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 /// The algorithm of the tool is similar to Memcheck
14 /// (http://goo.gl/QKbem). We associate a few shadow bits with every
15 /// byte of the application memory, poison the shadow of the malloc-ed
16 /// or alloca-ed memory, load the shadow bits on every memory read,
17 /// propagate the shadow bits through some of the arithmetic
18 /// instruction (including MOV), store the shadow bits on every memory
19 /// write, report a bug on some other instructions (e.g. JMP) if the
20 /// associated shadow is poisoned.
22 /// But there are differences too. The first and the major one:
23 /// compiler instrumentation instead of binary instrumentation. This
24 /// gives us much better register allocation, possible compiler
25 /// optimizations and a fast start-up. But this brings the major issue
26 /// as well: msan needs to see all program events, including system
27 /// calls and reads/writes in system libraries, so we either need to
28 /// compile *everything* with msan or use a binary translation
29 /// component (e.g. DynamoRIO) to instrument pre-built libraries.
30 /// Another difference from Memcheck is that we use 8 shadow bits per
31 /// byte of application memory and use a direct shadow mapping. This
32 /// greatly simplifies the instrumentation code and avoids races on
33 /// shadow updates (Memcheck is single-threaded so races are not a
34 /// concern there. Memcheck uses 2 shadow bits per byte with a slow
35 /// path storage that uses 8 bits per byte).
37 /// The default value of shadow is 0, which means "clean" (not poisoned).
39 /// Every module initializer should call __msan_init to ensure that the
40 /// shadow memory is ready. On error, __msan_warning is called. Since
41 /// parameters and return values may be passed via registers, we have a
42 /// specialized thread-local shadow for return values
43 /// (__msan_retval_tls) and parameters (__msan_param_tls).
47 /// MemorySanitizer can track origins (allocation points) of all uninitialized
48 /// values. This behavior is controlled with a flag (msan-track-origins) and is
49 /// disabled by default.
51 /// Origins are 4-byte values created and interpreted by the runtime library.
52 /// They are stored in a second shadow mapping, one 4-byte value for 4 bytes
53 /// of application memory. Propagation of origins is basically a bunch of
54 /// "select" instructions that pick the origin of a dirty argument, if an
55 /// instruction has one.
57 /// Every 4 aligned, consecutive bytes of application memory have one origin
58 /// value associated with them. If these bytes contain uninitialized data
59 /// coming from 2 different allocations, the last store wins. Because of this,
60 /// MemorySanitizer reports can show unrelated origins, but this is unlikely in
63 /// Origins are meaningless for fully initialized values, so MemorySanitizer
64 /// avoids storing origin to memory when a fully initialized value is stored.
65 /// This way it avoids needless overwritting origin of the 4-byte region on
66 /// a short (i.e. 1 byte) clean store, and it is also good for performance.
70 /// Ideally, every atomic store of application value should update the
71 /// corresponding shadow location in an atomic way. Unfortunately, atomic store
72 /// of two disjoint locations can not be done without severe slowdown.
74 /// Therefore, we implement an approximation that may err on the safe side.
75 /// In this implementation, every atomically accessed location in the program
76 /// may only change from (partially) uninitialized to fully initialized, but
77 /// not the other way around. We load the shadow _after_ the application load,
78 /// and we store the shadow _before_ the app store. Also, we always store clean
79 /// shadow (if the application store is atomic). This way, if the store-load
80 /// pair constitutes a happens-before arc, shadow store and load are correctly
81 /// ordered such that the load will get either the value that was stored, or
82 /// some later value (which is always clean).
84 /// This does not work very well with Compare-And-Swap (CAS) and
85 /// Read-Modify-Write (RMW) operations. To follow the above logic, CAS and RMW
86 /// must store the new shadow before the app operation, and load the shadow
87 /// after the app operation. Computers don't work this way. Current
88 /// implementation ignores the load aspect of CAS/RMW, always returning a clean
89 /// value. It implements the store part as a simple atomic store by storing a
92 //===----------------------------------------------------------------------===//
94 #include "llvm/Transforms/Instrumentation.h"
95 #include "llvm/ADT/DepthFirstIterator.h"
96 #include "llvm/ADT/SmallString.h"
97 #include "llvm/ADT/SmallVector.h"
98 #include "llvm/ADT/StringExtras.h"
99 #include "llvm/ADT/Triple.h"
100 #include "llvm/IR/DataLayout.h"
101 #include "llvm/IR/Function.h"
102 #include "llvm/IR/IRBuilder.h"
103 #include "llvm/IR/InlineAsm.h"
104 #include "llvm/IR/InstVisitor.h"
105 #include "llvm/IR/IntrinsicInst.h"
106 #include "llvm/IR/LLVMContext.h"
107 #include "llvm/IR/MDBuilder.h"
108 #include "llvm/IR/Module.h"
109 #include "llvm/IR/Type.h"
110 #include "llvm/IR/ValueMap.h"
111 #include "llvm/Support/CommandLine.h"
112 #include "llvm/Support/Compiler.h"
113 #include "llvm/Support/Debug.h"
114 #include "llvm/Support/raw_ostream.h"
115 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
116 #include "llvm/Transforms/Utils/Local.h"
117 #include "llvm/Transforms/Utils/ModuleUtils.h"
119 using namespace llvm;
121 #define DEBUG_TYPE "msan"
123 static const uint64_t kShadowMask32 = 1ULL << 31;
124 static const uint64_t kShadowMask64 = 1ULL << 46;
125 static const uint64_t kOriginOffset32 = 1ULL << 30;
126 static const uint64_t kOriginOffset64 = 1ULL << 45;
127 static const unsigned kMinOriginAlignment = 4;
128 static const unsigned kShadowTLSAlignment = 8;
130 // Accesses sizes are powers of two: 1, 2, 4, 8.
131 static const size_t kNumberOfAccessSizes = 4;
133 /// \brief Track origins of uninitialized values.
135 /// Adds a section to MemorySanitizer report that points to the allocation
136 /// (stack or heap) the uninitialized bits came from originally.
137 static cl::opt<int> ClTrackOrigins("msan-track-origins",
138 cl::desc("Track origins (allocation sites) of poisoned memory"),
139 cl::Hidden, cl::init(0));
140 static cl::opt<bool> ClKeepGoing("msan-keep-going",
141 cl::desc("keep going after reporting a UMR"),
142 cl::Hidden, cl::init(false));
143 static cl::opt<bool> ClPoisonStack("msan-poison-stack",
144 cl::desc("poison uninitialized stack variables"),
145 cl::Hidden, cl::init(true));
146 static cl::opt<bool> ClPoisonStackWithCall("msan-poison-stack-with-call",
147 cl::desc("poison uninitialized stack variables with a call"),
148 cl::Hidden, cl::init(false));
149 static cl::opt<int> ClPoisonStackPattern("msan-poison-stack-pattern",
150 cl::desc("poison uninitialized stack variables with the given patter"),
151 cl::Hidden, cl::init(0xff));
152 static cl::opt<bool> ClPoisonUndef("msan-poison-undef",
153 cl::desc("poison undef temps"),
154 cl::Hidden, cl::init(true));
156 static cl::opt<bool> ClHandleICmp("msan-handle-icmp",
157 cl::desc("propagate shadow through ICmpEQ and ICmpNE"),
158 cl::Hidden, cl::init(true));
160 static cl::opt<bool> ClHandleICmpExact("msan-handle-icmp-exact",
161 cl::desc("exact handling of relational integer ICmp"),
162 cl::Hidden, cl::init(false));
164 // This flag controls whether we check the shadow of the address
165 // operand of load or store. Such bugs are very rare, since load from
166 // a garbage address typically results in SEGV, but still happen
167 // (e.g. only lower bits of address are garbage, or the access happens
168 // early at program startup where malloc-ed memory is more likely to
169 // be zeroed. As of 2012-08-28 this flag adds 20% slowdown.
170 static cl::opt<bool> ClCheckAccessAddress("msan-check-access-address",
171 cl::desc("report accesses through a pointer which has poisoned shadow"),
172 cl::Hidden, cl::init(true));
174 static cl::opt<bool> ClDumpStrictInstructions("msan-dump-strict-instructions",
175 cl::desc("print out instructions with default strict semantics"),
176 cl::Hidden, cl::init(false));
178 static cl::opt<int> ClInstrumentationWithCallThreshold(
179 "msan-instrumentation-with-call-threshold",
181 "If the function being instrumented requires more than "
182 "this number of checks and origin stores, use callbacks instead of "
183 "inline checks (-1 means never use callbacks)."),
184 cl::Hidden, cl::init(3500));
186 // Experimental. Wraps all indirect calls in the instrumented code with
187 // a call to the given function. This is needed to assist the dynamic
188 // helper tool (MSanDR) to regain control on transition between instrumented and
189 // non-instrumented code.
190 static cl::opt<std::string> ClWrapIndirectCalls("msan-wrap-indirect-calls",
191 cl::desc("Wrap indirect calls with a given function"),
194 static cl::opt<bool> ClWrapIndirectCallsFast("msan-wrap-indirect-calls-fast",
195 cl::desc("Do not wrap indirect calls with target in the same module"),
196 cl::Hidden, cl::init(true));
200 /// \brief An instrumentation pass implementing detection of uninitialized
203 /// MemorySanitizer: instrument the code in module to find
204 /// uninitialized reads.
205 class MemorySanitizer : public FunctionPass {
207 MemorySanitizer(int TrackOrigins = 0)
209 TrackOrigins(std::max(TrackOrigins, (int)ClTrackOrigins)),
212 WrapIndirectCalls(!ClWrapIndirectCalls.empty()) {}
213 const char *getPassName() const override { return "MemorySanitizer"; }
214 bool runOnFunction(Function &F) override;
215 bool doInitialization(Module &M) override;
216 static char ID; // Pass identification, replacement for typeid.
219 void initializeCallbacks(Module &M);
221 /// \brief Track origins (allocation points) of uninitialized values.
224 const DataLayout *DL;
228 /// \brief Thread-local shadow storage for function parameters.
229 GlobalVariable *ParamTLS;
230 /// \brief Thread-local origin storage for function parameters.
231 GlobalVariable *ParamOriginTLS;
232 /// \brief Thread-local shadow storage for function return value.
233 GlobalVariable *RetvalTLS;
234 /// \brief Thread-local origin storage for function return value.
235 GlobalVariable *RetvalOriginTLS;
236 /// \brief Thread-local shadow storage for in-register va_arg function
237 /// parameters (x86_64-specific).
238 GlobalVariable *VAArgTLS;
239 /// \brief Thread-local shadow storage for va_arg overflow area
240 /// (x86_64-specific).
241 GlobalVariable *VAArgOverflowSizeTLS;
242 /// \brief Thread-local space used to pass origin value to the UMR reporting
244 GlobalVariable *OriginTLS;
246 GlobalVariable *MsandrModuleStart;
247 GlobalVariable *MsandrModuleEnd;
249 /// \brief The run-time callback to print a warning.
251 // These arrays are indexed by log2(AccessSize).
252 Value *MaybeWarningFn[kNumberOfAccessSizes];
253 Value *MaybeStoreOriginFn[kNumberOfAccessSizes];
255 /// \brief Run-time helper that generates a new origin value for a stack
257 Value *MsanSetAllocaOrigin4Fn;
258 /// \brief Run-time helper that poisons stack on function entry.
259 Value *MsanPoisonStackFn;
260 /// \brief Run-time helper that records a store (or any event) of an
261 /// uninitialized value and returns an updated origin id encoding this info.
262 Value *MsanChainOriginFn;
263 /// \brief MSan runtime replacements for memmove, memcpy and memset.
264 Value *MemmoveFn, *MemcpyFn, *MemsetFn;
266 /// \brief Address mask used in application-to-shadow address calculation.
267 /// ShadowAddr is computed as ApplicationAddr & ~ShadowMask.
269 /// \brief Offset of the origin shadow from the "normal" shadow.
270 /// OriginAddr is computed as (ShadowAddr + OriginOffset) & ~3ULL
271 uint64_t OriginOffset;
272 /// \brief Branch weights for error reporting.
273 MDNode *ColdCallWeights;
274 /// \brief Branch weights for origin store.
275 MDNode *OriginStoreWeights;
276 /// \brief An empty volatile inline asm that prevents callback merge.
279 bool WrapIndirectCalls;
280 /// \brief Run-time wrapper for indirect calls.
281 Value *IndirectCallWrapperFn;
282 // Argument and return type of IndirectCallWrapperFn: void (*f)(void).
283 Type *AnyFunctionPtrTy;
285 friend struct MemorySanitizerVisitor;
286 friend struct VarArgAMD64Helper;
290 char MemorySanitizer::ID = 0;
291 INITIALIZE_PASS(MemorySanitizer, "msan",
292 "MemorySanitizer: detects uninitialized reads.",
295 FunctionPass *llvm::createMemorySanitizerPass(int TrackOrigins) {
296 return new MemorySanitizer(TrackOrigins);
299 /// \brief Create a non-const global initialized with the given string.
301 /// Creates a writable global for Str so that we can pass it to the
302 /// run-time lib. Runtime uses first 4 bytes of the string to store the
303 /// frame ID, so the string needs to be mutable.
304 static GlobalVariable *createPrivateNonConstGlobalForString(Module &M,
306 Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
307 return new GlobalVariable(M, StrConst->getType(), /*isConstant=*/false,
308 GlobalValue::PrivateLinkage, StrConst, "");
312 /// \brief Insert extern declaration of runtime-provided functions and globals.
313 void MemorySanitizer::initializeCallbacks(Module &M) {
314 // Only do this once.
319 // Create the callback.
320 // FIXME: this function should have "Cold" calling conv,
321 // which is not yet implemented.
322 StringRef WarningFnName = ClKeepGoing ? "__msan_warning"
323 : "__msan_warning_noreturn";
324 WarningFn = M.getOrInsertFunction(WarningFnName, IRB.getVoidTy(), NULL);
326 for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
328 unsigned AccessSize = 1 << AccessSizeIndex;
329 std::string FunctionName = "__msan_maybe_warning_" + itostr(AccessSize);
330 MaybeWarningFn[AccessSizeIndex] = M.getOrInsertFunction(
331 FunctionName, IRB.getVoidTy(), IRB.getIntNTy(AccessSize * 8),
332 IRB.getInt32Ty(), NULL);
334 FunctionName = "__msan_maybe_store_origin_" + itostr(AccessSize);
335 MaybeStoreOriginFn[AccessSizeIndex] = M.getOrInsertFunction(
336 FunctionName, IRB.getVoidTy(), IRB.getIntNTy(AccessSize * 8),
337 IRB.getInt8PtrTy(), IRB.getInt32Ty(), NULL);
340 MsanSetAllocaOrigin4Fn = M.getOrInsertFunction(
341 "__msan_set_alloca_origin4", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy,
342 IRB.getInt8PtrTy(), IntptrTy, NULL);
343 MsanPoisonStackFn = M.getOrInsertFunction(
344 "__msan_poison_stack", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy, NULL);
345 MsanChainOriginFn = M.getOrInsertFunction(
346 "__msan_chain_origin", IRB.getInt32Ty(), IRB.getInt32Ty(), NULL);
347 MemmoveFn = M.getOrInsertFunction(
348 "__msan_memmove", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
349 IRB.getInt8PtrTy(), IntptrTy, NULL);
350 MemcpyFn = M.getOrInsertFunction(
351 "__msan_memcpy", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
353 MemsetFn = M.getOrInsertFunction(
354 "__msan_memset", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt32Ty(),
358 RetvalTLS = new GlobalVariable(
359 M, ArrayType::get(IRB.getInt64Ty(), 8), false,
360 GlobalVariable::ExternalLinkage, nullptr, "__msan_retval_tls", nullptr,
361 GlobalVariable::InitialExecTLSModel);
362 RetvalOriginTLS = new GlobalVariable(
363 M, OriginTy, false, GlobalVariable::ExternalLinkage, nullptr,
364 "__msan_retval_origin_tls", nullptr, GlobalVariable::InitialExecTLSModel);
366 ParamTLS = new GlobalVariable(
367 M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
368 GlobalVariable::ExternalLinkage, nullptr, "__msan_param_tls", nullptr,
369 GlobalVariable::InitialExecTLSModel);
370 ParamOriginTLS = new GlobalVariable(
371 M, ArrayType::get(OriginTy, 1000), false, GlobalVariable::ExternalLinkage,
372 nullptr, "__msan_param_origin_tls", nullptr,
373 GlobalVariable::InitialExecTLSModel);
375 VAArgTLS = new GlobalVariable(
376 M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
377 GlobalVariable::ExternalLinkage, nullptr, "__msan_va_arg_tls", nullptr,
378 GlobalVariable::InitialExecTLSModel);
379 VAArgOverflowSizeTLS = new GlobalVariable(
380 M, IRB.getInt64Ty(), false, GlobalVariable::ExternalLinkage, nullptr,
381 "__msan_va_arg_overflow_size_tls", nullptr,
382 GlobalVariable::InitialExecTLSModel);
383 OriginTLS = new GlobalVariable(
384 M, IRB.getInt32Ty(), false, GlobalVariable::ExternalLinkage, nullptr,
385 "__msan_origin_tls", nullptr, GlobalVariable::InitialExecTLSModel);
387 // We insert an empty inline asm after __msan_report* to avoid callback merge.
388 EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
389 StringRef(""), StringRef(""),
390 /*hasSideEffects=*/true);
392 if (WrapIndirectCalls) {
394 PointerType::getUnqual(FunctionType::get(IRB.getVoidTy(), false));
395 IndirectCallWrapperFn = M.getOrInsertFunction(
396 ClWrapIndirectCalls, AnyFunctionPtrTy, AnyFunctionPtrTy, NULL);
399 if (WrapIndirectCalls && ClWrapIndirectCallsFast) {
400 MsandrModuleStart = new GlobalVariable(
401 M, IRB.getInt32Ty(), false, GlobalValue::ExternalLinkage,
402 nullptr, "__executable_start");
403 MsandrModuleStart->setVisibility(GlobalVariable::HiddenVisibility);
404 MsandrModuleEnd = new GlobalVariable(
405 M, IRB.getInt32Ty(), false, GlobalValue::ExternalLinkage,
407 MsandrModuleEnd->setVisibility(GlobalVariable::HiddenVisibility);
411 /// \brief Module-level initialization.
413 /// inserts a call to __msan_init to the module's constructor list.
414 bool MemorySanitizer::doInitialization(Module &M) {
415 DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
417 report_fatal_error("data layout missing");
418 DL = &DLP->getDataLayout();
420 C = &(M.getContext());
421 unsigned PtrSize = DL->getPointerSizeInBits(/* AddressSpace */0);
424 ShadowMask = kShadowMask64;
425 OriginOffset = kOriginOffset64;
428 ShadowMask = kShadowMask32;
429 OriginOffset = kOriginOffset32;
432 report_fatal_error("unsupported pointer size");
437 IntptrTy = IRB.getIntPtrTy(DL);
438 OriginTy = IRB.getInt32Ty();
440 ColdCallWeights = MDBuilder(*C).createBranchWeights(1, 1000);
441 OriginStoreWeights = MDBuilder(*C).createBranchWeights(1, 1000);
443 // Insert a call to __msan_init/__msan_track_origins into the module's CTORs.
444 appendToGlobalCtors(M, cast<Function>(M.getOrInsertFunction(
445 "__msan_init", IRB.getVoidTy(), NULL)), 0);
448 new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
449 IRB.getInt32(TrackOrigins), "__msan_track_origins");
452 new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
453 IRB.getInt32(ClKeepGoing), "__msan_keep_going");
460 /// \brief A helper class that handles instrumentation of VarArg
461 /// functions on a particular platform.
463 /// Implementations are expected to insert the instrumentation
464 /// necessary to propagate argument shadow through VarArg function
465 /// calls. Visit* methods are called during an InstVisitor pass over
466 /// the function, and should avoid creating new basic blocks. A new
467 /// instance of this class is created for each instrumented function.
468 struct VarArgHelper {
469 /// \brief Visit a CallSite.
470 virtual void visitCallSite(CallSite &CS, IRBuilder<> &IRB) = 0;
472 /// \brief Visit a va_start call.
473 virtual void visitVAStartInst(VAStartInst &I) = 0;
475 /// \brief Visit a va_copy call.
476 virtual void visitVACopyInst(VACopyInst &I) = 0;
478 /// \brief Finalize function instrumentation.
480 /// This method is called after visiting all interesting (see above)
481 /// instructions in a function.
482 virtual void finalizeInstrumentation() = 0;
484 virtual ~VarArgHelper() {}
487 struct MemorySanitizerVisitor;
490 CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
491 MemorySanitizerVisitor &Visitor);
493 unsigned TypeSizeToSizeIndex(unsigned TypeSize) {
494 if (TypeSize <= 8) return 0;
495 return Log2_32_Ceil(TypeSize / 8);
498 /// This class does all the work for a given function. Store and Load
499 /// instructions store and load corresponding shadow and origin
500 /// values. Most instructions propagate shadow from arguments to their
501 /// return values. Certain instructions (most importantly, BranchInst)
502 /// test their argument shadow and print reports (with a runtime call) if it's
504 struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
507 SmallVector<PHINode *, 16> ShadowPHINodes, OriginPHINodes;
508 ValueMap<Value*, Value*> ShadowMap, OriginMap;
509 std::unique_ptr<VarArgHelper> VAHelper;
511 // The following flags disable parts of MSan instrumentation based on
512 // blacklist contents and command-line options.
517 bool CheckReturnValue;
519 struct ShadowOriginAndInsertPoint {
522 Instruction *OrigIns;
523 ShadowOriginAndInsertPoint(Value *S, Value *O, Instruction *I)
524 : Shadow(S), Origin(O), OrigIns(I) { }
526 SmallVector<ShadowOriginAndInsertPoint, 16> InstrumentationList;
527 SmallVector<Instruction*, 16> StoreList;
528 SmallVector<CallSite, 16> IndirectCallList;
530 MemorySanitizerVisitor(Function &F, MemorySanitizer &MS)
531 : F(F), MS(MS), VAHelper(CreateVarArgHelper(F, MS, *this)) {
532 bool SanitizeFunction = F.getAttributes().hasAttribute(
533 AttributeSet::FunctionIndex, Attribute::SanitizeMemory);
534 InsertChecks = SanitizeFunction;
535 LoadShadow = SanitizeFunction;
536 PoisonStack = SanitizeFunction && ClPoisonStack;
537 PoisonUndef = SanitizeFunction && ClPoisonUndef;
538 // FIXME: Consider using SpecialCaseList to specify a list of functions that
539 // must always return fully initialized values. For now, we hardcode "main".
540 CheckReturnValue = SanitizeFunction && (F.getName() == "main");
542 DEBUG(if (!InsertChecks)
543 dbgs() << "MemorySanitizer is not inserting checks into '"
544 << F.getName() << "'\n");
547 Value *updateOrigin(Value *V, IRBuilder<> &IRB) {
548 if (MS.TrackOrigins <= 1) return V;
549 return IRB.CreateCall(MS.MsanChainOriginFn, V);
552 void storeOrigin(IRBuilder<> &IRB, Value *Addr, Value *Shadow, Value *Origin,
553 unsigned Alignment, bool AsCall) {
554 if (isa<StructType>(Shadow->getType())) {
555 IRB.CreateAlignedStore(updateOrigin(Origin, IRB), getOriginPtr(Addr, IRB),
558 Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
559 // TODO(eugenis): handle non-zero constant shadow by inserting an
560 // unconditional check (can not simply fail compilation as this could
561 // be in the dead code).
562 if (isa<Constant>(ConvertedShadow)) return;
563 unsigned TypeSizeInBits =
564 MS.DL->getTypeSizeInBits(ConvertedShadow->getType());
565 unsigned SizeIndex = TypeSizeToSizeIndex(TypeSizeInBits);
566 if (AsCall && SizeIndex < kNumberOfAccessSizes) {
567 Value *Fn = MS.MaybeStoreOriginFn[SizeIndex];
568 Value *ConvertedShadow2 = IRB.CreateZExt(
569 ConvertedShadow, IRB.getIntNTy(8 * (1 << SizeIndex)));
570 IRB.CreateCall3(Fn, ConvertedShadow2,
571 IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
572 updateOrigin(Origin, IRB));
574 Value *Cmp = IRB.CreateICmpNE(
575 ConvertedShadow, getCleanShadow(ConvertedShadow), "_mscmp");
576 Instruction *CheckTerm = SplitBlockAndInsertIfThen(
577 Cmp, IRB.GetInsertPoint(), false, MS.OriginStoreWeights);
578 IRBuilder<> IRBNew(CheckTerm);
579 IRBNew.CreateAlignedStore(updateOrigin(Origin, IRBNew),
580 getOriginPtr(Addr, IRBNew), Alignment);
585 void materializeStores(bool InstrumentWithCalls) {
586 for (auto Inst : StoreList) {
587 StoreInst &SI = *dyn_cast<StoreInst>(Inst);
589 IRBuilder<> IRB(&SI);
590 Value *Val = SI.getValueOperand();
591 Value *Addr = SI.getPointerOperand();
592 Value *Shadow = SI.isAtomic() ? getCleanShadow(Val) : getShadow(Val);
593 Value *ShadowPtr = getShadowPtr(Addr, Shadow->getType(), IRB);
596 IRB.CreateAlignedStore(Shadow, ShadowPtr, SI.getAlignment());
597 DEBUG(dbgs() << " STORE: " << *NewSI << "\n");
600 if (ClCheckAccessAddress) insertShadowCheck(Addr, &SI);
602 if (SI.isAtomic()) SI.setOrdering(addReleaseOrdering(SI.getOrdering()));
604 if (MS.TrackOrigins) {
605 unsigned Alignment = std::max(kMinOriginAlignment, SI.getAlignment());
606 storeOrigin(IRB, Addr, Shadow, getOrigin(Val), Alignment,
607 InstrumentWithCalls);
612 void materializeOneCheck(Instruction *OrigIns, Value *Shadow, Value *Origin,
614 IRBuilder<> IRB(OrigIns);
615 DEBUG(dbgs() << " SHAD0 : " << *Shadow << "\n");
616 Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
617 DEBUG(dbgs() << " SHAD1 : " << *ConvertedShadow << "\n");
618 // See the comment in materializeStores().
619 if (isa<Constant>(ConvertedShadow)) return;
620 unsigned TypeSizeInBits =
621 MS.DL->getTypeSizeInBits(ConvertedShadow->getType());
622 unsigned SizeIndex = TypeSizeToSizeIndex(TypeSizeInBits);
623 if (AsCall && SizeIndex < kNumberOfAccessSizes) {
624 Value *Fn = MS.MaybeWarningFn[SizeIndex];
625 Value *ConvertedShadow2 =
626 IRB.CreateZExt(ConvertedShadow, IRB.getIntNTy(8 * (1 << SizeIndex)));
627 IRB.CreateCall2(Fn, ConvertedShadow2, MS.TrackOrigins && Origin
629 : (Value *)IRB.getInt32(0));
631 Value *Cmp = IRB.CreateICmpNE(ConvertedShadow,
632 getCleanShadow(ConvertedShadow), "_mscmp");
633 Instruction *CheckTerm = SplitBlockAndInsertIfThen(
635 /* Unreachable */ !ClKeepGoing, MS.ColdCallWeights);
637 IRB.SetInsertPoint(CheckTerm);
638 if (MS.TrackOrigins) {
639 IRB.CreateStore(Origin ? (Value *)Origin : (Value *)IRB.getInt32(0),
642 IRB.CreateCall(MS.WarningFn);
643 IRB.CreateCall(MS.EmptyAsm);
644 DEBUG(dbgs() << " CHECK: " << *Cmp << "\n");
648 void materializeChecks(bool InstrumentWithCalls) {
649 for (const auto &ShadowData : InstrumentationList) {
650 Instruction *OrigIns = ShadowData.OrigIns;
651 Value *Shadow = ShadowData.Shadow;
652 Value *Origin = ShadowData.Origin;
653 materializeOneCheck(OrigIns, Shadow, Origin, InstrumentWithCalls);
655 DEBUG(dbgs() << "DONE:\n" << F);
658 void materializeIndirectCalls() {
659 for (auto &CS : IndirectCallList) {
660 Instruction *I = CS.getInstruction();
661 BasicBlock *B = I->getParent();
663 Value *Fn0 = CS.getCalledValue();
664 Value *Fn = IRB.CreateBitCast(Fn0, MS.AnyFunctionPtrTy);
666 if (ClWrapIndirectCallsFast) {
667 // Check that call target is inside this module limits.
669 IRB.CreateBitCast(MS.MsandrModuleStart, MS.AnyFunctionPtrTy);
670 Value *End = IRB.CreateBitCast(MS.MsandrModuleEnd, MS.AnyFunctionPtrTy);
672 Value *NotInThisModule = IRB.CreateOr(IRB.CreateICmpULT(Fn, Start),
673 IRB.CreateICmpUGE(Fn, End));
676 IRB.CreatePHI(Fn0->getType(), 2, "msandr.indirect_target");
678 Instruction *CheckTerm = SplitBlockAndInsertIfThen(
679 NotInThisModule, NewFnPhi,
680 /* Unreachable */ false, MS.ColdCallWeights);
682 IRB.SetInsertPoint(CheckTerm);
683 // Slow path: call wrapper function to possibly transform the call
685 Value *NewFn = IRB.CreateBitCast(
686 IRB.CreateCall(MS.IndirectCallWrapperFn, Fn), Fn0->getType());
688 NewFnPhi->addIncoming(Fn0, B);
689 NewFnPhi->addIncoming(NewFn, dyn_cast<Instruction>(NewFn)->getParent());
690 CS.setCalledFunction(NewFnPhi);
692 Value *NewFn = IRB.CreateBitCast(
693 IRB.CreateCall(MS.IndirectCallWrapperFn, Fn), Fn0->getType());
694 CS.setCalledFunction(NewFn);
699 /// \brief Add MemorySanitizer instrumentation to a function.
700 bool runOnFunction() {
701 MS.initializeCallbacks(*F.getParent());
702 if (!MS.DL) return false;
704 // In the presence of unreachable blocks, we may see Phi nodes with
705 // incoming nodes from such blocks. Since InstVisitor skips unreachable
706 // blocks, such nodes will not have any shadow value associated with them.
707 // It's easier to remove unreachable blocks than deal with missing shadow.
708 removeUnreachableBlocks(F);
710 // Iterate all BBs in depth-first order and create shadow instructions
711 // for all instructions (where applicable).
712 // For PHI nodes we create dummy shadow PHIs which will be finalized later.
713 for (BasicBlock *BB : depth_first(&F.getEntryBlock()))
717 // Finalize PHI nodes.
718 for (PHINode *PN : ShadowPHINodes) {
719 PHINode *PNS = cast<PHINode>(getShadow(PN));
720 PHINode *PNO = MS.TrackOrigins ? cast<PHINode>(getOrigin(PN)) : nullptr;
721 size_t NumValues = PN->getNumIncomingValues();
722 for (size_t v = 0; v < NumValues; v++) {
723 PNS->addIncoming(getShadow(PN, v), PN->getIncomingBlock(v));
725 PNO->addIncoming(getOrigin(PN, v), PN->getIncomingBlock(v));
729 VAHelper->finalizeInstrumentation();
731 bool InstrumentWithCalls = ClInstrumentationWithCallThreshold >= 0 &&
732 InstrumentationList.size() + StoreList.size() >
733 (unsigned)ClInstrumentationWithCallThreshold;
735 // Delayed instrumentation of StoreInst.
736 // This may add new checks to be inserted later.
737 materializeStores(InstrumentWithCalls);
739 // Insert shadow value checks.
740 materializeChecks(InstrumentWithCalls);
742 // Wrap indirect calls.
743 materializeIndirectCalls();
748 /// \brief Compute the shadow type that corresponds to a given Value.
749 Type *getShadowTy(Value *V) {
750 return getShadowTy(V->getType());
753 /// \brief Compute the shadow type that corresponds to a given Type.
754 Type *getShadowTy(Type *OrigTy) {
755 if (!OrigTy->isSized()) {
758 // For integer type, shadow is the same as the original type.
759 // This may return weird-sized types like i1.
760 if (IntegerType *IT = dyn_cast<IntegerType>(OrigTy))
762 if (VectorType *VT = dyn_cast<VectorType>(OrigTy)) {
763 uint32_t EltSize = MS.DL->getTypeSizeInBits(VT->getElementType());
764 return VectorType::get(IntegerType::get(*MS.C, EltSize),
765 VT->getNumElements());
767 if (StructType *ST = dyn_cast<StructType>(OrigTy)) {
768 SmallVector<Type*, 4> Elements;
769 for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
770 Elements.push_back(getShadowTy(ST->getElementType(i)));
771 StructType *Res = StructType::get(*MS.C, Elements, ST->isPacked());
772 DEBUG(dbgs() << "getShadowTy: " << *ST << " ===> " << *Res << "\n");
775 uint32_t TypeSize = MS.DL->getTypeSizeInBits(OrigTy);
776 return IntegerType::get(*MS.C, TypeSize);
779 /// \brief Flatten a vector type.
780 Type *getShadowTyNoVec(Type *ty) {
781 if (VectorType *vt = dyn_cast<VectorType>(ty))
782 return IntegerType::get(*MS.C, vt->getBitWidth());
786 /// \brief Convert a shadow value to it's flattened variant.
787 Value *convertToShadowTyNoVec(Value *V, IRBuilder<> &IRB) {
788 Type *Ty = V->getType();
789 Type *NoVecTy = getShadowTyNoVec(Ty);
790 if (Ty == NoVecTy) return V;
791 return IRB.CreateBitCast(V, NoVecTy);
794 /// \brief Compute the shadow address that corresponds to a given application
797 /// Shadow = Addr & ~ShadowMask.
798 Value *getShadowPtr(Value *Addr, Type *ShadowTy,
801 IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
802 ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask));
803 return IRB.CreateIntToPtr(ShadowLong, PointerType::get(ShadowTy, 0));
806 /// \brief Compute the origin address that corresponds to a given application
809 /// OriginAddr = (ShadowAddr + OriginOffset) & ~3ULL
810 Value *getOriginPtr(Value *Addr, IRBuilder<> &IRB) {
812 IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
813 ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask));
815 IRB.CreateAdd(ShadowLong,
816 ConstantInt::get(MS.IntptrTy, MS.OriginOffset));
818 IRB.CreateAnd(Add, ConstantInt::get(MS.IntptrTy, ~3ULL));
819 return IRB.CreateIntToPtr(SecondAnd, PointerType::get(IRB.getInt32Ty(), 0));
822 /// \brief Compute the shadow address for a given function argument.
824 /// Shadow = ParamTLS+ArgOffset.
825 Value *getShadowPtrForArgument(Value *A, IRBuilder<> &IRB,
827 Value *Base = IRB.CreatePointerCast(MS.ParamTLS, MS.IntptrTy);
828 Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
829 return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A), 0),
833 /// \brief Compute the origin address for a given function argument.
834 Value *getOriginPtrForArgument(Value *A, IRBuilder<> &IRB,
836 if (!MS.TrackOrigins) return nullptr;
837 Value *Base = IRB.CreatePointerCast(MS.ParamOriginTLS, MS.IntptrTy);
838 Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
839 return IRB.CreateIntToPtr(Base, PointerType::get(MS.OriginTy, 0),
843 /// \brief Compute the shadow address for a retval.
844 Value *getShadowPtrForRetval(Value *A, IRBuilder<> &IRB) {
845 Value *Base = IRB.CreatePointerCast(MS.RetvalTLS, MS.IntptrTy);
846 return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A), 0),
850 /// \brief Compute the origin address for a retval.
851 Value *getOriginPtrForRetval(IRBuilder<> &IRB) {
852 // We keep a single origin for the entire retval. Might be too optimistic.
853 return MS.RetvalOriginTLS;
856 /// \brief Set SV to be the shadow value for V.
857 void setShadow(Value *V, Value *SV) {
858 assert(!ShadowMap.count(V) && "Values may only have one shadow");
862 /// \brief Set Origin to be the origin value for V.
863 void setOrigin(Value *V, Value *Origin) {
864 if (!MS.TrackOrigins) return;
865 assert(!OriginMap.count(V) && "Values may only have one origin");
866 DEBUG(dbgs() << "ORIGIN: " << *V << " ==> " << *Origin << "\n");
867 OriginMap[V] = Origin;
870 /// \brief Create a clean shadow value for a given value.
872 /// Clean shadow (all zeroes) means all bits of the value are defined
874 Constant *getCleanShadow(Value *V) {
875 Type *ShadowTy = getShadowTy(V);
878 return Constant::getNullValue(ShadowTy);
881 /// \brief Create a dirty shadow of a given shadow type.
882 Constant *getPoisonedShadow(Type *ShadowTy) {
884 if (isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy))
885 return Constant::getAllOnesValue(ShadowTy);
886 StructType *ST = cast<StructType>(ShadowTy);
887 SmallVector<Constant *, 4> Vals;
888 for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
889 Vals.push_back(getPoisonedShadow(ST->getElementType(i)));
890 return ConstantStruct::get(ST, Vals);
893 /// \brief Create a dirty shadow for a given value.
894 Constant *getPoisonedShadow(Value *V) {
895 Type *ShadowTy = getShadowTy(V);
898 return getPoisonedShadow(ShadowTy);
901 /// \brief Create a clean (zero) origin.
902 Value *getCleanOrigin() {
903 return Constant::getNullValue(MS.OriginTy);
906 /// \brief Get the shadow value for a given Value.
908 /// This function either returns the value set earlier with setShadow,
909 /// or extracts if from ParamTLS (for function arguments).
910 Value *getShadow(Value *V) {
911 if (Instruction *I = dyn_cast<Instruction>(V)) {
912 // For instructions the shadow is already stored in the map.
913 Value *Shadow = ShadowMap[V];
915 DEBUG(dbgs() << "No shadow: " << *V << "\n" << *(I->getParent()));
917 assert(Shadow && "No shadow for a value");
921 if (UndefValue *U = dyn_cast<UndefValue>(V)) {
922 Value *AllOnes = PoisonUndef ? getPoisonedShadow(V) : getCleanShadow(V);
923 DEBUG(dbgs() << "Undef: " << *U << " ==> " << *AllOnes << "\n");
927 if (Argument *A = dyn_cast<Argument>(V)) {
928 // For arguments we compute the shadow on demand and store it in the map.
929 Value **ShadowPtr = &ShadowMap[V];
932 Function *F = A->getParent();
933 IRBuilder<> EntryIRB(F->getEntryBlock().getFirstNonPHI());
934 unsigned ArgOffset = 0;
935 for (auto &FArg : F->args()) {
936 if (!FArg.getType()->isSized()) {
937 DEBUG(dbgs() << "Arg is not sized\n");
940 unsigned Size = FArg.hasByValAttr()
941 ? MS.DL->getTypeAllocSize(FArg.getType()->getPointerElementType())
942 : MS.DL->getTypeAllocSize(FArg.getType());
944 Value *Base = getShadowPtrForArgument(&FArg, EntryIRB, ArgOffset);
945 if (FArg.hasByValAttr()) {
946 // ByVal pointer itself has clean shadow. We copy the actual
947 // argument shadow to the underlying memory.
948 // Figure out maximal valid memcpy alignment.
949 unsigned ArgAlign = FArg.getParamAlignment();
951 Type *EltType = A->getType()->getPointerElementType();
952 ArgAlign = MS.DL->getABITypeAlignment(EltType);
954 unsigned CopyAlign = std::min(ArgAlign, kShadowTLSAlignment);
955 Value *Cpy = EntryIRB.CreateMemCpy(
956 getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB), Base, Size,
958 DEBUG(dbgs() << " ByValCpy: " << *Cpy << "\n");
960 *ShadowPtr = getCleanShadow(V);
962 *ShadowPtr = EntryIRB.CreateAlignedLoad(Base, kShadowTLSAlignment);
964 DEBUG(dbgs() << " ARG: " << FArg << " ==> " <<
965 **ShadowPtr << "\n");
966 if (MS.TrackOrigins) {
968 getOriginPtrForArgument(&FArg, EntryIRB, ArgOffset);
969 setOrigin(A, EntryIRB.CreateLoad(OriginPtr));
972 ArgOffset += DataLayout::RoundUpAlignment(Size, kShadowTLSAlignment);
974 assert(*ShadowPtr && "Could not find shadow for an argument");
977 // For everything else the shadow is zero.
978 return getCleanShadow(V);
981 /// \brief Get the shadow for i-th argument of the instruction I.
982 Value *getShadow(Instruction *I, int i) {
983 return getShadow(I->getOperand(i));
986 /// \brief Get the origin for a value.
987 Value *getOrigin(Value *V) {
988 if (!MS.TrackOrigins) return nullptr;
989 if (isa<Instruction>(V) || isa<Argument>(V)) {
990 Value *Origin = OriginMap[V];
992 DEBUG(dbgs() << "NO ORIGIN: " << *V << "\n");
993 Origin = getCleanOrigin();
997 return getCleanOrigin();
1000 /// \brief Get the origin for i-th argument of the instruction I.
1001 Value *getOrigin(Instruction *I, int i) {
1002 return getOrigin(I->getOperand(i));
1005 /// \brief Remember the place where a shadow check should be inserted.
1007 /// This location will be later instrumented with a check that will print a
1008 /// UMR warning in runtime if the shadow value is not 0.
1009 void insertShadowCheck(Value *Shadow, Value *Origin, Instruction *OrigIns) {
1011 if (!InsertChecks) return;
1013 Type *ShadowTy = Shadow->getType();
1014 assert((isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy)) &&
1015 "Can only insert checks for integer and vector shadow types");
1017 InstrumentationList.push_back(
1018 ShadowOriginAndInsertPoint(Shadow, Origin, OrigIns));
1021 /// \brief Remember the place where a shadow check should be inserted.
1023 /// This location will be later instrumented with a check that will print a
1024 /// UMR warning in runtime if the value is not fully defined.
1025 void insertShadowCheck(Value *Val, Instruction *OrigIns) {
1027 Instruction *Shadow = dyn_cast_or_null<Instruction>(getShadow(Val));
1028 if (!Shadow) return;
1029 Instruction *Origin = dyn_cast_or_null<Instruction>(getOrigin(Val));
1030 insertShadowCheck(Shadow, Origin, OrigIns);
1033 AtomicOrdering addReleaseOrdering(AtomicOrdering a) {
1042 case AcquireRelease:
1043 return AcquireRelease;
1044 case SequentiallyConsistent:
1045 return SequentiallyConsistent;
1047 llvm_unreachable("Unknown ordering");
1050 AtomicOrdering addAcquireOrdering(AtomicOrdering a) {
1059 case AcquireRelease:
1060 return AcquireRelease;
1061 case SequentiallyConsistent:
1062 return SequentiallyConsistent;
1064 llvm_unreachable("Unknown ordering");
1067 // ------------------- Visitors.
1069 /// \brief Instrument LoadInst
1071 /// Loads the corresponding shadow and (optionally) origin.
1072 /// Optionally, checks that the load address is fully defined.
1073 void visitLoadInst(LoadInst &I) {
1074 assert(I.getType()->isSized() && "Load type must have size");
1075 IRBuilder<> IRB(I.getNextNode());
1076 Type *ShadowTy = getShadowTy(&I);
1077 Value *Addr = I.getPointerOperand();
1079 Value *ShadowPtr = getShadowPtr(Addr, ShadowTy, IRB);
1081 IRB.CreateAlignedLoad(ShadowPtr, I.getAlignment(), "_msld"));
1083 setShadow(&I, getCleanShadow(&I));
1086 if (ClCheckAccessAddress)
1087 insertShadowCheck(I.getPointerOperand(), &I);
1090 I.setOrdering(addAcquireOrdering(I.getOrdering()));
1092 if (MS.TrackOrigins) {
1094 unsigned Alignment = std::max(kMinOriginAlignment, I.getAlignment());
1096 IRB.CreateAlignedLoad(getOriginPtr(Addr, IRB), Alignment));
1098 setOrigin(&I, getCleanOrigin());
1103 /// \brief Instrument StoreInst
1105 /// Stores the corresponding shadow and (optionally) origin.
1106 /// Optionally, checks that the store address is fully defined.
1107 void visitStoreInst(StoreInst &I) {
1108 StoreList.push_back(&I);
1111 void handleCASOrRMW(Instruction &I) {
1112 assert(isa<AtomicRMWInst>(I) || isa<AtomicCmpXchgInst>(I));
1114 IRBuilder<> IRB(&I);
1115 Value *Addr = I.getOperand(0);
1116 Value *ShadowPtr = getShadowPtr(Addr, I.getType(), IRB);
1118 if (ClCheckAccessAddress)
1119 insertShadowCheck(Addr, &I);
1121 // Only test the conditional argument of cmpxchg instruction.
1122 // The other argument can potentially be uninitialized, but we can not
1123 // detect this situation reliably without possible false positives.
1124 if (isa<AtomicCmpXchgInst>(I))
1125 insertShadowCheck(I.getOperand(1), &I);
1127 IRB.CreateStore(getCleanShadow(&I), ShadowPtr);
1129 setShadow(&I, getCleanShadow(&I));
1132 void visitAtomicRMWInst(AtomicRMWInst &I) {
1134 I.setOrdering(addReleaseOrdering(I.getOrdering()));
1137 void visitAtomicCmpXchgInst(AtomicCmpXchgInst &I) {
1139 I.setSuccessOrdering(addReleaseOrdering(I.getSuccessOrdering()));
1142 // Vector manipulation.
1143 void visitExtractElementInst(ExtractElementInst &I) {
1144 insertShadowCheck(I.getOperand(1), &I);
1145 IRBuilder<> IRB(&I);
1146 setShadow(&I, IRB.CreateExtractElement(getShadow(&I, 0), I.getOperand(1),
1148 setOrigin(&I, getOrigin(&I, 0));
1151 void visitInsertElementInst(InsertElementInst &I) {
1152 insertShadowCheck(I.getOperand(2), &I);
1153 IRBuilder<> IRB(&I);
1154 setShadow(&I, IRB.CreateInsertElement(getShadow(&I, 0), getShadow(&I, 1),
1155 I.getOperand(2), "_msprop"));
1156 setOriginForNaryOp(I);
1159 void visitShuffleVectorInst(ShuffleVectorInst &I) {
1160 insertShadowCheck(I.getOperand(2), &I);
1161 IRBuilder<> IRB(&I);
1162 setShadow(&I, IRB.CreateShuffleVector(getShadow(&I, 0), getShadow(&I, 1),
1163 I.getOperand(2), "_msprop"));
1164 setOriginForNaryOp(I);
1168 void visitSExtInst(SExtInst &I) {
1169 IRBuilder<> IRB(&I);
1170 setShadow(&I, IRB.CreateSExt(getShadow(&I, 0), I.getType(), "_msprop"));
1171 setOrigin(&I, getOrigin(&I, 0));
1174 void visitZExtInst(ZExtInst &I) {
1175 IRBuilder<> IRB(&I);
1176 setShadow(&I, IRB.CreateZExt(getShadow(&I, 0), I.getType(), "_msprop"));
1177 setOrigin(&I, getOrigin(&I, 0));
1180 void visitTruncInst(TruncInst &I) {
1181 IRBuilder<> IRB(&I);
1182 setShadow(&I, IRB.CreateTrunc(getShadow(&I, 0), I.getType(), "_msprop"));
1183 setOrigin(&I, getOrigin(&I, 0));
1186 void visitBitCastInst(BitCastInst &I) {
1187 IRBuilder<> IRB(&I);
1188 setShadow(&I, IRB.CreateBitCast(getShadow(&I, 0), getShadowTy(&I)));
1189 setOrigin(&I, getOrigin(&I, 0));
1192 void visitPtrToIntInst(PtrToIntInst &I) {
1193 IRBuilder<> IRB(&I);
1194 setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I), false,
1195 "_msprop_ptrtoint"));
1196 setOrigin(&I, getOrigin(&I, 0));
1199 void visitIntToPtrInst(IntToPtrInst &I) {
1200 IRBuilder<> IRB(&I);
1201 setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I), false,
1202 "_msprop_inttoptr"));
1203 setOrigin(&I, getOrigin(&I, 0));
1206 void visitFPToSIInst(CastInst& I) { handleShadowOr(I); }
1207 void visitFPToUIInst(CastInst& I) { handleShadowOr(I); }
1208 void visitSIToFPInst(CastInst& I) { handleShadowOr(I); }
1209 void visitUIToFPInst(CastInst& I) { handleShadowOr(I); }
1210 void visitFPExtInst(CastInst& I) { handleShadowOr(I); }
1211 void visitFPTruncInst(CastInst& I) { handleShadowOr(I); }
1213 /// \brief Propagate shadow for bitwise AND.
1215 /// This code is exact, i.e. if, for example, a bit in the left argument
1216 /// is defined and 0, then neither the value not definedness of the
1217 /// corresponding bit in B don't affect the resulting shadow.
1218 void visitAnd(BinaryOperator &I) {
1219 IRBuilder<> IRB(&I);
1220 // "And" of 0 and a poisoned value results in unpoisoned value.
1221 // 1&1 => 1; 0&1 => 0; p&1 => p;
1222 // 1&0 => 0; 0&0 => 0; p&0 => 0;
1223 // 1&p => p; 0&p => 0; p&p => p;
1224 // S = (S1 & S2) | (V1 & S2) | (S1 & V2)
1225 Value *S1 = getShadow(&I, 0);
1226 Value *S2 = getShadow(&I, 1);
1227 Value *V1 = I.getOperand(0);
1228 Value *V2 = I.getOperand(1);
1229 if (V1->getType() != S1->getType()) {
1230 V1 = IRB.CreateIntCast(V1, S1->getType(), false);
1231 V2 = IRB.CreateIntCast(V2, S2->getType(), false);
1233 Value *S1S2 = IRB.CreateAnd(S1, S2);
1234 Value *V1S2 = IRB.CreateAnd(V1, S2);
1235 Value *S1V2 = IRB.CreateAnd(S1, V2);
1236 setShadow(&I, IRB.CreateOr(S1S2, IRB.CreateOr(V1S2, S1V2)));
1237 setOriginForNaryOp(I);
1240 void visitOr(BinaryOperator &I) {
1241 IRBuilder<> IRB(&I);
1242 // "Or" of 1 and a poisoned value results in unpoisoned value.
1243 // 1|1 => 1; 0|1 => 1; p|1 => 1;
1244 // 1|0 => 1; 0|0 => 0; p|0 => p;
1245 // 1|p => 1; 0|p => p; p|p => p;
1246 // S = (S1 & S2) | (~V1 & S2) | (S1 & ~V2)
1247 Value *S1 = getShadow(&I, 0);
1248 Value *S2 = getShadow(&I, 1);
1249 Value *V1 = IRB.CreateNot(I.getOperand(0));
1250 Value *V2 = IRB.CreateNot(I.getOperand(1));
1251 if (V1->getType() != S1->getType()) {
1252 V1 = IRB.CreateIntCast(V1, S1->getType(), false);
1253 V2 = IRB.CreateIntCast(V2, S2->getType(), false);
1255 Value *S1S2 = IRB.CreateAnd(S1, S2);
1256 Value *V1S2 = IRB.CreateAnd(V1, S2);
1257 Value *S1V2 = IRB.CreateAnd(S1, V2);
1258 setShadow(&I, IRB.CreateOr(S1S2, IRB.CreateOr(V1S2, S1V2)));
1259 setOriginForNaryOp(I);
1262 /// \brief Default propagation of shadow and/or origin.
1264 /// This class implements the general case of shadow propagation, used in all
1265 /// cases where we don't know and/or don't care about what the operation
1266 /// actually does. It converts all input shadow values to a common type
1267 /// (extending or truncating as necessary), and bitwise OR's them.
1269 /// This is much cheaper than inserting checks (i.e. requiring inputs to be
1270 /// fully initialized), and less prone to false positives.
1272 /// This class also implements the general case of origin propagation. For a
1273 /// Nary operation, result origin is set to the origin of an argument that is
1274 /// not entirely initialized. If there is more than one such arguments, the
1275 /// rightmost of them is picked. It does not matter which one is picked if all
1276 /// arguments are initialized.
1277 template <bool CombineShadow>
1282 MemorySanitizerVisitor *MSV;
1285 Combiner(MemorySanitizerVisitor *MSV, IRBuilder<> &IRB) :
1286 Shadow(nullptr), Origin(nullptr), IRB(IRB), MSV(MSV) {}
1288 /// \brief Add a pair of shadow and origin values to the mix.
1289 Combiner &Add(Value *OpShadow, Value *OpOrigin) {
1290 if (CombineShadow) {
1295 OpShadow = MSV->CreateShadowCast(IRB, OpShadow, Shadow->getType());
1296 Shadow = IRB.CreateOr(Shadow, OpShadow, "_msprop");
1300 if (MSV->MS.TrackOrigins) {
1305 Constant *ConstOrigin = dyn_cast<Constant>(OpOrigin);
1306 // No point in adding something that might result in 0 origin value.
1307 if (!ConstOrigin || !ConstOrigin->isNullValue()) {
1308 Value *FlatShadow = MSV->convertToShadowTyNoVec(OpShadow, IRB);
1310 IRB.CreateICmpNE(FlatShadow, MSV->getCleanShadow(FlatShadow));
1311 Origin = IRB.CreateSelect(Cond, OpOrigin, Origin);
1318 /// \brief Add an application value to the mix.
1319 Combiner &Add(Value *V) {
1320 Value *OpShadow = MSV->getShadow(V);
1321 Value *OpOrigin = MSV->MS.TrackOrigins ? MSV->getOrigin(V) : nullptr;
1322 return Add(OpShadow, OpOrigin);
1325 /// \brief Set the current combined values as the given instruction's shadow
1327 void Done(Instruction *I) {
1328 if (CombineShadow) {
1330 Shadow = MSV->CreateShadowCast(IRB, Shadow, MSV->getShadowTy(I));
1331 MSV->setShadow(I, Shadow);
1333 if (MSV->MS.TrackOrigins) {
1335 MSV->setOrigin(I, Origin);
1340 typedef Combiner<true> ShadowAndOriginCombiner;
1341 typedef Combiner<false> OriginCombiner;
1343 /// \brief Propagate origin for arbitrary operation.
1344 void setOriginForNaryOp(Instruction &I) {
1345 if (!MS.TrackOrigins) return;
1346 IRBuilder<> IRB(&I);
1347 OriginCombiner OC(this, IRB);
1348 for (Instruction::op_iterator OI = I.op_begin(); OI != I.op_end(); ++OI)
1353 size_t VectorOrPrimitiveTypeSizeInBits(Type *Ty) {
1354 assert(!(Ty->isVectorTy() && Ty->getScalarType()->isPointerTy()) &&
1355 "Vector of pointers is not a valid shadow type");
1356 return Ty->isVectorTy() ?
1357 Ty->getVectorNumElements() * Ty->getScalarSizeInBits() :
1358 Ty->getPrimitiveSizeInBits();
1361 /// \brief Cast between two shadow types, extending or truncating as
1363 Value *CreateShadowCast(IRBuilder<> &IRB, Value *V, Type *dstTy,
1364 bool Signed = false) {
1365 Type *srcTy = V->getType();
1366 if (dstTy->isIntegerTy() && srcTy->isIntegerTy())
1367 return IRB.CreateIntCast(V, dstTy, Signed);
1368 if (dstTy->isVectorTy() && srcTy->isVectorTy() &&
1369 dstTy->getVectorNumElements() == srcTy->getVectorNumElements())
1370 return IRB.CreateIntCast(V, dstTy, Signed);
1371 size_t srcSizeInBits = VectorOrPrimitiveTypeSizeInBits(srcTy);
1372 size_t dstSizeInBits = VectorOrPrimitiveTypeSizeInBits(dstTy);
1373 Value *V1 = IRB.CreateBitCast(V, Type::getIntNTy(*MS.C, srcSizeInBits));
1375 IRB.CreateIntCast(V1, Type::getIntNTy(*MS.C, dstSizeInBits), Signed);
1376 return IRB.CreateBitCast(V2, dstTy);
1377 // TODO: handle struct types.
1380 /// \brief Cast an application value to the type of its own shadow.
1381 Value *CreateAppToShadowCast(IRBuilder<> &IRB, Value *V) {
1382 Type *ShadowTy = getShadowTy(V);
1383 if (V->getType() == ShadowTy)
1385 if (V->getType()->isPtrOrPtrVectorTy())
1386 return IRB.CreatePtrToInt(V, ShadowTy);
1388 return IRB.CreateBitCast(V, ShadowTy);
1391 /// \brief Propagate shadow for arbitrary operation.
1392 void handleShadowOr(Instruction &I) {
1393 IRBuilder<> IRB(&I);
1394 ShadowAndOriginCombiner SC(this, IRB);
1395 for (Instruction::op_iterator OI = I.op_begin(); OI != I.op_end(); ++OI)
1400 // \brief Handle multiplication by constant.
1402 // Handle a special case of multiplication by constant that may have one or
1403 // more zeros in the lower bits. This makes corresponding number of lower bits
1404 // of the result zero as well. We model it by shifting the other operand
1405 // shadow left by the required number of bits. Effectively, we transform
1406 // (X * (A * 2**B)) to ((X << B) * A) and instrument (X << B) as (Sx << B).
1407 // We use multiplication by 2**N instead of shift to cover the case of
1408 // multiplication by 0, which may occur in some elements of a vector operand.
1409 void handleMulByConstant(BinaryOperator &I, Constant *ConstArg,
1411 Constant *ShadowMul;
1412 Type *Ty = ConstArg->getType();
1413 if (Ty->isVectorTy()) {
1414 unsigned NumElements = Ty->getVectorNumElements();
1415 Type *EltTy = Ty->getSequentialElementType();
1416 SmallVector<Constant *, 16> Elements;
1417 for (unsigned Idx = 0; Idx < NumElements; ++Idx) {
1419 dyn_cast<ConstantInt>(ConstArg->getAggregateElement(Idx));
1420 APInt V = Elt->getValue();
1421 APInt V2 = APInt(V.getBitWidth(), 1) << V.countTrailingZeros();
1422 Elements.push_back(ConstantInt::get(EltTy, V2));
1424 ShadowMul = ConstantVector::get(Elements);
1426 ConstantInt *Elt = dyn_cast<ConstantInt>(ConstArg);
1427 APInt V = Elt->getValue();
1428 APInt V2 = APInt(V.getBitWidth(), 1) << V.countTrailingZeros();
1429 ShadowMul = ConstantInt::get(Elt->getType(), V2);
1432 IRBuilder<> IRB(&I);
1434 IRB.CreateMul(getShadow(OtherArg), ShadowMul, "msprop_mul_cst"));
1435 setOrigin(&I, getOrigin(OtherArg));
1438 void visitMul(BinaryOperator &I) {
1439 Constant *constOp0 = dyn_cast<Constant>(I.getOperand(0));
1440 Constant *constOp1 = dyn_cast<Constant>(I.getOperand(1));
1441 if (constOp0 && !constOp1)
1442 handleMulByConstant(I, constOp0, I.getOperand(1));
1443 else if (constOp1 && !constOp0)
1444 handleMulByConstant(I, constOp1, I.getOperand(0));
1449 void visitFAdd(BinaryOperator &I) { handleShadowOr(I); }
1450 void visitFSub(BinaryOperator &I) { handleShadowOr(I); }
1451 void visitFMul(BinaryOperator &I) { handleShadowOr(I); }
1452 void visitAdd(BinaryOperator &I) { handleShadowOr(I); }
1453 void visitSub(BinaryOperator &I) { handleShadowOr(I); }
1454 void visitXor(BinaryOperator &I) { handleShadowOr(I); }
1456 void handleDiv(Instruction &I) {
1457 IRBuilder<> IRB(&I);
1458 // Strict on the second argument.
1459 insertShadowCheck(I.getOperand(1), &I);
1460 setShadow(&I, getShadow(&I, 0));
1461 setOrigin(&I, getOrigin(&I, 0));
1464 void visitUDiv(BinaryOperator &I) { handleDiv(I); }
1465 void visitSDiv(BinaryOperator &I) { handleDiv(I); }
1466 void visitFDiv(BinaryOperator &I) { handleDiv(I); }
1467 void visitURem(BinaryOperator &I) { handleDiv(I); }
1468 void visitSRem(BinaryOperator &I) { handleDiv(I); }
1469 void visitFRem(BinaryOperator &I) { handleDiv(I); }
1471 /// \brief Instrument == and != comparisons.
1473 /// Sometimes the comparison result is known even if some of the bits of the
1474 /// arguments are not.
1475 void handleEqualityComparison(ICmpInst &I) {
1476 IRBuilder<> IRB(&I);
1477 Value *A = I.getOperand(0);
1478 Value *B = I.getOperand(1);
1479 Value *Sa = getShadow(A);
1480 Value *Sb = getShadow(B);
1482 // Get rid of pointers and vectors of pointers.
1483 // For ints (and vectors of ints), types of A and Sa match,
1484 // and this is a no-op.
1485 A = IRB.CreatePointerCast(A, Sa->getType());
1486 B = IRB.CreatePointerCast(B, Sb->getType());
1488 // A == B <==> (C = A^B) == 0
1489 // A != B <==> (C = A^B) != 0
1491 Value *C = IRB.CreateXor(A, B);
1492 Value *Sc = IRB.CreateOr(Sa, Sb);
1493 // Now dealing with i = (C == 0) comparison (or C != 0, does not matter now)
1494 // Result is defined if one of the following is true
1495 // * there is a defined 1 bit in C
1496 // * C is fully defined
1497 // Si = !(C & ~Sc) && Sc
1498 Value *Zero = Constant::getNullValue(Sc->getType());
1499 Value *MinusOne = Constant::getAllOnesValue(Sc->getType());
1501 IRB.CreateAnd(IRB.CreateICmpNE(Sc, Zero),
1503 IRB.CreateAnd(IRB.CreateXor(Sc, MinusOne), C), Zero));
1504 Si->setName("_msprop_icmp");
1506 setOriginForNaryOp(I);
1509 /// \brief Build the lowest possible value of V, taking into account V's
1510 /// uninitialized bits.
1511 Value *getLowestPossibleValue(IRBuilder<> &IRB, Value *A, Value *Sa,
1514 // Split shadow into sign bit and other bits.
1515 Value *SaOtherBits = IRB.CreateLShr(IRB.CreateShl(Sa, 1), 1);
1516 Value *SaSignBit = IRB.CreateXor(Sa, SaOtherBits);
1517 // Maximise the undefined shadow bit, minimize other undefined bits.
1519 IRB.CreateOr(IRB.CreateAnd(A, IRB.CreateNot(SaOtherBits)), SaSignBit);
1521 // Minimize undefined bits.
1522 return IRB.CreateAnd(A, IRB.CreateNot(Sa));
1526 /// \brief Build the highest possible value of V, taking into account V's
1527 /// uninitialized bits.
1528 Value *getHighestPossibleValue(IRBuilder<> &IRB, Value *A, Value *Sa,
1531 // Split shadow into sign bit and other bits.
1532 Value *SaOtherBits = IRB.CreateLShr(IRB.CreateShl(Sa, 1), 1);
1533 Value *SaSignBit = IRB.CreateXor(Sa, SaOtherBits);
1534 // Minimise the undefined shadow bit, maximise other undefined bits.
1536 IRB.CreateOr(IRB.CreateAnd(A, IRB.CreateNot(SaSignBit)), SaOtherBits);
1538 // Maximize undefined bits.
1539 return IRB.CreateOr(A, Sa);
1543 /// \brief Instrument relational comparisons.
1545 /// This function does exact shadow propagation for all relational
1546 /// comparisons of integers, pointers and vectors of those.
1547 /// FIXME: output seems suboptimal when one of the operands is a constant
1548 void handleRelationalComparisonExact(ICmpInst &I) {
1549 IRBuilder<> IRB(&I);
1550 Value *A = I.getOperand(0);
1551 Value *B = I.getOperand(1);
1552 Value *Sa = getShadow(A);
1553 Value *Sb = getShadow(B);
1555 // Get rid of pointers and vectors of pointers.
1556 // For ints (and vectors of ints), types of A and Sa match,
1557 // and this is a no-op.
1558 A = IRB.CreatePointerCast(A, Sa->getType());
1559 B = IRB.CreatePointerCast(B, Sb->getType());
1561 // Let [a0, a1] be the interval of possible values of A, taking into account
1562 // its undefined bits. Let [b0, b1] be the interval of possible values of B.
1563 // Then (A cmp B) is defined iff (a0 cmp b1) == (a1 cmp b0).
1564 bool IsSigned = I.isSigned();
1565 Value *S1 = IRB.CreateICmp(I.getPredicate(),
1566 getLowestPossibleValue(IRB, A, Sa, IsSigned),
1567 getHighestPossibleValue(IRB, B, Sb, IsSigned));
1568 Value *S2 = IRB.CreateICmp(I.getPredicate(),
1569 getHighestPossibleValue(IRB, A, Sa, IsSigned),
1570 getLowestPossibleValue(IRB, B, Sb, IsSigned));
1571 Value *Si = IRB.CreateXor(S1, S2);
1573 setOriginForNaryOp(I);
1576 /// \brief Instrument signed relational comparisons.
1578 /// Handle (x<0) and (x>=0) comparisons (essentially, sign bit tests) by
1579 /// propagating the highest bit of the shadow. Everything else is delegated
1580 /// to handleShadowOr().
1581 void handleSignedRelationalComparison(ICmpInst &I) {
1582 Constant *constOp0 = dyn_cast<Constant>(I.getOperand(0));
1583 Constant *constOp1 = dyn_cast<Constant>(I.getOperand(1));
1584 Value* op = nullptr;
1585 CmpInst::Predicate pre = I.getPredicate();
1586 if (constOp0 && constOp0->isNullValue() &&
1587 (pre == CmpInst::ICMP_SGT || pre == CmpInst::ICMP_SLE)) {
1588 op = I.getOperand(1);
1589 } else if (constOp1 && constOp1->isNullValue() &&
1590 (pre == CmpInst::ICMP_SLT || pre == CmpInst::ICMP_SGE)) {
1591 op = I.getOperand(0);
1594 IRBuilder<> IRB(&I);
1596 IRB.CreateICmpSLT(getShadow(op), getCleanShadow(op), "_msprop_icmpslt");
1597 setShadow(&I, Shadow);
1598 setOrigin(&I, getOrigin(op));
1604 void visitICmpInst(ICmpInst &I) {
1605 if (!ClHandleICmp) {
1609 if (I.isEquality()) {
1610 handleEqualityComparison(I);
1614 assert(I.isRelational());
1615 if (ClHandleICmpExact) {
1616 handleRelationalComparisonExact(I);
1620 handleSignedRelationalComparison(I);
1624 assert(I.isUnsigned());
1625 if ((isa<Constant>(I.getOperand(0)) || isa<Constant>(I.getOperand(1)))) {
1626 handleRelationalComparisonExact(I);
1633 void visitFCmpInst(FCmpInst &I) {
1637 void handleShift(BinaryOperator &I) {
1638 IRBuilder<> IRB(&I);
1639 // If any of the S2 bits are poisoned, the whole thing is poisoned.
1640 // Otherwise perform the same shift on S1.
1641 Value *S1 = getShadow(&I, 0);
1642 Value *S2 = getShadow(&I, 1);
1643 Value *S2Conv = IRB.CreateSExt(IRB.CreateICmpNE(S2, getCleanShadow(S2)),
1645 Value *V2 = I.getOperand(1);
1646 Value *Shift = IRB.CreateBinOp(I.getOpcode(), S1, V2);
1647 setShadow(&I, IRB.CreateOr(Shift, S2Conv));
1648 setOriginForNaryOp(I);
1651 void visitShl(BinaryOperator &I) { handleShift(I); }
1652 void visitAShr(BinaryOperator &I) { handleShift(I); }
1653 void visitLShr(BinaryOperator &I) { handleShift(I); }
1655 /// \brief Instrument llvm.memmove
1657 /// At this point we don't know if llvm.memmove will be inlined or not.
1658 /// If we don't instrument it and it gets inlined,
1659 /// our interceptor will not kick in and we will lose the memmove.
1660 /// If we instrument the call here, but it does not get inlined,
1661 /// we will memove the shadow twice: which is bad in case
1662 /// of overlapping regions. So, we simply lower the intrinsic to a call.
1664 /// Similar situation exists for memcpy and memset.
1665 void visitMemMoveInst(MemMoveInst &I) {
1666 IRBuilder<> IRB(&I);
1669 IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
1670 IRB.CreatePointerCast(I.getArgOperand(1), IRB.getInt8PtrTy()),
1671 IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false));
1672 I.eraseFromParent();
1675 // Similar to memmove: avoid copying shadow twice.
1676 // This is somewhat unfortunate as it may slowdown small constant memcpys.
1677 // FIXME: consider doing manual inline for small constant sizes and proper
1679 void visitMemCpyInst(MemCpyInst &I) {
1680 IRBuilder<> IRB(&I);
1683 IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
1684 IRB.CreatePointerCast(I.getArgOperand(1), IRB.getInt8PtrTy()),
1685 IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false));
1686 I.eraseFromParent();
1690 void visitMemSetInst(MemSetInst &I) {
1691 IRBuilder<> IRB(&I);
1694 IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
1695 IRB.CreateIntCast(I.getArgOperand(1), IRB.getInt32Ty(), false),
1696 IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false));
1697 I.eraseFromParent();
1700 void visitVAStartInst(VAStartInst &I) {
1701 VAHelper->visitVAStartInst(I);
1704 void visitVACopyInst(VACopyInst &I) {
1705 VAHelper->visitVACopyInst(I);
1708 enum IntrinsicKind {
1709 IK_DoesNotAccessMemory,
1714 static IntrinsicKind getIntrinsicKind(Intrinsic::ID iid) {
1715 const int DoesNotAccessMemory = IK_DoesNotAccessMemory;
1716 const int OnlyReadsArgumentPointees = IK_OnlyReadsMemory;
1717 const int OnlyReadsMemory = IK_OnlyReadsMemory;
1718 const int OnlyAccessesArgumentPointees = IK_WritesMemory;
1719 const int UnknownModRefBehavior = IK_WritesMemory;
1720 #define GET_INTRINSIC_MODREF_BEHAVIOR
1721 #define ModRefBehavior IntrinsicKind
1722 #include "llvm/IR/Intrinsics.gen"
1723 #undef ModRefBehavior
1724 #undef GET_INTRINSIC_MODREF_BEHAVIOR
1727 /// \brief Handle vector store-like intrinsics.
1729 /// Instrument intrinsics that look like a simple SIMD store: writes memory,
1730 /// has 1 pointer argument and 1 vector argument, returns void.
1731 bool handleVectorStoreIntrinsic(IntrinsicInst &I) {
1732 IRBuilder<> IRB(&I);
1733 Value* Addr = I.getArgOperand(0);
1734 Value *Shadow = getShadow(&I, 1);
1735 Value *ShadowPtr = getShadowPtr(Addr, Shadow->getType(), IRB);
1737 // We don't know the pointer alignment (could be unaligned SSE store!).
1738 // Have to assume to worst case.
1739 IRB.CreateAlignedStore(Shadow, ShadowPtr, 1);
1741 if (ClCheckAccessAddress)
1742 insertShadowCheck(Addr, &I);
1744 // FIXME: use ClStoreCleanOrigin
1745 // FIXME: factor out common code from materializeStores
1746 if (MS.TrackOrigins)
1747 IRB.CreateStore(getOrigin(&I, 1), getOriginPtr(Addr, IRB));
1751 /// \brief Handle vector load-like intrinsics.
1753 /// Instrument intrinsics that look like a simple SIMD load: reads memory,
1754 /// has 1 pointer argument, returns a vector.
1755 bool handleVectorLoadIntrinsic(IntrinsicInst &I) {
1756 IRBuilder<> IRB(&I);
1757 Value *Addr = I.getArgOperand(0);
1759 Type *ShadowTy = getShadowTy(&I);
1761 Value *ShadowPtr = getShadowPtr(Addr, ShadowTy, IRB);
1762 // We don't know the pointer alignment (could be unaligned SSE load!).
1763 // Have to assume to worst case.
1764 setShadow(&I, IRB.CreateAlignedLoad(ShadowPtr, 1, "_msld"));
1766 setShadow(&I, getCleanShadow(&I));
1769 if (ClCheckAccessAddress)
1770 insertShadowCheck(Addr, &I);
1772 if (MS.TrackOrigins) {
1774 setOrigin(&I, IRB.CreateLoad(getOriginPtr(Addr, IRB)));
1776 setOrigin(&I, getCleanOrigin());
1781 /// \brief Handle (SIMD arithmetic)-like intrinsics.
1783 /// Instrument intrinsics with any number of arguments of the same type,
1784 /// equal to the return type. The type should be simple (no aggregates or
1785 /// pointers; vectors are fine).
1786 /// Caller guarantees that this intrinsic does not access memory.
1787 bool maybeHandleSimpleNomemIntrinsic(IntrinsicInst &I) {
1788 Type *RetTy = I.getType();
1789 if (!(RetTy->isIntOrIntVectorTy() ||
1790 RetTy->isFPOrFPVectorTy() ||
1791 RetTy->isX86_MMXTy()))
1794 unsigned NumArgOperands = I.getNumArgOperands();
1796 for (unsigned i = 0; i < NumArgOperands; ++i) {
1797 Type *Ty = I.getArgOperand(i)->getType();
1802 IRBuilder<> IRB(&I);
1803 ShadowAndOriginCombiner SC(this, IRB);
1804 for (unsigned i = 0; i < NumArgOperands; ++i)
1805 SC.Add(I.getArgOperand(i));
1811 /// \brief Heuristically instrument unknown intrinsics.
1813 /// The main purpose of this code is to do something reasonable with all
1814 /// random intrinsics we might encounter, most importantly - SIMD intrinsics.
1815 /// We recognize several classes of intrinsics by their argument types and
1816 /// ModRefBehaviour and apply special intrumentation when we are reasonably
1817 /// sure that we know what the intrinsic does.
1819 /// We special-case intrinsics where this approach fails. See llvm.bswap
1820 /// handling as an example of that.
1821 bool handleUnknownIntrinsic(IntrinsicInst &I) {
1822 unsigned NumArgOperands = I.getNumArgOperands();
1823 if (NumArgOperands == 0)
1826 Intrinsic::ID iid = I.getIntrinsicID();
1827 IntrinsicKind IK = getIntrinsicKind(iid);
1828 bool OnlyReadsMemory = IK == IK_OnlyReadsMemory;
1829 bool WritesMemory = IK == IK_WritesMemory;
1830 assert(!(OnlyReadsMemory && WritesMemory));
1832 if (NumArgOperands == 2 &&
1833 I.getArgOperand(0)->getType()->isPointerTy() &&
1834 I.getArgOperand(1)->getType()->isVectorTy() &&
1835 I.getType()->isVoidTy() &&
1837 // This looks like a vector store.
1838 return handleVectorStoreIntrinsic(I);
1841 if (NumArgOperands == 1 &&
1842 I.getArgOperand(0)->getType()->isPointerTy() &&
1843 I.getType()->isVectorTy() &&
1845 // This looks like a vector load.
1846 return handleVectorLoadIntrinsic(I);
1849 if (!OnlyReadsMemory && !WritesMemory)
1850 if (maybeHandleSimpleNomemIntrinsic(I))
1853 // FIXME: detect and handle SSE maskstore/maskload
1857 void handleBswap(IntrinsicInst &I) {
1858 IRBuilder<> IRB(&I);
1859 Value *Op = I.getArgOperand(0);
1860 Type *OpType = Op->getType();
1861 Function *BswapFunc = Intrinsic::getDeclaration(
1862 F.getParent(), Intrinsic::bswap, ArrayRef<Type*>(&OpType, 1));
1863 setShadow(&I, IRB.CreateCall(BswapFunc, getShadow(Op)));
1864 setOrigin(&I, getOrigin(Op));
1867 // \brief Instrument vector convert instrinsic.
1869 // This function instruments intrinsics like cvtsi2ss:
1870 // %Out = int_xxx_cvtyyy(%ConvertOp)
1872 // %Out = int_xxx_cvtyyy(%CopyOp, %ConvertOp)
1873 // Intrinsic converts \p NumUsedElements elements of \p ConvertOp to the same
1874 // number \p Out elements, and (if has 2 arguments) copies the rest of the
1875 // elements from \p CopyOp.
1876 // In most cases conversion involves floating-point value which may trigger a
1877 // hardware exception when not fully initialized. For this reason we require
1878 // \p ConvertOp[0:NumUsedElements] to be fully initialized and trap otherwise.
1879 // We copy the shadow of \p CopyOp[NumUsedElements:] to \p
1880 // Out[NumUsedElements:]. This means that intrinsics without \p CopyOp always
1881 // return a fully initialized value.
1882 void handleVectorConvertIntrinsic(IntrinsicInst &I, int NumUsedElements) {
1883 IRBuilder<> IRB(&I);
1884 Value *CopyOp, *ConvertOp;
1886 switch (I.getNumArgOperands()) {
1888 CopyOp = I.getArgOperand(0);
1889 ConvertOp = I.getArgOperand(1);
1892 ConvertOp = I.getArgOperand(0);
1896 llvm_unreachable("Cvt intrinsic with unsupported number of arguments.");
1899 // The first *NumUsedElements* elements of ConvertOp are converted to the
1900 // same number of output elements. The rest of the output is copied from
1901 // CopyOp, or (if not available) filled with zeroes.
1902 // Combine shadow for elements of ConvertOp that are used in this operation,
1903 // and insert a check.
1904 // FIXME: consider propagating shadow of ConvertOp, at least in the case of
1905 // int->any conversion.
1906 Value *ConvertShadow = getShadow(ConvertOp);
1907 Value *AggShadow = nullptr;
1908 if (ConvertOp->getType()->isVectorTy()) {
1909 AggShadow = IRB.CreateExtractElement(
1910 ConvertShadow, ConstantInt::get(IRB.getInt32Ty(), 0));
1911 for (int i = 1; i < NumUsedElements; ++i) {
1912 Value *MoreShadow = IRB.CreateExtractElement(
1913 ConvertShadow, ConstantInt::get(IRB.getInt32Ty(), i));
1914 AggShadow = IRB.CreateOr(AggShadow, MoreShadow);
1917 AggShadow = ConvertShadow;
1919 assert(AggShadow->getType()->isIntegerTy());
1920 insertShadowCheck(AggShadow, getOrigin(ConvertOp), &I);
1922 // Build result shadow by zero-filling parts of CopyOp shadow that come from
1925 assert(CopyOp->getType() == I.getType());
1926 assert(CopyOp->getType()->isVectorTy());
1927 Value *ResultShadow = getShadow(CopyOp);
1928 Type *EltTy = ResultShadow->getType()->getVectorElementType();
1929 for (int i = 0; i < NumUsedElements; ++i) {
1930 ResultShadow = IRB.CreateInsertElement(
1931 ResultShadow, ConstantInt::getNullValue(EltTy),
1932 ConstantInt::get(IRB.getInt32Ty(), i));
1934 setShadow(&I, ResultShadow);
1935 setOrigin(&I, getOrigin(CopyOp));
1937 setShadow(&I, getCleanShadow(&I));
1941 // Given a scalar or vector, extract lower 64 bits (or less), and return all
1942 // zeroes if it is zero, and all ones otherwise.
1943 Value *Lower64ShadowExtend(IRBuilder<> &IRB, Value *S, Type *T) {
1944 if (S->getType()->isVectorTy())
1945 S = CreateShadowCast(IRB, S, IRB.getInt64Ty(), /* Signed */ true);
1946 assert(S->getType()->getPrimitiveSizeInBits() <= 64);
1947 Value *S2 = IRB.CreateICmpNE(S, getCleanShadow(S));
1948 return CreateShadowCast(IRB, S2, T, /* Signed */ true);
1951 Value *VariableShadowExtend(IRBuilder<> &IRB, Value *S) {
1952 Type *T = S->getType();
1953 assert(T->isVectorTy());
1954 Value *S2 = IRB.CreateICmpNE(S, getCleanShadow(S));
1955 return IRB.CreateSExt(S2, T);
1958 // \brief Instrument vector shift instrinsic.
1960 // This function instruments intrinsics like int_x86_avx2_psll_w.
1961 // Intrinsic shifts %In by %ShiftSize bits.
1962 // %ShiftSize may be a vector. In that case the lower 64 bits determine shift
1963 // size, and the rest is ignored. Behavior is defined even if shift size is
1964 // greater than register (or field) width.
1965 void handleVectorShiftIntrinsic(IntrinsicInst &I, bool Variable) {
1966 assert(I.getNumArgOperands() == 2);
1967 IRBuilder<> IRB(&I);
1968 // If any of the S2 bits are poisoned, the whole thing is poisoned.
1969 // Otherwise perform the same shift on S1.
1970 Value *S1 = getShadow(&I, 0);
1971 Value *S2 = getShadow(&I, 1);
1972 Value *S2Conv = Variable ? VariableShadowExtend(IRB, S2)
1973 : Lower64ShadowExtend(IRB, S2, getShadowTy(&I));
1974 Value *V1 = I.getOperand(0);
1975 Value *V2 = I.getOperand(1);
1976 Value *Shift = IRB.CreateCall2(I.getCalledValue(),
1977 IRB.CreateBitCast(S1, V1->getType()), V2);
1978 Shift = IRB.CreateBitCast(Shift, getShadowTy(&I));
1979 setShadow(&I, IRB.CreateOr(Shift, S2Conv));
1980 setOriginForNaryOp(I);
1983 // \brief Get an X86_MMX-sized vector type.
1984 Type *getMMXVectorTy(unsigned EltSizeInBits) {
1985 const unsigned X86_MMXSizeInBits = 64;
1986 return VectorType::get(IntegerType::get(*MS.C, EltSizeInBits),
1987 X86_MMXSizeInBits / EltSizeInBits);
1990 // \brief Returns a signed counterpart for an (un)signed-saturate-and-pack
1992 Intrinsic::ID getSignedPackIntrinsic(Intrinsic::ID id) {
1994 case llvm::Intrinsic::x86_sse2_packsswb_128:
1995 case llvm::Intrinsic::x86_sse2_packuswb_128:
1996 return llvm::Intrinsic::x86_sse2_packsswb_128;
1998 case llvm::Intrinsic::x86_sse2_packssdw_128:
1999 case llvm::Intrinsic::x86_sse41_packusdw:
2000 return llvm::Intrinsic::x86_sse2_packssdw_128;
2002 case llvm::Intrinsic::x86_avx2_packsswb:
2003 case llvm::Intrinsic::x86_avx2_packuswb:
2004 return llvm::Intrinsic::x86_avx2_packsswb;
2006 case llvm::Intrinsic::x86_avx2_packssdw:
2007 case llvm::Intrinsic::x86_avx2_packusdw:
2008 return llvm::Intrinsic::x86_avx2_packssdw;
2010 case llvm::Intrinsic::x86_mmx_packsswb:
2011 case llvm::Intrinsic::x86_mmx_packuswb:
2012 return llvm::Intrinsic::x86_mmx_packsswb;
2014 case llvm::Intrinsic::x86_mmx_packssdw:
2015 return llvm::Intrinsic::x86_mmx_packssdw;
2017 llvm_unreachable("unexpected intrinsic id");
2021 // \brief Instrument vector pack instrinsic.
2023 // This function instruments intrinsics like x86_mmx_packsswb, that
2024 // packs elements of 2 input vectors into half as many bits with saturation.
2025 // Shadow is propagated with the signed variant of the same intrinsic applied
2026 // to sext(Sa != zeroinitializer), sext(Sb != zeroinitializer).
2027 // EltSizeInBits is used only for x86mmx arguments.
2028 void handleVectorPackIntrinsic(IntrinsicInst &I, unsigned EltSizeInBits = 0) {
2029 assert(I.getNumArgOperands() == 2);
2030 bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
2031 IRBuilder<> IRB(&I);
2032 Value *S1 = getShadow(&I, 0);
2033 Value *S2 = getShadow(&I, 1);
2034 assert(isX86_MMX || S1->getType()->isVectorTy());
2036 // SExt and ICmpNE below must apply to individual elements of input vectors.
2037 // In case of x86mmx arguments, cast them to appropriate vector types and
2039 Type *T = isX86_MMX ? getMMXVectorTy(EltSizeInBits) : S1->getType();
2041 S1 = IRB.CreateBitCast(S1, T);
2042 S2 = IRB.CreateBitCast(S2, T);
2044 Value *S1_ext = IRB.CreateSExt(
2045 IRB.CreateICmpNE(S1, llvm::Constant::getNullValue(T)), T);
2046 Value *S2_ext = IRB.CreateSExt(
2047 IRB.CreateICmpNE(S2, llvm::Constant::getNullValue(T)), T);
2049 Type *X86_MMXTy = Type::getX86_MMXTy(*MS.C);
2050 S1_ext = IRB.CreateBitCast(S1_ext, X86_MMXTy);
2051 S2_ext = IRB.CreateBitCast(S2_ext, X86_MMXTy);
2054 Function *ShadowFn = Intrinsic::getDeclaration(
2055 F.getParent(), getSignedPackIntrinsic(I.getIntrinsicID()));
2057 Value *S = IRB.CreateCall2(ShadowFn, S1_ext, S2_ext, "_msprop_vector_pack");
2058 if (isX86_MMX) S = IRB.CreateBitCast(S, getShadowTy(&I));
2060 setOriginForNaryOp(I);
2063 // \brief Instrument sum-of-absolute-differencies intrinsic.
2064 void handleVectorSadIntrinsic(IntrinsicInst &I) {
2065 const unsigned SignificantBitsPerResultElement = 16;
2066 bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
2067 Type *ResTy = isX86_MMX ? IntegerType::get(*MS.C, 64) : I.getType();
2068 unsigned ZeroBitsPerResultElement =
2069 ResTy->getScalarSizeInBits() - SignificantBitsPerResultElement;
2071 IRBuilder<> IRB(&I);
2072 Value *S = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
2073 S = IRB.CreateBitCast(S, ResTy);
2074 S = IRB.CreateSExt(IRB.CreateICmpNE(S, Constant::getNullValue(ResTy)),
2076 S = IRB.CreateLShr(S, ZeroBitsPerResultElement);
2077 S = IRB.CreateBitCast(S, getShadowTy(&I));
2079 setOriginForNaryOp(I);
2082 // \brief Instrument multiply-add intrinsic.
2083 void handleVectorPmaddIntrinsic(IntrinsicInst &I,
2084 unsigned EltSizeInBits = 0) {
2085 bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
2086 Type *ResTy = isX86_MMX ? getMMXVectorTy(EltSizeInBits * 2) : I.getType();
2087 IRBuilder<> IRB(&I);
2088 Value *S = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
2089 S = IRB.CreateBitCast(S, ResTy);
2090 S = IRB.CreateSExt(IRB.CreateICmpNE(S, Constant::getNullValue(ResTy)),
2092 S = IRB.CreateBitCast(S, getShadowTy(&I));
2094 setOriginForNaryOp(I);
2097 void visitIntrinsicInst(IntrinsicInst &I) {
2098 switch (I.getIntrinsicID()) {
2099 case llvm::Intrinsic::bswap:
2102 case llvm::Intrinsic::x86_avx512_cvtsd2usi64:
2103 case llvm::Intrinsic::x86_avx512_cvtsd2usi:
2104 case llvm::Intrinsic::x86_avx512_cvtss2usi64:
2105 case llvm::Intrinsic::x86_avx512_cvtss2usi:
2106 case llvm::Intrinsic::x86_avx512_cvttss2usi64:
2107 case llvm::Intrinsic::x86_avx512_cvttss2usi:
2108 case llvm::Intrinsic::x86_avx512_cvttsd2usi64:
2109 case llvm::Intrinsic::x86_avx512_cvttsd2usi:
2110 case llvm::Intrinsic::x86_avx512_cvtusi2sd:
2111 case llvm::Intrinsic::x86_avx512_cvtusi2ss:
2112 case llvm::Intrinsic::x86_avx512_cvtusi642sd:
2113 case llvm::Intrinsic::x86_avx512_cvtusi642ss:
2114 case llvm::Intrinsic::x86_sse2_cvtsd2si64:
2115 case llvm::Intrinsic::x86_sse2_cvtsd2si:
2116 case llvm::Intrinsic::x86_sse2_cvtsd2ss:
2117 case llvm::Intrinsic::x86_sse2_cvtsi2sd:
2118 case llvm::Intrinsic::x86_sse2_cvtsi642sd:
2119 case llvm::Intrinsic::x86_sse2_cvtss2sd:
2120 case llvm::Intrinsic::x86_sse2_cvttsd2si64:
2121 case llvm::Intrinsic::x86_sse2_cvttsd2si:
2122 case llvm::Intrinsic::x86_sse_cvtsi2ss:
2123 case llvm::Intrinsic::x86_sse_cvtsi642ss:
2124 case llvm::Intrinsic::x86_sse_cvtss2si64:
2125 case llvm::Intrinsic::x86_sse_cvtss2si:
2126 case llvm::Intrinsic::x86_sse_cvttss2si64:
2127 case llvm::Intrinsic::x86_sse_cvttss2si:
2128 handleVectorConvertIntrinsic(I, 1);
2130 case llvm::Intrinsic::x86_sse2_cvtdq2pd:
2131 case llvm::Intrinsic::x86_sse2_cvtps2pd:
2132 case llvm::Intrinsic::x86_sse_cvtps2pi:
2133 case llvm::Intrinsic::x86_sse_cvttps2pi:
2134 handleVectorConvertIntrinsic(I, 2);
2136 case llvm::Intrinsic::x86_avx512_psll_dq:
2137 case llvm::Intrinsic::x86_avx512_psrl_dq:
2138 case llvm::Intrinsic::x86_avx2_psll_w:
2139 case llvm::Intrinsic::x86_avx2_psll_d:
2140 case llvm::Intrinsic::x86_avx2_psll_q:
2141 case llvm::Intrinsic::x86_avx2_pslli_w:
2142 case llvm::Intrinsic::x86_avx2_pslli_d:
2143 case llvm::Intrinsic::x86_avx2_pslli_q:
2144 case llvm::Intrinsic::x86_avx2_psll_dq:
2145 case llvm::Intrinsic::x86_avx2_psrl_w:
2146 case llvm::Intrinsic::x86_avx2_psrl_d:
2147 case llvm::Intrinsic::x86_avx2_psrl_q:
2148 case llvm::Intrinsic::x86_avx2_psra_w:
2149 case llvm::Intrinsic::x86_avx2_psra_d:
2150 case llvm::Intrinsic::x86_avx2_psrli_w:
2151 case llvm::Intrinsic::x86_avx2_psrli_d:
2152 case llvm::Intrinsic::x86_avx2_psrli_q:
2153 case llvm::Intrinsic::x86_avx2_psrai_w:
2154 case llvm::Intrinsic::x86_avx2_psrai_d:
2155 case llvm::Intrinsic::x86_avx2_psrl_dq:
2156 case llvm::Intrinsic::x86_sse2_psll_w:
2157 case llvm::Intrinsic::x86_sse2_psll_d:
2158 case llvm::Intrinsic::x86_sse2_psll_q:
2159 case llvm::Intrinsic::x86_sse2_pslli_w:
2160 case llvm::Intrinsic::x86_sse2_pslli_d:
2161 case llvm::Intrinsic::x86_sse2_pslli_q:
2162 case llvm::Intrinsic::x86_sse2_psll_dq:
2163 case llvm::Intrinsic::x86_sse2_psrl_w:
2164 case llvm::Intrinsic::x86_sse2_psrl_d:
2165 case llvm::Intrinsic::x86_sse2_psrl_q:
2166 case llvm::Intrinsic::x86_sse2_psra_w:
2167 case llvm::Intrinsic::x86_sse2_psra_d:
2168 case llvm::Intrinsic::x86_sse2_psrli_w:
2169 case llvm::Intrinsic::x86_sse2_psrli_d:
2170 case llvm::Intrinsic::x86_sse2_psrli_q:
2171 case llvm::Intrinsic::x86_sse2_psrai_w:
2172 case llvm::Intrinsic::x86_sse2_psrai_d:
2173 case llvm::Intrinsic::x86_sse2_psrl_dq:
2174 case llvm::Intrinsic::x86_mmx_psll_w:
2175 case llvm::Intrinsic::x86_mmx_psll_d:
2176 case llvm::Intrinsic::x86_mmx_psll_q:
2177 case llvm::Intrinsic::x86_mmx_pslli_w:
2178 case llvm::Intrinsic::x86_mmx_pslli_d:
2179 case llvm::Intrinsic::x86_mmx_pslli_q:
2180 case llvm::Intrinsic::x86_mmx_psrl_w:
2181 case llvm::Intrinsic::x86_mmx_psrl_d:
2182 case llvm::Intrinsic::x86_mmx_psrl_q:
2183 case llvm::Intrinsic::x86_mmx_psra_w:
2184 case llvm::Intrinsic::x86_mmx_psra_d:
2185 case llvm::Intrinsic::x86_mmx_psrli_w:
2186 case llvm::Intrinsic::x86_mmx_psrli_d:
2187 case llvm::Intrinsic::x86_mmx_psrli_q:
2188 case llvm::Intrinsic::x86_mmx_psrai_w:
2189 case llvm::Intrinsic::x86_mmx_psrai_d:
2190 handleVectorShiftIntrinsic(I, /* Variable */ false);
2192 case llvm::Intrinsic::x86_avx2_psllv_d:
2193 case llvm::Intrinsic::x86_avx2_psllv_d_256:
2194 case llvm::Intrinsic::x86_avx2_psllv_q:
2195 case llvm::Intrinsic::x86_avx2_psllv_q_256:
2196 case llvm::Intrinsic::x86_avx2_psrlv_d:
2197 case llvm::Intrinsic::x86_avx2_psrlv_d_256:
2198 case llvm::Intrinsic::x86_avx2_psrlv_q:
2199 case llvm::Intrinsic::x86_avx2_psrlv_q_256:
2200 case llvm::Intrinsic::x86_avx2_psrav_d:
2201 case llvm::Intrinsic::x86_avx2_psrav_d_256:
2202 handleVectorShiftIntrinsic(I, /* Variable */ true);
2205 // Byte shifts are not implemented.
2206 // case llvm::Intrinsic::x86_avx512_psll_dq_bs:
2207 // case llvm::Intrinsic::x86_avx512_psrl_dq_bs:
2208 // case llvm::Intrinsic::x86_avx2_psll_dq_bs:
2209 // case llvm::Intrinsic::x86_avx2_psrl_dq_bs:
2210 // case llvm::Intrinsic::x86_sse2_psll_dq_bs:
2211 // case llvm::Intrinsic::x86_sse2_psrl_dq_bs:
2213 case llvm::Intrinsic::x86_sse2_packsswb_128:
2214 case llvm::Intrinsic::x86_sse2_packssdw_128:
2215 case llvm::Intrinsic::x86_sse2_packuswb_128:
2216 case llvm::Intrinsic::x86_sse41_packusdw:
2217 case llvm::Intrinsic::x86_avx2_packsswb:
2218 case llvm::Intrinsic::x86_avx2_packssdw:
2219 case llvm::Intrinsic::x86_avx2_packuswb:
2220 case llvm::Intrinsic::x86_avx2_packusdw:
2221 handleVectorPackIntrinsic(I);
2224 case llvm::Intrinsic::x86_mmx_packsswb:
2225 case llvm::Intrinsic::x86_mmx_packuswb:
2226 handleVectorPackIntrinsic(I, 16);
2229 case llvm::Intrinsic::x86_mmx_packssdw:
2230 handleVectorPackIntrinsic(I, 32);
2233 case llvm::Intrinsic::x86_mmx_psad_bw:
2234 case llvm::Intrinsic::x86_sse2_psad_bw:
2235 case llvm::Intrinsic::x86_avx2_psad_bw:
2236 handleVectorSadIntrinsic(I);
2239 case llvm::Intrinsic::x86_sse2_pmadd_wd:
2240 case llvm::Intrinsic::x86_avx2_pmadd_wd:
2241 case llvm::Intrinsic::x86_ssse3_pmadd_ub_sw_128:
2242 case llvm::Intrinsic::x86_avx2_pmadd_ub_sw:
2243 handleVectorPmaddIntrinsic(I);
2246 case llvm::Intrinsic::x86_ssse3_pmadd_ub_sw:
2247 handleVectorPmaddIntrinsic(I, 8);
2250 case llvm::Intrinsic::x86_mmx_pmadd_wd:
2251 handleVectorPmaddIntrinsic(I, 16);
2255 if (!handleUnknownIntrinsic(I))
2256 visitInstruction(I);
2261 void visitCallSite(CallSite CS) {
2262 Instruction &I = *CS.getInstruction();
2263 assert((CS.isCall() || CS.isInvoke()) && "Unknown type of CallSite");
2265 CallInst *Call = cast<CallInst>(&I);
2267 // For inline asm, do the usual thing: check argument shadow and mark all
2268 // outputs as clean. Note that any side effects of the inline asm that are
2269 // not immediately visible in its constraints are not handled.
2270 if (Call->isInlineAsm()) {
2271 visitInstruction(I);
2275 // Allow only tail calls with the same types, otherwise
2276 // we may have a false positive: shadow for a non-void RetVal
2277 // will get propagated to a void RetVal.
2278 if (Call->isTailCall() && Call->getType() != Call->getParent()->getType())
2279 Call->setTailCall(false);
2281 assert(!isa<IntrinsicInst>(&I) && "intrinsics are handled elsewhere");
2283 // We are going to insert code that relies on the fact that the callee
2284 // will become a non-readonly function after it is instrumented by us. To
2285 // prevent this code from being optimized out, mark that function
2286 // non-readonly in advance.
2287 if (Function *Func = Call->getCalledFunction()) {
2288 // Clear out readonly/readnone attributes.
2290 B.addAttribute(Attribute::ReadOnly)
2291 .addAttribute(Attribute::ReadNone);
2292 Func->removeAttributes(AttributeSet::FunctionIndex,
2293 AttributeSet::get(Func->getContext(),
2294 AttributeSet::FunctionIndex,
2298 IRBuilder<> IRB(&I);
2300 if (MS.WrapIndirectCalls && !CS.getCalledFunction())
2301 IndirectCallList.push_back(CS);
2303 unsigned ArgOffset = 0;
2304 DEBUG(dbgs() << " CallSite: " << I << "\n");
2305 for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end();
2306 ArgIt != End; ++ArgIt) {
2308 unsigned i = ArgIt - CS.arg_begin();
2309 if (!A->getType()->isSized()) {
2310 DEBUG(dbgs() << "Arg " << i << " is not sized: " << I << "\n");
2314 Value *Store = nullptr;
2315 // Compute the Shadow for arg even if it is ByVal, because
2316 // in that case getShadow() will copy the actual arg shadow to
2317 // __msan_param_tls.
2318 Value *ArgShadow = getShadow(A);
2319 Value *ArgShadowBase = getShadowPtrForArgument(A, IRB, ArgOffset);
2320 DEBUG(dbgs() << " Arg#" << i << ": " << *A <<
2321 " Shadow: " << *ArgShadow << "\n");
2322 if (CS.paramHasAttr(i + 1, Attribute::ByVal)) {
2323 assert(A->getType()->isPointerTy() &&
2324 "ByVal argument is not a pointer!");
2325 Size = MS.DL->getTypeAllocSize(A->getType()->getPointerElementType());
2326 unsigned Alignment = CS.getParamAlignment(i + 1);
2327 Store = IRB.CreateMemCpy(ArgShadowBase,
2328 getShadowPtr(A, Type::getInt8Ty(*MS.C), IRB),
2331 Size = MS.DL->getTypeAllocSize(A->getType());
2332 Store = IRB.CreateAlignedStore(ArgShadow, ArgShadowBase,
2333 kShadowTLSAlignment);
2335 if (MS.TrackOrigins)
2336 IRB.CreateStore(getOrigin(A),
2337 getOriginPtrForArgument(A, IRB, ArgOffset));
2339 assert(Size != 0 && Store != nullptr);
2340 DEBUG(dbgs() << " Param:" << *Store << "\n");
2341 ArgOffset += DataLayout::RoundUpAlignment(Size, 8);
2343 DEBUG(dbgs() << " done with call args\n");
2346 cast<FunctionType>(CS.getCalledValue()->getType()->getContainedType(0));
2347 if (FT->isVarArg()) {
2348 VAHelper->visitCallSite(CS, IRB);
2351 // Now, get the shadow for the RetVal.
2352 if (!I.getType()->isSized()) return;
2353 IRBuilder<> IRBBefore(&I);
2354 // Until we have full dynamic coverage, make sure the retval shadow is 0.
2355 Value *Base = getShadowPtrForRetval(&I, IRBBefore);
2356 IRBBefore.CreateAlignedStore(getCleanShadow(&I), Base, kShadowTLSAlignment);
2357 Instruction *NextInsn = nullptr;
2359 NextInsn = I.getNextNode();
2361 BasicBlock *NormalDest = cast<InvokeInst>(&I)->getNormalDest();
2362 if (!NormalDest->getSinglePredecessor()) {
2363 // FIXME: this case is tricky, so we are just conservative here.
2364 // Perhaps we need to split the edge between this BB and NormalDest,
2365 // but a naive attempt to use SplitEdge leads to a crash.
2366 setShadow(&I, getCleanShadow(&I));
2367 setOrigin(&I, getCleanOrigin());
2370 NextInsn = NormalDest->getFirstInsertionPt();
2372 "Could not find insertion point for retval shadow load");
2374 IRBuilder<> IRBAfter(NextInsn);
2375 Value *RetvalShadow =
2376 IRBAfter.CreateAlignedLoad(getShadowPtrForRetval(&I, IRBAfter),
2377 kShadowTLSAlignment, "_msret");
2378 setShadow(&I, RetvalShadow);
2379 if (MS.TrackOrigins)
2380 setOrigin(&I, IRBAfter.CreateLoad(getOriginPtrForRetval(IRBAfter)));
2383 void visitReturnInst(ReturnInst &I) {
2384 IRBuilder<> IRB(&I);
2385 Value *RetVal = I.getReturnValue();
2386 if (!RetVal) return;
2387 Value *ShadowPtr = getShadowPtrForRetval(RetVal, IRB);
2388 if (CheckReturnValue) {
2389 insertShadowCheck(RetVal, &I);
2390 Value *Shadow = getCleanShadow(RetVal);
2391 IRB.CreateAlignedStore(Shadow, ShadowPtr, kShadowTLSAlignment);
2393 Value *Shadow = getShadow(RetVal);
2394 IRB.CreateAlignedStore(Shadow, ShadowPtr, kShadowTLSAlignment);
2395 // FIXME: make it conditional if ClStoreCleanOrigin==0
2396 if (MS.TrackOrigins)
2397 IRB.CreateStore(getOrigin(RetVal), getOriginPtrForRetval(IRB));
2401 void visitPHINode(PHINode &I) {
2402 IRBuilder<> IRB(&I);
2403 ShadowPHINodes.push_back(&I);
2404 setShadow(&I, IRB.CreatePHI(getShadowTy(&I), I.getNumIncomingValues(),
2406 if (MS.TrackOrigins)
2407 setOrigin(&I, IRB.CreatePHI(MS.OriginTy, I.getNumIncomingValues(),
2411 void visitAllocaInst(AllocaInst &I) {
2412 setShadow(&I, getCleanShadow(&I));
2413 IRBuilder<> IRB(I.getNextNode());
2414 uint64_t Size = MS.DL->getTypeAllocSize(I.getAllocatedType());
2415 if (PoisonStack && ClPoisonStackWithCall) {
2416 IRB.CreateCall2(MS.MsanPoisonStackFn,
2417 IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()),
2418 ConstantInt::get(MS.IntptrTy, Size));
2420 Value *ShadowBase = getShadowPtr(&I, Type::getInt8PtrTy(*MS.C), IRB);
2421 Value *PoisonValue = IRB.getInt8(PoisonStack ? ClPoisonStackPattern : 0);
2422 IRB.CreateMemSet(ShadowBase, PoisonValue, Size, I.getAlignment());
2425 if (PoisonStack && MS.TrackOrigins) {
2426 setOrigin(&I, getCleanOrigin());
2427 SmallString<2048> StackDescriptionStorage;
2428 raw_svector_ostream StackDescription(StackDescriptionStorage);
2429 // We create a string with a description of the stack allocation and
2430 // pass it into __msan_set_alloca_origin.
2431 // It will be printed by the run-time if stack-originated UMR is found.
2432 // The first 4 bytes of the string are set to '----' and will be replaced
2433 // by __msan_va_arg_overflow_size_tls at the first call.
2434 StackDescription << "----" << I.getName() << "@" << F.getName();
2436 createPrivateNonConstGlobalForString(*F.getParent(),
2437 StackDescription.str());
2439 IRB.CreateCall4(MS.MsanSetAllocaOrigin4Fn,
2440 IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()),
2441 ConstantInt::get(MS.IntptrTy, Size),
2442 IRB.CreatePointerCast(Descr, IRB.getInt8PtrTy()),
2443 IRB.CreatePointerCast(&F, MS.IntptrTy));
2447 void visitSelectInst(SelectInst& I) {
2448 IRBuilder<> IRB(&I);
2449 // a = select b, c, d
2450 Value *B = I.getCondition();
2451 Value *C = I.getTrueValue();
2452 Value *D = I.getFalseValue();
2453 Value *Sb = getShadow(B);
2454 Value *Sc = getShadow(C);
2455 Value *Sd = getShadow(D);
2457 // Result shadow if condition shadow is 0.
2458 Value *Sa0 = IRB.CreateSelect(B, Sc, Sd);
2460 if (I.getType()->isAggregateType()) {
2461 // To avoid "sign extending" i1 to an arbitrary aggregate type, we just do
2462 // an extra "select". This results in much more compact IR.
2463 // Sa = select Sb, poisoned, (select b, Sc, Sd)
2464 Sa1 = getPoisonedShadow(getShadowTy(I.getType()));
2466 // Sa = select Sb, [ (c^d) | Sc | Sd ], [ b ? Sc : Sd ]
2467 // If Sb (condition is poisoned), look for bits in c and d that are equal
2468 // and both unpoisoned.
2469 // If !Sb (condition is unpoisoned), simply pick one of Sc and Sd.
2471 // Cast arguments to shadow-compatible type.
2472 C = CreateAppToShadowCast(IRB, C);
2473 D = CreateAppToShadowCast(IRB, D);
2475 // Result shadow if condition shadow is 1.
2476 Sa1 = IRB.CreateOr(IRB.CreateXor(C, D), IRB.CreateOr(Sc, Sd));
2478 Value *Sa = IRB.CreateSelect(Sb, Sa1, Sa0, "_msprop_select");
2480 if (MS.TrackOrigins) {
2481 // Origins are always i32, so any vector conditions must be flattened.
2482 // FIXME: consider tracking vector origins for app vectors?
2483 if (B->getType()->isVectorTy()) {
2484 Type *FlatTy = getShadowTyNoVec(B->getType());
2485 B = IRB.CreateICmpNE(IRB.CreateBitCast(B, FlatTy),
2486 ConstantInt::getNullValue(FlatTy));
2487 Sb = IRB.CreateICmpNE(IRB.CreateBitCast(Sb, FlatTy),
2488 ConstantInt::getNullValue(FlatTy));
2490 // a = select b, c, d
2491 // Oa = Sb ? Ob : (b ? Oc : Od)
2492 setOrigin(&I, IRB.CreateSelect(
2493 Sb, getOrigin(I.getCondition()),
2494 IRB.CreateSelect(B, getOrigin(C), getOrigin(D))));
2498 void visitLandingPadInst(LandingPadInst &I) {
2500 // See http://code.google.com/p/memory-sanitizer/issues/detail?id=1
2501 setShadow(&I, getCleanShadow(&I));
2502 setOrigin(&I, getCleanOrigin());
2505 void visitGetElementPtrInst(GetElementPtrInst &I) {
2509 void visitExtractValueInst(ExtractValueInst &I) {
2510 IRBuilder<> IRB(&I);
2511 Value *Agg = I.getAggregateOperand();
2512 DEBUG(dbgs() << "ExtractValue: " << I << "\n");
2513 Value *AggShadow = getShadow(Agg);
2514 DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n");
2515 Value *ResShadow = IRB.CreateExtractValue(AggShadow, I.getIndices());
2516 DEBUG(dbgs() << " ResShadow: " << *ResShadow << "\n");
2517 setShadow(&I, ResShadow);
2518 setOriginForNaryOp(I);
2521 void visitInsertValueInst(InsertValueInst &I) {
2522 IRBuilder<> IRB(&I);
2523 DEBUG(dbgs() << "InsertValue: " << I << "\n");
2524 Value *AggShadow = getShadow(I.getAggregateOperand());
2525 Value *InsShadow = getShadow(I.getInsertedValueOperand());
2526 DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n");
2527 DEBUG(dbgs() << " InsShadow: " << *InsShadow << "\n");
2528 Value *Res = IRB.CreateInsertValue(AggShadow, InsShadow, I.getIndices());
2529 DEBUG(dbgs() << " Res: " << *Res << "\n");
2531 setOriginForNaryOp(I);
2534 void dumpInst(Instruction &I) {
2535 if (CallInst *CI = dyn_cast<CallInst>(&I)) {
2536 errs() << "ZZZ call " << CI->getCalledFunction()->getName() << "\n";
2538 errs() << "ZZZ " << I.getOpcodeName() << "\n";
2540 errs() << "QQQ " << I << "\n";
2543 void visitResumeInst(ResumeInst &I) {
2544 DEBUG(dbgs() << "Resume: " << I << "\n");
2545 // Nothing to do here.
2548 void visitInstruction(Instruction &I) {
2549 // Everything else: stop propagating and check for poisoned shadow.
2550 if (ClDumpStrictInstructions)
2552 DEBUG(dbgs() << "DEFAULT: " << I << "\n");
2553 for (size_t i = 0, n = I.getNumOperands(); i < n; i++)
2554 insertShadowCheck(I.getOperand(i), &I);
2555 setShadow(&I, getCleanShadow(&I));
2556 setOrigin(&I, getCleanOrigin());
2560 /// \brief AMD64-specific implementation of VarArgHelper.
2561 struct VarArgAMD64Helper : public VarArgHelper {
2562 // An unfortunate workaround for asymmetric lowering of va_arg stuff.
2563 // See a comment in visitCallSite for more details.
2564 static const unsigned AMD64GpEndOffset = 48; // AMD64 ABI Draft 0.99.6 p3.5.7
2565 static const unsigned AMD64FpEndOffset = 176;
2568 MemorySanitizer &MS;
2569 MemorySanitizerVisitor &MSV;
2570 Value *VAArgTLSCopy;
2571 Value *VAArgOverflowSize;
2573 SmallVector<CallInst*, 16> VAStartInstrumentationList;
2575 VarArgAMD64Helper(Function &F, MemorySanitizer &MS,
2576 MemorySanitizerVisitor &MSV)
2577 : F(F), MS(MS), MSV(MSV), VAArgTLSCopy(nullptr),
2578 VAArgOverflowSize(nullptr) {}
2580 enum ArgKind { AK_GeneralPurpose, AK_FloatingPoint, AK_Memory };
2582 ArgKind classifyArgument(Value* arg) {
2583 // A very rough approximation of X86_64 argument classification rules.
2584 Type *T = arg->getType();
2585 if (T->isFPOrFPVectorTy() || T->isX86_MMXTy())
2586 return AK_FloatingPoint;
2587 if (T->isIntegerTy() && T->getPrimitiveSizeInBits() <= 64)
2588 return AK_GeneralPurpose;
2589 if (T->isPointerTy())
2590 return AK_GeneralPurpose;
2594 // For VarArg functions, store the argument shadow in an ABI-specific format
2595 // that corresponds to va_list layout.
2596 // We do this because Clang lowers va_arg in the frontend, and this pass
2597 // only sees the low level code that deals with va_list internals.
2598 // A much easier alternative (provided that Clang emits va_arg instructions)
2599 // would have been to associate each live instance of va_list with a copy of
2600 // MSanParamTLS, and extract shadow on va_arg() call in the argument list
2602 void visitCallSite(CallSite &CS, IRBuilder<> &IRB) override {
2603 unsigned GpOffset = 0;
2604 unsigned FpOffset = AMD64GpEndOffset;
2605 unsigned OverflowOffset = AMD64FpEndOffset;
2606 for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end();
2607 ArgIt != End; ++ArgIt) {
2609 unsigned ArgNo = CS.getArgumentNo(ArgIt);
2610 bool IsByVal = CS.paramHasAttr(ArgNo + 1, Attribute::ByVal);
2612 // ByVal arguments always go to the overflow area.
2613 assert(A->getType()->isPointerTy());
2614 Type *RealTy = A->getType()->getPointerElementType();
2615 uint64_t ArgSize = MS.DL->getTypeAllocSize(RealTy);
2616 Value *Base = getShadowPtrForVAArgument(RealTy, IRB, OverflowOffset);
2617 OverflowOffset += DataLayout::RoundUpAlignment(ArgSize, 8);
2618 IRB.CreateMemCpy(Base, MSV.getShadowPtr(A, IRB.getInt8Ty(), IRB),
2619 ArgSize, kShadowTLSAlignment);
2621 ArgKind AK = classifyArgument(A);
2622 if (AK == AK_GeneralPurpose && GpOffset >= AMD64GpEndOffset)
2624 if (AK == AK_FloatingPoint && FpOffset >= AMD64FpEndOffset)
2628 case AK_GeneralPurpose:
2629 Base = getShadowPtrForVAArgument(A->getType(), IRB, GpOffset);
2632 case AK_FloatingPoint:
2633 Base = getShadowPtrForVAArgument(A->getType(), IRB, FpOffset);
2637 uint64_t ArgSize = MS.DL->getTypeAllocSize(A->getType());
2638 Base = getShadowPtrForVAArgument(A->getType(), IRB, OverflowOffset);
2639 OverflowOffset += DataLayout::RoundUpAlignment(ArgSize, 8);
2641 IRB.CreateAlignedStore(MSV.getShadow(A), Base, kShadowTLSAlignment);
2644 Constant *OverflowSize =
2645 ConstantInt::get(IRB.getInt64Ty(), OverflowOffset - AMD64FpEndOffset);
2646 IRB.CreateStore(OverflowSize, MS.VAArgOverflowSizeTLS);
2649 /// \brief Compute the shadow address for a given va_arg.
2650 Value *getShadowPtrForVAArgument(Type *Ty, IRBuilder<> &IRB,
2652 Value *Base = IRB.CreatePointerCast(MS.VAArgTLS, MS.IntptrTy);
2653 Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
2654 return IRB.CreateIntToPtr(Base, PointerType::get(MSV.getShadowTy(Ty), 0),
2658 void visitVAStartInst(VAStartInst &I) override {
2659 IRBuilder<> IRB(&I);
2660 VAStartInstrumentationList.push_back(&I);
2661 Value *VAListTag = I.getArgOperand(0);
2662 Value *ShadowPtr = MSV.getShadowPtr(VAListTag, IRB.getInt8Ty(), IRB);
2664 // Unpoison the whole __va_list_tag.
2665 // FIXME: magic ABI constants.
2666 IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
2667 /* size */24, /* alignment */8, false);
2670 void visitVACopyInst(VACopyInst &I) override {
2671 IRBuilder<> IRB(&I);
2672 Value *VAListTag = I.getArgOperand(0);
2673 Value *ShadowPtr = MSV.getShadowPtr(VAListTag, IRB.getInt8Ty(), IRB);
2675 // Unpoison the whole __va_list_tag.
2676 // FIXME: magic ABI constants.
2677 IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
2678 /* size */24, /* alignment */8, false);
2681 void finalizeInstrumentation() override {
2682 assert(!VAArgOverflowSize && !VAArgTLSCopy &&
2683 "finalizeInstrumentation called twice");
2684 if (!VAStartInstrumentationList.empty()) {
2685 // If there is a va_start in this function, make a backup copy of
2686 // va_arg_tls somewhere in the function entry block.
2687 IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
2688 VAArgOverflowSize = IRB.CreateLoad(MS.VAArgOverflowSizeTLS);
2690 IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, AMD64FpEndOffset),
2692 VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
2693 IRB.CreateMemCpy(VAArgTLSCopy, MS.VAArgTLS, CopySize, 8);
2696 // Instrument va_start.
2697 // Copy va_list shadow from the backup copy of the TLS contents.
2698 for (size_t i = 0, n = VAStartInstrumentationList.size(); i < n; i++) {
2699 CallInst *OrigInst = VAStartInstrumentationList[i];
2700 IRBuilder<> IRB(OrigInst->getNextNode());
2701 Value *VAListTag = OrigInst->getArgOperand(0);
2703 Value *RegSaveAreaPtrPtr =
2705 IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
2706 ConstantInt::get(MS.IntptrTy, 16)),
2707 Type::getInt64PtrTy(*MS.C));
2708 Value *RegSaveAreaPtr = IRB.CreateLoad(RegSaveAreaPtrPtr);
2709 Value *RegSaveAreaShadowPtr =
2710 MSV.getShadowPtr(RegSaveAreaPtr, IRB.getInt8Ty(), IRB);
2711 IRB.CreateMemCpy(RegSaveAreaShadowPtr, VAArgTLSCopy,
2712 AMD64FpEndOffset, 16);
2714 Value *OverflowArgAreaPtrPtr =
2716 IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
2717 ConstantInt::get(MS.IntptrTy, 8)),
2718 Type::getInt64PtrTy(*MS.C));
2719 Value *OverflowArgAreaPtr = IRB.CreateLoad(OverflowArgAreaPtrPtr);
2720 Value *OverflowArgAreaShadowPtr =
2721 MSV.getShadowPtr(OverflowArgAreaPtr, IRB.getInt8Ty(), IRB);
2722 Value *SrcPtr = IRB.CreateConstGEP1_32(VAArgTLSCopy, AMD64FpEndOffset);
2723 IRB.CreateMemCpy(OverflowArgAreaShadowPtr, SrcPtr, VAArgOverflowSize, 16);
2728 /// \brief A no-op implementation of VarArgHelper.
2729 struct VarArgNoOpHelper : public VarArgHelper {
2730 VarArgNoOpHelper(Function &F, MemorySanitizer &MS,
2731 MemorySanitizerVisitor &MSV) {}
2733 void visitCallSite(CallSite &CS, IRBuilder<> &IRB) override {}
2735 void visitVAStartInst(VAStartInst &I) override {}
2737 void visitVACopyInst(VACopyInst &I) override {}
2739 void finalizeInstrumentation() override {}
2742 VarArgHelper *CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
2743 MemorySanitizerVisitor &Visitor) {
2744 // VarArg handling is only implemented on AMD64. False positives are possible
2745 // on other platforms.
2746 llvm::Triple TargetTriple(Func.getParent()->getTargetTriple());
2747 if (TargetTriple.getArch() == llvm::Triple::x86_64)
2748 return new VarArgAMD64Helper(Func, Msan, Visitor);
2750 return new VarArgNoOpHelper(Func, Msan, Visitor);
2755 bool MemorySanitizer::runOnFunction(Function &F) {
2756 MemorySanitizerVisitor Visitor(F, *this);
2758 // Clear out readonly/readnone attributes.
2760 B.addAttribute(Attribute::ReadOnly)
2761 .addAttribute(Attribute::ReadNone);
2762 F.removeAttributes(AttributeSet::FunctionIndex,
2763 AttributeSet::get(F.getContext(),
2764 AttributeSet::FunctionIndex, B));
2766 return Visitor.runOnFunction();