[llvm-commits] [llvm] r168866 - in /llvm/trunk: include/llvm/InitializePasses.h include/llvm/Transforms/Instrumentation.h lib/Transforms/Instrumentation/CMakeLists.txt lib/Transforms/Instrumentation/Instrumentation.cpp lib/Transforms/Instrumentation/MemorySanitizer.cpp test/Instrumentation/MemorySanitizer/ test/Instrumentation/MemorySanitizer/lit.local.cfg test/Instrumentation/MemorySanitizer/msan_basic.ll
David Blaikie
dblaikie at gmail.com
Thu Nov 29 08:52:38 PST 2012
On Thu, Nov 29, 2012 at 4:50 AM, Kostya Serebryany <kcc at google.com> wrote:
> Do we really want changes like this?
We generally try to keep selfhosted Clang building warning-free.
Several of us build with -Werror by default so warnings like this
break the build. If the warning is bad & can be fixed, we'll fix it in
Clang but that's unfortunately not the case for these preprocessor
related unuses.
(tl;dr: yes)
- David
>
> DEBUG(dbgs() << "No shadow: " << *V << "\n" << *(I->getParent()));
> + (void)I;
> assert(Shadow && "No shadow for a value");
>
> --kcc
>
>
> On Thu, Nov 29, 2012 at 4:44 PM, NAKAMURA Takumi <geek4civic at gmail.com>
> wrote:
>>
>> Evgeniy, could you apply patches to suppress warnings?
>>
>> ...Takumi
>>
>> 2012/11/29 Evgeniy Stepanov <eugeni.stepanov at gmail.com>:
>> > Author: eugenis
>> > Date: Thu Nov 29 03:57:20 2012
>> > New Revision: 168866
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=168866&view=rev
>> > Log:
>> > Initial commit of MemorySanitizer.
>> >
>> > Compiler pass only.
>> >
>> > Added:
>> > llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
>> > (with props)
>> > llvm/trunk/test/Instrumentation/MemorySanitizer/
>> > llvm/trunk/test/Instrumentation/MemorySanitizer/lit.local.cfg
>> > llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll
>> > Modified:
>> > llvm/trunk/include/llvm/InitializePasses.h
>> > llvm/trunk/include/llvm/Transforms/Instrumentation.h
>> > llvm/trunk/lib/Transforms/Instrumentation/CMakeLists.txt
>> > llvm/trunk/lib/Transforms/Instrumentation/Instrumentation.cpp
>> >
>> > Modified: llvm/trunk/include/llvm/InitializePasses.h
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/InitializePasses.h?rev=168866&r1=168865&r2=168866&view=diff
>> >
>> > ==============================================================================
>> > --- llvm/trunk/include/llvm/InitializePasses.h (original)
>> > +++ llvm/trunk/include/llvm/InitializePasses.h Thu Nov 29 03:57:20 2012
>> > @@ -111,6 +111,7 @@
>> > void initializeGCOVProfilerPass(PassRegistry&);
>> > void initializeAddressSanitizerPass(PassRegistry&);
>> > void initializeAddressSanitizerModulePass(PassRegistry&);
>> > +void initializeMemorySanitizerPass(PassRegistry&);
>> > void initializeThreadSanitizerPass(PassRegistry&);
>> > void initializeEarlyCSEPass(PassRegistry&);
>> > void initializeExpandISelPseudosPass(PassRegistry&);
>> >
>> > Modified: llvm/trunk/include/llvm/Transforms/Instrumentation.h
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Instrumentation.h?rev=168866&r1=168865&r2=168866&view=diff
>> >
>> > ==============================================================================
>> > --- llvm/trunk/include/llvm/Transforms/Instrumentation.h (original)
>> > +++ llvm/trunk/include/llvm/Transforms/Instrumentation.h Thu Nov 29
>> > 03:57:20 2012
>> > @@ -36,6 +36,8 @@
>> > // Insert AddressSanitizer (address sanity checking) instrumentation
>> > FunctionPass *createAddressSanitizerFunctionPass();
>> > ModulePass *createAddressSanitizerModulePass();
>> > +// Insert MemorySanitizer instrumentation (detection of uninitialized
>> > reads)
>> > +FunctionPass *createMemorySanitizerPass();
>> > // Insert ThreadSanitizer (race detection) instrumentation
>> > FunctionPass *createThreadSanitizerPass();
>> >
>> >
>> > Modified: llvm/trunk/lib/Transforms/Instrumentation/CMakeLists.txt
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/CMakeLists.txt?rev=168866&r1=168865&r2=168866&view=diff
>> >
>> > ==============================================================================
>> > --- llvm/trunk/lib/Transforms/Instrumentation/CMakeLists.txt (original)
>> > +++ llvm/trunk/lib/Transforms/Instrumentation/CMakeLists.txt Thu Nov 29
>> > 03:57:20 2012
>> > @@ -4,6 +4,7 @@
>> > BoundsChecking.cpp
>> > EdgeProfiling.cpp
>> > GCOVProfiling.cpp
>> > + MemorySanitizer.cpp
>> > Instrumentation.cpp
>> > OptimalEdgeProfiling.cpp
>> > PathProfiling.cpp
>> >
>> > Modified: llvm/trunk/lib/Transforms/Instrumentation/Instrumentation.cpp
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/Instrumentation.cpp?rev=168866&r1=168865&r2=168866&view=diff
>> >
>> > ==============================================================================
>> > --- llvm/trunk/lib/Transforms/Instrumentation/Instrumentation.cpp
>> > (original)
>> > +++ llvm/trunk/lib/Transforms/Instrumentation/Instrumentation.cpp Thu
>> > Nov 29 03:57:20 2012
>> > @@ -27,6 +27,7 @@
>> > initializeGCOVProfilerPass(Registry);
>> > initializeOptimalEdgeProfilerPass(Registry);
>> > initializePathProfilerPass(Registry);
>> > + initializeMemorySanitizerPass(Registry);
>> > initializeThreadSanitizerPass(Registry);
>> > }
>> >
>> >
>> > Added: llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp?rev=168866&view=auto
>> >
>> > ==============================================================================
>> > --- llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
>> > (added)
>> > +++ llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp Thu
>> > Nov 29 03:57:20 2012
>> > @@ -0,0 +1,1419 @@
>> > +//===-- MemorySanitizer.cpp - detector of uninitialized reads
>> > -------------===//
>> > +//
>> > +// The LLVM Compiler Infrastructure
>> > +//
>> > +// This file is distributed under the University of Illinois Open
>> > Source
>> > +// License. See LICENSE.TXT for details.
>> > +//
>> >
>> > +//===----------------------------------------------------------------------===//
>> > +/// \file
>> > +/// This file is a part of MemorySanitizer, a detector of uninitialized
>> > +/// reads.
>> > +///
>> > +/// Status: early prototype.
>> > +///
>> > +/// The algorithm of the tool is similar to Memcheck
>> > +/// (http://goo.gl/QKbem). We associate a few shadow bits with every
>> > +/// byte of the application memory, poison the shadow of the malloc-ed
>> > +/// or alloca-ed memory, load the shadow bits on every memory read,
>> > +/// propagate the shadow bits through some of the arithmetic
>> > +/// instruction (including MOV), store the shadow bits on every memory
>> > +/// write, report a bug on some other instructions (e.g. JMP) if the
>> > +/// associated shadow is poisoned.
>> > +///
>> > +/// But there are differences too. The first and the major one:
>> > +/// compiler instrumentation instead of binary instrumentation. This
>> > +/// gives us much better register allocation, possible compiler
>> > +/// optimizations and a fast start-up. But this brings the major issue
>> > +/// as well: msan needs to see all program events, including system
>> > +/// calls and reads/writes in system libraries, so we either need to
>> > +/// compile *everything* with msan or use a binary translation
>> > +/// component (e.g. DynamoRIO) to instrument pre-built libraries.
>> > +/// Another difference from Memcheck is that we use 8 shadow bits per
>> > +/// byte of application memory and use a direct shadow mapping. This
>> > +/// greatly simplifies the instrumentation code and avoids races on
>> > +/// shadow updates (Memcheck is single-threaded so races are not a
>> > +/// concern there. Memcheck uses 2 shadow bits per byte with a slow
>> > +/// path storage that uses 8 bits per byte).
>> > +///
>> > +/// The default value of shadow is 0, which means "clean" (not
>> > poisoned).
>> > +///
>> > +/// Every module initializer should call __msan_init to ensure that the
>> > +/// shadow memory is ready. On error, __msan_warning is called. Since
>> > +/// parameters and return values may be passed via registers, we have a
>> > +/// specialized thread-local shadow for return values
>> > +/// (__msan_retval_tls) and parameters (__msan_param_tls).
>> >
>> > +//===----------------------------------------------------------------------===//
>> > +
>> > +#define DEBUG_TYPE "msan"
>> > +
>> > +#include "BlackList.h"
>> > +#include "llvm/DataLayout.h"
>> > +#include "llvm/Function.h"
>> > +#include "llvm/InlineAsm.h"
>> > +#include "llvm/IntrinsicInst.h"
>> > +#include "llvm/IRBuilder.h"
>> > +#include "llvm/LLVMContext.h"
>> > +#include "llvm/MDBuilder.h"
>> > +#include "llvm/Module.h"
>> > +#include "llvm/Type.h"
>> > +#include "llvm/ADT/DepthFirstIterator.h"
>> > +#include "llvm/ADT/SmallString.h"
>> > +#include "llvm/ADT/SmallVector.h"
>> > +#include "llvm/ADT/ValueMap.h"
>> > +#include "llvm/Transforms/Instrumentation.h"
>> > +#include "llvm/Transforms/Utils/BasicBlockUtils.h"
>> > +#include "llvm/Transforms/Utils/ModuleUtils.h"
>> > +#include "llvm/Support/CommandLine.h"
>> > +#include "llvm/Support/Compiler.h"
>> > +#include "llvm/Support/Debug.h"
>> > +#include "llvm/Support/InstVisitor.h"
>> > +#include "llvm/Support/raw_ostream.h"
>> > +#include "llvm/Transforms/Instrumentation.h"
>> > +#include "llvm/Transforms/Utils/BasicBlockUtils.h"
>> > +#include "llvm/Transforms/Utils/ModuleUtils.h"
>> > +
>> > +using namespace llvm;
>> > +
>> > +static const uint64_t kShadowMask32 = 1ULL << 31;
>> > +static const uint64_t kShadowMask64 = 1ULL << 46;
>> > +static const uint64_t kOriginOffset32 = 1ULL << 30;
>> > +static const uint64_t kOriginOffset64 = 1ULL << 45;
>> > +
>> > +// This is an important flag that makes the reports much more
>> > +// informative at the cost of greater slowdown. Not fully implemented
>> > +// yet.
>> > +// FIXME: this should be a top-level clang flag, e.g.
>> > +// -fmemory-sanitizer-full.
>> > +static cl::opt<bool> ClTrackOrigins("msan-track-origins",
>> > + cl::desc("Track origins (allocation sites) of poisoned memory"),
>> > + cl::Hidden, cl::init(false));
>> > +static cl::opt<bool> ClKeepGoing("msan-keep-going",
>> > + cl::desc("keep going after reporting a UMR"),
>> > + cl::Hidden, cl::init(false));
>> > +static cl::opt<bool> ClPoisonStack("msan-poison-stack",
>> > + cl::desc("poison uninitialized stack variables"),
>> > + cl::Hidden, cl::init(true));
>> > +static cl::opt<bool>
>> > ClPoisonStackWithCall("msan-poison-stack-with-call",
>> > + cl::desc("poison uninitialized stack variables with a call"),
>> > + cl::Hidden, cl::init(false));
>> > +static cl::opt<int> ClPoisonStackPattern("msan-poison-stack-pattern",
>> > + cl::desc("poison uninitialized stack variables with the given
>> > patter"),
>> > + cl::Hidden, cl::init(0xff));
>> > +
>> > +static cl::opt<bool> ClHandleICmp("msan-handle-icmp",
>> > + cl::desc("propagate shadow through ICmpEQ and ICmpNE"),
>> > + cl::Hidden, cl::init(true));
>> > +
>> > +// This flag controls whether we check the shadow of the address
>> > +// operand of load or store. Such bugs are very rare, since load from
>> > +// a garbage address typically results in SEGV, but still happen
>> > +// (e.g. only lower bits of address are garbage, or the access happens
>> > +// early at program startup where malloc-ed memory is more likely to
>> > +// be zeroed. As of 2012-08-28 this flag adds 20% slowdown.
>> > +static cl::opt<bool> ClCheckAccessAddress("msan-check-access-address",
>> > + cl::desc("report accesses through a pointer which has poisoned
>> > shadow"),
>> > + cl::Hidden, cl::init(true));
>> > +
>> > +static cl::opt<bool>
>> > ClDumpStrictInstructions("msan-dump-strict-instructions",
>> > + cl::desc("print out instructions with default strict
>> > semantics"),
>> > + cl::Hidden, cl::init(false));
>> > +
>> > +static cl::opt<std::string> ClBlackListFile("msan-blacklist",
>> > + cl::desc("File containing the list of functions where
>> > MemorySanitizer "
>> > + "should not report bugs"), cl::Hidden);
>> > +
>> > +namespace {
>> > +
>> > +/// \brief An instrumentation pass implementing detection of
>> > uninitialized
>> > +/// reads.
>> > +///
>> > +/// MemorySanitizer: instrument the code in module to find
>> > +/// uninitialized reads.
>> > +class MemorySanitizer : public FunctionPass {
>> > +public:
>> > + MemorySanitizer() : FunctionPass(ID), TD(0) { }
>> > + const char *getPassName() const { return "MemorySanitizer"; }
>> > + bool runOnFunction(Function &F);
>> > + bool doInitialization(Module &M);
>> > + static char ID; // Pass identification, replacement for typeid.
>> > +
>> > +private:
>> > + DataLayout *TD;
>> > + LLVMContext *C;
>> > + Type *IntptrTy;
>> > + Type *OriginTy;
>> > + /// \brief Thread-local shadow storage for function parameters.
>> > + GlobalVariable *ParamTLS;
>> > + /// \brief Thread-local origin storage for function parameters.
>> > + GlobalVariable *ParamOriginTLS;
>> > + /// \brief Thread-local shadow storage for function return value.
>> > + GlobalVariable *RetvalTLS;
>> > + /// \brief Thread-local origin storage for function return value.
>> > + GlobalVariable *RetvalOriginTLS;
>> > + /// \brief Thread-local shadow storage for in-register va_arg
>> > function
>> > + /// parameters (x86_64-specific).
>> > + GlobalVariable *VAArgTLS;
>> > + /// \brief Thread-local shadow storage for va_arg overflow area
>> > + /// (x86_64-specific).
>> > + GlobalVariable *VAArgOverflowSizeTLS;
>> > + /// \brief Thread-local space used to pass origin value to the UMR
>> > reporting
>> > + /// function.
>> > + GlobalVariable *OriginTLS;
>> > +
>> > + /// \brief The run-time callback to print a warning.
>> > + Value *WarningFn;
>> > + /// \brief Run-time helper that copies origin info for a memory
>> > range.
>> > + Value *MsanCopyOriginFn;
>> > + /// \brief Run-time helper that generates a new origin value for a
>> > stack
>> > + /// allocation.
>> > + Value *MsanSetAllocaOriginFn;
>> > + /// \brief Run-time helper that poisons stack on function entry.
>> > + Value *MsanPoisonStackFn;
>> > + /// \brief The actual "memmove" function.
>> > + Value *MemmoveFn;
>> > +
>> > + /// \brief Address mask used in application-to-shadow address
>> > calculation.
>> > + /// ShadowAddr is computed as ApplicationAddr & ~ShadowMask.
>> > + uint64_t ShadowMask;
>> > + /// \brief Offset of the origin shadow from the "normal" shadow.
>> > + /// OriginAddr is computed as (ShadowAddr + OriginOffset) & ~3ULL
>> > + uint64_t OriginOffset;
>> > + /// \brief Branch weights for error reporting.
>> > + MDNode *ColdCallWeights;
>> > + /// \brief The blacklist.
>> > + OwningPtr<BlackList> BL;
>> > +
>> > + friend class MemorySanitizerVisitor;
>> > + friend class VarArgAMD64Helper;
>> > +};
>> > +} // namespace
>> > +
>> > +char MemorySanitizer::ID = 0;
>> > +INITIALIZE_PASS(MemorySanitizer, "msan",
>> > + "MemorySanitizer: detects uninitialized reads.",
>> > + false, false)
>> > +
>> > +FunctionPass *llvm::createMemorySanitizerPass() {
>> > + return new MemorySanitizer();
>> > +}
>> > +
>> > +/// \brief Create a non-const global initialized with the given string.
>> > +///
>> > +/// Creates a writable global for Str so that we can pass it to the
>> > +/// run-time lib. Runtime uses first 4 bytes of the string to store the
>> > +/// frame ID, so the string needs to be mutable.
>> > +static GlobalVariable *createPrivateNonConstGlobalForString(Module &M,
>> > + StringRef
>> > Str) {
>> > + Constant *StrConst = ConstantDataArray::getString(M.getContext(),
>> > Str);
>> > + return new GlobalVariable(M, StrConst->getType(),
>> > /*isConstant=*/false,
>> > + GlobalValue::PrivateLinkage, StrConst, "");
>> > +}
>> > +
>> > +/// \brief Module-level initialization.
>> > +///
>> > +/// Obtains pointers to the required runtime library functions, and
>> > +/// inserts a call to __msan_init to the module's constructor list.
>> > +bool MemorySanitizer::doInitialization(Module &M) {
>> > + TD = getAnalysisIfAvailable<DataLayout>();
>> > + if (!TD)
>> > + return false;
>> > + BL.reset(new BlackList(ClBlackListFile));
>> > + C = &(M.getContext());
>> > + unsigned PtrSize = TD->getPointerSizeInBits(/* AddressSpace */0);
>> > + switch (PtrSize) {
>> > + case 64:
>> > + ShadowMask = kShadowMask64;
>> > + OriginOffset = kOriginOffset64;
>> > + break;
>> > + case 32:
>> > + ShadowMask = kShadowMask32;
>> > + OriginOffset = kOriginOffset32;
>> > + break;
>> > + default:
>> > + report_fatal_error("unsupported pointer size");
>> > + break;
>> > + }
>> > +
>> > + IRBuilder<> IRB(*C);
>> > + IntptrTy = IRB.getIntPtrTy(TD);
>> > + OriginTy = IRB.getInt32Ty();
>> > +
>> > + ColdCallWeights = MDBuilder(*C).createBranchWeights(1, 1000);
>> > +
>> > + // Insert a call to __msan_init/__msan_track_origins into the
>> > module's CTORs.
>> > + appendToGlobalCtors(M, cast<Function>(M.getOrInsertFunction(
>> > + "__msan_init", IRB.getVoidTy(), NULL)), 0);
>> > +
>> > + new GlobalVariable(M, IRB.getInt32Ty(), true,
>> > GlobalValue::LinkOnceODRLinkage,
>> > + IRB.getInt32(ClTrackOrigins),
>> > "__msan_track_origins");
>> > +
>> > + // Create the callback.
>> > + // FIXME: this function should have "Cold" calling conv,
>> > + // which is not yet implemented.
>> > + StringRef WarningFnName = ClKeepGoing ? "__msan_warning"
>> > + : "__msan_warning_noreturn";
>> > + WarningFn = M.getOrInsertFunction(WarningFnName, IRB.getVoidTy(),
>> > NULL);
>> > +
>> > + MsanCopyOriginFn = M.getOrInsertFunction(
>> > + "__msan_copy_origin", IRB.getVoidTy(), IRB.getInt8PtrTy(),
>> > + IRB.getInt8PtrTy(), IntptrTy, NULL);
>> > + MsanSetAllocaOriginFn = M.getOrInsertFunction(
>> > + "__msan_set_alloca_origin", IRB.getVoidTy(), IRB.getInt8PtrTy(),
>> > IntptrTy,
>> > + IRB.getInt8PtrTy(), NULL);
>> > + MsanPoisonStackFn = M.getOrInsertFunction(
>> > + "__msan_poison_stack", IRB.getVoidTy(), IRB.getInt8PtrTy(),
>> > IntptrTy, NULL);
>> > + MemmoveFn = M.getOrInsertFunction(
>> > + "memmove", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
>> > IRB.getInt8PtrTy(),
>> > + IntptrTy, NULL);
>> > +
>> > + // Create globals.
>> > + RetvalTLS = new GlobalVariable(
>> > + M, ArrayType::get(IRB.getInt64Ty(), 8), false,
>> > + GlobalVariable::ExternalLinkage, 0, "__msan_retval_tls", 0,
>> > + GlobalVariable::GeneralDynamicTLSModel);
>> > + RetvalOriginTLS = new GlobalVariable(
>> > + M, OriginTy, false, GlobalVariable::ExternalLinkage, 0,
>> > + "__msan_retval_origin_tls", 0,
>> > GlobalVariable::GeneralDynamicTLSModel);
>> > +
>> > + ParamTLS = new GlobalVariable(
>> > + M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
>> > + GlobalVariable::ExternalLinkage, 0, "__msan_param_tls", 0,
>> > + GlobalVariable::GeneralDynamicTLSModel);
>> > + ParamOriginTLS = new GlobalVariable(
>> > + M, ArrayType::get(OriginTy, 1000), false,
>> > GlobalVariable::ExternalLinkage,
>> > + 0, "__msan_param_origin_tls", 0,
>> > GlobalVariable::GeneralDynamicTLSModel);
>> > +
>> > + VAArgTLS = new GlobalVariable(
>> > + M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
>> > + GlobalVariable::ExternalLinkage, 0, "__msan_va_arg_tls", 0,
>> > + GlobalVariable::GeneralDynamicTLSModel);
>> > + VAArgOverflowSizeTLS = new GlobalVariable(
>> > + M, IRB.getInt64Ty(), false, GlobalVariable::ExternalLinkage, 0,
>> > + "__msan_va_arg_overflow_size_tls", 0,
>> > + GlobalVariable::GeneralDynamicTLSModel);
>> > + OriginTLS = new GlobalVariable(
>> > + M, IRB.getInt32Ty(), false, GlobalVariable::ExternalLinkage, 0,
>> > + "__msan_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel);
>> > + return true;
>> > +}
>> > +
>> > +namespace {
>> > +
>> > +/// \brief A helper class that handles instrumentation of VarArg
>> > +/// functions on a particular platform.
>> > +///
>> > +/// Implementations are expected to insert the instrumentation
>> > +/// necessary to propagate argument shadow through VarArg function
>> > +/// calls. Visit* methods are called during an InstVisitor pass over
>> > +/// the function, and should avoid creating new basic blocks. A new
>> > +/// instance of this class is created for each instrumented function.
>> > +struct VarArgHelper {
>> > + /// \brief Visit a CallSite.
>> > + virtual void visitCallSite(CallSite &CS, IRBuilder<> &IRB) = 0;
>> > +
>> > + /// \brief Visit a va_start call.
>> > + virtual void visitVAStartInst(VAStartInst &I) = 0;
>> > +
>> > + /// \brief Visit a va_copy call.
>> > + virtual void visitVACopyInst(VACopyInst &I) = 0;
>> > +
>> > + /// \brief Finalize function instrumentation.
>> > + ///
>> > + /// This method is called after visiting all interesting (see above)
>> > + /// instructions in a function.
>> > + virtual void finalizeInstrumentation() = 0;
>> > +};
>> > +
>> > +struct MemorySanitizerVisitor;
>> > +
>> > +VarArgHelper*
>> > +CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
>> > + MemorySanitizerVisitor &Visitor);
>> > +
>> > +/// This class does all the work for a given function. Store and Load
>> > +/// instructions store and load corresponding shadow and origin
>> > +/// values. Most instructions propagate shadow from arguments to their
>> > +/// return values. Certain instructions (most importantly, BranchInst)
>> > +/// test their argument shadow and print reports (with a runtime call)
>> > if it's
>> > +/// non-zero.
>> > +struct MemorySanitizerVisitor : public
>> > InstVisitor<MemorySanitizerVisitor> {
>> > + Function &F;
>> > + MemorySanitizer &MS;
>> > + SmallVector<PHINode *, 16> ShadowPHINodes, OriginPHINodes;
>> > + ValueMap<Value*, Value*> ShadowMap, OriginMap;
>> > + bool InsertChecks;
>> > + OwningPtr<VarArgHelper> VAHelper;
>> > +
>> > + // An unfortunate workaround for asymmetric lowering of va_arg stuff.
>> > + // See a comment in visitCallSite for more details.
>> > + static const unsigned AMD64GpEndOffset = 48; // AMD64 ABI Draft
>> > 0.99.6 p3.5.7
>> > + static const unsigned AMD64FpEndOffset = 176;
>> > +
>> > + struct ShadowOriginAndInsertPoint {
>> > + Instruction *Shadow;
>> > + Instruction *Origin;
>> > + Instruction *OrigIns;
>> > + ShadowOriginAndInsertPoint(Instruction *S, Instruction *O,
>> > Instruction *I)
>> > + : Shadow(S), Origin(O), OrigIns(I) { }
>> > + ShadowOriginAndInsertPoint() : Shadow(0), Origin(0), OrigIns(0) { }
>> > + };
>> > + SmallVector<ShadowOriginAndInsertPoint, 16> InstrumentationList;
>> > +
>> > + MemorySanitizerVisitor(Function &F, MemorySanitizer &MS)
>> > + : F(F), MS(MS), VAHelper(CreateVarArgHelper(F, MS, *this)) {
>> > + InsertChecks = !MS.BL->isIn(F);
>> > + DEBUG(if (!InsertChecks)
>> > + dbgs() << "MemorySanitizer is not inserting checks into '"
>> > + << F.getName() << "'\n");
>> > + }
>> > +
>> > + void materializeChecks() {
>> > + for (size_t i = 0, n = InstrumentationList.size(); i < n; i++) {
>> > + Instruction *Shadow = InstrumentationList[i].Shadow;
>> > + Instruction *OrigIns = InstrumentationList[i].OrigIns;
>> > + IRBuilder<> IRB(OrigIns);
>> > + DEBUG(dbgs() << " SHAD0 : " << *Shadow << "\n");
>> > + Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
>> > + DEBUG(dbgs() << " SHAD1 : " << *ConvertedShadow << "\n");
>> > + Value *Cmp = IRB.CreateICmpNE(ConvertedShadow,
>> > + getCleanShadow(ConvertedShadow),
>> > "_mscmp");
>> > + Instruction *CheckTerm =
>> > + SplitBlockAndInsertIfThen(cast<Instruction>(Cmp),
>> > + /* Unreachable */ !ClKeepGoing,
>> > + MS.ColdCallWeights);
>> > +
>> > + IRB.SetInsertPoint(CheckTerm);
>> > + if (ClTrackOrigins) {
>> > + Instruction *Origin = InstrumentationList[i].Origin;
>> > + IRB.CreateStore(Origin ? (Value*)Origin :
>> > (Value*)IRB.getInt32(0),
>> > + MS.OriginTLS);
>> > + }
>> > + CallInst *Call = IRB.CreateCall(MS.WarningFn);
>> > + Call->setDebugLoc(OrigIns->getDebugLoc());
>> > + DEBUG(dbgs() << " CHECK: " << *Cmp << "\n");
>> > + }
>> > + DEBUG(dbgs() << "DONE:\n" << F);
>> > + }
>> > +
>> > + /// \brief Add MemorySanitizer instrumentation to a function.
>> > + bool runOnFunction() {
>> > + if (!MS.TD) return false;
>> > + // Iterate all BBs in depth-first order and create shadow
>> > instructions
>> > + // for all instructions (where applicable).
>> > + // For PHI nodes we create dummy shadow PHIs which will be
>> > finalized later.
>> > + for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
>> > + DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) {
>> > + BasicBlock *BB = *DI;
>> > + visit(*BB);
>> > + }
>> > +
>> > + // Finalize PHI nodes.
>> > + for (size_t i = 0, n = ShadowPHINodes.size(); i < n; i++) {
>> > + PHINode *PN = ShadowPHINodes[i];
>> > + PHINode *PNS = cast<PHINode>(getShadow(PN));
>> > + PHINode *PNO = ClTrackOrigins ? cast<PHINode>(getOrigin(PN)) : 0;
>> > + size_t NumValues = PN->getNumIncomingValues();
>> > + for (size_t v = 0; v < NumValues; v++) {
>> > + PNS->addIncoming(getShadow(PN, v), PN->getIncomingBlock(v));
>> > + if (PNO)
>> > + PNO->addIncoming(getOrigin(PN, v), PN->getIncomingBlock(v));
>> > + }
>> > + }
>> > +
>> > + VAHelper->finalizeInstrumentation();
>> > +
>> > + materializeChecks();
>> > +
>> > + return true;
>> > + }
>> > +
>> > + /// \brief Compute the shadow type that corresponds to a given Value.
>> > + Type *getShadowTy(Value *V) {
>> > + return getShadowTy(V->getType());
>> > + }
>> > +
>> > + /// \brief Compute the shadow type that corresponds to a given Type.
>> > + Type *getShadowTy(Type *OrigTy) {
>> > + if (!OrigTy->isSized()) {
>> > + return 0;
>> > + }
>> > + // For integer type, shadow is the same as the original type.
>> > + // This may return weird-sized types like i1.
>> > + if (IntegerType *IT = dyn_cast<IntegerType>(OrigTy))
>> > + return IT;
>> > + if (VectorType *VT = dyn_cast<VectorType>(OrigTy))
>> > + return VectorType::getInteger(VT);
>> > + if (StructType *ST = dyn_cast<StructType>(OrigTy)) {
>> > + SmallVector<Type*, 4> Elements;
>> > + for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
>> > + Elements.push_back(getShadowTy(ST->getElementType(i)));
>> > + StructType *Res = StructType::get(*MS.C, Elements,
>> > ST->isPacked());
>> > + DEBUG(dbgs() << "getShadowTy: " << *ST << " ===> " << *Res <<
>> > "\n");
>> > + return Res;
>> > + }
>> > + uint32_t TypeSize = MS.TD->getTypeStoreSizeInBits(OrigTy);
>> > + return IntegerType::get(*MS.C, TypeSize);
>> > + }
>> > +
>> > + /// \brief Flatten a vector type.
>> > + Type *getShadowTyNoVec(Type *ty) {
>> > + if (VectorType *vt = dyn_cast<VectorType>(ty))
>> > + return IntegerType::get(*MS.C, vt->getBitWidth());
>> > + return ty;
>> > + }
>> > +
>> > + /// \brief Convert a shadow value to it's flattened variant.
>> > + Value *convertToShadowTyNoVec(Value *V, IRBuilder<> &IRB) {
>> > + Type *Ty = V->getType();
>> > + Type *NoVecTy = getShadowTyNoVec(Ty);
>> > + if (Ty == NoVecTy) return V;
>> > + return IRB.CreateBitCast(V, NoVecTy);
>> > + }
>> > +
>> > + /// \brief Compute the shadow address that corresponds to a given
>> > application
>> > + /// address.
>> > + ///
>> > + /// Shadow = Addr & ~ShadowMask.
>> > + Value *getShadowPtr(Value *Addr, Type *ShadowTy,
>> > + IRBuilder<> &IRB) {
>> > + Value *ShadowLong =
>> > + IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
>> > + ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask));
>> > + return IRB.CreateIntToPtr(ShadowLong, PointerType::get(ShadowTy,
>> > 0));
>> > + }
>> > +
>> > + /// \brief Compute the origin address that corresponds to a given
>> > application
>> > + /// address.
>> > + ///
>> > + /// OriginAddr = (ShadowAddr + OriginOffset) & ~3ULL
>> > + /// = Addr & (~ShadowMask & ~3ULL) + OriginOffset
>> > + Value *getOriginPtr(Value *Addr, IRBuilder<> &IRB) {
>> > + Value *ShadowLong =
>> > + IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
>> > + ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask &
>> > ~3ULL));
>> > + Value *Add =
>> > + IRB.CreateAdd(ShadowLong,
>> > + ConstantInt::get(MS.IntptrTy, MS.OriginOffset));
>> > + return IRB.CreateIntToPtr(Add, PointerType::get(IRB.getInt32Ty(),
>> > 0));
>> > + }
>> > +
>> > + /// \brief Compute the shadow address for a given function argument.
>> > + ///
>> > + /// Shadow = ParamTLS+ArgOffset.
>> > + Value *getShadowPtrForArgument(Value *A, IRBuilder<> &IRB,
>> > + int ArgOffset) {
>> > + Value *Base = IRB.CreatePointerCast(MS.ParamTLS, MS.IntptrTy);
>> > + Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy,
>> > ArgOffset));
>> > + return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A),
>> > 0),
>> > + "_msarg");
>> > + }
>> > +
>> > + /// \brief Compute the origin address for a given function argument.
>> > + Value *getOriginPtrForArgument(Value *A, IRBuilder<> &IRB,
>> > + int ArgOffset) {
>> > + if (!ClTrackOrigins) return 0;
>> > + Value *Base = IRB.CreatePointerCast(MS.ParamOriginTLS,
>> > MS.IntptrTy);
>> > + Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy,
>> > ArgOffset));
>> > + return IRB.CreateIntToPtr(Base, PointerType::get(MS.OriginTy, 0),
>> > + "_msarg_o");
>> > + }
>> > +
>> > + /// \brief Compute the shadow address for a retval.
>> > + Value *getShadowPtrForRetval(Value *A, IRBuilder<> &IRB) {
>> > + Value *Base = IRB.CreatePointerCast(MS.RetvalTLS, MS.IntptrTy);
>> > + return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A),
>> > 0),
>> > + "_msret");
>> > + }
>> > +
>> > + /// \brief Compute the origin address for a retval.
>> > + Value *getOriginPtrForRetval(IRBuilder<> &IRB) {
>> > + // We keep a single origin for the entire retval. Might be too
>> > optimistic.
>> > + return MS.RetvalOriginTLS;
>> > + }
>> > +
>> > + /// \brief Set SV to be the shadow value for V.
>> > + void setShadow(Value *V, Value *SV) {
>> > + assert(!ShadowMap.count(V) && "Values may only have one shadow");
>> > + ShadowMap[V] = SV;
>> > + }
>> > +
>> > + /// \brief Set Origin to be the origin value for V.
>> > + void setOrigin(Value *V, Value *Origin) {
>> > + if (!ClTrackOrigins) return;
>> > + assert(!OriginMap.count(V) && "Values may only have one origin");
>> > + DEBUG(dbgs() << "ORIGIN: " << *V << " ==> " << *Origin << "\n");
>> > + OriginMap[V] = Origin;
>> > + }
>> > +
>> > + /// \brief Create a clean shadow value for a given value.
>> > + ///
>> > + /// Clean shadow (all zeroes) means all bits of the value are defined
>> > + /// (initialized).
>> > + Value *getCleanShadow(Value *V) {
>> > + Type *ShadowTy = getShadowTy(V);
>> > + if (!ShadowTy)
>> > + return 0;
>> > + return Constant::getNullValue(ShadowTy);
>> > + }
>> > +
>> > + /// \brief Create a dirty shadow of a given shadow type.
>> > + Constant *getPoisonedShadow(Type *ShadowTy) {
>> > + assert(ShadowTy);
>> > + if (isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy))
>> > + return Constant::getAllOnesValue(ShadowTy);
>> > + StructType *ST = cast<StructType>(ShadowTy);
>> > + SmallVector<Constant *, 4> Vals;
>> > + for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
>> > + Vals.push_back(getPoisonedShadow(ST->getElementType(i)));
>> > + return ConstantStruct::get(ST, Vals);
>> > + }
>> > +
>> > + /// \brief Create a clean (zero) origin.
>> > + Value *getCleanOrigin() {
>> > + return Constant::getNullValue(MS.OriginTy);
>> > + }
>> > +
>> > + /// \brief Get the shadow value for a given Value.
>> > + ///
>> > + /// This function either returns the value set earlier with
>> > setShadow,
>> > + /// or extracts if from ParamTLS (for function arguments).
>> > + Value *getShadow(Value *V) {
>> > + if (Instruction *I = dyn_cast<Instruction>(V)) {
>> > + // For instructions the shadow is already stored in the map.
>> > + Value *Shadow = ShadowMap[V];
>> > + if (!Shadow) {
>> > + DEBUG(dbgs() << "No shadow: " << *V << "\n" <<
>> > *(I->getParent()));
>> > + assert(Shadow && "No shadow for a value");
>> > + }
>> > + return Shadow;
>> > + }
>> > + if (UndefValue *U = dyn_cast<UndefValue>(V)) {
>> > + Value *AllOnes = getPoisonedShadow(getShadowTy(V));
>> > + DEBUG(dbgs() << "Undef: " << *U << " ==> " << *AllOnes << "\n");
>> > + return AllOnes;
>> > + }
>> > + if (Argument *A = dyn_cast<Argument>(V)) {
>> > + // For arguments we compute the shadow on demand and store it in
>> > the map.
>> > + Value **ShadowPtr = &ShadowMap[V];
>> > + if (*ShadowPtr)
>> > + return *ShadowPtr;
>> > + Function *F = A->getParent();
>> > + IRBuilder<> EntryIRB(F->getEntryBlock().getFirstNonPHI());
>> > + unsigned ArgOffset = 0;
>> > + for (Function::arg_iterator AI = F->arg_begin(), AE =
>> > F->arg_end();
>> > + AI != AE; ++AI) {
>> > + if (!AI->getType()->isSized()) {
>> > + DEBUG(dbgs() << "Arg is not sized\n");
>> > + continue;
>> > + }
>> > + unsigned Size = AI->hasByValAttr()
>> > + ?
>> > MS.TD->getTypeAllocSize(AI->getType()->getPointerElementType())
>> > + : MS.TD->getTypeAllocSize(AI->getType());
>> > + if (A == AI) {
>> > + Value *Base = getShadowPtrForArgument(AI, EntryIRB,
>> > ArgOffset);
>> > + if (AI->hasByValAttr()) {
>> > + // ByVal pointer itself has clean shadow. We copy the
>> > actual
>> > + // argument shadow to the underlying memory.
>> > + Value *Cpy = EntryIRB.CreateMemCpy(
>> > + getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB),
>> > + Base, Size, AI->getParamAlignment());
>> > + DEBUG(dbgs() << " ByValCpy: " << *Cpy << "\n");
>> > + *ShadowPtr = getCleanShadow(V);
>> > + } else {
>> > + *ShadowPtr = EntryIRB.CreateLoad(Base);
>> > + }
>> > + DEBUG(dbgs() << " ARG: " << *AI << " ==> " <<
>> > + **ShadowPtr << "\n");
>> > + if (ClTrackOrigins) {
>> > + Value* OriginPtr = getOriginPtrForArgument(AI, EntryIRB,
>> > ArgOffset);
>> > + setOrigin(A, EntryIRB.CreateLoad(OriginPtr));
>> > + }
>> > + }
>> > + ArgOffset += DataLayout::RoundUpAlignment(Size, 8);
>> > + }
>> > + assert(*ShadowPtr && "Could not find shadow for an argument");
>> > + return *ShadowPtr;
>> > + }
>> > + // For everything else the shadow is zero.
>> > + return getCleanShadow(V);
>> > + }
>> > +
>> > + /// \brief Get the shadow for i-th argument of the instruction I.
>> > + Value *getShadow(Instruction *I, int i) {
>> > + return getShadow(I->getOperand(i));
>> > + }
>> > +
>> > + /// \brief Get the origin for a value.
>> > + Value *getOrigin(Value *V) {
>> > + if (!ClTrackOrigins) return 0;
>> > + if (isa<Instruction>(V) || isa<Argument>(V)) {
>> > + Value *Origin = OriginMap[V];
>> > + if (!Origin) {
>> > + DEBUG(dbgs() << "NO ORIGIN: " << *V << "\n");
>> > + Origin = getCleanOrigin();
>> > + }
>> > + return Origin;
>> > + }
>> > + return getCleanOrigin();
>> > + }
>> > +
>> > + /// \brief Get the origin for i-th argument of the instruction I.
>> > + Value *getOrigin(Instruction *I, int i) {
>> > + return getOrigin(I->getOperand(i));
>> > + }
>> > +
>> > + /// \brief Remember the place where a shadow check should be
>> > inserted.
>> > + ///
>> > + /// This location will be later instrumented with a check that will
>> > print a
>> > + /// UMR warning in runtime if the value is not fully defined.
>> > + void insertCheck(Value *Val, Instruction *OrigIns) {
>> > + assert(Val);
>> > + if (!InsertChecks) return;
>> > + Instruction *Shadow =
>> > dyn_cast_or_null<Instruction>(getShadow(Val));
>> > + if (!Shadow) return;
>> > + Type *ShadowTy = Shadow->getType();
>> > + assert((isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy)) &&
>> > + "Can only insert checks for integer and vector shadow
>> > types");
>> > + Instruction *Origin =
>> > dyn_cast_or_null<Instruction>(getOrigin(Val));
>> > + InstrumentationList.push_back(
>> > + ShadowOriginAndInsertPoint(Shadow, Origin, OrigIns));
>> > + }
>> > +
>> > + //------------------- Visitors.
>> > +
>> > + /// \brief Instrument LoadInst
>> > + ///
>> > + /// Loads the corresponding shadow and (optionally) origin.
>> > + /// Optionally, checks that the load address is fully defined.
>> > + void visitLoadInst(LoadInst &I) {
>> > + Type *LoadTy = I.getType();
>> > + assert(LoadTy->isSized() && "Load type must have size");
>> > + IRBuilder<> IRB(&I);
>> > + Type *ShadowTy = getShadowTy(&I);
>> > + Value *Addr = I.getPointerOperand();
>> > + Value *ShadowPtr = getShadowPtr(Addr, ShadowTy, IRB);
>> > + setShadow(&I, IRB.CreateLoad(ShadowPtr, "_msld"));
>> > +
>> > + if (ClCheckAccessAddress)
>> > + insertCheck(I.getPointerOperand(), &I);
>> > +
>> > + if (ClTrackOrigins)
>> > + setOrigin(&I, IRB.CreateLoad(getOriginPtr(Addr, IRB)));
>> > + }
>> > +
>> > + /// \brief Instrument StoreInst
>> > + ///
>> > + /// Stores the corresponding shadow and (optionally) origin.
>> > + /// Optionally, checks that the store address is fully defined.
>> > + /// Volatile stores check that the value being stored is fully
>> > defined.
>> > + void visitStoreInst(StoreInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + Value *Val = I.getValueOperand();
>> > + Value *Addr = I.getPointerOperand();
>> > + Value *Shadow = getShadow(Val);
>> > + Value *ShadowPtr = getShadowPtr(Addr, Shadow->getType(), IRB);
>> > +
>> > + StoreInst *NewSI = IRB.CreateStore(Shadow, ShadowPtr);
>> > + DEBUG(dbgs() << " STORE: " << *NewSI << "\n");
>> > + // If the store is volatile, add a check.
>> > + if (I.isVolatile())
>> > + insertCheck(Val, &I);
>> > + if (ClCheckAccessAddress)
>> > + insertCheck(Addr, &I);
>> > +
>> > + if (ClTrackOrigins)
>> > + IRB.CreateStore(getOrigin(Val), getOriginPtr(Addr, IRB));
>> > + }
>> > +
>> > + // Casts.
>> > + void visitSExtInst(SExtInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + setShadow(&I, IRB.CreateSExt(getShadow(&I, 0), I.getType(),
>> > "_msprop"));
>> > + setOrigin(&I, getOrigin(&I, 0));
>> > + }
>> > +
>> > + void visitZExtInst(ZExtInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + setShadow(&I, IRB.CreateZExt(getShadow(&I, 0), I.getType(),
>> > "_msprop"));
>> > + setOrigin(&I, getOrigin(&I, 0));
>> > + }
>> > +
>> > + void visitTruncInst(TruncInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + setShadow(&I, IRB.CreateTrunc(getShadow(&I, 0), I.getType(),
>> > "_msprop"));
>> > + setOrigin(&I, getOrigin(&I, 0));
>> > + }
>> > +
>> > + void visitBitCastInst(BitCastInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + setShadow(&I, IRB.CreateBitCast(getShadow(&I, 0),
>> > getShadowTy(&I)));
>> > + setOrigin(&I, getOrigin(&I, 0));
>> > + }
>> > +
>> > + void visitPtrToIntInst(PtrToIntInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I),
>> > false,
>> > + "_msprop_ptrtoint"));
>> > + setOrigin(&I, getOrigin(&I, 0));
>> > + }
>> > +
>> > + void visitIntToPtrInst(IntToPtrInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I),
>> > false,
>> > + "_msprop_inttoptr"));
>> > + setOrigin(&I, getOrigin(&I, 0));
>> > + }
>> > +
>> > + void visitFPToSIInst(CastInst& I) { handleShadowOr(I); }
>> > + void visitFPToUIInst(CastInst& I) { handleShadowOr(I); }
>> > + void visitSIToFPInst(CastInst& I) { handleShadowOr(I); }
>> > + void visitUIToFPInst(CastInst& I) { handleShadowOr(I); }
>> > + void visitFPExtInst(CastInst& I) { handleShadowOr(I); }
>> > + void visitFPTruncInst(CastInst& I) { handleShadowOr(I); }
>> > +
>> > + /// \brief Propagate shadow for bitwise AND.
>> > + ///
>> > + /// This code is exact, i.e. if, for example, a bit in the left
>> > argument
>> > + /// is defined and 0, then neither the value not definedness of the
>> > + /// corresponding bit in B don't affect the resulting shadow.
>> > + void visitAnd(BinaryOperator &I) {
>> > + IRBuilder<> IRB(&I);
>> > + // "And" of 0 and a poisoned value results in unpoisoned value.
>> > + // 1&1 => 1; 0&1 => 0; p&1 => p;
>> > + // 1&0 => 0; 0&0 => 0; p&0 => 0;
>> > + // 1&p => p; 0&p => 0; p&p => p;
>> > + // S = (S1 & S2) | (V1 & S2) | (S1 & V2)
>> > + Value *S1 = getShadow(&I, 0);
>> > + Value *S2 = getShadow(&I, 1);
>> > + Value *V1 = I.getOperand(0);
>> > + Value *V2 = I.getOperand(1);
>> > + if (V1->getType() != S1->getType()) {
>> > + V1 = IRB.CreateIntCast(V1, S1->getType(), false);
>> > + V2 = IRB.CreateIntCast(V2, S2->getType(), false);
>> > + }
>> > + Value *S1S2 = IRB.CreateAnd(S1, S2);
>> > + Value *V1S2 = IRB.CreateAnd(V1, S2);
>> > + Value *S1V2 = IRB.CreateAnd(S1, V2);
>> > + setShadow(&I, IRB.CreateOr(S1S2, IRB.CreateOr(V1S2, S1V2)));
>> > + setOriginForNaryOp(I);
>> > + }
>> > +
>> > + void visitOr(BinaryOperator &I) {
>> > + IRBuilder<> IRB(&I);
>> > + // "Or" of 1 and a poisoned value results in unpoisoned value.
>> > + // 1|1 => 1; 0|1 => 1; p|1 => 1;
>> > + // 1|0 => 1; 0|0 => 0; p|0 => p;
>> > + // 1|p => 1; 0|p => p; p|p => p;
>> > + // S = (S1 & S2) | (~V1 & S2) | (S1 & ~V2)
>> > + Value *S1 = getShadow(&I, 0);
>> > + Value *S2 = getShadow(&I, 1);
>> > + Value *V1 = IRB.CreateNot(I.getOperand(0));
>> > + Value *V2 = IRB.CreateNot(I.getOperand(1));
>> > + if (V1->getType() != S1->getType()) {
>> > + V1 = IRB.CreateIntCast(V1, S1->getType(), false);
>> > + V2 = IRB.CreateIntCast(V2, S2->getType(), false);
>> > + }
>> > + Value *S1S2 = IRB.CreateAnd(S1, S2);
>> > + Value *V1S2 = IRB.CreateAnd(V1, S2);
>> > + Value *S1V2 = IRB.CreateAnd(S1, V2);
>> > + setShadow(&I, IRB.CreateOr(S1S2, IRB.CreateOr(V1S2, S1V2)));
>> > + setOriginForNaryOp(I);
>> > + }
>> > +
>> > + /// \brief Propagate origin for an instruction.
>> > + ///
>> > + /// This is a general case of origin propagation. For an Nary
>> > operation,
>> > + /// is set to the origin of an argument that is not entirely
>> > initialized.
>> > + /// It does not matter which one is picked if all arguments are
>> > initialized.
>> > + void setOriginForNaryOp(Instruction &I) {
>> > + if (!ClTrackOrigins) return;
>> > + IRBuilder<> IRB(&I);
>> > + Value *Origin = getOrigin(&I, 0);
>> > + for (unsigned Op = 1, n = I.getNumOperands(); Op < n; ++Op) {
>> > + Value *S = convertToShadowTyNoVec(getShadow(&I, Op - 1), IRB);
>> > + Origin = IRB.CreateSelect(IRB.CreateICmpNE(S, getCleanShadow(S)),
>> > + Origin, getOrigin(&I, Op));
>> > + }
>> > + setOrigin(&I, Origin);
>> > + }
>> > +
>> > + /// \brief Propagate shadow for a binary operation.
>> > + ///
>> > + /// Shadow = Shadow0 | Shadow1, all 3 must have the same type.
>> > + /// Bitwise OR is selected as an operation that will never lose even
>> > a bit of
>> > + /// poison.
>> > + void handleShadowOrBinary(Instruction &I) {
>> > + IRBuilder<> IRB(&I);
>> > + Value *Shadow0 = getShadow(&I, 0);
>> > + Value *Shadow1 = getShadow(&I, 1);
>> > + setShadow(&I, IRB.CreateOr(Shadow0, Shadow1, "_msprop"));
>> > + setOriginForNaryOp(I);
>> > + }
>> > +
>> > + /// \brief Propagate shadow for arbitrary operation.
>> > + ///
>> > + /// This is a general case of shadow propagation, used in all cases
>> > where we
>> > + /// don't know and/or care about what the operation actually does.
>> > + /// It converts all input shadow values to a common type (extending
>> > or
>> > + /// truncating as necessary), and bitwise OR's them.
>> > + ///
>> > + /// This is much cheaper than inserting checks (i.e. requiring inputs
>> > to be
>> > + /// fully initialized), and less prone to false positives.
>> > + // FIXME: is the casting actually correct?
>> > + // FIXME: merge this with handleShadowOrBinary.
>> > + void handleShadowOr(Instruction &I) {
>> > + IRBuilder<> IRB(&I);
>> > + Value *Shadow = getShadow(&I, 0);
>> > + for (unsigned Op = 1, n = I.getNumOperands(); Op < n; ++Op)
>> > + Shadow = IRB.CreateOr(
>> > + Shadow, IRB.CreateIntCast(getShadow(&I, Op), Shadow->getType(),
>> > false),
>> > + "_msprop");
>> > + Shadow = IRB.CreateIntCast(Shadow, getShadowTy(&I), false);
>> > + setShadow(&I, Shadow);
>> > + setOriginForNaryOp(I);
>> > + }
>> > +
>> > + void visitFAdd(BinaryOperator &I) { handleShadowOrBinary(I); }
>> > + void visitFSub(BinaryOperator &I) { handleShadowOrBinary(I); }
>> > + void visitFMul(BinaryOperator &I) { handleShadowOrBinary(I); }
>> > + void visitAdd(BinaryOperator &I) { handleShadowOrBinary(I); }
>> > + void visitSub(BinaryOperator &I) { handleShadowOrBinary(I); }
>> > + void visitXor(BinaryOperator &I) { handleShadowOrBinary(I); }
>> > + void visitMul(BinaryOperator &I) { handleShadowOrBinary(I); }
>> > +
>> > + void handleDiv(Instruction &I) {
>> > + IRBuilder<> IRB(&I);
>> > + // Strict on the second argument.
>> > + insertCheck(I.getOperand(1), &I);
>> > + setShadow(&I, getShadow(&I, 0));
>> > + setOrigin(&I, getOrigin(&I, 0));
>> > + }
>> > +
>> > + void visitUDiv(BinaryOperator &I) { handleDiv(I); }
>> > + void visitSDiv(BinaryOperator &I) { handleDiv(I); }
>> > + void visitFDiv(BinaryOperator &I) { handleDiv(I); }
>> > + void visitURem(BinaryOperator &I) { handleDiv(I); }
>> > + void visitSRem(BinaryOperator &I) { handleDiv(I); }
>> > + void visitFRem(BinaryOperator &I) { handleDiv(I); }
>> > +
>> > + /// \brief Instrument == and != comparisons.
>> > + ///
>> > + /// Sometimes the comparison result is known even if some of the bits
>> > of the
>> > + /// arguments are not.
>> > + void handleEqualityComparison(ICmpInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + Value *A = I.getOperand(0);
>> > + Value *B = I.getOperand(1);
>> > + Value *Sa = getShadow(A);
>> > + Value *Sb = getShadow(B);
>> > + if (A->getType()->isPointerTy())
>> > + A = IRB.CreatePointerCast(A, MS.IntptrTy);
>> > + if (B->getType()->isPointerTy())
>> > + B = IRB.CreatePointerCast(B, MS.IntptrTy);
>> > + // A == B <==> (C = A^B) == 0
>> > + // A != B <==> (C = A^B) != 0
>> > + // Sc = Sa | Sb
>> > + Value *C = IRB.CreateXor(A, B);
>> > + Value *Sc = IRB.CreateOr(Sa, Sb);
>> > + // Now dealing with i = (C == 0) comparison (or C != 0, does not
>> > matter now)
>> > + // Result is defined if one of the following is true
>> > + // * there is a defined 1 bit in C
>> > + // * C is fully defined
>> > + // Si = !(C & ~Sc) && Sc
>> > + Value *Zero = Constant::getNullValue(Sc->getType());
>> > + Value *MinusOne = Constant::getAllOnesValue(Sc->getType());
>> > + Value *Si =
>> > + IRB.CreateAnd(IRB.CreateICmpNE(Sc, Zero),
>> > + IRB.CreateICmpEQ(
>> > + IRB.CreateAnd(IRB.CreateXor(Sc, MinusOne), C),
>> > Zero));
>> > + Si->setName("_msprop_icmp");
>> > + setShadow(&I, Si);
>> > + setOriginForNaryOp(I);
>> > + }
>> > +
>> > + void visitICmpInst(ICmpInst &I) {
>> > + if (ClHandleICmp && I.isEquality())
>> > + handleEqualityComparison(I);
>> > + else
>> > + handleShadowOr(I);
>> > + }
>> > +
>> > + void visitFCmpInst(FCmpInst &I) {
>> > + handleShadowOr(I);
>> > + }
>> > +
>> > + void handleShift(BinaryOperator &I) {
>> > + IRBuilder<> IRB(&I);
>> > + // If any of the S2 bits are poisoned, the whole thing is poisoned.
>> > + // Otherwise perform the same shift on S1.
>> > + Value *S1 = getShadow(&I, 0);
>> > + Value *S2 = getShadow(&I, 1);
>> > + Value *S2Conv = IRB.CreateSExt(IRB.CreateICmpNE(S2,
>> > getCleanShadow(S2)),
>> > + S2->getType());
>> > + Value *V2 = I.getOperand(1);
>> > + Value *Shift = IRB.CreateBinOp(I.getOpcode(), S1, V2);
>> > + setShadow(&I, IRB.CreateOr(Shift, S2Conv));
>> > + setOriginForNaryOp(I);
>> > + }
>> > +
>> > + void visitShl(BinaryOperator &I) { handleShift(I); }
>> > + void visitAShr(BinaryOperator &I) { handleShift(I); }
>> > + void visitLShr(BinaryOperator &I) { handleShift(I); }
>> > +
>> > + void visitMemSetInst(MemSetInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + Value *Ptr = I.getArgOperand(0);
>> > + Value *Val = I.getArgOperand(1);
>> > + Value *ShadowPtr = getShadowPtr(Ptr, Val->getType(), IRB);
>> > + Value *ShadowVal = getCleanShadow(Val);
>> > + Value *Size = I.getArgOperand(2);
>> > + unsigned Align = I.getAlignment();
>> > + bool isVolatile = I.isVolatile();
>> > +
>> > + IRB.CreateMemSet(ShadowPtr, ShadowVal, Size, Align, isVolatile);
>> > + }
>> > +
>> > + void visitMemCpyInst(MemCpyInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + Value *Dst = I.getArgOperand(0);
>> > + Value *Src = I.getArgOperand(1);
>> > + Type *ElementType =
>> > dyn_cast<PointerType>(Dst->getType())->getElementType();
>> > + Value *ShadowDst = getShadowPtr(Dst, ElementType, IRB);
>> > + Value *ShadowSrc = getShadowPtr(Src, ElementType, IRB);
>> > + Value *Size = I.getArgOperand(2);
>> > + unsigned Align = I.getAlignment();
>> > + bool isVolatile = I.isVolatile();
>> > +
>> > + IRB.CreateMemCpy(ShadowDst, ShadowSrc, Size, Align, isVolatile);
>> > + if (ClTrackOrigins)
>> > + IRB.CreateCall3(MS.MsanCopyOriginFn, Dst, Src, Size);
>> > + }
>> > +
>> > + /// \brief Instrument llvm.memmove
>> > + ///
>> > + /// At this point we don't know if llvm.memmove will be inlined or
>> > not.
>> > + /// If we don't instrument it and it gets inlined,
>> > + /// our interceptor will not kick in and we will lose the memmove.
>> > + /// If we instrument the call here, but it does not get inlined,
>> > + /// we will memove the shadow twice: which is bad in case
>> > + /// of overlapping regions. So, we simply lower the intrinsic to a
>> > call.
>> > + ///
>> > + /// Similar situation exists for memcpy and memset, but for those
>> > functions
>> > + /// calling instrumentation twice does not lead to incorrect results.
>> > + void visitMemMoveInst(MemMoveInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + IRB.CreateCall3(
>> > + MS.MemmoveFn,
>> > + IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
>> > + IRB.CreatePointerCast(I.getArgOperand(1), IRB.getInt8PtrTy()),
>> > + IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false));
>> > + I.eraseFromParent();
>> > + }
>> > +
>> > + void visitVAStartInst(VAStartInst &I) {
>> > + VAHelper->visitVAStartInst(I);
>> > + }
>> > +
>> > + void visitVACopyInst(VACopyInst &I) {
>> > + VAHelper->visitVACopyInst(I);
>> > + }
>> > +
>> > + void visitCallSite(CallSite CS) {
>> > + Instruction &I = *CS.getInstruction();
>> > + assert((CS.isCall() || CS.isInvoke()) && "Unknown type of
>> > CallSite");
>> > + if (CS.isCall()) {
>> > + // Allow only tail calls with the same types, otherwise
>> > + // we may have a false positive: shadow for a non-void RetVal
>> > + // will get propagated to a void RetVal.
>> > + CallInst *Call = cast<CallInst>(&I);
>> > + if (Call->isTailCall() && Call->getType() !=
>> > Call->getParent()->getType())
>> > + Call->setTailCall(false);
>> > + if (isa<IntrinsicInst>(&I)) {
>> > + // All intrinsics we care about are handled in corresponding
>> > visit*
>> > + // methods. Add checks for the arguments, mark retval as clean.
>> > + visitInstruction(I);
>> > + return;
>> > + }
>> > + }
>> > + IRBuilder<> IRB(&I);
>> > + unsigned ArgOffset = 0;
>> > + DEBUG(dbgs() << " CallSite: " << I << "\n");
>> > + for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End =
>> > CS.arg_end();
>> > + ArgIt != End; ++ArgIt) {
>> > + Value *A = *ArgIt;
>> > + unsigned i = ArgIt - CS.arg_begin();
>> > + if (!A->getType()->isSized()) {
>> > + DEBUG(dbgs() << "Arg " << i << " is not sized: " << I << "\n");
>> > + continue;
>> > + }
>> > + unsigned Size = 0;
>> > + Value *Store = 0;
>> > + // Compute the Shadow for arg even if it is ByVal, because
>> > + // in that case getShadow() will copy the actual arg shadow to
>> > + // __msan_param_tls.
>> > + Value *ArgShadow = getShadow(A);
>> > + Value *ArgShadowBase = getShadowPtrForArgument(A, IRB,
>> > ArgOffset);
>> > + DEBUG(dbgs() << " Arg#" << i << ": " << *A <<
>> > + " Shadow: " << *ArgShadow << "\n");
>> > + if (CS.paramHasAttr(i + 1, Attributes::ByVal)) {
>> > + assert(A->getType()->isPointerTy() &&
>> > + "ByVal argument is not a pointer!");
>> > + Size =
>> > MS.TD->getTypeAllocSize(A->getType()->getPointerElementType());
>> > + unsigned Alignment = CS.getParamAlignment(i + 1);
>> > + Store = IRB.CreateMemCpy(ArgShadowBase,
>> > + getShadowPtr(A,
>> > Type::getInt8Ty(*MS.C), IRB),
>> > + Size, Alignment);
>> > + } else {
>> > + Size = MS.TD->getTypeAllocSize(A->getType());
>> > + Store = IRB.CreateStore(ArgShadow, ArgShadowBase);
>> > + }
>> > + if (ClTrackOrigins)
>> > + IRB.CreateStore(getOrigin(A),
>> > + getOriginPtrForArgument(A, IRB, ArgOffset));
>> > + assert(Size != 0 && Store != 0);
>> > + DEBUG(dbgs() << " Param:" << *Store << "\n");
>> > + ArgOffset += DataLayout::RoundUpAlignment(Size, 8);
>> > + }
>> > + DEBUG(dbgs() << " done with call args\n");
>> > +
>> > + FunctionType *FT =
>> > + cast<FunctionType>(CS.getCalledValue()->getType()->
>> > getContainedType(0));
>> > + if (FT->isVarArg()) {
>> > + VAHelper->visitCallSite(CS, IRB);
>> > + }
>> > +
>> > + // Now, get the shadow for the RetVal.
>> > + if (!I.getType()->isSized()) return;
>> > + IRBuilder<> IRBBefore(&I);
>> > + // Untill we have full dynamic coverage, make sure the retval
>> > shadow is 0.
>> > + Value *Base = getShadowPtrForRetval(&I, IRBBefore);
>> > + IRBBefore.CreateStore(getCleanShadow(&I), Base);
>> > + Instruction *NextInsn = 0;
>> > + if (CS.isCall()) {
>> > + NextInsn = I.getNextNode();
>> > + } else {
>> > + BasicBlock *NormalDest = cast<InvokeInst>(&I)->getNormalDest();
>> > + if (!NormalDest->getSinglePredecessor()) {
>> > + // FIXME: this case is tricky, so we are just conservative
>> > here.
>> > + // Perhaps we need to split the edge between this BB and
>> > NormalDest,
>> > + // but a naive attempt to use SplitEdge leads to a crash.
>> > + setShadow(&I, getCleanShadow(&I));
>> > + setOrigin(&I, getCleanOrigin());
>> > + return;
>> > + }
>> > + NextInsn = NormalDest->getFirstInsertionPt();
>> > + assert(NextInsn &&
>> > + "Could not find insertion point for retval shadow load");
>> > + }
>> > + IRBuilder<> IRBAfter(NextInsn);
>> > + setShadow(&I, IRBAfter.CreateLoad(getShadowPtrForRetval(&I,
>> > IRBAfter),
>> > + "_msret"));
>> > + if (ClTrackOrigins)
>> > + setOrigin(&I,
>> > IRBAfter.CreateLoad(getOriginPtrForRetval(IRBAfter)));
>> > + }
>> > +
>> > + void visitReturnInst(ReturnInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + if (Value *RetVal = I.getReturnValue()) {
>> > + // Set the shadow for the RetVal.
>> > + Value *Shadow = getShadow(RetVal);
>> > + Value *ShadowPtr = getShadowPtrForRetval(RetVal, IRB);
>> > + DEBUG(dbgs() << "Return: " << *Shadow << "\n" << *ShadowPtr <<
>> > "\n");
>> > + IRB.CreateStore(Shadow, ShadowPtr);
>> > + if (ClTrackOrigins)
>> > + IRB.CreateStore(getOrigin(RetVal), getOriginPtrForRetval(IRB));
>> > + }
>> > + }
>> > +
>> > + void visitPHINode(PHINode &I) {
>> > + IRBuilder<> IRB(&I);
>> > + ShadowPHINodes.push_back(&I);
>> > + setShadow(&I, IRB.CreatePHI(getShadowTy(&I),
>> > I.getNumIncomingValues(),
>> > + "_msphi_s"));
>> > + if (ClTrackOrigins)
>> > + setOrigin(&I, IRB.CreatePHI(MS.OriginTy,
>> > I.getNumIncomingValues(),
>> > + "_msphi_o"));
>> > + }
>> > +
>> > + void visitAllocaInst(AllocaInst &I) {
>> > + setShadow(&I, getCleanShadow(&I));
>> > + if (!ClPoisonStack) return;
>> > + IRBuilder<> IRB(I.getNextNode());
>> > + uint64_t Size = MS.TD->getTypeAllocSize(I.getAllocatedType());
>> > + if (ClPoisonStackWithCall) {
>> > + IRB.CreateCall2(MS.MsanPoisonStackFn,
>> > + IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()),
>> > + ConstantInt::get(MS.IntptrTy, Size));
>> > + } else {
>> > + Value *ShadowBase = getShadowPtr(&I, Type::getInt8PtrTy(*MS.C),
>> > IRB);
>> > + IRB.CreateMemSet(ShadowBase, IRB.getInt8(ClPoisonStackPattern),
>> > + Size, I.getAlignment());
>> > + }
>> > +
>> > + if (ClTrackOrigins) {
>> > + setOrigin(&I, getCleanOrigin());
>> > + SmallString<2048> StackDescriptionStorage;
>> > + raw_svector_ostream StackDescription(StackDescriptionStorage);
>> > + // We create a string with a description of the stack allocation
>> > and
>> > + // pass it into __msan_set_alloca_origin.
>> > + // It will be printed by the run-time if stack-originated UMR is
>> > found.
>> > + // The first 4 bytes of the string are set to '----' and will be
>> > replaced
>> > + // by __msan_va_arg_overflow_size_tls at the first call.
>> > + StackDescription << "----" << I.getName() << "@" << F.getName();
>> > + Value *Descr =
>> > + createPrivateNonConstGlobalForString(*F.getParent(),
>> > + StackDescription.str());
>> > + IRB.CreateCall3(MS.MsanSetAllocaOriginFn,
>> > + IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()),
>> > + ConstantInt::get(MS.IntptrTy, Size),
>> > + IRB.CreatePointerCast(Descr,
>> > IRB.getInt8PtrTy()));
>> > + }
>> > + }
>> > +
>> > + void visitSelectInst(SelectInst& I) {
>> > + IRBuilder<> IRB(&I);
>> > + setShadow(&I, IRB.CreateSelect(I.getCondition(),
>> > + getShadow(I.getTrueValue()),
>> > getShadow(I.getFalseValue()),
>> > + "_msprop"));
>> > + if (ClTrackOrigins)
>> > + setOrigin(&I, IRB.CreateSelect(I.getCondition(),
>> > + getOrigin(I.getTrueValue()),
>> > getOrigin(I.getFalseValue())));
>> > + }
>> > +
>> > + void visitLandingPadInst(LandingPadInst &I) {
>> > + // Do nothing.
>> > + // See http://code.google.com/p/memory-sanitizer/issues/detail?id=1
>> > + setShadow(&I, getCleanShadow(&I));
>> > + setOrigin(&I, getCleanOrigin());
>> > + }
>> > +
>> > + void visitGetElementPtrInst(GetElementPtrInst &I) {
>> > + handleShadowOr(I);
>> > + }
>> > +
>> > + void visitExtractValueInst(ExtractValueInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + Value *Agg = I.getAggregateOperand();
>> > + DEBUG(dbgs() << "ExtractValue: " << I << "\n");
>> > + Value *AggShadow = getShadow(Agg);
>> > + DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n");
>> > + Value *ResShadow = IRB.CreateExtractValue(AggShadow,
>> > I.getIndices());
>> > + DEBUG(dbgs() << " ResShadow: " << *ResShadow << "\n");
>> > + setShadow(&I, ResShadow);
>> > + setOrigin(&I, getCleanOrigin());
>> > + }
>> > +
>> > + void visitInsertValueInst(InsertValueInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + DEBUG(dbgs() << "InsertValue: " << I << "\n");
>> > + Value *AggShadow = getShadow(I.getAggregateOperand());
>> > + Value *InsShadow = getShadow(I.getInsertedValueOperand());
>> > + DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n");
>> > + DEBUG(dbgs() << " InsShadow: " << *InsShadow << "\n");
>> > + Value *Res = IRB.CreateInsertValue(AggShadow, InsShadow,
>> > I.getIndices());
>> > + DEBUG(dbgs() << " Res: " << *Res << "\n");
>> > + setShadow(&I, Res);
>> > + setOrigin(&I, getCleanOrigin());
>> > + }
>> > +
>> > + void dumpInst(Instruction &I) {
>> > + if (CallInst *CI = dyn_cast<CallInst>(&I)) {
>> > + errs() << "ZZZ call " << CI->getCalledFunction()->getName() <<
>> > "\n";
>> > + } else {
>> > + errs() << "ZZZ " << I.getOpcodeName() << "\n";
>> > + }
>> > + errs() << "QQQ " << I << "\n";
>> > + }
>> > +
>> > + void visitResumeInst(ResumeInst &I) {
>> > + DEBUG(dbgs() << "Resume: " << I << "\n");
>> > + // Nothing to do here.
>> > + }
>> > +
>> > + void visitInstruction(Instruction &I) {
>> > + // Everything else: stop propagating and check for poisoned shadow.
>> > + if (ClDumpStrictInstructions)
>> > + dumpInst(I);
>> > + DEBUG(dbgs() << "DEFAULT: " << I << "\n");
>> > + for (size_t i = 0, n = I.getNumOperands(); i < n; i++)
>> > + insertCheck(I.getOperand(i), &I);
>> > + setShadow(&I, getCleanShadow(&I));
>> > + setOrigin(&I, getCleanOrigin());
>> > + }
>> > +};
>> > +
>> > +/// \brief AMD64-specific implementation of VarArgHelper.
>> > +struct VarArgAMD64Helper : public VarArgHelper {
>> > + // An unfortunate workaround for asymmetric lowering of va_arg stuff.
>> > + // See a comment in visitCallSite for more details.
>> > + static const unsigned AMD64GpEndOffset = 48; // AMD64 ABI Draft
>> > 0.99.6 p3.5.7
>> > + static const unsigned AMD64FpEndOffset = 176;
>> > +
>> > + Function &F;
>> > + MemorySanitizer &MS;
>> > + MemorySanitizerVisitor &MSV;
>> > + Value *VAArgTLSCopy;
>> > + Value *VAArgOverflowSize;
>> > +
>> > + SmallVector<CallInst*, 16> VAStartInstrumentationList;
>> > +
>> > + VarArgAMD64Helper(Function &F, MemorySanitizer &MS,
>> > + MemorySanitizerVisitor &MSV)
>> > + : F(F), MS(MS), MSV(MSV), VAArgTLSCopy(0), VAArgOverflowSize(0) { }
>> > +
>> > + enum ArgKind { AK_GeneralPurpose, AK_FloatingPoint, AK_Memory };
>> > +
>> > + ArgKind classifyArgument(Value* arg) {
>> > + // A very rough approximation of X86_64 argument classification
>> > rules.
>> > + Type *T = arg->getType();
>> > + if (T->isFPOrFPVectorTy() || T->isX86_MMXTy())
>> > + return AK_FloatingPoint;
>> > + if (T->isIntegerTy() && T->getPrimitiveSizeInBits() <= 64)
>> > + return AK_GeneralPurpose;
>> > + if (T->isPointerTy())
>> > + return AK_GeneralPurpose;
>> > + return AK_Memory;
>> > + }
>> > +
>> > + // For VarArg functions, store the argument shadow in an ABI-specific
>> > format
>> > + // that corresponds to va_list layout.
>> > + // We do this because Clang lowers va_arg in the frontend, and this
>> > pass
>> > + // only sees the low level code that deals with va_list internals.
>> > + // A much easier alternative (provided that Clang emits va_arg
>> > instructions)
>> > + // would have been to associate each live instance of va_list with a
>> > copy of
>> > + // MSanParamTLS, and extract shadow on va_arg() call in the argument
>> > list
>> > + // order.
>> > + void visitCallSite(CallSite &CS, IRBuilder<> &IRB) {
>> > + unsigned GpOffset = 0;
>> > + unsigned FpOffset = AMD64GpEndOffset;
>> > + unsigned OverflowOffset = AMD64FpEndOffset;
>> > + for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End =
>> > CS.arg_end();
>> > + ArgIt != End; ++ArgIt) {
>> > + Value *A = *ArgIt;
>> > + ArgKind AK = classifyArgument(A);
>> > + if (AK == AK_GeneralPurpose && GpOffset >= AMD64GpEndOffset)
>> > + AK = AK_Memory;
>> > + if (AK == AK_FloatingPoint && FpOffset >= AMD64FpEndOffset)
>> > + AK = AK_Memory;
>> > + Value *Base;
>> > + switch (AK) {
>> > + case AK_GeneralPurpose:
>> > + Base = getShadowPtrForVAArgument(A, IRB, GpOffset);
>> > + GpOffset += 8;
>> > + break;
>> > + case AK_FloatingPoint:
>> > + Base = getShadowPtrForVAArgument(A, IRB, FpOffset);
>> > + FpOffset += 16;
>> > + break;
>> > + case AK_Memory:
>> > + uint64_t ArgSize = MS.TD->getTypeAllocSize(A->getType());
>> > + Base = getShadowPtrForVAArgument(A, IRB, OverflowOffset);
>> > + OverflowOffset += DataLayout::RoundUpAlignment(ArgSize, 8);
>> > + }
>> > + IRB.CreateStore(MSV.getShadow(A), Base);
>> > + }
>> > + Constant *OverflowSize =
>> > + ConstantInt::get(IRB.getInt64Ty(), OverflowOffset -
>> > AMD64FpEndOffset);
>> > + IRB.CreateStore(OverflowSize, MS.VAArgOverflowSizeTLS);
>> > + }
>> > +
>> > + /// \brief Compute the shadow address for a given va_arg.
>> > + Value *getShadowPtrForVAArgument(Value *A, IRBuilder<> &IRB,
>> > + int ArgOffset) {
>> > + Value *Base = IRB.CreatePointerCast(MS.VAArgTLS, MS.IntptrTy);
>> > + Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy,
>> > ArgOffset));
>> > + return IRB.CreateIntToPtr(Base,
>> > PointerType::get(MSV.getShadowTy(A), 0),
>> > + "_msarg");
>> > + }
>> > +
>> > + void visitVAStartInst(VAStartInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + VAStartInstrumentationList.push_back(&I);
>> > + Value *VAListTag = I.getArgOperand(0);
>> > + Value *ShadowPtr = MSV.getShadowPtr(VAListTag, IRB.getInt8Ty(),
>> > IRB);
>> > +
>> > + // Unpoison the whole __va_list_tag.
>> > + // FIXME: magic ABI constants.
>> > + IRB.CreateMemSet(ShadowPtr,
>> > Constant::getNullValue(IRB.getInt8Ty()),
>> > + /* size */24, /* alignment */16, false);
>> > + }
>> > +
>> > + void visitVACopyInst(VACopyInst &I) {
>> > + IRBuilder<> IRB(&I);
>> > + Value *VAListTag = I.getArgOperand(0);
>> > + Value *ShadowPtr = MSV.getShadowPtr(VAListTag, IRB.getInt8Ty(),
>> > IRB);
>> > +
>> > + // Unpoison the whole __va_list_tag.
>> > + // FIXME: magic ABI constants.
>> > + IRB.CreateMemSet(ShadowPtr,
>> > Constant::getNullValue(IRB.getInt8Ty()),
>> > + /* size */ 24, /* alignment */ 16, false);
>> > + }
>> > +
>> > + void finalizeInstrumentation() {
>> > + assert(!VAArgOverflowSize && !VAArgTLSCopy &&
>> > + "finalizeInstrumentation called twice");
>> > + if (!VAStartInstrumentationList.empty()) {
>> > + // If there is a va_start in this function, make a backup copy of
>> > + // va_arg_tls somewhere in the function entry block.
>> > + IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
>> > + VAArgOverflowSize = IRB.CreateLoad(MS.VAArgOverflowSizeTLS);
>> > + Value *CopySize =
>> > + IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, AMD64FpEndOffset),
>> > + VAArgOverflowSize);
>> > + VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C),
>> > CopySize);
>> > + IRB.CreateMemCpy(VAArgTLSCopy, MS.VAArgTLS, CopySize, 8);
>> > + }
>> > +
>> > + // Instrument va_start.
>> > + // Copy va_list shadow from the backup copy of the TLS contents.
>> > + for (size_t i = 0, n = VAStartInstrumentationList.size(); i < n;
>> > i++) {
>> > + CallInst *OrigInst = VAStartInstrumentationList[i];
>> > + IRBuilder<> IRB(OrigInst->getNextNode());
>> > + Value *VAListTag = OrigInst->getArgOperand(0);
>> > +
>> > + Value *RegSaveAreaPtrPtr =
>> > + IRB.CreateIntToPtr(
>> > + IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
>> > + ConstantInt::get(MS.IntptrTy, 16)),
>> > + Type::getInt64PtrTy(*MS.C));
>> > + Value *RegSaveAreaPtr = IRB.CreateLoad(RegSaveAreaPtrPtr);
>> > + Value *RegSaveAreaShadowPtr =
>> > + MSV.getShadowPtr(RegSaveAreaPtr, IRB.getInt8Ty(), IRB);
>> > + IRB.CreateMemCpy(RegSaveAreaShadowPtr, VAArgTLSCopy,
>> > + AMD64FpEndOffset, 16);
>> > +
>> > + Value *OverflowArgAreaPtrPtr =
>> > + IRB.CreateIntToPtr(
>> > + IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
>> > + ConstantInt::get(MS.IntptrTy, 8)),
>> > + Type::getInt64PtrTy(*MS.C));
>> > + Value *OverflowArgAreaPtr =
>> > IRB.CreateLoad(OverflowArgAreaPtrPtr);
>> > + Value *OverflowArgAreaShadowPtr =
>> > + MSV.getShadowPtr(OverflowArgAreaPtr, IRB.getInt8Ty(), IRB);
>> > + Value *SrcPtr =
>> > + getShadowPtrForVAArgument(VAArgTLSCopy, IRB, AMD64FpEndOffset);
>> > + IRB.CreateMemCpy(OverflowArgAreaShadowPtr, SrcPtr,
>> > VAArgOverflowSize, 16);
>> > + }
>> > + }
>> > +};
>> > +
>> > +VarArgHelper* CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
>> > + MemorySanitizerVisitor &Visitor) {
>> > + return new VarArgAMD64Helper(Func, Msan, Visitor);
>> > +}
>> > +
>> > +} // namespace
>> > +
>> > +bool MemorySanitizer::runOnFunction(Function &F) {
>> > + MemorySanitizerVisitor Visitor(F, *this);
>> > +
>> > + // Clear out readonly/readnone attributes.
>> > + AttrBuilder B;
>> > + B.addAttribute(Attributes::ReadOnly)
>> > + .addAttribute(Attributes::ReadNone);
>> > + F.removeAttribute(AttrListPtr::FunctionIndex,
>> > + Attributes::get(F.getContext(), B));
>> > +
>> > + return Visitor.runOnFunction();
>> > +}
>> >
>> > Propchange:
>> > llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
>> >
>> > ------------------------------------------------------------------------------
>> > svn:eol-style = LF
>> >
>> > Added: llvm/trunk/test/Instrumentation/MemorySanitizer/lit.local.cfg
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/MemorySanitizer/lit.local.cfg?rev=168866&view=auto
>> >
>> > ==============================================================================
>> > --- llvm/trunk/test/Instrumentation/MemorySanitizer/lit.local.cfg
>> > (added)
>> > +++ llvm/trunk/test/Instrumentation/MemorySanitizer/lit.local.cfg Thu
>> > Nov 29 03:57:20 2012
>> > @@ -0,0 +1 @@
>> > +config.suffixes = ['.ll', '.c', '.cpp']
>> >
>> > Added: llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll?rev=168866&view=auto
>> >
>> > ==============================================================================
>> > --- llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll
>> > (added)
>> > +++ llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll Thu
>> > Nov 29 03:57:20 2012
>> > @@ -0,0 +1,235 @@
>> > +; RUN: opt < %s -msan -S | FileCheck %s
>> > +target datalayout =
>> > "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
>> > +
>> > +; Check the presence of __msan_init
>> > +; CHECK: @llvm.global_ctors {{.*}} @__msan_init
>> > +
>> > +; load followed by cmp: check that we load the shadow and call
>> > __msan_warning.
>> > +define void @LoadAndCmp(i32* nocapture %a) nounwind uwtable {
>> > +entry:
>> > + %0 = load i32* %a, align 4
>> > + %tobool = icmp eq i32 %0, 0
>> > + br i1 %tobool, label %if.end, label %if.then
>> > +
>> > +if.then: ; preds = %entry
>> > + tail call void (...)* @foo() nounwind
>> > + br label %if.end
>> > +
>> > +if.end: ; preds = %entry,
>> > %if.then
>> > + ret void
>> > +}
>> > +
>> > +declare void @foo(...)
>> > +
>> > +; CHECK: define void @LoadAndCmp
>> > +; CHECK: = load
>> > +; CHECK: = load
>> > +; CHECK: call void @__msan_warning_noreturn()
>> > +; CHECK: }
>> > +
>> > +; Check that we store the shadow for the retval.
>> > +define i32 @ReturnInt() nounwind uwtable readnone {
>> > +entry:
>> > + ret i32 123
>> > +}
>> > +
>> > +; CHECK: define i32 @ReturnInt()
>> > +; CHECK: store i32 0,{{.*}}__msan_retval_tls
>> > +; CHECK: }
>> > +
>> > +; Check that we get the shadow for the retval.
>> > +define void @CopyRetVal(i32* nocapture %a) nounwind uwtable {
>> > +entry:
>> > + %call = tail call i32 @ReturnInt() nounwind
>> > + store i32 %call, i32* %a, align 4
>> > + ret void
>> > +}
>> > +
>> > +; CHECK: define void @CopyRetVal
>> > +; CHECK: load{{.*}}__msan_retval_tls
>> > +; CHECK: store
>> > +; CHECK: store
>> > +; CHECK: }
>> > +
>> > +
>> > +; Check that we generate PHIs for shadow.
>> > +define void @FuncWithPhi(i32* nocapture %a, i32* %b, i32* nocapture %c)
>> > nounwind uwtable {
>> > +entry:
>> > + %tobool = icmp eq i32* %b, null
>> > + br i1 %tobool, label %if.else, label %if.then
>> > +
>> > + if.then: ; preds = %entry
>> > + %0 = load i32* %b, align 4
>> > + br label %if.end
>> > +
>> > + if.else: ; preds = %entry
>> > + %1 = load i32* %c, align 4
>> > + br label %if.end
>> > +
>> > + if.end: ; preds = %if.else,
>> > %if.then
>> > + %t.0 = phi i32 [ %0, %if.then ], [ %1, %if.else ]
>> > + store i32 %t.0, i32* %a, align 4
>> > + ret void
>> > +}
>> > +
>> > +; CHECK: define void @FuncWithPhi
>> > +; CHECK: = phi
>> > +; CHECK-NEXT: = phi
>> > +; CHECK: store
>> > +; CHECK: store
>> > +; CHECK: }
>> > +
>> > +; Compute shadow for "x << 10"
>> > +define void @ShlConst(i32* nocapture %x) nounwind uwtable {
>> > +entry:
>> > + %0 = load i32* %x, align 4
>> > + %1 = shl i32 %0, 10
>> > + store i32 %1, i32* %x, align 4
>> > + ret void
>> > +}
>> > +
>> > +; CHECK: define void @ShlConst
>> > +; CHECK: = load
>> > +; CHECK: = load
>> > +; CHECK: shl
>> > +; CHECK: shl
>> > +; CHECK: store
>> > +; CHECK: store
>> > +; CHECK: }
>> > +
>> > +; Compute shadow for "10 << x": it should have 'sext i1'.
>> > +define void @ShlNonConst(i32* nocapture %x) nounwind uwtable {
>> > +entry:
>> > + %0 = load i32* %x, align 4
>> > + %1 = shl i32 10, %0
>> > + store i32 %1, i32* %x, align 4
>> > + ret void
>> > +}
>> > +
>> > +; CHECK: define void @ShlNonConst
>> > +; CHECK: = load
>> > +; CHECK: = load
>> > +; CHECK: = sext i1
>> > +; CHECK: store
>> > +; CHECK: store
>> > +; CHECK: }
>> > +
>> > +; SExt
>> > +define void @SExt(i32* nocapture %a, i16* nocapture %b) nounwind
>> > uwtable {
>> > +entry:
>> > + %0 = load i16* %b, align 2
>> > + %1 = sext i16 %0 to i32
>> > + store i32 %1, i32* %a, align 4
>> > + ret void
>> > +}
>> > +
>> > +; CHECK: define void @SExt
>> > +; CHECK: = load
>> > +; CHECK: = load
>> > +; CHECK: = sext
>> > +; CHECK: = sext
>> > +; CHECK: store
>> > +; CHECK: store
>> > +; CHECK: }
>> > +
>> > +
>> > +; memset
>> > +define void @MemSet(i8* nocapture %x) nounwind uwtable {
>> > +entry:
>> > + call void @llvm.memset.p0i8.i64(i8* %x, i8 42, i64 10, i32 1, i1
>> > false)
>> > + ret void
>> > +}
>> > +
>> > +declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1)
>> > nounwind
>> > +
>> > +; CHECK: define void @MemSet
>> > +; CHECK: call void @llvm.memset.p0i8.i64
>> > +; CHECK: call void @llvm.memset.p0i8.i64
>> > +; CHECK: }
>> > +
>> > +
>> > +; memcpy
>> > +define void @MemCpy(i8* nocapture %x, i8* nocapture %y) nounwind
>> > uwtable {
>> > +entry:
>> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %x, i8* %y, i64 10, i32 1,
>> > i1 false)
>> > + ret void
>> > +}
>> > +
>> > +declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture,
>> > i64, i32, i1) nounwind
>> > +
>> > +; CHECK: define void @MemCpy
>> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64
>> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64
>> > +; CHECK: }
>> > +
>> > +
>> > +; memmove is lowered to a call
>> > +define void @MemMove(i8* nocapture %x, i8* nocapture %y) nounwind
>> > uwtable {
>> > +entry:
>> > + call void @llvm.memmove.p0i8.p0i8.i64(i8* %x, i8* %y, i64 10, i32 1,
>> > i1 false)
>> > + ret void
>> > +}
>> > +
>> > +declare void @llvm.memmove.p0i8.p0i8.i64(i8* nocapture, i8* nocapture,
>> > i64, i32, i1) nounwind
>> > +
>> > +; CHECK: define void @MemMove
>> > +; CHECK: call i8* @memmove
>> > +; CHECK: }
>> > +
>> > +
>> > +; Check that we propagate shadow for "select"
>> > +
>> > +define i32 @Select(i32 %a, i32 %b, i32 %c) nounwind uwtable readnone {
>> > +entry:
>> > + %tobool = icmp ne i32 %c, 0
>> > + %cond = select i1 %tobool, i32 %a, i32 %b
>> > + ret i32 %cond
>> > +}
>> > +
>> > +; CHECK: define i32 @Select
>> > +; CHECK: select
>> > +; CHECK-NEXT: select
>> > +; CHECK: }
>> > +
>> > +
>> > +define i8* @IntToPtr(i64 %x) nounwind uwtable readnone {
>> > +entry:
>> > + %0 = inttoptr i64 %x to i8*
>> > + ret i8* %0
>> > +}
>> > +
>> > +; CHECK: define i8* @IntToPtr
>> > +; CHECK: load i64*{{.*}}__msan_param_tls
>> > +; CHECK-NEXT: inttoptr
>> > +; CHECK-NEXT: store i64{{.*}}__msan_retval_tls
>> > +; CHECK: }
>> > +
>> > +
>> > +define i8* @IntToPtr_ZExt(i16 %x) nounwind uwtable readnone {
>> > +entry:
>> > + %0 = inttoptr i16 %x to i8*
>> > + ret i8* %0
>> > +}
>> > +
>> > +; CHECK: define i8* @IntToPtr_ZExt
>> > +; CHECK: zext
>> > +; CHECK-NEXT: inttoptr
>> > +; CHECK: }
>> > +
>> > +
>> > +; Check that we insert exactly one check on udiv
>> > +; (2nd arg shadow is checked, 1st arg shadow is propagated)
>> > +
>> > +define i32 @Div(i32 %a, i32 %b) nounwind uwtable readnone {
>> > +entry:
>> > + %div = udiv i32 %a, %b
>> > + ret i32 %div
>> > +}
>> > +
>> > +; CHECK: define i32 @Div
>> > +; CHECK: icmp
>> > +; CHECK: br
>> > +; CHECK-NOT: icmp
>> > +; CHECK: udiv
>> > +; CHECK-NOT: icmp
>> > +; CHECK: }
>> >
>> >
>> > _______________________________________________
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