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[asan] insert crash basic blocks inline as opposed to inserting them at the end of the function. This doesn't seem to fix or break anything, but is considered to be more friendly to downstream passes 

llvm-svn: 161870
This commit is contained in:
Kostya Serebryany 2012-08-14 14:04:51 +00:00
parent eb39adc9fa
commit fda7a138f7
1 changed files with 27 additions and 30 deletions
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55
llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
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@ -159,7 +159,7 @@ struct AddressSanitizer : public ModulePass {
Value *Addr, uint32_t TypeSize, bool IsWrite);
Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
Value *ShadowValue, uint32_t TypeSize);
Instruction *generateCrashCode(BasicBlock *BB, Value *Addr, Value *PC,
Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
bool IsWrite, size_t AccessSizeIndex);
bool instrumentMemIntrinsic(AsanFunctionContext &AFC, MemIntrinsic *MI);
void instrumentMemIntrinsicParam(AsanFunctionContext &AFC,
@ -251,24 +251,24 @@ static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
// ThenBlock
// Tail
//
// If ThenBlock is zero, a new block is created and its terminator is returned.
// Otherwize 0 is returned.
static BranchInst *splitBlockAndInsertIfThen(Value *Cmp,
BasicBlock *ThenBlock = 0) {
// ThenBlock block is created and its terminator is returned.
// If Unreachable, ThenBlock is terminated with UnreachableInst, otherwise
// it is terminated with BranchInst to Tail.
static TerminatorInst *splitBlockAndInsertIfThen(Value *Cmp, bool Unreachable) {
Instruction *SplitBefore = cast<Instruction>(Cmp)->getNextNode();
BasicBlock *Head = SplitBefore->getParent();
BasicBlock *Tail = Head->splitBasicBlock(SplitBefore);
TerminatorInst *HeadOldTerm = Head->getTerminator();
BranchInst *CheckTerm = 0;
if (!ThenBlock) {
LLVMContext &C = Head->getParent()->getParent()->getContext();
ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
BasicBlock *ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
TerminatorInst *CheckTerm;
if (Unreachable)
CheckTerm = new UnreachableInst(C, ThenBlock);
else
CheckTerm = BranchInst::Create(Tail, ThenBlock);
}
BranchInst *HeadNewTerm =
BranchInst::Create(/*ifTrue*/ThenBlock, /*ifFalse*/Tail, Cmp);
ReplaceInstWithInst(HeadOldTerm, HeadNewTerm);
return CheckTerm;
}
@ -320,7 +320,7 @@ bool AddressSanitizer::instrumentMemIntrinsic(AsanFunctionContext &AFC,
Value *Cmp = IRB.CreateICmpNE(Length,
Constant::getNullValue(Length->getType()));
InsertBefore = splitBlockAndInsertIfThen(Cmp);
InsertBefore = splitBlockAndInsertIfThen(Cmp, false);
}
instrumentMemIntrinsicParam(AFC, MI, Dst, Length, InsertBefore, true);
@ -391,15 +391,11 @@ Function *AddressSanitizer::checkInterfaceFunction(Constant *FuncOrBitcast) {
}
Instruction *AddressSanitizer::generateCrashCode(
BasicBlock *BB, Value *Addr, Value *PC,
Instruction *InsertBefore, Value *Addr,
bool IsWrite, size_t AccessSizeIndex) {
IRBuilder<> IRB(BB->getFirstNonPHI());
CallInst *Call;
if (PC)
Call = IRB.CreateCall2(AsanErrorCallback[IsWrite][AccessSizeIndex],
Addr, PC);
else
Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex], Addr);
IRBuilder<> IRB(InsertBefore);
CallInst *Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex],
Addr);
// We don't do Call->setDoesNotReturn() because the BB already has
// UnreachableInst at the end.
// This EmptyAsm is required to avoid callback merge.
@ -440,26 +436,27 @@ void AddressSanitizer::instrumentAddress(AsanFunctionContext &AFC,
IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
BasicBlock *CrashBlock = BasicBlock::Create(*C, "crash_bb", &AFC.F);
new UnreachableInst(*C, CrashBlock);
size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
Instruction *Crash =
generateCrashCode(CrashBlock, AddrLong, 0, IsWrite, AccessSizeIndex);
Crash->setDebugLoc(OrigIns->getDebugLoc());
size_t Granularity = 1 << MappingScale;
TerminatorInst *CrashTerm = 0;
if (TypeSize < 8 * Granularity) {
BranchInst *CheckTerm = splitBlockAndInsertIfThen(Cmp);
assert(CheckTerm->isUnconditional());
TerminatorInst *CheckTerm = splitBlockAndInsertIfThen(Cmp, false);
assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
BasicBlock *NextBB = CheckTerm->getSuccessor(0);
IRB.SetInsertPoint(CheckTerm);
Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
BasicBlock *CrashBlock = BasicBlock::Create(*C, "", &AFC.F, NextBB);
CrashTerm = new UnreachableInst(*C, CrashBlock);
BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
ReplaceInstWithInst(CheckTerm, NewTerm);
} else {
splitBlockAndInsertIfThen(Cmp, CrashBlock);
CrashTerm = splitBlockAndInsertIfThen(Cmp, true);
}
Instruction *Crash =
generateCrashCode(CrashTerm, AddrLong, IsWrite, AccessSizeIndex);
Crash->setDebugLoc(OrigIns->getDebugLoc());
}
// This function replaces all global variables with new variables that have