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llvm-project/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp

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//===- MemorySanitizer.cpp - detector of uninitialized reads --------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
/// \file
/// This file is a part of MemorySanitizer, a detector of uninitialized
/// reads.
///
/// 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).
///
/// Origin tracking.
///
/// MemorySanitizer can track origins (allocation points) of all uninitialized
/// values. This behavior is controlled with a flag (msan-track-origins) and is
/// disabled by default.
///
/// Origins are 4-byte values created and interpreted by the runtime library.
/// They are stored in a second shadow mapping, one 4-byte value for 4 bytes
/// of application memory. Propagation of origins is basically a bunch of
/// "select" instructions that pick the origin of a dirty argument, if an
/// instruction has one.
///
/// Every 4 aligned, consecutive bytes of application memory have one origin
/// value associated with them. If these bytes contain uninitialized data
/// coming from 2 different allocations, the last store wins. Because of this,
/// MemorySanitizer reports can show unrelated origins, but this is unlikely in
/// practice.
///
/// Origins are meaningless for fully initialized values, so MemorySanitizer
/// avoids storing origin to memory when a fully initialized value is stored.
/// This way it avoids needless overwriting origin of the 4-byte region on
/// a short (i.e. 1 byte) clean store, and it is also good for performance.
///
/// Atomic handling.
///
/// Ideally, every atomic store of application value should update the
/// corresponding shadow location in an atomic way. Unfortunately, atomic store
/// of two disjoint locations can not be done without severe slowdown.
///
/// Therefore, we implement an approximation that may err on the safe side.
/// In this implementation, every atomically accessed location in the program
/// may only change from (partially) uninitialized to fully initialized, but
/// not the other way around. We load the shadow _after_ the application load,
/// and we store the shadow _before_ the app store. Also, we always store clean
/// shadow (if the application store is atomic). This way, if the store-load
/// pair constitutes a happens-before arc, shadow store and load are correctly
/// ordered such that the load will get either the value that was stored, or
/// some later value (which is always clean).
///
/// This does not work very well with Compare-And-Swap (CAS) and
/// Read-Modify-Write (RMW) operations. To follow the above logic, CAS and RMW
/// must store the new shadow before the app operation, and load the shadow
/// after the app operation. Computers don't work this way. Current
/// implementation ignores the load aspect of CAS/RMW, always returning a clean
/// value. It implements the store part as a simple atomic store by storing a
/// clean shadow.
///
/// Instrumenting inline assembly.
///
/// For inline assembly code LLVM has little idea about which memory locations
/// become initialized depending on the arguments. It can be possible to figure
/// out which arguments are meant to point to inputs and outputs, but the
/// actual semantics can be only visible at runtime. In the Linux kernel it's
/// also possible that the arguments only indicate the offset for a base taken
/// from a segment register, so it's dangerous to treat any asm() arguments as
/// pointers. We take a conservative approach generating calls to
/// __msan_instrument_asm_store(ptr, size)
/// , which defer the memory unpoisoning to the runtime library.
/// The latter can perform more complex address checks to figure out whether
/// it's safe to touch the shadow memory.
/// Like with atomic operations, we call __msan_instrument_asm_store() before
/// the assembly call, so that changes to the shadow memory will be seen by
/// other threads together with main memory initialization.
///
/// KernelMemorySanitizer (KMSAN) implementation.
///
/// The major differences between KMSAN and MSan instrumentation are:
/// - KMSAN always tracks the origins and implies msan-keep-going=true;
/// - KMSAN allocates shadow and origin memory for each page separately, so
/// there are no explicit accesses to shadow and origin in the
/// instrumentation.
/// Shadow and origin values for a particular X-byte memory location
/// (X=1,2,4,8) are accessed through pointers obtained via the
/// __msan_metadata_ptr_for_load_X(ptr)
/// __msan_metadata_ptr_for_store_X(ptr)
/// functions. The corresponding functions check that the X-byte accesses
/// are possible and returns the pointers to shadow and origin memory.
/// Arbitrary sized accesses are handled with:
/// __msan_metadata_ptr_for_load_n(ptr, size)
/// __msan_metadata_ptr_for_store_n(ptr, size);
/// - TLS variables are stored in a single per-task struct. A call to a
/// function __msan_get_context_state() returning a pointer to that struct
/// is inserted into every instrumented function before the entry block;
/// - __msan_warning() takes a 32-bit origin parameter;
/// - local variables are poisoned with __msan_poison_alloca() upon function
/// entry and unpoisoned with __msan_unpoison_alloca() before leaving the
/// function;
/// - the pass doesn't declare any global variables or add global constructors
/// to the translation unit.
///
/// Also, KMSAN currently ignores uninitialized memory passed into inline asm
/// calls, making sure we're on the safe side wrt. possible false positives.
///
/// KernelMemorySanitizer only supports X86_64 at the moment.
///
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Instrumentation/MemorySanitizer.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/InstVisitor.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/IntrinsicsX86.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/ValueMap.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/AtomicOrdering.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <memory>
#include <string>
#include <tuple>
using namespace llvm;
#define DEBUG_TYPE "msan"
static const unsigned kOriginSize = 4;
static const Align kMinOriginAlignment = Align(4);
static const Align kShadowTLSAlignment = Align(8);
// These constants must be kept in sync with the ones in msan.h.
static const unsigned kParamTLSSize = 800;
static const unsigned kRetvalTLSSize = 800;
// Accesses sizes are powers of two: 1, 2, 4, 8.
static const size_t kNumberOfAccessSizes = 4;
/// Track origins of uninitialized values.
///
/// Adds a section to MemorySanitizer report that points to the allocation
/// (stack or heap) the uninitialized bits came from originally.
static cl::opt<int> ClTrackOrigins("msan-track-origins",
cl::desc("Track origins (allocation sites) of poisoned memory"),
cl::Hidden, cl::init(0));
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 pattern"),
cl::Hidden, cl::init(0xff));
static cl::opt<bool> ClPoisonUndef("msan-poison-undef",
cl::desc("poison undef temps"),
cl::Hidden, cl::init(true));
static cl::opt<bool> ClHandleICmp("msan-handle-icmp",
cl::desc("propagate shadow through ICmpEQ and ICmpNE"),
cl::Hidden, cl::init(true));
static cl::opt<bool> ClHandleICmpExact("msan-handle-icmp-exact",
cl::desc("exact handling of relational integer ICmp"),
cl::Hidden, cl::init(false));
static cl::opt<bool> ClHandleLifetimeIntrinsics(
"msan-handle-lifetime-intrinsics",
cl::desc(
"when possible, poison scoped variables at the beginning of the scope "
"(slower, but more precise)"),
cl::Hidden, cl::init(true));
// When compiling the Linux kernel, we sometimes see false positives related to
// MSan being unable to understand that inline assembly calls may initialize
// local variables.
// This flag makes the compiler conservatively unpoison every memory location
// passed into an assembly call. Note that this may cause false positives.
// Because it's impossible to figure out the array sizes, we can only unpoison
// the first sizeof(type) bytes for each type* pointer.
// The instrumentation is only enabled in KMSAN builds, and only if
// -msan-handle-asm-conservative is on. This is done because we may want to
// quickly disable assembly instrumentation when it breaks.
static cl::opt<bool> ClHandleAsmConservative(
"msan-handle-asm-conservative",
cl::desc("conservative handling of inline assembly"), 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<int> ClInstrumentationWithCallThreshold(
"msan-instrumentation-with-call-threshold",
cl::desc(
"If the function being instrumented requires more than "
"this number of checks and origin stores, use callbacks instead of "
"inline checks (-1 means never use callbacks)."),
cl::Hidden, cl::init(3500));
static cl::opt<bool>
ClEnableKmsan("msan-kernel",
cl::desc("Enable KernelMemorySanitizer instrumentation"),
cl::Hidden, cl::init(false));
// This is an experiment to enable handling of cases where shadow is a non-zero
// compile-time constant. For some unexplainable reason they were silently
// ignored in the instrumentation.
static cl::opt<bool> ClCheckConstantShadow("msan-check-constant-shadow",
cl::desc("Insert checks for constant shadow values"),
cl::Hidden, cl::init(false));
// This is off by default because of a bug in gold:
// https://sourceware.org/bugzilla/show_bug.cgi?id=19002
static cl::opt<bool> ClWithComdat("msan-with-comdat",
cl::desc("Place MSan constructors in comdat sections"),
cl::Hidden, cl::init(false));
// These options allow to specify custom memory map parameters
// See MemoryMapParams for details.
static cl::opt<uint64_t> ClAndMask("msan-and-mask",
cl::desc("Define custom MSan AndMask"),
cl::Hidden, cl::init(0));
static cl::opt<uint64_t> ClXorMask("msan-xor-mask",
cl::desc("Define custom MSan XorMask"),
cl::Hidden, cl::init(0));
static cl::opt<uint64_t> ClShadowBase("msan-shadow-base",
cl::desc("Define custom MSan ShadowBase"),
cl::Hidden, cl::init(0));
static cl::opt<uint64_t> ClOriginBase("msan-origin-base",
cl::desc("Define custom MSan OriginBase"),
cl::Hidden, cl::init(0));
static const char *const kMsanModuleCtorName = "msan.module_ctor";
static const char *const kMsanInitName = "__msan_init";
namespace {
// Memory map parameters used in application-to-shadow address calculation.
// Offset = (Addr & ~AndMask) ^ XorMask
// Shadow = ShadowBase + Offset
// Origin = OriginBase + Offset
struct MemoryMapParams {
uint64_t AndMask;
uint64_t XorMask;
uint64_t ShadowBase;
uint64_t OriginBase;
};
struct PlatformMemoryMapParams {
const MemoryMapParams *bits32;
const MemoryMapParams *bits64;
};
} // end anonymous namespace
// i386 Linux
static const MemoryMapParams Linux_I386_MemoryMapParams = {
0x000080000000, // AndMask
0, // XorMask (not used)
0, // ShadowBase (not used)
0x000040000000, // OriginBase
};
// x86_64 Linux
static const MemoryMapParams Linux_X86_64_MemoryMapParams = {
#ifdef MSAN_LINUX_X86_64_OLD_MAPPING
0x400000000000, // AndMask
0, // XorMask (not used)
0, // ShadowBase (not used)
0x200000000000, // OriginBase
#else
0, // AndMask (not used)
0x500000000000, // XorMask
0, // ShadowBase (not used)
0x100000000000, // OriginBase
#endif
};
// mips64 Linux
static const MemoryMapParams Linux_MIPS64_MemoryMapParams = {
0, // AndMask (not used)
0x008000000000, // XorMask
0, // ShadowBase (not used)
0x002000000000, // OriginBase
};
// ppc64 Linux
static const MemoryMapParams Linux_PowerPC64_MemoryMapParams = {
0xE00000000000, // AndMask
0x100000000000, // XorMask
0x080000000000, // ShadowBase
0x1C0000000000, // OriginBase
};
// s390x Linux
static const MemoryMapParams Linux_S390X_MemoryMapParams = {
0xC00000000000, // AndMask
0, // XorMask (not used)
0x080000000000, // ShadowBase
0x1C0000000000, // OriginBase
};
// aarch64 Linux
static const MemoryMapParams Linux_AArch64_MemoryMapParams = {
0, // AndMask (not used)
0x06000000000, // XorMask
0, // ShadowBase (not used)
0x01000000000, // OriginBase
};
// i386 FreeBSD
static const MemoryMapParams FreeBSD_I386_MemoryMapParams = {
0x000180000000, // AndMask
0x000040000000, // XorMask
0x000020000000, // ShadowBase
0x000700000000, // OriginBase
};
// x86_64 FreeBSD
static const MemoryMapParams FreeBSD_X86_64_MemoryMapParams = {
0xc00000000000, // AndMask
0x200000000000, // XorMask
0x100000000000, // ShadowBase
0x380000000000, // OriginBase
};
// x86_64 NetBSD
static const MemoryMapParams NetBSD_X86_64_MemoryMapParams = {
0, // AndMask
0x500000000000, // XorMask
0, // ShadowBase
0x100000000000, // OriginBase
};
static const PlatformMemoryMapParams Linux_X86_MemoryMapParams = {
&Linux_I386_MemoryMapParams,
&Linux_X86_64_MemoryMapParams,
};
static const PlatformMemoryMapParams Linux_MIPS_MemoryMapParams = {
nullptr,
&Linux_MIPS64_MemoryMapParams,
};
static const PlatformMemoryMapParams Linux_PowerPC_MemoryMapParams = {
nullptr,
&Linux_PowerPC64_MemoryMapParams,
};
static const PlatformMemoryMapParams Linux_S390_MemoryMapParams = {
nullptr,
&Linux_S390X_MemoryMapParams,
};
static const PlatformMemoryMapParams Linux_ARM_MemoryMapParams = {
nullptr,
&Linux_AArch64_MemoryMapParams,
};
static const PlatformMemoryMapParams FreeBSD_X86_MemoryMapParams = {
&FreeBSD_I386_MemoryMapParams,
&FreeBSD_X86_64_MemoryMapParams,
};
static const PlatformMemoryMapParams NetBSD_X86_MemoryMapParams = {
nullptr,
&NetBSD_X86_64_MemoryMapParams,
};
namespace {
/// Instrument functions of a module to detect uninitialized reads.
///
/// Instantiating MemorySanitizer inserts the msan runtime library API function
/// declarations into the module if they don't exist already. Instantiating
/// ensures the __msan_init function is in the list of global constructors for
/// the module.
class MemorySanitizer {
public:
MemorySanitizer(Module &M, MemorySanitizerOptions Options)
: CompileKernel(Options.Kernel), TrackOrigins(Options.TrackOrigins),
Recover(Options.Recover) {
initializeModule(M);
}
// MSan cannot be moved or copied because of MapParams.
MemorySanitizer(MemorySanitizer &&) = delete;
MemorySanitizer &operator=(MemorySanitizer &&) = delete;
MemorySanitizer(const MemorySanitizer &) = delete;
MemorySanitizer &operator=(const MemorySanitizer &) = delete;
bool sanitizeFunction(Function &F, TargetLibraryInfo &TLI);
private:
friend struct MemorySanitizerVisitor;
friend struct VarArgAMD64Helper;
friend struct VarArgMIPS64Helper;
friend struct VarArgAArch64Helper;
friend struct VarArgPowerPC64Helper;
friend struct VarArgSystemZHelper;
void initializeModule(Module &M);
void initializeCallbacks(Module &M);
void createKernelApi(Module &M);
void createUserspaceApi(Module &M);
/// True if we're compiling the Linux kernel.
bool CompileKernel;
/// Track origins (allocation points) of uninitialized values.
int TrackOrigins;
bool Recover;
LLVMContext *C;
Type *IntptrTy;
Type *OriginTy;
// XxxTLS variables represent the per-thread state in MSan and per-task state
// in KMSAN.
// For the userspace these point to thread-local globals. In the kernel land
// they point to the members of a per-task struct obtained via a call to
// __msan_get_context_state().
/// Thread-local shadow storage for function parameters.
Value *ParamTLS;
/// Thread-local origin storage for function parameters.
Value *ParamOriginTLS;
/// Thread-local shadow storage for function return value.
Value *RetvalTLS;
/// Thread-local origin storage for function return value.
Value *RetvalOriginTLS;
/// Thread-local shadow storage for in-register va_arg function
/// parameters (x86_64-specific).
Value *VAArgTLS;
/// Thread-local shadow storage for in-register va_arg function
/// parameters (x86_64-specific).
Value *VAArgOriginTLS;
/// Thread-local shadow storage for va_arg overflow area
/// (x86_64-specific).
Value *VAArgOverflowSizeTLS;
/// Thread-local space used to pass origin value to the UMR reporting
/// function.
Value *OriginTLS;
/// Are the instrumentation callbacks set up?
bool CallbacksInitialized = false;
/// The run-time callback to print a warning.
FunctionCallee WarningFn;
// These arrays are indexed by log2(AccessSize).
FunctionCallee MaybeWarningFn[kNumberOfAccessSizes];
FunctionCallee MaybeStoreOriginFn[kNumberOfAccessSizes];
/// Run-time helper that generates a new origin value for a stack
/// allocation.
FunctionCallee MsanSetAllocaOrigin4Fn;
/// Run-time helper that poisons stack on function entry.
FunctionCallee MsanPoisonStackFn;
/// Run-time helper that records a store (or any event) of an
/// uninitialized value and returns an updated origin id encoding this info.
FunctionCallee MsanChainOriginFn;
/// MSan runtime replacements for memmove, memcpy and memset.
FunctionCallee MemmoveFn, MemcpyFn, MemsetFn;
/// KMSAN callback for task-local function argument shadow.
StructType *MsanContextStateTy;
FunctionCallee MsanGetContextStateFn;
/// Functions for poisoning/unpoisoning local variables
FunctionCallee MsanPoisonAllocaFn, MsanUnpoisonAllocaFn;
/// Each of the MsanMetadataPtrXxx functions returns a pair of shadow/origin
/// pointers.
FunctionCallee MsanMetadataPtrForLoadN, MsanMetadataPtrForStoreN;
FunctionCallee MsanMetadataPtrForLoad_1_8[4];
FunctionCallee MsanMetadataPtrForStore_1_8[4];
FunctionCallee MsanInstrumentAsmStoreFn;
/// Helper to choose between different MsanMetadataPtrXxx().
FunctionCallee getKmsanShadowOriginAccessFn(bool isStore, int size);
/// Memory map parameters used in application-to-shadow calculation.
const MemoryMapParams *MapParams;
/// Custom memory map parameters used when -msan-shadow-base or
// -msan-origin-base is provided.
MemoryMapParams CustomMapParams;
MDNode *ColdCallWeights;
/// Branch weights for origin store.
MDNode *OriginStoreWeights;
/// An empty volatile inline asm that prevents callback merge.
InlineAsm *EmptyAsm;
};
void insertModuleCtor(Module &M) {
getOrCreateSanitizerCtorAndInitFunctions(
M, kMsanModuleCtorName, kMsanInitName,
/*InitArgTypes=*/{},
/*InitArgs=*/{},
// This callback is invoked when the functions are created the first
// time. Hook them into the global ctors list in that case:
[&](Function *Ctor, FunctionCallee) {
if (!ClWithComdat) {
appendToGlobalCtors(M, Ctor, 0);
return;
}
Comdat *MsanCtorComdat = M.getOrInsertComdat(kMsanModuleCtorName);
Ctor->setComdat(MsanCtorComdat);
appendToGlobalCtors(M, Ctor, 0, Ctor);
});
}
/// A legacy function pass for msan instrumentation.
///
/// Instruments functions to detect uninitialized reads.
struct MemorySanitizerLegacyPass : public FunctionPass {
// Pass identification, replacement for typeid.
static char ID;
MemorySanitizerLegacyPass(MemorySanitizerOptions Options = {})
: FunctionPass(ID), Options(Options) {}
StringRef getPassName() const override { return "MemorySanitizerLegacyPass"; }
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<TargetLibraryInfoWrapperPass>();
}
bool runOnFunction(Function &F) override {
return MSan->sanitizeFunction(
F, getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F));
}
bool doInitialization(Module &M) override;
Optional<MemorySanitizer> MSan;
MemorySanitizerOptions Options;
};
template <class T> T getOptOrDefault(const cl::opt<T> &Opt, T Default) {
return (Opt.getNumOccurrences() > 0) ? Opt : Default;
}
} // end anonymous namespace
MemorySanitizerOptions::MemorySanitizerOptions(int TO, bool R, bool K)
: Kernel(getOptOrDefault(ClEnableKmsan, K)),
TrackOrigins(getOptOrDefault(ClTrackOrigins, Kernel ? 2 : TO)),
Recover(getOptOrDefault(ClKeepGoing, Kernel || R)) {}
PreservedAnalyses MemorySanitizerPass::run(Function &F,
FunctionAnalysisManager &FAM) {
MemorySanitizer Msan(*F.getParent(), Options);
if (Msan.sanitizeFunction(F, FAM.getResult<TargetLibraryAnalysis>(F)))
return PreservedAnalyses::none();
return PreservedAnalyses::all();
}
PreservedAnalyses MemorySanitizerPass::run(Module &M,
ModuleAnalysisManager &AM) {
if (Options.Kernel)
return PreservedAnalyses::all();
insertModuleCtor(M);
return PreservedAnalyses::none();
}
char MemorySanitizerLegacyPass::ID = 0;
INITIALIZE_PASS_BEGIN(MemorySanitizerLegacyPass, "msan",
"MemorySanitizer: detects uninitialized reads.", false,
false)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_END(MemorySanitizerLegacyPass, "msan",
"MemorySanitizer: detects uninitialized reads.", false,
false)
FunctionPass *
llvm::createMemorySanitizerLegacyPassPass(MemorySanitizerOptions Options) {
return new MemorySanitizerLegacyPass(Options);
}
/// 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, "");
}
/// Create KMSAN API callbacks.
void MemorySanitizer::createKernelApi(Module &M) {
IRBuilder<> IRB(*C);
// These will be initialized in insertKmsanPrologue().
RetvalTLS = nullptr;
RetvalOriginTLS = nullptr;
ParamTLS = nullptr;
ParamOriginTLS = nullptr;
VAArgTLS = nullptr;
VAArgOriginTLS = nullptr;
VAArgOverflowSizeTLS = nullptr;
// OriginTLS is unused in the kernel.
OriginTLS = nullptr;
// __msan_warning() in the kernel takes an origin.
WarningFn = M.getOrInsertFunction("__msan_warning", IRB.getVoidTy(),
IRB.getInt32Ty());
// Requests the per-task context state (kmsan_context_state*) from the
// runtime library.
MsanContextStateTy = StructType::get(
ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8),
ArrayType::get(IRB.getInt64Ty(), kRetvalTLSSize / 8),
ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8),
ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8), /* va_arg_origin */
IRB.getInt64Ty(), ArrayType::get(OriginTy, kParamTLSSize / 4), OriginTy,
OriginTy);
MsanGetContextStateFn = M.getOrInsertFunction(
"__msan_get_context_state", PointerType::get(MsanContextStateTy, 0));
Type *RetTy = StructType::get(PointerType::get(IRB.getInt8Ty(), 0),
PointerType::get(IRB.getInt32Ty(), 0));
for (int ind = 0, size = 1; ind < 4; ind++, size <<= 1) {
std::string name_load =
"__msan_metadata_ptr_for_load_" + std::to_string(size);
std::string name_store =
"__msan_metadata_ptr_for_store_" + std::to_string(size);
MsanMetadataPtrForLoad_1_8[ind] = M.getOrInsertFunction(
name_load, RetTy, PointerType::get(IRB.getInt8Ty(), 0));
MsanMetadataPtrForStore_1_8[ind] = M.getOrInsertFunction(
name_store, RetTy, PointerType::get(IRB.getInt8Ty(), 0));
}
MsanMetadataPtrForLoadN = M.getOrInsertFunction(
"__msan_metadata_ptr_for_load_n", RetTy,
PointerType::get(IRB.getInt8Ty(), 0), IRB.getInt64Ty());
MsanMetadataPtrForStoreN = M.getOrInsertFunction(
"__msan_metadata_ptr_for_store_n", RetTy,
PointerType::get(IRB.getInt8Ty(), 0), IRB.getInt64Ty());
// Functions for poisoning and unpoisoning memory.
MsanPoisonAllocaFn =
M.getOrInsertFunction("__msan_poison_alloca", IRB.getVoidTy(),
IRB.getInt8PtrTy(), IntptrTy, IRB.getInt8PtrTy());
MsanUnpoisonAllocaFn = M.getOrInsertFunction(
"__msan_unpoison_alloca", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy);
}
static Constant *getOrInsertGlobal(Module &M, StringRef Name, Type *Ty) {
return M.getOrInsertGlobal(Name, Ty, [&] {
return new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage,
nullptr, Name, nullptr,
GlobalVariable::InitialExecTLSModel);
});
}
/// Insert declarations for userspace-specific functions and globals.
void MemorySanitizer::createUserspaceApi(Module &M) {
IRBuilder<> IRB(*C);
// Create the callback.
// FIXME: this function should have "Cold" calling conv,
// which is not yet implemented.
StringRef WarningFnName = Recover ? "__msan_warning"
: "__msan_warning_noreturn";
WarningFn = M.getOrInsertFunction(WarningFnName, IRB.getVoidTy());
// Create the global TLS variables.
RetvalTLS =
getOrInsertGlobal(M, "__msan_retval_tls",
ArrayType::get(IRB.getInt64Ty(), kRetvalTLSSize / 8));
RetvalOriginTLS = getOrInsertGlobal(M, "__msan_retval_origin_tls", OriginTy);
ParamTLS =
getOrInsertGlobal(M, "__msan_param_tls",
ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8));
ParamOriginTLS =
getOrInsertGlobal(M, "__msan_param_origin_tls",
ArrayType::get(OriginTy, kParamTLSSize / 4));
VAArgTLS =
getOrInsertGlobal(M, "__msan_va_arg_tls",
ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8));
VAArgOriginTLS =
getOrInsertGlobal(M, "__msan_va_arg_origin_tls",
ArrayType::get(OriginTy, kParamTLSSize / 4));
VAArgOverflowSizeTLS =
getOrInsertGlobal(M, "__msan_va_arg_overflow_size_tls", IRB.getInt64Ty());
OriginTLS = getOrInsertGlobal(M, "__msan_origin_tls", IRB.getInt32Ty());
for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
AccessSizeIndex++) {
unsigned AccessSize = 1 << AccessSizeIndex;
std::string FunctionName = "__msan_maybe_warning_" + itostr(AccessSize);
SmallVector<std::pair<unsigned, Attribute>, 2> MaybeWarningFnAttrs;
MaybeWarningFnAttrs.push_back(std::make_pair(
AttributeList::FirstArgIndex, Attribute::get(*C, Attribute::ZExt)));
MaybeWarningFnAttrs.push_back(std::make_pair(
AttributeList::FirstArgIndex + 1, Attribute::get(*C, Attribute::ZExt)));
MaybeWarningFn[AccessSizeIndex] = M.getOrInsertFunction(
FunctionName, AttributeList::get(*C, MaybeWarningFnAttrs),
IRB.getVoidTy(), IRB.getIntNTy(AccessSize * 8), IRB.getInt32Ty());
FunctionName = "__msan_maybe_store_origin_" + itostr(AccessSize);
SmallVector<std::pair<unsigned, Attribute>, 2> MaybeStoreOriginFnAttrs;
MaybeStoreOriginFnAttrs.push_back(std::make_pair(
AttributeList::FirstArgIndex, Attribute::get(*C, Attribute::ZExt)));
MaybeStoreOriginFnAttrs.push_back(std::make_pair(
AttributeList::FirstArgIndex + 2, Attribute::get(*C, Attribute::ZExt)));
MaybeStoreOriginFn[AccessSizeIndex] = M.getOrInsertFunction(
FunctionName, AttributeList::get(*C, MaybeStoreOriginFnAttrs),
IRB.getVoidTy(), IRB.getIntNTy(AccessSize * 8), IRB.getInt8PtrTy(),
IRB.getInt32Ty());
}
MsanSetAllocaOrigin4Fn = M.getOrInsertFunction(
"__msan_set_alloca_origin4", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy,
IRB.getInt8PtrTy(), IntptrTy);
MsanPoisonStackFn =
M.getOrInsertFunction("__msan_poison_stack", IRB.getVoidTy(),
IRB.getInt8PtrTy(), IntptrTy);
}
/// Insert extern declaration of runtime-provided functions and globals.
void MemorySanitizer::initializeCallbacks(Module &M) {
// Only do this once.
if (CallbacksInitialized)
return;
IRBuilder<> IRB(*C);
// Initialize callbacks that are common for kernel and userspace
// instrumentation.
MsanChainOriginFn = M.getOrInsertFunction(
"__msan_chain_origin", IRB.getInt32Ty(), IRB.getInt32Ty());
MemmoveFn = M.getOrInsertFunction(
"__msan_memmove", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
IRB.getInt8PtrTy(), IntptrTy);
MemcpyFn = M.getOrInsertFunction(
"__msan_memcpy", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
IntptrTy);
MemsetFn = M.getOrInsertFunction(
"__msan_memset", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt32Ty(),
IntptrTy);
// We insert an empty inline asm after __msan_report* to avoid callback merge.
EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
StringRef(""), StringRef(""),
/*hasSideEffects=*/true);
MsanInstrumentAsmStoreFn =
M.getOrInsertFunction("__msan_instrument_asm_store", IRB.getVoidTy(),
PointerType::get(IRB.getInt8Ty(), 0), IntptrTy);
if (CompileKernel) {
createKernelApi(M);
} else {
createUserspaceApi(M);
}
CallbacksInitialized = true;
}
FunctionCallee MemorySanitizer::getKmsanShadowOriginAccessFn(bool isStore,
int size) {
FunctionCallee *Fns =
isStore ? MsanMetadataPtrForStore_1_8 : MsanMetadataPtrForLoad_1_8;
switch (size) {
case 1:
return Fns[0];
case 2:
return Fns[1];
case 4:
return Fns[2];
case 8:
return Fns[3];
default:
return nullptr;
}
}
/// Module-level initialization.
///
/// inserts a call to __msan_init to the module's constructor list.
void MemorySanitizer::initializeModule(Module &M) {
auto &DL = M.getDataLayout();
bool ShadowPassed = ClShadowBase.getNumOccurrences() > 0;
bool OriginPassed = ClOriginBase.getNumOccurrences() > 0;
// Check the overrides first
if (ShadowPassed || OriginPassed) {
CustomMapParams.AndMask = ClAndMask;
CustomMapParams.XorMask = ClXorMask;
CustomMapParams.ShadowBase = ClShadowBase;
CustomMapParams.OriginBase = ClOriginBase;
MapParams = &CustomMapParams;
} else {
Triple TargetTriple(M.getTargetTriple());
switch (TargetTriple.getOS()) {
case Triple::FreeBSD:
switch (TargetTriple.getArch()) {
case Triple::x86_64:
MapParams = FreeBSD_X86_MemoryMapParams.bits64;
break;
case Triple::x86:
MapParams = FreeBSD_X86_MemoryMapParams.bits32;
break;
default:
report_fatal_error("unsupported architecture");
}
break;
case Triple::NetBSD:
switch (TargetTriple.getArch()) {
case Triple::x86_64:
MapParams = NetBSD_X86_MemoryMapParams.bits64;
break;
default:
report_fatal_error("unsupported architecture");
}
break;
case Triple::Linux:
switch (TargetTriple.getArch()) {
case Triple::x86_64:
MapParams = Linux_X86_MemoryMapParams.bits64;
break;
case Triple::x86:
MapParams = Linux_X86_MemoryMapParams.bits32;
break;
case Triple::mips64:
case Triple::mips64el:
MapParams = Linux_MIPS_MemoryMapParams.bits64;
break;
case Triple::ppc64:
case Triple::ppc64le:
MapParams = Linux_PowerPC_MemoryMapParams.bits64;
break;
case Triple::systemz:
MapParams = Linux_S390_MemoryMapParams.bits64;
break;
case Triple::aarch64:
case Triple::aarch64_be:
MapParams = Linux_ARM_MemoryMapParams.bits64;
break;
default:
report_fatal_error("unsupported architecture");
}
break;
default:
report_fatal_error("unsupported operating system");
}
}
C = &(M.getContext());
IRBuilder<> IRB(*C);
IntptrTy = IRB.getIntPtrTy(DL);
OriginTy = IRB.getInt32Ty();
ColdCallWeights = MDBuilder(*C).createBranchWeights(1, 1000);
OriginStoreWeights = MDBuilder(*C).createBranchWeights(1, 1000);
if (!CompileKernel) {
if (TrackOrigins)
M.getOrInsertGlobal("__msan_track_origins", IRB.getInt32Ty(), [&] {
return new GlobalVariable(
M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
IRB.getInt32(TrackOrigins), "__msan_track_origins");
});
if (Recover)
M.getOrInsertGlobal("__msan_keep_going", IRB.getInt32Ty(), [&] {
return new GlobalVariable(M, IRB.getInt32Ty(), true,
GlobalValue::WeakODRLinkage,
IRB.getInt32(Recover), "__msan_keep_going");
});
}
}
bool MemorySanitizerLegacyPass::doInitialization(Module &M) {
if (!Options.Kernel)
insertModuleCtor(M);
MSan.emplace(M, Options);
return true;
}
namespace {
/// 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 {
virtual ~VarArgHelper() = default;
/// Visit a CallBase.
virtual void visitCallBase(CallBase &CB, IRBuilder<> &IRB) = 0;
/// Visit a va_start call.
virtual void visitVAStartInst(VAStartInst &I) = 0;
/// Visit a va_copy call.
virtual void visitVACopyInst(VACopyInst &I) = 0;
/// Finalize function instrumentation.
///
/// This method is called after visiting all interesting (see above)
/// instructions in a function.
virtual void finalizeInstrumentation() = 0;
};
struct MemorySanitizerVisitor;
} // end anonymous namespace
static VarArgHelper *CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
MemorySanitizerVisitor &Visitor);
static unsigned TypeSizeToSizeIndex(unsigned TypeSize) {
if (TypeSize <= 8) return 0;
return Log2_32_Ceil((TypeSize + 7) / 8);
}
namespace {
/// 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;
std::unique_ptr<VarArgHelper> VAHelper;
const TargetLibraryInfo *TLI;
BasicBlock *ActualFnStart;
// The following flags disable parts of MSan instrumentation based on
// blacklist contents and command-line options.
bool InsertChecks;
bool PropagateShadow;
bool PoisonStack;
bool PoisonUndef;
bool CheckReturnValue;
struct ShadowOriginAndInsertPoint {
Value *Shadow;
Value *Origin;
Instruction *OrigIns;
ShadowOriginAndInsertPoint(Value *S, Value *O, Instruction *I)
: Shadow(S), Origin(O), OrigIns(I) {}
};
SmallVector<ShadowOriginAndInsertPoint, 16> InstrumentationList;
bool InstrumentLifetimeStart = ClHandleLifetimeIntrinsics;
SmallSet<AllocaInst *, 16> AllocaSet;
SmallVector<std::pair<IntrinsicInst *, AllocaInst *>, 16> LifetimeStartList;
SmallVector<StoreInst *, 16> StoreList;
MemorySanitizerVisitor(Function &F, MemorySanitizer &MS,
const TargetLibraryInfo &TLI)
: F(F), MS(MS), VAHelper(CreateVarArgHelper(F, MS, *this)), TLI(&TLI) {
bool SanitizeFunction = F.hasFnAttribute(Attribute::SanitizeMemory);
InsertChecks = SanitizeFunction;
PropagateShadow = SanitizeFunction;
PoisonStack = SanitizeFunction && ClPoisonStack;
PoisonUndef = SanitizeFunction && ClPoisonUndef;
// FIXME: Consider using SpecialCaseList to specify a list of functions that
// must always return fully initialized values. For now, we hardcode "main".
CheckReturnValue = SanitizeFunction && (F.getName() == "main");
MS.initializeCallbacks(*F.getParent());
if (MS.CompileKernel)
ActualFnStart = insertKmsanPrologue(F);
else
ActualFnStart = &F.getEntryBlock();
LLVM_DEBUG(if (!InsertChecks) dbgs()
<< "MemorySanitizer is not inserting checks into '"
<< F.getName() << "'\n");
}
Value *updateOrigin(Value *V, IRBuilder<> &IRB) {
if (MS.TrackOrigins <= 1) return V;
return IRB.CreateCall(MS.MsanChainOriginFn, V);
}
Value *originToIntptr(IRBuilder<> &IRB, Value *Origin) {
const DataLayout &DL = F.getParent()->getDataLayout();
unsigned IntptrSize = DL.getTypeStoreSize(MS.IntptrTy);
if (IntptrSize == kOriginSize) return Origin;
assert(IntptrSize == kOriginSize * 2);
Origin = IRB.CreateIntCast(Origin, MS.IntptrTy, /* isSigned */ false);
return IRB.CreateOr(Origin, IRB.CreateShl(Origin, kOriginSize * 8));
}
/// Fill memory range with the given origin value.
void paintOrigin(IRBuilder<> &IRB, Value *Origin, Value *OriginPtr,
unsigned Size, Align Alignment) {
const DataLayout &DL = F.getParent()->getDataLayout();
const Align IntptrAlignment = Align(DL.getABITypeAlignment(MS.IntptrTy));
unsigned IntptrSize = DL.getTypeStoreSize(MS.IntptrTy);
assert(IntptrAlignment >= kMinOriginAlignment);
assert(IntptrSize >= kOriginSize);
unsigned Ofs = 0;
Align CurrentAlignment = Alignment;
if (Alignment >= IntptrAlignment && IntptrSize > kOriginSize) {
Value *IntptrOrigin = originToIntptr(IRB, Origin);
Value *IntptrOriginPtr =
IRB.CreatePointerCast(OriginPtr, PointerType::get(MS.IntptrTy, 0));
for (unsigned i = 0; i < Size / IntptrSize; ++i) {
Value *Ptr = i ? IRB.CreateConstGEP1_32(MS.IntptrTy, IntptrOriginPtr, i)
: IntptrOriginPtr;
IRB.CreateAlignedStore(IntptrOrigin, Ptr, CurrentAlignment);
Ofs += IntptrSize / kOriginSize;
CurrentAlignment = IntptrAlignment;
}
}
for (unsigned i = Ofs; i < (Size + kOriginSize - 1) / kOriginSize; ++i) {
Value *GEP =
i ? IRB.CreateConstGEP1_32(MS.OriginTy, OriginPtr, i) : OriginPtr;
IRB.CreateAlignedStore(Origin, GEP, CurrentAlignment);
CurrentAlignment = kMinOriginAlignment;
}
}
void storeOrigin(IRBuilder<> &IRB, Value *Addr, Value *Shadow, Value *Origin,
Value *OriginPtr, Align Alignment, bool AsCall) {
const DataLayout &DL = F.getParent()->getDataLayout();
const Align OriginAlignment = std::max(kMinOriginAlignment, Alignment);
unsigned StoreSize = DL.getTypeStoreSize(Shadow->getType());
if (Shadow->getType()->isAggregateType()) {
paintOrigin(IRB, updateOrigin(Origin, IRB), OriginPtr, StoreSize,
OriginAlignment);
} else {
Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
if (auto *ConstantShadow = dyn_cast<Constant>(ConvertedShadow)) {
if (ClCheckConstantShadow && !ConstantShadow->isZeroValue())
paintOrigin(IRB, updateOrigin(Origin, IRB), OriginPtr, StoreSize,
OriginAlignment);
return;
}
unsigned TypeSizeInBits =
DL.getTypeSizeInBits(ConvertedShadow->getType());
unsigned SizeIndex = TypeSizeToSizeIndex(TypeSizeInBits);
if (AsCall && SizeIndex < kNumberOfAccessSizes && !MS.CompileKernel) {
FunctionCallee Fn = MS.MaybeStoreOriginFn[SizeIndex];
Value *ConvertedShadow2 = IRB.CreateZExt(
ConvertedShadow, IRB.getIntNTy(8 * (1 << SizeIndex)));
IRB.CreateCall(Fn, {ConvertedShadow2,
IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
Origin});
} else {
Value *Cmp = IRB.CreateICmpNE(
ConvertedShadow, getCleanShadow(ConvertedShadow), "_mscmp");
Instruction *CheckTerm = SplitBlockAndInsertIfThen(
Cmp, &*IRB.GetInsertPoint(), false, MS.OriginStoreWeights);
IRBuilder<> IRBNew(CheckTerm);
paintOrigin(IRBNew, updateOrigin(Origin, IRBNew), OriginPtr, StoreSize,
OriginAlignment);
}
}
}
void materializeStores(bool InstrumentWithCalls) {
for (StoreInst *SI : StoreList) {
IRBuilder<> IRB(SI);
Value *Val = SI->getValueOperand();
Value *Addr = SI->getPointerOperand();
Value *Shadow = SI->isAtomic() ? getCleanShadow(Val) : getShadow(Val);
Value *ShadowPtr, *OriginPtr;
Type *ShadowTy = Shadow->getType();
const Align Alignment = assumeAligned(SI->getAlignment());
const Align OriginAlignment = std::max(kMinOriginAlignment, Alignment);
std::tie(ShadowPtr, OriginPtr) =
getShadowOriginPtr(Addr, IRB, ShadowTy, Alignment, /*isStore*/ true);
StoreInst *NewSI = IRB.CreateAlignedStore(Shadow, ShadowPtr, Alignment);
LLVM_DEBUG(dbgs() << " STORE: " << *NewSI << "\n");
(void)NewSI;
if (SI->isAtomic())
SI->setOrdering(addReleaseOrdering(SI->getOrdering()));
if (MS.TrackOrigins && !SI->isAtomic())
storeOrigin(IRB, Addr, Shadow, getOrigin(Val), OriginPtr,
OriginAlignment, InstrumentWithCalls);
}
}
/// Helper function to insert a warning at IRB's current insert point.
void insertWarningFn(IRBuilder<> &IRB, Value *Origin) {
if (!Origin)
Origin = (Value *)IRB.getInt32(0);
if (MS.CompileKernel) {
IRB.CreateCall(MS.WarningFn, Origin);
} else {
if (MS.TrackOrigins) {
IRB.CreateStore(Origin, MS.OriginTLS);
}
IRB.CreateCall(MS.WarningFn, {});
}
IRB.CreateCall(MS.EmptyAsm, {});
// FIXME: Insert UnreachableInst if !MS.Recover?
// This may invalidate some of the following checks and needs to be done
// at the very end.
}
void materializeOneCheck(Instruction *OrigIns, Value *Shadow, Value *Origin,
bool AsCall) {
IRBuilder<> IRB(OrigIns);
LLVM_DEBUG(dbgs() << " SHAD0 : " << *Shadow << "\n");
Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
LLVM_DEBUG(dbgs() << " SHAD1 : " << *ConvertedShadow << "\n");
if (auto *ConstantShadow = dyn_cast<Constant>(ConvertedShadow)) {
if (ClCheckConstantShadow && !ConstantShadow->isZeroValue()) {
insertWarningFn(IRB, Origin);
}
return;
}
const DataLayout &DL = OrigIns->getModule()->getDataLayout();
unsigned TypeSizeInBits = DL.getTypeSizeInBits(ConvertedShadow->getType());
unsigned SizeIndex = TypeSizeToSizeIndex(TypeSizeInBits);
if (AsCall && SizeIndex < kNumberOfAccessSizes && !MS.CompileKernel) {
FunctionCallee Fn = MS.MaybeWarningFn[SizeIndex];
Value *ConvertedShadow2 =
IRB.CreateZExt(ConvertedShadow, IRB.getIntNTy(8 * (1 << SizeIndex)));
IRB.CreateCall(Fn, {ConvertedShadow2, MS.TrackOrigins && Origin
? Origin
: (Value *)IRB.getInt32(0)});
} else {
Value *Cmp = IRB.CreateICmpNE(ConvertedShadow,
getCleanShadow(ConvertedShadow), "_mscmp");
Instruction *CheckTerm = SplitBlockAndInsertIfThen(
Cmp, OrigIns,
/* Unreachable */ !MS.Recover, MS.ColdCallWeights);
IRB.SetInsertPoint(CheckTerm);
insertWarningFn(IRB, Origin);
LLVM_DEBUG(dbgs() << " CHECK: " << *Cmp << "\n");
}
}
void materializeChecks(bool InstrumentWithCalls) {
for (const auto &ShadowData : InstrumentationList) {
Instruction *OrigIns = ShadowData.OrigIns;
Value *Shadow = ShadowData.Shadow;
Value *Origin = ShadowData.Origin;
materializeOneCheck(OrigIns, Shadow, Origin, InstrumentWithCalls);
}
LLVM_DEBUG(dbgs() << "DONE:\n" << F);
}
BasicBlock *insertKmsanPrologue(Function &F) {
BasicBlock *ret =
SplitBlock(&F.getEntryBlock(), F.getEntryBlock().getFirstNonPHI());
IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
Value *ContextState = IRB.CreateCall(MS.MsanGetContextStateFn, {});
Constant *Zero = IRB.getInt32(0);
MS.ParamTLS = IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
{Zero, IRB.getInt32(0)}, "param_shadow");
MS.RetvalTLS = IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
{Zero, IRB.getInt32(1)}, "retval_shadow");
MS.VAArgTLS = IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
{Zero, IRB.getInt32(2)}, "va_arg_shadow");
MS.VAArgOriginTLS = IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
{Zero, IRB.getInt32(3)}, "va_arg_origin");
MS.VAArgOverflowSizeTLS =
IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
{Zero, IRB.getInt32(4)}, "va_arg_overflow_size");
MS.ParamOriginTLS = IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
{Zero, IRB.getInt32(5)}, "param_origin");
MS.RetvalOriginTLS =
IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
{Zero, IRB.getInt32(6)}, "retval_origin");
return ret;
}
/// Add MemorySanitizer instrumentation to a function.
bool runOnFunction() {
// In the presence of unreachable blocks, we may see Phi nodes with
// incoming nodes from such blocks. Since InstVisitor skips unreachable
// blocks, such nodes will not have any shadow value associated with them.
// It's easier to remove unreachable blocks than deal with missing shadow.
removeUnreachableBlocks(F);
// 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 (BasicBlock *BB : depth_first(ActualFnStart))
visit(*BB);
// Finalize PHI nodes.
for (PHINode *PN : ShadowPHINodes) {
PHINode *PNS = cast<PHINode>(getShadow(PN));
PHINode *PNO = MS.TrackOrigins ? cast<PHINode>(getOrigin(PN)) : nullptr;
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();
// Poison llvm.lifetime.start intrinsics, if we haven't fallen back to
// instrumenting only allocas.
if (InstrumentLifetimeStart) {
for (auto Item : LifetimeStartList) {
instrumentAlloca(*Item.second, Item.first);
AllocaSet.erase(Item.second);
}
}
// Poison the allocas for which we didn't instrument the corresponding
// lifetime intrinsics.
for (AllocaInst *AI : AllocaSet)
instrumentAlloca(*AI);
bool InstrumentWithCalls = ClInstrumentationWithCallThreshold >= 0 &&
InstrumentationList.size() + StoreList.size() >
(unsigned)ClInstrumentationWithCallThreshold;
// Insert shadow value checks.
materializeChecks(InstrumentWithCalls);
// Delayed instrumentation of StoreInst.
// This may not add new address checks.
materializeStores(InstrumentWithCalls);
return true;
}
/// Compute the shadow type that corresponds to a given Value.
Type *getShadowTy(Value *V) {
return getShadowTy(V->getType());
}
/// Compute the shadow type that corresponds to a given Type.
Type *getShadowTy(Type *OrigTy) {
if (!OrigTy->isSized()) {
return nullptr;
}
// 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;
const DataLayout &DL = F.getParent()->getDataLayout();
if (VectorType *VT = dyn_cast<VectorType>(OrigTy)) {
uint32_t EltSize = DL.getTypeSizeInBits(VT->getElementType());
return VectorType::get(IntegerType::get(*MS.C, EltSize),
VT->getNumElements());
}
if (ArrayType *AT = dyn_cast<ArrayType>(OrigTy)) {
return ArrayType::get(getShadowTy(AT->getElementType()),
AT->getNumElements());
}
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());
LLVM_DEBUG(dbgs() << "getShadowTy: " << *ST << " ===> " << *Res << "\n");
return Res;
}
uint32_t TypeSize = DL.getTypeSizeInBits(OrigTy);
return IntegerType::get(*MS.C, TypeSize);
}
/// Flatten a vector type.
Type *getShadowTyNoVec(Type *ty) {
if (VectorType *vt = dyn_cast<VectorType>(ty))
return IntegerType::get(*MS.C,
vt->getPrimitiveSizeInBits().getFixedSize());
return ty;
}
/// 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);
}
/// Compute the integer shadow offset that corresponds to a given
/// application address.
///
/// Offset = (Addr & ~AndMask) ^ XorMask
Value *getShadowPtrOffset(Value *Addr, IRBuilder<> &IRB) {
Value *OffsetLong = IRB.CreatePointerCast(Addr, MS.IntptrTy);
uint64_t AndMask = MS.MapParams->AndMask;
if (AndMask)
OffsetLong =
IRB.CreateAnd(OffsetLong, ConstantInt::get(MS.IntptrTy, ~AndMask));
uint64_t XorMask = MS.MapParams->XorMask;
if (XorMask)
OffsetLong =
IRB.CreateXor(OffsetLong, ConstantInt::get(MS.IntptrTy, XorMask));
return OffsetLong;
}
/// Compute the shadow and origin addresses corresponding to a given
/// application address.
///
/// Shadow = ShadowBase + Offset
/// Origin = (OriginBase + Offset) & ~3ULL
std::pair<Value *, Value *>
getShadowOriginPtrUserspace(Value *Addr, IRBuilder<> &IRB, Type *ShadowTy,
MaybeAlign Alignment) {
Value *ShadowOffset = getShadowPtrOffset(Addr, IRB);
Value *ShadowLong = ShadowOffset;
uint64_t ShadowBase = MS.MapParams->ShadowBase;
if (ShadowBase != 0) {
ShadowLong =
IRB.CreateAdd(ShadowLong,
ConstantInt::get(MS.IntptrTy, ShadowBase));
}
Value *ShadowPtr =
IRB.CreateIntToPtr(ShadowLong, PointerType::get(ShadowTy, 0));
Value *OriginPtr = nullptr;
if (MS.TrackOrigins) {
Value *OriginLong = ShadowOffset;
uint64_t OriginBase = MS.MapParams->OriginBase;
if (OriginBase != 0)
OriginLong = IRB.CreateAdd(OriginLong,
ConstantInt::get(MS.IntptrTy, OriginBase));
if (!Alignment || *Alignment < kMinOriginAlignment) {
uint64_t Mask = kMinOriginAlignment.value() - 1;
OriginLong =
IRB.CreateAnd(OriginLong, ConstantInt::get(MS.IntptrTy, ~Mask));
}
OriginPtr =
IRB.CreateIntToPtr(OriginLong, PointerType::get(MS.OriginTy, 0));
}
return std::make_pair(ShadowPtr, OriginPtr);
}
std::pair<Value *, Value *> getShadowOriginPtrKernel(Value *Addr,
IRBuilder<> &IRB,
Type *ShadowTy,
bool isStore) {
Value *ShadowOriginPtrs;
const DataLayout &DL = F.getParent()->getDataLayout();
int Size = DL.getTypeStoreSize(ShadowTy);
FunctionCallee Getter = MS.getKmsanShadowOriginAccessFn(isStore, Size);
Value *AddrCast =
IRB.CreatePointerCast(Addr, PointerType::get(IRB.getInt8Ty(), 0));
if (Getter) {
ShadowOriginPtrs = IRB.CreateCall(Getter, AddrCast);
} else {
Value *SizeVal = ConstantInt::get(MS.IntptrTy, Size);
ShadowOriginPtrs = IRB.CreateCall(isStore ? MS.MsanMetadataPtrForStoreN
: MS.MsanMetadataPtrForLoadN,
{AddrCast, SizeVal});
}
Value *ShadowPtr = IRB.CreateExtractValue(ShadowOriginPtrs, 0);
ShadowPtr = IRB.CreatePointerCast(ShadowPtr, PointerType::get(ShadowTy, 0));
Value *OriginPtr = IRB.CreateExtractValue(ShadowOriginPtrs, 1);
return std::make_pair(ShadowPtr, OriginPtr);
}
std::pair<Value *, Value *> getShadowOriginPtr(Value *Addr, IRBuilder<> &IRB,
Type *ShadowTy,
MaybeAlign Alignment,
bool isStore) {
if (MS.CompileKernel)
return getShadowOriginPtrKernel(Addr, IRB, ShadowTy, isStore);
return getShadowOriginPtrUserspace(Addr, IRB, ShadowTy, Alignment);
}
/// 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);
if (ArgOffset)
Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A), 0),
"_msarg");
}
/// Compute the origin address for a given function argument.
Value *getOriginPtrForArgument(Value *A, IRBuilder<> &IRB,
int ArgOffset) {
if (!MS.TrackOrigins)
return nullptr;
Value *Base = IRB.CreatePointerCast(MS.ParamOriginTLS, MS.IntptrTy);
if (ArgOffset)
Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
return IRB.CreateIntToPtr(Base, PointerType::get(MS.OriginTy, 0),
"_msarg_o");
}
/// Compute the shadow address for a retval.
Value *getShadowPtrForRetval(Value *A, IRBuilder<> &IRB) {
return IRB.CreatePointerCast(MS.RetvalTLS,
PointerType::get(getShadowTy(A), 0),
"_msret");
}
/// 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;
}
/// 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] = PropagateShadow ? SV : getCleanShadow(V);
}
/// Set Origin to be the origin value for V.
void setOrigin(Value *V, Value *Origin) {
if (!MS.TrackOrigins) return;
assert(!OriginMap.count(V) && "Values may only have one origin");
LLVM_DEBUG(dbgs() << "ORIGIN: " << *V << " ==> " << *Origin << "\n");
OriginMap[V] = Origin;
}
Constant *getCleanShadow(Type *OrigTy) {
Type *ShadowTy = getShadowTy(OrigTy);
if (!ShadowTy)
return nullptr;
return Constant::getNullValue(ShadowTy);
}
/// Create a clean shadow value for a given value.
///
/// Clean shadow (all zeroes) means all bits of the value are defined
/// (initialized).
Constant *getCleanShadow(Value *V) {
return getCleanShadow(V->getType());
}
/// 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);
if (ArrayType *AT = dyn_cast<ArrayType>(ShadowTy)) {
SmallVector<Constant *, 4> Vals(AT->getNumElements(),
getPoisonedShadow(AT->getElementType()));
return ConstantArray::get(AT, Vals);
}
if (StructType *ST = dyn_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);
}
llvm_unreachable("Unexpected shadow type");
}
/// Create a dirty shadow for a given value.
Constant *getPoisonedShadow(Value *V) {
Type *ShadowTy = getShadowTy(V);
if (!ShadowTy)
return nullptr;
return getPoisonedShadow(ShadowTy);
}
/// Create a clean (zero) origin.
Value *getCleanOrigin() {
return Constant::getNullValue(MS.OriginTy);
}
/// 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 (!PropagateShadow) return getCleanShadow(V);
if (Instruction *I = dyn_cast<Instruction>(V)) {
if (I->getMetadata("nosanitize"))
return getCleanShadow(V);
// For instructions the shadow is already stored in the map.
Value *Shadow = ShadowMap[V];
if (!Shadow) {
LLVM_DEBUG(dbgs() << "No shadow: " << *V << "\n" << *(I->getParent()));
(void)I;
assert(Shadow && "No shadow for a value");
}
return Shadow;
}
if (UndefValue *U = dyn_cast<UndefValue>(V)) {
Value *AllOnes = PoisonUndef ? getPoisonedShadow(V) : getCleanShadow(V);
LLVM_DEBUG(dbgs() << "Undef: " << *U << " ==> " << *AllOnes << "\n");
(void)U;
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(ActualFnStart->getFirstNonPHI());
unsigned ArgOffset = 0;
const DataLayout &DL = F->getParent()->getDataLayout();
for (auto &FArg : F->args()) {
if (!FArg.getType()->isSized()) {
LLVM_DEBUG(dbgs() << "Arg is not sized\n");
continue;
}
unsigned Size =
FArg.hasByValAttr()
? DL.getTypeAllocSize(FArg.getType()->getPointerElementType())
: DL.getTypeAllocSize(FArg.getType());
if (A == &FArg) {
bool Overflow = ArgOffset + Size > kParamTLSSize;
Value *Base = getShadowPtrForArgument(&FArg, EntryIRB, ArgOffset);
if (FArg.hasByValAttr()) {
// ByVal pointer itself has clean shadow. We copy the actual
// argument shadow to the underlying memory.
// Figure out maximal valid memcpy alignment.
const Align ArgAlign = DL.getValueOrABITypeAlignment(
MaybeAlign(FArg.getParamAlignment()),
A->getType()->getPointerElementType());
Value *CpShadowPtr =
getShadowOriginPtr(V, EntryIRB, EntryIRB.getInt8Ty(), ArgAlign,
/*isStore*/ true)
.first;
// TODO(glider): need to copy origins.
if (Overflow) {
// ParamTLS overflow.
EntryIRB.CreateMemSet(
CpShadowPtr, Constant::getNullValue(EntryIRB.getInt8Ty()),
Size, ArgAlign);
} else {
const Align CopyAlign = std::min(ArgAlign, kShadowTLSAlignment);
Value *Cpy = EntryIRB.CreateMemCpy(CpShadowPtr, CopyAlign, Base,
CopyAlign, Size);
LLVM_DEBUG(dbgs() << " ByValCpy: " << *Cpy << "\n");
(void)Cpy;
}
*ShadowPtr = getCleanShadow(V);
} else {
if (Overflow) {
// ParamTLS overflow.
*ShadowPtr = getCleanShadow(V);
} else {
*ShadowPtr = EntryIRB.CreateAlignedLoad(getShadowTy(&FArg), Base,
kShadowTLSAlignment);
}
}
LLVM_DEBUG(dbgs()
<< " ARG: " << FArg << " ==> " << **ShadowPtr << "\n");
if (MS.TrackOrigins && !Overflow) {
Value *OriginPtr =
getOriginPtrForArgument(&FArg, EntryIRB, ArgOffset);
setOrigin(A, EntryIRB.CreateLoad(MS.OriginTy, OriginPtr));
} else {
setOrigin(A, getCleanOrigin());
}
}
ArgOffset += alignTo(Size, kShadowTLSAlignment);
}
assert(*ShadowPtr && "Could not find shadow for an argument");
return *ShadowPtr;
}
// For everything else the shadow is zero.
return getCleanShadow(V);
}
/// Get the shadow for i-th argument of the instruction I.
Value *getShadow(Instruction *I, int i) {
return getShadow(I->getOperand(i));
}
/// Get the origin for a value.
Value *getOrigin(Value *V) {
if (!MS.TrackOrigins) return nullptr;
if (!PropagateShadow) return getCleanOrigin();
if (isa<Constant>(V)) return getCleanOrigin();
assert((isa<Instruction>(V) || isa<Argument>(V)) &&
"Unexpected value type in getOrigin()");
if (Instruction *I = dyn_cast<Instruction>(V)) {
if (I->getMetadata("nosanitize"))
return getCleanOrigin();
}
Value *Origin = OriginMap[V];
assert(Origin && "Missing origin");
return Origin;
}
/// Get the origin for i-th argument of the instruction I.
Value *getOrigin(Instruction *I, int i) {
return getOrigin(I->getOperand(i));
}
/// 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 shadow value is not 0.
void insertShadowCheck(Value *Shadow, Value *Origin, Instruction *OrigIns) {
assert(Shadow);
if (!InsertChecks) return;
#ifndef NDEBUG
Type *ShadowTy = Shadow->getType();
assert((isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy)) &&
"Can only insert checks for integer and vector shadow types");
#endif
InstrumentationList.push_back(
ShadowOriginAndInsertPoint(Shadow, Origin, OrigIns));
}
/// 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 insertShadowCheck(Value *Val, Instruction *OrigIns) {
assert(Val);
Value *Shadow, *Origin;
if (ClCheckConstantShadow) {
Shadow = getShadow(Val);
if (!Shadow) return;
Origin = getOrigin(Val);
} else {
Shadow = dyn_cast_or_null<Instruction>(getShadow(Val));
if (!Shadow) return;
Origin = dyn_cast_or_null<Instruction>(getOrigin(Val));
}
insertShadowCheck(Shadow, Origin, OrigIns);
}
AtomicOrdering addReleaseOrdering(AtomicOrdering a) {
switch (a) {
case AtomicOrdering::NotAtomic:
return AtomicOrdering::NotAtomic;
case AtomicOrdering::Unordered:
case AtomicOrdering::Monotonic:
case AtomicOrdering::Release:
return AtomicOrdering::Release;
case AtomicOrdering::Acquire:
case AtomicOrdering::AcquireRelease:
return AtomicOrdering::AcquireRelease;
case AtomicOrdering::SequentiallyConsistent:
return AtomicOrdering::SequentiallyConsistent;
}
llvm_unreachable("Unknown ordering");
}
AtomicOrdering addAcquireOrdering(AtomicOrdering a) {
switch (a) {
case AtomicOrdering::NotAtomic:
return AtomicOrdering::NotAtomic;
case AtomicOrdering::Unordered:
case AtomicOrdering::Monotonic:
case AtomicOrdering::Acquire:
return AtomicOrdering::Acquire;
case AtomicOrdering::Release:
case AtomicOrdering::AcquireRelease:
return AtomicOrdering::AcquireRelease;
case AtomicOrdering::SequentiallyConsistent:
return AtomicOrdering::SequentiallyConsistent;
}
llvm_unreachable("Unknown ordering");
}
// ------------------- Visitors.
using InstVisitor<MemorySanitizerVisitor>::visit;
void visit(Instruction &I) {
if (!I.getMetadata("nosanitize"))
InstVisitor<MemorySanitizerVisitor>::visit(I);
}
/// Instrument LoadInst
///
/// Loads the corresponding shadow and (optionally) origin.
/// Optionally, checks that the load address is fully defined.
void visitLoadInst(LoadInst &I) {
assert(I.getType()->isSized() && "Load type must have size");
assert(!I.getMetadata("nosanitize"));
IRBuilder<> IRB(I.getNextNode());
Type *ShadowTy = getShadowTy(&I);
Value *Addr = I.getPointerOperand();
Value *ShadowPtr = nullptr, *OriginPtr = nullptr;
const Align Alignment = assumeAligned(I.getAlignment());
if (PropagateShadow) {
std::tie(ShadowPtr, OriginPtr) =
getShadowOriginPtr(Addr, IRB, ShadowTy, Alignment, /*isStore*/ false);
setShadow(&I,
IRB.CreateAlignedLoad(ShadowTy, ShadowPtr, Alignment, "_msld"));
} else {
setShadow(&I, getCleanShadow(&I));
}
if (ClCheckAccessAddress)
insertShadowCheck(I.getPointerOperand(), &I);
if (I.isAtomic())
I.setOrdering(addAcquireOrdering(I.getOrdering()));
if (MS.TrackOrigins) {
if (PropagateShadow) {
const Align OriginAlignment = std::max(kMinOriginAlignment, Alignment);
setOrigin(
&I, IRB.CreateAlignedLoad(MS.OriginTy, OriginPtr, OriginAlignment));
} else {
setOrigin(&I, getCleanOrigin());
}
}
}
/// Instrument StoreInst
///
/// Stores the corresponding shadow and (optionally) origin.
/// Optionally, checks that the store address is fully defined.
void visitStoreInst(StoreInst &I) {
StoreList.push_back(&I);
if (ClCheckAccessAddress)
insertShadowCheck(I.getPointerOperand(), &I);
}
void handleCASOrRMW(Instruction &I) {
assert(isa<AtomicRMWInst>(I) || isa<AtomicCmpXchgInst>(I));
IRBuilder<> IRB(&I);
Value *Addr = I.getOperand(0);
Value *ShadowPtr = getShadowOriginPtr(Addr, IRB, I.getType(), Align(1),
/*isStore*/ true)
.first;
if (ClCheckAccessAddress)
insertShadowCheck(Addr, &I);
// Only test the conditional argument of cmpxchg instruction.
// The other argument can potentially be uninitialized, but we can not
// detect this situation reliably without possible false positives.
if (isa<AtomicCmpXchgInst>(I))
insertShadowCheck(I.getOperand(1), &I);
IRB.CreateStore(getCleanShadow(&I), ShadowPtr);
setShadow(&I, getCleanShadow(&I));
setOrigin(&I, getCleanOrigin());
}
void visitAtomicRMWInst(AtomicRMWInst &I) {
handleCASOrRMW(I);
I.setOrdering(addReleaseOrdering(I.getOrdering()));
}
void visitAtomicCmpXchgInst(AtomicCmpXchgInst &I) {
handleCASOrRMW(I);
I.setSuccessOrdering(addReleaseOrdering(I.getSuccessOrdering()));
}
// Vector manipulation.
void visitExtractElementInst(ExtractElementInst &I) {
insertShadowCheck(I.getOperand(1), &I);
IRBuilder<> IRB(&I);
setShadow(&I, IRB.CreateExtractElement(getShadow(&I, 0), I.getOperand(1),
"_msprop"));
setOrigin(&I, getOrigin(&I, 0));
}
void visitInsertElementInst(InsertElementInst &I) {
insertShadowCheck(I.getOperand(2), &I);
IRBuilder<> IRB(&I);
setShadow(&I, IRB.CreateInsertElement(getShadow(&I, 0), getShadow(&I, 1),
I.getOperand(2), "_msprop"));
setOriginForNaryOp(I);
}
void visitShuffleVectorInst(ShuffleVectorInst &I) {
IRBuilder<> IRB(&I);
setShadow(&I, IRB.CreateShuffleVector(getShadow(&I, 0), getShadow(&I, 1),
I.getShuffleMask(), "_msprop"));
setOriginForNaryOp(I);
}
// 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) {
// Special case: if this is the bitcast (there is exactly 1 allowed) between
// a musttail call and a ret, don't instrument. New instructions are not
// allowed after a musttail call.
if (auto *CI = dyn_cast<CallInst>(I.getOperand(0)))
if (CI->isMustTailCall())
return;
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); }
/// 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, 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, V1S2, S1V2}));
setOriginForNaryOp(I);
}
/// Default propagation of shadow and/or origin.
///
/// This class implements the general case of shadow propagation, used in all
/// cases where we don't know and/or don't 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.
///
/// This class also implements the general case of origin propagation. For a
/// Nary operation, result origin is set to the origin of an argument that is
/// not entirely initialized. If there is more than one such arguments, the
/// rightmost of them is picked. It does not matter which one is picked if all
/// arguments are initialized.
template <bool CombineShadow>
class Combiner {
Value *Shadow = nullptr;
Value *Origin = nullptr;
IRBuilder<> &IRB;
MemorySanitizerVisitor *MSV;
public:
Combiner(MemorySanitizerVisitor *MSV, IRBuilder<> &IRB)
: IRB(IRB), MSV(MSV) {}
/// Add a pair of shadow and origin values to the mix.
Combiner &Add(Value *OpShadow, Value *OpOrigin) {
if (CombineShadow) {
assert(OpShadow);
if (!Shadow)
Shadow = OpShadow;
else {
OpShadow = MSV->CreateShadowCast(IRB, OpShadow, Shadow->getType());
Shadow = IRB.CreateOr(Shadow, OpShadow, "_msprop");
}
}
if (MSV->MS.TrackOrigins) {
assert(OpOrigin);
if (!Origin) {
Origin = OpOrigin;
} else {
Constant *ConstOrigin = dyn_cast<Constant>(OpOrigin);
// No point in adding something that might result in 0 origin value.
if (!ConstOrigin || !ConstOrigin->isNullValue()) {
Value *FlatShadow = MSV->convertToShadowTyNoVec(OpShadow, IRB);
Value *Cond =
IRB.CreateICmpNE(FlatShadow, MSV->getCleanShadow(FlatShadow));
Origin = IRB.CreateSelect(Cond, OpOrigin, Origin);
}
}
}
return *this;
}
/// Add an application value to the mix.
Combiner &Add(Value *V) {
Value *OpShadow = MSV->getShadow(V);
Value *OpOrigin = MSV->MS.TrackOrigins ? MSV->getOrigin(V) : nullptr;
return Add(OpShadow, OpOrigin);
}
/// Set the current combined values as the given instruction's shadow
/// and origin.
void Done(Instruction *I) {
if (CombineShadow) {
assert(Shadow);
Shadow = MSV->CreateShadowCast(IRB, Shadow, MSV->getShadowTy(I));
MSV->setShadow(I, Shadow);
}
if (MSV->MS.TrackOrigins) {
assert(Origin);
MSV->setOrigin(I, Origin);
}
}
};
using ShadowAndOriginCombiner = Combiner<true>;
using OriginCombiner = Combiner<false>;
/// Propagate origin for arbitrary operation.
void setOriginForNaryOp(Instruction &I) {
if (!MS.TrackOrigins) return;
IRBuilder<> IRB(&I);
OriginCombiner OC(this, IRB);
for (Instruction::op_iterator OI = I.op_begin(); OI != I.op_end(); ++OI)
OC.Add(OI->get());
OC.Done(&I);
}
size_t VectorOrPrimitiveTypeSizeInBits(Type *Ty) {
assert(!(Ty->isVectorTy() && Ty->getScalarType()->isPointerTy()) &&
"Vector of pointers is not a valid shadow type");
return Ty->isVectorTy() ? cast<VectorType>(Ty)->getNumElements() *
Ty->getScalarSizeInBits()
: Ty->getPrimitiveSizeInBits();
}
/// Cast between two shadow types, extending or truncating as
/// necessary.
Value *CreateShadowCast(IRBuilder<> &IRB, Value *V, Type *dstTy,
bool Signed = false) {
Type *srcTy = V->getType();
size_t srcSizeInBits = VectorOrPrimitiveTypeSizeInBits(srcTy);
size_t dstSizeInBits = VectorOrPrimitiveTypeSizeInBits(dstTy);
if (srcSizeInBits > 1 && dstSizeInBits == 1)
return IRB.CreateICmpNE(V, getCleanShadow(V));
if (dstTy->isIntegerTy() && srcTy->isIntegerTy())
return IRB.CreateIntCast(V, dstTy, Signed);
if (dstTy->isVectorTy() && srcTy->isVectorTy() &&
cast<VectorType>(dstTy)->getNumElements() ==
cast<VectorType>(srcTy)->getNumElements())
return IRB.CreateIntCast(V, dstTy, Signed);
Value *V1 = IRB.CreateBitCast(V, Type::getIntNTy(*MS.C, srcSizeInBits));
Value *V2 =
IRB.CreateIntCast(V1, Type::getIntNTy(*MS.C, dstSizeInBits), Signed);
return IRB.CreateBitCast(V2, dstTy);
// TODO: handle struct types.
}
/// Cast an application value to the type of its own shadow.
Value *CreateAppToShadowCast(IRBuilder<> &IRB, Value *V) {
Type *ShadowTy = getShadowTy(V);
if (V->getType() == ShadowTy)
return V;
if (V->getType()->isPtrOrPtrVectorTy())
return IRB.CreatePtrToInt(V, ShadowTy);
else
return IRB.CreateBitCast(V, ShadowTy);
}
/// Propagate shadow for arbitrary operation.
void handleShadowOr(Instruction &I) {
IRBuilder<> IRB(&I);
ShadowAndOriginCombiner SC(this, IRB);
for (Instruction::op_iterator OI = I.op_begin(); OI != I.op_end(); ++OI)
SC.Add(OI->get());
SC.Done(&I);
}
void visitFNeg(UnaryOperator &I) { handleShadowOr(I); }
// Handle multiplication by constant.
//
// Handle a special case of multiplication by constant that may have one or
// more zeros in the lower bits. This makes corresponding number of lower bits
// of the result zero as well. We model it by shifting the other operand
// shadow left by the required number of bits. Effectively, we transform
// (X * (A * 2**B)) to ((X << B) * A) and instrument (X << B) as (Sx << B).
// We use multiplication by 2**N instead of shift to cover the case of
// multiplication by 0, which may occur in some elements of a vector operand.
void handleMulByConstant(BinaryOperator &I, Constant *ConstArg,
Value *OtherArg) {
Constant *ShadowMul;
Type *Ty = ConstArg->getType();
if (auto *VTy = dyn_cast<VectorType>(Ty)) {
unsigned NumElements = VTy->getNumElements();
Type *EltTy = VTy->getElementType();
SmallVector<Constant *, 16> Elements;
for (unsigned Idx = 0; Idx < NumElements; ++Idx) {
if (ConstantInt *Elt =
dyn_cast<ConstantInt>(ConstArg->getAggregateElement(Idx))) {
const APInt &V = Elt->getValue();
APInt V2 = APInt(V.getBitWidth(), 1) << V.countTrailingZeros();
Elements.push_back(ConstantInt::get(EltTy, V2));
} else {
Elements.push_back(ConstantInt::get(EltTy, 1));
}
}
ShadowMul = ConstantVector::get(Elements);
} else {
if (ConstantInt *Elt = dyn_cast<ConstantInt>(ConstArg)) {
const APInt &V = Elt->getValue();
APInt V2 = APInt(V.getBitWidth(), 1) << V.countTrailingZeros();
ShadowMul = ConstantInt::get(Ty, V2);
} else {
ShadowMul = ConstantInt::get(Ty, 1);
}
}
IRBuilder<> IRB(&I);
setShadow(&I,
IRB.CreateMul(getShadow(OtherArg), ShadowMul, "msprop_mul_cst"));
setOrigin(&I, getOrigin(OtherArg));
}
void visitMul(BinaryOperator &I) {
Constant *constOp0 = dyn_cast<Constant>(I.getOperand(0));
Constant *constOp1 = dyn_cast<Constant>(I.getOperand(1));
if (constOp0 && !constOp1)
handleMulByConstant(I, constOp0, I.getOperand(1));
else if (constOp1 && !constOp0)
handleMulByConstant(I, constOp1, I.getOperand(0));
else
handleShadowOr(I);
}
void visitFAdd(BinaryOperator &I) { handleShadowOr(I); }
void visitFSub(BinaryOperator &I) { handleShadowOr(I); }
void visitFMul(BinaryOperator &I) { handleShadowOr(I); }
void visitAdd(BinaryOperator &I) { handleShadowOr(I); }
void visitSub(BinaryOperator &I) { handleShadowOr(I); }
void visitXor(BinaryOperator &I) { handleShadowOr(I); }
void handleIntegerDiv(Instruction &I) {
IRBuilder<> IRB(&I);
// Strict on the second argument.
insertShadowCheck(I.getOperand(1), &I);
setShadow(&I, getShadow(&I, 0));
setOrigin(&I, getOrigin(&I, 0));
}
void visitUDiv(BinaryOperator &I) { handleIntegerDiv(I); }
void visitSDiv(BinaryOperator &I) { handleIntegerDiv(I); }
void visitURem(BinaryOperator &I) { handleIntegerDiv(I); }
void visitSRem(BinaryOperator &I) { handleIntegerDiv(I); }
// Floating point division is side-effect free. We can not require that the
// divisor is fully initialized and must propagate shadow. See PR37523.
void visitFDiv(BinaryOperator &I) { handleShadowOr(I); }
void visitFRem(BinaryOperator &I) { handleShadowOr(I); }
/// 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);
// Get rid of pointers and vectors of pointers.
// For ints (and vectors of ints), types of A and Sa match,
// and this is a no-op.
A = IRB.CreatePointerCast(A, Sa->getType());
B = IRB.CreatePointerCast(B, Sb->getType());
// 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);
}
/// Build the lowest possible value of V, taking into account V's
/// uninitialized bits.
Value *getLowestPossibleValue(IRBuilder<> &IRB, Value *A, Value *Sa,
bool isSigned) {
if (isSigned) {
// Split shadow into sign bit and other bits.
Value *SaOtherBits = IRB.CreateLShr(IRB.CreateShl(Sa, 1), 1);
Value *SaSignBit = IRB.CreateXor(Sa, SaOtherBits);
// Maximise the undefined shadow bit, minimize other undefined bits.
return
IRB.CreateOr(IRB.CreateAnd(A, IRB.CreateNot(SaOtherBits)), SaSignBit);
} else {
// Minimize undefined bits.
return IRB.CreateAnd(A, IRB.CreateNot(Sa));
}
}
/// Build the highest possible value of V, taking into account V's
/// uninitialized bits.
Value *getHighestPossibleValue(IRBuilder<> &IRB, Value *A, Value *Sa,
bool isSigned) {
if (isSigned) {
// Split shadow into sign bit and other bits.
Value *SaOtherBits = IRB.CreateLShr(IRB.CreateShl(Sa, 1), 1);
Value *SaSignBit = IRB.CreateXor(Sa, SaOtherBits);
// Minimise the undefined shadow bit, maximise other undefined bits.
return
IRB.CreateOr(IRB.CreateAnd(A, IRB.CreateNot(SaSignBit)), SaOtherBits);
} else {
// Maximize undefined bits.
return IRB.CreateOr(A, Sa);
}
}
/// Instrument relational comparisons.
///
/// This function does exact shadow propagation for all relational
/// comparisons of integers, pointers and vectors of those.
/// FIXME: output seems suboptimal when one of the operands is a constant
void handleRelationalComparisonExact(ICmpInst &I) {
IRBuilder<> IRB(&I);
Value *A = I.getOperand(0);
Value *B = I.getOperand(1);
Value *Sa = getShadow(A);
Value *Sb = getShadow(B);
// Get rid of pointers and vectors of pointers.
// For ints (and vectors of ints), types of A and Sa match,
// and this is a no-op.
A = IRB.CreatePointerCast(A, Sa->getType());
B = IRB.CreatePointerCast(B, Sb->getType());
// Let [a0, a1] be the interval of possible values of A, taking into account
// its undefined bits. Let [b0, b1] be the interval of possible values of B.
// Then (A cmp B) is defined iff (a0 cmp b1) == (a1 cmp b0).
bool IsSigned = I.isSigned();
Value *S1 = IRB.CreateICmp(I.getPredicate(),
getLowestPossibleValue(IRB, A, Sa, IsSigned),
getHighestPossibleValue(IRB, B, Sb, IsSigned));
Value *S2 = IRB.CreateICmp(I.getPredicate(),
getHighestPossibleValue(IRB, A, Sa, IsSigned),
getLowestPossibleValue(IRB, B, Sb, IsSigned));
Value *Si = IRB.CreateXor(S1, S2);
setShadow(&I, Si);
setOriginForNaryOp(I);
}
/// Instrument signed relational comparisons.
///
/// Handle sign bit tests: x<0, x>=0, x<=-1, x>-1 by propagating the highest
/// bit of the shadow. Everything else is delegated to handleShadowOr().
void handleSignedRelationalComparison(ICmpInst &I) {
Constant *constOp;
Value *op = nullptr;
CmpInst::Predicate pre;
if ((constOp = dyn_cast<Constant>(I.getOperand(1)))) {
op = I.getOperand(0);
pre = I.getPredicate();
} else if ((constOp = dyn_cast<Constant>(I.getOperand(0)))) {
op = I.getOperand(1);
pre = I.getSwappedPredicate();
} else {
handleShadowOr(I);
return;
}
if ((constOp->isNullValue() &&
(pre == CmpInst::ICMP_SLT || pre == CmpInst::ICMP_SGE)) ||
(constOp->isAllOnesValue() &&
(pre == CmpInst::ICMP_SGT || pre == CmpInst::ICMP_SLE))) {
IRBuilder<> IRB(&I);
Value *Shadow = IRB.CreateICmpSLT(getShadow(op), getCleanShadow(op),
"_msprop_icmp_s");
setShadow(&I, Shadow);
setOrigin(&I, getOrigin(op));
} else {
handleShadowOr(I);
}
}
void visitICmpInst(ICmpInst &I) {
if (!ClHandleICmp) {
handleShadowOr(I);
return;
}
if (I.isEquality()) {
handleEqualityComparison(I);
return;
}
assert(I.isRelational());
if (ClHandleICmpExact) {
handleRelationalComparisonExact(I);
return;
}
if (I.isSigned()) {
handleSignedRelationalComparison(I);
return;
}
assert(I.isUnsigned());
if ((isa<Constant>(I.getOperand(0)) || isa<Constant>(I.getOperand(1)))) {
handleRelationalComparisonExact(I);
return;
}
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); }
/// 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.
void visitMemMoveInst(MemMoveInst &I) {
IRBuilder<> IRB(&I);
IRB.CreateCall(
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();
}
// Similar to memmove: avoid copying shadow twice.
// This is somewhat unfortunate as it may slowdown small constant memcpys.
// FIXME: consider doing manual inline for small constant sizes and proper
// alignment.
void visitMemCpyInst(MemCpyInst &I) {
IRBuilder<> IRB(&I);
IRB.CreateCall(
MS.MemcpyFn,
{IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
IRB.CreatePointerCast(I.getArgOperand(1), IRB.getInt8PtrTy()),
IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false)});
I.eraseFromParent();
}
// Same as memcpy.
void visitMemSetInst(MemSetInst &I) {
IRBuilder<> IRB(&I);
IRB.CreateCall(
MS.MemsetFn,
{IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
IRB.CreateIntCast(I.getArgOperand(1), IRB.getInt32Ty(), false),
IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false)});
I.eraseFromParent();
}
void visitVAStartInst(VAStartInst &I) {
VAHelper->visitVAStartInst(I);
}
void visitVACopyInst(VACopyInst &I) {
VAHelper->visitVACopyInst(I);
}
/// Handle vector store-like intrinsics.
///
/// Instrument intrinsics that look like a simple SIMD store: writes memory,
/// has 1 pointer argument and 1 vector argument, returns void.
bool handleVectorStoreIntrinsic(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Value* Addr = I.getArgOperand(0);
Value *Shadow = getShadow(&I, 1);
Value *ShadowPtr, *OriginPtr;
// We don't know the pointer alignment (could be unaligned SSE store!).
// Have to assume to worst case.
std::tie(ShadowPtr, OriginPtr) = getShadowOriginPtr(
Addr, IRB, Shadow->getType(), Align(1), /*isStore*/ true);
IRB.CreateAlignedStore(Shadow, ShadowPtr, Align(1));
if (ClCheckAccessAddress)
insertShadowCheck(Addr, &I);
// FIXME: factor out common code from materializeStores
if (MS.TrackOrigins) IRB.CreateStore(getOrigin(&I, 1), OriginPtr);
return true;
}
/// Handle vector load-like intrinsics.
///
/// Instrument intrinsics that look like a simple SIMD load: reads memory,
/// has 1 pointer argument, returns a vector.
bool handleVectorLoadIntrinsic(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Value *Addr = I.getArgOperand(0);
Type *ShadowTy = getShadowTy(&I);
Value *ShadowPtr = nullptr, *OriginPtr = nullptr;
if (PropagateShadow) {
// We don't know the pointer alignment (could be unaligned SSE load!).
// Have to assume to worst case.
const Align Alignment = Align(1);
std::tie(ShadowPtr, OriginPtr) =
getShadowOriginPtr(Addr, IRB, ShadowTy, Alignment, /*isStore*/ false);
setShadow(&I,
IRB.CreateAlignedLoad(ShadowTy, ShadowPtr, Alignment, "_msld"));
} else {
setShadow(&I, getCleanShadow(&I));
}
if (ClCheckAccessAddress)
insertShadowCheck(Addr, &I);
if (MS.TrackOrigins) {
if (PropagateShadow)
setOrigin(&I, IRB.CreateLoad(MS.OriginTy, OriginPtr));
else
setOrigin(&I, getCleanOrigin());
}
return true;
}
/// Handle (SIMD arithmetic)-like intrinsics.
///
/// Instrument intrinsics with any number of arguments of the same type,
/// equal to the return type. The type should be simple (no aggregates or
/// pointers; vectors are fine).
/// Caller guarantees that this intrinsic does not access memory.
bool maybeHandleSimpleNomemIntrinsic(IntrinsicInst &I) {
Type *RetTy = I.getType();
if (!(RetTy->isIntOrIntVectorTy() ||
RetTy->isFPOrFPVectorTy() ||
RetTy->isX86_MMXTy()))
return false;
unsigned NumArgOperands = I.getNumArgOperands();
for (unsigned i = 0; i < NumArgOperands; ++i) {
Type *Ty = I.getArgOperand(i)->getType();
if (Ty != RetTy)
return false;
}
IRBuilder<> IRB(&I);
ShadowAndOriginCombiner SC(this, IRB);
for (unsigned i = 0; i < NumArgOperands; ++i)
SC.Add(I.getArgOperand(i));
SC.Done(&I);
return true;
}
/// Heuristically instrument unknown intrinsics.
///
/// The main purpose of this code is to do something reasonable with all
/// random intrinsics we might encounter, most importantly - SIMD intrinsics.
/// We recognize several classes of intrinsics by their argument types and
/// ModRefBehaviour and apply special instrumentation when we are reasonably
/// sure that we know what the intrinsic does.
///
/// We special-case intrinsics where this approach fails. See llvm.bswap
/// handling as an example of that.
bool handleUnknownIntrinsic(IntrinsicInst &I) {
unsigned NumArgOperands = I.getNumArgOperands();
if (NumArgOperands == 0)
return false;
if (NumArgOperands == 2 &&
I.getArgOperand(0)->getType()->isPointerTy() &&
I.getArgOperand(1)->getType()->isVectorTy() &&
I.getType()->isVoidTy() &&
!I.onlyReadsMemory()) {
// This looks like a vector store.
return handleVectorStoreIntrinsic(I);
}
if (NumArgOperands == 1 &&
I.getArgOperand(0)->getType()->isPointerTy() &&
I.getType()->isVectorTy() &&
I.onlyReadsMemory()) {
// This looks like a vector load.
return handleVectorLoadIntrinsic(I);
}
if (I.doesNotAccessMemory())
if (maybeHandleSimpleNomemIntrinsic(I))
return true;
// FIXME: detect and handle SSE maskstore/maskload
return false;
}
void handleInvariantGroup(IntrinsicInst &I) {
setShadow(&I, getShadow(&I, 0));
setOrigin(&I, getOrigin(&I, 0));
}
void handleLifetimeStart(IntrinsicInst &I) {
if (!PoisonStack)
return;
DenseMap<Value *, AllocaInst *> AllocaForValue;
AllocaInst *AI =
llvm::findAllocaForValue(I.getArgOperand(1), AllocaForValue);
if (!AI)
InstrumentLifetimeStart = false;
LifetimeStartList.push_back(std::make_pair(&I, AI));
}
void handleBswap(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Value *Op = I.getArgOperand(0);
Type *OpType = Op->getType();
Function *BswapFunc = Intrinsic::getDeclaration(
F.getParent(), Intrinsic::bswap, makeArrayRef(&OpType, 1));
setShadow(&I, IRB.CreateCall(BswapFunc, getShadow(Op)));
setOrigin(&I, getOrigin(Op));
}
// Instrument vector convert intrinsic.
//
// This function instruments intrinsics like cvtsi2ss:
// %Out = int_xxx_cvtyyy(%ConvertOp)
// or
// %Out = int_xxx_cvtyyy(%CopyOp, %ConvertOp)
// Intrinsic converts \p NumUsedElements elements of \p ConvertOp to the same
// number \p Out elements, and (if has 2 arguments) copies the rest of the
// elements from \p CopyOp.
// In most cases conversion involves floating-point value which may trigger a
// hardware exception when not fully initialized. For this reason we require
// \p ConvertOp[0:NumUsedElements] to be fully initialized and trap otherwise.
// We copy the shadow of \p CopyOp[NumUsedElements:] to \p
// Out[NumUsedElements:]. This means that intrinsics without \p CopyOp always
// return a fully initialized value.
void handleVectorConvertIntrinsic(IntrinsicInst &I, int NumUsedElements) {
IRBuilder<> IRB(&I);
Value *CopyOp, *ConvertOp;
switch (I.getNumArgOperands()) {
case 3:
assert(isa<ConstantInt>(I.getArgOperand(2)) && "Invalid rounding mode");
LLVM_FALLTHROUGH;
case 2:
CopyOp = I.getArgOperand(0);
ConvertOp = I.getArgOperand(1);
break;
case 1:
ConvertOp = I.getArgOperand(0);
CopyOp = nullptr;
break;
default:
llvm_unreachable("Cvt intrinsic with unsupported number of arguments.");
}
// The first *NumUsedElements* elements of ConvertOp are converted to the
// same number of output elements. The rest of the output is copied from
// CopyOp, or (if not available) filled with zeroes.
// Combine shadow for elements of ConvertOp that are used in this operation,
// and insert a check.
// FIXME: consider propagating shadow of ConvertOp, at least in the case of
// int->any conversion.
Value *ConvertShadow = getShadow(ConvertOp);
Value *AggShadow = nullptr;
if (ConvertOp->getType()->isVectorTy()) {
AggShadow = IRB.CreateExtractElement(
ConvertShadow, ConstantInt::get(IRB.getInt32Ty(), 0));
for (int i = 1; i < NumUsedElements; ++i) {
Value *MoreShadow = IRB.CreateExtractElement(
ConvertShadow, ConstantInt::get(IRB.getInt32Ty(), i));
AggShadow = IRB.CreateOr(AggShadow, MoreShadow);
}
} else {
AggShadow = ConvertShadow;
}
assert(AggShadow->getType()->isIntegerTy());
insertShadowCheck(AggShadow, getOrigin(ConvertOp), &I);
// Build result shadow by zero-filling parts of CopyOp shadow that come from
// ConvertOp.
if (CopyOp) {
assert(CopyOp->getType() == I.getType());
assert(CopyOp->getType()->isVectorTy());
Value *ResultShadow = getShadow(CopyOp);
Type *EltTy = cast<VectorType>(ResultShadow->getType())->getElementType();
for (int i = 0; i < NumUsedElements; ++i) {
ResultShadow = IRB.CreateInsertElement(
ResultShadow, ConstantInt::getNullValue(EltTy),
ConstantInt::get(IRB.getInt32Ty(), i));
}
setShadow(&I, ResultShadow);
setOrigin(&I, getOrigin(CopyOp));
} else {
setShadow(&I, getCleanShadow(&I));
setOrigin(&I, getCleanOrigin());
}
}
// Given a scalar or vector, extract lower 64 bits (or less), and return all
// zeroes if it is zero, and all ones otherwise.
Value *Lower64ShadowExtend(IRBuilder<> &IRB, Value *S, Type *T) {
if (S->getType()->isVectorTy())
S = CreateShadowCast(IRB, S, IRB.getInt64Ty(), /* Signed */ true);
assert(S->getType()->getPrimitiveSizeInBits() <= 64);
Value *S2 = IRB.CreateICmpNE(S, getCleanShadow(S));
return CreateShadowCast(IRB, S2, T, /* Signed */ true);
}
// Given a vector, extract its first element, and return all
// zeroes if it is zero, and all ones otherwise.
Value *LowerElementShadowExtend(IRBuilder<> &IRB, Value *S, Type *T) {
Value *S1 = IRB.CreateExtractElement(S, (uint64_t)0);
Value *S2 = IRB.CreateICmpNE(S1, getCleanShadow(S1));
return CreateShadowCast(IRB, S2, T, /* Signed */ true);
}
Value *VariableShadowExtend(IRBuilder<> &IRB, Value *S) {
Type *T = S->getType();
assert(T->isVectorTy());
Value *S2 = IRB.CreateICmpNE(S, getCleanShadow(S));
return IRB.CreateSExt(S2, T);
}
// Instrument vector shift intrinsic.
//
// This function instruments intrinsics like int_x86_avx2_psll_w.
// Intrinsic shifts %In by %ShiftSize bits.
// %ShiftSize may be a vector. In that case the lower 64 bits determine shift
// size, and the rest is ignored. Behavior is defined even if shift size is
// greater than register (or field) width.
void handleVectorShiftIntrinsic(IntrinsicInst &I, bool Variable) {
assert(I.getNumArgOperands() == 2);
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 = Variable ? VariableShadowExtend(IRB, S2)
: Lower64ShadowExtend(IRB, S2, getShadowTy(&I));
Value *V1 = I.getOperand(0);
Value *V2 = I.getOperand(1);
Value *Shift = IRB.CreateCall(I.getFunctionType(), I.getCalledValue(),
{IRB.CreateBitCast(S1, V1->getType()), V2});
Shift = IRB.CreateBitCast(Shift, getShadowTy(&I));
setShadow(&I, IRB.CreateOr(Shift, S2Conv));
setOriginForNaryOp(I);
}
// Get an X86_MMX-sized vector type.
Type *getMMXVectorTy(unsigned EltSizeInBits) {
const unsigned X86_MMXSizeInBits = 64;
assert(EltSizeInBits != 0 && (X86_MMXSizeInBits % EltSizeInBits) == 0 &&
"Illegal MMX vector element size");
return VectorType::get(IntegerType::get(*MS.C, EltSizeInBits),
X86_MMXSizeInBits / EltSizeInBits);
}
// Returns a signed counterpart for an (un)signed-saturate-and-pack
// intrinsic.
Intrinsic::ID getSignedPackIntrinsic(Intrinsic::ID id) {
switch (id) {
case Intrinsic::x86_sse2_packsswb_128:
case Intrinsic::x86_sse2_packuswb_128:
return Intrinsic::x86_sse2_packsswb_128;
case Intrinsic::x86_sse2_packssdw_128:
case Intrinsic::x86_sse41_packusdw:
return Intrinsic::x86_sse2_packssdw_128;
case Intrinsic::x86_avx2_packsswb:
case Intrinsic::x86_avx2_packuswb:
return Intrinsic::x86_avx2_packsswb;
case Intrinsic::x86_avx2_packssdw:
case Intrinsic::x86_avx2_packusdw:
return Intrinsic::x86_avx2_packssdw;
case Intrinsic::x86_mmx_packsswb:
case Intrinsic::x86_mmx_packuswb:
return Intrinsic::x86_mmx_packsswb;
case Intrinsic::x86_mmx_packssdw:
return Intrinsic::x86_mmx_packssdw;
default:
llvm_unreachable("unexpected intrinsic id");
}
}
// Instrument vector pack intrinsic.
//
// This function instruments intrinsics like x86_mmx_packsswb, that
// packs elements of 2 input vectors into half as many bits with saturation.
// Shadow is propagated with the signed variant of the same intrinsic applied
// to sext(Sa != zeroinitializer), sext(Sb != zeroinitializer).
// EltSizeInBits is used only for x86mmx arguments.
void handleVectorPackIntrinsic(IntrinsicInst &I, unsigned EltSizeInBits = 0) {
assert(I.getNumArgOperands() == 2);
bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
IRBuilder<> IRB(&I);
Value *S1 = getShadow(&I, 0);
Value *S2 = getShadow(&I, 1);
assert(isX86_MMX || S1->getType()->isVectorTy());
// SExt and ICmpNE below must apply to individual elements of input vectors.
// In case of x86mmx arguments, cast them to appropriate vector types and
// back.
Type *T = isX86_MMX ? getMMXVectorTy(EltSizeInBits) : S1->getType();
if (isX86_MMX) {
S1 = IRB.CreateBitCast(S1, T);
S2 = IRB.CreateBitCast(S2, T);
}
Value *S1_ext = IRB.CreateSExt(
IRB.CreateICmpNE(S1, Constant::getNullValue(T)), T);
Value *S2_ext = IRB.CreateSExt(
IRB.CreateICmpNE(S2, Constant::getNullValue(T)), T);
if (isX86_MMX) {
Type *X86_MMXTy = Type::getX86_MMXTy(*MS.C);
S1_ext = IRB.CreateBitCast(S1_ext, X86_MMXTy);
S2_ext = IRB.CreateBitCast(S2_ext, X86_MMXTy);
}
Function *ShadowFn = Intrinsic::getDeclaration(
F.getParent(), getSignedPackIntrinsic(I.getIntrinsicID()));
Value *S =
IRB.CreateCall(ShadowFn, {S1_ext, S2_ext}, "_msprop_vector_pack");
if (isX86_MMX) S = IRB.CreateBitCast(S, getShadowTy(&I));
setShadow(&I, S);
setOriginForNaryOp(I);
}
// Instrument sum-of-absolute-differences intrinsic.
void handleVectorSadIntrinsic(IntrinsicInst &I) {
const unsigned SignificantBitsPerResultElement = 16;
bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
Type *ResTy = isX86_MMX ? IntegerType::get(*MS.C, 64) : I.getType();
unsigned ZeroBitsPerResultElement =
ResTy->getScalarSizeInBits() - SignificantBitsPerResultElement;
IRBuilder<> IRB(&I);
Value *S = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
S = IRB.CreateBitCast(S, ResTy);
S = IRB.CreateSExt(IRB.CreateICmpNE(S, Constant::getNullValue(ResTy)),
ResTy);
S = IRB.CreateLShr(S, ZeroBitsPerResultElement);
S = IRB.CreateBitCast(S, getShadowTy(&I));
setShadow(&I, S);
setOriginForNaryOp(I);
}
// Instrument multiply-add intrinsic.
void handleVectorPmaddIntrinsic(IntrinsicInst &I,
unsigned EltSizeInBits = 0) {
bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
Type *ResTy = isX86_MMX ? getMMXVectorTy(EltSizeInBits * 2) : I.getType();
IRBuilder<> IRB(&I);
Value *S = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
S = IRB.CreateBitCast(S, ResTy);
S = IRB.CreateSExt(IRB.CreateICmpNE(S, Constant::getNullValue(ResTy)),
ResTy);
S = IRB.CreateBitCast(S, getShadowTy(&I));
setShadow(&I, S);
setOriginForNaryOp(I);
}
// Instrument compare-packed intrinsic.
// Basically, an or followed by sext(icmp ne 0) to end up with all-zeros or
// all-ones shadow.
void handleVectorComparePackedIntrinsic(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Type *ResTy = getShadowTy(&I);
Value *S0 = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
Value *S = IRB.CreateSExt(
IRB.CreateICmpNE(S0, Constant::getNullValue(ResTy)), ResTy);
setShadow(&I, S);
setOriginForNaryOp(I);
}
// Instrument compare-scalar intrinsic.
// This handles both cmp* intrinsics which return the result in the first
// element of a vector, and comi* which return the result as i32.
void handleVectorCompareScalarIntrinsic(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Value *S0 = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
Value *S = LowerElementShadowExtend(IRB, S0, getShadowTy(&I));
setShadow(&I, S);
setOriginForNaryOp(I);
}
void handleStmxcsr(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Value* Addr = I.getArgOperand(0);
Type *Ty = IRB.getInt32Ty();
Value *ShadowPtr =
getShadowOriginPtr(Addr, IRB, Ty, Align(1), /*isStore*/ true).first;
IRB.CreateStore(getCleanShadow(Ty),
IRB.CreatePointerCast(ShadowPtr, Ty->getPointerTo()));
if (ClCheckAccessAddress)
insertShadowCheck(Addr, &I);
}
void handleLdmxcsr(IntrinsicInst &I) {
if (!InsertChecks) return;
IRBuilder<> IRB(&I);
Value *Addr = I.getArgOperand(0);
Type *Ty = IRB.getInt32Ty();
const Align Alignment = Align(1);
Value *ShadowPtr, *OriginPtr;
std::tie(ShadowPtr, OriginPtr) =
getShadowOriginPtr(Addr, IRB, Ty, Alignment, /*isStore*/ false);
if (ClCheckAccessAddress)
insertShadowCheck(Addr, &I);
Value *Shadow = IRB.CreateAlignedLoad(Ty, ShadowPtr, Alignment, "_ldmxcsr");
Value *Origin = MS.TrackOrigins ? IRB.CreateLoad(MS.OriginTy, OriginPtr)
: getCleanOrigin();
insertShadowCheck(Shadow, Origin, &I);
}
void handleMaskedStore(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Value *V = I.getArgOperand(0);
Value *Addr = I.getArgOperand(1);
const Align Alignment(
cast<ConstantInt>(I.getArgOperand(2))->getZExtValue());
Value *Mask = I.getArgOperand(3);
Value *Shadow = getShadow(V);
Value *ShadowPtr;
Value *OriginPtr;
std::tie(ShadowPtr, OriginPtr) = getShadowOriginPtr(
Addr, IRB, Shadow->getType(), Alignment, /*isStore*/ true);
if (ClCheckAccessAddress) {
insertShadowCheck(Addr, &I);
// Uninitialized mask is kind of like uninitialized address, but not as
// scary.
insertShadowCheck(Mask, &I);
}
IRB.CreateMaskedStore(Shadow, ShadowPtr, Alignment, Mask);
if (MS.TrackOrigins) {
auto &DL = F.getParent()->getDataLayout();
paintOrigin(IRB, getOrigin(V), OriginPtr,
DL.getTypeStoreSize(Shadow->getType()),
std::max(Alignment, kMinOriginAlignment));
}
}
bool handleMaskedLoad(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Value *Addr = I.getArgOperand(0);
const Align Alignment(
cast<ConstantInt>(I.getArgOperand(1))->getZExtValue());
Value *Mask = I.getArgOperand(2);
Value *PassThru = I.getArgOperand(3);
Type *ShadowTy = getShadowTy(&I);
Value *ShadowPtr, *OriginPtr;
if (PropagateShadow) {
std::tie(ShadowPtr, OriginPtr) =
getShadowOriginPtr(Addr, IRB, ShadowTy, Alignment, /*isStore*/ false);
setShadow(&I, IRB.CreateMaskedLoad(ShadowPtr, Alignment, Mask,
getShadow(PassThru), "_msmaskedld"));
} else {
setShadow(&I, getCleanShadow(&I));
}
if (ClCheckAccessAddress) {
insertShadowCheck(Addr, &I);
insertShadowCheck(Mask, &I);
}
if (MS.TrackOrigins) {
if (PropagateShadow) {
// Choose between PassThru's and the loaded value's origins.
Value *MaskedPassThruShadow = IRB.CreateAnd(
getShadow(PassThru), IRB.CreateSExt(IRB.CreateNeg(Mask), ShadowTy));
Value *Acc = IRB.CreateExtractElement(
MaskedPassThruShadow, ConstantInt::get(IRB.getInt32Ty(), 0));
for (int i = 1,
N = cast<VectorType>(PassThru->getType())->getNumElements();
i < N; ++i) {
Value *More = IRB.CreateExtractElement(
MaskedPassThruShadow, ConstantInt::get(IRB.getInt32Ty(), i));
Acc = IRB.CreateOr(Acc, More);
}
Value *Origin = IRB.CreateSelect(
IRB.CreateICmpNE(Acc, Constant::getNullValue(Acc->getType())),
getOrigin(PassThru), IRB.CreateLoad(MS.OriginTy, OriginPtr));
setOrigin(&I, Origin);
} else {
setOrigin(&I, getCleanOrigin());
}
}
return true;
}
// Instrument BMI / BMI2 intrinsics.
// All of these intrinsics are Z = I(X, Y)
// where the types of all operands and the result match, and are either i32 or i64.
// The following instrumentation happens to work for all of them:
// Sz = I(Sx, Y) | (sext (Sy != 0))
void handleBmiIntrinsic(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Type *ShadowTy = getShadowTy(&I);
// If any bit of the mask operand is poisoned, then the whole thing is.
Value *SMask = getShadow(&I, 1);
SMask = IRB.CreateSExt(IRB.CreateICmpNE(SMask, getCleanShadow(ShadowTy)),
ShadowTy);
// Apply the same intrinsic to the shadow of the first operand.
Value *S = IRB.CreateCall(I.getCalledFunction(),
{getShadow(&I, 0), I.getOperand(1)});
S = IRB.CreateOr(SMask, S);
setShadow(&I, S);
setOriginForNaryOp(I);
}
SmallVector<int, 8> getPclmulMask(unsigned Width, bool OddElements) {
SmallVector<int, 8> Mask;
for (unsigned X = OddElements ? 1 : 0; X < Width; X += 2) {
Mask.append(2, X);
}
return Mask;
}
// Instrument pclmul intrinsics.
// These intrinsics operate either on odd or on even elements of the input
// vectors, depending on the constant in the 3rd argument, ignoring the rest.
// Replace the unused elements with copies of the used ones, ex:
// (0, 1, 2, 3) -> (0, 0, 2, 2) (even case)
// or
// (0, 1, 2, 3) -> (1, 1, 3, 3) (odd case)
// and then apply the usual shadow combining logic.
void handlePclmulIntrinsic(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Type *ShadowTy = getShadowTy(&I);
unsigned Width =
cast<VectorType>(I.getArgOperand(0)->getType())->getNumElements();
assert(isa<ConstantInt>(I.getArgOperand(2)) &&
"pclmul 3rd operand must be a constant");
unsigned Imm = cast<ConstantInt>(I.getArgOperand(2))->getZExtValue();
Value *Shuf0 =
IRB.CreateShuffleVector(getShadow(&I, 0), UndefValue::get(ShadowTy),
getPclmulMask(Width, Imm & 0x01));
Value *Shuf1 =
IRB.CreateShuffleVector(getShadow(&I, 1), UndefValue::get(ShadowTy),
getPclmulMask(Width, Imm & 0x10));
ShadowAndOriginCombiner SOC(this, IRB);
SOC.Add(Shuf0, getOrigin(&I, 0));
SOC.Add(Shuf1, getOrigin(&I, 1));
SOC.Done(&I);
}
void visitIntrinsicInst(IntrinsicInst &I) {
switch (I.getIntrinsicID()) {
case Intrinsic::lifetime_start:
handleLifetimeStart(I);
break;
case Intrinsic::launder_invariant_group:
case Intrinsic::strip_invariant_group:
handleInvariantGroup(I);
break;
case Intrinsic::bswap:
handleBswap(I);
break;
case Intrinsic::masked_store:
handleMaskedStore(I);
break;
case Intrinsic::masked_load:
handleMaskedLoad(I);
break;
case Intrinsic::x86_sse_stmxcsr:
handleStmxcsr(I);
break;
case Intrinsic::x86_sse_ldmxcsr:
handleLdmxcsr(I);
break;
case Intrinsic::x86_avx512_vcvtsd2usi64:
case Intrinsic::x86_avx512_vcvtsd2usi32:
case Intrinsic::x86_avx512_vcvtss2usi64:
case Intrinsic::x86_avx512_vcvtss2usi32:
case Intrinsic::x86_avx512_cvttss2usi64:
case Intrinsic::x86_avx512_cvttss2usi:
case Intrinsic::x86_avx512_cvttsd2usi64:
case Intrinsic::x86_avx512_cvttsd2usi:
case Intrinsic::x86_avx512_cvtusi2ss:
case Intrinsic::x86_avx512_cvtusi642sd:
case Intrinsic::x86_avx512_cvtusi642ss:
case Intrinsic::x86_sse2_cvtsd2si64:
case Intrinsic::x86_sse2_cvtsd2si:
case Intrinsic::x86_sse2_cvtsd2ss:
case Intrinsic::x86_sse2_cvttsd2si64:
case Intrinsic::x86_sse2_cvttsd2si:
case Intrinsic::x86_sse_cvtss2si64:
case Intrinsic::x86_sse_cvtss2si:
case Intrinsic::x86_sse_cvttss2si64:
case Intrinsic::x86_sse_cvttss2si:
handleVectorConvertIntrinsic(I, 1);
break;
case Intrinsic::x86_sse_cvtps2pi:
case Intrinsic::x86_sse_cvttps2pi:
handleVectorConvertIntrinsic(I, 2);
break;
case Intrinsic::x86_avx512_psll_w_512:
case Intrinsic::x86_avx512_psll_d_512:
case Intrinsic::x86_avx512_psll_q_512:
case Intrinsic::x86_avx512_pslli_w_512:
case Intrinsic::x86_avx512_pslli_d_512:
case Intrinsic::x86_avx512_pslli_q_512:
case Intrinsic::x86_avx512_psrl_w_512:
case Intrinsic::x86_avx512_psrl_d_512:
case Intrinsic::x86_avx512_psrl_q_512:
case Intrinsic::x86_avx512_psra_w_512:
case Intrinsic::x86_avx512_psra_d_512:
case Intrinsic::x86_avx512_psra_q_512:
case Intrinsic::x86_avx512_psrli_w_512:
case Intrinsic::x86_avx512_psrli_d_512:
case Intrinsic::x86_avx512_psrli_q_512:
case Intrinsic::x86_avx512_psrai_w_512:
case Intrinsic::x86_avx512_psrai_d_512:
case Intrinsic::x86_avx512_psrai_q_512:
case Intrinsic::x86_avx512_psra_q_256:
case Intrinsic::x86_avx512_psra_q_128:
case Intrinsic::x86_avx512_psrai_q_256:
case Intrinsic::x86_avx512_psrai_q_128:
case Intrinsic::x86_avx2_psll_w:
case Intrinsic::x86_avx2_psll_d:
case Intrinsic::x86_avx2_psll_q:
case Intrinsic::x86_avx2_pslli_w:
case Intrinsic::x86_avx2_pslli_d:
case Intrinsic::x86_avx2_pslli_q:
case Intrinsic::x86_avx2_psrl_w:
case Intrinsic::x86_avx2_psrl_d:
case Intrinsic::x86_avx2_psrl_q:
case Intrinsic::x86_avx2_psra_w:
case Intrinsic::x86_avx2_psra_d:
case Intrinsic::x86_avx2_psrli_w:
case Intrinsic::x86_avx2_psrli_d:
case Intrinsic::x86_avx2_psrli_q:
case Intrinsic::x86_avx2_psrai_w:
case Intrinsic::x86_avx2_psrai_d:
case Intrinsic::x86_sse2_psll_w:
case Intrinsic::x86_sse2_psll_d:
case Intrinsic::x86_sse2_psll_q:
case Intrinsic::x86_sse2_pslli_w:
case Intrinsic::x86_sse2_pslli_d:
case Intrinsic::x86_sse2_pslli_q:
case Intrinsic::x86_sse2_psrl_w:
case Intrinsic::x86_sse2_psrl_d:
case Intrinsic::x86_sse2_psrl_q:
case Intrinsic::x86_sse2_psra_w:
case Intrinsic::x86_sse2_psra_d:
case Intrinsic::x86_sse2_psrli_w:
case Intrinsic::x86_sse2_psrli_d:
case Intrinsic::x86_sse2_psrli_q:
case Intrinsic::x86_sse2_psrai_w:
case Intrinsic::x86_sse2_psrai_d:
case Intrinsic::x86_mmx_psll_w:
case Intrinsic::x86_mmx_psll_d:
case Intrinsic::x86_mmx_psll_q:
case Intrinsic::x86_mmx_pslli_w:
case Intrinsic::x86_mmx_pslli_d:
case Intrinsic::x86_mmx_pslli_q:
case Intrinsic::x86_mmx_psrl_w:
case Intrinsic::x86_mmx_psrl_d:
case Intrinsic::x86_mmx_psrl_q:
case Intrinsic::x86_mmx_psra_w:
case Intrinsic::x86_mmx_psra_d:
case Intrinsic::x86_mmx_psrli_w:
case Intrinsic::x86_mmx_psrli_d:
case Intrinsic::x86_mmx_psrli_q:
case Intrinsic::x86_mmx_psrai_w:
case Intrinsic::x86_mmx_psrai_d:
handleVectorShiftIntrinsic(I, /* Variable */ false);
break;
case Intrinsic::x86_avx2_psllv_d:
case Intrinsic::x86_avx2_psllv_d_256:
case Intrinsic::x86_avx512_psllv_d_512:
case Intrinsic::x86_avx2_psllv_q:
case Intrinsic::x86_avx2_psllv_q_256:
case Intrinsic::x86_avx512_psllv_q_512:
case Intrinsic::x86_avx2_psrlv_d:
case Intrinsic::x86_avx2_psrlv_d_256:
case Intrinsic::x86_avx512_psrlv_d_512:
case Intrinsic::x86_avx2_psrlv_q:
case Intrinsic::x86_avx2_psrlv_q_256:
case Intrinsic::x86_avx512_psrlv_q_512:
case Intrinsic::x86_avx2_psrav_d:
case Intrinsic::x86_avx2_psrav_d_256:
case Intrinsic::x86_avx512_psrav_d_512:
case Intrinsic::x86_avx512_psrav_q_128:
case Intrinsic::x86_avx512_psrav_q_256:
case Intrinsic::x86_avx512_psrav_q_512:
handleVectorShiftIntrinsic(I, /* Variable */ true);
break;
case Intrinsic::x86_sse2_packsswb_128:
case Intrinsic::x86_sse2_packssdw_128:
case Intrinsic::x86_sse2_packuswb_128:
case Intrinsic::x86_sse41_packusdw:
case Intrinsic::x86_avx2_packsswb:
case Intrinsic::x86_avx2_packssdw:
case Intrinsic::x86_avx2_packuswb:
case Intrinsic::x86_avx2_packusdw:
handleVectorPackIntrinsic(I);
break;
case Intrinsic::x86_mmx_packsswb:
case Intrinsic::x86_mmx_packuswb:
handleVectorPackIntrinsic(I, 16);
break;
case Intrinsic::x86_mmx_packssdw:
handleVectorPackIntrinsic(I, 32);
break;
case Intrinsic::x86_mmx_psad_bw:
case Intrinsic::x86_sse2_psad_bw:
case Intrinsic::x86_avx2_psad_bw:
handleVectorSadIntrinsic(I);
break;
case Intrinsic::x86_sse2_pmadd_wd:
case Intrinsic::x86_avx2_pmadd_wd:
case Intrinsic::x86_ssse3_pmadd_ub_sw_128:
case Intrinsic::x86_avx2_pmadd_ub_sw:
handleVectorPmaddIntrinsic(I);
break;
case Intrinsic::x86_ssse3_pmadd_ub_sw:
handleVectorPmaddIntrinsic(I, 8);
break;
case Intrinsic::x86_mmx_pmadd_wd:
handleVectorPmaddIntrinsic(I, 16);
break;
case Intrinsic::x86_sse_cmp_ss:
case Intrinsic::x86_sse2_cmp_sd:
case Intrinsic::x86_sse_comieq_ss:
case Intrinsic::x86_sse_comilt_ss:
case Intrinsic::x86_sse_comile_ss:
case Intrinsic::x86_sse_comigt_ss:
case Intrinsic::x86_sse_comige_ss:
case Intrinsic::x86_sse_comineq_ss:
case Intrinsic::x86_sse_ucomieq_ss:
case Intrinsic::x86_sse_ucomilt_ss:
case Intrinsic::x86_sse_ucomile_ss:
case Intrinsic::x86_sse_ucomigt_ss:
case Intrinsic::x86_sse_ucomige_ss:
case Intrinsic::x86_sse_ucomineq_ss:
case Intrinsic::x86_sse2_comieq_sd:
case Intrinsic::x86_sse2_comilt_sd:
case Intrinsic::x86_sse2_comile_sd:
case Intrinsic::x86_sse2_comigt_sd:
case Intrinsic::x86_sse2_comige_sd:
case Intrinsic::x86_sse2_comineq_sd:
case Intrinsic::x86_sse2_ucomieq_sd:
case Intrinsic::x86_sse2_ucomilt_sd:
case Intrinsic::x86_sse2_ucomile_sd:
case Intrinsic::x86_sse2_ucomigt_sd:
case Intrinsic::x86_sse2_ucomige_sd:
case Intrinsic::x86_sse2_ucomineq_sd:
handleVectorCompareScalarIntrinsic(I);
break;
case Intrinsic::x86_sse_cmp_ps:
case Intrinsic::x86_sse2_cmp_pd:
// FIXME: For x86_avx_cmp_pd_256 and x86_avx_cmp_ps_256 this function
// generates reasonably looking IR that fails in the backend with "Do not
// know how to split the result of this operator!".
handleVectorComparePackedIntrinsic(I);
break;
case Intrinsic::x86_bmi_bextr_32:
case Intrinsic::x86_bmi_bextr_64:
case Intrinsic::x86_bmi_bzhi_32:
case Intrinsic::x86_bmi_bzhi_64:
case Intrinsic::x86_bmi_pdep_32:
case Intrinsic::x86_bmi_pdep_64:
case Intrinsic::x86_bmi_pext_32:
case Intrinsic::x86_bmi_pext_64:
handleBmiIntrinsic(I);
break;
case Intrinsic::x86_pclmulqdq:
case Intrinsic::x86_pclmulqdq_256:
case Intrinsic::x86_pclmulqdq_512:
handlePclmulIntrinsic(I);
break;
case Intrinsic::is_constant:
// The result of llvm.is.constant() is always defined.
setShadow(&I, getCleanShadow(&I));
setOrigin(&I, getCleanOrigin());
break;
default:
if (!handleUnknownIntrinsic(I))
visitInstruction(I);
break;
}
}
void visitCallBase(CallBase &CB) {
assert(!CB.getMetadata("nosanitize"));
if (CB.isInlineAsm()) {
// For inline asm (either a call to asm function, or callbr instruction),
// do the usual thing: check argument shadow and mark all outputs as
// clean. Note that any side effects of the inline asm that are not
// immediately visible in its constraints are not handled.
if (ClHandleAsmConservative && MS.CompileKernel)
visitAsmInstruction(CB);
else
visitInstruction(CB);
return;
}
if (auto *Call = dyn_cast<CallInst>(&CB)) {
assert(!isa<IntrinsicInst>(Call) && "intrinsics are handled elsewhere");
// We are going to insert code that relies on the fact that the callee
// will become a non-readonly function after it is instrumented by us. To
// prevent this code from being optimized out, mark that function
// non-readonly in advance.
if (Function *Func = Call->getCalledFunction()) {
// Clear out readonly/readnone attributes.
AttrBuilder B;
B.addAttribute(Attribute::ReadOnly)
.addAttribute(Attribute::ReadNone)
.addAttribute(Attribute::WriteOnly)
.addAttribute(Attribute::ArgMemOnly)
.addAttribute(Attribute::Speculatable);
Func->removeAttributes(AttributeList::FunctionIndex, B);
}
maybeMarkSanitizerLibraryCallNoBuiltin(Call, TLI);
}
IRBuilder<> IRB(&CB);
unsigned ArgOffset = 0;
LLVM_DEBUG(dbgs() << " CallSite: " << CB << "\n");
for (auto ArgIt = CB.arg_begin(), End = CB.arg_end(); ArgIt != End;
++ArgIt) {
Value *A = *ArgIt;
unsigned i = ArgIt - CB.arg_begin();
if (!A->getType()->isSized()) {
LLVM_DEBUG(dbgs() << "Arg " << i << " is not sized: " << CB << "\n");
continue;
}
unsigned Size = 0;
Value *Store = nullptr;
// 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);
LLVM_DEBUG(dbgs() << " Arg#" << i << ": " << *A
<< " Shadow: " << *ArgShadow << "\n");
bool ArgIsInitialized = false;
const DataLayout &DL = F.getParent()->getDataLayout();
if (CB.paramHasAttr(i, Attribute::ByVal)) {
assert(A->getType()->isPointerTy() &&
"ByVal argument is not a pointer!");
Size = DL.getTypeAllocSize(A->getType()->getPointerElementType());
if (ArgOffset + Size > kParamTLSSize) break;
const MaybeAlign ParamAlignment(CB.getParamAlign(i));
MaybeAlign Alignment = llvm::None;
if (ParamAlignment)
Alignment = std::min(*ParamAlignment, kShadowTLSAlignment);
Value *AShadowPtr =
getShadowOriginPtr(A, IRB, IRB.getInt8Ty(), Alignment,
/*isStore*/ false)
.first;
Store = IRB.CreateMemCpy(ArgShadowBase, Alignment, AShadowPtr,
Alignment, Size);
// TODO(glider): need to copy origins.
} else {
Size = DL.getTypeAllocSize(A->getType());
if (ArgOffset + Size > kParamTLSSize) break;
Store = IRB.CreateAlignedStore(ArgShadow, ArgShadowBase,
kShadowTLSAlignment);
Constant *Cst = dyn_cast<Constant>(ArgShadow);
if (Cst && Cst->isNullValue()) ArgIsInitialized = true;
}
if (MS.TrackOrigins && !ArgIsInitialized)
IRB.CreateStore(getOrigin(A),
getOriginPtrForArgument(A, IRB, ArgOffset));
(void)Store;
assert(Size != 0 && Store != nullptr);
LLVM_DEBUG(dbgs() << " Param:" << *Store << "\n");
ArgOffset += alignTo(Size, 8);
}
LLVM_DEBUG(dbgs() << " done with call args\n");
FunctionType *FT = CB.getFunctionType();
if (FT->isVarArg()) {
VAHelper->visitCallBase(CB, IRB);
}
// Now, get the shadow for the RetVal.
if (!CB.getType()->isSized())
return;
// Don't emit the epilogue for musttail call returns.
if (isa<CallInst>(CB) && cast<CallInst>(CB).isMustTailCall())
return;
IRBuilder<> IRBBefore(&CB);
// Until we have full dynamic coverage, make sure the retval shadow is 0.
Value *Base = getShadowPtrForRetval(&CB, IRBBefore);
IRBBefore.CreateAlignedStore(getCleanShadow(&CB), Base,
kShadowTLSAlignment);
BasicBlock::iterator NextInsn;
if (isa<CallInst>(CB)) {
NextInsn = ++CB.getIterator();
assert(NextInsn != CB.getParent()->end());
} else {
BasicBlock *NormalDest = cast<InvokeInst>(CB).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(&CB, getCleanShadow(&CB));
setOrigin(&CB, getCleanOrigin());
return;
}
// FIXME: NextInsn is likely in a basic block that has not been visited yet.
// Anything inserted there will be instrumented by MSan later!
NextInsn = NormalDest->getFirstInsertionPt();
assert(NextInsn != NormalDest->end() &&
"Could not find insertion point for retval shadow load");
}
IRBuilder<> IRBAfter(&*NextInsn);
Value *RetvalShadow = IRBAfter.CreateAlignedLoad(
getShadowTy(&CB), getShadowPtrForRetval(&CB, IRBAfter),
kShadowTLSAlignment, "_msret");
setShadow(&CB, RetvalShadow);
if (MS.TrackOrigins)
setOrigin(&CB, IRBAfter.CreateLoad(MS.OriginTy,
getOriginPtrForRetval(IRBAfter)));
}
bool isAMustTailRetVal(Value *RetVal) {
if (auto *I = dyn_cast<BitCastInst>(RetVal)) {
RetVal = I->getOperand(0);
}
if (auto *I = dyn_cast<CallInst>(RetVal)) {
return I->isMustTailCall();
}
return false;
}
void visitReturnInst(ReturnInst &I) {
IRBuilder<> IRB(&I);
Value *RetVal = I.getReturnValue();
if (!RetVal) return;
// Don't emit the epilogue for musttail call returns.
if (isAMustTailRetVal(RetVal)) return;
Value *ShadowPtr = getShadowPtrForRetval(RetVal, IRB);
if (CheckReturnValue) {
insertShadowCheck(RetVal, &I);
Value *Shadow = getCleanShadow(RetVal);
IRB.CreateAlignedStore(Shadow, ShadowPtr, kShadowTLSAlignment);
} else {
Value *Shadow = getShadow(RetVal);
IRB.CreateAlignedStore(Shadow, ShadowPtr, kShadowTLSAlignment);
if (MS.TrackOrigins)
IRB.CreateStore(getOrigin(RetVal), getOriginPtrForRetval(IRB));
}
}
void visitPHINode(PHINode &I) {
IRBuilder<> IRB(&I);
if (!PropagateShadow) {
setShadow(&I, getCleanShadow(&I));
setOrigin(&I, getCleanOrigin());
return;
}
ShadowPHINodes.push_back(&I);
setShadow(&I, IRB.CreatePHI(getShadowTy(&I), I.getNumIncomingValues(),
"_msphi_s"));
if (MS.TrackOrigins)
setOrigin(&I, IRB.CreatePHI(MS.OriginTy, I.getNumIncomingValues(),
"_msphi_o"));
}
Value *getLocalVarDescription(AllocaInst &I) {
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();
return createPrivateNonConstGlobalForString(*F.getParent(),
StackDescription.str());
}
void poisonAllocaUserspace(AllocaInst &I, IRBuilder<> &IRB, Value *Len) {
if (PoisonStack && ClPoisonStackWithCall) {
IRB.CreateCall(MS.MsanPoisonStackFn,
{IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()), Len});
} else {
Value *ShadowBase, *OriginBase;
std::tie(ShadowBase, OriginBase) = getShadowOriginPtr(
&I, IRB, IRB.getInt8Ty(), Align(1), /*isStore*/ true);
Value *PoisonValue = IRB.getInt8(PoisonStack ? ClPoisonStackPattern : 0);
IRB.CreateMemSet(ShadowBase, PoisonValue, Len,
MaybeAlign(I.getAlignment()));
}
if (PoisonStack && MS.TrackOrigins) {
Value *Descr = getLocalVarDescription(I);
IRB.CreateCall(MS.MsanSetAllocaOrigin4Fn,
{IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()), Len,
IRB.CreatePointerCast(Descr, IRB.getInt8PtrTy()),
IRB.CreatePointerCast(&F, MS.IntptrTy)});
}
}
void poisonAllocaKmsan(AllocaInst &I, IRBuilder<> &IRB, Value *Len) {
Value *Descr = getLocalVarDescription(I);
if (PoisonStack) {
IRB.CreateCall(MS.MsanPoisonAllocaFn,
{IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()), Len,
IRB.CreatePointerCast(Descr, IRB.getInt8PtrTy())});
} else {
IRB.CreateCall(MS.MsanUnpoisonAllocaFn,
{IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()), Len});
}
}
void instrumentAlloca(AllocaInst &I, Instruction *InsPoint = nullptr) {
if (!InsPoint)
InsPoint = &I;
IRBuilder<> IRB(InsPoint->getNextNode());
const DataLayout &DL = F.getParent()->getDataLayout();
uint64_t TypeSize = DL.getTypeAllocSize(I.getAllocatedType());
Value *Len = ConstantInt::get(MS.IntptrTy, TypeSize);
if (I.isArrayAllocation())
Len = IRB.CreateMul(Len, I.getArraySize());
if (MS.CompileKernel)
poisonAllocaKmsan(I, IRB, Len);
else
poisonAllocaUserspace(I, IRB, Len);
}
void visitAllocaInst(AllocaInst &I) {
setShadow(&I, getCleanShadow(&I));
setOrigin(&I, getCleanOrigin());
// We'll get to this alloca later unless it's poisoned at the corresponding
// llvm.lifetime.start.
AllocaSet.insert(&I);
}
void visitSelectInst(SelectInst& I) {
IRBuilder<> IRB(&I);
// a = select b, c, d
Value *B = I.getCondition();
Value *C = I.getTrueValue();
Value *D = I.getFalseValue();
Value *Sb = getShadow(B);
Value *Sc = getShadow(C);
Value *Sd = getShadow(D);
// Result shadow if condition shadow is 0.
Value *Sa0 = IRB.CreateSelect(B, Sc, Sd);
Value *Sa1;
if (I.getType()->isAggregateType()) {
// To avoid "sign extending" i1 to an arbitrary aggregate type, we just do
// an extra "select". This results in much more compact IR.
// Sa = select Sb, poisoned, (select b, Sc, Sd)
Sa1 = getPoisonedShadow(getShadowTy(I.getType()));
} else {
// Sa = select Sb, [ (c^d) | Sc | Sd ], [ b ? Sc : Sd ]
// If Sb (condition is poisoned), look for bits in c and d that are equal
// and both unpoisoned.
// If !Sb (condition is unpoisoned), simply pick one of Sc and Sd.
// Cast arguments to shadow-compatible type.
C = CreateAppToShadowCast(IRB, C);
D = CreateAppToShadowCast(IRB, D);
// Result shadow if condition shadow is 1.
Sa1 = IRB.CreateOr({IRB.CreateXor(C, D), Sc, Sd});
}
Value *Sa = IRB.CreateSelect(Sb, Sa1, Sa0, "_msprop_select");
setShadow(&I, Sa);
if (MS.TrackOrigins) {
// Origins are always i32, so any vector conditions must be flattened.
// FIXME: consider tracking vector origins for app vectors?
if (B->getType()->isVectorTy()) {
Type *FlatTy = getShadowTyNoVec(B->getType());
B = IRB.CreateICmpNE(IRB.CreateBitCast(B, FlatTy),
ConstantInt::getNullValue(FlatTy));
Sb = IRB.CreateICmpNE(IRB.CreateBitCast(Sb, FlatTy),
ConstantInt::getNullValue(FlatTy));
}
// a = select b, c, d
// Oa = Sb ? Ob : (b ? Oc : Od)
setOrigin(
&I, IRB.CreateSelect(Sb, getOrigin(I.getCondition()),
IRB.CreateSelect(B, getOrigin(I.getTrueValue()),
getOrigin(I.getFalseValue()))));
}
}
void visitLandingPadInst(LandingPadInst &I) {
// Do nothing.
// See https://github.com/google/sanitizers/issues/504
setShadow(&I, getCleanShadow(&I));
setOrigin(&I, getCleanOrigin());
}
void visitCatchSwitchInst(CatchSwitchInst &I) {
setShadow(&I, getCleanShadow(&I));
setOrigin(&I, getCleanOrigin());
}
void visitFuncletPadInst(FuncletPadInst &I) {
setShadow(&I, getCleanShadow(&I));
setOrigin(&I, getCleanOrigin());
}
void visitGetElementPtrInst(GetElementPtrInst &I) {
handleShadowOr(I);
}
void visitExtractValueInst(ExtractValueInst &I) {
IRBuilder<> IRB(&I);
Value *Agg = I.getAggregateOperand();
LLVM_DEBUG(dbgs() << "ExtractValue: " << I << "\n");
Value *AggShadow = getShadow(Agg);
LLVM_DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n");
Value *ResShadow = IRB.CreateExtractValue(AggShadow, I.getIndices());
LLVM_DEBUG(dbgs() << " ResShadow: " << *ResShadow << "\n");
setShadow(&I, ResShadow);
setOriginForNaryOp(I);
}
void visitInsertValueInst(InsertValueInst &I) {
IRBuilder<> IRB(&I);
LLVM_DEBUG(dbgs() << "InsertValue: " << I << "\n");
Value *AggShadow = getShadow(I.getAggregateOperand());
Value *InsShadow = getShadow(I.getInsertedValueOperand());
LLVM_DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n");
LLVM_DEBUG(dbgs() << " InsShadow: " << *InsShadow << "\n");
Value *Res = IRB.CreateInsertValue(AggShadow, InsShadow, I.getIndices());
LLVM_DEBUG(dbgs() << " Res: " << *Res << "\n");
setShadow(&I, Res);
setOriginForNaryOp(I);
}
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) {
LLVM_DEBUG(dbgs() << "Resume: " << I << "\n");
// Nothing to do here.
}
void visitCleanupReturnInst(CleanupReturnInst &CRI) {
LLVM_DEBUG(dbgs() << "CleanupReturn: " << CRI << "\n");
// Nothing to do here.
}
void visitCatchReturnInst(CatchReturnInst &CRI) {
LLVM_DEBUG(dbgs() << "CatchReturn: " << CRI << "\n");
// Nothing to do here.
}
void instrumentAsmArgument(Value *Operand, Instruction &I, IRBuilder<> &IRB,
const DataLayout &DL, bool isOutput) {
// For each assembly argument, we check its value for being initialized.
// If the argument is a pointer, we assume it points to a single element
// of the corresponding type (or to a 8-byte word, if the type is unsized).
// Each such pointer is instrumented with a call to the runtime library.
Type *OpType = Operand->getType();
// Check the operand value itself.
insertShadowCheck(Operand, &I);
if (!OpType->isPointerTy() || !isOutput) {
assert(!isOutput);
return;
}
Type *ElType = OpType->getPointerElementType();
if (!ElType->isSized())
return;
int Size = DL.getTypeStoreSize(ElType);
Value *Ptr = IRB.CreatePointerCast(Operand, IRB.getInt8PtrTy());
Value *SizeVal = ConstantInt::get(MS.IntptrTy, Size);
IRB.CreateCall(MS.MsanInstrumentAsmStoreFn, {Ptr, SizeVal});
}
/// Get the number of output arguments returned by pointers.
int getNumOutputArgs(InlineAsm *IA, CallBase *CB) {
int NumRetOutputs = 0;
int NumOutputs = 0;
Type *RetTy = cast<Value>(CB)->getType();
if (!RetTy->isVoidTy()) {
// Register outputs are returned via the CallInst return value.
auto *ST = dyn_cast<StructType>(RetTy);
if (ST)
NumRetOutputs = ST->getNumElements();
else
NumRetOutputs = 1;
}
InlineAsm::ConstraintInfoVector Constraints = IA->ParseConstraints();
for (size_t i = 0, n = Constraints.size(); i < n; i++) {
InlineAsm::ConstraintInfo Info = Constraints[i];
switch (Info.Type) {
case InlineAsm::isOutput:
NumOutputs++;
break;
default:
break;
}
}
return NumOutputs - NumRetOutputs;
}
void visitAsmInstruction(Instruction &I) {
// Conservative inline assembly handling: check for poisoned shadow of
// asm() arguments, then unpoison the result and all the memory locations
// pointed to by those arguments.
// An inline asm() statement in C++ contains lists of input and output
// arguments used by the assembly code. These are mapped to operands of the
// CallInst as follows:
// - nR register outputs ("=r) are returned by value in a single structure
// (SSA value of the CallInst);
// - nO other outputs ("=m" and others) are returned by pointer as first
// nO operands of the CallInst;
// - nI inputs ("r", "m" and others) are passed to CallInst as the
// remaining nI operands.
// The total number of asm() arguments in the source is nR+nO+nI, and the
// corresponding CallInst has nO+nI+1 operands (the last operand is the
// function to be called).
const DataLayout &DL = F.getParent()->getDataLayout();
CallBase *CB = cast<CallBase>(&I);
IRBuilder<> IRB(&I);
InlineAsm *IA = cast<InlineAsm>(CB->getCalledValue());
int OutputArgs = getNumOutputArgs(IA, CB);
// The last operand of a CallInst is the function itself.
int NumOperands = CB->getNumOperands() - 1;
// Check input arguments. Doing so before unpoisoning output arguments, so
// that we won't overwrite uninit values before checking them.
for (int i = OutputArgs; i < NumOperands; i++) {
Value *Operand = CB->getOperand(i);
instrumentAsmArgument(Operand, I, IRB, DL, /*isOutput*/ false);
}
// Unpoison output arguments. This must happen before the actual InlineAsm
// call, so that the shadow for memory published in the asm() statement
// remains valid.
for (int i = 0; i < OutputArgs; i++) {
Value *Operand = CB->getOperand(i);
instrumentAsmArgument(Operand, I, IRB, DL, /*isOutput*/ true);
}
setShadow(&I, getCleanShadow(&I));
setOrigin(&I, getCleanOrigin());
}
void visitInstruction(Instruction &I) {
// Everything else: stop propagating and check for poisoned shadow.
if (ClDumpStrictInstructions)
dumpInst(I);
LLVM_DEBUG(dbgs() << "DEFAULT: " << I << "\n");
for (size_t i = 0, n = I.getNumOperands(); i < n; i++) {
Value *Operand = I.getOperand(i);
if (Operand->getType()->isSized())
insertShadowCheck(Operand, &I);
}
setShadow(&I, getCleanShadow(&I));
setOrigin(&I, getCleanOrigin());
}
};
/// AMD64-specific implementation of VarArgHelper.
struct VarArgAMD64Helper : public VarArgHelper {
// An unfortunate workaround for asymmetric lowering of va_arg stuff.
// See a comment in visitCallBase for more details.
static const unsigned AMD64GpEndOffset = 48; // AMD64 ABI Draft 0.99.6 p3.5.7
static const unsigned AMD64FpEndOffsetSSE = 176;
// If SSE is disabled, fp_offset in va_list is zero.
static const unsigned AMD64FpEndOffsetNoSSE = AMD64GpEndOffset;
unsigned AMD64FpEndOffset;
Function &F;
MemorySanitizer &MS;
MemorySanitizerVisitor &MSV;
Value *VAArgTLSCopy = nullptr;
Value *VAArgTLSOriginCopy = nullptr;
Value *VAArgOverflowSize = nullptr;
SmallVector<CallInst*, 16> VAStartInstrumentationList;
enum ArgKind { AK_GeneralPurpose, AK_FloatingPoint, AK_Memory };
VarArgAMD64Helper(Function &F, MemorySanitizer &MS,
MemorySanitizerVisitor &MSV)
: F(F), MS(MS), MSV(MSV) {
AMD64FpEndOffset = AMD64FpEndOffsetSSE;
for (const auto &Attr : F.getAttributes().getFnAttributes()) {
if (Attr.isStringAttribute() &&
(Attr.getKindAsString() == "target-features")) {
if (Attr.getValueAsString().contains("-sse"))
AMD64FpEndOffset = AMD64FpEndOffsetNoSSE;
break;
}
}
}
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 visitCallBase(CallBase &CB, IRBuilder<> &IRB) override {
unsigned GpOffset = 0;
unsigned FpOffset = AMD64GpEndOffset;
unsigned OverflowOffset = AMD64FpEndOffset;
const DataLayout &DL = F.getParent()->getDataLayout();
for (auto ArgIt = CB.arg_begin(), End = CB.arg_end(); ArgIt != End;
++ArgIt) {
Value *A = *ArgIt;
unsigned ArgNo = CB.getArgOperandNo(ArgIt);
bool IsFixed = ArgNo < CB.getFunctionType()->getNumParams();
bool IsByVal = CB.paramHasAttr(ArgNo, Attribute::ByVal);
if (IsByVal) {
// ByVal arguments always go to the overflow area.
// Fixed arguments passed through the overflow area will be stepped
// over by va_start, so don't count them towards the offset.
if (IsFixed)
continue;
assert(A->getType()->isPointerTy());
Type *RealTy = A->getType()->getPointerElementType();
uint64_t ArgSize = DL.getTypeAllocSize(RealTy);
Value *ShadowBase = getShadowPtrForVAArgument(
RealTy, IRB, OverflowOffset, alignTo(ArgSize, 8));
Value *OriginBase = nullptr;
if (MS.TrackOrigins)
OriginBase = getOriginPtrForVAArgument(RealTy, IRB, OverflowOffset);
OverflowOffset += alignTo(ArgSize, 8);
if (!ShadowBase)
continue;
Value *ShadowPtr, *OriginPtr;
std::tie(ShadowPtr, OriginPtr) =
MSV.getShadowOriginPtr(A, IRB, IRB.getInt8Ty(), kShadowTLSAlignment,
/*isStore*/ false);
IRB.CreateMemCpy(ShadowBase, kShadowTLSAlignment, ShadowPtr,
kShadowTLSAlignment, ArgSize);
if (MS.TrackOrigins)
IRB.CreateMemCpy(OriginBase, kShadowTLSAlignment, OriginPtr,
kShadowTLSAlignment, ArgSize);
} else {
ArgKind AK = classifyArgument(A);
if (AK == AK_GeneralPurpose && GpOffset >= AMD64GpEndOffset)
AK = AK_Memory;
if (AK == AK_FloatingPoint && FpOffset >= AMD64FpEndOffset)
AK = AK_Memory;
Value *ShadowBase, *OriginBase = nullptr;
switch (AK) {
case AK_GeneralPurpose:
ShadowBase =
getShadowPtrForVAArgument(A->getType(), IRB, GpOffset, 8);
if (MS.TrackOrigins)
OriginBase =
getOriginPtrForVAArgument(A->getType(), IRB, GpOffset);
GpOffset += 8;
break;
case AK_FloatingPoint:
ShadowBase =
getShadowPtrForVAArgument(A->getType(), IRB, FpOffset, 16);
if (MS.TrackOrigins)
OriginBase =
getOriginPtrForVAArgument(A->getType(), IRB, FpOffset);
FpOffset += 16;
break;
case AK_Memory:
if (IsFixed)
continue;
uint64_t ArgSize = DL.getTypeAllocSize(A->getType());
ShadowBase =
getShadowPtrForVAArgument(A->getType(), IRB, OverflowOffset, 8);
if (MS.TrackOrigins)
OriginBase =
getOriginPtrForVAArgument(A->getType(), IRB, OverflowOffset);
OverflowOffset += alignTo(ArgSize, 8);
}
// Take fixed arguments into account for GpOffset and FpOffset,
// but don't actually store shadows for them.
// TODO(glider): don't call get*PtrForVAArgument() for them.
if (IsFixed)
continue;
if (!ShadowBase)
continue;
Value *Shadow = MSV.getShadow(A);
IRB.CreateAlignedStore(Shadow, ShadowBase, kShadowTLSAlignment);
if (MS.TrackOrigins) {
Value *Origin = MSV.getOrigin(A);
unsigned StoreSize = DL.getTypeStoreSize(Shadow->getType());
MSV.paintOrigin(IRB, Origin, OriginBase, StoreSize,
std::max(kShadowTLSAlignment, kMinOriginAlignment));
}
}
}
Constant *OverflowSize =
ConstantInt::get(IRB.getInt64Ty(), OverflowOffset - AMD64FpEndOffset);
IRB.CreateStore(OverflowSize, MS.VAArgOverflowSizeTLS);
}
/// Compute the shadow address for a given va_arg.
Value *getShadowPtrForVAArgument(Type *Ty, IRBuilder<> &IRB,
unsigned ArgOffset, unsigned ArgSize) {
// Make sure we don't overflow __msan_va_arg_tls.
if (ArgOffset + ArgSize > kParamTLSSize)
return nullptr;
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(Ty), 0),
"_msarg_va_s");
}
/// Compute the origin address for a given va_arg.
Value *getOriginPtrForVAArgument(Type *Ty, IRBuilder<> &IRB, int ArgOffset) {
Value *Base = IRB.CreatePointerCast(MS.VAArgOriginTLS, MS.IntptrTy);
// getOriginPtrForVAArgument() is always called after
// getShadowPtrForVAArgument(), so __msan_va_arg_origin_tls can never
// overflow.
Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
return IRB.CreateIntToPtr(Base, PointerType::get(MS.OriginTy, 0),
"_msarg_va_o");
}
void unpoisonVAListTagForInst(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Value *VAListTag = I.getArgOperand(0);
Value *ShadowPtr, *OriginPtr;
const Align Alignment = Align(8);
std::tie(ShadowPtr, OriginPtr) =
MSV.getShadowOriginPtr(VAListTag, IRB, IRB.getInt8Ty(), Alignment,
/*isStore*/ true);
// Unpoison the whole __va_list_tag.
// FIXME: magic ABI constants.
IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
/* size */ 24, Alignment, false);
// We shouldn't need to zero out the origins, as they're only checked for
// nonzero shadow.
}
void visitVAStartInst(VAStartInst &I) override {
if (F.getCallingConv() == CallingConv::Win64)
return;
VAStartInstrumentationList.push_back(&I);
unpoisonVAListTagForInst(I);
}
void visitVACopyInst(VACopyInst &I) override {
if (F.getCallingConv() == CallingConv::Win64) return;
unpoisonVAListTagForInst(I);
}
void finalizeInstrumentation() override {
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(MSV.ActualFnStart->getFirstNonPHI());
VAArgOverflowSize =
IRB.CreateLoad(IRB.getInt64Ty(), MS.VAArgOverflowSizeTLS);
Value *CopySize =
IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, AMD64FpEndOffset),
VAArgOverflowSize);
VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
IRB.CreateMemCpy(VAArgTLSCopy, Align(8), MS.VAArgTLS, Align(8), CopySize);
if (MS.TrackOrigins) {
VAArgTLSOriginCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
IRB.CreateMemCpy(VAArgTLSOriginCopy, Align(8), MS.VAArgOriginTLS,
Align(8), CopySize);
}
}
// 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);
Type *RegSaveAreaPtrTy = Type::getInt64PtrTy(*MS.C);
Value *RegSaveAreaPtrPtr = IRB.CreateIntToPtr(
IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
ConstantInt::get(MS.IntptrTy, 16)),
PointerType::get(RegSaveAreaPtrTy, 0));
Value *RegSaveAreaPtr =
IRB.CreateLoad(RegSaveAreaPtrTy, RegSaveAreaPtrPtr);
Value *RegSaveAreaShadowPtr, *RegSaveAreaOriginPtr;
const Align Alignment = Align(16);
std::tie(RegSaveAreaShadowPtr, RegSaveAreaOriginPtr) =
MSV.getShadowOriginPtr(RegSaveAreaPtr, IRB, IRB.getInt8Ty(),
Alignment, /*isStore*/ true);
IRB.CreateMemCpy(RegSaveAreaShadowPtr, Alignment, VAArgTLSCopy, Alignment,
AMD64FpEndOffset);
if (MS.TrackOrigins)
IRB.CreateMemCpy(RegSaveAreaOriginPtr, Alignment, VAArgTLSOriginCopy,
Alignment, AMD64FpEndOffset);
Type *OverflowArgAreaPtrTy = Type::getInt64PtrTy(*MS.C);
Value *OverflowArgAreaPtrPtr = IRB.CreateIntToPtr(
IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
ConstantInt::get(MS.IntptrTy, 8)),
PointerType::get(OverflowArgAreaPtrTy, 0));
Value *OverflowArgAreaPtr =
IRB.CreateLoad(OverflowArgAreaPtrTy, OverflowArgAreaPtrPtr);
Value *OverflowArgAreaShadowPtr, *OverflowArgAreaOriginPtr;
std::tie(OverflowArgAreaShadowPtr, OverflowArgAreaOriginPtr) =
MSV.getShadowOriginPtr(OverflowArgAreaPtr, IRB, IRB.getInt8Ty(),
Alignment, /*isStore*/ true);
Value *SrcPtr = IRB.CreateConstGEP1_32(IRB.getInt8Ty(), VAArgTLSCopy,
AMD64FpEndOffset);
IRB.CreateMemCpy(OverflowArgAreaShadowPtr, Alignment, SrcPtr, Alignment,
VAArgOverflowSize);
if (MS.TrackOrigins) {
SrcPtr = IRB.CreateConstGEP1_32(IRB.getInt8Ty(), VAArgTLSOriginCopy,
AMD64FpEndOffset);
IRB.CreateMemCpy(OverflowArgAreaOriginPtr, Alignment, SrcPtr, Alignment,
VAArgOverflowSize);
}
}
}
};
/// MIPS64-specific implementation of VarArgHelper.
struct VarArgMIPS64Helper : public VarArgHelper {
Function &F;
MemorySanitizer &MS;
MemorySanitizerVisitor &MSV;
Value *VAArgTLSCopy = nullptr;
Value *VAArgSize = nullptr;
SmallVector<CallInst*, 16> VAStartInstrumentationList;
VarArgMIPS64Helper(Function &F, MemorySanitizer &MS,
MemorySanitizerVisitor &MSV) : F(F), MS(MS), MSV(MSV) {}
void visitCallBase(CallBase &CB, IRBuilder<> &IRB) override {
unsigned VAArgOffset = 0;
const DataLayout &DL = F.getParent()->getDataLayout();
for (auto ArgIt = CB.arg_begin() + CB.getFunctionType()->getNumParams(),
End = CB.arg_end();
ArgIt != End; ++ArgIt) {
Triple TargetTriple(F.getParent()->getTargetTriple());
Value *A = *ArgIt;
Value *Base;
uint64_t ArgSize = DL.getTypeAllocSize(A->getType());
if (TargetTriple.getArch() == Triple::mips64) {
// Adjusting the shadow for argument with size < 8 to match the placement
// of bits in big endian system
if (ArgSize < 8)
VAArgOffset += (8 - ArgSize);
}
Base = getShadowPtrForVAArgument(A->getType(), IRB, VAArgOffset, ArgSize);
VAArgOffset += ArgSize;
VAArgOffset = alignTo(VAArgOffset, 8);
if (!Base)
continue;
IRB.CreateAlignedStore(MSV.getShadow(A), Base, kShadowTLSAlignment);
}
Constant *TotalVAArgSize = ConstantInt::get(IRB.getInt64Ty(), VAArgOffset);
// Here using VAArgOverflowSizeTLS as VAArgSizeTLS to avoid creation of
// a new class member i.e. it is the total size of all VarArgs.
IRB.CreateStore(TotalVAArgSize, MS.VAArgOverflowSizeTLS);
}
/// Compute the shadow address for a given va_arg.
Value *getShadowPtrForVAArgument(Type *Ty, IRBuilder<> &IRB,
unsigned ArgOffset, unsigned ArgSize) {
// Make sure we don't overflow __msan_va_arg_tls.
if (ArgOffset + ArgSize > kParamTLSSize)
return nullptr;
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(Ty), 0),
"_msarg");
}
void visitVAStartInst(VAStartInst &I) override {
IRBuilder<> IRB(&I);
VAStartInstrumentationList.push_back(&I);
Value *VAListTag = I.getArgOperand(0);
Value *ShadowPtr, *OriginPtr;
const Align Alignment = Align(8);
std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
/* size */ 8, Alignment, false);
}
void visitVACopyInst(VACopyInst &I) override {
IRBuilder<> IRB(&I);
VAStartInstrumentationList.push_back(&I);
Value *VAListTag = I.getArgOperand(0);
Value *ShadowPtr, *OriginPtr;
const Align Alignment = Align(8);
std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
/* size */ 8, Alignment, false);
}
void finalizeInstrumentation() override {
assert(!VAArgSize && !VAArgTLSCopy &&
"finalizeInstrumentation called twice");
IRBuilder<> IRB(MSV.ActualFnStart->getFirstNonPHI());
VAArgSize = IRB.CreateLoad(IRB.getInt64Ty(), MS.VAArgOverflowSizeTLS);
Value *CopySize = IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, 0),
VAArgSize);
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.
VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
IRB.CreateMemCpy(VAArgTLSCopy, Align(8), MS.VAArgTLS, Align(8), CopySize);
}
// 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);
Type *RegSaveAreaPtrTy = Type::getInt64PtrTy(*MS.C);
Value *RegSaveAreaPtrPtr =
IRB.CreateIntToPtr(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
PointerType::get(RegSaveAreaPtrTy, 0));
Value *RegSaveAreaPtr =
IRB.CreateLoad(RegSaveAreaPtrTy, RegSaveAreaPtrPtr);
Value *RegSaveAreaShadowPtr, *RegSaveAreaOriginPtr;
const Align Alignment = Align(8);
std::tie(RegSaveAreaShadowPtr, RegSaveAreaOriginPtr) =
MSV.getShadowOriginPtr(RegSaveAreaPtr, IRB, IRB.getInt8Ty(),
Alignment, /*isStore*/ true);
IRB.CreateMemCpy(RegSaveAreaShadowPtr, Alignment, VAArgTLSCopy, Alignment,
CopySize);
}
}
};
/// AArch64-specific implementation of VarArgHelper.
struct VarArgAArch64Helper : public VarArgHelper {
static const unsigned kAArch64GrArgSize = 64;
static const unsigned kAArch64VrArgSize = 128;
static const unsigned AArch64GrBegOffset = 0;
static const unsigned AArch64GrEndOffset = kAArch64GrArgSize;
// Make VR space aligned to 16 bytes.
static const unsigned AArch64VrBegOffset = AArch64GrEndOffset;
static const unsigned AArch64VrEndOffset = AArch64VrBegOffset
+ kAArch64VrArgSize;
static const unsigned AArch64VAEndOffset = AArch64VrEndOffset;
Function &F;
MemorySanitizer &MS;
MemorySanitizerVisitor &MSV;
Value *VAArgTLSCopy = nullptr;
Value *VAArgOverflowSize = nullptr;
SmallVector<CallInst*, 16> VAStartInstrumentationList;
enum ArgKind { AK_GeneralPurpose, AK_FloatingPoint, AK_Memory };
VarArgAArch64Helper(Function &F, MemorySanitizer &MS,
MemorySanitizerVisitor &MSV) : F(F), MS(MS), MSV(MSV) {}
ArgKind classifyArgument(Value* arg) {
Type *T = arg->getType();
if (T->isFPOrFPVectorTy())
return AK_FloatingPoint;
if ((T->isIntegerTy() && T->getPrimitiveSizeInBits() <= 64)
|| (T->isPointerTy()))
return AK_GeneralPurpose;
return AK_Memory;
}
// The instrumentation stores the argument shadow in a non ABI-specific
// format because it does not know which argument is named (since Clang,
// like x86_64 case, lowers the va_args in the frontend and this pass only
// sees the low level code that deals with va_list internals).
// The first seven GR registers are saved in the first 56 bytes of the
// va_arg tls arra, followers by the first 8 FP/SIMD registers, and then
// the remaining arguments.
// Using constant offset within the va_arg TLS array allows fast copy
// in the finalize instrumentation.
void visitCallBase(CallBase &CB, IRBuilder<> &IRB) override {
unsigned GrOffset = AArch64GrBegOffset;
unsigned VrOffset = AArch64VrBegOffset;
unsigned OverflowOffset = AArch64VAEndOffset;
const DataLayout &DL = F.getParent()->getDataLayout();
for (auto ArgIt = CB.arg_begin(), End = CB.arg_end(); ArgIt != End;
++ArgIt) {
Value *A = *ArgIt;
unsigned ArgNo = CB.getArgOperandNo(ArgIt);
bool IsFixed = ArgNo < CB.getFunctionType()->getNumParams();
ArgKind AK = classifyArgument(A);
if (AK == AK_GeneralPurpose && GrOffset >= AArch64GrEndOffset)
AK = AK_Memory;
if (AK == AK_FloatingPoint && VrOffset >= AArch64VrEndOffset)
AK = AK_Memory;
Value *Base;
switch (AK) {
case AK_GeneralPurpose:
Base = getShadowPtrForVAArgument(A->getType(), IRB, GrOffset, 8);
GrOffset += 8;
break;
case AK_FloatingPoint:
Base = getShadowPtrForVAArgument(A->getType(), IRB, VrOffset, 8);
VrOffset += 16;
break;
case AK_Memory:
// Don't count fixed arguments in the overflow area - va_start will
// skip right over them.
if (IsFixed)
continue;
uint64_t ArgSize = DL.getTypeAllocSize(A->getType());
Base = getShadowPtrForVAArgument(A->getType(), IRB, OverflowOffset,
alignTo(ArgSize, 8));
OverflowOffset += alignTo(ArgSize, 8);
break;
}
// Count Gp/Vr fixed arguments to their respective offsets, but don't
// bother to actually store a shadow.
if (IsFixed)
continue;
if (!Base)
continue;
IRB.CreateAlignedStore(MSV.getShadow(A), Base, kShadowTLSAlignment);
}
Constant *OverflowSize =
ConstantInt::get(IRB.getInt64Ty(), OverflowOffset - AArch64VAEndOffset);
IRB.CreateStore(OverflowSize, MS.VAArgOverflowSizeTLS);
}
/// Compute the shadow address for a given va_arg.
Value *getShadowPtrForVAArgument(Type *Ty, IRBuilder<> &IRB,
unsigned ArgOffset, unsigned ArgSize) {
// Make sure we don't overflow __msan_va_arg_tls.
if (ArgOffset + ArgSize > kParamTLSSize)
return nullptr;
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(Ty), 0),
"_msarg");
}
void visitVAStartInst(VAStartInst &I) override {
IRBuilder<> IRB(&I);
VAStartInstrumentationList.push_back(&I);
Value *VAListTag = I.getArgOperand(0);
Value *ShadowPtr, *OriginPtr;
const Align Alignment = Align(8);
std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
/* size */ 32, Alignment, false);
}
void visitVACopyInst(VACopyInst &I) override {
IRBuilder<> IRB(&I);
VAStartInstrumentationList.push_back(&I);
Value *VAListTag = I.getArgOperand(0);
Value *ShadowPtr, *OriginPtr;
const Align Alignment = Align(8);
std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
/* size */ 32, Alignment, false);
}
// Retrieve a va_list field of 'void*' size.
Value* getVAField64(IRBuilder<> &IRB, Value *VAListTag, int offset) {
Value *SaveAreaPtrPtr =
IRB.CreateIntToPtr(
IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
ConstantInt::get(MS.IntptrTy, offset)),
Type::getInt64PtrTy(*MS.C));
return IRB.CreateLoad(Type::getInt64Ty(*MS.C), SaveAreaPtrPtr);
}
// Retrieve a va_list field of 'int' size.
Value* getVAField32(IRBuilder<> &IRB, Value *VAListTag, int offset) {
Value *SaveAreaPtr =
IRB.CreateIntToPtr(
IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
ConstantInt::get(MS.IntptrTy, offset)),
Type::getInt32PtrTy(*MS.C));
Value *SaveArea32 = IRB.CreateLoad(IRB.getInt32Ty(), SaveAreaPtr);
return IRB.CreateSExt(SaveArea32, MS.IntptrTy);
}
void finalizeInstrumentation() override {
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(MSV.ActualFnStart->getFirstNonPHI());
VAArgOverflowSize =
IRB.CreateLoad(IRB.getInt64Ty(), MS.VAArgOverflowSizeTLS);
Value *CopySize =
IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, AArch64VAEndOffset),
VAArgOverflowSize);
VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
IRB.CreateMemCpy(VAArgTLSCopy, Align(8), MS.VAArgTLS, Align(8), CopySize);
}
Value *GrArgSize = ConstantInt::get(MS.IntptrTy, kAArch64GrArgSize);
Value *VrArgSize = ConstantInt::get(MS.IntptrTy, kAArch64VrArgSize);
// 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);
// The variadic ABI for AArch64 creates two areas to save the incoming
// argument registers (one for 64-bit general register xn-x7 and another
// for 128-bit FP/SIMD vn-v7).
// We need then to propagate the shadow arguments on both regions
// 'va::__gr_top + va::__gr_offs' and 'va::__vr_top + va::__vr_offs'.
// The remaining arguments are saved on shadow for 'va::stack'.
// One caveat is it requires only to propagate the non-named arguments,
// however on the call site instrumentation 'all' the arguments are
// saved. So to copy the shadow values from the va_arg TLS array
// we need to adjust the offset for both GR and VR fields based on
// the __{gr,vr}_offs value (since they are stores based on incoming
// named arguments).
// Read the stack pointer from the va_list.
Value *StackSaveAreaPtr = getVAField64(IRB, VAListTag, 0);
// Read both the __gr_top and __gr_off and add them up.
Value *GrTopSaveAreaPtr = getVAField64(IRB, VAListTag, 8);
Value *GrOffSaveArea = getVAField32(IRB, VAListTag, 24);
Value *GrRegSaveAreaPtr = IRB.CreateAdd(GrTopSaveAreaPtr, GrOffSaveArea);
// Read both the __vr_top and __vr_off and add them up.
Value *VrTopSaveAreaPtr = getVAField64(IRB, VAListTag, 16);
Value *VrOffSaveArea = getVAField32(IRB, VAListTag, 28);
Value *VrRegSaveAreaPtr = IRB.CreateAdd(VrTopSaveAreaPtr, VrOffSaveArea);
// It does not know how many named arguments is being used and, on the
// callsite all the arguments were saved. Since __gr_off is defined as
// '0 - ((8 - named_gr) * 8)', the idea is to just propagate the variadic
// argument by ignoring the bytes of shadow from named arguments.
Value *GrRegSaveAreaShadowPtrOff =
IRB.CreateAdd(GrArgSize, GrOffSaveArea);
Value *GrRegSaveAreaShadowPtr =
MSV.getShadowOriginPtr(GrRegSaveAreaPtr, IRB, IRB.getInt8Ty(),
Align(8), /*isStore*/ true)
.first;
Value *GrSrcPtr = IRB.CreateInBoundsGEP(IRB.getInt8Ty(), VAArgTLSCopy,
GrRegSaveAreaShadowPtrOff);
Value *GrCopySize = IRB.CreateSub(GrArgSize, GrRegSaveAreaShadowPtrOff);
IRB.CreateMemCpy(GrRegSaveAreaShadowPtr, Align(8), GrSrcPtr, Align(8),
GrCopySize);
// Again, but for FP/SIMD values.
Value *VrRegSaveAreaShadowPtrOff =
IRB.CreateAdd(VrArgSize, VrOffSaveArea);
Value *VrRegSaveAreaShadowPtr =
MSV.getShadowOriginPtr(VrRegSaveAreaPtr, IRB, IRB.getInt8Ty(),
Align(8), /*isStore*/ true)
.first;
Value *VrSrcPtr = IRB.CreateInBoundsGEP(
IRB.getInt8Ty(),
IRB.CreateInBoundsGEP(IRB.getInt8Ty(), VAArgTLSCopy,
IRB.getInt32(AArch64VrBegOffset)),
VrRegSaveAreaShadowPtrOff);
Value *VrCopySize = IRB.CreateSub(VrArgSize, VrRegSaveAreaShadowPtrOff);
IRB.CreateMemCpy(VrRegSaveAreaShadowPtr, Align(8), VrSrcPtr, Align(8),
VrCopySize);
// And finally for remaining arguments.
Value *StackSaveAreaShadowPtr =
MSV.getShadowOriginPtr(StackSaveAreaPtr, IRB, IRB.getInt8Ty(),
Align(16), /*isStore*/ true)
.first;
Value *StackSrcPtr =
IRB.CreateInBoundsGEP(IRB.getInt8Ty(), VAArgTLSCopy,
IRB.getInt32(AArch64VAEndOffset));
IRB.CreateMemCpy(StackSaveAreaShadowPtr, Align(16), StackSrcPtr,
Align(16), VAArgOverflowSize);
}
}
};
/// PowerPC64-specific implementation of VarArgHelper.
struct VarArgPowerPC64Helper : public VarArgHelper {
Function &F;
MemorySanitizer &MS;
MemorySanitizerVisitor &MSV;
Value *VAArgTLSCopy = nullptr;
Value *VAArgSize = nullptr;
SmallVector<CallInst*, 16> VAStartInstrumentationList;
VarArgPowerPC64Helper(Function &F, MemorySanitizer &MS,
MemorySanitizerVisitor &MSV) : F(F), MS(MS), MSV(MSV) {}
void visitCallBase(CallBase &CB, IRBuilder<> &IRB) override {
// For PowerPC, we need to deal with alignment of stack arguments -
// they are mostly aligned to 8 bytes, but vectors and i128 arrays
// are aligned to 16 bytes, byvals can be aligned to 8 or 16 bytes,
// and QPX vectors are aligned to 32 bytes. For that reason, we
// compute current offset from stack pointer (which is always properly
// aligned), and offset for the first vararg, then subtract them.
unsigned VAArgBase;
Triple TargetTriple(F.getParent()->getTargetTriple());
// Parameter save area starts at 48 bytes from frame pointer for ABIv1,
// and 32 bytes for ABIv2. This is usually determined by target
// endianness, but in theory could be overridden by function attribute.
// For simplicity, we ignore it here (it'd only matter for QPX vectors).
if (TargetTriple.getArch() == Triple::ppc64)
VAArgBase = 48;
else
VAArgBase = 32;
unsigned VAArgOffset = VAArgBase;
const DataLayout &DL = F.getParent()->getDataLayout();
for (auto ArgIt = CB.arg_begin(), End = CB.arg_end(); ArgIt != End;
++ArgIt) {
Value *A = *ArgIt;
unsigned ArgNo = CB.getArgOperandNo(ArgIt);
bool IsFixed = ArgNo < CB.getFunctionType()->getNumParams();
bool IsByVal = CB.paramHasAttr(ArgNo, Attribute::ByVal);
if (IsByVal) {
assert(A->getType()->isPointerTy());
Type *RealTy = A->getType()->getPointerElementType();
uint64_t ArgSize = DL.getTypeAllocSize(RealTy);
MaybeAlign ArgAlign = CB.getParamAlign(ArgNo);
if (!ArgAlign || *ArgAlign < Align(8))
ArgAlign = Align(8);
VAArgOffset = alignTo(VAArgOffset, ArgAlign);
if (!IsFixed) {
Value *Base = getShadowPtrForVAArgument(
RealTy, IRB, VAArgOffset - VAArgBase, ArgSize);
if (Base) {
Value *AShadowPtr, *AOriginPtr;
std::tie(AShadowPtr, AOriginPtr) =
MSV.getShadowOriginPtr(A, IRB, IRB.getInt8Ty(),
kShadowTLSAlignment, /*isStore*/ false);
IRB.CreateMemCpy(Base, kShadowTLSAlignment, AShadowPtr,
kShadowTLSAlignment, ArgSize);
}
}
VAArgOffset += alignTo(ArgSize, 8);
} else {
Value *Base;
uint64_t ArgSize = DL.getTypeAllocSize(A->getType());
uint64_t ArgAlign = 8;
if (A->getType()->isArrayTy()) {
// Arrays are aligned to element size, except for long double
// arrays, which are aligned to 8 bytes.
Type *ElementTy = A->getType()->getArrayElementType();
if (!ElementTy->isPPC_FP128Ty())
ArgAlign = DL.getTypeAllocSize(ElementTy);
} else if (A->getType()->isVectorTy()) {
// Vectors are naturally aligned.
ArgAlign = DL.getTypeAllocSize(A->getType());
}
if (ArgAlign < 8)
ArgAlign = 8;
VAArgOffset = alignTo(VAArgOffset, ArgAlign);
if (DL.isBigEndian()) {
// Adjusting the shadow for argument with size < 8 to match the placement
// of bits in big endian system
if (ArgSize < 8)
VAArgOffset += (8 - ArgSize);
}
if (!IsFixed) {
Base = getShadowPtrForVAArgument(A->getType(), IRB,
VAArgOffset - VAArgBase, ArgSize);
if (Base)
IRB.CreateAlignedStore(MSV.getShadow(A), Base, kShadowTLSAlignment);
}
VAArgOffset += ArgSize;
VAArgOffset = alignTo(VAArgOffset, 8);
}
if (IsFixed)
VAArgBase = VAArgOffset;
}
Constant *TotalVAArgSize = ConstantInt::get(IRB.getInt64Ty(),
VAArgOffset - VAArgBase);
// Here using VAArgOverflowSizeTLS as VAArgSizeTLS to avoid creation of
// a new class member i.e. it is the total size of all VarArgs.
IRB.CreateStore(TotalVAArgSize, MS.VAArgOverflowSizeTLS);
}
/// Compute the shadow address for a given va_arg.
Value *getShadowPtrForVAArgument(Type *Ty, IRBuilder<> &IRB,
unsigned ArgOffset, unsigned ArgSize) {
// Make sure we don't overflow __msan_va_arg_tls.
if (ArgOffset + ArgSize > kParamTLSSize)
return nullptr;
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(Ty), 0),
"_msarg");
}
void visitVAStartInst(VAStartInst &I) override {
IRBuilder<> IRB(&I);
VAStartInstrumentationList.push_back(&I);
Value *VAListTag = I.getArgOperand(0);
Value *ShadowPtr, *OriginPtr;
const Align Alignment = Align(8);
std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
/* size */ 8, Alignment, false);
}
void visitVACopyInst(VACopyInst &I) override {
IRBuilder<> IRB(&I);
Value *VAListTag = I.getArgOperand(0);
Value *ShadowPtr, *OriginPtr;
const Align Alignment = Align(8);
std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
// Unpoison the whole __va_list_tag.
// FIXME: magic ABI constants.
IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
/* size */ 8, Alignment, false);
}
void finalizeInstrumentation() override {
assert(!VAArgSize && !VAArgTLSCopy &&
"finalizeInstrumentation called twice");
IRBuilder<> IRB(MSV.ActualFnStart->getFirstNonPHI());
VAArgSize = IRB.CreateLoad(IRB.getInt64Ty(), MS.VAArgOverflowSizeTLS);
Value *CopySize = IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, 0),
VAArgSize);
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.
VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
IRB.CreateMemCpy(VAArgTLSCopy, Align(8), MS.VAArgTLS, Align(8), CopySize);
}
// 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);
Type *RegSaveAreaPtrTy = Type::getInt64PtrTy(*MS.C);
Value *RegSaveAreaPtrPtr =
IRB.CreateIntToPtr(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
PointerType::get(RegSaveAreaPtrTy, 0));
Value *RegSaveAreaPtr =
IRB.CreateLoad(RegSaveAreaPtrTy, RegSaveAreaPtrPtr);
Value *RegSaveAreaShadowPtr, *RegSaveAreaOriginPtr;
const Align Alignment = Align(8);
std::tie(RegSaveAreaShadowPtr, RegSaveAreaOriginPtr) =
MSV.getShadowOriginPtr(RegSaveAreaPtr, IRB, IRB.getInt8Ty(),
Alignment, /*isStore*/ true);
IRB.CreateMemCpy(RegSaveAreaShadowPtr, Alignment, VAArgTLSCopy, Alignment,
CopySize);
}
}
};
/// SystemZ-specific implementation of VarArgHelper.
struct VarArgSystemZHelper : public VarArgHelper {
static const unsigned SystemZGpOffset = 16;
static const unsigned SystemZGpEndOffset = 56;
static const unsigned SystemZFpOffset = 128;
static const unsigned SystemZFpEndOffset = 160;
static const unsigned SystemZMaxVrArgs = 8;
static const unsigned SystemZRegSaveAreaSize = 160;
static const unsigned SystemZOverflowOffset = 160;
static const unsigned SystemZVAListTagSize = 32;
static const unsigned SystemZOverflowArgAreaPtrOffset = 16;
static const unsigned SystemZRegSaveAreaPtrOffset = 24;
Function &F;
MemorySanitizer &MS;
MemorySanitizerVisitor &MSV;
Value *VAArgTLSCopy = nullptr;
Value *VAArgTLSOriginCopy = nullptr;
Value *VAArgOverflowSize = nullptr;
SmallVector<CallInst *, 16> VAStartInstrumentationList;
enum class ArgKind {
GeneralPurpose,
FloatingPoint,
Vector,
Memory,
Indirect,
};
enum class ShadowExtension { None, Zero, Sign };
VarArgSystemZHelper(Function &F, MemorySanitizer &MS,
MemorySanitizerVisitor &MSV)
: F(F), MS(MS), MSV(MSV) {}
ArgKind classifyArgument(Type *T, bool IsSoftFloatABI) {
// T is a SystemZABIInfo::classifyArgumentType() output, and there are
// only a few possibilities of what it can be. In particular, enums, single
// element structs and large types have already been taken care of.
// Some i128 and fp128 arguments are converted to pointers only in the
// back end.
if (T->isIntegerTy(128) || T->isFP128Ty())
return ArgKind::Indirect;
if (T->isFloatingPointTy())
return IsSoftFloatABI ? ArgKind::GeneralPurpose : ArgKind::FloatingPoint;
if (T->isIntegerTy() || T->isPointerTy())
return ArgKind::GeneralPurpose;
if (T->isVectorTy())
return ArgKind::Vector;
return ArgKind::Memory;
}
ShadowExtension getShadowExtension(const CallBase &CB, unsigned ArgNo) {
// ABI says: "One of the simple integer types no more than 64 bits wide.
// ... If such an argument is shorter than 64 bits, replace it by a full
// 64-bit integer representing the same number, using sign or zero
// extension". Shadow for an integer argument has the same type as the
// argument itself, so it can be sign or zero extended as well.
bool ZExt = CB.paramHasAttr(ArgNo, Attribute::ZExt);
bool SExt = CB.paramHasAttr(ArgNo, Attribute::SExt);
if (ZExt) {
assert(!SExt);
return ShadowExtension::Zero;
}
if (SExt) {
assert(!ZExt);
return ShadowExtension::Sign;
}
return ShadowExtension::None;
}
void visitCallBase(CallBase &CB, IRBuilder<> &IRB) override {
bool IsSoftFloatABI = CB.getCalledFunction()
->getFnAttribute("use-soft-float")
.getValueAsString() == "true";
unsigned GpOffset = SystemZGpOffset;
unsigned FpOffset = SystemZFpOffset;
unsigned VrIndex = 0;
unsigned OverflowOffset = SystemZOverflowOffset;
const DataLayout &DL = F.getParent()->getDataLayout();
for (auto ArgIt = CB.arg_begin(), End = CB.arg_end(); ArgIt != End;
++ArgIt) {
Value *A = *ArgIt;
unsigned ArgNo = CB.getArgOperandNo(ArgIt);
bool IsFixed = ArgNo < CB.getFunctionType()->getNumParams();
// SystemZABIInfo does not produce ByVal parameters.
assert(!CB.paramHasAttr(ArgNo, Attribute::ByVal));
Type *T = A->getType();
ArgKind AK = classifyArgument(T, IsSoftFloatABI);
if (AK == ArgKind::Indirect) {
T = PointerType::get(T, 0);
AK = ArgKind::GeneralPurpose;
}
if (AK == ArgKind::GeneralPurpose && GpOffset >= SystemZGpEndOffset)
AK = ArgKind::Memory;
if (AK == ArgKind::FloatingPoint && FpOffset >= SystemZFpEndOffset)
AK = ArgKind::Memory;
if (AK == ArgKind::Vector && (VrIndex >= SystemZMaxVrArgs || !IsFixed))
AK = ArgKind::Memory;
Value *ShadowBase = nullptr;
Value *OriginBase = nullptr;
ShadowExtension SE = ShadowExtension::None;
switch (AK) {
case ArgKind::GeneralPurpose: {
// Always keep track of GpOffset, but store shadow only for varargs.
uint64_t ArgSize = 8;
if (GpOffset + ArgSize <= kParamTLSSize) {
if (!IsFixed) {
SE = getShadowExtension(CB, ArgNo);
uint64_t GapSize = 0;
if (SE == ShadowExtension::None) {
uint64_t ArgAllocSize = DL.getTypeAllocSize(T);
assert(ArgAllocSize <= ArgSize);
GapSize = ArgSize - ArgAllocSize;
}
ShadowBase = getShadowAddrForVAArgument(IRB, GpOffset + GapSize);
if (MS.TrackOrigins)
OriginBase = getOriginPtrForVAArgument(IRB, GpOffset + GapSize);
}
GpOffset += ArgSize;
} else {
GpOffset = kParamTLSSize;
}
break;
}
case ArgKind::FloatingPoint: {
// Always keep track of FpOffset, but store shadow only for varargs.
uint64_t ArgSize = 8;
if (FpOffset + ArgSize <= kParamTLSSize) {
if (!IsFixed) {
// PoP says: "A short floating-point datum requires only the
// left-most 32 bit positions of a floating-point register".
// Therefore, in contrast to AK_GeneralPurpose and AK_Memory,
// don't extend shadow and don't mind the gap.
ShadowBase = getShadowAddrForVAArgument(IRB, FpOffset);
if (MS.TrackOrigins)
OriginBase = getOriginPtrForVAArgument(IRB, FpOffset);
}
FpOffset += ArgSize;
} else {
FpOffset = kParamTLSSize;
}
break;
}
case ArgKind::Vector: {
// Keep track of VrIndex. No need to store shadow, since vector varargs
// go through AK_Memory.
assert(IsFixed);
VrIndex++;
break;
}
case ArgKind::Memory: {
// Keep track of OverflowOffset and store shadow only for varargs.
// Ignore fixed args, since we need to copy only the vararg portion of
// the overflow area shadow.
if (!IsFixed) {
uint64_t ArgAllocSize = DL.getTypeAllocSize(T);
uint64_t ArgSize = alignTo(ArgAllocSize, 8);
if (OverflowOffset + ArgSize <= kParamTLSSize) {
SE = getShadowExtension(CB, ArgNo);
uint64_t GapSize =
SE == ShadowExtension::None ? ArgSize - ArgAllocSize : 0;
ShadowBase =
getShadowAddrForVAArgument(IRB, OverflowOffset + GapSize);
if (MS.TrackOrigins)
OriginBase =
getOriginPtrForVAArgument(IRB, OverflowOffset + GapSize);
OverflowOffset += ArgSize;
} else {
OverflowOffset = kParamTLSSize;
}
}
break;
}
case ArgKind::Indirect:
llvm_unreachable("Indirect must be converted to GeneralPurpose");
}
if (ShadowBase == nullptr)
continue;
Value *Shadow = MSV.getShadow(A);
if (SE != ShadowExtension::None)
Shadow = MSV.CreateShadowCast(IRB, Shadow, IRB.getInt64Ty(),
/*Signed*/ SE == ShadowExtension::Sign);
ShadowBase = IRB.CreateIntToPtr(
ShadowBase, PointerType::get(Shadow->getType(), 0), "_msarg_va_s");
IRB.CreateStore(Shadow, ShadowBase);
if (MS.TrackOrigins) {
Value *Origin = MSV.getOrigin(A);
unsigned StoreSize = DL.getTypeStoreSize(Shadow->getType());
MSV.paintOrigin(IRB, Origin, OriginBase, StoreSize,
kMinOriginAlignment);
}
}
Constant *OverflowSize = ConstantInt::get(
IRB.getInt64Ty(), OverflowOffset - SystemZOverflowOffset);
IRB.CreateStore(OverflowSize, MS.VAArgOverflowSizeTLS);
}
Value *getShadowAddrForVAArgument(IRBuilder<> &IRB, unsigned ArgOffset) {
Value *Base = IRB.CreatePointerCast(MS.VAArgTLS, MS.IntptrTy);
return IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
}
Value *getOriginPtrForVAArgument(IRBuilder<> &IRB, int ArgOffset) {
Value *Base = IRB.CreatePointerCast(MS.VAArgOriginTLS, MS.IntptrTy);
Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
return IRB.CreateIntToPtr(Base, PointerType::get(MS.OriginTy, 0),
"_msarg_va_o");
}
void unpoisonVAListTagForInst(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Value *VAListTag = I.getArgOperand(0);
Value *ShadowPtr, *OriginPtr;
const Align Alignment = Align(8);
std::tie(ShadowPtr, OriginPtr) =
MSV.getShadowOriginPtr(VAListTag, IRB, IRB.getInt8Ty(), Alignment,
/*isStore*/ true);
IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
SystemZVAListTagSize, Alignment, false);
}
void visitVAStartInst(VAStartInst &I) override {
VAStartInstrumentationList.push_back(&I);
unpoisonVAListTagForInst(I);
}
void visitVACopyInst(VACopyInst &I) override { unpoisonVAListTagForInst(I); }
void copyRegSaveArea(IRBuilder<> &IRB, Value *VAListTag) {
Type *RegSaveAreaPtrTy = Type::getInt64PtrTy(*MS.C);
Value *RegSaveAreaPtrPtr = IRB.CreateIntToPtr(
IRB.CreateAdd(
IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
ConstantInt::get(MS.IntptrTy, SystemZRegSaveAreaPtrOffset)),
PointerType::get(RegSaveAreaPtrTy, 0));
Value *RegSaveAreaPtr = IRB.CreateLoad(RegSaveAreaPtrTy, RegSaveAreaPtrPtr);
Value *RegSaveAreaShadowPtr, *RegSaveAreaOriginPtr;
const Align Alignment = Align(8);
std::tie(RegSaveAreaShadowPtr, RegSaveAreaOriginPtr) =
MSV.getShadowOriginPtr(RegSaveAreaPtr, IRB, IRB.getInt8Ty(), Alignment,
/*isStore*/ true);
// TODO(iii): copy only fragments filled by visitCallBase()
IRB.CreateMemCpy(RegSaveAreaShadowPtr, Alignment, VAArgTLSCopy, Alignment,
SystemZRegSaveAreaSize);
if (MS.TrackOrigins)
IRB.CreateMemCpy(RegSaveAreaOriginPtr, Alignment, VAArgTLSOriginCopy,
Alignment, SystemZRegSaveAreaSize);
}
void copyOverflowArea(IRBuilder<> &IRB, Value *VAListTag) {
Type *OverflowArgAreaPtrTy = Type::getInt64PtrTy(*MS.C);
Value *OverflowArgAreaPtrPtr = IRB.CreateIntToPtr(
IRB.CreateAdd(
IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
ConstantInt::get(MS.IntptrTy, SystemZOverflowArgAreaPtrOffset)),
PointerType::get(OverflowArgAreaPtrTy, 0));
Value *OverflowArgAreaPtr =
IRB.CreateLoad(OverflowArgAreaPtrTy, OverflowArgAreaPtrPtr);
Value *OverflowArgAreaShadowPtr, *OverflowArgAreaOriginPtr;
const Align Alignment = Align(8);
std::tie(OverflowArgAreaShadowPtr, OverflowArgAreaOriginPtr) =
MSV.getShadowOriginPtr(OverflowArgAreaPtr, IRB, IRB.getInt8Ty(),
Alignment, /*isStore*/ true);
Value *SrcPtr = IRB.CreateConstGEP1_32(IRB.getInt8Ty(), VAArgTLSCopy,
SystemZOverflowOffset);
IRB.CreateMemCpy(OverflowArgAreaShadowPtr, Alignment, SrcPtr, Alignment,
VAArgOverflowSize);
if (MS.TrackOrigins) {
SrcPtr = IRB.CreateConstGEP1_32(IRB.getInt8Ty(), VAArgTLSOriginCopy,
SystemZOverflowOffset);
IRB.CreateMemCpy(OverflowArgAreaOriginPtr, Alignment, SrcPtr, Alignment,
VAArgOverflowSize);
}
}
void finalizeInstrumentation() override {
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(MSV.ActualFnStart->getFirstNonPHI());
VAArgOverflowSize =
IRB.CreateLoad(IRB.getInt64Ty(), MS.VAArgOverflowSizeTLS);
Value *CopySize =
IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, SystemZOverflowOffset),
VAArgOverflowSize);
VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
IRB.CreateMemCpy(VAArgTLSCopy, Align(8), MS.VAArgTLS, Align(8), CopySize);
if (MS.TrackOrigins) {
VAArgTLSOriginCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
IRB.CreateMemCpy(VAArgTLSOriginCopy, Align(8), MS.VAArgOriginTLS,
Align(8), CopySize);
}
}
// Instrument va_start.
// Copy va_list shadow from the backup copy of the TLS contents.
for (size_t VaStartNo = 0, VaStartNum = VAStartInstrumentationList.size();
VaStartNo < VaStartNum; VaStartNo++) {
CallInst *OrigInst = VAStartInstrumentationList[VaStartNo];
IRBuilder<> IRB(OrigInst->getNextNode());
Value *VAListTag = OrigInst->getArgOperand(0);
copyRegSaveArea(IRB, VAListTag);
copyOverflowArea(IRB, VAListTag);
}
}
};
/// A no-op implementation of VarArgHelper.
struct VarArgNoOpHelper : public VarArgHelper {
VarArgNoOpHelper(Function &F, MemorySanitizer &MS,
MemorySanitizerVisitor &MSV) {}
void visitCallBase(CallBase &CB, IRBuilder<> &IRB) override {}
void visitVAStartInst(VAStartInst &I) override {}
void visitVACopyInst(VACopyInst &I) override {}
void finalizeInstrumentation() override {}
};
} // end anonymous namespace
static VarArgHelper *CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
MemorySanitizerVisitor &Visitor) {
// VarArg handling is only implemented on AMD64. False positives are possible
// on other platforms.
Triple TargetTriple(Func.getParent()->getTargetTriple());
if (TargetTriple.getArch() == Triple::x86_64)
return new VarArgAMD64Helper(Func, Msan, Visitor);
else if (TargetTriple.isMIPS64())
return new VarArgMIPS64Helper(Func, Msan, Visitor);
else if (TargetTriple.getArch() == Triple::aarch64)
return new VarArgAArch64Helper(Func, Msan, Visitor);
else if (TargetTriple.getArch() == Triple::ppc64 ||
TargetTriple.getArch() == Triple::ppc64le)
return new VarArgPowerPC64Helper(Func, Msan, Visitor);
else if (TargetTriple.getArch() == Triple::systemz)
return new VarArgSystemZHelper(Func, Msan, Visitor);
else
return new VarArgNoOpHelper(Func, Msan, Visitor);
}
bool MemorySanitizer::sanitizeFunction(Function &F, TargetLibraryInfo &TLI) {
if (!CompileKernel && F.getName() == kMsanModuleCtorName)
return false;
MemorySanitizerVisitor Visitor(F, *this, TLI);
// Clear out readonly/readnone attributes.
AttrBuilder B;
B.addAttribute(Attribute::ReadOnly)
.addAttribute(Attribute::ReadNone)
.addAttribute(Attribute::WriteOnly)
.addAttribute(Attribute::ArgMemOnly)
.addAttribute(Attribute::Speculatable);
F.removeAttributes(AttributeList::FunctionIndex, B);
return Visitor.runOnFunction();
}
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