeeTy
<< Call->getCallee()->getSourceRange());
else
continue;
DiagRuntimeBehavior(
Dest->getExprLoc(), Dest,
PDiag(diag::note_bad_memaccess_silence)
<< FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)"));
break;
}
}
}
// A little helper routine: ignore addition and subtraction of integer literals.
// This intentionally does not ignore all integer constant expressions because
// we don't want to remove sizeof().
static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) {
Ex = Ex->IgnoreParenCasts();
for (;;) {
const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex);
if (!BO || !BO->isAdditiveOp())
break;
const Expr *RHS = BO->getRHS()->IgnoreParenCasts();
const Expr *LHS = BO->getLHS()->IgnoreParenCasts();
if (isa<IntegerLiteral>(RHS))
Ex = LHS;
else if (isa<IntegerLiteral>(LHS))
Ex = RHS;
else
break;
}
return Ex;
}
static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty,
ASTContext &Context) {
// Only handle constant-sized or VLAs, but not flexible members.
if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) {
// Only issue the FIXIT for arrays of size > 1.
if (CAT->getSize().getSExtValue() <= 1)
return false;
} else if (!Ty->isVariableArrayType()) {
return false;
}
return true;
}
// Warn if the user has made the 'size' argument to strlcpy or strlcat
// be the size of the source, instead of the destination.
void Sema::CheckStrlcpycatArguments(const CallExpr *Call,
IdentifierInfo *FnName) {
// Don't crash if the user has the wrong number of arguments
if (Call->getNumArgs() != 3)
return;
const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context);
const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context);
const Expr *CompareWithSrc = nullptr;
if (CheckMemorySizeofForComparison(*this, SizeArg, FnName,
Call->getLocStart(), Call->getRParenLoc()))
return;
// Look for 'strlcpy(dst, x, sizeof(x))'
if (const Expr *Ex = getSizeOfExprArg(SizeArg))
CompareWithSrc = Ex;
else {
// Look for 'strlcpy(dst, x, strlen(x))'
if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) {
if (SizeCall->getBuiltinCallee() == Builtin::BIstrlen &&
SizeCall->getNumArgs() == 1)
CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context);
}
}
if (!CompareWithSrc)
return;
// Determine if the argument to sizeof/strlen is equal to the source
// argument. In principle there's all kinds of things you could do
// here, for instance creating an == expression and evaluating it with
// EvaluateAsBooleanCondition, but this uses a more direct technique:
const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg);
if (!SrcArgDRE)
return;
const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc);
if (!CompareWithSrcDRE ||
SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl())
return;
const Expr *OriginalSizeArg = Call->getArg(2);
Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size)
<< OriginalSizeArg->getSourceRange() << FnName;
// Output a FIXIT hint if the destination is an array (rather than a
// pointer to an array). This could be enhanced to handle some
// pointers if we know the actual size, like if DstArg is 'array+2'
// we could say 'sizeof(array)-2'.
const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts();
if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context))
return;
SmallString<128> sizeString;
llvm::raw_svector_ostream OS(sizeString);
OS << "sizeof(";
DstArg->printPretty(OS, nullptr, getPrintingPolicy());
OS << ")";
Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size)
<< FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(),
OS.str());
}
/// Check if two expressions refer to the same declaration.
static bool referToTheSameDecl(const Expr *E1, const Expr *E2) {
if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1))
if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2))
return D1->getDecl() == D2->getDecl();
return false;
}
static const Expr *getStrlenExprArg(const Expr *E) {
if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
const FunctionDecl *FD = CE->getDirectCallee();
if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen)
return nullptr;
return CE->getArg(0)->IgnoreParenCasts();
}
return nullptr;
}
// Warn on anti-patterns as the 'size' argument to strncat.
// The correct size argument should look like following:
// strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
void Sema::CheckStrncatArguments(const CallExpr *CE,
IdentifierInfo *FnName) {
// Don't crash if the user has the wrong number of arguments.
if (CE->getNumArgs() < 3)
return;
const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts();
const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts();
const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts();
if (CheckMemorySizeofForComparison(*this, LenArg, FnName, CE->getLocStart(),
CE->getRParenLoc()))
return;
// Identify common expressions, which are wrongly used as the size argument
// to strncat and may lead to buffer overflows.
unsigned PatternType = 0;
if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) {
// - sizeof(dst)
if (referToTheSameDecl(SizeOfArg, DstArg))
PatternType = 1;
// - sizeof(src)
else if (referToTheSameDecl(SizeOfArg, SrcArg))
PatternType = 2;
} else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) {
if (BE->getOpcode() == BO_Sub) {
const Expr *L = BE->getLHS()->IgnoreParenCasts();
const Expr *R = BE->getRHS()->IgnoreParenCasts();
// - sizeof(dst) - strlen(dst)
if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) &&
referToTheSameDecl(DstArg, getStrlenExprArg(R)))
PatternType = 1;
// - sizeof(src) - (anything)
else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L)))
PatternType = 2;
}
}
if (PatternType == 0)
return;
// Generate the diagnostic.
SourceLocation SL = LenArg->getLocStart();
SourceRange SR = LenArg->getSourceRange();
SourceManager &SM = getSourceManager();
// If the function is defined as a builtin macro, do not show macro expansion.
if (SM.isMacroArgExpansion(SL)) {
SL = SM.getSpellingLoc(SL);
SR = SourceRange(SM.getSpellingLoc(SR.getBegin()),
SM.getSpellingLoc(SR.getEnd()));
}
// Check if the destination is an array (rather than a pointer to an array).
QualType DstTy = DstArg->getType();
bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy,
Context);
if (!isKnownSizeArray) {
if (PatternType == 1)
Diag(SL, diag::warn_strncat_wrong_size) << SR;
else
Diag(SL, diag::warn_strncat_src_size) << SR;
return;
}
if (PatternType == 1)
Diag(SL, diag::warn_strncat_large_size) << SR;
else
Diag(SL, diag::warn_strncat_src_size) << SR;
SmallString<128> sizeString;
llvm::raw_svector_ostream OS(sizeString);
OS << "sizeof(";
DstArg->printPretty(OS, nullptr, getPrintingPolicy());
OS << ") - ";
OS << "strlen(";
DstArg->printPretty(OS, nullptr, getPrintingPolicy());
OS << ") - 1";
Diag(SL, diag::note_strncat_wrong_size)
<< FixItHint::CreateReplacement(SR, OS.str());
}
//===--- CHECK: Return Address of Stack Variable --------------------------===//
static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
Decl *ParentDecl);
static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars,
Decl *ParentDecl);
/// CheckReturnStackAddr - Check if a return statement returns the address
/// of a stack variable.
static void
CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType,
SourceLocation ReturnLoc) {
Expr *stackE = nullptr;
SmallVector<DeclRefExpr *, 8> refVars;
// Perform checking for returned stack addresses, local blocks,
// label addresses or references to temporaries.
if (lhsType->isPointerType() ||
(!S.getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) {
stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/nullptr);
} else if (lhsType->isReferenceType()) {
stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/nullptr);
}
if (!stackE)
return; // Nothing suspicious was found.
SourceLocation diagLoc;
SourceRange diagRange;
if (refVars.empty()) {
diagLoc = stackE->getLocStart();
diagRange = stackE->getSourceRange();
} else {
// We followed through a reference variable. 'stackE' contains the
// problematic expression but we will warn at the return statement pointing
// at the reference variable. We will later display the "trail" of
// reference variables using notes.
diagLoc = refVars[0]->getLocStart();
diagRange = refVars[0]->getSourceRange();
}
if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var.
S.Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref
: diag::warn_ret_stack_addr)
<< DR->getDecl()->getDeclName() << diagRange;
} else if (isa<BlockExpr>(stackE)) { // local block.
S.Diag(diagLoc, diag::err_ret_local_block) << diagRange;
} else if (isa<AddrLabelExpr>(stackE)) { // address of label.
S.Diag(diagLoc, diag::warn_ret_addr_label) << diagRange;
} else { // local temporary.
S.Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref
: diag::warn_ret_local_temp_addr)
<< diagRange;
}
// Display the "trail" of reference variables that we followed until we
// found the problematic expression using notes.
for (unsigned i = 0, e = refVars.size(); i != e; ++i) {
VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl());
// If this var binds to another reference var, show the range of the next
// var, otherwise the var binds to the problematic expression, in which case
// show the range of the expression.
SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange()
: stackE->getSourceRange();
S.Diag(VD->getLocation(), diag::note_ref_var_local_bind)
<< VD->getDeclName() << range;
}
}
/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that
/// check if the expression in a return statement evaluates to an address
/// to a location on the stack, a local block, an address of a label, or a
/// reference to local temporary. The recursion is used to traverse the
/// AST of the return expression, with recursion backtracking when we
/// encounter a subexpression that (1) clearly does not lead to one of the
/// above problematic expressions (2) is something we cannot determine leads to
/// a problematic expression based on such local checking.
///
/// Both EvalAddr and EvalVal follow through reference variables to evaluate
/// the expression that they point to. Such variables are added to the
/// 'refVars' vector so that we know what the reference variable "trail" was.
///
/// EvalAddr processes expressions that are pointers that are used as
/// references (and not L-values). EvalVal handles all other values.
/// At the base case of the recursion is a check for the above problematic
/// expressions.
///
/// This implementation handles:
///
/// * pointer-to-pointer casts
/// * implicit conversions from array references to pointers
/// * taking the address of fields
/// * arbitrary interplay between "&" and "*" operators
/// * pointer arithmetic from an address of a stack variable
/// * taking the address of an array element where the array is on the stack
static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
Decl *ParentDecl) {
if (E->isTypeDependent())
return nullptr;
// We should only be called for evaluating pointer expressions.
assert((E->getType()->isAnyPointerType() ||
E->getType()->isBlockPointerType() ||
E->getType()->isObjCQualifiedIdType()) &&
"EvalAddr only works on pointers");
E = E->IgnoreParens();
// Our "symbolic interpreter" is just a dispatch off the currently
// viewed AST node. We then recursively traverse the AST by calling
// EvalAddr and EvalVal appropriately.
switch (E->getStmtClass()) {
case Stmt::DeclRefExprClass: {
DeclRefExpr *DR = cast<DeclRefExpr>(E);
// If we leave the immediate function, the lifetime isn't about to end.
if (DR->refersToEnclosingLocal())
return nullptr;
if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
// If this is a reference variable, follow through to the expression that
// it points to.
if (V->hasLocalStorage() &&
V->getType()->isReferenceType() && V->hasInit()) {
// Add the reference variable to the "trail".
refVars.push_back(DR);
return EvalAddr(V->getInit(), refVars, ParentDecl);
}
return nullptr;
}
case Stmt::UnaryOperatorClass: {
// The only unary operator that make sense to handle here
// is AddrOf. All others don't make sense as pointers.
UnaryOperator *U = cast<UnaryOperator>(E);
if (U->getOpcode() == UO_AddrOf)
return EvalVal(U->getSubExpr(), refVars, ParentDecl);
else
return nullptr;
}
case Stmt::BinaryOperatorClass: {
// Handle pointer arithmetic. All other binary operators are not valid
// in this context.
BinaryOperator *B = cast<BinaryOperator>(E);
BinaryOperatorKind op = B->getOpcode();
if (op != BO_Add && op != BO_Sub)
return nullptr;
Expr *Base = B->getLHS();
// Determine which argument is the real pointer base. It could be
// the RHS argument instead of the LHS.
if (!Base->getType()->isPointerType()) Base = B->getRHS();
assert (Base->getType()->isPointerType());
return EvalAddr(Base, refVars, ParentDecl);
}
// For conditional operators we need to see if either the LHS or RHS are
// valid DeclRefExpr*s. If one of them is valid, we return it.
case Stmt::ConditionalOperatorClass: {
ConditionalOperator *C = cast<ConditionalOperator>(E);
// Handle the GNU extension for missing LHS.
// FIXME: That isn't a ConditionalOperator, so doesn't get here.
if (Expr *LHSExpr = C->getLHS()) {
// In C++, we can have a throw-expression, which has 'void' type.
if (!LHSExpr->getType()->isVoidType())
if (Expr *LHS = EvalAddr(LHSExpr, refVars, ParentDecl))
return LHS;
}
// In C++, we can have a throw-expression, which has 'void' type.
if (C->getRHS()->getType()->isVoidType())
return nullptr;
return EvalAddr(C->getRHS(), refVars, ParentDecl);
}
case Stmt::BlockExprClass:
if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures())
return E; // local block.
return nullptr;
case Stmt::AddrLabelExprClass:
return E; // address of label.
case Stmt::ExprWithCleanupsClass:
return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,
ParentDecl);
// For casts, we need to handle conversions from arrays to
// pointer values, and pointer-to-pointer conversions.
case Stmt::ImplicitCastExprClass:
case Stmt::CStyleCastExprClass:
case Stmt::CXXFunctionalCastExprClass:
case Stmt::ObjCBridgedCastExprClass:
case Stmt::CXXStaticCastExprClass:
case Stmt::CXXDynamicCastExprClass:
case Stmt::CXXConstCastExprClass:
case Stmt::CXXReinterpretCastExprClass: {
Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
switch (cast<CastExpr>(E)->getCastKind()) {
case CK_LValueToRValue:
case CK_NoOp:
case CK_BaseToDerived:
case CK_DerivedToBase:
case CK_UncheckedDerivedToBase:
case CK_Dynamic:
case CK_CPointerToObjCPointerCast:
case CK_BlockPointerToObjCPointerCast:
case CK_AnyPointerToBlockPointerCast:
return EvalAddr(SubExpr, refVars, ParentDecl);
case CK_ArrayToPointerDecay:
return EvalVal(SubExpr, refVars, ParentDecl);
case CK_BitCast:
if (SubExpr->getType()->isAnyPointerType() ||
SubExpr->getType()->isBlockPointerType() ||
SubExpr->getType()->isObjCQualifiedIdType())
return EvalAddr(SubExpr, refVars, ParentDecl);
else
return nullptr;
default:
return nullptr;
}
}
case Stmt::MaterializeTemporaryExprClass:
if (Expr *Result = EvalAddr(
cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
refVars, ParentDecl))
return Result;
return E;
// Everything else: we simply don't reason about them.
default:
return nullptr;
}
}
/// EvalVal - This function is complements EvalAddr in the mutual recursion.
/// See the comments for EvalAddr for more details.
static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
Decl *ParentDecl) {
do {
// We should only be called for evaluating non-pointer expressions, or
// expressions with a pointer type that are not used as references but instead
// are l-values (e.g., DeclRefExpr with a pointer type).
// Our "symbolic interpreter" is just a dispatch off the currently
// viewed AST node. We then recursively traverse the AST by calling
// EvalAddr and EvalVal appropriately.
E = E->IgnoreParens();
switch (E->getStmtClass()) {
case Stmt::ImplicitCastExprClass: {
ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E);
if (IE->getValueKind() == VK_LValue) {
E = IE->getSubExpr();
continue;
}
return nullptr;
}
case Stmt::ExprWithCleanupsClass:
return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl);
case Stmt::DeclRefExprClass: {
// When we hit a DeclRefExpr we are looking at code that refers to a
// variable's name. If it's not a reference variable we check if it has
// local storage within the function, and if so, return the expression.
DeclRefExpr *DR = cast<DeclRefExpr>(E);
// If we leave the immediate function, the lifetime isn't about to end.
if (DR->refersToEnclosingLocal())
return nullptr;
if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) {
// Check if it refers to itself, e.g. "int& i = i;".
if (V == ParentDecl)
return DR;
if (V->hasLocalStorage()) {
if (!V->getType()->isReferenceType())
return DR;
// Reference variable, follow through to the expression that
// it points to.
if (V->hasInit()) {
// Add the reference variable to the "trail".
refVars.push_back(DR);
return EvalVal(V->getInit(), refVars, V);
}
}
}
return nullptr;
}
case Stmt::UnaryOperatorClass: {
// The only unary operator that make sense to handle here
// is Deref. All others don't resolve to a "name." This includes
// handling all sorts of rvalues passed to a unary operator.
UnaryOperator *U = cast<UnaryOperator>(E);
if (U->getOpcode() == UO_Deref)
return EvalAddr(U->getSubExpr(), refVars, ParentDecl);
return nullptr;
}
case Stmt::ArraySubscriptExprClass: {
// Array subscripts are potential references to data on the stack. We
// retrieve the DeclRefExpr* for the array variable if it indeed
// has local storage.
return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl);
}
case Stmt::ConditionalOperatorClass: {
// For conditional operators we need to see if either the LHS or RHS are
// non-NULL Expr's. If one is non-NULL, we return it.
ConditionalOperator *C = cast<ConditionalOperator>(E);
// Handle the GNU extension for missing LHS.
if (Expr *LHSExpr = C->getLHS()) {
// In C++, we can have a throw-expression, which has 'void' type.
if (!LHSExpr->getType()->isVoidType())
if (Expr *LHS = EvalVal(LHSExpr, refVars, ParentDecl))
return LHS;
}
// In C++, we can have a throw-expression, which has 'void' type.
if (C->getRHS()->getType()->isVoidType())
return nullptr;
return EvalVal(C->getRHS(), refVars, ParentDecl);
}
// Accesses to members are potential references to data on the stack.
case Stmt::MemberExprClass: {
MemberExpr *M = cast<MemberExpr>(E);
// Check for indirect access. We only want direct field accesses.
if (M->isArrow())
return nullptr;
// Check whether the member type is itself a reference, in which case
// we're not going to refer to the member, but to what the member refers to.
if (M->getMemberDecl()->getType()->isReferenceType())
return nullptr;
return EvalVal(M->getBase(), refVars, ParentDecl);
}
case Stmt::MaterializeTemporaryExprClass:
if (Expr *Result = EvalVal(
cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
refVars, ParentDecl))
return Result;
return E;
default:
// Check that we don't return or take the address of a reference to a
// temporary. This is only useful in C++.
if (!E->isTypeDependent() && E->isRValue())
return E;
// Everything else: we simply don't reason about them.
return nullptr;
}
} while (true);
}
void
Sema::CheckReturnValExpr(Expr *RetValExp, QualType lhsType,
SourceLocation ReturnLoc,
bool isObjCMethod,
const AttrVec *Attrs,
const FunctionDecl *FD) {
CheckReturnStackAddr(*this, RetValExp, lhsType, ReturnLoc);
// Check if the return value is null but should not be.
if (Attrs && hasSpecificAttr<ReturnsNonNullAttr>(*Attrs) &&
CheckNonNullExpr(*this, RetValExp))
Diag(ReturnLoc, diag::warn_null_ret)
<< (isObjCMethod ? 1 : 0) << RetValExp->getSourceRange();
// C++11 [basic.stc.dynamic.allocation]p4:
// If an allocation function declared with a non-throwing
// exception-specification fails to allocate storage, it shall return
// a null pointer. Any other allocation function that fails to allocate
// storage shall indicate failure only by throwing an exception [...]
if (FD) {
OverloadedOperatorKind Op = FD->getOverloadedOperator();
if (Op == OO_New || Op == OO_Array_New) {
const FunctionProtoType *Proto
= FD->getType()->castAs<FunctionProtoType>();
if (!Proto->isNothrow(Context, /*ResultIfDependent*/true) &&
CheckNonNullExpr(*this, RetValExp))
Diag(ReturnLoc, diag::warn_operator_new_returns_null)
<< FD << getLangOpts().CPlusPlus11;
}
}
}
//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===//
/// Check for comparisons of floating point operands using != and ==.
/// Issue a warning if these are no self-comparisons, as they are not likely
/// to do what the programmer intended.
void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) {
Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts();
Expr* RightExprSansParen = RHS->IgnoreParenImpCasts();
// Special case: check for x == x (which is OK).
// Do not emit warnings for such cases.
if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen))
if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen))
if (DRL->getDecl() == DRR->getDecl())
return;
// Special case: check for comparisons against literals that can be exactly
// represented by APFloat. In such cases, do not emit a warning. This
// is a heuristic: often comparison against such literals are used to
// detect if a value in a variable has not changed. This clearly can
// lead to false negatives.
if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) {
if (FLL->isExact())
return;
} else
if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen))
if (FLR->isExact())
return;
// Check for comparisons with builtin types.
if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen))
if (CL->getBuiltinCallee())
return;
if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen))
if (CR->getBuiltinCallee())
return;
// Emit the diagnostic.
Diag(Loc, diag::warn_floatingpoint_eq)
<< LHS->getSourceRange() << RHS->getSourceRange();
}
//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===//
//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===//
namespace {
/// Structure recording the 'active' range of an integer-valued
/// expression.
struct IntRange {
/// The number of bits active in the int.
unsigned Width;
/// True if the int is known not to have negative values.
bool NonNegative;
IntRange(unsigned Width, bool NonNegative)
: Width(Width), NonNegative(NonNegative)
{}
/// Returns the range of the bool type.
static IntRange forBoolType() {
return IntRange(1, true);
}
/// Returns the range of an opaque value of the given integral type.
static IntRange forValueOfType(ASTContext &C, QualType T) {
return forValueOfCanonicalType(C,
T->getCanonicalTypeInternal().getTypePtr());
}
/// Returns the range of an opaque value of a canonical integral type.
static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) {
assert(T->isCanonicalUnqualified());
if (const VectorType *VT = dyn_cast<VectorType>(T))
T = VT->getElementType().getTypePtr();
if (const ComplexType *CT = dyn_cast<ComplexType>(T))
T = CT->getElementType().getTypePtr();
// For enum types, use the known bit width of the enumerators.
if (const EnumType *ET = dyn_cast<EnumType>(T)) {
EnumDecl *Enum = ET->getDecl();
if (!Enum->isCompleteDefinition())
return IntRange(C.getIntWidth(QualType(T, 0)), false);
unsigned NumPositive = Enum->getNumPositiveBits();
unsigned NumNegative = Enum->getNumNegativeBits();
if (NumNegative == 0)
return IntRange(NumPositive, true/*NonNegative*/);
else
return IntRange(std::max(NumPositive + 1, NumNegative),
false/*NonNegative*/);
}
const BuiltinType *BT = cast<BuiltinType>(T);
assert(BT->isInteger());
return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
}
/// Returns the "target" range of a canonical integral type, i.e.
/// the range of values expressible in the type.
///
/// This matches forValueOfCanonicalType except that enums have the
/// full range of their type, not the range of their enumerators.
static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) {
assert(T->isCanonicalUnqualified());
if (const VectorType *VT = dyn_cast<VectorType>(T))
T = VT->getElementType().getTypePtr();
if (const ComplexType *CT = dyn_cast<ComplexType>(T))
T = CT->getElementType().getTypePtr();
if (const EnumType *ET = dyn_cast<EnumType>(T))
T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr();
const BuiltinType *BT = cast<BuiltinType>(T);
assert(BT->isInteger());
return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
}
/// Returns the supremum of two ranges: i.e. their conservative merge.
static IntRange join(IntRange L, IntRange R) {
return IntRange(std::max(L.Width, R.Width),
L.NonNegative && R.NonNegative);
}
/// Returns the infinum of two ranges: i.e. their aggressive merge.
static IntRange meet(IntRange L, IntRange R) {
return IntRange(std::min(L.Width, R.Width),
L.NonNegative || R.NonNegative);
}
};
static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value,
unsigned MaxWidth) {
if (value.isSigned() && value.isNegative())
return IntRange(value.getMinSignedBits(), false);
if (value.getBitWidth() > MaxWidth)
value = value.trunc(MaxWidth);
// isNonNegative() just checks the sign bit without considering
// signedness.
return IntRange(value.getActiveBits(), true);
}
static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty,
unsigned MaxWidth) {
if (result.isInt())
return GetValueRange(C, result.getInt(), MaxWidth);
if (result.isVector()) {
IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth);
for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) {
IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth);
R = IntRange::join(R, El);
}
return R;
}
if (result.isComplexInt()) {
IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth);
IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth);
return IntRange::join(R, I);
}
// This can happen with lossless casts to intptr_t of "based" lvalues.
// Assume it might use arbitrary bits.
// FIXME: The only reason we need to pass the type in here is to get
// the sign right on this one case. It would be nice if APValue
// preserved this.
assert(result.isLValue() || result.isAddrLabelDiff());
return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType());
}
static QualType GetExprType(Expr *E) {
QualType Ty = E->getType();
if (const AtomicType *AtomicRHS = Ty->getAs<AtomicType>())
Ty = AtomicRHS->getValueType();
return Ty;
}
/// Pseudo-evaluate the given integer expression, estimating the
/// range of values it might take.
///
/// \param MaxWidth - the width to which the value will be truncated
static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
E = E->IgnoreParens();
// Try a full evaluation first.
Expr::EvalResult result;
if (E->EvaluateAsRValue(result, C))
return GetValueRange(C, result.Val, GetExprType(E), MaxWidth);
// I think we only want to look through implicit casts here; if the
// user has an explicit widening cast, we should treat the value as
// being of the new, wider type.
if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue)
return GetExprRange(C, CE->getSubExpr(), MaxWidth);
IntRange OutputTypeRange = IntRange::forValueOfType(C, GetExprType(CE));
bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast);
// Assume that non-integer casts can span the full range of the type.
if (!isIntegerCast)
return OutputTypeRange;
IntRange SubRange
= GetExprRange(C, CE->getSubExpr(),
std::min(MaxWidth, OutputTypeRange.Width));
// Bail out if the subexpr's range is as wide as the cast type.
if (SubRange.Width >= OutputTypeRange.Width)
return OutputTypeRange;
// Otherwise, we take the smaller width, and we're non-negative if
// either the output type or the subexpr is.
return IntRange(SubRange.Width,
SubRange.NonNegative || OutputTypeRange.NonNegative);
}
if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
// If we can fold the condition, just take that operand.
bool CondResult;
if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C))
return GetExprRange(C, CondResult ? CO->getTrueExpr()
: CO->getFalseExpr(),
MaxWidth);
// Otherwise, conservatively merge.
IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth);
IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth);
return IntRange::join(L, R);
}
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
switch (BO->getOpcode()) {
// Boolean-valued operations are single-bit and positive.
case BO_LAnd:
case BO_LOr:
case BO_LT:
case BO_GT:
case BO_LE:
case BO_GE:
case BO_EQ:
case BO_NE:
return IntRange::forBoolType();
// The type of the assignments is the type of the LHS, so the RHS
// is not necessarily the same type.
case BO_MulAssign:
case BO_DivAssign:
case BO_RemAssign:
case BO_AddAssign:
case BO_SubAssign:
case BO_XorAssign:
case BO_OrAssign:
// TODO: bitfields?
return IntRange::forValueOfType(C, GetExprType(E));
// Simple assignments just pass through the RHS, which will have
// been coerced to the LHS type.
case BO_Assign:
// TODO: bitfields?
return GetExprRange(C, BO->getRHS(), MaxWidth);
// Operations with opaque sources are black-listed.
case BO_PtrMemD:
case BO_PtrMemI:
return IntRange::forValueOfType(C, GetExprType(E));
// Bitwise-and uses the *infinum* of the two source ranges.
case BO_And:
case BO_AndAssign:
return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth),
GetExprRange(C, BO->getRHS(), MaxWidth));
// Left shift gets black-listed based on a judgement call.
case BO_Shl:
// ...except that we want to treat '1 << (blah)' as logically
// positive. It's an important idiom.
if (IntegerLiteral *I
= dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) {
if (I->getValue() == 1) {
IntRange R = IntRange::forValueOfType(C, GetExprType(E));
return IntRange(R.Width, /*NonNegative*/ true);
}
}
// fallthrough
case BO_ShlAssign:
return IntRange::forValueOfType(C, GetExprType(E));
// Right shift by a constant can narrow its left argument.
case BO_Shr:
case BO_ShrAssign: {
IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
// If the shift amount is a positive constant, drop the width by
// that much.
llvm::APSInt shift;
if (BO->getRHS()->isIntegerConstantExpr(shift, C) &&
shift.isNonNegative()) {
unsigned zext = shift.getZExtValue();
if (zext >= L.Width)
L.Width = (L.NonNegative ? 0 : 1);
else
L.Width -= zext;
}
return L;
}
// Comma acts as its right operand.
case BO_Comma:
return GetExprRange(C, BO->getRHS(), MaxWidth);
// Black-list pointer subtractions.
case BO_Sub:
if (BO->getLHS()->getType()->isPointerType())
return IntRange::forValueOfType(C, GetExprType(E));
break;
// The width of a division result is mostly determined by the size
// of the LHS.
case BO_Div: {
// Don't 'pre-truncate' the operands.
unsigned opWidth = C.getIntWidth(GetExprType(E));
IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
// If the divisor is constant, use that.
llvm::APSInt divisor;
if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) {
unsigned log2 = divisor.logBase2(); // floor(log_2(divisor))
if (log2 >= L.Width)
L.Width = (L.NonNegative ? 0 : 1);
else
L.Width = std::min(L.Width - log2, MaxWidth);
return L;
}
// Otherwise, just use the LHS's width.
IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
return IntRange(L.Width, L.NonNegative && R.NonNegative);
}
// The result of a remainder can't be larger than the result of
// either side.
case BO_Rem: {
// Don't 'pre-truncate' the operands.
unsigned opWidth = C.getIntWidth(GetExprType(E));
IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
IntRange meet = IntRange::meet(L, R);
meet.Width = std::min(meet.Width, MaxWidth);
return meet;
}
// The default behavior is okay for these.
case BO_Mul:
case BO_Add:
case BO_Xor:
case BO_Or:
break;
}
// The default case is to treat the operation as if it were closed
// on the narrowest type that encompasses both operands.
IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth);
return IntRange::join(L, R);
}
if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
switch (UO->getOpcode()) {
// Boolean-valued operations are white-listed.
case UO_LNot:
return IntRange::forBoolType();
// Operations with opaque sources are black-listed.
case UO_Deref:
case UO_AddrOf: // should be impossible
return IntRange::forValueOfType(C, GetExprType(E));
default:
return GetExprRange(C, UO->getSubExpr(), MaxWidth);
}
}
if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E))
return GetExprRange(C, OVE->getSourceExpr(), MaxWidth);
if (FieldDecl *BitField = E->getSourceBitField())
return IntRange(BitField->getBitWidthValue(C),
BitField->getType()->isUnsignedIntegerOrEnumerationType());
return IntRange::forValueOfType(C, GetExprType(E));
}
static IntRange GetExprRange(ASTContext &C, Expr *E) {
return GetExprRange(C, E, C.getIntWidth(GetExprType(E)));
}
/// Checks whether the given value, which currently has the given
/// source semantics, has the same value when coerced through the
/// target semantics.
static bool IsSameFloatAfterCast(const llvm::APFloat &value,
const llvm::fltSemantics &Src,
const llvm::fltSemantics &Tgt) {
llvm::APFloat truncated = value;
bool ignored;
truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored);
truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored);
return truncated.bitwiseIsEqual(value);
}
/// Checks whether the given value, which currently has the given
/// source semantics, has the same value when coerced through the
/// target semantics.
///
/// The value might be a vector of floats (or a complex number).
static bool IsSameFloatAfterCast(const APValue &value,
const llvm::fltSemantics &Src,
const llvm::fltSemantics &Tgt) {
if (value.isFloat())
return IsSameFloatAfterCast(value.getFloat(), Src, Tgt);
if (value.isVector()) {
for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i)
if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt))
return false;
return true;
}
assert(value.isComplexFloat());
return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) &&
IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
}
static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC);
static bool IsZero(Sema &S, Expr *E) {
// Suppress cases where we are comparing against an enum constant.
if (const DeclRefExpr *DR =
dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
if (isa<EnumConstantDecl>(DR->getDecl()))
return false;
// Suppress cases where the '0' value is expanded from a macro.
if (E->getLocStart().isMacroID())
return false;
llvm::APSInt Value;
return E->isIntegerConstantExpr(Value, S.Context) && Value == 0;
}
static bool HasEnumType(Expr *E) {
// Strip off implicit integral promotions.
while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
if (ICE->getCastKind() != CK_IntegralCast &&
ICE->getCastKind() != CK_NoOp)
break;
E = ICE->getSubExpr();
}
return E->getType()->isEnumeralType();
}
static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
// Disable warning in template instantiations.
if (!S.ActiveTemplateInstantiations.empty())
return;
BinaryOperatorKind op = E->getOpcode();
if (E->isValueDependent())
return;
if (op == BO_LT && IsZero(S, E->getRHS())) {
S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
<< "< 0" << "false" << HasEnumType(E->getLHS())
<< E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
} else if (op == BO_GE && IsZero(S, E->getRHS())) {
S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
<< ">= 0" << "true" << HasEnumType(E->getLHS())
<< E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
} else if (op == BO_GT && IsZero(S, E->getLHS())) {
S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
<< "0 >" << "false" << HasEnumType(E->getRHS())
<< E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
} else if (op == BO_LE && IsZero(S, E->getLHS())) {
S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
<< "0 <=" << "true" << HasEnumType(E->getRHS())
<< E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
}
}
static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E,
Expr *Constant, Expr *Other,
llvm::APSInt Value,
bool RhsConstant) {
// Disable warning in template instantiations.
if (!S.ActiveTemplateInstantiations.empty())
return;
// TODO: Investigate using GetExprRange() to get tighter bounds
// on the bit ranges.
QualType OtherT = Other->getType();
IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT);
unsigned OtherWidth = OtherRange.Width;
bool OtherIsBooleanType = Other->isKnownToHaveBooleanValue();
// 0 values are handled later by CheckTrivialUnsignedComparison().
if ((Value == 0) && (!OtherIsBooleanType))
return;
BinaryOperatorKind op = E->getOpcode();
bool IsTrue = true;
// Used for diagnostic printout.
enum {
LiteralConstant = 0,
CXXBoolLiteralTrue,
CXXBoolLiteralFalse
} LiteralOrBoolConstant = LiteralConstant;
if (!OtherIsBooleanType) {
QualType ConstantT = Constant->getType();
QualType CommonT = E->getLHS()->getType();
if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT))
return;
assert((OtherT->isIntegerType() && ConstantT->isIntegerType()) &&
"comparison with non-integer type");
bool ConstantSigned = ConstantT->isSignedIntegerType();
bool CommonSigned = CommonT->isSignedIntegerType();
bool EqualityOnly = false;
if (CommonSigned) {
// The common type is signed, therefore no signed to unsigned conversion.
if (!OtherRange.NonNegative) {
// Check that the constant is representable in type OtherT.
if (ConstantSigned) {
if (OtherWidth >= Value.getMinSignedBits())
return;
} else { // !ConstantSigned
if (OtherWidth >= Value.getActiveBits() + 1)
return;
}
} else { // !OtherSigned
// Check that the constant is representable in type OtherT.
// Negative values are out of range.
if (ConstantSigned) {
if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits())
return;
} else { // !ConstantSigned
if (OtherWidth >= Value.getActiveBits())
return;
}
}
} else { // !CommonSigned
if (OtherRange.NonNegative) {
if (OtherWidth >= Value.getActiveBits())
return;
} else { // OtherSigned
assert(!ConstantSigned &&
"Two signed types converted to unsigned types.");
// Check to see if the constant is representable in OtherT.
if (OtherWidth > Value.getActiveBits())
return;
// Check to see if the constant is equivalent to a negative value
// cast to CommonT.
if (S.Context.getIntWidth(ConstantT) ==
S.Context.getIntWidth(CommonT) &&
Value.isNegative() && Value.getMinSignedBits() <= OtherWidth)
return;
// The constant value rests between values that OtherT can represent
// after conversion. Relational comparison still works, but equality
// comparisons will be tautological.
EqualityOnly = true;
}
}
bool PositiveConstant = !ConstantSigned || Value.isNonNegative();
if (op == BO_EQ || op == BO_NE) {
IsTrue = op == BO_NE;
} else if (EqualityOnly) {
return;
} else if (RhsConstant) {
if (op == BO_GT || op == BO_GE)
IsTrue = !PositiveConstant;
else // op == BO_LT || op == BO_LE
IsTrue = PositiveConstant;
} else {
if (op == BO_LT || op == BO_LE)
IsTrue = !PositiveConstant;
else // op == BO_GT || op == BO_GE
IsTrue = PositiveConstant;
}
} else {
// Other isKnownToHaveBooleanValue
enum CompareBoolWithConstantResult { AFals, ATrue, Unkwn };
enum ConstantValue { LT_Zero, Zero, One, GT_One, SizeOfConstVal };
enum ConstantSide { Lhs, Rhs, SizeOfConstSides };
static const struct LinkedConditions {
CompareBoolWithConstantResult BO_LT_OP[SizeOfConstSides][SizeOfConstVal];
CompareBoolWithConstantResult BO_GT_OP[SizeOfConstSides][SizeOfConstVal];
CompareBoolWithConstantResult BO_LE_OP[SizeOfConstSides][SizeOfConstVal];
CompareBoolWithConstantResult BO_GE_OP[SizeOfConstSides][SizeOfConstVal];
CompareBoolWithConstantResult BO_EQ_OP[SizeOfConstSides][SizeOfConstVal];
CompareBoolWithConstantResult BO_NE_OP[SizeOfConstSides][SizeOfConstVal];
} TruthTable = {
// Constant on LHS. | Constant on RHS. |
// LT_Zero| Zero | One |GT_One| LT_Zero| Zero | One |GT_One|
{ { ATrue, Unkwn, AFals, AFals }, { AFals, AFals, Unkwn, ATrue } },
{ { AFals, AFals, Unkwn, ATrue }, { ATrue, Unkwn, AFals, AFals } },
{ { ATrue, ATrue, Unkwn, AFals }, { AFals, Unkwn, ATrue, ATrue } },
{ { AFals, Unkwn, ATrue, ATrue }, { ATrue, ATrue, Unkwn, AFals } },
{ { AFals, Unkwn, Unkwn, AFals }, { AFals, Unkwn, Unkwn, AFals } },
{ { ATrue, Unkwn, Unkwn, ATrue }, { ATrue, Unkwn, Unkwn, ATrue } }
};
bool ConstantIsBoolLiteral = isa<CXXBoolLiteralExpr>(Constant);
enum ConstantValue ConstVal = Zero;
if (Value.isUnsigned() || Value.isNonNegative()) {
if (Value == 0) {
LiteralOrBoolConstant =
ConstantIsBoolLiteral ? CXXBoolLiteralFalse : LiteralConstant;
ConstVal = Zero;
} else if (Value == 1) {
LiteralOrBoolConstant =
ConstantIsBoolLiteral ? CXXBoolLiteralTrue : LiteralConstant;
ConstVal = One;
} else {
LiteralOrBoolConstant = LiteralConstant;
ConstVal = GT_One;
}
} else {
ConstVal = LT_Zero;
}
CompareBoolWithConstantResult CmpRes;
switch (op) {
case BO_LT:
CmpRes = TruthTable.BO_LT_OP[RhsConstant][ConstVal];
break;
case BO_GT:
CmpRes = TruthTable.BO_GT_OP[RhsConstant][ConstVal];
break;
case BO_LE:
CmpRes = TruthTable.BO_LE_OP[RhsConstant][ConstVal];
break;
case BO_GE:
CmpRes = TruthTable.BO_GE_OP[RhsConstant][ConstVal];
break;
case BO_EQ:
CmpRes = TruthTable.BO_EQ_OP[RhsConstant][ConstVal];
break;
case BO_NE:
CmpRes = TruthTable.BO_NE_OP[RhsConstant][ConstVal];
break;
default:
CmpRes = Unkwn;
break;
}
if (CmpRes == AFals) {
IsTrue = false;
} else if (CmpRes == ATrue) {
IsTrue = true;
} else {
return;
}
}
// If this is a comparison to an enum constant, include that
// constant in the diagnostic.
const EnumConstantDecl *ED = nullptr;
if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Constant))
ED = dyn_cast<EnumConstantDecl>(DR->getDecl());
SmallString<64> PrettySourceValue;
llvm::raw_svector_ostream OS(PrettySourceValue);
if (ED)
OS << '\'' << *ED << "' (" << Value << ")";
else
OS << Value;
S.DiagRuntimeBehavior(
E->getOperatorLoc(), E,
S.PDiag(diag::warn_out_of_range_compare)
<< OS.str() << LiteralOrBoolConstant
<< OtherT << (OtherIsBooleanType && !OtherT->isBooleanType()) << IsTrue
<< E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange());
}
/// Analyze the operands of the given comparison. Implements the
/// fallback case from AnalyzeComparison.
static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) {
AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
}
/// \brief Implements -Wsign-compare.
///
/// \param E the binary operator to check for warnings
static void AnalyzeComparison(Sema &S, BinaryOperator *E) {
// The type the comparison is being performed in.
QualType T = E->getLHS()->getType();
assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())
&& "comparison with mismatched types");
if (E->isValueDependent())
return AnalyzeImpConvsInComparison(S, E);
Expr *LHS = E->getLHS()->IgnoreParenImpCasts();
Expr *RHS = E->getRHS()->IgnoreParenImpCasts();
bool IsComparisonConstant = false;
// Check whether an integer constant comparison results in a value
// of 'true' or 'false'.
if (T->isIntegralType(S.Context)) {
llvm::APSInt RHSValue;
bool IsRHSIntegralLiteral =
RHS->isIntegerConstantExpr(RHSValue, S.Context);
llvm::APSInt LHSValue;
bool IsLHSIntegralLiteral =
LHS->isIntegerConstantExpr(LHSValue, S.Context);
if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral)
DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true);
else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral)
DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false);
else
IsComparisonConstant =
(IsRHSIntegralLiteral && IsLHSIntegralLiteral);
} else if (!T->hasUnsignedIntegerRepresentation())
IsComparisonConstant = E->isIntegerConstantExpr(S.Context);
// We don't do anything special if this isn't an unsigned integral
// comparison: we're only interested in integral comparisons, and
// signed comparisons only happen in cases we don't care to warn about.
//
// We also don't care about value-dependent expressions or expressions
// whose result is a constant.
if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant)
return AnalyzeImpConvsInComparison(S, E);
// Check to see if one of the (unmodified) operands is of different
// signedness.
Expr *signedOperand, *unsignedOperand;
if (LHS->getType()->hasSignedIntegerRepresentation()) {
assert(!RHS->getType()->hasSignedIntegerRepresentation() &&
"unsigned comparison between two signed integer expressions?");
signedOperand = LHS;
unsignedOperand = RHS;
} else if (RHS->getType()->hasSignedIntegerRepresentation()) {
signedOperand = RHS;
unsignedOperand = LHS;
} else {
CheckTrivialUnsignedComparison(S, E);
return AnalyzeImpConvsInComparison(S, E);
}
// Otherwise, calculate the effective range of the signed operand.
IntRange signedRange = GetExprRange(S.Context, signedOperand);
// Go ahead and analyze implicit conversions in the operands. Note
// that we skip the implicit conversions on both sides.
AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc());
AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc());
// If the signed range is non-negative, -Wsign-compare won't fire,
// but we should still check for comparisons which are always true
// or false.
if (signedRange.NonNegative)
return CheckTrivialUnsignedComparison(S, E);
// For (in)equality comparisons, if the unsigned operand is a
// constant which cannot collide with a overflowed signed operand,
// then reinterpreting the signed operand as unsigned will not
// change the result of the comparison.
if (E->isEqualityOp()) {
unsigned comparisonWidth = S.Context.getIntWidth(T);
IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand);
// We should never be unable to prove that the unsigned operand is
// non-negative.
assert(unsignedRange.NonNegative && "unsigned range includes negative?");
if (unsignedRange.Width < comparisonWidth)
return;
}
S.DiagRuntimeBehavior(E->getOperatorLoc(), E,
S.PDiag(diag::warn_mixed_sign_comparison)
<< LHS->getType() << RHS->getType()
<< LHS->getSourceRange() << RHS->getSourceRange());
}
/// Analyzes an attempt to assign the given value to a bitfield.
///
/// Returns true if there was something fishy about the attempt.
static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init,
SourceLocation InitLoc) {
assert(Bitfield->isBitField());
if (Bitfield->isInvalidDecl())
return false;
// White-list bool bitfields.
if (Bitfield->getType()->isBooleanType())
return false;
// Ignore value- or type-dependent expressions.
if (Bitfield->getBitWidth()->isValueDependent() ||
Bitfield->getBitWidth()->isTypeDependent() ||
Init->isValueDependent() ||
Init->isTypeDependent())
return false;
Expr *OriginalInit = Init->IgnoreParenImpCasts();
llvm::APSInt Value;
if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects))
return false;
unsigned OriginalWidth = Value.getBitWidth();
unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context);
if (OriginalWidth <= FieldWidth)
return false;
// Compute the value which the bitfield will contain.
llvm::APSInt TruncatedValue = Value.trunc(FieldWidth);
TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType());
// Check whether the stored value is equal to the original value.
TruncatedValue = TruncatedValue.extend(OriginalWidth);
if (llvm::APSInt::isSameValue(Value, TruncatedValue))
return false;
// Special-case bitfields of width 1: booleans are naturally 0/1, and
// therefore don't strictly fit into a signed bitfield of width 1.
if (FieldWidth == 1 && Value == 1)
return false;
std::string PrettyValue = Value.toString(10);
std::string PrettyTrunc = TruncatedValue.toString(10);
S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant)
<< PrettyValue << PrettyTrunc << OriginalInit->getType()
<< Init->getSourceRange();
return true;
}
/// Analyze the given simple or compound assignment for warning-worthy
/// operations.
static void AnalyzeAssignment(Sema &S, BinaryOperator *E) {
// Just recurse on the LHS.
AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
// We want to recurse on the RHS as normal unless we're assigning to
// a bitfield.
if (FieldDecl *Bitfield = E->getLHS()->getSourceBitField()) {
if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(),
E->getOperatorLoc())) {
// Recurse, ignoring any implicit conversions on the RHS.
return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(),
E->getOperatorLoc());
}
}
AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
}
/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion.
static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T,
SourceLocation CContext, unsigned diag,
bool pruneControlFlow = false) {
if (pruneControlFlow) {
S.DiagRuntimeBehavior(E->getExprLoc(), E,
S.PDiag(diag)
<< SourceType << T << E->getSourceRange()
<< SourceRange(CContext));
return;
}
S.Diag(E->getExprLoc(), diag)
<< SourceType << T << E->getSourceRange() << SourceRange(CContext);
}
/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion.
static void DiagnoseImpCast(Sema &S, Expr *E, QualType T,
SourceLocation CContext, unsigned diag,
bool pruneControlFlow = false) {
DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow);
}
/// Diagnose an implicit cast from a literal expression. Does not warn when the
/// cast wouldn't lose information.
void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T,
SourceLocation CContext) {
// Try to convert the literal exactly to an integer. If we can, don't warn.
bool isExact = false;
const llvm::APFloat &Value = FL->getValue();
llvm::APSInt IntegerValue(S.Context.getIntWidth(T),
T->hasUnsignedIntegerRepresentation());
if (Value.convertToInteger(IntegerValue,
llvm::APFloat::rmTowardZero, &isExact)
== llvm::APFloat::opOK && isExact)
return;
// FIXME: Force the precision of the source value down so we don't print
// digits which are usually useless (we don't really care here if we
// truncate a digit by accident in edge cases). Ideally, APFloat::toString
// would automatically print the shortest representation, but it's a bit
// tricky to implement.
SmallString<16> PrettySourceValue;
unsigned precision = llvm::APFloat::semanticsPrecision(Value.getSemantics());
precision = (precision * 59 + 195) / 196;
Value.toString(PrettySourceValue, precision);
SmallString<16> PrettyTargetValue;
if (T->isSpecificBuiltinType(BuiltinType::Bool))
PrettyTargetValue = IntegerValue == 0 ? "false" : "true";
else
IntegerValue.toString(PrettyTargetValue);
S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer)
<< FL->getType() << T.getUnqualifiedType() << PrettySourceValue
<< PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext);
}
std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) {
if (!Range.Width) return "0";
llvm::APSInt ValueInRange = Value;
ValueInRange.setIsSigned(!Range.NonNegative);
ValueInRange = ValueInRange.trunc(Range.Width);
return ValueInRange.toString(10);
}
static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) {
if (!isa<ImplicitCastExpr>(Ex))
return false;
Expr *InnerE = Ex->IgnoreParenImpCasts();
const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr();
const Type *Source =
S.Context.getCanonicalType(InnerE->getType()).getTypePtr();
if (Target->isDependentType())
return false;
const BuiltinType *FloatCandidateBT =
dyn_cast<BuiltinType>(ToBool ? Source : Target);
const Type *BoolCandidateType = ToBool ? Target : Source;
return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) &&
FloatCandidateBT && (FloatCandidateBT->isFloatingPoint()));
}
void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall,
SourceLocation CC) {
unsigned NumArgs = TheCall->getNumArgs();
for (unsigned i = 0; i < NumArgs; ++i) {
Expr *CurrA = TheCall->getArg(i);
if (!IsImplicitBoolFloatConversion(S, CurrA, true))
continue;
bool IsSwapped = ((i > 0) &&
IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false));
IsSwapped |= ((i < (NumArgs - 1)) &&
IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false));
if (IsSwapped) {
// Warn on this floating-point to bool conversion.
DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(),
CurrA->getType(), CC,
diag::warn_impcast_floating_point_to_bool);
}
}
}
void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
SourceLocation CC, bool *ICContext = nullptr) {
if (E->isTypeDependent() || E->isValueDependent()) return;
const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr();
const Type *Target = S.Context.getCanonicalType(T).getTypePtr();
if (Source == Target) return;
if (Target->isDependentType()) return;
// If the conversion context location is invalid don't complain. We also
// don't want to emit a warning if the issue occurs from the expansion of
// a system macro. The problem is that 'getSpellingLoc()' is slow, so we
// delay this check as long as possible. Once we detect we are in that
// scenario, we just return.
if (CC.isInvalid())
return;
// Diagnose implicit casts to bool.
if (Target->isSpecificBuiltinType(BuiltinType::Bool)) {
if (isa<StringLiteral>(E))
// Warn on string literal to bool. Checks for string literals in logical
// and expressions, for instance, assert(0 && "error here"), are
// prevented by a check in AnalyzeImplicitConversions().
return DiagnoseImpCast(S, E, T, CC,
diag::warn_impcast_string_literal_to_bool);
if (isa<ObjCStringLiteral>(E) || isa<ObjCArrayLiteral>(E) ||
isa<ObjCDictionaryLiteral>(E) || isa<ObjCBoxedExpr>(E)) {
// This covers the literal expressions that evaluate to Objective-C
// objects.
return DiagnoseImpCast(S, E, T, CC,
diag::warn_impcast_objective_c_literal_to_bool);
}
if (Source->isPointerType() || Source->canDecayToPointerType()) {
// Warn on pointer to bool conversion that is always true.
S.DiagnoseAlwaysNonNullPointer(E, Expr::NPCK_NotNull, /*IsEqual*/ false,
SourceRange(CC));
}
}
// Strip vector types.
if (isa<VectorType>(Source)) {
if (!isa<VectorType>(Target)) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar);
}
// If the vector cast is cast between two vectors of the same size, it is
// a bitcast, not a conversion.
if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target))
return;
Source = cast<VectorType>(Source)->getElementType().getTypePtr();
Target = cast<VectorType>(Target)->getElementType().getTypePtr();
}
if (auto VecTy = dyn_cast<VectorType>(Target))
Target = VecTy->getElementType().getTypePtr();
// Strip complex types.
if (isa<ComplexType>(Source)) {
if (!isa<ComplexType>(Target)) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar);
}
Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
}
const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source);
const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target);
// If the source is floating point...
if (SourceBT && SourceBT->isFloatingPoint()) {
// ...and the target is floating point...
if (TargetBT && TargetBT->isFloatingPoint()) {
// ...then warn if we're dropping FP rank.
// Builtin FP kinds are ordered by increasing FP rank.
if (SourceBT->getKind() > TargetBT->getKind()) {
// Don't warn about float constants that are precisely
// representable in the target type.
Expr::EvalResult result;
if (E->EvaluateAsRValue(result, S.Context)) {
// Value might be a float, a float vector, or a float complex.
if (IsSameFloatAfterCast(result.Val,
S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
S.Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
return;
}
if (S.SourceMgr.isInSystemMacro(CC))
return;
DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision);
}
return;
}
// If the target is integral, always warn.
if (TargetBT && TargetBT->isInteger()) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
Expr *InnerE = E->IgnoreParenImpCasts();
// We also want to warn on, e.g., "int i = -1.234"
if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE))
if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus)
InnerE = UOp->getSubExpr()->IgnoreParenImpCasts();
if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) {
DiagnoseFloatingLiteralImpCast(S, FL, T, CC);
} else {
DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer);
}
}
// If the target is bool, warn if expr is a function or method call.
if (Target->isSpecificBuiltinType(BuiltinType::Bool) &&
isa<CallExpr>(E)) {
// Check last argument of function call to see if it is an
// implicit cast from a type matching the type the result
// is being cast to.
CallExpr *CEx = cast<CallExpr>(E);
unsigned NumArgs = CEx->getNumArgs();
if (NumArgs > 0) {
Expr *LastA = CEx->getArg(NumArgs - 1);
Expr *InnerE = LastA->IgnoreParenImpCasts();
const Type *InnerType =
S.Context.getCanonicalType(InnerE->getType()).getTypePtr();
if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) {
// Warn on this floating-point to bool conversion
DiagnoseImpCast(S, E, T, CC,
diag::warn_impcast_floating_point_to_bool);
}
}
}
return;
}
if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)
== Expr::NPCK_GNUNull) && !Target->isAnyPointerType()
&& !Target->isBlockPointerType() && !Target->isMemberPointerType()
&& Target->isScalarType() && !Target->isNullPtrType()) {
SourceLocation Loc = E->getSourceRange().getBegin();
if (Loc.isMacroID())
Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first;
if (!Loc.isMacroID() || CC.isMacroID())
S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer)
<< T << clang::SourceRange(CC)
<< FixItHint::CreateReplacement(Loc,
S.getFixItZeroLiteralForType(T, Loc));
}
if (!Source->isIntegerType() || !Target->isIntegerType())
return;
// TODO: remove this early return once the false positives for constant->bool
// in templates, macros, etc, are reduced or removed.
if (Target->isSpecificBuiltinType(BuiltinType::Bool))
return;
IntRange SourceRange = GetExprRange(S.Context, E);
IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target);
if (SourceRange.Width > TargetRange.Width) {
// If the source is a constant, use a default-on diagnostic.
// TODO: this should happen for bitfield stores, too.
llvm::APSInt Value(32);
if (E->isIntegerConstantExpr(Value, S.Context)) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
std::string PrettySourceValue = Value.toString(10);
std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange);
S.DiagRuntimeBehavior(E->getExprLoc(), E,
S.PDiag(diag::warn_impcast_integer_precision_constant)
<< PrettySourceValue << PrettyTargetValue
<< E->getType() << T << E->getSourceRange()
<< clang::SourceRange(CC));
return;
}
// People want to build with -Wshorten-64-to-32 and not -Wconversion.
if (S.SourceMgr.isInSystemMacro(CC))
return;
if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64)
return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32,
/* pruneControlFlow */ true);
return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
}
if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
(!TargetRange.NonNegative && SourceRange.NonNegative &&
SourceRange.Width == TargetRange.Width)) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
unsigned DiagID = diag::warn_impcast_integer_sign;
// Traditionally, gcc has warned about this under -Wsign-compare.
// We also want to warn about it in -Wconversion.
// So if -Wconversion is off, use a completely identical diagnostic
// in the sign-compare group.
// The conditional-checking code will
if (ICContext) {
DiagID = diag::warn_impcast_integer_sign_conditional;
*ICContext = true;
}
return DiagnoseImpCast(S, E, T, CC, DiagID);
}
// Diagnose conversions between different enumeration types.
// In C, we pretend that the type of an EnumConstantDecl is its enumeration
// type, to give us better diagnostics.
QualType SourceType = E->getType();
if (!S.getLangOpts().CPlusPlus) {
if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext());
SourceType = S.Context.getTypeDeclType(Enum);
Source = S.Context.getCanonicalType(SourceType).getTypePtr();
}
}
if (const EnumType *SourceEnum = Source->getAs<EnumType>())
if (const EnumType *TargetEnum = Target->getAs<EnumType>())
if (SourceEnum->getDecl()->hasNameForLinkage() &&
TargetEnum->getDecl()->hasNameForLinkage() &&
SourceEnum != TargetEnum) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
return DiagnoseImpCast(S, E, SourceType, T, CC,
diag::warn_impcast_different_enum_types);
}
return;
}
void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
SourceLocation CC, QualType T);
void CheckConditionalOperand(Sema &S, Expr *E, QualType T,
SourceLocation CC, bool &ICContext) {
E = E->IgnoreParenImpCasts();
if (isa<ConditionalOperator>(E))
return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T);
AnalyzeImplicitConversions(S, E, CC);
if (E->getType() != T)
return CheckImplicitConversion(S, E, T, CC, &ICContext);
return;
}
void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
SourceLocation CC, QualType T) {
AnalyzeImplicitConversions(S, E->getCond(), CC);
bool Suspicious = false;
CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious);
CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious);
// If -Wconversion would have warned about either of the candidates
// for a signedness conversion to the context type...
if (!Suspicious) return;
// ...but it's currently ignored...
if (!S.Diags.isIgnored(diag::warn_impcast_integer_sign_conditional, CC))
return;
// ...then check whether it would have warned about either of the
// candidates for a signedness conversion to the condition type.
if (E->getType() == T) return;
Suspicious = false;
CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(),
E->getType(), CC, &Suspicious);
if (!Suspicious)
CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(),
E->getType(), CC, &Suspicious);
}
/// AnalyzeImplicitConversions - Find and report any interesting
/// implicit conversions in the given expression. There are a couple
/// of competing diagnostics here, -Wconversion and -Wsign-compare.
void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
QualType T = OrigE->getType();
Expr *E = OrigE->IgnoreParenImpCasts();
if (E->isTypeDependent() || E->isValueDependent())
return;
// For conditional operators, we analyze the arguments as if they
// were being fed directly into the output.
if (isa<ConditionalOperator>(E)) {
ConditionalOperator *CO = cast<ConditionalOperator>(E);
CheckConditionalOperator(S, CO, CC, T);
return;
}
// Check implicit argument conversions for function calls.
if (CallExpr *Call = dyn_cast<CallExpr>(E))
CheckImplicitArgumentConversions(S, Call, CC);
// Go ahead and check any implicit conversions we might have skipped.
// The non-canonical typecheck is just an optimization;
// CheckImplicitConversion will filter out dead implicit conversions.
if (E->getType() != T)
CheckImplicitConversion(S, E, T, CC);
// Now continue drilling into this expression.
if (PseudoObjectExpr * POE = dyn_cast<PseudoObjectExpr>(E)) {
if (POE->getResultExpr())
E = POE->getResultExpr();
}
if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E))
return AnalyzeImplicitConversions(S, OVE->getSourceExpr(), CC);
// Skip past explicit casts.
if (isa<ExplicitCastExpr>(E)) {
E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();
return AnalyzeImplicitConversions(S, E, CC);
}
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
// Do a somewhat different check with comparison operators.
if (BO->isComparisonOp())
return AnalyzeComparison(S, BO);
// And with simple assignments.
if (BO->getOpcode() == BO_Assign)
return AnalyzeAssignment(S, BO);
}
// These break the otherwise-useful invariant below. Fortunately,
// we don't really need to recurse into them, because any internal
// expressions should have been analyzed already when they were
// built into statements.
if (isa<StmtExpr>(E)) return;
// Don't descend into unevaluated contexts.
if (isa<UnaryExprOrTypeTraitExpr>(E)) return;
// Now just recurse over the expression's children.
CC = E->getExprLoc();
BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
bool IsLogicalAndOperator = BO && BO->getOpcode() == BO_LAnd;
for (Stmt::child_range I = E->children(); I; ++I) {
Expr *ChildExpr = dyn_cast_or_null<Expr>(*I);
if (!ChildExpr)
continue;
if (IsLogicalAndOperator &&
isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
// Ignore checking string literals that are in logical and operators.
// This is a common pattern for asserts.
continue;
AnalyzeImplicitConversions(S, ChildExpr, CC);
}
}
} // end anonymous namespace
enum {
AddressOf,
FunctionPointer,
ArrayPointer
};
// Helper function for Sema::DiagnoseAlwaysNonNullPointer.
// Returns true when emitting a warning about taking the address of a reference.
static bool CheckForReference(Sema &SemaRef, const Expr *E,
PartialDiagnostic PD) {
E = E->IgnoreParenImpCasts();
const FunctionDecl *FD = nullptr;
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
if (!DRE->getDecl()->getType()->isReferenceType())
return false;
} else if (const MemberExpr *M = dyn_cast<MemberExpr>(E)) {
if (!M->getMemberDecl()->getType()->isReferenceType())
return false;
} else if (const CallExpr *Call = dyn_cast<CallExpr>(E)) {
if (!Call->getCallReturnType()->isReferenceType())
return false;
FD = Call->getDirectCallee();
} else {
return false;
}
SemaRef.Diag(E->getExprLoc(), PD);
// If possible, point to location of function.
if (FD) {
SemaRef.Diag(FD->getLocation(), diag::note_reference_is_return_value) << FD;
}
return true;
}
/// \brief Diagnose pointers that are always non-null.
/// \param E the expression containing the pointer
/// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is
/// compared to a null pointer
/// \param IsEqual True when the comparison is equal to a null pointer
/// \param Range Extra SourceRange to highlight in the diagnostic
void Sema::DiagnoseAlwaysNonNullPointer(Expr *E,
Expr::NullPointerConstantKind NullKind,
bool IsEqual, SourceRange Range) {
if (!E)
return;
// Don't warn inside macros.
if (E->getExprLoc().isMacroID())
return;
E = E->IgnoreImpCasts();
const bool IsCompare = NullKind != Expr::NPCK_NotNull;
if (isa<CXXThisExpr>(E)) {
unsigned DiagID = IsCompare ? diag::warn_this_null_compare
: diag::warn_this_bool_conversion;
Diag(E->getExprLoc(), DiagID) << E->getSourceRange() << Range << IsEqual;
return;
}
bool IsAddressOf = false;
if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
if (UO->getOpcode() != UO_AddrOf)
return;
IsAddressOf = true;
E = UO->getSubExpr();
}
if (IsAddressOf) {
unsigned DiagID = IsCompare
? diag::warn_address_of_reference_null_compare
: diag::warn_address_of_reference_bool_conversion;
PartialDiagnostic PD = PDiag(DiagID) << E->getSourceRange() << Range
<< IsEqual;
if (CheckForReference(*this, E, PD)) {
return;
}
}
// Expect to find a single Decl. Skip anything more complicated.
ValueDecl *D = nullptr;
if (DeclRefExpr *R = dyn_cast<DeclRefExpr>(E)) {
D = R->getDecl();
} else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) {
D = M->getMemberDecl();
}
// Weak Decls can be null.
if (!D || D->isWeak())
return;
QualType T = D->getType();
const bool IsArray = T->isArrayType();
const bool IsFunction = T->isFunctionType();
// Address of function is used to silence the function warning.
if (IsAddressOf && IsFunction) {
return;
}
// Found nothing.
if (!IsAddressOf && !IsFunction && !IsArray)
return;
// Pretty print the expression for the diagnostic.
std::string Str;
llvm::raw_string_ostream S(Str);
E->printPretty(S, nullptr, getPrintingPolicy());
unsigned DiagID = IsCompare ? diag::warn_null_pointer_compare
: diag::warn_impcast_pointer_to_bool;
unsigned DiagType;
if (IsAddressOf)
DiagType = AddressOf;
else if (IsFunction)
DiagType = FunctionPointer;
else if (IsArray)
DiagType = ArrayPointer;
else
llvm_unreachable("Could not determine diagnostic.");
Diag(E->getExprLoc(), DiagID) << DiagType << S.str() << E->getSourceRange()
<< Range << IsEqual;
if (!IsFunction)
return;
// Suggest '&' to silence the function warning.
Diag(E->getExprLoc(), diag::note_function_warning_silence)
<< FixItHint::CreateInsertion(E->getLocStart(), "&");
// Check to see if '()' fixit should be emitted.
QualType ReturnType;
UnresolvedSet<4> NonTemplateOverloads;
tryExprAsCall(*E, ReturnType, NonTemplateOverloads);
if (ReturnType.isNull())
return;
if (IsCompare) {
// There are two cases here. If there is null constant, the only suggest
// for a pointer return type. If the null is 0, then suggest if the return
// type is a pointer or an integer type.
if (!ReturnType->isPointerType()) {
if (NullKind == Expr::NPCK_ZeroExpression ||
NullKind == Expr::NPCK_ZeroLiteral) {
if (!ReturnType->isIntegerType())
return;
} else {
return;
}
}
} else { // !IsCompare
// For function to bool, only suggest if the function pointer has bool
// return type.
if (!ReturnType->isSpecificBuiltinType(BuiltinType::Bool))
return;
}
Diag(E->getExprLoc(), diag::note_function_to_function_call)
<< FixItHint::CreateInsertion(getLocForEndOfToken(E->getLocEnd()), "()");
}
/// Diagnoses "dangerous" implicit conversions within the given
/// expression (which is a full expression). Implements -Wconversion
/// and -Wsign-compare.
///
/// \param CC the "context" location of the implicit conversion, i.e.
/// the most location of the syntactic entity requiring the implicit
/// conversion
void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) {
// Don't diagnose in unevaluated contexts.
if (isUnevaluatedContext())
return;
// Don't diagnose for value- or type-dependent expressions.
if (E->isTypeDependent() || E->isValueDependent())
return;
// Check for array bounds violations in cases where the check isn't triggered
// elsewhere for other Expr types (like BinaryOperators), e.g. when an
// ArraySubscriptExpr is on the RHS of a variable initialization.
CheckArrayAccess(E);
// This is not the right CC for (e.g.) a variable initialization.
AnalyzeImplicitConversions(*this, E, CC);
}
/// Diagnose when expression is an integer constant expression and its evaluation
/// results in integer overflow
void Sema::CheckForIntOverflow (Expr *E) {
if (isa<BinaryOperator>(E->IgnoreParens()))
E->EvaluateForOverflow(Context);
}
namespace {
/// \brief Visitor for expressions which looks for unsequenced operations on the
/// same object.
class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> {
typedef EvaluatedExprVisitor<SequenceChecker> Base;
/// \brief A tree of sequenced regions within an expression. Two regions are
/// unsequenced if one is an ancestor or a descendent of the other. When we
/// finish processing an expression with sequencing, such as a comma
/// expression, we fold its tree nodes into its parent, since they are
/// unsequenced with respect to nodes we will visit later.
class SequenceTree {
struct Value {
explicit Value(unsigned Parent) : Parent(Parent), Merged(false) {}
unsigned Parent : 31;
bool Merged : 1;
};
SmallVector<Value, 8> Values;
public:
/// \brief A region within an expression which may be sequenced with respect
/// to some other region.
class Seq {
explicit Seq(unsigned N) : Index(N) {}
unsigned Index;
friend class SequenceTree;
public:
Seq() : Index(0) {}
};
SequenceTree() { Values.push_back(Value(0)); }
Seq root() const { return Seq(0); }
/// \brief Create a new sequence of operations, which is an unsequenced
/// subset of \p Parent. This sequence of operations is sequenced with
/// respect to other children of \p Parent.
Seq allocate(Seq Parent) {
Values.push_back(Value(Parent.Index));
return Seq(Values.size() - 1);
}
/// \brief Merge a sequence of operations into its parent.
void merge(Seq S) {
Values[S.Index].Merged = true;
}
/// \brief Determine whether two operations are unsequenced. This operation
/// is asymmetric: \p Cur should be the more recent sequence, and \p Old
/// should have been merged into its parent as appropriate.
bool isUnsequenced(Seq Cur, Seq Old) {
unsigned C = representative(Cur.Index);
unsigned Target = representative(Old.Index);
while (C >= Target) {
if (C == Target)
return true;
C = Values[C].Parent;
}
return false;
}
private:
/// \brief Pick a representative for a sequence.
unsigned representative(unsigned K) {
if (Values[K].Merged)
// Perform path compression as we go.
return Values[K].Parent = representative(Values[K].Parent);
return K;
}
};
/// An object for which we can track unsequenced uses.
typedef NamedDecl *Object;
/// Different flavors of object usage which we track. We only track the
/// least-sequenced usage of each kind.
enum UsageKind {
/// A read of an object. Multiple unsequenced reads are OK.
UK_Use,
/// A modification of an object which is sequenced before the value
/// computation of the expression, such as ++n in C++.
UK_ModAsValue,
/// A modification of an object which is not sequenced before the value
/// computation of the expression, such as n++.
UK_ModAsSideEffect,
UK_Count = UK_ModAsSideEffect + 1
};
struct Usage {
Usage() : Use(nullptr), Seq() {}
Expr *Use;
SequenceTree::Seq Seq;
};
struct UsageInfo {
UsageInfo() : Diagnosed(false) {}
Usage Uses[UK_Count];
/// Have we issued a diagnostic for this variable already?
bool Diagnosed;
};
typedef llvm::SmallDenseMap<Object, UsageInfo, 16> UsageInfoMap;
Sema &SemaRef;
/// Sequenced regions within the expression.
SequenceTree Tree;
/// Declaration modifications and references which we have seen.
UsageInfoMap UsageMap;
/// The region we are currently within.
SequenceTree::Seq Region;
/// Filled in with declarations which were modified as a side-effect
/// (that is, post-increment operations).
SmallVectorImpl<std::pair<Object, Usage> > *ModAsSideEffect;
/// Expressions to check later. We defer checking these to reduce
/// stack usage.
SmallVectorImpl<Expr *> &WorkList;
/// RAII object wrapping the visitation of a sequenced subexpression of an
/// expression. At the end of this process, the side-effects of the evaluation
/// become sequenced with respect to the value computation of the result, so
/// we downgrade any UK_ModAsSideEffect within the evaluation to
/// UK_ModAsValue.
struct SequencedSubexpression {
SequencedSubexpression(SequenceChecker &Self)
: Self(Self), OldModAsSideEffect(Self.ModAsSideEffect) {
Self.ModAsSideEffect = &ModAsSideEffect;
}
~SequencedSubexpression() {
for (unsigned I = 0, E = ModAsSideEffect.size(); I != E; ++I) {
UsageInfo &U = Self.UsageMap[ModAsSideEffect[I].first];
U.Uses[UK_ModAsSideEffect] = ModAsSideEffect[I].second;
Self.addUsage(U, ModAsSideEffect[I].first,
ModAsSideEffect[I].second.Use, UK_ModAsValue);
}
Self.ModAsSideEffect = OldModAsSideEffect;
}
SequenceChecker &Self;
SmallVector<std::pair<Object, Usage>, 4> ModAsSideEffect;
SmallVectorImpl<std::pair<Object, Usage> > *OldModAsSideEffect;
};
/// RAII object wrapping the visitation of a subexpression which we might
/// choose to evaluate as a constant. If any subexpression is evaluated and
/// found to be non-constant, this allows us to suppress the evaluation of
/// the outer expression.
class EvaluationTracker {
public:
EvaluationTracker(SequenceChecker &Self)
: Self(Self), Prev(Self.EvalTracker), EvalOK(true) {
Self.EvalTracker = this;
}
~EvaluationTracker() {
Self.EvalTracker = Prev;
if (Prev)
Prev->EvalOK &= EvalOK;
}
bool evaluate(const Expr *E, bool &Result) {
if (!EvalOK || E->isValueDependent())
return false;
EvalOK = E->EvaluateAsBooleanCondition(Result, Self.SemaRef.Context);
return EvalOK;
}
private:
SequenceChecker &Self;
EvaluationTracker *Prev;
bool EvalOK;
} *EvalTracker;
/// \brief Find the object which is produced by the specified expression,
/// if any.
Object getObject(Expr *E, bool Mod) const {
E = E->IgnoreParenCasts();
if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
if (Mod && (UO->getOpcode() == UO_PreInc || UO->getOpcode() == UO_PreDec))
return getObject(UO->getSubExpr(), Mod);
} else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
if (BO->getOpcode() == BO_Comma)
return getObject(BO->getRHS(), Mod);
if (Mod && BO->isAssignmentOp())
return getObject(BO->getLHS(), Mod);
} else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
// FIXME: Check for more interesting cases, like "x.n = ++x.n".
if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenCasts()))
return ME->getMemberDecl();
} else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
// FIXME: If this is a reference, map through to its value.
return DRE->getDecl();
return nullptr;
}
/// \brief Note that an object was modified or used by an expression.
void addUsage(UsageInfo &UI, Object O, Expr *Ref, UsageKind UK) {
Usage &U = UI.Uses[UK];
if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) {
if (UK == UK_ModAsSideEffect && ModAsSideEffect)
ModAsSideEffect->push_back(std::make_pair(O, U));
U.Use = Ref;
U.Seq = Region;
}
}
/// \brief Check whether a modification or use conflicts with a prior usage.
void checkUsage(Object O, UsageInfo &UI, Expr *Ref, UsageKind OtherKind,
bool IsModMod) {
if (UI.Diagnosed)
return;
const Usage &U = UI.Uses[OtherKind];
if (!U.Use || !Tree.isUnsequenced(Region, U.Seq))
return;
Expr *Mod = U.Use;
Expr *ModOrUse = Ref;
if (OtherKind == UK_Use)
std::swap(Mod, ModOrUse);
SemaRef.Diag(Mod->getExprLoc(),
IsModMod ? diag::warn_unsequenced_mod_mod
: diag::warn_unsequenced_mod_use)
<< O << SourceRange(ModOrUse->getExprLoc());
UI.Diagnosed = true;
}
void notePreUse(Object O, Expr *Use) {
UsageInfo &U = UsageMap[O];
// Uses conflict with other modifications.
checkUsage(O, U, Use, UK_ModAsValue, false);
}
void notePostUse(Object O, Expr *Use) {
UsageInfo &U = UsageMap[O];
checkUsage(O, U, Use, UK_ModAsSideEffect, false);
addUsage(U, O, Use, UK_Use);
}
void notePreMod(Object O, Expr *Mod) {
UsageInfo &U = UsageMap[O];
// Modifications conflict with other modifications and with uses.
checkUsage(O, U, Mod, UK_ModAsValue, true);
checkUsage(O, U, Mod, UK_Use, false);
}
void notePostMod(Object O, Expr *Use, UsageKind UK) {
UsageInfo &U = UsageMap[O];
checkUsage(O, U, Use, UK_ModAsSideEffect, true);
addUsage(U, O, Use, UK);
}
public:
SequenceChecker(Sema &S, Expr *E, SmallVectorImpl<Expr *> &WorkList)
: Base(S.Context), SemaRef(S), Region(Tree.root()),
ModAsSideEffect(nullptr), WorkList(WorkList), EvalTracker(nullptr) {
Visit(E);
}
void VisitStmt(Stmt *S) {
// Skip all statements which aren't expressions for now.
}
void VisitExpr(Expr *E) {
// By default, just recurse to evaluated subexpressions.
Base::VisitStmt(E);
}
void VisitCastExpr(CastExpr *E) {
Object O = Object();
if (E->getCastKind() == CK_LValueToRValue)
O = getObject(E->getSubExpr(), false);
if (O)
notePreUse(O, E);
VisitExpr(E);
if (O)
notePostUse(O, E);
}
void VisitBinComma(BinaryOperator *BO) {
// C++11 [expr.comma]p1:
// Every value computation and side effect associated with the left
// expression is sequenced before every value computation and side
// effect associated with the right expression.
SequenceTree::Seq LHS = Tree.allocate(Region);
SequenceTree::Seq RHS = Tree.allocate(Region);
SequenceTree::Seq OldRegion = Region;
{
SequencedSubexpression SeqLHS(*this);
Region = LHS;
Visit(BO->getLHS());
}
Region = RHS;
Visit(BO->getRHS());
Region = OldRegion;
// Forget that LHS and RHS are sequenced. They are both unsequenced
// with respect to other stuff.
Tree.merge(LHS);
Tree.merge(RHS);
}
void VisitBinAssign(BinaryOperator *BO) {
// The modification is sequenced after the value computation of the LHS
// and RHS, so check it before inspecting the operands and update the
// map afterwards.
Object O = getObject(BO->getLHS(), true);
if (!O)
return VisitExpr(BO);
notePreMod(O, BO);
// C++11 [expr.ass]p7:
// E1 op= E2 is equivalent to E1 = E1 op E2, except that E1 is evaluated
// only once.
//
// Therefore, for a compound assignment operator, O is considered used
// everywhere except within the evaluation of E1 itself.
if (isa<CompoundAssignOperator>(BO))
notePreUse(O, BO);
Visit(BO->getLHS());
if (isa<CompoundAssignOperator>(BO))
notePostUse(O, BO);
Visit(BO->getRHS());
// C++11 [expr.ass]p1:
// the assignment is sequenced [...] before the value computation of the
// assignment expression.
// C11 6.5.16/3 has no such rule.
notePostMod(O, BO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue
: UK_ModAsSideEffect);
}
void VisitCompoundAssignOperator(CompoundAssignOperator *CAO) {
VisitBinAssign(CAO);
}
void VisitUnaryPreInc(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); }
void VisitUnaryPreDec(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); }
void VisitUnaryPreIncDec(UnaryOperator *UO) {
Object O = getObject(UO->getSubExpr(), true);
if (!O)
return VisitExpr(UO);
notePreMod(O, UO);
Visit(UO->getSubExpr());
// C++11 [expr.pre.incr]p1:
// the expression ++x is equivalent to x+=1
notePostMod(O, UO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue
: UK_ModAsSideEffect);
}
void VisitUnaryPostInc(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); }
void VisitUnaryPostDec(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); }
void VisitUnaryPostIncDec(UnaryOperator *UO) {
Object O = getObject(UO->getSubExpr(), true);
if (!O)
return VisitExpr(UO);
notePreMod(O, UO);
Visit(UO->getSubExpr());
notePostMod(O, UO, UK_ModAsSideEffect);
}
/// Don't visit the RHS of '&&' or '||' if it might not be evaluated.
void VisitBinLOr(BinaryOperator *BO) {
// The side-effects of the LHS of an '&&' are sequenced before the
// value computation of the RHS, and hence before the value computation
// of the '&&' itself, unless the LHS evaluates to zero. We treat them
// as if they were unconditionally sequenced.
EvaluationTracker Eval(*this);
{
SequencedSubexpression Sequenced(*this);
Visit(BO->getLHS());
}
bool Result;
if (Eval.evaluate(BO->getLHS(), Result)) {
if (!Result)
Visit(BO->getRHS());
} else {
// Check for unsequenced operations in the RHS, treating it as an
// entirely separate evaluation.
//
// FIXME: If there are operations in the RHS which are unsequenced
// with respect to operations outside the RHS, and those operations
// are unconditionally evaluated, diagnose them.
WorkList.push_back(BO->getRHS());
}
}
void VisitBinLAnd(BinaryOperator *BO) {
EvaluationTracker Eval(*this);
{
SequencedSubexpression Sequenced(*this);
Visit(BO->getLHS());
}
bool Result;
if (Eval.evaluate(BO->getLHS(), Result)) {
if (Result)
Visit(BO->getRHS());
} else {
WorkList.push_back(BO->getRHS());
}
}
// Only visit the condition, unless we can be sure which subexpression will
// be chosen.
void VisitAbstractConditionalOperator(AbstractConditionalOperator *CO) {
EvaluationTracker Eval(*this);
{
SequencedSubexpression Sequenced(*this);
Visit(CO->getCond());
}
bool Result;
if (Eval.evaluate(CO->getCond(), Result))
Visit(Result ? CO->getTrueExpr() : CO->getFalseExpr());
else {
WorkList.push_back(CO->getTrueExpr());
WorkList.push_back(CO->getFalseExpr());
}
}
void VisitCallExpr(CallExpr *CE) {
// C++11 [intro.execution]p15:
// When calling a function [...], every value computation and side effect
// associated with any argument expression, or with the postfix expression
// designating the called function, is sequenced before execution of every
// expression or statement in the body of the function [and thus before
// the value computation of its result].
SequencedSubexpression Sequenced(*this);
Base::VisitCallExpr(CE);
// FIXME: CXXNewExpr and CXXDeleteExpr implicitly call functions.
}
void VisitCXXConstructExpr(CXXConstructExpr *CCE) {
// This is a call, so all subexpressions are sequenced before the result.
SequencedSubexpression Sequenced(*this);
if (!CCE->isListInitialization())
return VisitExpr(CCE);
// In C++11, list initializations are sequenced.
SmallVector<SequenceTree::Seq, 32> Elts;
SequenceTree::Seq Parent = Region;
for (CXXConstructExpr::arg_iterator I = CCE->arg_begin(),
E = CCE->arg_end();
I != E; ++I) {
Region = Tree.allocate(Parent);
Elts.push_back(Region);
Visit(*I);
}
// Forget that the initializers are sequenced.
Region = Parent;
for (unsigned I = 0; I < Elts.size(); ++I)
Tree.merge(Elts[I]);
}
void VisitInitListExpr(InitListExpr *ILE) {
if (!SemaRef.getLangOpts().CPlusPlus11)
return VisitExpr(ILE);
// In C++11, list initializations are sequenced.
SmallVector<SequenceTree::Seq, 32> Elts;
SequenceTree::Seq Parent = Region;
for (unsigned I = 0; I < ILE->getNumInits(); ++I) {
Expr *E = ILE->getInit(I);
if (!E) continue;
Region = Tree.allocate(Parent);
Elts.push_back(Region);
Visit(E);
}
// Forget that the initializers are sequenced.
Region = Parent;
for (unsigned I = 0; I < Elts.size(); ++I)
Tree.merge(Elts[I]);
}
};
}
void Sema::CheckUnsequencedOperations(Expr *E) {
SmallVector<Expr *, 8> WorkList;
WorkList.push_back(E);
while (!WorkList.empty()) {
Expr *Item = WorkList.pop_back_val();
SequenceChecker(*this, Item, WorkList);
}
}
void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc,
bool IsConstexpr) {
CheckImplicitConversions(E, CheckLoc);
CheckUnsequencedOperations(E);
if (!IsConstexpr && !E->isValueDependent())
CheckForIntOverflow(E);
}
void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
FieldDecl *BitField,
Expr *Init) {
(void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc);
}
/// CheckParmsForFunctionDef - Check that the parameters of the given
/// function are appropriate for the definition of a function. This
/// takes care of any checks that cannot be performed on the
/// declaration itself, e.g., that the types of each of the function
/// parameters are complete.
bool Sema::CheckParmsForFunctionDef(ParmVarDecl *const *P,
ParmVarDecl *const *PEnd,
bool CheckParameterNames) {
bool HasInvalidParm = false;
for (; P != PEnd; ++P) {
ParmVarDecl *Param = *P;
// C99 6.7.5.3p4: the parameters in a parameter type list in a
// function declarator that is part of a function definition of
// that function shall not have incomplete type.
//
// This is also C++ [dcl.fct]p6.
if (!Param->isInvalidDecl() &&
RequireCompleteType(Param->getLocation(), Param->getType(),
diag::err_typecheck_decl_incomplete_type)) {
Param->setInvalidDecl();
HasInvalidParm = true;
}
// C99 6.9.1p5: If the declarator includes a parameter type list, the
// declaration of each parameter shall include an identifier.
if (CheckParameterNames &&
Param->getIdentifier() == nullptr &&
!Param->isImplicit() &&
!getLangOpts().CPlusPlus)
Diag(Param->getLocation(), diag::err_parameter_name_omitted);
// C99 6.7.5.3p12:
// If the function declarator is not part of a definition of that
// function, parameters may have incomplete type and may use the [*]
// notation in their sequences of declarator specifiers to specify
// variable length array types.
QualType PType = Param->getOriginalType();
while (const ArrayType *AT = Context.getAsArrayType(PType)) {
if (AT->getSizeModifier() == ArrayType::Star) {
// FIXME: This diagnostic should point the '[*]' if source-location
// information is added for it.
Diag(Param->getLocation(), diag::err_array_star_in_function_definition);
break;
}
PType= AT->getElementType();
}
// MSVC destroys objects passed by value in the callee. Therefore a
// function definition which takes such a parameter must be able to call the
// object's destructor. However, we don't perform any direct access check
// on the dtor.
if (getLangOpts().CPlusPlus && Context.getTargetInfo()
.getCXXABI()
.areArgsDestroyedLeftToRightInCallee()) {
if (!Param->isInvalidDecl()) {
if (const RecordType *RT = Param->getType()->getAs<RecordType>()) {
CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
if (!ClassDecl->isInvalidDecl() &&
!ClassDecl->hasIrrelevantDestructor() &&
!ClassDecl->isDependentContext()) {
CXXDestructorDecl *Destructor = LookupDestructor(ClassDecl);
MarkFunctionReferenced(Param->getLocation(), Destructor);
DiagnoseUseOfDecl(Destructor, Param->getLocation());
}
}
}
}
}
return HasInvalidParm;
}
/// CheckCastAlign - Implements -Wcast-align, which warns when a
/// pointer cast increases the alignment requirements.
void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) {
// This is actually a lot of work to potentially be doing on every
// cast; don't do it if we're ignoring -Wcast_align (as is the default).
if (getDiagnostics().isIgnored(diag::warn_cast_align, TRange.getBegin()))
return;
// Ignore dependent types.
if (T->isDependentType() || Op->getType()->isDependentType())
return;
// Require that the destination be a pointer type.
const PointerType *DestPtr = T->getAs<PointerType>();
if (!DestPtr) return;
// If the destination has alignment 1, we're done.
QualType DestPointee = DestPtr->getPointeeType();
if (DestPointee->isIncompleteType()) return;
CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee);
if (DestAlign.isOne()) return;
// Require that the source be a pointer type.
const PointerType *SrcPtr = Op->getType()->getAs<PointerType>();
if (!SrcPtr) return;
QualType SrcPointee = SrcPtr->getPointeeType();
// Whitelist casts from cv void*. We already implicitly
// whitelisted casts to cv void*, since they have alignment 1.
// Also whitelist casts involving incomplete types, which implicitly
// includes 'void'.
if (SrcPointee->isIncompleteType()) return;
CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee);
if (SrcAlign >= DestAlign) return;
Diag(TRange.getBegin(), diag::warn_cast_align)
<< Op->getType() << T
<< static_cast<unsigned>(SrcAlign.getQuantity())
<< static_cast<unsigned>(DestAlign.getQuantity())
<< TRange << Op->getSourceRange();
}
static const Type* getElementType(const Expr *BaseExpr) {
const Type* EltType = BaseExpr->getType().getTypePtr();
if (EltType->isAnyPointerType())
return EltType->getPointeeType().getTypePtr();
else if (EltType->isArrayType())
return EltType->getBaseElementTypeUnsafe();
return EltType;
}
/// \brief Check whether this array fits the idiom of a size-one tail padded
/// array member of a struct.
///
/// We avoid emitting out-of-bounds access warnings for such arrays as they are
/// commonly used to emulate flexible arrays in C89 code.
static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size,
const NamedDecl *ND) {
if (Size != 1 || !ND) return false;
const FieldDecl *FD = dyn_cast<FieldDecl>(ND);
if (!FD) return false;
// Don't consider sizes resulting from macro expansions or template argument
// substitution to form C89 tail-padded arrays.
TypeSourceInfo *TInfo = FD->getTypeSourceInfo();
while (TInfo) {
TypeLoc TL = TInfo->getTypeLoc();
// Look through typedefs.
if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) {
const TypedefNameDecl *TDL = TTL.getTypedefNameDecl();
TInfo = TDL->getTypeSourceInfo();
continue;
}
if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) {
const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr());
if (!SizeExpr || SizeExpr->getExprLoc().isMacroID())
return false;
}
break;
}
const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext());
if (!RD) return false;
if (RD->isUnion()) return false;
if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
if (!CRD->isStandardLayout()) return false;
}
// See if this is the last field decl in the record.
const Decl *D = FD;
while ((D = D->getNextDeclInContext()))
if (isa<FieldDecl>(D))
return false;
return true;
}
void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
const ArraySubscriptExpr *ASE,
bool AllowOnePastEnd, bool IndexNegated) {
IndexExpr = IndexExpr->IgnoreParenImpCasts();
if (IndexExpr->isValueDependent())
return;
const Type *EffectiveType = getElementType(BaseExpr);
BaseExpr = BaseExpr->IgnoreParenCasts();
const ConstantArrayType *ArrayTy =
Context.getAsConstantArrayType(BaseExpr->getType());
if (!ArrayTy)
return;
llvm::APSInt index;
if (!IndexExpr->EvaluateAsInt(index, Context))
return;
if (IndexNegated)
index = -index;
const NamedDecl *ND = nullptr;
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
ND = dyn_cast<NamedDecl>(DRE->getDecl());
if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
if (index.isUnsigned() || !index.isNegative()) {
llvm::APInt size = ArrayTy->getSize();
if (!size.isStrictlyPositive())
return;
const Type* BaseType = getElementType(BaseExpr);
if (BaseType != EffectiveType) {
// Make sure we're comparing apples to apples when comparing index to size
uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType);
uint64_t array_typesize = Context.getTypeSize(BaseType);
// Handle ptrarith_typesize being zero, such as when casting to void*
if (!ptrarith_typesize) ptrarith_typesize = 1;
if (ptrarith_typesize != array_typesize) {
// There's a cast to a different size type involved
uint64_t ratio = array_typesize / ptrarith_typesize;
// TODO: Be smarter about handling cases where array_typesize is not a
// multiple of ptrarith_typesize
if (ptrarith_typesize * ratio == array_typesize)
size *= llvm::APInt(size.getBitWidth(), ratio);
}
}
if (size.getBitWidth() > index.getBitWidth())
index = index.zext(size.getBitWidth());
else if (size.getBitWidth() < index.getBitWidth())
size = size.zext(index.getBitWidth());
// For array subscripting the index must be less than size, but for pointer
// arithmetic also allow the index (offset) to be equal to size since
// computing the next address after the end of the array is legal and
// commonly done e.g. in C++ iterators and range-based for loops.
if (AllowOnePastEnd ? index.ule(size) : index.ult(size))
return;
// Also don't warn for arrays of size 1 which are members of some
// structure. These are often used to approximate flexible arrays in C89
// code.
if (IsTailPaddedMemberArray(*this, size, ND))
return;
// Suppress the warning if the subscript expression (as identified by the
// ']' location) and the index expression are both from macro expansions
// within a system header.
if (ASE) {
SourceLocation RBracketLoc = SourceMgr.getSpellingLoc(
ASE->getRBracketLoc());
if (SourceMgr.isInSystemHeader(RBracketLoc)) {
SourceLocation IndexLoc = SourceMgr.getSpellingLoc(
IndexExpr->getLocStart());
if (SourceMgr.isWrittenInSameFile(RBracketLoc, IndexLoc))
return;
}
}
unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds;
if (ASE)
DiagID = diag::warn_array_index_exceeds_bounds;
DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
PDiag(DiagID) << index.toString(10, true)
<< size.toString(10, true)
<< (unsigned)size.getLimitedValue(~0U)
<< IndexExpr->getSourceRange());
} else {
unsigned DiagID = diag::warn_array_index_precedes_bounds;
if (!ASE) {
DiagID = diag::warn_ptr_arith_precedes_bounds;
if (index.isNegative()) index = -index;
}
DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
PDiag(DiagID) << index.toString(10, true)
<< IndexExpr->getSourceRange());
}
if (!ND) {
// Try harder to find a NamedDecl to point at in the note.
while (const ArraySubscriptExpr *ASE =
dyn_cast<ArraySubscriptExpr>(BaseExpr))
BaseExpr = ASE->getBase()->IgnoreParenCasts();
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
ND = dyn_cast<NamedDecl>(DRE->getDecl());
if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
}
if (ND)
DiagRuntimeBehavior(ND->getLocStart(), BaseExpr,
PDiag(diag::note_array_index_out_of_bounds)
<< ND->getDeclName());
}
void Sema::CheckArrayAccess(const Expr *expr) {
int AllowOnePastEnd = 0;
while (expr) {
expr = expr->IgnoreParenImpCasts();
switch (expr->getStmtClass()) {
case Stmt::ArraySubscriptExprClass: {
const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr);
CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE,
AllowOnePastEnd > 0);
return;
}
case Stmt::UnaryOperatorClass: {
// Only unwrap the * and & unary operators
const UnaryOperator *UO = cast<UnaryOperator>(expr);
expr = UO->getSubExpr();
switch (UO->getOpcode()) {
case UO_AddrOf:
AllowOnePastEnd++;
break;
case UO_Deref:
AllowOnePastEnd--;
break;
default:
return;
}
break;
}
case Stmt::ConditionalOperatorClass: {
const ConditionalOperator *cond = cast<ConditionalOperator>(expr);
if (const Expr *lhs = cond->getLHS())
CheckArrayAccess(lhs);
if (const Expr *rhs = cond->getRHS())
CheckArrayAccess(rhs);
return;
}
default:
return;
}
}
}
//===--- CHECK: Objective-C retain cycles ----------------------------------//
namespace {
struct RetainCycleOwner {
RetainCycleOwner() : Variable(nullptr), Indirect(false) {}
VarDecl *Variable;
SourceRange Range;
SourceLocation Loc;
bool Indirect;
void setLocsFrom(Expr *e) {
Loc = e->getExprLoc();
Range = e->getSourceRange();
}
};
}
/// Consider whether capturing the given variable can possibly lead to
/// a retain cycle.
static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) {
// In ARC, it's captured strongly iff the variable has __strong
// lifetime. In MRR, it's captured strongly if the variable is
// __block and has an appropriate type.
if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
return false;
owner.Variable = var;
if (ref)
owner.setLocsFrom(ref);
return true;
}
static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) {
while (true) {
e = e->IgnoreParens();
if (CastExpr *cast = dyn_cast<CastExpr>(e)) {
switch (cast->getCastKind()) {
case CK_BitCast:
case CK_LValueBitCast:
case CK_LValueToRValue:
case CK_ARCReclaimReturnedObject:
e = cast->getSubExpr();
continue;
default:
return false;
}
}
if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) {
ObjCIvarDecl *ivar = ref->getDecl();
if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
return false;
// Try to find a retain cycle in the base.
if (!findRetainCycleOwner(S, ref->getBase(), owner))
return false;
if (ref->isFreeIvar()) owner.setLocsFrom(ref);
owner.Indirect = true;
return true;
}
if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) {
VarDecl *var = dyn_cast<VarDecl>(ref->getDecl());
if (!var) return false;
return considerVariable(var, ref, owner);
}
if (MemberExpr *member = dyn_cast<MemberExpr>(e)) {
if (member->isArrow()) return false;
// Don't count this as an indirect ownership.
e = member->getBase();
continue;
}
if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
// Only pay attention to pseudo-objects on property references.
ObjCPropertyRefExpr *pre
= dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm()
->IgnoreParens());
if (!pre) return false;
if (pre->isImplicitProperty()) return false;
ObjCPropertyDecl *property = pre->getExplicitProperty();
if (!property->isRetaining() &&
!(property->getPropertyIvarDecl() &&
property->getPropertyIvarDecl()->getType()
.getObjCLifetime() == Qualifiers::OCL_Strong))
return false;
owner.Indirect = true;
if (pre->isSuperReceiver()) {
owner.Variable = S.getCurMethodDecl()->getSelfDecl();
if (!owner.Variable)
return false;
owner.Loc = pre->getLocation();
owner.Range = pre->getSourceRange();
return true;
}
e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase())
->getSourceExpr());
continue;
}
// Array ivars?
return false;
}
}
namespace {
struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> {
FindCaptureVisitor(ASTContext &Context, VarDecl *variable)
: EvaluatedExprVisitor<FindCaptureVisitor>(Context),
Context(Context), Variable(variable), Capturer(nullptr),
VarWillBeReased(false) {}
ASTContext &Context;
VarDecl *Variable;
Expr *Capturer;
bool VarWillBeReased;
void VisitDeclRefExpr(DeclRefExpr *ref) {
if (ref->getDecl() == Variable && !Capturer)
Capturer = ref;
}
void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) {
if (Capturer) return;
Visit(ref->getBase());
if (Capturer && ref->isFreeIvar())
Capturer = ref;
}
void VisitBlockExpr(BlockExpr *block) {
// Look inside nested blocks
if (block->getBlockDecl()->capturesVariable(Variable))
Visit(block->getBlockDecl()->getBody());
}
void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) {
if (Capturer) return;
if (OVE->getSourceExpr())
Visit(OVE->getSourceExpr());
}
void VisitBinaryOperator(BinaryOperator *BinOp) {
if (!Variable || VarWillBeReased || BinOp->getOpcode() != BO_Assign)
return;
Expr *LHS = BinOp->getLHS();
if (const DeclRefExpr *DRE = dyn_cast_or_null<DeclRefExpr>(LHS)) {
if (DRE->getDecl() != Variable)
return;
if (Expr *RHS = BinOp->getRHS()) {
RHS = RHS->IgnoreParenCasts();
llvm::APSInt Value;
VarWillBeReased =
(RHS && RHS->isIntegerConstantExpr(Value, Context) && Value == 0);
}
}
}
};
}
/// Check whether the given argument is a block which captures a
/// variable.
static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) {
assert(owner.Variable && owner.Loc.isValid());
e = e->IgnoreParenCasts();
// Look through [^{...} copy] and Block_copy(^{...}).
if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) {
Selector Cmd = ME->getSelector();
if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") {
e = ME->getInstanceReceiver();
if (!e)
return nullptr;
e = e->IgnoreParenCasts();
}
} else if (CallExpr *CE = dyn_cast<CallExpr>(e)) {
if (CE->getNumArgs() == 1) {
FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl());
if (Fn) {
const IdentifierInfo *FnI = Fn->getIdentifier();
if (FnI && FnI->isStr("_Block_copy")) {
e = CE->getArg(0)->IgnoreParenCasts();
}
}
}
}
BlockExpr *block = dyn_cast<BlockExpr>(e);
if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable))
return nullptr;
FindCaptureVisitor visitor(S.Context, owner.Variable);
visitor.Visit(block->getBlockDecl()->getBody());
return visitor.VarWillBeReased ? nullptr : visitor.Capturer;
}
static void diagnoseRetainCycle(Sema &S, Expr *capturer,
RetainCycleOwner &owner) {
assert(capturer);
assert(owner.Variable && owner.Loc.isValid());
S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle)
<< owner.Variable << capturer->getSourceRange();
S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner)
<< owner.Indirect << owner.Range;
}
/// Check for a keyword selector that starts with the word 'add' or
/// 'set'.
static bool isSetterLikeSelector(Selector sel) {
if (sel.isUnarySelector()) return false;
StringRef str = sel.getNameForSlot(0);
while (!str.empty() && str.front() == '_') str = str.substr(1);
if (str.startswith("set"))
str = str.substr(3);
else if (str.startswith("add")) {
// Specially whitelist 'addOperationWithBlock:'.
if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock"))
return false;
str = str.substr(3);
}
else
return false;
if (str.empty()) return true;
return !isLowercase(str.front());
}
/// Check a message send to see if it's likely to cause a retain cycle.
void Sema::checkRetainCycles(ObjCMessageExpr *msg) {
// Only check instance methods whose selector looks like a setter.
if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector()))
return;
// Try to find a variable that the receiver is strongly owned by.
RetainCycleOwner owner;
if (msg->getReceiverKind() == ObjCMessageExpr::Instance) {
if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner))
return;
} else {
assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance);
owner.Variable = getCurMethodDecl()->getSelfDecl();
owner.Loc = msg->getSuperLoc();
owner.Range = msg->getSuperLoc();
}
// Check whether the receiver is captured by any of the arguments.
for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i)
if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner))
return diagnoseRetainCycle(*this, capturer, owner);
}
/// Check a property assign to see if it's likely to cause a retain cycle.
void Sema::checkRetainCycles(Expr *receiver, Expr *argument) {
RetainCycleOwner owner;
if (!findRetainCycleOwner(*this, receiver, owner))
return;
if (Expr *capturer = findCapturingExpr(*this, argument, owner))
diagnoseRetainCycle(*this, capturer, owner);
}
void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) {
RetainCycleOwner Owner;
if (!considerVariable(Var, /*DeclRefExpr=*/nullptr, Owner))
return;
// Because we don't have an expression for the variable, we have to set the
// location explicitly here.
Owner.Loc = Var->getLocation();
Owner.Range = Var->getSourceRange();
if (Expr *Capturer = findCapturingExpr(*this, Init, Owner))
diagnoseRetainCycle(*this, Capturer, Owner);
}
static bool checkUnsafeAssignLiteral(Sema &S, SourceLocation Loc,
Expr *RHS, bool isProperty) {
// Check if RHS is an Objective-C object literal, which also can get
// immediately zapped in a weak reference. Note that we explicitly
// allow ObjCStringLiterals, since those are designed to never really die.
RHS = RHS->IgnoreParenImpCasts();
// This enum needs to match with the 'select' in
// warn_objc_arc_literal_assign (off-by-1).
Sema::ObjCLiteralKind Kind = S.CheckLiteralKind(RHS);
if (Kind == Sema::LK_String || Kind == Sema::LK_None)
return false;
S.Diag(Loc, diag::warn_arc_literal_assign)
<< (unsigned) Kind
<< (isProperty ? 0 : 1)
<< RHS->getSourceRange();
return true;
}
static bool checkUnsafeAssignObject(Sema &S, SourceLocation Loc,
Qualifiers::ObjCLifetime LT,
Expr *RHS, bool isProperty) {
// Strip off any implicit cast added to get to the one ARC-specific.
while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
if (cast->getCastKind() == CK_ARCConsumeObject) {
S.Diag(Loc, diag::warn_arc_retained_assign)
<< (LT == Qualifiers::OCL_ExplicitNone)
<< (isProperty ? 0 : 1)
<< RHS->getSourceRange();
return true;
}
RHS = cast->getSubExpr();
}
if (LT == Qualifiers::OCL_Weak &&
checkUnsafeAssignLiteral(S, Loc, RHS, isProperty))
return true;
return false;
}
bool Sema::checkUnsafeAssigns(SourceLocation Loc,
QualType LHS, Expr *RHS) {
Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime();
if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone)
return false;
if (checkUnsafeAssignObject(*this, Loc, LT, RHS, false))
return true;
return false;
}
void Sema::checkUnsafeExprAssigns(SourceLocation Loc,
Expr *LHS, Expr *RHS) {
QualType LHSType;
// PropertyRef on LHS type need be directly obtained from
// its declaration as it has a PseudoType.
ObjCPropertyRefExpr *PRE
= dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens());
if (PRE && !PRE->isImplicitProperty()) {
const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
if (PD)
LHSType = PD->getType();
}
if (LHSType.isNull())
LHSType = LHS->getType();
Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime();
if (LT == Qualifiers::OCL_Weak) {
if (!Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, Loc))
getCurFunction()->markSafeWeakUse(LHS);
}
if (checkUnsafeAssigns(Loc, LHSType, RHS))
return;
// FIXME. Check for other life times.
if (LT != Qualifiers::OCL_None)
return;
if (PRE) {
if (PRE->isImplicitProperty())
return;
const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
if (!PD)
return;
unsigned Attributes = PD->getPropertyAttributes();
if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) {
// when 'assign' attribute was not explicitly specified
// by user, ignore it and rely on property type itself
// for lifetime info.
unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten();
if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) &&
LHSType->isObjCRetainableType())
return;
while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
if (cast->getCastKind() == CK_ARCConsumeObject) {
Diag(Loc, diag::warn_arc_retained_property_assign)
<< RHS->getSourceRange();
return;
}
RHS = cast->getSubExpr();
}
}
else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) {
if (checkUnsafeAssignObject(*this, Loc, Qualifiers::OCL_Weak, RHS, true))
return;
}
}
}
//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===//
namespace {
bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr,
SourceLocation StmtLoc,
const NullStmt *Body) {
// Do not warn if the body is a macro that expands to nothing, e.g:
//
// #define CALL(x)
// if (condition)
// CALL(0);
//
if (Body->hasLeadingEmptyMacro())
return false;
// Get line numbers of statement and body.
bool StmtLineInvalid;
unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc,
&StmtLineInvalid);
if (StmtLineInvalid)
return false;
bool BodyLineInvalid;
unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(),
&BodyLineInvalid);
if (BodyLineInvalid)
return false;
// Warn if null statement and body are on the same line.
if (StmtLine != BodyLine)
return false;
return true;
}
} // Unnamed namespace
void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
const Stmt *Body,
unsigned DiagID) {
// Since this is a syntactic check, don't emit diagnostic for template
// instantiations, this just adds noise.
if (CurrentInstantiationScope)
return;
// The body should be a null statement.
const NullStmt *NBody = dyn_cast<NullStmt>(Body);
if (!NBody)
return;
// Do the usual checks.
if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
return;
Diag(NBody->getSemiLoc(), DiagID);
Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
}
void Sema::DiagnoseEmptyLoopBody(const Stmt *S,
const Stmt *PossibleBody) {
assert(!CurrentInstantiationScope); // Ensured by caller
SourceLocation StmtLoc;
const Stmt *Body;
unsigned DiagID;
if (const ForStmt *FS = dyn_cast<ForStmt>(S)) {
StmtLoc = FS->getRParenLoc();
Body = FS->getBody();
DiagID = diag::warn_empty_for_body;
} else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) {
StmtLoc = WS->getCond()->getSourceRange().getEnd();
Body = WS->getBody();
DiagID = diag::warn_empty_while_body;
} else
return; // Neither `for' nor `while'.
// The body should be a null statement.
const NullStmt *NBody = dyn_cast<NullStmt>(Body);
if (!NBody)
return;
// Skip expensive checks if diagnostic is disabled.
if (Diags.isIgnored(DiagID, NBody->getSemiLoc()))
return;
// Do the usual checks.
if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
return;
// `for(...);' and `while(...);' are popular idioms, so in order to keep
// noise level low, emit diagnostics only if for/while is followed by a
// CompoundStmt, e.g.:
// for (int i = 0; i < n; i++);
// {
// a(i);
// }
// or if for/while is followed by a statement with more indentation
// than for/while itself:
// for (int i = 0; i < n; i++);
// a(i);
bool ProbableTypo = isa<CompoundStmt>(PossibleBody);
if (!ProbableTypo) {
bool BodyColInvalid;
unsigned BodyCol = SourceMgr.getPresumedColumnNumber(
PossibleBody->getLocStart(),
&BodyColInvalid);
if (BodyColInvalid)
return;
bool StmtColInvalid;
unsigned StmtCol = SourceMgr.getPresumedColumnNumber(
S->getLocStart(),
&StmtColInvalid);
if (StmtColInvalid)
return;
if (BodyCol > StmtCol)
ProbableTypo = true;
}
if (ProbableTypo) {
Diag(NBody->getSemiLoc(), DiagID);
Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
}
}
//===--- Layout compatibility ----------------------------------------------//
namespace {
bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2);
/// \brief Check if two enumeration types are layout-compatible.
bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) {
// C++11 [dcl.enum] p8:
// Two enumeration types are layout-compatible if they have the same
// underlying type.
return ED1->isComplete() && ED2->isComplete() &&
C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType());
}
/// \brief Check if two fields are layout-compatible.
bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) {
if (!isLayoutCompatible(C, Field1->getType(), Field2->getType()))
return false;
if (Field1->isBitField() != Field2->isBitField())
return false;
if (Field1->isBitField()) {
// Make sure that the bit-fields are the same length.
unsigned Bits1 = Field1->getBitWidthValue(C);
unsigned Bits2 = Field2->getBitWidthValue(C);
if (Bits1 != Bits2)
return false;
}
return true;
}
/// \brief Check if two standard-layout structs are layout-compatible.
/// (C++11 [class.mem] p17)
bool isLayoutCompatibleStruct(ASTContext &C,
RecordDecl *RD1,
RecordDecl *RD2) {
// If both records are C++ classes, check that base classes match.
if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) {
// If one of records is a CXXRecordDecl we are in C++ mode,
// thus the other one is a CXXRecordDecl, too.
const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2);
// Check number of base classes.
if (D1CXX->getNumBases() != D2CXX->getNumBases())
return false;
// Check the base classes.
for (CXXRecordDecl::base_class_const_iterator
Base1 = D1CXX->bases_begin(),
BaseEnd1 = D1CXX->bases_end(),
Base2 = D2CXX->bases_begin();
Base1 != BaseEnd1;
++Base1, ++Base2) {
if (!isLayoutCompatible(C, Base1->getType(), Base2->getType()))
return false;
}
} else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) {
// If only RD2 is a C++ class, it should have zero base classes.
if (D2CXX->getNumBases() > 0)
return false;
}
// Check the fields.
RecordDecl::field_iterator Field2 = RD2->field_begin(),
Field2End = RD2->field_end(),
Field1 = RD1->field_begin(),
Field1End = RD1->field_end();
for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) {
if (!isLayoutCompatible(C, *Field1, *Field2))
return false;
}
if (Field1 != Field1End || Field2 != Field2End)
return false;
return true;
}
/// \brief Check if two standard-layout unions are layout-compatible.
/// (C++11 [class.mem] p18)
bool isLayoutCompatibleUnion(ASTContext &C,
RecordDecl *RD1,
RecordDecl *RD2) {
llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields;
for (auto *Field2 : RD2->fields())
UnmatchedFields.insert(Field2);
for (auto *Field1 : RD1->fields()) {
llvm::SmallPtrSet<FieldDecl *, 8>::iterator
I = UnmatchedFields.begin(),
E = UnmatchedFields.end();
for ( ; I != E; ++I) {
if (isLayoutCompatible(C, Field1, *I)) {
bool Result = UnmatchedFields.erase(*I);
(void) Result;
assert(Result);
break;
}
}
if (I == E)
return false;
}
return UnmatchedFields.empty();
}
bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) {
if (RD1->isUnion() != RD2->isUnion())
return false;
if (RD1->isUnion())
return isLayoutCompatibleUnion(C, RD1, RD2);
else
return isLayoutCompatibleStruct(C, RD1, RD2);
}
/// \brief Check if two types are layout-compatible in C++11 sense.
bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) {
if (T1.isNull() || T2.isNull())
return false;
// C++11 [basic.types] p11:
// If two types T1 and T2 are the same type, then T1 and T2 are
// layout-compatible types.
if (C.hasSameType(T1, T2))
return true;
T1 = T1.getCanonicalType().getUnqualifiedType();
T2 = T2.getCanonicalType().getUnqualifiedType();
const Type::TypeClass TC1 = T1->getTypeClass();
const Type::TypeClass TC2 = T2->getTypeClass();
if (TC1 != TC2)
return false;
if (TC1 == Type::Enum) {
return isLayoutCompatible(C,
cast<EnumType>(T1)->getDecl(),
cast<EnumType>(T2)->getDecl());
} else if (TC1 == Type::Record) {
if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType())
return false;
return isLayoutCompatible(C,
cast<RecordType>(T1)->getDecl(),
cast<RecordType>(T2)->getDecl());
}
return false;
}
}
//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----//
namespace {
/// \brief Given a type tag expression find the type tag itself.
///
/// \param TypeExpr Type tag expression, as it appears in user's code.
///
/// \param VD Declaration of an identifier that appears in a type tag.
///
/// \param MagicValue Type tag magic value.
bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx,
const ValueDecl **VD, uint64_t *MagicValue) {
while(true) {
if (!TypeExpr)
return false;
TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts();
switch (TypeExpr->getStmtClass()) {
case Stmt::UnaryOperatorClass: {
const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr);
if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) {
TypeExpr = UO->getSubExpr();
continue;
}
return false;
}
case Stmt::DeclRefExprClass: {
const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr);
*VD = DRE->getDecl();
return true;
}
case Stmt::IntegerLiteralClass: {
const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr);
llvm::APInt MagicValueAPInt = IL->getValue();
if (MagicValueAPInt.getActiveBits() <= 64) {
*MagicValue = MagicValueAPInt.getZExtValue();
return true;
} else
return false;
}
case Stmt::BinaryConditionalOperatorClass:
case Stmt::ConditionalOperatorClass: {
const AbstractConditionalOperator *ACO =
cast<AbstractConditionalOperator>(TypeExpr);
bool Result;
if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) {
if (Result)
TypeExpr = ACO->getTrueExpr();
else
TypeExpr = ACO->getFalseExpr();
continue;
}
return false;
}
case Stmt::BinaryOperatorClass: {
const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr);
if (BO->getOpcode() == BO_Comma) {
TypeExpr = BO->getRHS();
continue;
}
return false;
}
default:
return false;
}
}
}
/// \brief Retrieve the C type corresponding to type tag TypeExpr.
///
/// \param TypeExpr Expression that specifies a type tag.
///
/// \param MagicValues Registered magic values.
///
/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong
/// kind.
///
/// \param TypeInfo Information about the corresponding C type.
///
/// \returns true if the corresponding C type was found.
bool GetMatchingCType(
const IdentifierInfo *ArgumentKind,
const Expr *TypeExpr, const ASTContext &Ctx,
const llvm::DenseMap<Sema::TypeTagMagicValue,
Sema::TypeTagData> *MagicValues,
bool &FoundWrongKind,
Sema::TypeTagData &TypeInfo) {
FoundWrongKind = false;
// Variable declaration that has type_tag_for_datatype attribute.
const ValueDecl *VD = nullptr;
uint64_t MagicValue;
if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue))
return false;
if (VD) {
if (TypeTagForDatatypeAttr *I = VD->getAttr<TypeTagForDatatypeAttr>()) {
if (I->getArgumentKind() != ArgumentKind) {
FoundWrongKind = true;
return false;
}
TypeInfo.Type = I->getMatchingCType();
TypeInfo.LayoutCompatible = I->getLayoutCompatible();
TypeInfo.MustBeNull = I->getMustBeNull();
return true;
}
return false;
}
if (!MagicValues)
return false;
llvm::DenseMap<Sema::TypeTagMagicValue,
Sema::TypeTagData>::const_iterator I =
MagicValues->find(std::make_pair(ArgumentKind, MagicValue));
if (I == MagicValues->end())
return false;
TypeInfo = I->second;
return true;
}
} // unnamed namespace
void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
uint64_t MagicValue, QualType Type,
bool LayoutCompatible,
bool MustBeNull) {
if (!TypeTagForDatatypeMagicValues)
TypeTagForDatatypeMagicValues.reset(
new llvm::DenseMap<TypeTagMagicValue, TypeTagData>);
TypeTagMagicValue Magic(ArgumentKind, MagicValue);
(*TypeTagForDatatypeMagicValues)[Magic] =
TypeTagData(Type, LayoutCompatible, MustBeNull);
}
namespace {
bool IsSameCharType(QualType T1, QualType T2) {
const BuiltinType *BT1 = T1->getAs<BuiltinType>();
if (!BT1)
return false;
const BuiltinType *BT2 = T2->getAs<BuiltinType>();
if (!BT2)
return false;
BuiltinType::Kind T1Kind = BT1->getKind();
BuiltinType::Kind T2Kind = BT2->getKind();
return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) ||
(T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) ||
(T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) ||
(T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar);
}
} // unnamed namespace
void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
const Expr * const *ExprArgs) {
const IdentifierInfo *ArgumentKind = Attr->getArgumentKind();
bool IsPointerAttr = Attr->getIsPointer();
const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()];
bool FoundWrongKind;
TypeTagData TypeInfo;
if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context,
TypeTagForDatatypeMagicValues.get(),
FoundWrongKind, TypeInfo)) {
if (FoundWrongKind)
Diag(TypeTagExpr->getExprLoc(),
diag::warn_type_tag_for_datatype_wrong_kind)
<< TypeTagExpr->getSourceRange();
return;
}
const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()];
if (IsPointerAttr) {
// Skip implicit cast of pointer to `void *' (as a function argument).
if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr))
if (ICE->getType()->isVoidPointerType() &&
ICE->getCastKind() == CK_BitCast)
ArgumentExpr = ICE->getSubExpr();
}
QualType ArgumentType = ArgumentExpr->getType();
// Passing a `void*' pointer shouldn't trigger a warning.
if (IsPointerAttr && ArgumentType->isVoidPointerType())
return;
if (TypeInfo.MustBeNull) {
// Type tag with matching void type requires a null pointer.
if (!ArgumentExpr->isNullPointerConstant(Context,
Expr::NPC_ValueDependentIsNotNull)) {
Diag(ArgumentExpr->getExprLoc(),
diag::warn_type_safety_null_pointer_required)
<< ArgumentKind->getName()
<< ArgumentExpr->getSourceRange()
<< TypeTagExpr->getSourceRange();
}
return;
}
QualType RequiredType = TypeInfo.Type;
if (IsPointerAttr)
RequiredType = Context.getPointerType(RequiredType);
bool mismatch = false;
if (!TypeInfo.LayoutCompatible) {
mismatch = !Context.hasSameType(ArgumentType, RequiredType);
// C++11 [basic.fundamental] p1:
// Plain char, signed char, and unsigned char are three distinct types.
//
// But we treat plain `char' as equivalent to `signed char' or `unsigned
// char' depending on the current char signedness mode.
if (mismatch)
if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(),
RequiredType->getPointeeType())) ||
(!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType)))
mismatch = false;
} else
if (IsPointerAttr)
mismatch = !isLayoutCompatible(Context,
ArgumentType->getPointeeType(),
RequiredType->getPointeeType());
else
mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType);
if (mismatch)
Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch)
<< ArgumentType << ArgumentKind
<< TypeInfo.LayoutCompatible << RequiredType
<< ArgumentExpr->getSourceRange()
<< TypeTagExpr->getSourceRange();
}