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-rw-r--r--lib/Transforms/Instrumentation/AddressSanitizer.cpp64
1 files changed, 32 insertions, 32 deletions
diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index bf35eac..17b83ce 100644
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -86,6 +86,9 @@ static cl::opt<bool> ClInstrumentWrites("asan-instrument-writes",
static cl::opt<bool> ClInstrumentAtomics("asan-instrument-atomics",
cl::desc("instrument atomic instructions (rmw, cmpxchg)"),
cl::Hidden, cl::init(true));
+static cl::opt<bool> ClAlwaysSlowPath("asan-always-slow-path",
+ cl::desc("use instrumentation with slow path for all accesses"),
+ cl::Hidden, cl::init(false));
// This flag limits the number of instructions to be instrumented
// in any given BB. Normally, this should be set to unlimited (INT_MAX),
// but due to http://llvm.org/bugs/show_bug.cgi?id=12652 we temporary
@@ -159,7 +162,7 @@ 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 +254,24 @@ 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);
+ LLVMContext &C = Head->getParent()->getParent()->getContext();
+ 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 +323,7 @@ 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 +394,11 @@ 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.
@@ -420,7 +419,7 @@ Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
// (uint8_t) ((Addr & (Granularity-1)) + size - 1)
LastAccessedByte = IRB.CreateIntCast(
- LastAccessedByte, IRB.getInt8Ty(), false);
+ LastAccessedByte, ShadowValue->getType(), false);
// ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
}
@@ -440,26 +439,27 @@ 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;
- if (TypeSize < 8 * Granularity) {
- BranchInst *CheckTerm = splitBlockAndInsertIfThen(Cmp);
- assert(CheckTerm->isUnconditional());
+ TerminatorInst *CrashTerm = 0;
+
+ if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
+ 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
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