[asan] make sure that the crash callbacks do not get merged (Chandler's idea: insert an empty InlineAsm). Change the order in which the new BBs are inserted: the slow path BB is insert between old BBs, the crash BB is inserted at the end. Don't create an empty BB (introduced by recent commits). Update the test. The experimental code that does manual crash callback merge will most likely be deleted later.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160544 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 14348b9..3368026 100644
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -18,6 +18,7 @@
#include "FunctionBlackList.h"
#include "llvm/Function.h"
#include "llvm/IRBuilder.h"
+#include "llvm/InlineAsm.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
@@ -224,6 +225,7 @@
OwningPtr<FunctionBlackList> BL;
// This array is indexed by AccessIsWrite and log2(AccessSize).
Function *AsanErrorCallback[2][kNumberOfAccessSizes];
+ InlineAsm *EmptyAsm;
};
} // namespace
@@ -276,7 +278,7 @@
BranchInst *CheckTerm = 0;
if (!ThenBlock) {
LLVMContext &C = Head->getParent()->getParent()->getContext();
- ThenBlock = BasicBlock::Create(C, "", Head->getParent());
+ ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
CheckTerm = BranchInst::Create(Tail, ThenBlock);
}
BranchInst *HeadNewTerm =
@@ -414,7 +416,10 @@
Addr, PC);
else
Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex], Addr);
- Call->setDoesNotReturn();
+ // We don't do Call->setDoesNotReturn() because the BB already has
+ // UnreachableInst at the end.
+ // This EmptyAsm is required to avoid callback merge.
+ IRB.CreateCall(EmptyAsm);
return Call;
}
@@ -483,10 +488,13 @@
size_t Granularity = 1 << MappingScale;
if (TypeSize < 8 * Granularity) {
- Instruction *CheckTerm = splitBlockAndInsertIfThen(Cmp);
+ BranchInst *CheckTerm = splitBlockAndInsertIfThen(Cmp);
+ assert(CheckTerm->isUnconditional());
+ BasicBlock *NextBB = CheckTerm->getSuccessor(0);
IRB.SetInsertPoint(CheckTerm);
Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
- splitBlockAndInsertIfThen(Cmp2, CrashBlock);
+ BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
+ ReplaceInstWithInst(CheckTerm, NewTerm);
} else {
splitBlockAndInsertIfThen(Cmp, CrashBlock);
}
@@ -695,6 +703,10 @@
M.getOrInsertFunction(FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
}
}
+ // We insert an empty inline asm after __asan_report* to avoid callback merge.
+ EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
+ StringRef(""), StringRef(""),
+ /*hasSideEffects=*/true);
llvm::Triple targetTriple(M.getTargetTriple());
bool isAndroid = targetTriple.getEnvironment() == llvm::Triple::ANDROIDEABI;