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[TSan] Fix atomicrmw xchg with pointer and floats #85228

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Mar 15, 2024
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[TSan] Fix atomicrmw xchg with pointer and floats #85228

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9 changes: 5 additions & 4 deletions llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -752,11 +752,12 @@ bool ThreadSanitizer::instrumentAtomic(Instruction *I, const DataLayout &DL) {
const unsigned ByteSize = 1U << Idx;
const unsigned BitSize = ByteSize * 8;
Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize);
Value *Args[] = {Addr,
IRB.CreateIntCast(RMWI->getValOperand(), Ty, false),
Value *Val = RMWI->getValOperand();
Value *Args[] = {Addr, IRB.CreateBitOrPointerCast(Val, Ty),
createOrdering(&IRB, RMWI->getOrdering())};
CallInst *C = CallInst::Create(F, Args);
ReplaceInstWithInst(I, C);
Value *C = IRB.CreateCall(F, Args);
I->replaceAllUsesWith(IRB.CreateBitOrPointerCast(C, Val->getType()));
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Looks like replaceAllUsesWith/eraseFromParent matches ReplaceInstWithInst
However, could we keep code consistent?
Replacing all places in a separate patch LGTM.

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The reason I changed this is that we now go through IRBuilder, which will insert the instructions itself, so we can no longer use ReplaceInstWithInst. This is also why the cmpxchg code does the same.

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Converted the remaining uses in 8a237ab.

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Thanks!

I->eraseFromParent();
} else if (AtomicCmpXchgInst *CASI = dyn_cast<AtomicCmpXchgInst>(I)) {
Value *Addr = CASI->getPointerOperand();
Type *OrigOldValTy = CASI->getNewValOperand()->getType();
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20 changes: 20 additions & 0 deletions llvm/test/Instrumentation/ThreadSanitizer/atomic.ll
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Expand Up @@ -78,6 +78,26 @@ entry:
; CHECK-LABEL: atomic8_xchg_monotonic
; CHECK: call i8 @__tsan_atomic8_exchange(ptr %a, i8 0, i32 0), !dbg

define void @atomic8_xchg_monotonic_ptr(ptr %a, ptr %b) nounwind uwtable {
entry:
atomicrmw xchg ptr %a, ptr %b monotonic, !dbg !7
ret void, !dbg !7
}
; CHECK-LABEL: atomic8_xchg_monotonic_ptr
; CHECK: [[ARG:%.*]] = ptrtoint ptr %b to i64, !dbg
; CHECK: [[RES:%.*]] = call i64 @__tsan_atomic64_exchange(ptr %a, i64 [[ARG]], i32 0), !dbg
; CHECK: [[CAST:%.*]] = inttoptr i64 [[RES]] to ptr, !dbg

define void @atomic8_xchg_monotonic_float(ptr %a, float %b) nounwind uwtable {
entry:
atomicrmw xchg ptr %a, float %b monotonic, !dbg !7
ret void, !dbg !7
}
; CHECK-LABEL: atomic8_xchg_monotonic_float
; CHECK: [[ARG:%.*]] = bitcast float %b to i32, !dbg
; CHECK: [[RES:%.*]] = call i32 @__tsan_atomic32_exchange(ptr %a, i32 [[ARG]], i32 0), !dbg
; CHECK: [[CAST:%.*]] = bitcast i32 [[RES]] to float, !dbg

define void @atomic8_add_monotonic(ptr %a) nounwind uwtable {
entry:
atomicrmw add ptr %a, i8 0 monotonic, !dbg !7
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