Implement runtime checks for undefined behavior. WIP.
This implements a new flag -fcatch-undefined-behavior. The flag turns
on additional runtime checks for:
T a[I];
a[i] abort when i < 0 or i >= I.
Future stuff includes shifts by >= bitwidth amounts.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@91198 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 70fa004..722ec86 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1012,6 +1012,36 @@
}
}
+static llvm::Constant *getAbortFn(CodeGenFunction &CGF) {
+ // void abort();
+
+ const llvm::FunctionType *FTy =
+ llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), false);
+
+ return CGF.CGM.CreateRuntimeFunction(FTy, "abort");
+}
+
+llvm::BasicBlock*CodeGenFunction::getAbortBB() {
+ if (AbortBB)
+ return AbortBB;
+
+ llvm::BasicBlock *Cont = 0;
+ if (HaveInsertPoint()) {
+ Cont = createBasicBlock("cont");
+ EmitBranch(Cont);
+ }
+ AbortBB = createBasicBlock("abort");
+ EmitBlock(AbortBB);
+ llvm::CallInst *AbortCall = Builder.CreateCall(getAbortFn(*this));
+ AbortCall->setDoesNotReturn();
+ AbortCall->setDoesNotThrow();
+ Builder.CreateUnreachable();
+
+ if (Cont)
+ EmitBlock(Cont);
+ return AbortBB;
+}
+
LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
// The index must always be an integer, which is not an aggregate. Emit it.
llvm::Value *Idx = EmitScalarExpr(E->getIdx());
@@ -1040,6 +1070,37 @@
llvm::IntegerType::get(VMContext, LLVMPointerWidth),
IdxSigned, "idxprom");
+ if (CatchUndefined) {
+ if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E->getBase())) {
+ if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
+ if (ICE->getCastKind() == CastExpr::CK_ArrayToPointerDecay) {
+ if (const ConstantArrayType *CAT
+ = getContext().getAsConstantArrayType(DRE->getType())) {
+ llvm::APInt Size = CAT->getSize();
+ llvm::BasicBlock *Cont = createBasicBlock("cont");
+ if (IdxSigned) {
+ Builder.CreateCondBr(Builder.CreateICmpSGE(Idx,
+ llvm::ConstantInt::get(Idx->getType(), 0)),
+ Cont, getAbortBB());
+ EmitBlock(Cont);
+ Cont = createBasicBlock("cont");
+ Builder.CreateCondBr(Builder.CreateICmpSLT(Idx,
+ llvm::ConstantInt::get(Idx->getType(), Size)),
+ Cont, getAbortBB());
+ EmitBlock(Cont);
+ } else {
+ llvm::BasicBlock *Cont = createBasicBlock("cont");
+ Builder.CreateCondBr(Builder.CreateICmpULT(Idx,
+ llvm::ConstantInt::get(Idx->getType(), Size)),
+ Cont, getAbortBB());
+ EmitBlock(Cont);
+ }
+ }
+ }
+ }
+ }
+ }
+
// We know that the pointer points to a type of the correct size, unless the
// size is a VLA or Objective-C interface.
llvm::Value *Address = 0;
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 2696452..db604f6 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -32,10 +32,11 @@
SwitchInsn(0), CaseRangeBlock(0), InvokeDest(0),
CXXThisDecl(0), CXXVTTDecl(0),
ConditionalBranchLevel(0), TerminateHandler(0),
- UniqueAggrDestructorCount(0) {
+ UniqueAggrDestructorCount(0), AbortBB(0) {
LLVMIntTy = ConvertType(getContext().IntTy);
LLVMPointerWidth = Target.getPointerWidth(0);
Exceptions = getContext().getLangOptions().Exceptions;
+ CatchUndefined = getContext().getLangOptions().CatchUndefined;
}
ASTContext &CodeGenFunction::getContext() const {
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 1ddfa6d..8820e6e 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -108,6 +108,7 @@
uint32_t LLVMPointerWidth;
bool Exceptions;
+ bool CatchUndefined;
public:
/// ObjCEHValueStack - Stack of Objective-C exception values, used for
/// rethrows.
@@ -1266,6 +1267,11 @@
ArgType));
}
}
+
+ llvm::BasicBlock *AbortBB;
+ /// getAbortBB - Create a basic block that will call abort. We'll generate
+ /// a branch around the created basic block as necessary.
+ llvm::BasicBlock* getAbortBB();
};
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 1d82d82..4279db5 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -895,6 +895,7 @@
}
// Forward -f (flag) options which we can pass directly.
+ Args.AddLastArg(CmdArgs, options::OPT_fcatch_undefined_behavior);
Args.AddLastArg(CmdArgs, options::OPT_femit_all_decls);
Args.AddLastArg(CmdArgs, options::OPT_ffreestanding);
Args.AddLastArg(CmdArgs, options::OPT_fheinous_gnu_extensions);
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 1f64e1e..3b9d5d0 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -447,6 +447,8 @@
Res.push_back("-fno-operator-names");
if (Opts.PascalStrings)
Res.push_back("-fpascal-strings");
+ if (Opts.CatchUndefined)
+ Res.push_back("-fcatch-undefined-behavior");
if (Opts.WritableStrings)
Res.push_back("-fwritable-strings");
if (!Opts.LaxVectorConversions)
@@ -1151,6 +1153,7 @@
Opts.ObjCConstantStringClass = getLastArgValue(Args,
OPT_fconstant_string_class);
Opts.ObjCNonFragileABI = Args.hasArg(OPT_fobjc_nonfragile_abi);
+ Opts.CatchUndefined = Args.hasArg(OPT_fcatch_undefined_behavior);
Opts.EmitAllDecls = Args.hasArg(OPT_femit_all_decls);
Opts.PICLevel = getLastArgIntValue(Args, OPT_pic_level, 0, Diags);
Opts.Static = Args.hasArg(OPT_static_define);
diff --git a/lib/Frontend/PCHReader.cpp b/lib/Frontend/PCHReader.cpp
index aae2014..58209c8 100644
--- a/lib/Frontend/PCHReader.cpp
+++ b/lib/Frontend/PCHReader.cpp
@@ -116,6 +116,7 @@
diag::warn_pch_stack_protector);
PARSE_LANGOPT_BENIGN(InstantiationDepth);
PARSE_LANGOPT_IMPORTANT(OpenCL, diag::warn_pch_opencl);
+ PARSE_LANGOPT_BENIGN(CatchUndefined);
PARSE_LANGOPT_IMPORTANT(ElideConstructors, diag::warn_pch_elide_constructors);
#undef PARSE_LANGOPT_IRRELEVANT
#undef PARSE_LANGOPT_BENIGN
@@ -1719,6 +1720,8 @@
++Idx;
PARSE_LANGOPT(InstantiationDepth);
PARSE_LANGOPT(OpenCL);
+ PARSE_LANGOPT(CatchUndefined);
+ // FIXME: Missing ElideConstructors?!
#undef PARSE_LANGOPT
return Listener->ReadLanguageOptions(LangOpts);
diff --git a/lib/Frontend/PCHWriter.cpp b/lib/Frontend/PCHWriter.cpp
index a190013..681c1ff 100644
--- a/lib/Frontend/PCHWriter.cpp
+++ b/lib/Frontend/PCHWriter.cpp
@@ -781,6 +781,7 @@
Record.push_back(LangOpts.getStackProtectorMode());
Record.push_back(LangOpts.InstantiationDepth);
Record.push_back(LangOpts.OpenCL);
+ Record.push_back(LangOpts.CatchUndefined);
Record.push_back(LangOpts.ElideConstructors);
Stream.EmitRecord(pch::LANGUAGE_OPTIONS, Record);
}