[llvm] r178230 - [tsan] make sure memset/memcpy/memmove are not inlined in tsan mode
Kostya Serebryany
kcc at google.com
Thu Mar 28 04:21:13 PDT 2013
Author: kcc
Date: Thu Mar 28 06:21:13 2013
New Revision: 178230
URL: http://llvm.org/viewvc/llvm-project?rev=178230&view=rev
Log:
[tsan] make sure memset/memcpy/memmove are not inlined in tsan mode
Modified:
llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
llvm/trunk/test/Instrumentation/ThreadSanitizer/tsan_basic.ll
Modified: llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp?rev=178230&r1=178229&r2=178230&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/ThreadSanitizer.cpp Thu Mar 28 06:21:13 2013
@@ -30,6 +30,7 @@
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Metadata.h"
@@ -56,6 +57,9 @@ static cl::opt<bool> ClInstrumentFuncEn
static cl::opt<bool> ClInstrumentAtomics(
"tsan-instrument-atomics", cl::init(true),
cl::desc("Instrument atomics"), cl::Hidden);
+static cl::opt<bool> ClInstrumentMemIntrinsics(
+ "tsan-instrument-memintrinsics", cl::init(true),
+ cl::desc("Instrument memintrinsics (memset/memcpy/memmove)"), cl::Hidden);
STATISTIC(NumInstrumentedReads, "Number of instrumented reads");
STATISTIC(NumInstrumentedWrites, "Number of instrumented writes");
@@ -86,12 +90,14 @@ struct ThreadSanitizer : public Function
void initializeCallbacks(Module &M);
bool instrumentLoadOrStore(Instruction *I);
bool instrumentAtomic(Instruction *I);
+ bool instrumentMemIntrinsic(Instruction *I);
void chooseInstructionsToInstrument(SmallVectorImpl<Instruction*> &Local,
SmallVectorImpl<Instruction*> &All);
bool addrPointsToConstantData(Value *Addr);
int getMemoryAccessFuncIndex(Value *Addr);
DataLayout *TD;
+ Type *IntptrTy;
SmallString<64> BlacklistFile;
OwningPtr<BlackList> BL;
IntegerType *OrdTy;
@@ -110,6 +116,7 @@ struct ThreadSanitizer : public Function
Function *TsanAtomicSignalFence;
Function *TsanVptrUpdate;
Function *TsanVptrLoad;
+ Function *MemmoveFn, *MemcpyFn, *MemsetFn;
};
} // namespace
@@ -204,6 +211,16 @@ void ThreadSanitizer::initializeCallback
"__tsan_atomic_thread_fence", IRB.getVoidTy(), OrdTy, NULL));
TsanAtomicSignalFence = checkInterfaceFunction(M.getOrInsertFunction(
"__tsan_atomic_signal_fence", IRB.getVoidTy(), OrdTy, NULL));
+
+ MemmoveFn = checkInterfaceFunction(M.getOrInsertFunction(
+ "memmove", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
+ IRB.getInt8PtrTy(), IntptrTy, NULL));
+ MemcpyFn = checkInterfaceFunction(M.getOrInsertFunction(
+ "memcpy", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
+ IntptrTy, NULL));
+ MemsetFn = checkInterfaceFunction(M.getOrInsertFunction(
+ "memset", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt32Ty(),
+ IntptrTy, NULL));
}
bool ThreadSanitizer::doInitialization(Module &M) {
@@ -214,6 +231,7 @@ bool ThreadSanitizer::doInitialization(M
// Always insert a call to __tsan_init into the module's CTORs.
IRBuilder<> IRB(M.getContext());
+ IntptrTy = IRB.getIntPtrTy(TD);
Value *TsanInit = M.getOrInsertFunction("__tsan_init",
IRB.getVoidTy(), NULL);
appendToGlobalCtors(M, cast<Function>(TsanInit), 0);
@@ -313,6 +331,7 @@ bool ThreadSanitizer::runOnFunction(Func
SmallVector<Instruction*, 8> AllLoadsAndStores;
SmallVector<Instruction*, 8> LocalLoadsAndStores;
SmallVector<Instruction*, 8> AtomicAccesses;
+ SmallVector<Instruction*, 8> MemIntrinCalls;
bool Res = false;
bool HasCalls = false;
@@ -329,6 +348,8 @@ bool ThreadSanitizer::runOnFunction(Func
else if (isa<ReturnInst>(BI))
RetVec.push_back(BI);
else if (isa<CallInst>(BI) || isa<InvokeInst>(BI)) {
+ if (isa<MemIntrinsic>(BI))
+ MemIntrinCalls.push_back(BI);
HasCalls = true;
chooseInstructionsToInstrument(LocalLoadsAndStores, AllLoadsAndStores);
}
@@ -352,6 +373,11 @@ bool ThreadSanitizer::runOnFunction(Func
Res |= instrumentAtomic(AtomicAccesses[i]);
}
+ if (ClInstrumentMemIntrinsics)
+ for (size_t i = 0, n = MemIntrinCalls.size(); i < n; ++i) {
+ Res |= instrumentMemIntrinsic(MemIntrinCalls[i]);
+ }
+
// Instrument function entry/exit points if there were instrumented accesses.
if ((Res || HasCalls) && ClInstrumentFuncEntryExit) {
IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
@@ -433,6 +459,32 @@ static ConstantInt *createFailOrdering(I
return IRB->getInt32(v);
}
+// If a memset intrinsic gets inlined by the code gen, we will miss races on it.
+// So, we either need to ensure the intrinsic is not inlined, or instrument it.
+// We do not instrument memset/memmove/memcpy intrinsics (too complicated),
+// instead we simply replace them with regular function calls, which are then
+// intercepted by the run-time.
+// Since tsan is running after everyone else, the calls should not be
+// replaced back with intrinsics. If that becomes wrong at some point,
+// we will need to call e.g. __tsan_memset to avoid the intrinsics.
+bool ThreadSanitizer::instrumentMemIntrinsic(Instruction *I) {
+ IRBuilder<> IRB(I);
+ if (MemSetInst *M = dyn_cast<MemSetInst>(I)) {
+ IRB.CreateCall3(MemsetFn,
+ IRB.CreatePointerCast(M->getArgOperand(0), IRB.getInt8PtrTy()),
+ IRB.CreateIntCast(M->getArgOperand(1), IRB.getInt32Ty(), false),
+ IRB.CreateIntCast(M->getArgOperand(2), IntptrTy, false));
+ I->eraseFromParent();
+ } else if (MemTransferInst *M = dyn_cast<MemTransferInst>(I)) {
+ IRB.CreateCall3(isa<MemCpyInst>(M) ? MemcpyFn : MemmoveFn,
+ IRB.CreatePointerCast(M->getArgOperand(0), IRB.getInt8PtrTy()),
+ IRB.CreatePointerCast(M->getArgOperand(1), IRB.getInt8PtrTy()),
+ IRB.CreateIntCast(M->getArgOperand(2), IntptrTy, false));
+ I->eraseFromParent();
+ }
+ return false;
+}
+
// Both llvm and ThreadSanitizer atomic operations are based on C++11/C1x
// standards. For background see C++11 standard. A slightly older, publically
// available draft of the standard (not entirely up-to-date, but close enough
Modified: llvm/trunk/test/Instrumentation/ThreadSanitizer/tsan_basic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/ThreadSanitizer/tsan_basic.ll?rev=178230&r1=178229&r2=178230&view=diff
==============================================================================
--- llvm/trunk/test/Instrumentation/ThreadSanitizer/tsan_basic.ll (original)
+++ llvm/trunk/test/Instrumentation/ThreadSanitizer/tsan_basic.ll Thu Mar 28 06:21:13 2013
@@ -20,3 +20,36 @@ entry:
; CHECK: ret i32
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1)
+declare void @llvm.memmove.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1)
+declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1)
+
+
+; Check that tsan converts mem intrinsics back to function calls.
+
+define void @MemCpyTest(i8* nocapture %x, i8* nocapture %y) {
+entry:
+ tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %x, i8* %y, i64 16, i32 4, i1 false)
+ ret void
+; CHECK: define void @MemCpyTest
+; CHECK: call i8* @memcpy
+; CHECK: ret void
+}
+
+define void @MemMoveTest(i8* nocapture %x, i8* nocapture %y) {
+entry:
+ tail call void @llvm.memmove.p0i8.p0i8.i64(i8* %x, i8* %y, i64 16, i32 4, i1 false)
+ ret void
+; CHECK: define void @MemMoveTest
+; CHECK: call i8* @memmove
+; CHECK: ret void
+}
+
+define void @MemSetTest(i8* nocapture %x) {
+entry:
+ tail call void @llvm.memset.p0i8.i64(i8* %x, i8 77, i64 16, i32 4, i1 false)
+ ret void
+; CHECK define void @MemSetTest
+; CHECK: call i8* @memset
+; CHECK: ret void
+}
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