1 //===-- MemorySanitizer.cpp - detector of uninitialized reads -------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 /// This file is a part of MemorySanitizer, a detector of uninitialized
13 /// Status: early prototype.
15 /// The algorithm of the tool is similar to Memcheck
16 /// (http://goo.gl/QKbem). We associate a few shadow bits with every
17 /// byte of the application memory, poison the shadow of the malloc-ed
18 /// or alloca-ed memory, load the shadow bits on every memory read,
19 /// propagate the shadow bits through some of the arithmetic
20 /// instruction (including MOV), store the shadow bits on every memory
21 /// write, report a bug on some other instructions (e.g. JMP) if the
22 /// associated shadow is poisoned.
24 /// But there are differences too. The first and the major one:
25 /// compiler instrumentation instead of binary instrumentation. This
26 /// gives us much better register allocation, possible compiler
27 /// optimizations and a fast start-up. But this brings the major issue
28 /// as well: msan needs to see all program events, including system
29 /// calls and reads/writes in system libraries, so we either need to
30 /// compile *everything* with msan or use a binary translation
31 /// component (e.g. DynamoRIO) to instrument pre-built libraries.
32 /// Another difference from Memcheck is that we use 8 shadow bits per
33 /// byte of application memory and use a direct shadow mapping. This
34 /// greatly simplifies the instrumentation code and avoids races on
35 /// shadow updates (Memcheck is single-threaded so races are not a
36 /// concern there. Memcheck uses 2 shadow bits per byte with a slow
37 /// path storage that uses 8 bits per byte).
39 /// The default value of shadow is 0, which means "clean" (not poisoned).
41 /// Every module initializer should call __msan_init to ensure that the
42 /// shadow memory is ready. On error, __msan_warning is called. Since
43 /// parameters and return values may be passed via registers, we have a
44 /// specialized thread-local shadow for return values
45 /// (__msan_retval_tls) and parameters (__msan_param_tls).
46 //===----------------------------------------------------------------------===//
48 #define DEBUG_TYPE "msan"
50 #include "llvm/Transforms/Instrumentation.h"
51 #include "BlackList.h"
52 #include "llvm/ADT/DepthFirstIterator.h"
53 #include "llvm/ADT/SmallString.h"
54 #include "llvm/ADT/SmallVector.h"
55 #include "llvm/ADT/ValueMap.h"
56 #include "llvm/DataLayout.h"
57 #include "llvm/Function.h"
58 #include "llvm/IRBuilder.h"
59 #include "llvm/InlineAsm.h"
60 #include "llvm/InstVisitor.h"
61 #include "llvm/IntrinsicInst.h"
62 #include "llvm/LLVMContext.h"
63 #include "llvm/MDBuilder.h"
64 #include "llvm/Module.h"
65 #include "llvm/Support/CommandLine.h"
66 #include "llvm/Support/Compiler.h"
67 #include "llvm/Support/Debug.h"
68 #include "llvm/Support/raw_ostream.h"
69 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
70 #include "llvm/Transforms/Utils/Local.h"
71 #include "llvm/Transforms/Utils/ModuleUtils.h"
72 #include "llvm/Type.h"
76 static const uint64_t kShadowMask32 = 1ULL << 31;
77 static const uint64_t kShadowMask64 = 1ULL << 46;
78 static const uint64_t kOriginOffset32 = 1ULL << 30;
79 static const uint64_t kOriginOffset64 = 1ULL << 45;
80 static const uint64_t kShadowTLSAlignment = 8;
82 // This is an important flag that makes the reports much more
83 // informative at the cost of greater slowdown. Not fully implemented
85 // FIXME: this should be a top-level clang flag, e.g.
86 // -fmemory-sanitizer-full.
87 static cl::opt<bool> ClTrackOrigins("msan-track-origins",
88 cl::desc("Track origins (allocation sites) of poisoned memory"),
89 cl::Hidden, cl::init(false));
90 static cl::opt<bool> ClKeepGoing("msan-keep-going",
91 cl::desc("keep going after reporting a UMR"),
92 cl::Hidden, cl::init(false));
93 static cl::opt<bool> ClPoisonStack("msan-poison-stack",
94 cl::desc("poison uninitialized stack variables"),
95 cl::Hidden, cl::init(true));
96 static cl::opt<bool> ClPoisonStackWithCall("msan-poison-stack-with-call",
97 cl::desc("poison uninitialized stack variables with a call"),
98 cl::Hidden, cl::init(false));
99 static cl::opt<int> ClPoisonStackPattern("msan-poison-stack-pattern",
100 cl::desc("poison uninitialized stack variables with the given patter"),
101 cl::Hidden, cl::init(0xff));
103 static cl::opt<bool> ClHandleICmp("msan-handle-icmp",
104 cl::desc("propagate shadow through ICmpEQ and ICmpNE"),
105 cl::Hidden, cl::init(true));
107 static cl::opt<bool> ClStoreCleanOrigin("msan-store-clean-origin",
108 cl::desc("store origin for clean (fully initialized) values"),
109 cl::Hidden, cl::init(false));
111 // This flag controls whether we check the shadow of the address
112 // operand of load or store. Such bugs are very rare, since load from
113 // a garbage address typically results in SEGV, but still happen
114 // (e.g. only lower bits of address are garbage, or the access happens
115 // early at program startup where malloc-ed memory is more likely to
116 // be zeroed. As of 2012-08-28 this flag adds 20% slowdown.
117 static cl::opt<bool> ClCheckAccessAddress("msan-check-access-address",
118 cl::desc("report accesses through a pointer which has poisoned shadow"),
119 cl::Hidden, cl::init(true));
121 static cl::opt<bool> ClDumpStrictInstructions("msan-dump-strict-instructions",
122 cl::desc("print out instructions with default strict semantics"),
123 cl::Hidden, cl::init(false));
125 static cl::opt<std::string> ClBlackListFile("msan-blacklist",
126 cl::desc("File containing the list of functions where MemorySanitizer "
127 "should not report bugs"), cl::Hidden);
131 /// \brief An instrumentation pass implementing detection of uninitialized
134 /// MemorySanitizer: instrument the code in module to find
135 /// uninitialized reads.
136 class MemorySanitizer : public FunctionPass {
138 MemorySanitizer(bool TrackOrigins = false)
140 TrackOrigins(TrackOrigins || ClTrackOrigins),
143 const char *getPassName() const { return "MemorySanitizer"; }
144 bool runOnFunction(Function &F);
145 bool doInitialization(Module &M);
146 static char ID; // Pass identification, replacement for typeid.
149 void initializeCallbacks(Module &M);
151 /// \brief Track origins (allocation points) of uninitialized values.
158 /// \brief Thread-local shadow storage for function parameters.
159 GlobalVariable *ParamTLS;
160 /// \brief Thread-local origin storage for function parameters.
161 GlobalVariable *ParamOriginTLS;
162 /// \brief Thread-local shadow storage for function return value.
163 GlobalVariable *RetvalTLS;
164 /// \brief Thread-local origin storage for function return value.
165 GlobalVariable *RetvalOriginTLS;
166 /// \brief Thread-local shadow storage for in-register va_arg function
167 /// parameters (x86_64-specific).
168 GlobalVariable *VAArgTLS;
169 /// \brief Thread-local shadow storage for va_arg overflow area
170 /// (x86_64-specific).
171 GlobalVariable *VAArgOverflowSizeTLS;
172 /// \brief Thread-local space used to pass origin value to the UMR reporting
174 GlobalVariable *OriginTLS;
176 /// \brief The run-time callback to print a warning.
178 /// \brief Run-time helper that copies origin info for a memory range.
179 Value *MsanCopyOriginFn;
180 /// \brief Run-time helper that generates a new origin value for a stack
182 Value *MsanSetAllocaOriginFn;
183 /// \brief Run-time helper that poisons stack on function entry.
184 Value *MsanPoisonStackFn;
185 /// \brief MSan runtime replacements for memmove, memcpy and memset.
186 Value *MemmoveFn, *MemcpyFn, *MemsetFn;
188 /// \brief Address mask used in application-to-shadow address calculation.
189 /// ShadowAddr is computed as ApplicationAddr & ~ShadowMask.
191 /// \brief Offset of the origin shadow from the "normal" shadow.
192 /// OriginAddr is computed as (ShadowAddr + OriginOffset) & ~3ULL
193 uint64_t OriginOffset;
194 /// \brief Branch weights for error reporting.
195 MDNode *ColdCallWeights;
196 /// \brief Branch weights for origin store.
197 MDNode *OriginStoreWeights;
198 /// \brief The blacklist.
199 OwningPtr<BlackList> BL;
200 /// \brief An empty volatile inline asm that prevents callback merge.
203 friend struct MemorySanitizerVisitor;
204 friend struct VarArgAMD64Helper;
208 char MemorySanitizer::ID = 0;
209 INITIALIZE_PASS(MemorySanitizer, "msan",
210 "MemorySanitizer: detects uninitialized reads.",
213 FunctionPass *llvm::createMemorySanitizerPass(bool TrackOrigins) {
214 return new MemorySanitizer(TrackOrigins);
217 /// \brief Create a non-const global initialized with the given string.
219 /// Creates a writable global for Str so that we can pass it to the
220 /// run-time lib. Runtime uses first 4 bytes of the string to store the
221 /// frame ID, so the string needs to be mutable.
222 static GlobalVariable *createPrivateNonConstGlobalForString(Module &M,
224 Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
225 return new GlobalVariable(M, StrConst->getType(), /*isConstant=*/false,
226 GlobalValue::PrivateLinkage, StrConst, "");
230 /// \brief Insert extern declaration of runtime-provided functions and globals.
231 void MemorySanitizer::initializeCallbacks(Module &M) {
232 // Only do this once.
237 // Create the callback.
238 // FIXME: this function should have "Cold" calling conv,
239 // which is not yet implemented.
240 StringRef WarningFnName = ClKeepGoing ? "__msan_warning"
241 : "__msan_warning_noreturn";
242 WarningFn = M.getOrInsertFunction(WarningFnName, IRB.getVoidTy(), NULL);
244 MsanCopyOriginFn = M.getOrInsertFunction(
245 "__msan_copy_origin", IRB.getVoidTy(), IRB.getInt8PtrTy(),
246 IRB.getInt8PtrTy(), IntptrTy, NULL);
247 MsanSetAllocaOriginFn = M.getOrInsertFunction(
248 "__msan_set_alloca_origin", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy,
249 IRB.getInt8PtrTy(), NULL);
250 MsanPoisonStackFn = M.getOrInsertFunction(
251 "__msan_poison_stack", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy, NULL);
252 MemmoveFn = M.getOrInsertFunction(
253 "__msan_memmove", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
254 IRB.getInt8PtrTy(), IntptrTy, NULL);
255 MemcpyFn = M.getOrInsertFunction(
256 "__msan_memcpy", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
258 MemsetFn = M.getOrInsertFunction(
259 "__msan_memset", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt32Ty(),
263 RetvalTLS = new GlobalVariable(
264 M, ArrayType::get(IRB.getInt64Ty(), 8), false,
265 GlobalVariable::ExternalLinkage, 0, "__msan_retval_tls", 0,
266 GlobalVariable::GeneralDynamicTLSModel);
267 RetvalOriginTLS = new GlobalVariable(
268 M, OriginTy, false, GlobalVariable::ExternalLinkage, 0,
269 "__msan_retval_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel);
271 ParamTLS = new GlobalVariable(
272 M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
273 GlobalVariable::ExternalLinkage, 0, "__msan_param_tls", 0,
274 GlobalVariable::GeneralDynamicTLSModel);
275 ParamOriginTLS = new GlobalVariable(
276 M, ArrayType::get(OriginTy, 1000), false, GlobalVariable::ExternalLinkage,
277 0, "__msan_param_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel);
279 VAArgTLS = new GlobalVariable(
280 M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
281 GlobalVariable::ExternalLinkage, 0, "__msan_va_arg_tls", 0,
282 GlobalVariable::GeneralDynamicTLSModel);
283 VAArgOverflowSizeTLS = new GlobalVariable(
284 M, IRB.getInt64Ty(), false, GlobalVariable::ExternalLinkage, 0,
285 "__msan_va_arg_overflow_size_tls", 0,
286 GlobalVariable::GeneralDynamicTLSModel);
287 OriginTLS = new GlobalVariable(
288 M, IRB.getInt32Ty(), false, GlobalVariable::ExternalLinkage, 0,
289 "__msan_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel);
291 // We insert an empty inline asm after __msan_report* to avoid callback merge.
292 EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
293 StringRef(""), StringRef(""),
294 /*hasSideEffects=*/true);
297 /// \brief Module-level initialization.
299 /// inserts a call to __msan_init to the module's constructor list.
300 bool MemorySanitizer::doInitialization(Module &M) {
301 TD = getAnalysisIfAvailable<DataLayout>();
304 BL.reset(new BlackList(ClBlackListFile));
305 C = &(M.getContext());
306 unsigned PtrSize = TD->getPointerSizeInBits(/* AddressSpace */0);
309 ShadowMask = kShadowMask64;
310 OriginOffset = kOriginOffset64;
313 ShadowMask = kShadowMask32;
314 OriginOffset = kOriginOffset32;
317 report_fatal_error("unsupported pointer size");
322 IntptrTy = IRB.getIntPtrTy(TD);
323 OriginTy = IRB.getInt32Ty();
325 ColdCallWeights = MDBuilder(*C).createBranchWeights(1, 1000);
326 OriginStoreWeights = MDBuilder(*C).createBranchWeights(1, 1000);
328 // Insert a call to __msan_init/__msan_track_origins into the module's CTORs.
329 appendToGlobalCtors(M, cast<Function>(M.getOrInsertFunction(
330 "__msan_init", IRB.getVoidTy(), NULL)), 0);
332 new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
333 IRB.getInt32(TrackOrigins), "__msan_track_origins");
340 /// \brief A helper class that handles instrumentation of VarArg
341 /// functions on a particular platform.
343 /// Implementations are expected to insert the instrumentation
344 /// necessary to propagate argument shadow through VarArg function
345 /// calls. Visit* methods are called during an InstVisitor pass over
346 /// the function, and should avoid creating new basic blocks. A new
347 /// instance of this class is created for each instrumented function.
348 struct VarArgHelper {
349 /// \brief Visit a CallSite.
350 virtual void visitCallSite(CallSite &CS, IRBuilder<> &IRB) = 0;
352 /// \brief Visit a va_start call.
353 virtual void visitVAStartInst(VAStartInst &I) = 0;
355 /// \brief Visit a va_copy call.
356 virtual void visitVACopyInst(VACopyInst &I) = 0;
358 /// \brief Finalize function instrumentation.
360 /// This method is called after visiting all interesting (see above)
361 /// instructions in a function.
362 virtual void finalizeInstrumentation() = 0;
364 virtual ~VarArgHelper() {}
367 struct MemorySanitizerVisitor;
370 CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
371 MemorySanitizerVisitor &Visitor);
373 /// This class does all the work for a given function. Store and Load
374 /// instructions store and load corresponding shadow and origin
375 /// values. Most instructions propagate shadow from arguments to their
376 /// return values. Certain instructions (most importantly, BranchInst)
377 /// test their argument shadow and print reports (with a runtime call) if it's
379 struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
382 SmallVector<PHINode *, 16> ShadowPHINodes, OriginPHINodes;
383 ValueMap<Value*, Value*> ShadowMap, OriginMap;
385 OwningPtr<VarArgHelper> VAHelper;
387 // An unfortunate workaround for asymmetric lowering of va_arg stuff.
388 // See a comment in visitCallSite for more details.
389 static const unsigned AMD64GpEndOffset = 48; // AMD64 ABI Draft 0.99.6 p3.5.7
390 static const unsigned AMD64FpEndOffset = 176;
392 struct ShadowOriginAndInsertPoint {
395 Instruction *OrigIns;
396 ShadowOriginAndInsertPoint(Instruction *S, Instruction *O, Instruction *I)
397 : Shadow(S), Origin(O), OrigIns(I) { }
398 ShadowOriginAndInsertPoint() : Shadow(0), Origin(0), OrigIns(0) { }
400 SmallVector<ShadowOriginAndInsertPoint, 16> InstrumentationList;
401 SmallVector<Instruction*, 16> StoreList;
403 MemorySanitizerVisitor(Function &F, MemorySanitizer &MS)
404 : F(F), MS(MS), VAHelper(CreateVarArgHelper(F, MS, *this)) {
405 InsertChecks = !MS.BL->isIn(F);
406 DEBUG(if (!InsertChecks)
407 dbgs() << "MemorySanitizer is not inserting checks into '"
408 << F.getName() << "'\n");
411 void materializeStores() {
412 for (size_t i = 0, n = StoreList.size(); i < n; i++) {
413 StoreInst& I = *dyn_cast<StoreInst>(StoreList[i]);
416 Value *Val = I.getValueOperand();
417 Value *Addr = I.getPointerOperand();
418 Value *Shadow = getShadow(Val);
419 Value *ShadowPtr = getShadowPtr(Addr, Shadow->getType(), IRB);
422 IRB.CreateAlignedStore(Shadow, ShadowPtr, I.getAlignment());
423 DEBUG(dbgs() << " STORE: " << *NewSI << "\n");
425 // If the store is volatile, add a check.
427 insertCheck(Val, &I);
428 if (ClCheckAccessAddress)
429 insertCheck(Addr, &I);
431 if (MS.TrackOrigins) {
432 if (ClStoreCleanOrigin || isa<StructType>(Shadow->getType())) {
433 IRB.CreateStore(getOrigin(Val), getOriginPtr(Addr, IRB));
435 Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
437 Constant *Cst = dyn_cast_or_null<Constant>(ConvertedShadow);
438 // TODO(eugenis): handle non-zero constant shadow by inserting an
439 // unconditional check (can not simply fail compilation as this could
440 // be in the dead code).
444 Value *Cmp = IRB.CreateICmpNE(ConvertedShadow,
445 getCleanShadow(ConvertedShadow), "_mscmp");
446 Instruction *CheckTerm =
447 SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false,
448 MS.OriginStoreWeights);
449 IRBuilder<> IRBNew(CheckTerm);
450 IRBNew.CreateStore(getOrigin(Val), getOriginPtr(Addr, IRBNew));
456 void materializeChecks() {
457 for (size_t i = 0, n = InstrumentationList.size(); i < n; i++) {
458 Instruction *Shadow = InstrumentationList[i].Shadow;
459 Instruction *OrigIns = InstrumentationList[i].OrigIns;
460 IRBuilder<> IRB(OrigIns);
461 DEBUG(dbgs() << " SHAD0 : " << *Shadow << "\n");
462 Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
463 DEBUG(dbgs() << " SHAD1 : " << *ConvertedShadow << "\n");
464 Value *Cmp = IRB.CreateICmpNE(ConvertedShadow,
465 getCleanShadow(ConvertedShadow), "_mscmp");
466 Instruction *CheckTerm =
467 SplitBlockAndInsertIfThen(cast<Instruction>(Cmp),
468 /* Unreachable */ !ClKeepGoing,
471 IRB.SetInsertPoint(CheckTerm);
472 if (MS.TrackOrigins) {
473 Instruction *Origin = InstrumentationList[i].Origin;
474 IRB.CreateStore(Origin ? (Value*)Origin : (Value*)IRB.getInt32(0),
477 CallInst *Call = IRB.CreateCall(MS.WarningFn);
478 Call->setDebugLoc(OrigIns->getDebugLoc());
479 IRB.CreateCall(MS.EmptyAsm);
480 DEBUG(dbgs() << " CHECK: " << *Cmp << "\n");
482 DEBUG(dbgs() << "DONE:\n" << F);
485 /// \brief Add MemorySanitizer instrumentation to a function.
486 bool runOnFunction() {
487 MS.initializeCallbacks(*F.getParent());
488 if (!MS.TD) return false;
490 // In the presence of unreachable blocks, we may see Phi nodes with
491 // incoming nodes from such blocks. Since InstVisitor skips unreachable
492 // blocks, such nodes will not have any shadow value associated with them.
493 // It's easier to remove unreachable blocks than deal with missing shadow.
494 removeUnreachableBlocks(F);
496 // Iterate all BBs in depth-first order and create shadow instructions
497 // for all instructions (where applicable).
498 // For PHI nodes we create dummy shadow PHIs which will be finalized later.
499 for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
500 DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) {
501 BasicBlock *BB = *DI;
505 // Finalize PHI nodes.
506 for (size_t i = 0, n = ShadowPHINodes.size(); i < n; i++) {
507 PHINode *PN = ShadowPHINodes[i];
508 PHINode *PNS = cast<PHINode>(getShadow(PN));
509 PHINode *PNO = MS.TrackOrigins ? cast<PHINode>(getOrigin(PN)) : 0;
510 size_t NumValues = PN->getNumIncomingValues();
511 for (size_t v = 0; v < NumValues; v++) {
512 PNS->addIncoming(getShadow(PN, v), PN->getIncomingBlock(v));
514 PNO->addIncoming(getOrigin(PN, v), PN->getIncomingBlock(v));
518 VAHelper->finalizeInstrumentation();
520 // Delayed instrumentation of StoreInst.
521 // This may add new checks to be inserted later.
524 // Insert shadow value checks.
530 /// \brief Compute the shadow type that corresponds to a given Value.
531 Type *getShadowTy(Value *V) {
532 return getShadowTy(V->getType());
535 /// \brief Compute the shadow type that corresponds to a given Type.
536 Type *getShadowTy(Type *OrigTy) {
537 if (!OrigTy->isSized()) {
540 // For integer type, shadow is the same as the original type.
541 // This may return weird-sized types like i1.
542 if (IntegerType *IT = dyn_cast<IntegerType>(OrigTy))
544 if (VectorType *VT = dyn_cast<VectorType>(OrigTy))
545 return VectorType::getInteger(VT);
546 if (StructType *ST = dyn_cast<StructType>(OrigTy)) {
547 SmallVector<Type*, 4> Elements;
548 for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
549 Elements.push_back(getShadowTy(ST->getElementType(i)));
550 StructType *Res = StructType::get(*MS.C, Elements, ST->isPacked());
551 DEBUG(dbgs() << "getShadowTy: " << *ST << " ===> " << *Res << "\n");
554 uint32_t TypeSize = MS.TD->getTypeStoreSizeInBits(OrigTy);
555 return IntegerType::get(*MS.C, TypeSize);
558 /// \brief Flatten a vector type.
559 Type *getShadowTyNoVec(Type *ty) {
560 if (VectorType *vt = dyn_cast<VectorType>(ty))
561 return IntegerType::get(*MS.C, vt->getBitWidth());
565 /// \brief Convert a shadow value to it's flattened variant.
566 Value *convertToShadowTyNoVec(Value *V, IRBuilder<> &IRB) {
567 Type *Ty = V->getType();
568 Type *NoVecTy = getShadowTyNoVec(Ty);
569 if (Ty == NoVecTy) return V;
570 return IRB.CreateBitCast(V, NoVecTy);
573 /// \brief Compute the shadow address that corresponds to a given application
576 /// Shadow = Addr & ~ShadowMask.
577 Value *getShadowPtr(Value *Addr, Type *ShadowTy,
580 IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
581 ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask));
582 return IRB.CreateIntToPtr(ShadowLong, PointerType::get(ShadowTy, 0));
585 /// \brief Compute the origin address that corresponds to a given application
588 /// OriginAddr = (ShadowAddr + OriginOffset) & ~3ULL
589 Value *getOriginPtr(Value *Addr, IRBuilder<> &IRB) {
591 IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
592 ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask));
594 IRB.CreateAdd(ShadowLong,
595 ConstantInt::get(MS.IntptrTy, MS.OriginOffset));
597 IRB.CreateAnd(Add, ConstantInt::get(MS.IntptrTy, ~3ULL));
598 return IRB.CreateIntToPtr(SecondAnd, PointerType::get(IRB.getInt32Ty(), 0));
601 /// \brief Compute the shadow address for a given function argument.
603 /// Shadow = ParamTLS+ArgOffset.
604 Value *getShadowPtrForArgument(Value *A, IRBuilder<> &IRB,
606 Value *Base = IRB.CreatePointerCast(MS.ParamTLS, MS.IntptrTy);
607 Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
608 return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A), 0),
612 /// \brief Compute the origin address for a given function argument.
613 Value *getOriginPtrForArgument(Value *A, IRBuilder<> &IRB,
615 if (!MS.TrackOrigins) return 0;
616 Value *Base = IRB.CreatePointerCast(MS.ParamOriginTLS, MS.IntptrTy);
617 Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
618 return IRB.CreateIntToPtr(Base, PointerType::get(MS.OriginTy, 0),
622 /// \brief Compute the shadow address for a retval.
623 Value *getShadowPtrForRetval(Value *A, IRBuilder<> &IRB) {
624 Value *Base = IRB.CreatePointerCast(MS.RetvalTLS, MS.IntptrTy);
625 return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A), 0),
629 /// \brief Compute the origin address for a retval.
630 Value *getOriginPtrForRetval(IRBuilder<> &IRB) {
631 // We keep a single origin for the entire retval. Might be too optimistic.
632 return MS.RetvalOriginTLS;
635 /// \brief Set SV to be the shadow value for V.
636 void setShadow(Value *V, Value *SV) {
637 assert(!ShadowMap.count(V) && "Values may only have one shadow");
641 /// \brief Set Origin to be the origin value for V.
642 void setOrigin(Value *V, Value *Origin) {
643 if (!MS.TrackOrigins) return;
644 assert(!OriginMap.count(V) && "Values may only have one origin");
645 DEBUG(dbgs() << "ORIGIN: " << *V << " ==> " << *Origin << "\n");
646 OriginMap[V] = Origin;
649 /// \brief Create a clean shadow value for a given value.
651 /// Clean shadow (all zeroes) means all bits of the value are defined
653 Value *getCleanShadow(Value *V) {
654 Type *ShadowTy = getShadowTy(V);
657 return Constant::getNullValue(ShadowTy);
660 /// \brief Create a dirty shadow of a given shadow type.
661 Constant *getPoisonedShadow(Type *ShadowTy) {
663 if (isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy))
664 return Constant::getAllOnesValue(ShadowTy);
665 StructType *ST = cast<StructType>(ShadowTy);
666 SmallVector<Constant *, 4> Vals;
667 for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
668 Vals.push_back(getPoisonedShadow(ST->getElementType(i)));
669 return ConstantStruct::get(ST, Vals);
672 /// \brief Create a clean (zero) origin.
673 Value *getCleanOrigin() {
674 return Constant::getNullValue(MS.OriginTy);
677 /// \brief Get the shadow value for a given Value.
679 /// This function either returns the value set earlier with setShadow,
680 /// or extracts if from ParamTLS (for function arguments).
681 Value *getShadow(Value *V) {
682 if (Instruction *I = dyn_cast<Instruction>(V)) {
683 // For instructions the shadow is already stored in the map.
684 Value *Shadow = ShadowMap[V];
686 DEBUG(dbgs() << "No shadow: " << *V << "\n" << *(I->getParent()));
688 assert(Shadow && "No shadow for a value");
692 if (UndefValue *U = dyn_cast<UndefValue>(V)) {
693 Value *AllOnes = getPoisonedShadow(getShadowTy(V));
694 DEBUG(dbgs() << "Undef: " << *U << " ==> " << *AllOnes << "\n");
698 if (Argument *A = dyn_cast<Argument>(V)) {
699 // For arguments we compute the shadow on demand and store it in the map.
700 Value **ShadowPtr = &ShadowMap[V];
703 Function *F = A->getParent();
704 IRBuilder<> EntryIRB(F->getEntryBlock().getFirstNonPHI());
705 unsigned ArgOffset = 0;
706 for (Function::arg_iterator AI = F->arg_begin(), AE = F->arg_end();
708 if (!AI->getType()->isSized()) {
709 DEBUG(dbgs() << "Arg is not sized\n");
712 unsigned Size = AI->hasByValAttr()
713 ? MS.TD->getTypeAllocSize(AI->getType()->getPointerElementType())
714 : MS.TD->getTypeAllocSize(AI->getType());
716 Value *Base = getShadowPtrForArgument(AI, EntryIRB, ArgOffset);
717 if (AI->hasByValAttr()) {
718 // ByVal pointer itself has clean shadow. We copy the actual
719 // argument shadow to the underlying memory.
720 Value *Cpy = EntryIRB.CreateMemCpy(
721 getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB),
722 Base, Size, AI->getParamAlignment());
723 DEBUG(dbgs() << " ByValCpy: " << *Cpy << "\n");
725 *ShadowPtr = getCleanShadow(V);
727 *ShadowPtr = EntryIRB.CreateLoad(Base);
729 DEBUG(dbgs() << " ARG: " << *AI << " ==> " <<
730 **ShadowPtr << "\n");
731 if (MS.TrackOrigins) {
732 Value* OriginPtr = getOriginPtrForArgument(AI, EntryIRB, ArgOffset);
733 setOrigin(A, EntryIRB.CreateLoad(OriginPtr));
736 ArgOffset += DataLayout::RoundUpAlignment(Size, 8);
738 assert(*ShadowPtr && "Could not find shadow for an argument");
741 // For everything else the shadow is zero.
742 return getCleanShadow(V);
745 /// \brief Get the shadow for i-th argument of the instruction I.
746 Value *getShadow(Instruction *I, int i) {
747 return getShadow(I->getOperand(i));
750 /// \brief Get the origin for a value.
751 Value *getOrigin(Value *V) {
752 if (!MS.TrackOrigins) return 0;
753 if (isa<Instruction>(V) || isa<Argument>(V)) {
754 Value *Origin = OriginMap[V];
756 DEBUG(dbgs() << "NO ORIGIN: " << *V << "\n");
757 Origin = getCleanOrigin();
761 return getCleanOrigin();
764 /// \brief Get the origin for i-th argument of the instruction I.
765 Value *getOrigin(Instruction *I, int i) {
766 return getOrigin(I->getOperand(i));
769 /// \brief Remember the place where a shadow check should be inserted.
771 /// This location will be later instrumented with a check that will print a
772 /// UMR warning in runtime if the value is not fully defined.
773 void insertCheck(Value *Val, Instruction *OrigIns) {
775 if (!InsertChecks) return;
776 Instruction *Shadow = dyn_cast_or_null<Instruction>(getShadow(Val));
779 Type *ShadowTy = Shadow->getType();
780 assert((isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy)) &&
781 "Can only insert checks for integer and vector shadow types");
783 Instruction *Origin = dyn_cast_or_null<Instruction>(getOrigin(Val));
784 InstrumentationList.push_back(
785 ShadowOriginAndInsertPoint(Shadow, Origin, OrigIns));
788 // ------------------- Visitors.
790 /// \brief Instrument LoadInst
792 /// Loads the corresponding shadow and (optionally) origin.
793 /// Optionally, checks that the load address is fully defined.
794 void visitLoadInst(LoadInst &I) {
795 assert(I.getType()->isSized() && "Load type must have size");
797 Type *ShadowTy = getShadowTy(&I);
798 Value *Addr = I.getPointerOperand();
799 Value *ShadowPtr = getShadowPtr(Addr, ShadowTy, IRB);
800 setShadow(&I, IRB.CreateAlignedLoad(ShadowPtr, I.getAlignment(), "_msld"));
802 if (ClCheckAccessAddress)
803 insertCheck(I.getPointerOperand(), &I);
806 setOrigin(&I, IRB.CreateLoad(getOriginPtr(Addr, IRB)));
809 /// \brief Instrument StoreInst
811 /// Stores the corresponding shadow and (optionally) origin.
812 /// Optionally, checks that the store address is fully defined.
813 /// Volatile stores check that the value being stored is fully defined.
814 void visitStoreInst(StoreInst &I) {
815 StoreList.push_back(&I);
818 // Vector manipulation.
819 void visitExtractElementInst(ExtractElementInst &I) {
820 insertCheck(I.getOperand(1), &I);
822 setShadow(&I, IRB.CreateExtractElement(getShadow(&I, 0), I.getOperand(1),
824 setOrigin(&I, getOrigin(&I, 0));
827 void visitInsertElementInst(InsertElementInst &I) {
828 insertCheck(I.getOperand(2), &I);
830 setShadow(&I, IRB.CreateInsertElement(getShadow(&I, 0), getShadow(&I, 1),
831 I.getOperand(2), "_msprop"));
832 setOriginForNaryOp(I);
835 void visitShuffleVectorInst(ShuffleVectorInst &I) {
836 insertCheck(I.getOperand(2), &I);
838 setShadow(&I, IRB.CreateShuffleVector(getShadow(&I, 0), getShadow(&I, 1),
839 I.getOperand(2), "_msprop"));
840 setOriginForNaryOp(I);
844 void visitSExtInst(SExtInst &I) {
846 setShadow(&I, IRB.CreateSExt(getShadow(&I, 0), I.getType(), "_msprop"));
847 setOrigin(&I, getOrigin(&I, 0));
850 void visitZExtInst(ZExtInst &I) {
852 setShadow(&I, IRB.CreateZExt(getShadow(&I, 0), I.getType(), "_msprop"));
853 setOrigin(&I, getOrigin(&I, 0));
856 void visitTruncInst(TruncInst &I) {
858 setShadow(&I, IRB.CreateTrunc(getShadow(&I, 0), I.getType(), "_msprop"));
859 setOrigin(&I, getOrigin(&I, 0));
862 void visitBitCastInst(BitCastInst &I) {
864 setShadow(&I, IRB.CreateBitCast(getShadow(&I, 0), getShadowTy(&I)));
865 setOrigin(&I, getOrigin(&I, 0));
868 void visitPtrToIntInst(PtrToIntInst &I) {
870 setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I), false,
871 "_msprop_ptrtoint"));
872 setOrigin(&I, getOrigin(&I, 0));
875 void visitIntToPtrInst(IntToPtrInst &I) {
877 setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I), false,
878 "_msprop_inttoptr"));
879 setOrigin(&I, getOrigin(&I, 0));
882 void visitFPToSIInst(CastInst& I) { handleShadowOr(I); }
883 void visitFPToUIInst(CastInst& I) { handleShadowOr(I); }
884 void visitSIToFPInst(CastInst& I) { handleShadowOr(I); }
885 void visitUIToFPInst(CastInst& I) { handleShadowOr(I); }
886 void visitFPExtInst(CastInst& I) { handleShadowOr(I); }
887 void visitFPTruncInst(CastInst& I) { handleShadowOr(I); }
889 /// \brief Propagate shadow for bitwise AND.
891 /// This code is exact, i.e. if, for example, a bit in the left argument
892 /// is defined and 0, then neither the value not definedness of the
893 /// corresponding bit in B don't affect the resulting shadow.
894 void visitAnd(BinaryOperator &I) {
896 // "And" of 0 and a poisoned value results in unpoisoned value.
897 // 1&1 => 1; 0&1 => 0; p&1 => p;
898 // 1&0 => 0; 0&0 => 0; p&0 => 0;
899 // 1&p => p; 0&p => 0; p&p => p;
900 // S = (S1 & S2) | (V1 & S2) | (S1 & V2)
901 Value *S1 = getShadow(&I, 0);
902 Value *S2 = getShadow(&I, 1);
903 Value *V1 = I.getOperand(0);
904 Value *V2 = I.getOperand(1);
905 if (V1->getType() != S1->getType()) {
906 V1 = IRB.CreateIntCast(V1, S1->getType(), false);
907 V2 = IRB.CreateIntCast(V2, S2->getType(), false);
909 Value *S1S2 = IRB.CreateAnd(S1, S2);
910 Value *V1S2 = IRB.CreateAnd(V1, S2);
911 Value *S1V2 = IRB.CreateAnd(S1, V2);
912 setShadow(&I, IRB.CreateOr(S1S2, IRB.CreateOr(V1S2, S1V2)));
913 setOriginForNaryOp(I);
916 void visitOr(BinaryOperator &I) {
918 // "Or" of 1 and a poisoned value results in unpoisoned value.
919 // 1|1 => 1; 0|1 => 1; p|1 => 1;
920 // 1|0 => 1; 0|0 => 0; p|0 => p;
921 // 1|p => 1; 0|p => p; p|p => p;
922 // S = (S1 & S2) | (~V1 & S2) | (S1 & ~V2)
923 Value *S1 = getShadow(&I, 0);
924 Value *S2 = getShadow(&I, 1);
925 Value *V1 = IRB.CreateNot(I.getOperand(0));
926 Value *V2 = IRB.CreateNot(I.getOperand(1));
927 if (V1->getType() != S1->getType()) {
928 V1 = IRB.CreateIntCast(V1, S1->getType(), false);
929 V2 = IRB.CreateIntCast(V2, S2->getType(), false);
931 Value *S1S2 = IRB.CreateAnd(S1, S2);
932 Value *V1S2 = IRB.CreateAnd(V1, S2);
933 Value *S1V2 = IRB.CreateAnd(S1, V2);
934 setShadow(&I, IRB.CreateOr(S1S2, IRB.CreateOr(V1S2, S1V2)));
935 setOriginForNaryOp(I);
938 /// \brief Default propagation of shadow and/or origin.
940 /// This class implements the general case of shadow propagation, used in all
941 /// cases where we don't know and/or don't care about what the operation
942 /// actually does. It converts all input shadow values to a common type
943 /// (extending or truncating as necessary), and bitwise OR's them.
945 /// This is much cheaper than inserting checks (i.e. requiring inputs to be
946 /// fully initialized), and less prone to false positives.
948 /// This class also implements the general case of origin propagation. For a
949 /// Nary operation, result origin is set to the origin of an argument that is
950 /// not entirely initialized. If there is more than one such arguments, the
951 /// rightmost of them is picked. It does not matter which one is picked if all
952 /// arguments are initialized.
953 template <bool CombineShadow>
958 MemorySanitizerVisitor *MSV;
961 Combiner(MemorySanitizerVisitor *MSV, IRBuilder<> &IRB) :
962 Shadow(0), Origin(0), IRB(IRB), MSV(MSV) {}
964 /// \brief Add a pair of shadow and origin values to the mix.
965 Combiner &Add(Value *OpShadow, Value *OpOrigin) {
971 OpShadow = MSV->CreateShadowCast(IRB, OpShadow, Shadow->getType());
972 Shadow = IRB.CreateOr(Shadow, OpShadow, "_msprop");
976 if (MSV->MS.TrackOrigins) {
981 Value *FlatShadow = MSV->convertToShadowTyNoVec(OpShadow, IRB);
982 Value *Cond = IRB.CreateICmpNE(FlatShadow,
983 MSV->getCleanShadow(FlatShadow));
984 Origin = IRB.CreateSelect(Cond, OpOrigin, Origin);
990 /// \brief Add an application value to the mix.
991 Combiner &Add(Value *V) {
992 Value *OpShadow = MSV->getShadow(V);
993 Value *OpOrigin = MSV->MS.TrackOrigins ? MSV->getOrigin(V) : 0;
994 return Add(OpShadow, OpOrigin);
997 /// \brief Set the current combined values as the given instruction's shadow
999 void Done(Instruction *I) {
1000 if (CombineShadow) {
1002 Shadow = MSV->CreateShadowCast(IRB, Shadow, MSV->getShadowTy(I));
1003 MSV->setShadow(I, Shadow);
1005 if (MSV->MS.TrackOrigins) {
1007 MSV->setOrigin(I, Origin);
1012 typedef Combiner<true> ShadowAndOriginCombiner;
1013 typedef Combiner<false> OriginCombiner;
1015 /// \brief Propagate origin for arbitrary operation.
1016 void setOriginForNaryOp(Instruction &I) {
1017 if (!MS.TrackOrigins) return;
1018 IRBuilder<> IRB(&I);
1019 OriginCombiner OC(this, IRB);
1020 for (Instruction::op_iterator OI = I.op_begin(); OI != I.op_end(); ++OI)
1025 size_t VectorOrPrimitiveTypeSizeInBits(Type *Ty) {
1026 return Ty->isVectorTy() ?
1027 Ty->getVectorNumElements() * Ty->getScalarSizeInBits() :
1028 Ty->getPrimitiveSizeInBits();
1031 /// \brief Cast between two shadow types, extending or truncating as
1033 Value *CreateShadowCast(IRBuilder<> &IRB, Value *V, Type *dstTy) {
1034 Type *srcTy = V->getType();
1035 if (dstTy->isIntegerTy() && srcTy->isIntegerTy())
1036 return IRB.CreateIntCast(V, dstTy, false);
1037 if (dstTy->isVectorTy() && srcTy->isVectorTy() &&
1038 dstTy->getVectorNumElements() == srcTy->getVectorNumElements())
1039 return IRB.CreateIntCast(V, dstTy, false);
1040 size_t srcSizeInBits = VectorOrPrimitiveTypeSizeInBits(srcTy);
1041 size_t dstSizeInBits = VectorOrPrimitiveTypeSizeInBits(dstTy);
1042 Value *V1 = IRB.CreateBitCast(V, Type::getIntNTy(*MS.C, srcSizeInBits));
1044 IRB.CreateIntCast(V1, Type::getIntNTy(*MS.C, dstSizeInBits), false);
1045 return IRB.CreateBitCast(V2, dstTy);
1046 // TODO: handle struct types.
1049 /// \brief Propagate shadow for arbitrary operation.
1050 void handleShadowOr(Instruction &I) {
1051 IRBuilder<> IRB(&I);
1052 ShadowAndOriginCombiner SC(this, IRB);
1053 for (Instruction::op_iterator OI = I.op_begin(); OI != I.op_end(); ++OI)
1058 void visitFAdd(BinaryOperator &I) { handleShadowOr(I); }
1059 void visitFSub(BinaryOperator &I) { handleShadowOr(I); }
1060 void visitFMul(BinaryOperator &I) { handleShadowOr(I); }
1061 void visitAdd(BinaryOperator &I) { handleShadowOr(I); }
1062 void visitSub(BinaryOperator &I) { handleShadowOr(I); }
1063 void visitXor(BinaryOperator &I) { handleShadowOr(I); }
1064 void visitMul(BinaryOperator &I) { handleShadowOr(I); }
1066 void handleDiv(Instruction &I) {
1067 IRBuilder<> IRB(&I);
1068 // Strict on the second argument.
1069 insertCheck(I.getOperand(1), &I);
1070 setShadow(&I, getShadow(&I, 0));
1071 setOrigin(&I, getOrigin(&I, 0));
1074 void visitUDiv(BinaryOperator &I) { handleDiv(I); }
1075 void visitSDiv(BinaryOperator &I) { handleDiv(I); }
1076 void visitFDiv(BinaryOperator &I) { handleDiv(I); }
1077 void visitURem(BinaryOperator &I) { handleDiv(I); }
1078 void visitSRem(BinaryOperator &I) { handleDiv(I); }
1079 void visitFRem(BinaryOperator &I) { handleDiv(I); }
1081 /// \brief Instrument == and != comparisons.
1083 /// Sometimes the comparison result is known even if some of the bits of the
1084 /// arguments are not.
1085 void handleEqualityComparison(ICmpInst &I) {
1086 IRBuilder<> IRB(&I);
1087 Value *A = I.getOperand(0);
1088 Value *B = I.getOperand(1);
1089 Value *Sa = getShadow(A);
1090 Value *Sb = getShadow(B);
1091 if (A->getType()->isPointerTy())
1092 A = IRB.CreatePointerCast(A, MS.IntptrTy);
1093 if (B->getType()->isPointerTy())
1094 B = IRB.CreatePointerCast(B, MS.IntptrTy);
1095 // A == B <==> (C = A^B) == 0
1096 // A != B <==> (C = A^B) != 0
1098 Value *C = IRB.CreateXor(A, B);
1099 Value *Sc = IRB.CreateOr(Sa, Sb);
1100 // Now dealing with i = (C == 0) comparison (or C != 0, does not matter now)
1101 // Result is defined if one of the following is true
1102 // * there is a defined 1 bit in C
1103 // * C is fully defined
1104 // Si = !(C & ~Sc) && Sc
1105 Value *Zero = Constant::getNullValue(Sc->getType());
1106 Value *MinusOne = Constant::getAllOnesValue(Sc->getType());
1108 IRB.CreateAnd(IRB.CreateICmpNE(Sc, Zero),
1110 IRB.CreateAnd(IRB.CreateXor(Sc, MinusOne), C), Zero));
1111 Si->setName("_msprop_icmp");
1113 setOriginForNaryOp(I);
1116 /// \brief Instrument signed relational comparisons.
1118 /// Handle (x<0) and (x>=0) comparisons (essentially, sign bit tests) by
1119 /// propagating the highest bit of the shadow. Everything else is delegated
1120 /// to handleShadowOr().
1121 void handleSignedRelationalComparison(ICmpInst &I) {
1122 Constant *constOp0 = dyn_cast<Constant>(I.getOperand(0));
1123 Constant *constOp1 = dyn_cast<Constant>(I.getOperand(1));
1125 CmpInst::Predicate pre = I.getPredicate();
1126 if (constOp0 && constOp0->isNullValue() &&
1127 (pre == CmpInst::ICMP_SGT || pre == CmpInst::ICMP_SLE)) {
1128 op = I.getOperand(1);
1129 } else if (constOp1 && constOp1->isNullValue() &&
1130 (pre == CmpInst::ICMP_SLT || pre == CmpInst::ICMP_SGE)) {
1131 op = I.getOperand(0);
1134 IRBuilder<> IRB(&I);
1136 IRB.CreateICmpSLT(getShadow(op), getCleanShadow(op), "_msprop_icmpslt");
1137 setShadow(&I, Shadow);
1138 setOrigin(&I, getOrigin(op));
1144 void visitICmpInst(ICmpInst &I) {
1145 if (ClHandleICmp && I.isEquality())
1146 handleEqualityComparison(I);
1147 else if (ClHandleICmp && I.isSigned() && I.isRelational())
1148 handleSignedRelationalComparison(I);
1153 void visitFCmpInst(FCmpInst &I) {
1157 void handleShift(BinaryOperator &I) {
1158 IRBuilder<> IRB(&I);
1159 // If any of the S2 bits are poisoned, the whole thing is poisoned.
1160 // Otherwise perform the same shift on S1.
1161 Value *S1 = getShadow(&I, 0);
1162 Value *S2 = getShadow(&I, 1);
1163 Value *S2Conv = IRB.CreateSExt(IRB.CreateICmpNE(S2, getCleanShadow(S2)),
1165 Value *V2 = I.getOperand(1);
1166 Value *Shift = IRB.CreateBinOp(I.getOpcode(), S1, V2);
1167 setShadow(&I, IRB.CreateOr(Shift, S2Conv));
1168 setOriginForNaryOp(I);
1171 void visitShl(BinaryOperator &I) { handleShift(I); }
1172 void visitAShr(BinaryOperator &I) { handleShift(I); }
1173 void visitLShr(BinaryOperator &I) { handleShift(I); }
1175 /// \brief Instrument llvm.memmove
1177 /// At this point we don't know if llvm.memmove will be inlined or not.
1178 /// If we don't instrument it and it gets inlined,
1179 /// our interceptor will not kick in and we will lose the memmove.
1180 /// If we instrument the call here, but it does not get inlined,
1181 /// we will memove the shadow twice: which is bad in case
1182 /// of overlapping regions. So, we simply lower the intrinsic to a call.
1184 /// Similar situation exists for memcpy and memset.
1185 void visitMemMoveInst(MemMoveInst &I) {
1186 IRBuilder<> IRB(&I);
1189 IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
1190 IRB.CreatePointerCast(I.getArgOperand(1), IRB.getInt8PtrTy()),
1191 IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false));
1192 I.eraseFromParent();
1195 // Similar to memmove: avoid copying shadow twice.
1196 // This is somewhat unfortunate as it may slowdown small constant memcpys.
1197 // FIXME: consider doing manual inline for small constant sizes and proper
1199 void visitMemCpyInst(MemCpyInst &I) {
1200 IRBuilder<> IRB(&I);
1203 IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
1204 IRB.CreatePointerCast(I.getArgOperand(1), IRB.getInt8PtrTy()),
1205 IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false));
1206 I.eraseFromParent();
1210 void visitMemSetInst(MemSetInst &I) {
1211 IRBuilder<> IRB(&I);
1214 IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
1215 IRB.CreateIntCast(I.getArgOperand(1), IRB.getInt32Ty(), false),
1216 IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false));
1217 I.eraseFromParent();
1220 void visitVAStartInst(VAStartInst &I) {
1221 VAHelper->visitVAStartInst(I);
1224 void visitVACopyInst(VACopyInst &I) {
1225 VAHelper->visitVACopyInst(I);
1228 enum IntrinsicKind {
1229 IK_DoesNotAccessMemory,
1234 static IntrinsicKind getIntrinsicKind(Intrinsic::ID iid) {
1235 const int DoesNotAccessMemory = IK_DoesNotAccessMemory;
1236 const int OnlyReadsArgumentPointees = IK_OnlyReadsMemory;
1237 const int OnlyReadsMemory = IK_OnlyReadsMemory;
1238 const int OnlyAccessesArgumentPointees = IK_WritesMemory;
1239 const int UnknownModRefBehavior = IK_WritesMemory;
1240 #define GET_INTRINSIC_MODREF_BEHAVIOR
1241 #define ModRefBehavior IntrinsicKind
1242 #include "llvm/Intrinsics.gen"
1243 #undef ModRefBehavior
1244 #undef GET_INTRINSIC_MODREF_BEHAVIOR
1247 /// \brief Handle vector store-like intrinsics.
1249 /// Instrument intrinsics that look like a simple SIMD store: writes memory,
1250 /// has 1 pointer argument and 1 vector argument, returns void.
1251 bool handleVectorStoreIntrinsic(IntrinsicInst &I) {
1252 IRBuilder<> IRB(&I);
1253 Value* Addr = I.getArgOperand(0);
1254 Value *Shadow = getShadow(&I, 1);
1255 Value *ShadowPtr = getShadowPtr(Addr, Shadow->getType(), IRB);
1257 // We don't know the pointer alignment (could be unaligned SSE store!).
1258 // Have to assume to worst case.
1259 IRB.CreateAlignedStore(Shadow, ShadowPtr, 1);
1261 if (ClCheckAccessAddress)
1262 insertCheck(Addr, &I);
1264 // FIXME: use ClStoreCleanOrigin
1265 // FIXME: factor out common code from materializeStores
1266 if (MS.TrackOrigins)
1267 IRB.CreateStore(getOrigin(&I, 1), getOriginPtr(Addr, IRB));
1271 /// \brief Handle vector load-like intrinsics.
1273 /// Instrument intrinsics that look like a simple SIMD load: reads memory,
1274 /// has 1 pointer argument, returns a vector.
1275 bool handleVectorLoadIntrinsic(IntrinsicInst &I) {
1276 IRBuilder<> IRB(&I);
1277 Value *Addr = I.getArgOperand(0);
1279 Type *ShadowTy = getShadowTy(&I);
1280 Value *ShadowPtr = getShadowPtr(Addr, ShadowTy, IRB);
1281 // We don't know the pointer alignment (could be unaligned SSE load!).
1282 // Have to assume to worst case.
1283 setShadow(&I, IRB.CreateAlignedLoad(ShadowPtr, 1, "_msld"));
1285 if (ClCheckAccessAddress)
1286 insertCheck(Addr, &I);
1288 if (MS.TrackOrigins)
1289 setOrigin(&I, IRB.CreateLoad(getOriginPtr(Addr, IRB)));
1293 /// \brief Handle (SIMD arithmetic)-like intrinsics.
1295 /// Instrument intrinsics with any number of arguments of the same type,
1296 /// equal to the return type. The type should be simple (no aggregates or
1297 /// pointers; vectors are fine).
1298 /// Caller guarantees that this intrinsic does not access memory.
1299 bool maybeHandleSimpleNomemIntrinsic(IntrinsicInst &I) {
1300 Type *RetTy = I.getType();
1301 if (!(RetTy->isIntOrIntVectorTy() ||
1302 RetTy->isFPOrFPVectorTy() ||
1303 RetTy->isX86_MMXTy()))
1306 unsigned NumArgOperands = I.getNumArgOperands();
1308 for (unsigned i = 0; i < NumArgOperands; ++i) {
1309 Type *Ty = I.getArgOperand(i)->getType();
1314 IRBuilder<> IRB(&I);
1315 ShadowAndOriginCombiner SC(this, IRB);
1316 for (unsigned i = 0; i < NumArgOperands; ++i)
1317 SC.Add(I.getArgOperand(i));
1323 /// \brief Heuristically instrument unknown intrinsics.
1325 /// The main purpose of this code is to do something reasonable with all
1326 /// random intrinsics we might encounter, most importantly - SIMD intrinsics.
1327 /// We recognize several classes of intrinsics by their argument types and
1328 /// ModRefBehaviour and apply special intrumentation when we are reasonably
1329 /// sure that we know what the intrinsic does.
1331 /// We special-case intrinsics where this approach fails. See llvm.bswap
1332 /// handling as an example of that.
1333 bool handleUnknownIntrinsic(IntrinsicInst &I) {
1334 unsigned NumArgOperands = I.getNumArgOperands();
1335 if (NumArgOperands == 0)
1338 Intrinsic::ID iid = I.getIntrinsicID();
1339 IntrinsicKind IK = getIntrinsicKind(iid);
1340 bool OnlyReadsMemory = IK == IK_OnlyReadsMemory;
1341 bool WritesMemory = IK == IK_WritesMemory;
1342 assert(!(OnlyReadsMemory && WritesMemory));
1344 if (NumArgOperands == 2 &&
1345 I.getArgOperand(0)->getType()->isPointerTy() &&
1346 I.getArgOperand(1)->getType()->isVectorTy() &&
1347 I.getType()->isVoidTy() &&
1349 // This looks like a vector store.
1350 return handleVectorStoreIntrinsic(I);
1353 if (NumArgOperands == 1 &&
1354 I.getArgOperand(0)->getType()->isPointerTy() &&
1355 I.getType()->isVectorTy() &&
1357 // This looks like a vector load.
1358 return handleVectorLoadIntrinsic(I);
1361 if (!OnlyReadsMemory && !WritesMemory)
1362 if (maybeHandleSimpleNomemIntrinsic(I))
1365 // FIXME: detect and handle SSE maskstore/maskload
1369 void handleBswap(IntrinsicInst &I) {
1370 IRBuilder<> IRB(&I);
1371 Value *Op = I.getArgOperand(0);
1372 Type *OpType = Op->getType();
1373 Function *BswapFunc = Intrinsic::getDeclaration(
1374 F.getParent(), Intrinsic::bswap, ArrayRef<Type*>(&OpType, 1));
1375 setShadow(&I, IRB.CreateCall(BswapFunc, getShadow(Op)));
1376 setOrigin(&I, getOrigin(Op));
1379 void visitIntrinsicInst(IntrinsicInst &I) {
1380 switch (I.getIntrinsicID()) {
1381 case llvm::Intrinsic::bswap:
1385 if (!handleUnknownIntrinsic(I))
1386 visitInstruction(I);
1391 void visitCallSite(CallSite CS) {
1392 Instruction &I = *CS.getInstruction();
1393 assert((CS.isCall() || CS.isInvoke()) && "Unknown type of CallSite");
1395 CallInst *Call = cast<CallInst>(&I);
1397 // For inline asm, do the usual thing: check argument shadow and mark all
1398 // outputs as clean. Note that any side effects of the inline asm that are
1399 // not immediately visible in its constraints are not handled.
1400 if (Call->isInlineAsm()) {
1401 visitInstruction(I);
1405 // Allow only tail calls with the same types, otherwise
1406 // we may have a false positive: shadow for a non-void RetVal
1407 // will get propagated to a void RetVal.
1408 if (Call->isTailCall() && Call->getType() != Call->getParent()->getType())
1409 Call->setTailCall(false);
1411 assert(!isa<IntrinsicInst>(&I) && "intrinsics are handled elsewhere");
1413 // We are going to insert code that relies on the fact that the callee
1414 // will become a non-readonly function after it is instrumented by us. To
1415 // prevent this code from being optimized out, mark that function
1416 // non-readonly in advance.
1417 if (Function *Func = Call->getCalledFunction()) {
1418 // Clear out readonly/readnone attributes.
1420 B.addAttribute(Attribute::ReadOnly)
1421 .addAttribute(Attribute::ReadNone);
1422 Func->removeAttribute(AttributeSet::FunctionIndex,
1423 Attribute::get(Func->getContext(), B));
1426 IRBuilder<> IRB(&I);
1427 unsigned ArgOffset = 0;
1428 DEBUG(dbgs() << " CallSite: " << I << "\n");
1429 for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end();
1430 ArgIt != End; ++ArgIt) {
1432 unsigned i = ArgIt - CS.arg_begin();
1433 if (!A->getType()->isSized()) {
1434 DEBUG(dbgs() << "Arg " << i << " is not sized: " << I << "\n");
1439 // Compute the Shadow for arg even if it is ByVal, because
1440 // in that case getShadow() will copy the actual arg shadow to
1441 // __msan_param_tls.
1442 Value *ArgShadow = getShadow(A);
1443 Value *ArgShadowBase = getShadowPtrForArgument(A, IRB, ArgOffset);
1444 DEBUG(dbgs() << " Arg#" << i << ": " << *A <<
1445 " Shadow: " << *ArgShadow << "\n");
1446 if (CS.paramHasAttr(i + 1, Attribute::ByVal)) {
1447 assert(A->getType()->isPointerTy() &&
1448 "ByVal argument is not a pointer!");
1449 Size = MS.TD->getTypeAllocSize(A->getType()->getPointerElementType());
1450 unsigned Alignment = CS.getParamAlignment(i + 1);
1451 Store = IRB.CreateMemCpy(ArgShadowBase,
1452 getShadowPtr(A, Type::getInt8Ty(*MS.C), IRB),
1455 Size = MS.TD->getTypeAllocSize(A->getType());
1456 Store = IRB.CreateAlignedStore(ArgShadow, ArgShadowBase,
1457 kShadowTLSAlignment);
1459 if (MS.TrackOrigins)
1460 IRB.CreateStore(getOrigin(A),
1461 getOriginPtrForArgument(A, IRB, ArgOffset));
1462 assert(Size != 0 && Store != 0);
1463 DEBUG(dbgs() << " Param:" << *Store << "\n");
1464 ArgOffset += DataLayout::RoundUpAlignment(Size, 8);
1466 DEBUG(dbgs() << " done with call args\n");
1469 cast<FunctionType>(CS.getCalledValue()->getType()-> getContainedType(0));
1470 if (FT->isVarArg()) {
1471 VAHelper->visitCallSite(CS, IRB);
1474 // Now, get the shadow for the RetVal.
1475 if (!I.getType()->isSized()) return;
1476 IRBuilder<> IRBBefore(&I);
1477 // Untill we have full dynamic coverage, make sure the retval shadow is 0.
1478 Value *Base = getShadowPtrForRetval(&I, IRBBefore);
1479 IRBBefore.CreateAlignedStore(getCleanShadow(&I), Base, kShadowTLSAlignment);
1480 Instruction *NextInsn = 0;
1482 NextInsn = I.getNextNode();
1484 BasicBlock *NormalDest = cast<InvokeInst>(&I)->getNormalDest();
1485 if (!NormalDest->getSinglePredecessor()) {
1486 // FIXME: this case is tricky, so we are just conservative here.
1487 // Perhaps we need to split the edge between this BB and NormalDest,
1488 // but a naive attempt to use SplitEdge leads to a crash.
1489 setShadow(&I, getCleanShadow(&I));
1490 setOrigin(&I, getCleanOrigin());
1493 NextInsn = NormalDest->getFirstInsertionPt();
1495 "Could not find insertion point for retval shadow load");
1497 IRBuilder<> IRBAfter(NextInsn);
1498 Value *RetvalShadow =
1499 IRBAfter.CreateAlignedLoad(getShadowPtrForRetval(&I, IRBAfter),
1500 kShadowTLSAlignment, "_msret");
1501 setShadow(&I, RetvalShadow);
1502 if (MS.TrackOrigins)
1503 setOrigin(&I, IRBAfter.CreateLoad(getOriginPtrForRetval(IRBAfter)));
1506 void visitReturnInst(ReturnInst &I) {
1507 IRBuilder<> IRB(&I);
1508 if (Value *RetVal = I.getReturnValue()) {
1509 // Set the shadow for the RetVal.
1510 Value *Shadow = getShadow(RetVal);
1511 Value *ShadowPtr = getShadowPtrForRetval(RetVal, IRB);
1512 DEBUG(dbgs() << "Return: " << *Shadow << "\n" << *ShadowPtr << "\n");
1513 IRB.CreateAlignedStore(Shadow, ShadowPtr, kShadowTLSAlignment);
1514 if (MS.TrackOrigins)
1515 IRB.CreateStore(getOrigin(RetVal), getOriginPtrForRetval(IRB));
1519 void visitPHINode(PHINode &I) {
1520 IRBuilder<> IRB(&I);
1521 ShadowPHINodes.push_back(&I);
1522 setShadow(&I, IRB.CreatePHI(getShadowTy(&I), I.getNumIncomingValues(),
1524 if (MS.TrackOrigins)
1525 setOrigin(&I, IRB.CreatePHI(MS.OriginTy, I.getNumIncomingValues(),
1529 void visitAllocaInst(AllocaInst &I) {
1530 setShadow(&I, getCleanShadow(&I));
1531 if (!ClPoisonStack) return;
1532 IRBuilder<> IRB(I.getNextNode());
1533 uint64_t Size = MS.TD->getTypeAllocSize(I.getAllocatedType());
1534 if (ClPoisonStackWithCall) {
1535 IRB.CreateCall2(MS.MsanPoisonStackFn,
1536 IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()),
1537 ConstantInt::get(MS.IntptrTy, Size));
1539 Value *ShadowBase = getShadowPtr(&I, Type::getInt8PtrTy(*MS.C), IRB);
1540 IRB.CreateMemSet(ShadowBase, IRB.getInt8(ClPoisonStackPattern),
1541 Size, I.getAlignment());
1544 if (MS.TrackOrigins) {
1545 setOrigin(&I, getCleanOrigin());
1546 SmallString<2048> StackDescriptionStorage;
1547 raw_svector_ostream StackDescription(StackDescriptionStorage);
1548 // We create a string with a description of the stack allocation and
1549 // pass it into __msan_set_alloca_origin.
1550 // It will be printed by the run-time if stack-originated UMR is found.
1551 // The first 4 bytes of the string are set to '----' and will be replaced
1552 // by __msan_va_arg_overflow_size_tls at the first call.
1553 StackDescription << "----" << I.getName() << "@" << F.getName();
1555 createPrivateNonConstGlobalForString(*F.getParent(),
1556 StackDescription.str());
1557 IRB.CreateCall3(MS.MsanSetAllocaOriginFn,
1558 IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()),
1559 ConstantInt::get(MS.IntptrTy, Size),
1560 IRB.CreatePointerCast(Descr, IRB.getInt8PtrTy()));
1564 void visitSelectInst(SelectInst& I) {
1565 IRBuilder<> IRB(&I);
1566 setShadow(&I, IRB.CreateSelect(I.getCondition(),
1567 getShadow(I.getTrueValue()), getShadow(I.getFalseValue()),
1569 if (MS.TrackOrigins)
1570 setOrigin(&I, IRB.CreateSelect(I.getCondition(),
1571 getOrigin(I.getTrueValue()), getOrigin(I.getFalseValue())));
1574 void visitLandingPadInst(LandingPadInst &I) {
1576 // See http://code.google.com/p/memory-sanitizer/issues/detail?id=1
1577 setShadow(&I, getCleanShadow(&I));
1578 setOrigin(&I, getCleanOrigin());
1581 void visitGetElementPtrInst(GetElementPtrInst &I) {
1585 void visitExtractValueInst(ExtractValueInst &I) {
1586 IRBuilder<> IRB(&I);
1587 Value *Agg = I.getAggregateOperand();
1588 DEBUG(dbgs() << "ExtractValue: " << I << "\n");
1589 Value *AggShadow = getShadow(Agg);
1590 DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n");
1591 Value *ResShadow = IRB.CreateExtractValue(AggShadow, I.getIndices());
1592 DEBUG(dbgs() << " ResShadow: " << *ResShadow << "\n");
1593 setShadow(&I, ResShadow);
1594 setOrigin(&I, getCleanOrigin());
1597 void visitInsertValueInst(InsertValueInst &I) {
1598 IRBuilder<> IRB(&I);
1599 DEBUG(dbgs() << "InsertValue: " << I << "\n");
1600 Value *AggShadow = getShadow(I.getAggregateOperand());
1601 Value *InsShadow = getShadow(I.getInsertedValueOperand());
1602 DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n");
1603 DEBUG(dbgs() << " InsShadow: " << *InsShadow << "\n");
1604 Value *Res = IRB.CreateInsertValue(AggShadow, InsShadow, I.getIndices());
1605 DEBUG(dbgs() << " Res: " << *Res << "\n");
1607 setOrigin(&I, getCleanOrigin());
1610 void dumpInst(Instruction &I) {
1611 if (CallInst *CI = dyn_cast<CallInst>(&I)) {
1612 errs() << "ZZZ call " << CI->getCalledFunction()->getName() << "\n";
1614 errs() << "ZZZ " << I.getOpcodeName() << "\n";
1616 errs() << "QQQ " << I << "\n";
1619 void visitResumeInst(ResumeInst &I) {
1620 DEBUG(dbgs() << "Resume: " << I << "\n");
1621 // Nothing to do here.
1624 void visitInstruction(Instruction &I) {
1625 // Everything else: stop propagating and check for poisoned shadow.
1626 if (ClDumpStrictInstructions)
1628 DEBUG(dbgs() << "DEFAULT: " << I << "\n");
1629 for (size_t i = 0, n = I.getNumOperands(); i < n; i++)
1630 insertCheck(I.getOperand(i), &I);
1631 setShadow(&I, getCleanShadow(&I));
1632 setOrigin(&I, getCleanOrigin());
1636 /// \brief AMD64-specific implementation of VarArgHelper.
1637 struct VarArgAMD64Helper : public VarArgHelper {
1638 // An unfortunate workaround for asymmetric lowering of va_arg stuff.
1639 // See a comment in visitCallSite for more details.
1640 static const unsigned AMD64GpEndOffset = 48; // AMD64 ABI Draft 0.99.6 p3.5.7
1641 static const unsigned AMD64FpEndOffset = 176;
1644 MemorySanitizer &MS;
1645 MemorySanitizerVisitor &MSV;
1646 Value *VAArgTLSCopy;
1647 Value *VAArgOverflowSize;
1649 SmallVector<CallInst*, 16> VAStartInstrumentationList;
1651 VarArgAMD64Helper(Function &F, MemorySanitizer &MS,
1652 MemorySanitizerVisitor &MSV)
1653 : F(F), MS(MS), MSV(MSV), VAArgTLSCopy(0), VAArgOverflowSize(0) { }
1655 enum ArgKind { AK_GeneralPurpose, AK_FloatingPoint, AK_Memory };
1657 ArgKind classifyArgument(Value* arg) {
1658 // A very rough approximation of X86_64 argument classification rules.
1659 Type *T = arg->getType();
1660 if (T->isFPOrFPVectorTy() || T->isX86_MMXTy())
1661 return AK_FloatingPoint;
1662 if (T->isIntegerTy() && T->getPrimitiveSizeInBits() <= 64)
1663 return AK_GeneralPurpose;
1664 if (T->isPointerTy())
1665 return AK_GeneralPurpose;
1669 // For VarArg functions, store the argument shadow in an ABI-specific format
1670 // that corresponds to va_list layout.
1671 // We do this because Clang lowers va_arg in the frontend, and this pass
1672 // only sees the low level code that deals with va_list internals.
1673 // A much easier alternative (provided that Clang emits va_arg instructions)
1674 // would have been to associate each live instance of va_list with a copy of
1675 // MSanParamTLS, and extract shadow on va_arg() call in the argument list
1677 void visitCallSite(CallSite &CS, IRBuilder<> &IRB) {
1678 unsigned GpOffset = 0;
1679 unsigned FpOffset = AMD64GpEndOffset;
1680 unsigned OverflowOffset = AMD64FpEndOffset;
1681 for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end();
1682 ArgIt != End; ++ArgIt) {
1684 ArgKind AK = classifyArgument(A);
1685 if (AK == AK_GeneralPurpose && GpOffset >= AMD64GpEndOffset)
1687 if (AK == AK_FloatingPoint && FpOffset >= AMD64FpEndOffset)
1691 case AK_GeneralPurpose:
1692 Base = getShadowPtrForVAArgument(A, IRB, GpOffset);
1695 case AK_FloatingPoint:
1696 Base = getShadowPtrForVAArgument(A, IRB, FpOffset);
1700 uint64_t ArgSize = MS.TD->getTypeAllocSize(A->getType());
1701 Base = getShadowPtrForVAArgument(A, IRB, OverflowOffset);
1702 OverflowOffset += DataLayout::RoundUpAlignment(ArgSize, 8);
1704 IRB.CreateAlignedStore(MSV.getShadow(A), Base, kShadowTLSAlignment);
1706 Constant *OverflowSize =
1707 ConstantInt::get(IRB.getInt64Ty(), OverflowOffset - AMD64FpEndOffset);
1708 IRB.CreateStore(OverflowSize, MS.VAArgOverflowSizeTLS);
1711 /// \brief Compute the shadow address for a given va_arg.
1712 Value *getShadowPtrForVAArgument(Value *A, IRBuilder<> &IRB,
1714 Value *Base = IRB.CreatePointerCast(MS.VAArgTLS, MS.IntptrTy);
1715 Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
1716 return IRB.CreateIntToPtr(Base, PointerType::get(MSV.getShadowTy(A), 0),
1720 void visitVAStartInst(VAStartInst &I) {
1721 IRBuilder<> IRB(&I);
1722 VAStartInstrumentationList.push_back(&I);
1723 Value *VAListTag = I.getArgOperand(0);
1724 Value *ShadowPtr = MSV.getShadowPtr(VAListTag, IRB.getInt8Ty(), IRB);
1726 // Unpoison the whole __va_list_tag.
1727 // FIXME: magic ABI constants.
1728 IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
1729 /* size */24, /* alignment */16, false);
1732 void visitVACopyInst(VACopyInst &I) {
1733 IRBuilder<> IRB(&I);
1734 Value *VAListTag = I.getArgOperand(0);
1735 Value *ShadowPtr = MSV.getShadowPtr(VAListTag, IRB.getInt8Ty(), IRB);
1737 // Unpoison the whole __va_list_tag.
1738 // FIXME: magic ABI constants.
1739 IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
1740 /* size */ 24, /* alignment */ 16, false);
1743 void finalizeInstrumentation() {
1744 assert(!VAArgOverflowSize && !VAArgTLSCopy &&
1745 "finalizeInstrumentation called twice");
1746 if (!VAStartInstrumentationList.empty()) {
1747 // If there is a va_start in this function, make a backup copy of
1748 // va_arg_tls somewhere in the function entry block.
1749 IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
1750 VAArgOverflowSize = IRB.CreateLoad(MS.VAArgOverflowSizeTLS);
1752 IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, AMD64FpEndOffset),
1754 VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
1755 IRB.CreateMemCpy(VAArgTLSCopy, MS.VAArgTLS, CopySize, 8);
1758 // Instrument va_start.
1759 // Copy va_list shadow from the backup copy of the TLS contents.
1760 for (size_t i = 0, n = VAStartInstrumentationList.size(); i < n; i++) {
1761 CallInst *OrigInst = VAStartInstrumentationList[i];
1762 IRBuilder<> IRB(OrigInst->getNextNode());
1763 Value *VAListTag = OrigInst->getArgOperand(0);
1765 Value *RegSaveAreaPtrPtr =
1767 IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
1768 ConstantInt::get(MS.IntptrTy, 16)),
1769 Type::getInt64PtrTy(*MS.C));
1770 Value *RegSaveAreaPtr = IRB.CreateLoad(RegSaveAreaPtrPtr);
1771 Value *RegSaveAreaShadowPtr =
1772 MSV.getShadowPtr(RegSaveAreaPtr, IRB.getInt8Ty(), IRB);
1773 IRB.CreateMemCpy(RegSaveAreaShadowPtr, VAArgTLSCopy,
1774 AMD64FpEndOffset, 16);
1776 Value *OverflowArgAreaPtrPtr =
1778 IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
1779 ConstantInt::get(MS.IntptrTy, 8)),
1780 Type::getInt64PtrTy(*MS.C));
1781 Value *OverflowArgAreaPtr = IRB.CreateLoad(OverflowArgAreaPtrPtr);
1782 Value *OverflowArgAreaShadowPtr =
1783 MSV.getShadowPtr(OverflowArgAreaPtr, IRB.getInt8Ty(), IRB);
1785 getShadowPtrForVAArgument(VAArgTLSCopy, IRB, AMD64FpEndOffset);
1786 IRB.CreateMemCpy(OverflowArgAreaShadowPtr, SrcPtr, VAArgOverflowSize, 16);
1791 VarArgHelper* CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
1792 MemorySanitizerVisitor &Visitor) {
1793 return new VarArgAMD64Helper(Func, Msan, Visitor);
1798 bool MemorySanitizer::runOnFunction(Function &F) {
1799 MemorySanitizerVisitor Visitor(F, *this);
1801 // Clear out readonly/readnone attributes.
1803 B.addAttribute(Attribute::ReadOnly)
1804 .addAttribute(Attribute::ReadNone);
1805 F.removeAttribute(AttributeSet::FunctionIndex,
1806 Attribute::get(F.getContext(), B));
1808 return Visitor.runOnFunction();