[PATCH] D63472: hwasan: Use llvm.read_register intrinsic to read the PC on aarch64 instead of taking the function's address.
Peter Collingbourne via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Mon Jun 17 20:39:29 PDT 2019
pcc created this revision.
pcc added a reviewer: eugenis.
Herald added subscribers: hiraditya, kristof.beyls, javed.absar.
Herald added a project: LLVM.
This shaves an instruction (and a GOT entry in PIC code) off prologues of
functions with stack variables.
Depends on D63469 <https://reviews.llvm.org/D63469>
Depends on D63471 <https://reviews.llvm.org/D63471>
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D63472
Files:
llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
Index: llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -205,6 +205,7 @@
SmallVectorImpl<AllocaInst *> &Allocas,
DenseMap<AllocaInst *, std::vector<DbgDeclareInst *>> &AllocaDeclareMap,
SmallVectorImpl<Instruction *> &RetVec, Value *StackTag);
+ Value *readRegister(IRBuilder<> &IRB, StringRef Name);
bool instrumentLandingPads(SmallVectorImpl<Instruction *> &RetVec);
Value *getNextTagWithCall(IRBuilder<> &IRB);
Value *getStackBaseTag(IRBuilder<> &IRB);
@@ -858,7 +859,11 @@
StackBaseTag = IRB.CreateAShr(ThreadLong, 3);
// Prepare ring buffer data.
- auto PC = IRB.CreatePtrToInt(F, IntptrTy);
+ Value *PC;
+ if (TargetTriple.getArch() == Triple::aarch64)
+ PC = readRegister(IRB, "pc");
+ else
+ PC = IRB.CreatePtrToInt(F, IntptrTy);
auto GetStackPointerFn =
Intrinsic::getDeclaration(F->getParent(), Intrinsic::frameaddress);
Value *SP = IRB.CreatePtrToInt(
@@ -904,19 +909,23 @@
LocalDynamicShadow = IRB.CreateIntToPtr(LocalDynamicShadow, Int8PtrTy);
}
-bool HWAddressSanitizer::instrumentLandingPads(
- SmallVectorImpl<Instruction *> &LandingPadVec) {
- Module *M = LandingPadVec[0]->getModule();
+Value *HWAddressSanitizer::readRegister(IRBuilder<> &IRB, StringRef Name) {
+ Module *M = IRB.GetInsertBlock()->getParent()->getParent();
Function *ReadRegister =
Intrinsic::getDeclaration(M, Intrinsic::read_register, IntptrTy);
- const char *RegName =
- (TargetTriple.getArch() == Triple::x86_64) ? "rsp" : "sp";
- MDNode *MD = MDNode::get(*C, {MDString::get(*C, RegName)});
+ MDNode *MD = MDNode::get(*C, {MDString::get(*C, Name)});
Value *Args[] = {MetadataAsValue::get(*C, MD)};
+ return IRB.CreateCall(ReadRegister, Args);
+}
+bool HWAddressSanitizer::instrumentLandingPads(
+ SmallVectorImpl<Instruction *> &LandingPadVec) {
for (auto *LP : LandingPadVec) {
IRBuilder<> IRB(LP->getNextNode());
- IRB.CreateCall(HWAsanHandleVfork, {IRB.CreateCall(ReadRegister, Args)});
+ IRB.CreateCall(
+ HWAsanHandleVfork,
+ {readRegister(IRB, (TargetTriple.getArch() == Triple::x86_64) ? "rsp"
+ : "sp")});
}
return true;
}
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