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//===--- Sema.cpp - AST Builder and Semantic Analysis Implementation ------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the actions class which performs semantic analysis and
// builds an AST out of a parse stream.
//
//===----------------------------------------------------------------------===//
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/DelayedDiagnostic.h"
#include "TargetAttributesSema.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/APFloat.h"
#include "clang/Sema/CXXFieldCollector.h"
#include "clang/Sema/ExternalSemaSource.h"
#include "clang/Sema/PrettyDeclStackTrace.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTDiagnostic.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Expr.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/TargetInfo.h"
using namespace clang;
using namespace sema;
FunctionScopeInfo::~FunctionScopeInfo() { }
void FunctionScopeInfo::Clear(unsigned NumErrors) {
HasBranchProtectedScope = false;
HasBranchIntoScope = false;
HasIndirectGoto = false;
LabelMap.clear();
SwitchStack.clear();
Returns.clear();
NumErrorsAtStartOfFunction = NumErrors;
}
BlockScopeInfo::~BlockScopeInfo() { }
void Sema::ActOnTranslationUnitScope(Scope *S) {
TUScope = S;
PushDeclContext(S, Context.getTranslationUnitDecl());
VAListTagName = PP.getIdentifierInfo("__va_list_tag");
if (!Context.isInt128Installed() && // May be set by ASTReader.
PP.getTargetInfo().getPointerWidth(0) >= 64) {
TypeSourceInfo *TInfo;
// Install [u]int128_t for 64-bit targets.
TInfo = Context.getTrivialTypeSourceInfo(Context.Int128Ty);
PushOnScopeChains(TypedefDecl::Create(Context, CurContext,
SourceLocation(),
&Context.Idents.get("__int128_t"),
TInfo), TUScope);
TInfo = Context.getTrivialTypeSourceInfo(Context.UnsignedInt128Ty);
PushOnScopeChains(TypedefDecl::Create(Context, CurContext,
SourceLocation(),
&Context.Idents.get("__uint128_t"),
TInfo), TUScope);
Context.setInt128Installed();
}
if (!PP.getLangOptions().ObjC1) return;
// Built-in ObjC types may already be set by ASTReader (hence isNull checks).
if (Context.getObjCSelType().isNull()) {
// Create the built-in typedef for 'SEL'.
QualType SelT = Context.getPointerType(Context.ObjCBuiltinSelTy);
TypeSourceInfo *SelInfo = Context.getTrivialTypeSourceInfo(SelT);
TypedefDecl *SelTypedef
= TypedefDecl::Create(Context, CurContext, SourceLocation(),
&Context.Idents.get("SEL"), SelInfo);
PushOnScopeChains(SelTypedef, TUScope);
Context.setObjCSelType(Context.getTypeDeclType(SelTypedef));
Context.ObjCSelRedefinitionType = Context.getObjCSelType();
}
// Synthesize "@class Protocol;
if (Context.getObjCProtoType().isNull()) {
ObjCInterfaceDecl *ProtocolDecl =
ObjCInterfaceDecl::Create(Context, CurContext, SourceLocation(),
&Context.Idents.get("Protocol"),
SourceLocation(), true);
Context.setObjCProtoType(Context.getObjCInterfaceType(ProtocolDecl));
PushOnScopeChains(ProtocolDecl, TUScope, false);
}
// Create the built-in typedef for 'id'.
if (Context.getObjCIdType().isNull()) {
QualType T = Context.getObjCObjectType(Context.ObjCBuiltinIdTy, 0, 0);
T = Context.getObjCObjectPointerType(T);
TypeSourceInfo *IdInfo = Context.getTrivialTypeSourceInfo(T);
TypedefDecl *IdTypedef
= TypedefDecl::Create(Context, CurContext, SourceLocation(),
&Context.Idents.get("id"), IdInfo);
PushOnScopeChains(IdTypedef, TUScope);
Context.setObjCIdType(Context.getTypeDeclType(IdTypedef));
Context.ObjCIdRedefinitionType = Context.getObjCIdType();
}
// Create the built-in typedef for 'Class'.
if (Context.getObjCClassType().isNull()) {
QualType T = Context.getObjCObjectType(Context.ObjCBuiltinClassTy, 0, 0);
T = Context.getObjCObjectPointerType(T);
TypeSourceInfo *ClassInfo = Context.getTrivialTypeSourceInfo(T);
TypedefDecl *ClassTypedef
= TypedefDecl::Create(Context, CurContext, SourceLocation(),
&Context.Idents.get("Class"), ClassInfo);
PushOnScopeChains(ClassTypedef, TUScope);
Context.setObjCClassType(Context.getTypeDeclType(ClassTypedef));
Context.ObjCClassRedefinitionType = Context.getObjCClassType();
}
}
Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
bool CompleteTranslationUnit,
CodeCompleteConsumer *CodeCompleter)
: TheTargetAttributesSema(0),
LangOpts(pp.getLangOptions()), PP(pp), Context(ctxt), Consumer(consumer),
Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()),
ExternalSource(0), CodeCompleter(CodeCompleter), CurContext(0),
PackContext(0), VisContext(0), ParsingDeclDepth(0),
IdResolver(pp.getLangOptions()), CXXTypeInfoDecl(0), MSVCGuidDecl(0),
GlobalNewDeleteDeclared(false),
CompleteTranslationUnit(CompleteTranslationUnit),
NumSFINAEErrors(0), SuppressAccessChecking(false),
NonInstantiationEntries(0), CurrentInstantiationScope(0), TyposCorrected(0),
AnalysisWarnings(*this)
{
TUScope = 0;
if (getLangOptions().CPlusPlus)
FieldCollector.reset(new CXXFieldCollector());
// Tell diagnostics how to render things from the AST library.
PP.getDiagnostics().SetArgToStringFn(&FormatASTNodeDiagnosticArgument,
&Context);
ExprEvalContexts.push_back(
ExpressionEvaluationContextRecord(PotentiallyEvaluated, 0));
FunctionScopes.push_back(new FunctionScopeInfo(Diags.getNumErrors()));
}
void Sema::Initialize() {
// Tell the AST consumer about this Sema object.
Consumer.Initialize(Context);
// FIXME: Isn't this redundant with the initialization above?
if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
SC->InitializeSema(*this);
// Tell the external Sema source about this Sema object.
if (ExternalSemaSource *ExternalSema
= dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
ExternalSema->InitializeSema(*this);
}
Sema::~Sema() {
if (PackContext) FreePackedContext();
if (VisContext) FreeVisContext();
delete TheTargetAttributesSema;
// Kill all the active scopes.
for (unsigned I = 1, E = FunctionScopes.size(); I != E; ++I)
delete FunctionScopes[I];
if (FunctionScopes.size() == 1)
delete FunctionScopes[0];
// Tell the SemaConsumer to forget about us; we're going out of scope.
if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
SC->ForgetSema();
// Detach from the external Sema source.
if (ExternalSemaSource *ExternalSema
= dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
ExternalSema->ForgetSema();
}
/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
/// If there is already an implicit cast, merge into the existing one.
/// The result is of the given category.
void Sema::ImpCastExprToType(Expr *&Expr, QualType Ty,
CastKind Kind, ExprValueKind VK,
const CXXCastPath *BasePath) {
QualType ExprTy = Context.getCanonicalType(Expr->getType());
QualType TypeTy = Context.getCanonicalType(Ty);
if (ExprTy == TypeTy)
return;
if (Expr->getType()->isPointerType() && Ty->isPointerType()) {
QualType ExprBaseType = cast<PointerType>(ExprTy)->getPointeeType();
QualType BaseType = cast<PointerType>(TypeTy)->getPointeeType();
if (ExprBaseType.getAddressSpace() != BaseType.getAddressSpace()) {
Diag(Expr->getExprLoc(), diag::err_implicit_pointer_address_space_cast)
<< Expr->getSourceRange();
}
}
// If this is a derived-to-base cast to a through a virtual base, we
// need a vtable.
if (Kind == CK_DerivedToBase &&
BasePathInvolvesVirtualBase(*BasePath)) {
QualType T = Expr->getType();
if (const PointerType *Pointer = T->getAs<PointerType>())
T = Pointer->getPointeeType();
if (const RecordType *RecordTy = T->getAs<RecordType>())
MarkVTableUsed(Expr->getLocStart(),
cast<CXXRecordDecl>(RecordTy->getDecl()));
}
if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(Expr)) {
if (ImpCast->getCastKind() == Kind && (!BasePath || BasePath->empty())) {
ImpCast->setType(Ty);
ImpCast->setValueKind(VK);
return;
}
}
Expr = ImplicitCastExpr::Create(Context, Ty, Kind, Expr, BasePath, VK);
}
ExprValueKind Sema::CastCategory(Expr *E) {
Expr::Classification Classification = E->Classify(Context);
return Classification.isRValue() ? VK_RValue :
(Classification.isLValue() ? VK_LValue : VK_XValue);
}
/// \brief Used to prune the decls of Sema's UnusedFileScopedDecls vector.
static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) {
if (D->isUsed())
return true;
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
// UnusedFileScopedDecls stores the first declaration.
// The declaration may have become definition so check again.
const FunctionDecl *DeclToCheck;
if (FD->hasBody(DeclToCheck))
return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
// Later redecls may add new information resulting in not having to warn,
// so check again.
DeclToCheck = FD->getMostRecentDeclaration();
if (DeclToCheck != FD)
return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
}
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
// UnusedFileScopedDecls stores the first declaration.
// The declaration may have become definition so check again.
const VarDecl *DeclToCheck = VD->getDefinition();
if (DeclToCheck)
return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
// Later redecls may add new information resulting in not having to warn,
// so check again.
DeclToCheck = VD->getMostRecentDeclaration();
if (DeclToCheck != VD)
return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
}
return false;
}
/// ActOnEndOfTranslationUnit - This is called at the very end of the
/// translation unit when EOF is reached and all but the top-level scope is
/// popped.
void Sema::ActOnEndOfTranslationUnit() {
// At PCH writing, implicit instantiations and VTable handling info are
// stored and performed when the PCH is included.
if (CompleteTranslationUnit)
while (1) {
// C++: Perform implicit template instantiations.
//
// FIXME: When we perform these implicit instantiations, we do not
// carefully keep track of the point of instantiation (C++ [temp.point]).
// This means that name lookup that occurs within the template
// instantiation will always happen at the end of the translation unit,
// so it will find some names that should not be found. Although this is
// common behavior for C++ compilers, it is technically wrong. In the
// future, we either need to be able to filter the results of name lookup
// or we need to perform template instantiations earlier.
PerformPendingInstantiations();
/// If DefinedUsedVTables ends up marking any virtual member
/// functions it might lead to more pending template
/// instantiations, which is why we need to loop here.
if (!DefineUsedVTables())
break;
}
// Remove file scoped decls that turned out to be used.
UnusedFileScopedDecls.erase(std::remove_if(UnusedFileScopedDecls.begin(),
UnusedFileScopedDecls.end(),
std::bind1st(std::ptr_fun(ShouldRemoveFromUnused),
this)),
UnusedFileScopedDecls.end());
if (!CompleteTranslationUnit) {
TUScope = 0;
return;
}
// Check for #pragma weak identifiers that were never declared
// FIXME: This will cause diagnostics to be emitted in a non-determinstic
// order! Iterating over a densemap like this is bad.
for (llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator
I = WeakUndeclaredIdentifiers.begin(),
E = WeakUndeclaredIdentifiers.end(); I != E; ++I) {
if (I->second.getUsed()) continue;
Diag(I->second.getLocation(), diag::warn_weak_identifier_undeclared)
<< I->first;
}
// C99 6.9.2p2:
// A declaration of an identifier for an object that has file
// scope without an initializer, and without a storage-class
// specifier or with the storage-class specifier static,
// constitutes a tentative definition. If a translation unit
// contains one or more tentative definitions for an identifier,
// and the translation unit contains no external definition for
// that identifier, then the behavior is exactly as if the
// translation unit contains a file scope declaration of that
// identifier, with the composite type as of the end of the
// translation unit, with an initializer equal to 0.
llvm::SmallSet<VarDecl *, 32> Seen;
for (unsigned i = 0, e = TentativeDefinitions.size(); i != e; ++i) {
VarDecl *VD = TentativeDefinitions[i]->getActingDefinition();
// If the tentative definition was completed, getActingDefinition() returns
// null. If we've already seen this variable before, insert()'s second
// return value is false.
if (VD == 0 || VD->isInvalidDecl() || !Seen.insert(VD))
continue;
if (const IncompleteArrayType *ArrayT
= Context.getAsIncompleteArrayType(VD->getType())) {
if (RequireCompleteType(VD->getLocation(),
ArrayT->getElementType(),
diag::err_tentative_def_incomplete_type_arr)) {
VD->setInvalidDecl();
continue;
}
// Set the length of the array to 1 (C99 6.9.2p5).
Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
QualType T = Context.getConstantArrayType(ArrayT->getElementType(),
One, ArrayType::Normal, 0);
VD->setType(T);
} else if (RequireCompleteType(VD->getLocation(), VD->getType(),
diag::err_tentative_def_incomplete_type))
VD->setInvalidDecl();
// Notify the consumer that we've completed a tentative definition.
if (!VD->isInvalidDecl())
Consumer.CompleteTentativeDefinition(VD);
}
// Output warning for unused file scoped decls.
for (llvm::SmallVectorImpl<const DeclaratorDecl*>::iterator
I = UnusedFileScopedDecls.begin(),
E = UnusedFileScopedDecls.end(); I != E; ++I) {
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
const FunctionDecl *DiagD;
if (!FD->hasBody(DiagD))
DiagD = FD;
Diag(DiagD->getLocation(),
isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function
: diag::warn_unused_function)
<< DiagD->getDeclName();
} else {
const VarDecl *DiagD = cast<VarDecl>(*I)->getDefinition();
if (!DiagD)
DiagD = cast<VarDecl>(*I);
Diag(DiagD->getLocation(), diag::warn_unused_variable)
<< DiagD->getDeclName();
}
}
TUScope = 0;
}
//===----------------------------------------------------------------------===//
// Helper functions.
//===----------------------------------------------------------------------===//
DeclContext *Sema::getFunctionLevelDeclContext() {
DeclContext *DC = CurContext;
while (isa<BlockDecl>(DC) || isa<EnumDecl>(DC))
DC = DC->getParent();
return DC;
}
/// getCurFunctionDecl - If inside of a function body, this returns a pointer
/// to the function decl for the function being parsed. If we're currently
/// in a 'block', this returns the containing context.
FunctionDecl *Sema::getCurFunctionDecl() {
DeclContext *DC = getFunctionLevelDeclContext();
return dyn_cast<FunctionDecl>(DC);
}
ObjCMethodDecl *Sema::getCurMethodDecl() {
DeclContext *DC = getFunctionLevelDeclContext();
return dyn_cast<ObjCMethodDecl>(DC);
}
NamedDecl *Sema::getCurFunctionOrMethodDecl() {
DeclContext *DC = getFunctionLevelDeclContext();
if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
return cast<NamedDecl>(DC);
return 0;
}
Sema::SemaDiagnosticBuilder::~SemaDiagnosticBuilder() {
if (!this->Emit())
return;
// If this is not a note, and we're in a template instantiation
// that is different from the last template instantiation where
// we emitted an error, print a template instantiation
// backtrace.
if (!SemaRef.Diags.isBuiltinNote(DiagID) &&
!SemaRef.ActiveTemplateInstantiations.empty() &&
SemaRef.ActiveTemplateInstantiations.back()
!= SemaRef.LastTemplateInstantiationErrorContext) {
SemaRef.PrintInstantiationStack();
SemaRef.LastTemplateInstantiationErrorContext
= SemaRef.ActiveTemplateInstantiations.back();
}
}
Sema::SemaDiagnosticBuilder Sema::Diag(SourceLocation Loc, unsigned DiagID) {
if (isSFINAEContext()) {
switch (Diagnostic::getDiagnosticSFINAEResponse(DiagID)) {
case Diagnostic::SFINAE_Report:
// Fall through; we'll report the diagnostic below.
break;
case Diagnostic::SFINAE_SubstitutionFailure:
// Count this failure so that we know that template argument deduction
// has failed.
++NumSFINAEErrors;
// Fall through
case Diagnostic::SFINAE_Suppress:
// Suppress this diagnostic.
Diags.setLastDiagnosticIgnored();
return SemaDiagnosticBuilder(*this);
}
}
DiagnosticBuilder DB = Diags.Report(FullSourceLoc(Loc, SourceMgr), DiagID);
return SemaDiagnosticBuilder(DB, *this, DiagID);
}
Sema::SemaDiagnosticBuilder
Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) {
SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID()));
PD.Emit(Builder);
return Builder;
}
/// \brief Determines the active Scope associated with the given declaration
/// context.
///
/// This routine maps a declaration context to the active Scope object that
/// represents that declaration context in the parser. It is typically used
/// from "scope-less" code (e.g., template instantiation, lazy creation of
/// declarations) that injects a name for name-lookup purposes and, therefore,
/// must update the Scope.
///
/// \returns The scope corresponding to the given declaraion context, or NULL
/// if no such scope is open.
Scope *Sema::getScopeForContext(DeclContext *Ctx) {
if (!Ctx)
return 0;
Ctx = Ctx->getPrimaryContext();
for (Scope *S = getCurScope(); S; S = S->getParent()) {
// Ignore scopes that cannot have declarations. This is important for
// out-of-line definitions of static class members.
if (S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope))
if (DeclContext *Entity = static_cast<DeclContext *> (S->getEntity()))
if (Ctx == Entity->getPrimaryContext())
return S;
}
return 0;
}
/// \brief Enter a new function scope
void Sema::PushFunctionScope() {
if (FunctionScopes.size() == 1) {
// Use the "top" function scope rather than having to allocate
// memory for a new scope.
FunctionScopes.back()->Clear(getDiagnostics().getNumErrors());
FunctionScopes.push_back(FunctionScopes.back());
return;
}
FunctionScopes.push_back(
new FunctionScopeInfo(getDiagnostics().getNumErrors()));
}
void Sema::PushBlockScope(Scope *BlockScope, BlockDecl *Block) {
FunctionScopes.push_back(new BlockScopeInfo(getDiagnostics().getNumErrors(),
BlockScope, Block));
}
void Sema::PopFunctionOrBlockScope() {
FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
assert(!FunctionScopes.empty() && "mismatched push/pop!");
if (FunctionScopes.back() != Scope)
delete Scope;
}
/// \brief Determine whether any errors occurred within this function/method/
/// block.
bool Sema::hasAnyErrorsInThisFunction() const {
return getCurFunction()->NumErrorsAtStartOfFunction
!= getDiagnostics().getNumErrors();
}
BlockScopeInfo *Sema::getCurBlock() {
if (FunctionScopes.empty())
return 0;
return dyn_cast<BlockScopeInfo>(FunctionScopes.back());
}
// Pin this vtable to this file.
ExternalSemaSource::~ExternalSemaSource() {}
void PrettyDeclStackTraceEntry::print(llvm::raw_ostream &OS) const {
SourceLocation Loc = this->Loc;
if (!Loc.isValid() && TheDecl) Loc = TheDecl->getLocation();
if (Loc.isValid()) {
Loc.print(OS, S.getSourceManager());
OS << ": ";
}
OS << Message;
if (TheDecl && isa<NamedDecl>(TheDecl)) {
std::string Name = cast<NamedDecl>(TheDecl)->getNameAsString();
if (!Name.empty())
OS << " '" << Name << '\'';
}
OS << '\n';
}