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llvm-mirror/lib/Transforms/Instrumentation/MemorySanitizer.cpp
Gui Andrade 7e14b9cae5 [MSAN] Handle x86 {round,min,max}sd intrinsics 
These need special handling over the simple vector intrinsics as they
behave more like a shuffle operation: taking the top half of the vector
from one input, and the bottom half separately. Previously, these were
being handled as though all bits of all operands were combined.

Differential Revision: https://reviews.llvm.org/D82398
2020-06-27 06:46:04 +00:00

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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;
/// 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;
};
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) {
initializeMemorySanitizerLegacyPassPass(*PassRegistry::getPassRegistry());
}
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;
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_with_origin"
: "__msan_warning_with_origin_noreturn";
WarningFn =
M.getOrInsertFunction(WarningFnName, IRB.getVoidTy(), IRB.getInt32Ty());
// 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());
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);
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
// exclusion list 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);
assert(Origin->getType()->isIntegerTy());
IRB.CreateCall(MS.WarningFn, Origin)->setCannotMerge();
// 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 FixedVectorType::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.getParamByValType())
: 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()), FArg.getParamByValType());
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.getCalledOperand(),
{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 FixedVectorType::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);
}
// Instrument _mm_*_sd intrinsics
void handleUnarySdIntrinsic(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Value *First = getShadow(&I, 0);
Value *Second = getShadow(&I, 1);
// High word of first operand, low word of second
Value *Shadow =
IRB.CreateShuffleVector(First, Second, llvm::makeArrayRef<int>({2, 1}));
setShadow(&I, Shadow);
setOriginForNaryOp(I);
}
void handleBinarySdIntrinsic(IntrinsicInst &I) {
IRBuilder<> IRB(&I);
Value *First = getShadow(&I, 0);
Value *Second = getShadow(&I, 1);
Value *OrShadow = IRB.CreateOr(First, Second);
// High word of first operand, low word of both OR'd together
Value *Shadow = IRB.CreateShuffleVector(First, OrShadow,
llvm::makeArrayRef<int>({2, 1}));
setShadow(&I, Shadow);
setOriginForNaryOp(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::x86_sse41_round_sd:
handleUnarySdIntrinsic(I);
break;
case Intrinsic::x86_sse2_max_sd:
case Intrinsic::x86_sse2_min_sd:
handleBinarySdIntrinsic(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(CB.getParamByValType(i));
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->getCalledOperand());
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 = CB.getParamByValType(ArgNo);
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 = CB.getParamByValType(ArgNo);
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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