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Teach AddressSanitizer to create basic blocks in a more natural order.

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This is particularly useful to the backend code generators which try to
process things in the incoming function order.

Also, cleanup some uses of IRBuilder to be a bit simpler and more clear.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160254 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth 2012-07-16 08:58:53 +00:00
parent 2f58533d1e
commit c3c8db9d25
2 changed files with 27 additions and 29 deletions
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34
lib/Transforms/Instrumentation/AddressSanitizer.cpp
View File

@ -230,17 +230,17 @@ static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
// Returns the ThenBlock's terminator.
static BranchInst *splitBlockAndInsertIfThen(Value *Cmp) {
Instruction *SplitBefore = cast<Instruction>(Cmp)->getNextNode();
BasicBlock *Head = SplitBefore->getParent();
BasicBlock *Tail = Head->splitBasicBlock(SplitBefore);
TerminatorInst *HeadOldTerm = Head->getTerminator();
LLVMContext &C = Head->getParent()->getParent()->getContext();
BasicBlock *ThenBlock = BasicBlock::Create(C, "", Head->getParent());
BranchInst *HeadNewTerm =
BranchInst::Create(/*ifTrue*/ThenBlock, /*ifFalse*/Tail, Cmp);
ReplaceInstWithInst(HeadOldTerm, HeadNewTerm);
BranchInst *CheckTerm = BranchInst::Create(Tail, ThenBlock);
return CheckTerm;
// Create three basic blocks, with the middle block empty, by splitting twice.
BasicBlock *Head = SplitBefore->getParent();
BasicBlock *Then = Head->splitBasicBlock(SplitBefore);
BasicBlock *Tail = Then->splitBasicBlock(SplitBefore);
TerminatorInst *HeadOldTerm = Head->getTerminator();
IRBuilder<>(HeadOldTerm).CreateCondBr(Cmp, Then, Tail);
HeadOldTerm->eraseFromParent();
return cast<BranchInst>(Then->getTerminator());
}
Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
@ -387,28 +387,28 @@ void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
Instruction *CheckTerm = splitBlockAndInsertIfThen(Cmp);
IRBuilder<> IRB2(CheckTerm);
IRB.SetInsertPoint(CheckTerm);
size_t Granularity = 1 << MappingScale;
if (TypeSize < 8 * Granularity) {
// Addr & (Granularity - 1)
Value *LastAccessedByte = IRB2.CreateAnd(
Value *LastAccessedByte = IRB.CreateAnd(
AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
// (Addr & (Granularity - 1)) + size - 1
if (TypeSize / 8 > 1)
LastAccessedByte = IRB2.CreateAdd(
LastAccessedByte = IRB.CreateAdd(
LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
// (uint8_t) ((Addr & (Granularity-1)) + size - 1)
LastAccessedByte = IRB2.CreateIntCast(
LastAccessedByte = IRB.CreateIntCast(
LastAccessedByte, IRB.getInt8Ty(), false);
// ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
Value *Cmp2 = IRB2.CreateICmpSGE(LastAccessedByte, ShadowValue);
Value *Cmp2 = IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
CheckTerm = splitBlockAndInsertIfThen(Cmp2);
IRB.SetInsertPoint(CheckTerm);
}
IRBuilder<> IRB1(CheckTerm);
Instruction *Crash = generateCrashCode(IRB1, AddrLong, IsWrite, TypeSize);
Instruction *Crash = generateCrashCode(IRB, AddrLong, IsWrite, TypeSize);
Crash->setDebugLoc(OrigIns->getDebugLoc());
ReplaceInstWithInst(CheckTerm, new UnreachableInst(*C));
}

22
test/Instrumentation/AddressSanitizer/basic.ll
View File

@ -16,11 +16,6 @@ define i32 @test_load(i32* %a) address_safety {
; CHECK: icmp ne i8
; CHECK: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}
;
; The actual load comes next because ASan adds the last instrumentation block
; to the end of the function.
; CHECK: %tmp1 = load i32* %a
; CHECK: ret i32 %tmp1
;
; First instrumentation block refines the shadow test.
; CHECK: and i64 %[[LOAD_ADDR]], 7
; CHECK: add i64 %{{.*}}, 3
@ -28,9 +23,13 @@ define i32 @test_load(i32* %a) address_safety {
; CHECK: icmp sge i8 %{{.*}}, %[[LOAD_SHADOW]]
; CHECK: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}
;
; Final instrumentation block reports the error.
; Second instrumentation block reports the error.
; CHECK: call void @__asan_report_load4(i64 %[[LOAD_ADDR]]) noreturn
; CHECK: unreachable
;
; Finally the instrumented load.
; CHECK: %tmp1 = load i32* %a
; CHECK: ret i32 %tmp1
entry:
%tmp1 = load i32* %a
@ -48,11 +47,6 @@ define void @test_store(i32* %a) address_safety {
; CHECK: icmp ne i8
; CHECK: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}
;
; The actual store comes next because ASan adds the last instrumentation block
; to the end of the function.
; CHECK: store i32 42, i32* %a
; CHECK: ret void
;
; First instrumentation block refines the shadow test.
; CHECK: and i64 %[[STORE_ADDR]], 7
; CHECK: add i64 %{{.*}}, 3
@ -60,9 +54,13 @@ define void @test_store(i32* %a) address_safety {
; CHECK: icmp sge i8 %{{.*}}, %[[STORE_SHADOW]]
; CHECK: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}
;
; Final instrumentation block reports the error.
; Second instrumentation block reports the error.
; CHECK: call void @__asan_report_store4(i64 %[[STORE_ADDR]]) noreturn
; CHECK: unreachable
;
; Finally the instrumented store.
; CHECK: store i32 42, i32* %a
; CHECK: ret void
entry:
store i32 42, i32* %a