mirror of
https://github.com/c64scene-ar/llvm-6502.git
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f1af1feeee
Fixed set-but-not-used warnings. Reviewer: gribozavr git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173810 91177308-0d34-0410-b5e6-96231b3b80d8
1956 lines
74 KiB
C++
1956 lines
74 KiB
C++
//===-- MemorySanitizer.cpp - detector of uninitialized reads -------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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/// \file
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/// This file is a part of MemorySanitizer, a detector of uninitialized
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/// reads.
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///
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/// Status: early prototype.
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///
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/// The algorithm of the tool is similar to Memcheck
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/// (http://goo.gl/QKbem). We associate a few shadow bits with every
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/// byte of the application memory, poison the shadow of the malloc-ed
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/// or alloca-ed memory, load the shadow bits on every memory read,
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/// propagate the shadow bits through some of the arithmetic
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/// instruction (including MOV), store the shadow bits on every memory
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/// write, report a bug on some other instructions (e.g. JMP) if the
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/// associated shadow is poisoned.
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///
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/// But there are differences too. The first and the major one:
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/// compiler instrumentation instead of binary instrumentation. This
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/// gives us much better register allocation, possible compiler
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/// optimizations and a fast start-up. But this brings the major issue
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/// as well: msan needs to see all program events, including system
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/// calls and reads/writes in system libraries, so we either need to
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/// compile *everything* with msan or use a binary translation
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/// component (e.g. DynamoRIO) to instrument pre-built libraries.
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/// Another difference from Memcheck is that we use 8 shadow bits per
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/// byte of application memory and use a direct shadow mapping. This
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/// greatly simplifies the instrumentation code and avoids races on
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/// shadow updates (Memcheck is single-threaded so races are not a
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/// concern there. Memcheck uses 2 shadow bits per byte with a slow
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/// path storage that uses 8 bits per byte).
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///
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/// The default value of shadow is 0, which means "clean" (not poisoned).
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///
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/// Every module initializer should call __msan_init to ensure that the
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/// shadow memory is ready. On error, __msan_warning is called. Since
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/// parameters and return values may be passed via registers, we have a
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/// specialized thread-local shadow for return values
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/// (__msan_retval_tls) and parameters (__msan_param_tls).
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///
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/// Origin tracking.
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///
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/// MemorySanitizer can track origins (allocation points) of all uninitialized
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/// values. This behavior is controlled with a flag (msan-track-origins) and is
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/// disabled by default.
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///
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/// Origins are 4-byte values created and interpreted by the runtime library.
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/// They are stored in a second shadow mapping, one 4-byte value for 4 bytes
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/// of application memory. Propagation of origins is basically a bunch of
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/// "select" instructions that pick the origin of a dirty argument, if an
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/// instruction has one.
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///
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/// Every 4 aligned, consecutive bytes of application memory have one origin
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/// value associated with them. If these bytes contain uninitialized data
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/// coming from 2 different allocations, the last store wins. Because of this,
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/// MemorySanitizer reports can show unrelated origins, but this is unlikely in
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/// practice.
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///
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/// Origins are meaningless for fully initialized values, so MemorySanitizer
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/// avoids storing origin to memory when a fully initialized value is stored.
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/// This way it avoids needless overwritting origin of the 4-byte region on
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/// a short (i.e. 1 byte) clean store, and it is also good for performance.
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "msan"
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#include "llvm/Transforms/Instrumentation.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/ValueMap.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/InlineAsm.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/MDBuilder.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/Type.h"
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#include "llvm/InstVisitor.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/BlackList.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include "llvm/Transforms/Utils/ModuleUtils.h"
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using namespace llvm;
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static const uint64_t kShadowMask32 = 1ULL << 31;
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static const uint64_t kShadowMask64 = 1ULL << 46;
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static const uint64_t kOriginOffset32 = 1ULL << 30;
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static const uint64_t kOriginOffset64 = 1ULL << 45;
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static const unsigned kMinOriginAlignment = 4;
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static const unsigned kShadowTLSAlignment = 8;
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/// \brief Track origins of uninitialized values.
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///
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/// Adds a section to MemorySanitizer report that points to the allocation
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/// (stack or heap) the uninitialized bits came from originally.
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static cl::opt<bool> ClTrackOrigins("msan-track-origins",
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cl::desc("Track origins (allocation sites) of poisoned memory"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClKeepGoing("msan-keep-going",
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cl::desc("keep going after reporting a UMR"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClPoisonStack("msan-poison-stack",
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cl::desc("poison uninitialized stack variables"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClPoisonStackWithCall("msan-poison-stack-with-call",
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cl::desc("poison uninitialized stack variables with a call"),
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cl::Hidden, cl::init(false));
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static cl::opt<int> ClPoisonStackPattern("msan-poison-stack-pattern",
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cl::desc("poison uninitialized stack variables with the given patter"),
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cl::Hidden, cl::init(0xff));
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static cl::opt<bool> ClHandleICmp("msan-handle-icmp",
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cl::desc("propagate shadow through ICmpEQ and ICmpNE"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClHandleICmpExact("msan-handle-icmp-exact",
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cl::desc("exact handling of relational integer ICmp"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClStoreCleanOrigin("msan-store-clean-origin",
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cl::desc("store origin for clean (fully initialized) values"),
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cl::Hidden, cl::init(false));
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// This flag controls whether we check the shadow of the address
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// operand of load or store. Such bugs are very rare, since load from
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// a garbage address typically results in SEGV, but still happen
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// (e.g. only lower bits of address are garbage, or the access happens
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// early at program startup where malloc-ed memory is more likely to
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// be zeroed. As of 2012-08-28 this flag adds 20% slowdown.
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static cl::opt<bool> ClCheckAccessAddress("msan-check-access-address",
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cl::desc("report accesses through a pointer which has poisoned shadow"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClDumpStrictInstructions("msan-dump-strict-instructions",
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cl::desc("print out instructions with default strict semantics"),
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cl::Hidden, cl::init(false));
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static cl::opt<std::string> ClBlacklistFile("msan-blacklist",
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cl::desc("File containing the list of functions where MemorySanitizer "
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"should not report bugs"), cl::Hidden);
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namespace {
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/// \brief An instrumentation pass implementing detection of uninitialized
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/// reads.
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///
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/// MemorySanitizer: instrument the code in module to find
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/// uninitialized reads.
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class MemorySanitizer : public FunctionPass {
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public:
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MemorySanitizer(bool TrackOrigins = false,
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StringRef BlacklistFile = StringRef())
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: FunctionPass(ID),
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TrackOrigins(TrackOrigins || ClTrackOrigins),
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TD(0),
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WarningFn(0),
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BlacklistFile(BlacklistFile.empty() ? ClBlacklistFile
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: BlacklistFile) { }
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const char *getPassName() const { return "MemorySanitizer"; }
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bool runOnFunction(Function &F);
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bool doInitialization(Module &M);
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static char ID; // Pass identification, replacement for typeid.
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private:
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void initializeCallbacks(Module &M);
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/// \brief Track origins (allocation points) of uninitialized values.
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bool TrackOrigins;
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DataLayout *TD;
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LLVMContext *C;
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Type *IntptrTy;
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Type *OriginTy;
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/// \brief Thread-local shadow storage for function parameters.
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GlobalVariable *ParamTLS;
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/// \brief Thread-local origin storage for function parameters.
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GlobalVariable *ParamOriginTLS;
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/// \brief Thread-local shadow storage for function return value.
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GlobalVariable *RetvalTLS;
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/// \brief Thread-local origin storage for function return value.
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GlobalVariable *RetvalOriginTLS;
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/// \brief Thread-local shadow storage for in-register va_arg function
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/// parameters (x86_64-specific).
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GlobalVariable *VAArgTLS;
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/// \brief Thread-local shadow storage for va_arg overflow area
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/// (x86_64-specific).
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GlobalVariable *VAArgOverflowSizeTLS;
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/// \brief Thread-local space used to pass origin value to the UMR reporting
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/// function.
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GlobalVariable *OriginTLS;
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/// \brief The run-time callback to print a warning.
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Value *WarningFn;
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/// \brief Run-time helper that copies origin info for a memory range.
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Value *MsanCopyOriginFn;
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/// \brief Run-time helper that generates a new origin value for a stack
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/// allocation.
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Value *MsanSetAllocaOriginFn;
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/// \brief Run-time helper that poisons stack on function entry.
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Value *MsanPoisonStackFn;
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/// \brief MSan runtime replacements for memmove, memcpy and memset.
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Value *MemmoveFn, *MemcpyFn, *MemsetFn;
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/// \brief Address mask used in application-to-shadow address calculation.
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/// ShadowAddr is computed as ApplicationAddr & ~ShadowMask.
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uint64_t ShadowMask;
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/// \brief Offset of the origin shadow from the "normal" shadow.
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/// OriginAddr is computed as (ShadowAddr + OriginOffset) & ~3ULL
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uint64_t OriginOffset;
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/// \brief Branch weights for error reporting.
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MDNode *ColdCallWeights;
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/// \brief Branch weights for origin store.
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MDNode *OriginStoreWeights;
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/// \bried Path to blacklist file.
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SmallString<64> BlacklistFile;
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/// \brief The blacklist.
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OwningPtr<BlackList> BL;
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/// \brief An empty volatile inline asm that prevents callback merge.
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InlineAsm *EmptyAsm;
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friend struct MemorySanitizerVisitor;
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friend struct VarArgAMD64Helper;
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};
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} // namespace
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char MemorySanitizer::ID = 0;
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INITIALIZE_PASS(MemorySanitizer, "msan",
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"MemorySanitizer: detects uninitialized reads.",
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false, false)
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FunctionPass *llvm::createMemorySanitizerPass(bool TrackOrigins,
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StringRef BlacklistFile) {
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return new MemorySanitizer(TrackOrigins, BlacklistFile);
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}
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/// \brief Create a non-const global initialized with the given string.
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///
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/// Creates a writable global for Str so that we can pass it to the
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/// run-time lib. Runtime uses first 4 bytes of the string to store the
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/// frame ID, so the string needs to be mutable.
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static GlobalVariable *createPrivateNonConstGlobalForString(Module &M,
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StringRef Str) {
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Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
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return new GlobalVariable(M, StrConst->getType(), /*isConstant=*/false,
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GlobalValue::PrivateLinkage, StrConst, "");
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}
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/// \brief Insert extern declaration of runtime-provided functions and globals.
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void MemorySanitizer::initializeCallbacks(Module &M) {
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// Only do this once.
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if (WarningFn)
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return;
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IRBuilder<> IRB(*C);
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// Create the callback.
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// FIXME: this function should have "Cold" calling conv,
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// which is not yet implemented.
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StringRef WarningFnName = ClKeepGoing ? "__msan_warning"
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: "__msan_warning_noreturn";
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WarningFn = M.getOrInsertFunction(WarningFnName, IRB.getVoidTy(), NULL);
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MsanCopyOriginFn = M.getOrInsertFunction(
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"__msan_copy_origin", IRB.getVoidTy(), IRB.getInt8PtrTy(),
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IRB.getInt8PtrTy(), IntptrTy, NULL);
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MsanSetAllocaOriginFn = M.getOrInsertFunction(
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"__msan_set_alloca_origin", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy,
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IRB.getInt8PtrTy(), NULL);
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MsanPoisonStackFn = M.getOrInsertFunction(
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"__msan_poison_stack", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy, NULL);
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MemmoveFn = M.getOrInsertFunction(
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"__msan_memmove", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
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IRB.getInt8PtrTy(), IntptrTy, NULL);
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MemcpyFn = M.getOrInsertFunction(
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"__msan_memcpy", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
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IntptrTy, NULL);
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MemsetFn = M.getOrInsertFunction(
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"__msan_memset", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt32Ty(),
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IntptrTy, NULL);
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// Create globals.
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RetvalTLS = new GlobalVariable(
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M, ArrayType::get(IRB.getInt64Ty(), 8), false,
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GlobalVariable::ExternalLinkage, 0, "__msan_retval_tls", 0,
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GlobalVariable::GeneralDynamicTLSModel);
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RetvalOriginTLS = new GlobalVariable(
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M, OriginTy, false, GlobalVariable::ExternalLinkage, 0,
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"__msan_retval_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel);
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ParamTLS = new GlobalVariable(
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M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
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GlobalVariable::ExternalLinkage, 0, "__msan_param_tls", 0,
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GlobalVariable::GeneralDynamicTLSModel);
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ParamOriginTLS = new GlobalVariable(
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M, ArrayType::get(OriginTy, 1000), false, GlobalVariable::ExternalLinkage,
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0, "__msan_param_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel);
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VAArgTLS = new GlobalVariable(
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M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
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GlobalVariable::ExternalLinkage, 0, "__msan_va_arg_tls", 0,
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GlobalVariable::GeneralDynamicTLSModel);
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VAArgOverflowSizeTLS = new GlobalVariable(
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M, IRB.getInt64Ty(), false, GlobalVariable::ExternalLinkage, 0,
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"__msan_va_arg_overflow_size_tls", 0,
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GlobalVariable::GeneralDynamicTLSModel);
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OriginTLS = new GlobalVariable(
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M, IRB.getInt32Ty(), false, GlobalVariable::ExternalLinkage, 0,
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"__msan_origin_tls", 0, GlobalVariable::GeneralDynamicTLSModel);
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// We insert an empty inline asm after __msan_report* to avoid callback merge.
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EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
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StringRef(""), StringRef(""),
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/*hasSideEffects=*/true);
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}
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/// \brief Module-level initialization.
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///
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/// inserts a call to __msan_init to the module's constructor list.
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bool MemorySanitizer::doInitialization(Module &M) {
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TD = getAnalysisIfAvailable<DataLayout>();
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if (!TD)
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return false;
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BL.reset(new BlackList(BlacklistFile));
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C = &(M.getContext());
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unsigned PtrSize = TD->getPointerSizeInBits(/* AddressSpace */0);
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switch (PtrSize) {
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case 64:
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ShadowMask = kShadowMask64;
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OriginOffset = kOriginOffset64;
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break;
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case 32:
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ShadowMask = kShadowMask32;
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OriginOffset = kOriginOffset32;
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break;
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default:
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report_fatal_error("unsupported pointer size");
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break;
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}
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IRBuilder<> IRB(*C);
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IntptrTy = IRB.getIntPtrTy(TD);
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OriginTy = IRB.getInt32Ty();
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ColdCallWeights = MDBuilder(*C).createBranchWeights(1, 1000);
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OriginStoreWeights = MDBuilder(*C).createBranchWeights(1, 1000);
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// Insert a call to __msan_init/__msan_track_origins into the module's CTORs.
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appendToGlobalCtors(M, cast<Function>(M.getOrInsertFunction(
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"__msan_init", IRB.getVoidTy(), NULL)), 0);
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new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
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IRB.getInt32(TrackOrigins), "__msan_track_origins");
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new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
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IRB.getInt32(ClKeepGoing), "__msan_keep_going");
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return true;
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}
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namespace {
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/// \brief A helper class that handles instrumentation of VarArg
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/// functions on a particular platform.
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///
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/// Implementations are expected to insert the instrumentation
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/// necessary to propagate argument shadow through VarArg function
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/// calls. Visit* methods are called during an InstVisitor pass over
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/// the function, and should avoid creating new basic blocks. A new
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/// instance of this class is created for each instrumented function.
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struct VarArgHelper {
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/// \brief Visit a CallSite.
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virtual void visitCallSite(CallSite &CS, IRBuilder<> &IRB) = 0;
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/// \brief Visit a va_start call.
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virtual void visitVAStartInst(VAStartInst &I) = 0;
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/// \brief Visit a va_copy call.
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virtual void visitVACopyInst(VACopyInst &I) = 0;
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/// \brief Finalize function instrumentation.
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///
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/// This method is called after visiting all interesting (see above)
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/// instructions in a function.
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virtual void finalizeInstrumentation() = 0;
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virtual ~VarArgHelper() {}
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};
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struct MemorySanitizerVisitor;
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VarArgHelper*
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CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
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MemorySanitizerVisitor &Visitor);
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/// This class does all the work for a given function. Store and Load
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/// instructions store and load corresponding shadow and origin
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/// values. Most instructions propagate shadow from arguments to their
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/// return values. Certain instructions (most importantly, BranchInst)
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/// test their argument shadow and print reports (with a runtime call) if it's
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/// non-zero.
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struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
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Function &F;
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MemorySanitizer &MS;
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SmallVector<PHINode *, 16> ShadowPHINodes, OriginPHINodes;
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ValueMap<Value*, Value*> ShadowMap, OriginMap;
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bool InsertChecks;
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OwningPtr<VarArgHelper> VAHelper;
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// An unfortunate workaround for asymmetric lowering of va_arg stuff.
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// See a comment in visitCallSite for more details.
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static const unsigned AMD64GpEndOffset = 48; // AMD64 ABI Draft 0.99.6 p3.5.7
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static const unsigned AMD64FpEndOffset = 176;
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struct ShadowOriginAndInsertPoint {
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Instruction *Shadow;
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Instruction *Origin;
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Instruction *OrigIns;
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ShadowOriginAndInsertPoint(Instruction *S, Instruction *O, Instruction *I)
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: Shadow(S), Origin(O), OrigIns(I) { }
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ShadowOriginAndInsertPoint() : Shadow(0), Origin(0), OrigIns(0) { }
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};
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SmallVector<ShadowOriginAndInsertPoint, 16> InstrumentationList;
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SmallVector<Instruction*, 16> StoreList;
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MemorySanitizerVisitor(Function &F, MemorySanitizer &MS)
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: F(F), MS(MS), VAHelper(CreateVarArgHelper(F, MS, *this)) {
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InsertChecks = !MS.BL->isIn(F);
|
|
DEBUG(if (!InsertChecks)
|
|
dbgs() << "MemorySanitizer is not inserting checks into '"
|
|
<< F.getName() << "'\n");
|
|
}
|
|
|
|
void materializeStores() {
|
|
for (size_t i = 0, n = StoreList.size(); i < n; i++) {
|
|
StoreInst& I = *dyn_cast<StoreInst>(StoreList[i]);
|
|
|
|
IRBuilder<> IRB(&I);
|
|
Value *Val = I.getValueOperand();
|
|
Value *Addr = I.getPointerOperand();
|
|
Value *Shadow = getShadow(Val);
|
|
Value *ShadowPtr = getShadowPtr(Addr, Shadow->getType(), IRB);
|
|
|
|
StoreInst *NewSI =
|
|
IRB.CreateAlignedStore(Shadow, ShadowPtr, I.getAlignment());
|
|
DEBUG(dbgs() << " STORE: " << *NewSI << "\n");
|
|
(void)NewSI;
|
|
|
|
if (ClCheckAccessAddress)
|
|
insertCheck(Addr, &I);
|
|
|
|
if (MS.TrackOrigins) {
|
|
unsigned Alignment = std::max(kMinOriginAlignment, I.getAlignment());
|
|
if (ClStoreCleanOrigin || isa<StructType>(Shadow->getType())) {
|
|
IRB.CreateAlignedStore(getOrigin(Val), getOriginPtr(Addr, IRB),
|
|
Alignment);
|
|
} else {
|
|
Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
|
|
|
|
Constant *Cst = dyn_cast_or_null<Constant>(ConvertedShadow);
|
|
// TODO(eugenis): handle non-zero constant shadow by inserting an
|
|
// unconditional check (can not simply fail compilation as this could
|
|
// be in the dead code).
|
|
if (Cst)
|
|
continue;
|
|
|
|
Value *Cmp = IRB.CreateICmpNE(ConvertedShadow,
|
|
getCleanShadow(ConvertedShadow), "_mscmp");
|
|
Instruction *CheckTerm =
|
|
SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false,
|
|
MS.OriginStoreWeights);
|
|
IRBuilder<> IRBNew(CheckTerm);
|
|
IRBNew.CreateAlignedStore(getOrigin(Val), getOriginPtr(Addr, IRBNew),
|
|
Alignment);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void materializeChecks() {
|
|
for (size_t i = 0, n = InstrumentationList.size(); i < n; i++) {
|
|
Instruction *Shadow = InstrumentationList[i].Shadow;
|
|
Instruction *OrigIns = InstrumentationList[i].OrigIns;
|
|
IRBuilder<> IRB(OrigIns);
|
|
DEBUG(dbgs() << " SHAD0 : " << *Shadow << "\n");
|
|
Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
|
|
DEBUG(dbgs() << " SHAD1 : " << *ConvertedShadow << "\n");
|
|
Value *Cmp = IRB.CreateICmpNE(ConvertedShadow,
|
|
getCleanShadow(ConvertedShadow), "_mscmp");
|
|
Instruction *CheckTerm =
|
|
SplitBlockAndInsertIfThen(cast<Instruction>(Cmp),
|
|
/* Unreachable */ !ClKeepGoing,
|
|
MS.ColdCallWeights);
|
|
|
|
IRB.SetInsertPoint(CheckTerm);
|
|
if (MS.TrackOrigins) {
|
|
Instruction *Origin = InstrumentationList[i].Origin;
|
|
IRB.CreateStore(Origin ? (Value*)Origin : (Value*)IRB.getInt32(0),
|
|
MS.OriginTLS);
|
|
}
|
|
CallInst *Call = IRB.CreateCall(MS.WarningFn);
|
|
Call->setDebugLoc(OrigIns->getDebugLoc());
|
|
IRB.CreateCall(MS.EmptyAsm);
|
|
DEBUG(dbgs() << " CHECK: " << *Cmp << "\n");
|
|
}
|
|
DEBUG(dbgs() << "DONE:\n" << F);
|
|
}
|
|
|
|
/// \brief Add MemorySanitizer instrumentation to a function.
|
|
bool runOnFunction() {
|
|
MS.initializeCallbacks(*F.getParent());
|
|
if (!MS.TD) return false;
|
|
|
|
// 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 (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
|
|
DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) {
|
|
BasicBlock *BB = *DI;
|
|
visit(*BB);
|
|
}
|
|
|
|
// Finalize PHI nodes.
|
|
for (size_t i = 0, n = ShadowPHINodes.size(); i < n; i++) {
|
|
PHINode *PN = ShadowPHINodes[i];
|
|
PHINode *PNS = cast<PHINode>(getShadow(PN));
|
|
PHINode *PNO = MS.TrackOrigins ? cast<PHINode>(getOrigin(PN)) : 0;
|
|
size_t NumValues = PN->getNumIncomingValues();
|
|
for (size_t v = 0; v < NumValues; v++) {
|
|
PNS->addIncoming(getShadow(PN, v), PN->getIncomingBlock(v));
|
|
if (PNO)
|
|
PNO->addIncoming(getOrigin(PN, v), PN->getIncomingBlock(v));
|
|
}
|
|
}
|
|
|
|
VAHelper->finalizeInstrumentation();
|
|
|
|
// Delayed instrumentation of StoreInst.
|
|
// This may add new checks to be inserted later.
|
|
materializeStores();
|
|
|
|
// Insert shadow value checks.
|
|
materializeChecks();
|
|
|
|
return true;
|
|
}
|
|
|
|
/// \brief Compute the shadow type that corresponds to a given Value.
|
|
Type *getShadowTy(Value *V) {
|
|
return getShadowTy(V->getType());
|
|
}
|
|
|
|
/// \brief Compute the shadow type that corresponds to a given Type.
|
|
Type *getShadowTy(Type *OrigTy) {
|
|
if (!OrigTy->isSized()) {
|
|
return 0;
|
|
}
|
|
// For integer type, shadow is the same as the original type.
|
|
// This may return weird-sized types like i1.
|
|
if (IntegerType *IT = dyn_cast<IntegerType>(OrigTy))
|
|
return IT;
|
|
if (VectorType *VT = dyn_cast<VectorType>(OrigTy)) {
|
|
uint32_t EltSize = MS.TD->getTypeSizeInBits(VT->getElementType());
|
|
return VectorType::get(IntegerType::get(*MS.C, EltSize),
|
|
VT->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());
|
|
DEBUG(dbgs() << "getShadowTy: " << *ST << " ===> " << *Res << "\n");
|
|
return Res;
|
|
}
|
|
uint32_t TypeSize = MS.TD->getTypeSizeInBits(OrigTy);
|
|
return IntegerType::get(*MS.C, TypeSize);
|
|
}
|
|
|
|
/// \brief Flatten a vector type.
|
|
Type *getShadowTyNoVec(Type *ty) {
|
|
if (VectorType *vt = dyn_cast<VectorType>(ty))
|
|
return IntegerType::get(*MS.C, vt->getBitWidth());
|
|
return ty;
|
|
}
|
|
|
|
/// \brief Convert a shadow value to it's flattened variant.
|
|
Value *convertToShadowTyNoVec(Value *V, IRBuilder<> &IRB) {
|
|
Type *Ty = V->getType();
|
|
Type *NoVecTy = getShadowTyNoVec(Ty);
|
|
if (Ty == NoVecTy) return V;
|
|
return IRB.CreateBitCast(V, NoVecTy);
|
|
}
|
|
|
|
/// \brief Compute the shadow address that corresponds to a given application
|
|
/// address.
|
|
///
|
|
/// Shadow = Addr & ~ShadowMask.
|
|
Value *getShadowPtr(Value *Addr, Type *ShadowTy,
|
|
IRBuilder<> &IRB) {
|
|
Value *ShadowLong =
|
|
IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
|
|
ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask));
|
|
return IRB.CreateIntToPtr(ShadowLong, PointerType::get(ShadowTy, 0));
|
|
}
|
|
|
|
/// \brief Compute the origin address that corresponds to a given application
|
|
/// address.
|
|
///
|
|
/// OriginAddr = (ShadowAddr + OriginOffset) & ~3ULL
|
|
Value *getOriginPtr(Value *Addr, IRBuilder<> &IRB) {
|
|
Value *ShadowLong =
|
|
IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy),
|
|
ConstantInt::get(MS.IntptrTy, ~MS.ShadowMask));
|
|
Value *Add =
|
|
IRB.CreateAdd(ShadowLong,
|
|
ConstantInt::get(MS.IntptrTy, MS.OriginOffset));
|
|
Value *SecondAnd =
|
|
IRB.CreateAnd(Add, ConstantInt::get(MS.IntptrTy, ~3ULL));
|
|
return IRB.CreateIntToPtr(SecondAnd, PointerType::get(IRB.getInt32Ty(), 0));
|
|
}
|
|
|
|
/// \brief Compute the shadow address for a given function argument.
|
|
///
|
|
/// Shadow = ParamTLS+ArgOffset.
|
|
Value *getShadowPtrForArgument(Value *A, IRBuilder<> &IRB,
|
|
int ArgOffset) {
|
|
Value *Base = IRB.CreatePointerCast(MS.ParamTLS, MS.IntptrTy);
|
|
Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
|
|
return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A), 0),
|
|
"_msarg");
|
|
}
|
|
|
|
/// \brief Compute the origin address for a given function argument.
|
|
Value *getOriginPtrForArgument(Value *A, IRBuilder<> &IRB,
|
|
int ArgOffset) {
|
|
if (!MS.TrackOrigins) return 0;
|
|
Value *Base = IRB.CreatePointerCast(MS.ParamOriginTLS, MS.IntptrTy);
|
|
Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
|
|
return IRB.CreateIntToPtr(Base, PointerType::get(MS.OriginTy, 0),
|
|
"_msarg_o");
|
|
}
|
|
|
|
/// \brief Compute the shadow address for a retval.
|
|
Value *getShadowPtrForRetval(Value *A, IRBuilder<> &IRB) {
|
|
Value *Base = IRB.CreatePointerCast(MS.RetvalTLS, MS.IntptrTy);
|
|
return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A), 0),
|
|
"_msret");
|
|
}
|
|
|
|
/// \brief Compute the origin address for a retval.
|
|
Value *getOriginPtrForRetval(IRBuilder<> &IRB) {
|
|
// We keep a single origin for the entire retval. Might be too optimistic.
|
|
return MS.RetvalOriginTLS;
|
|
}
|
|
|
|
/// \brief Set SV to be the shadow value for V.
|
|
void setShadow(Value *V, Value *SV) {
|
|
assert(!ShadowMap.count(V) && "Values may only have one shadow");
|
|
ShadowMap[V] = SV;
|
|
}
|
|
|
|
/// \brief Set Origin to be the origin value for V.
|
|
void setOrigin(Value *V, Value *Origin) {
|
|
if (!MS.TrackOrigins) return;
|
|
assert(!OriginMap.count(V) && "Values may only have one origin");
|
|
DEBUG(dbgs() << "ORIGIN: " << *V << " ==> " << *Origin << "\n");
|
|
OriginMap[V] = Origin;
|
|
}
|
|
|
|
/// \brief Create a clean shadow value for a given value.
|
|
///
|
|
/// Clean shadow (all zeroes) means all bits of the value are defined
|
|
/// (initialized).
|
|
Value *getCleanShadow(Value *V) {
|
|
Type *ShadowTy = getShadowTy(V);
|
|
if (!ShadowTy)
|
|
return 0;
|
|
return Constant::getNullValue(ShadowTy);
|
|
}
|
|
|
|
/// \brief Create a dirty shadow of a given shadow type.
|
|
Constant *getPoisonedShadow(Type *ShadowTy) {
|
|
assert(ShadowTy);
|
|
if (isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy))
|
|
return Constant::getAllOnesValue(ShadowTy);
|
|
StructType *ST = cast<StructType>(ShadowTy);
|
|
SmallVector<Constant *, 4> Vals;
|
|
for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
|
|
Vals.push_back(getPoisonedShadow(ST->getElementType(i)));
|
|
return ConstantStruct::get(ST, Vals);
|
|
}
|
|
|
|
/// \brief Create a clean (zero) origin.
|
|
Value *getCleanOrigin() {
|
|
return Constant::getNullValue(MS.OriginTy);
|
|
}
|
|
|
|
/// \brief Get the shadow value for a given Value.
|
|
///
|
|
/// This function either returns the value set earlier with setShadow,
|
|
/// or extracts if from ParamTLS (for function arguments).
|
|
Value *getShadow(Value *V) {
|
|
if (Instruction *I = dyn_cast<Instruction>(V)) {
|
|
// For instructions the shadow is already stored in the map.
|
|
Value *Shadow = ShadowMap[V];
|
|
if (!Shadow) {
|
|
DEBUG(dbgs() << "No shadow: " << *V << "\n" << *(I->getParent()));
|
|
(void)I;
|
|
assert(Shadow && "No shadow for a value");
|
|
}
|
|
return Shadow;
|
|
}
|
|
if (UndefValue *U = dyn_cast<UndefValue>(V)) {
|
|
Value *AllOnes = getPoisonedShadow(getShadowTy(V));
|
|
DEBUG(dbgs() << "Undef: " << *U << " ==> " << *AllOnes << "\n");
|
|
(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(F->getEntryBlock().getFirstNonPHI());
|
|
unsigned ArgOffset = 0;
|
|
for (Function::arg_iterator AI = F->arg_begin(), AE = F->arg_end();
|
|
AI != AE; ++AI) {
|
|
if (!AI->getType()->isSized()) {
|
|
DEBUG(dbgs() << "Arg is not sized\n");
|
|
continue;
|
|
}
|
|
unsigned Size = AI->hasByValAttr()
|
|
? MS.TD->getTypeAllocSize(AI->getType()->getPointerElementType())
|
|
: MS.TD->getTypeAllocSize(AI->getType());
|
|
if (A == AI) {
|
|
Value *Base = getShadowPtrForArgument(AI, EntryIRB, ArgOffset);
|
|
if (AI->hasByValAttr()) {
|
|
// ByVal pointer itself has clean shadow. We copy the actual
|
|
// argument shadow to the underlying memory.
|
|
Value *Cpy = EntryIRB.CreateMemCpy(
|
|
getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB),
|
|
Base, Size, AI->getParamAlignment());
|
|
DEBUG(dbgs() << " ByValCpy: " << *Cpy << "\n");
|
|
(void)Cpy;
|
|
*ShadowPtr = getCleanShadow(V);
|
|
} else {
|
|
*ShadowPtr = EntryIRB.CreateLoad(Base);
|
|
}
|
|
DEBUG(dbgs() << " ARG: " << *AI << " ==> " <<
|
|
**ShadowPtr << "\n");
|
|
if (MS.TrackOrigins) {
|
|
Value* OriginPtr = getOriginPtrForArgument(AI, EntryIRB, ArgOffset);
|
|
setOrigin(A, EntryIRB.CreateLoad(OriginPtr));
|
|
}
|
|
}
|
|
ArgOffset += DataLayout::RoundUpAlignment(Size, 8);
|
|
}
|
|
assert(*ShadowPtr && "Could not find shadow for an argument");
|
|
return *ShadowPtr;
|
|
}
|
|
// For everything else the shadow is zero.
|
|
return getCleanShadow(V);
|
|
}
|
|
|
|
/// \brief Get the shadow for i-th argument of the instruction I.
|
|
Value *getShadow(Instruction *I, int i) {
|
|
return getShadow(I->getOperand(i));
|
|
}
|
|
|
|
/// \brief Get the origin for a value.
|
|
Value *getOrigin(Value *V) {
|
|
if (!MS.TrackOrigins) return 0;
|
|
if (isa<Instruction>(V) || isa<Argument>(V)) {
|
|
Value *Origin = OriginMap[V];
|
|
if (!Origin) {
|
|
DEBUG(dbgs() << "NO ORIGIN: " << *V << "\n");
|
|
Origin = getCleanOrigin();
|
|
}
|
|
return Origin;
|
|
}
|
|
return getCleanOrigin();
|
|
}
|
|
|
|
/// \brief Get the origin for i-th argument of the instruction I.
|
|
Value *getOrigin(Instruction *I, int i) {
|
|
return getOrigin(I->getOperand(i));
|
|
}
|
|
|
|
/// \brief Remember the place where a shadow check should be inserted.
|
|
///
|
|
/// This location will be later instrumented with a check that will print a
|
|
/// UMR warning in runtime if the value is not fully defined.
|
|
void insertCheck(Value *Val, Instruction *OrigIns) {
|
|
assert(Val);
|
|
if (!InsertChecks) return;
|
|
Instruction *Shadow = dyn_cast_or_null<Instruction>(getShadow(Val));
|
|
if (!Shadow) return;
|
|
#ifndef NDEBUG
|
|
Type *ShadowTy = Shadow->getType();
|
|
assert((isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy)) &&
|
|
"Can only insert checks for integer and vector shadow types");
|
|
#endif
|
|
Instruction *Origin = dyn_cast_or_null<Instruction>(getOrigin(Val));
|
|
InstrumentationList.push_back(
|
|
ShadowOriginAndInsertPoint(Shadow, Origin, OrigIns));
|
|
}
|
|
|
|
// ------------------- Visitors.
|
|
|
|
/// \brief Instrument LoadInst
|
|
///
|
|
/// Loads the corresponding shadow and (optionally) origin.
|
|
/// Optionally, checks that the load address is fully defined.
|
|
void visitLoadInst(LoadInst &I) {
|
|
assert(I.getType()->isSized() && "Load type must have size");
|
|
IRBuilder<> IRB(&I);
|
|
Type *ShadowTy = getShadowTy(&I);
|
|
Value *Addr = I.getPointerOperand();
|
|
Value *ShadowPtr = getShadowPtr(Addr, ShadowTy, IRB);
|
|
setShadow(&I, IRB.CreateAlignedLoad(ShadowPtr, I.getAlignment(), "_msld"));
|
|
|
|
if (ClCheckAccessAddress)
|
|
insertCheck(I.getPointerOperand(), &I);
|
|
|
|
if (MS.TrackOrigins) {
|
|
unsigned Alignment = std::max(kMinOriginAlignment, I.getAlignment());
|
|
setOrigin(&I, IRB.CreateAlignedLoad(getOriginPtr(Addr, IRB), Alignment));
|
|
}
|
|
}
|
|
|
|
/// \brief 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);
|
|
}
|
|
|
|
// Vector manipulation.
|
|
void visitExtractElementInst(ExtractElementInst &I) {
|
|
insertCheck(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) {
|
|
insertCheck(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) {
|
|
insertCheck(I.getOperand(2), &I);
|
|
IRBuilder<> IRB(&I);
|
|
setShadow(&I, IRB.CreateShuffleVector(getShadow(&I, 0), getShadow(&I, 1),
|
|
I.getOperand(2), "_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) {
|
|
IRBuilder<> IRB(&I);
|
|
setShadow(&I, IRB.CreateBitCast(getShadow(&I, 0), getShadowTy(&I)));
|
|
setOrigin(&I, getOrigin(&I, 0));
|
|
}
|
|
|
|
void visitPtrToIntInst(PtrToIntInst &I) {
|
|
IRBuilder<> IRB(&I);
|
|
setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I), false,
|
|
"_msprop_ptrtoint"));
|
|
setOrigin(&I, getOrigin(&I, 0));
|
|
}
|
|
|
|
void visitIntToPtrInst(IntToPtrInst &I) {
|
|
IRBuilder<> IRB(&I);
|
|
setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I), false,
|
|
"_msprop_inttoptr"));
|
|
setOrigin(&I, getOrigin(&I, 0));
|
|
}
|
|
|
|
void visitFPToSIInst(CastInst& I) { handleShadowOr(I); }
|
|
void visitFPToUIInst(CastInst& I) { handleShadowOr(I); }
|
|
void visitSIToFPInst(CastInst& I) { handleShadowOr(I); }
|
|
void visitUIToFPInst(CastInst& I) { handleShadowOr(I); }
|
|
void visitFPExtInst(CastInst& I) { handleShadowOr(I); }
|
|
void visitFPTruncInst(CastInst& I) { handleShadowOr(I); }
|
|
|
|
/// \brief Propagate shadow for bitwise AND.
|
|
///
|
|
/// This code is exact, i.e. if, for example, a bit in the left argument
|
|
/// is defined and 0, then neither the value not definedness of the
|
|
/// corresponding bit in B don't affect the resulting shadow.
|
|
void visitAnd(BinaryOperator &I) {
|
|
IRBuilder<> IRB(&I);
|
|
// "And" of 0 and a poisoned value results in unpoisoned value.
|
|
// 1&1 => 1; 0&1 => 0; p&1 => p;
|
|
// 1&0 => 0; 0&0 => 0; p&0 => 0;
|
|
// 1&p => p; 0&p => 0; p&p => p;
|
|
// S = (S1 & S2) | (V1 & S2) | (S1 & V2)
|
|
Value *S1 = getShadow(&I, 0);
|
|
Value *S2 = getShadow(&I, 1);
|
|
Value *V1 = I.getOperand(0);
|
|
Value *V2 = I.getOperand(1);
|
|
if (V1->getType() != S1->getType()) {
|
|
V1 = IRB.CreateIntCast(V1, S1->getType(), false);
|
|
V2 = IRB.CreateIntCast(V2, S2->getType(), false);
|
|
}
|
|
Value *S1S2 = IRB.CreateAnd(S1, S2);
|
|
Value *V1S2 = IRB.CreateAnd(V1, S2);
|
|
Value *S1V2 = IRB.CreateAnd(S1, V2);
|
|
setShadow(&I, IRB.CreateOr(S1S2, IRB.CreateOr(V1S2, S1V2)));
|
|
setOriginForNaryOp(I);
|
|
}
|
|
|
|
void visitOr(BinaryOperator &I) {
|
|
IRBuilder<> IRB(&I);
|
|
// "Or" of 1 and a poisoned value results in unpoisoned value.
|
|
// 1|1 => 1; 0|1 => 1; p|1 => 1;
|
|
// 1|0 => 1; 0|0 => 0; p|0 => p;
|
|
// 1|p => 1; 0|p => p; p|p => p;
|
|
// S = (S1 & S2) | (~V1 & S2) | (S1 & ~V2)
|
|
Value *S1 = getShadow(&I, 0);
|
|
Value *S2 = getShadow(&I, 1);
|
|
Value *V1 = IRB.CreateNot(I.getOperand(0));
|
|
Value *V2 = IRB.CreateNot(I.getOperand(1));
|
|
if (V1->getType() != S1->getType()) {
|
|
V1 = IRB.CreateIntCast(V1, S1->getType(), false);
|
|
V2 = IRB.CreateIntCast(V2, S2->getType(), false);
|
|
}
|
|
Value *S1S2 = IRB.CreateAnd(S1, S2);
|
|
Value *V1S2 = IRB.CreateAnd(V1, S2);
|
|
Value *S1V2 = IRB.CreateAnd(S1, V2);
|
|
setShadow(&I, IRB.CreateOr(S1S2, IRB.CreateOr(V1S2, S1V2)));
|
|
setOriginForNaryOp(I);
|
|
}
|
|
|
|
/// \brief 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;
|
|
Value *Origin;
|
|
IRBuilder<> &IRB;
|
|
MemorySanitizerVisitor *MSV;
|
|
|
|
public:
|
|
Combiner(MemorySanitizerVisitor *MSV, IRBuilder<> &IRB) :
|
|
Shadow(0), Origin(0), IRB(IRB), MSV(MSV) {}
|
|
|
|
/// \brief 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 {
|
|
Value *FlatShadow = MSV->convertToShadowTyNoVec(OpShadow, IRB);
|
|
Value *Cond = IRB.CreateICmpNE(FlatShadow,
|
|
MSV->getCleanShadow(FlatShadow));
|
|
Origin = IRB.CreateSelect(Cond, OpOrigin, Origin);
|
|
}
|
|
}
|
|
return *this;
|
|
}
|
|
|
|
/// \brief Add an application value to the mix.
|
|
Combiner &Add(Value *V) {
|
|
Value *OpShadow = MSV->getShadow(V);
|
|
Value *OpOrigin = MSV->MS.TrackOrigins ? MSV->getOrigin(V) : 0;
|
|
return Add(OpShadow, OpOrigin);
|
|
}
|
|
|
|
/// \brief 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);
|
|
}
|
|
}
|
|
};
|
|
|
|
typedef Combiner<true> ShadowAndOriginCombiner;
|
|
typedef Combiner<false> OriginCombiner;
|
|
|
|
/// \brief 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() ?
|
|
Ty->getVectorNumElements() * Ty->getScalarSizeInBits() :
|
|
Ty->getPrimitiveSizeInBits();
|
|
}
|
|
|
|
/// \brief Cast between two shadow types, extending or truncating as
|
|
/// necessary.
|
|
Value *CreateShadowCast(IRBuilder<> &IRB, Value *V, Type *dstTy) {
|
|
Type *srcTy = V->getType();
|
|
if (dstTy->isIntegerTy() && srcTy->isIntegerTy())
|
|
return IRB.CreateIntCast(V, dstTy, false);
|
|
if (dstTy->isVectorTy() && srcTy->isVectorTy() &&
|
|
dstTy->getVectorNumElements() == srcTy->getVectorNumElements())
|
|
return IRB.CreateIntCast(V, dstTy, false);
|
|
size_t srcSizeInBits = VectorOrPrimitiveTypeSizeInBits(srcTy);
|
|
size_t dstSizeInBits = VectorOrPrimitiveTypeSizeInBits(dstTy);
|
|
Value *V1 = IRB.CreateBitCast(V, Type::getIntNTy(*MS.C, srcSizeInBits));
|
|
Value *V2 =
|
|
IRB.CreateIntCast(V1, Type::getIntNTy(*MS.C, dstSizeInBits), false);
|
|
return IRB.CreateBitCast(V2, dstTy);
|
|
// TODO: handle struct types.
|
|
}
|
|
|
|
/// \brief 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 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 visitMul(BinaryOperator &I) { handleShadowOr(I); }
|
|
|
|
void handleDiv(Instruction &I) {
|
|
IRBuilder<> IRB(&I);
|
|
// Strict on the second argument.
|
|
insertCheck(I.getOperand(1), &I);
|
|
setShadow(&I, getShadow(&I, 0));
|
|
setOrigin(&I, getOrigin(&I, 0));
|
|
}
|
|
|
|
void visitUDiv(BinaryOperator &I) { handleDiv(I); }
|
|
void visitSDiv(BinaryOperator &I) { handleDiv(I); }
|
|
void visitFDiv(BinaryOperator &I) { handleDiv(I); }
|
|
void visitURem(BinaryOperator &I) { handleDiv(I); }
|
|
void visitSRem(BinaryOperator &I) { handleDiv(I); }
|
|
void visitFRem(BinaryOperator &I) { handleDiv(I); }
|
|
|
|
/// \brief Instrument == and != comparisons.
|
|
///
|
|
/// Sometimes the comparison result is known even if some of the bits of the
|
|
/// arguments are not.
|
|
void handleEqualityComparison(ICmpInst &I) {
|
|
IRBuilder<> IRB(&I);
|
|
Value *A = I.getOperand(0);
|
|
Value *B = I.getOperand(1);
|
|
Value *Sa = getShadow(A);
|
|
Value *Sb = getShadow(B);
|
|
|
|
// 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);
|
|
}
|
|
|
|
/// \brief 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));
|
|
}
|
|
}
|
|
|
|
/// \brief 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);
|
|
}
|
|
}
|
|
|
|
/// \brief 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);
|
|
}
|
|
|
|
/// \brief Instrument signed relational comparisons.
|
|
///
|
|
/// Handle (x<0) and (x>=0) comparisons (essentially, sign bit tests) by
|
|
/// propagating the highest bit of the shadow. Everything else is delegated
|
|
/// to handleShadowOr().
|
|
void handleSignedRelationalComparison(ICmpInst &I) {
|
|
Constant *constOp0 = dyn_cast<Constant>(I.getOperand(0));
|
|
Constant *constOp1 = dyn_cast<Constant>(I.getOperand(1));
|
|
Value* op = NULL;
|
|
CmpInst::Predicate pre = I.getPredicate();
|
|
if (constOp0 && constOp0->isNullValue() &&
|
|
(pre == CmpInst::ICMP_SGT || pre == CmpInst::ICMP_SLE)) {
|
|
op = I.getOperand(1);
|
|
} else if (constOp1 && constOp1->isNullValue() &&
|
|
(pre == CmpInst::ICMP_SLT || pre == CmpInst::ICMP_SGE)) {
|
|
op = I.getOperand(0);
|
|
}
|
|
if (op) {
|
|
IRBuilder<> IRB(&I);
|
|
Value* Shadow =
|
|
IRB.CreateICmpSLT(getShadow(op), getCleanShadow(op), "_msprop_icmpslt");
|
|
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); }
|
|
|
|
/// \brief Instrument llvm.memmove
|
|
///
|
|
/// At this point we don't know if llvm.memmove will be inlined or not.
|
|
/// If we don't instrument it and it gets inlined,
|
|
/// our interceptor will not kick in and we will lose the memmove.
|
|
/// If we instrument the call here, but it does not get inlined,
|
|
/// we will memove the shadow twice: which is bad in case
|
|
/// of overlapping regions. So, we simply lower the intrinsic to a call.
|
|
///
|
|
/// Similar situation exists for memcpy and memset.
|
|
void visitMemMoveInst(MemMoveInst &I) {
|
|
IRBuilder<> IRB(&I);
|
|
IRB.CreateCall3(
|
|
MS.MemmoveFn,
|
|
IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
|
|
IRB.CreatePointerCast(I.getArgOperand(1), IRB.getInt8PtrTy()),
|
|
IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false));
|
|
I.eraseFromParent();
|
|
}
|
|
|
|
// 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.CreateCall3(
|
|
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.CreateCall3(
|
|
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);
|
|
}
|
|
|
|
enum IntrinsicKind {
|
|
IK_DoesNotAccessMemory,
|
|
IK_OnlyReadsMemory,
|
|
IK_WritesMemory
|
|
};
|
|
|
|
static IntrinsicKind getIntrinsicKind(Intrinsic::ID iid) {
|
|
const int DoesNotAccessMemory = IK_DoesNotAccessMemory;
|
|
const int OnlyReadsArgumentPointees = IK_OnlyReadsMemory;
|
|
const int OnlyReadsMemory = IK_OnlyReadsMemory;
|
|
const int OnlyAccessesArgumentPointees = IK_WritesMemory;
|
|
const int UnknownModRefBehavior = IK_WritesMemory;
|
|
#define GET_INTRINSIC_MODREF_BEHAVIOR
|
|
#define ModRefBehavior IntrinsicKind
|
|
#include "llvm/IR/Intrinsics.gen"
|
|
#undef ModRefBehavior
|
|
#undef GET_INTRINSIC_MODREF_BEHAVIOR
|
|
}
|
|
|
|
/// \brief 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 = getShadowPtr(Addr, Shadow->getType(), IRB);
|
|
|
|
// We don't know the pointer alignment (could be unaligned SSE store!).
|
|
// Have to assume to worst case.
|
|
IRB.CreateAlignedStore(Shadow, ShadowPtr, 1);
|
|
|
|
if (ClCheckAccessAddress)
|
|
insertCheck(Addr, &I);
|
|
|
|
// FIXME: use ClStoreCleanOrigin
|
|
// FIXME: factor out common code from materializeStores
|
|
if (MS.TrackOrigins)
|
|
IRB.CreateStore(getOrigin(&I, 1), getOriginPtr(Addr, IRB));
|
|
return true;
|
|
}
|
|
|
|
/// \brief 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 = getShadowPtr(Addr, ShadowTy, IRB);
|
|
// We don't know the pointer alignment (could be unaligned SSE load!).
|
|
// Have to assume to worst case.
|
|
setShadow(&I, IRB.CreateAlignedLoad(ShadowPtr, 1, "_msld"));
|
|
|
|
if (ClCheckAccessAddress)
|
|
insertCheck(Addr, &I);
|
|
|
|
if (MS.TrackOrigins)
|
|
setOrigin(&I, IRB.CreateLoad(getOriginPtr(Addr, IRB)));
|
|
return true;
|
|
}
|
|
|
|
/// \brief 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;
|
|
}
|
|
|
|
/// \brief 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 intrumentation 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;
|
|
|
|
Intrinsic::ID iid = I.getIntrinsicID();
|
|
IntrinsicKind IK = getIntrinsicKind(iid);
|
|
bool OnlyReadsMemory = IK == IK_OnlyReadsMemory;
|
|
bool WritesMemory = IK == IK_WritesMemory;
|
|
assert(!(OnlyReadsMemory && WritesMemory));
|
|
|
|
if (NumArgOperands == 2 &&
|
|
I.getArgOperand(0)->getType()->isPointerTy() &&
|
|
I.getArgOperand(1)->getType()->isVectorTy() &&
|
|
I.getType()->isVoidTy() &&
|
|
WritesMemory) {
|
|
// This looks like a vector store.
|
|
return handleVectorStoreIntrinsic(I);
|
|
}
|
|
|
|
if (NumArgOperands == 1 &&
|
|
I.getArgOperand(0)->getType()->isPointerTy() &&
|
|
I.getType()->isVectorTy() &&
|
|
OnlyReadsMemory) {
|
|
// This looks like a vector load.
|
|
return handleVectorLoadIntrinsic(I);
|
|
}
|
|
|
|
if (!OnlyReadsMemory && !WritesMemory)
|
|
if (maybeHandleSimpleNomemIntrinsic(I))
|
|
return true;
|
|
|
|
// FIXME: detect and handle SSE maskstore/maskload
|
|
return false;
|
|
}
|
|
|
|
void handleBswap(IntrinsicInst &I) {
|
|
IRBuilder<> IRB(&I);
|
|
Value *Op = I.getArgOperand(0);
|
|
Type *OpType = Op->getType();
|
|
Function *BswapFunc = Intrinsic::getDeclaration(
|
|
F.getParent(), Intrinsic::bswap, ArrayRef<Type*>(&OpType, 1));
|
|
setShadow(&I, IRB.CreateCall(BswapFunc, getShadow(Op)));
|
|
setOrigin(&I, getOrigin(Op));
|
|
}
|
|
|
|
void visitIntrinsicInst(IntrinsicInst &I) {
|
|
switch (I.getIntrinsicID()) {
|
|
case llvm::Intrinsic::bswap:
|
|
handleBswap(I);
|
|
break;
|
|
default:
|
|
if (!handleUnknownIntrinsic(I))
|
|
visitInstruction(I);
|
|
break;
|
|
}
|
|
}
|
|
|
|
void visitCallSite(CallSite CS) {
|
|
Instruction &I = *CS.getInstruction();
|
|
assert((CS.isCall() || CS.isInvoke()) && "Unknown type of CallSite");
|
|
if (CS.isCall()) {
|
|
CallInst *Call = cast<CallInst>(&I);
|
|
|
|
// For inline asm, 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 (Call->isInlineAsm()) {
|
|
visitInstruction(I);
|
|
return;
|
|
}
|
|
|
|
// Allow only tail calls with the same types, otherwise
|
|
// we may have a false positive: shadow for a non-void RetVal
|
|
// will get propagated to a void RetVal.
|
|
if (Call->isTailCall() && Call->getType() != Call->getParent()->getType())
|
|
Call->setTailCall(false);
|
|
|
|
assert(!isa<IntrinsicInst>(&I) && "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);
|
|
Func->removeAttributes(AttributeSet::FunctionIndex,
|
|
AttributeSet::get(Func->getContext(),
|
|
AttributeSet::FunctionIndex,
|
|
B));
|
|
}
|
|
}
|
|
IRBuilder<> IRB(&I);
|
|
unsigned ArgOffset = 0;
|
|
DEBUG(dbgs() << " CallSite: " << I << "\n");
|
|
for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end();
|
|
ArgIt != End; ++ArgIt) {
|
|
Value *A = *ArgIt;
|
|
unsigned i = ArgIt - CS.arg_begin();
|
|
if (!A->getType()->isSized()) {
|
|
DEBUG(dbgs() << "Arg " << i << " is not sized: " << I << "\n");
|
|
continue;
|
|
}
|
|
unsigned Size = 0;
|
|
Value *Store = 0;
|
|
// Compute the Shadow for arg even if it is ByVal, because
|
|
// in that case getShadow() will copy the actual arg shadow to
|
|
// __msan_param_tls.
|
|
Value *ArgShadow = getShadow(A);
|
|
Value *ArgShadowBase = getShadowPtrForArgument(A, IRB, ArgOffset);
|
|
DEBUG(dbgs() << " Arg#" << i << ": " << *A <<
|
|
" Shadow: " << *ArgShadow << "\n");
|
|
if (CS.paramHasAttr(i + 1, Attribute::ByVal)) {
|
|
assert(A->getType()->isPointerTy() &&
|
|
"ByVal argument is not a pointer!");
|
|
Size = MS.TD->getTypeAllocSize(A->getType()->getPointerElementType());
|
|
unsigned Alignment = CS.getParamAlignment(i + 1);
|
|
Store = IRB.CreateMemCpy(ArgShadowBase,
|
|
getShadowPtr(A, Type::getInt8Ty(*MS.C), IRB),
|
|
Size, Alignment);
|
|
} else {
|
|
Size = MS.TD->getTypeAllocSize(A->getType());
|
|
Store = IRB.CreateAlignedStore(ArgShadow, ArgShadowBase,
|
|
kShadowTLSAlignment);
|
|
}
|
|
if (MS.TrackOrigins)
|
|
IRB.CreateStore(getOrigin(A),
|
|
getOriginPtrForArgument(A, IRB, ArgOffset));
|
|
(void)Store;
|
|
assert(Size != 0 && Store != 0);
|
|
DEBUG(dbgs() << " Param:" << *Store << "\n");
|
|
ArgOffset += DataLayout::RoundUpAlignment(Size, 8);
|
|
}
|
|
DEBUG(dbgs() << " done with call args\n");
|
|
|
|
FunctionType *FT =
|
|
cast<FunctionType>(CS.getCalledValue()->getType()-> getContainedType(0));
|
|
if (FT->isVarArg()) {
|
|
VAHelper->visitCallSite(CS, IRB);
|
|
}
|
|
|
|
// Now, get the shadow for the RetVal.
|
|
if (!I.getType()->isSized()) return;
|
|
IRBuilder<> IRBBefore(&I);
|
|
// Untill we have full dynamic coverage, make sure the retval shadow is 0.
|
|
Value *Base = getShadowPtrForRetval(&I, IRBBefore);
|
|
IRBBefore.CreateAlignedStore(getCleanShadow(&I), Base, kShadowTLSAlignment);
|
|
Instruction *NextInsn = 0;
|
|
if (CS.isCall()) {
|
|
NextInsn = I.getNextNode();
|
|
} else {
|
|
BasicBlock *NormalDest = cast<InvokeInst>(&I)->getNormalDest();
|
|
if (!NormalDest->getSinglePredecessor()) {
|
|
// FIXME: this case is tricky, so we are just conservative here.
|
|
// Perhaps we need to split the edge between this BB and NormalDest,
|
|
// but a naive attempt to use SplitEdge leads to a crash.
|
|
setShadow(&I, getCleanShadow(&I));
|
|
setOrigin(&I, getCleanOrigin());
|
|
return;
|
|
}
|
|
NextInsn = NormalDest->getFirstInsertionPt();
|
|
assert(NextInsn &&
|
|
"Could not find insertion point for retval shadow load");
|
|
}
|
|
IRBuilder<> IRBAfter(NextInsn);
|
|
Value *RetvalShadow =
|
|
IRBAfter.CreateAlignedLoad(getShadowPtrForRetval(&I, IRBAfter),
|
|
kShadowTLSAlignment, "_msret");
|
|
setShadow(&I, RetvalShadow);
|
|
if (MS.TrackOrigins)
|
|
setOrigin(&I, IRBAfter.CreateLoad(getOriginPtrForRetval(IRBAfter)));
|
|
}
|
|
|
|
void visitReturnInst(ReturnInst &I) {
|
|
IRBuilder<> IRB(&I);
|
|
if (Value *RetVal = I.getReturnValue()) {
|
|
// Set the shadow for the RetVal.
|
|
Value *Shadow = getShadow(RetVal);
|
|
Value *ShadowPtr = getShadowPtrForRetval(RetVal, IRB);
|
|
DEBUG(dbgs() << "Return: " << *Shadow << "\n" << *ShadowPtr << "\n");
|
|
IRB.CreateAlignedStore(Shadow, ShadowPtr, kShadowTLSAlignment);
|
|
if (MS.TrackOrigins)
|
|
IRB.CreateStore(getOrigin(RetVal), getOriginPtrForRetval(IRB));
|
|
}
|
|
}
|
|
|
|
void visitPHINode(PHINode &I) {
|
|
IRBuilder<> IRB(&I);
|
|
ShadowPHINodes.push_back(&I);
|
|
setShadow(&I, IRB.CreatePHI(getShadowTy(&I), I.getNumIncomingValues(),
|
|
"_msphi_s"));
|
|
if (MS.TrackOrigins)
|
|
setOrigin(&I, IRB.CreatePHI(MS.OriginTy, I.getNumIncomingValues(),
|
|
"_msphi_o"));
|
|
}
|
|
|
|
void visitAllocaInst(AllocaInst &I) {
|
|
setShadow(&I, getCleanShadow(&I));
|
|
if (!ClPoisonStack) return;
|
|
IRBuilder<> IRB(I.getNextNode());
|
|
uint64_t Size = MS.TD->getTypeAllocSize(I.getAllocatedType());
|
|
if (ClPoisonStackWithCall) {
|
|
IRB.CreateCall2(MS.MsanPoisonStackFn,
|
|
IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()),
|
|
ConstantInt::get(MS.IntptrTy, Size));
|
|
} else {
|
|
Value *ShadowBase = getShadowPtr(&I, Type::getInt8PtrTy(*MS.C), IRB);
|
|
IRB.CreateMemSet(ShadowBase, IRB.getInt8(ClPoisonStackPattern),
|
|
Size, I.getAlignment());
|
|
}
|
|
|
|
if (MS.TrackOrigins) {
|
|
setOrigin(&I, getCleanOrigin());
|
|
SmallString<2048> StackDescriptionStorage;
|
|
raw_svector_ostream StackDescription(StackDescriptionStorage);
|
|
// We create a string with a description of the stack allocation and
|
|
// pass it into __msan_set_alloca_origin.
|
|
// It will be printed by the run-time if stack-originated UMR is found.
|
|
// The first 4 bytes of the string are set to '----' and will be replaced
|
|
// by __msan_va_arg_overflow_size_tls at the first call.
|
|
StackDescription << "----" << I.getName() << "@" << F.getName();
|
|
Value *Descr =
|
|
createPrivateNonConstGlobalForString(*F.getParent(),
|
|
StackDescription.str());
|
|
IRB.CreateCall3(MS.MsanSetAllocaOriginFn,
|
|
IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()),
|
|
ConstantInt::get(MS.IntptrTy, Size),
|
|
IRB.CreatePointerCast(Descr, IRB.getInt8PtrTy()));
|
|
}
|
|
}
|
|
|
|
void visitSelectInst(SelectInst& I) {
|
|
IRBuilder<> IRB(&I);
|
|
setShadow(&I, IRB.CreateSelect(I.getCondition(),
|
|
getShadow(I.getTrueValue()), getShadow(I.getFalseValue()),
|
|
"_msprop"));
|
|
if (MS.TrackOrigins) {
|
|
// Origins are always i32, so any vector conditions must be flattened.
|
|
// FIXME: consider tracking vector origins for app vectors?
|
|
Value *Cond = I.getCondition();
|
|
if (Cond->getType()->isVectorTy()) {
|
|
Value *ConvertedShadow = convertToShadowTyNoVec(Cond, IRB);
|
|
Cond = IRB.CreateICmpNE(ConvertedShadow,
|
|
getCleanShadow(ConvertedShadow), "_mso_select");
|
|
}
|
|
setOrigin(&I, IRB.CreateSelect(Cond,
|
|
getOrigin(I.getTrueValue()), getOrigin(I.getFalseValue())));
|
|
}
|
|
}
|
|
|
|
void visitLandingPadInst(LandingPadInst &I) {
|
|
// Do nothing.
|
|
// See http://code.google.com/p/memory-sanitizer/issues/detail?id=1
|
|
setShadow(&I, getCleanShadow(&I));
|
|
setOrigin(&I, getCleanOrigin());
|
|
}
|
|
|
|
void visitGetElementPtrInst(GetElementPtrInst &I) {
|
|
handleShadowOr(I);
|
|
}
|
|
|
|
void visitExtractValueInst(ExtractValueInst &I) {
|
|
IRBuilder<> IRB(&I);
|
|
Value *Agg = I.getAggregateOperand();
|
|
DEBUG(dbgs() << "ExtractValue: " << I << "\n");
|
|
Value *AggShadow = getShadow(Agg);
|
|
DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n");
|
|
Value *ResShadow = IRB.CreateExtractValue(AggShadow, I.getIndices());
|
|
DEBUG(dbgs() << " ResShadow: " << *ResShadow << "\n");
|
|
setShadow(&I, ResShadow);
|
|
setOrigin(&I, getCleanOrigin());
|
|
}
|
|
|
|
void visitInsertValueInst(InsertValueInst &I) {
|
|
IRBuilder<> IRB(&I);
|
|
DEBUG(dbgs() << "InsertValue: " << I << "\n");
|
|
Value *AggShadow = getShadow(I.getAggregateOperand());
|
|
Value *InsShadow = getShadow(I.getInsertedValueOperand());
|
|
DEBUG(dbgs() << " AggShadow: " << *AggShadow << "\n");
|
|
DEBUG(dbgs() << " InsShadow: " << *InsShadow << "\n");
|
|
Value *Res = IRB.CreateInsertValue(AggShadow, InsShadow, I.getIndices());
|
|
DEBUG(dbgs() << " Res: " << *Res << "\n");
|
|
setShadow(&I, Res);
|
|
setOrigin(&I, getCleanOrigin());
|
|
}
|
|
|
|
void dumpInst(Instruction &I) {
|
|
if (CallInst *CI = dyn_cast<CallInst>(&I)) {
|
|
errs() << "ZZZ call " << CI->getCalledFunction()->getName() << "\n";
|
|
} else {
|
|
errs() << "ZZZ " << I.getOpcodeName() << "\n";
|
|
}
|
|
errs() << "QQQ " << I << "\n";
|
|
}
|
|
|
|
void visitResumeInst(ResumeInst &I) {
|
|
DEBUG(dbgs() << "Resume: " << I << "\n");
|
|
// Nothing to do here.
|
|
}
|
|
|
|
void visitInstruction(Instruction &I) {
|
|
// Everything else: stop propagating and check for poisoned shadow.
|
|
if (ClDumpStrictInstructions)
|
|
dumpInst(I);
|
|
DEBUG(dbgs() << "DEFAULT: " << I << "\n");
|
|
for (size_t i = 0, n = I.getNumOperands(); i < n; i++)
|
|
insertCheck(I.getOperand(i), &I);
|
|
setShadow(&I, getCleanShadow(&I));
|
|
setOrigin(&I, getCleanOrigin());
|
|
}
|
|
};
|
|
|
|
/// \brief AMD64-specific implementation of VarArgHelper.
|
|
struct VarArgAMD64Helper : public VarArgHelper {
|
|
// An unfortunate workaround for asymmetric lowering of va_arg stuff.
|
|
// See a comment in visitCallSite for more details.
|
|
static const unsigned AMD64GpEndOffset = 48; // AMD64 ABI Draft 0.99.6 p3.5.7
|
|
static const unsigned AMD64FpEndOffset = 176;
|
|
|
|
Function &F;
|
|
MemorySanitizer &MS;
|
|
MemorySanitizerVisitor &MSV;
|
|
Value *VAArgTLSCopy;
|
|
Value *VAArgOverflowSize;
|
|
|
|
SmallVector<CallInst*, 16> VAStartInstrumentationList;
|
|
|
|
VarArgAMD64Helper(Function &F, MemorySanitizer &MS,
|
|
MemorySanitizerVisitor &MSV)
|
|
: F(F), MS(MS), MSV(MSV), VAArgTLSCopy(0), VAArgOverflowSize(0) { }
|
|
|
|
enum ArgKind { AK_GeneralPurpose, AK_FloatingPoint, AK_Memory };
|
|
|
|
ArgKind classifyArgument(Value* arg) {
|
|
// A very rough approximation of X86_64 argument classification rules.
|
|
Type *T = arg->getType();
|
|
if (T->isFPOrFPVectorTy() || T->isX86_MMXTy())
|
|
return AK_FloatingPoint;
|
|
if (T->isIntegerTy() && T->getPrimitiveSizeInBits() <= 64)
|
|
return AK_GeneralPurpose;
|
|
if (T->isPointerTy())
|
|
return AK_GeneralPurpose;
|
|
return AK_Memory;
|
|
}
|
|
|
|
// For VarArg functions, store the argument shadow in an ABI-specific format
|
|
// that corresponds to va_list layout.
|
|
// We do this because Clang lowers va_arg in the frontend, and this pass
|
|
// only sees the low level code that deals with va_list internals.
|
|
// A much easier alternative (provided that Clang emits va_arg instructions)
|
|
// would have been to associate each live instance of va_list with a copy of
|
|
// MSanParamTLS, and extract shadow on va_arg() call in the argument list
|
|
// order.
|
|
void visitCallSite(CallSite &CS, IRBuilder<> &IRB) {
|
|
unsigned GpOffset = 0;
|
|
unsigned FpOffset = AMD64GpEndOffset;
|
|
unsigned OverflowOffset = AMD64FpEndOffset;
|
|
for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end();
|
|
ArgIt != End; ++ArgIt) {
|
|
Value *A = *ArgIt;
|
|
ArgKind AK = classifyArgument(A);
|
|
if (AK == AK_GeneralPurpose && GpOffset >= AMD64GpEndOffset)
|
|
AK = AK_Memory;
|
|
if (AK == AK_FloatingPoint && FpOffset >= AMD64FpEndOffset)
|
|
AK = AK_Memory;
|
|
Value *Base;
|
|
switch (AK) {
|
|
case AK_GeneralPurpose:
|
|
Base = getShadowPtrForVAArgument(A, IRB, GpOffset);
|
|
GpOffset += 8;
|
|
break;
|
|
case AK_FloatingPoint:
|
|
Base = getShadowPtrForVAArgument(A, IRB, FpOffset);
|
|
FpOffset += 16;
|
|
break;
|
|
case AK_Memory:
|
|
uint64_t ArgSize = MS.TD->getTypeAllocSize(A->getType());
|
|
Base = getShadowPtrForVAArgument(A, IRB, OverflowOffset);
|
|
OverflowOffset += DataLayout::RoundUpAlignment(ArgSize, 8);
|
|
}
|
|
IRB.CreateAlignedStore(MSV.getShadow(A), Base, kShadowTLSAlignment);
|
|
}
|
|
Constant *OverflowSize =
|
|
ConstantInt::get(IRB.getInt64Ty(), OverflowOffset - AMD64FpEndOffset);
|
|
IRB.CreateStore(OverflowSize, MS.VAArgOverflowSizeTLS);
|
|
}
|
|
|
|
/// \brief Compute the shadow address for a given va_arg.
|
|
Value *getShadowPtrForVAArgument(Value *A, IRBuilder<> &IRB,
|
|
int ArgOffset) {
|
|
Value *Base = IRB.CreatePointerCast(MS.VAArgTLS, MS.IntptrTy);
|
|
Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
|
|
return IRB.CreateIntToPtr(Base, PointerType::get(MSV.getShadowTy(A), 0),
|
|
"_msarg");
|
|
}
|
|
|
|
void visitVAStartInst(VAStartInst &I) {
|
|
IRBuilder<> IRB(&I);
|
|
VAStartInstrumentationList.push_back(&I);
|
|
Value *VAListTag = I.getArgOperand(0);
|
|
Value *ShadowPtr = MSV.getShadowPtr(VAListTag, IRB.getInt8Ty(), IRB);
|
|
|
|
// Unpoison the whole __va_list_tag.
|
|
// FIXME: magic ABI constants.
|
|
IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
|
|
/* size */24, /* alignment */8, false);
|
|
}
|
|
|
|
void visitVACopyInst(VACopyInst &I) {
|
|
IRBuilder<> IRB(&I);
|
|
Value *VAListTag = I.getArgOperand(0);
|
|
Value *ShadowPtr = MSV.getShadowPtr(VAListTag, IRB.getInt8Ty(), IRB);
|
|
|
|
// Unpoison the whole __va_list_tag.
|
|
// FIXME: magic ABI constants.
|
|
IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
|
|
/* size */24, /* alignment */8, false);
|
|
}
|
|
|
|
void finalizeInstrumentation() {
|
|
assert(!VAArgOverflowSize && !VAArgTLSCopy &&
|
|
"finalizeInstrumentation called twice");
|
|
if (!VAStartInstrumentationList.empty()) {
|
|
// If there is a va_start in this function, make a backup copy of
|
|
// va_arg_tls somewhere in the function entry block.
|
|
IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
|
|
VAArgOverflowSize = IRB.CreateLoad(MS.VAArgOverflowSizeTLS);
|
|
Value *CopySize =
|
|
IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, AMD64FpEndOffset),
|
|
VAArgOverflowSize);
|
|
VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
|
|
IRB.CreateMemCpy(VAArgTLSCopy, MS.VAArgTLS, CopySize, 8);
|
|
}
|
|
|
|
// Instrument va_start.
|
|
// Copy va_list shadow from the backup copy of the TLS contents.
|
|
for (size_t i = 0, n = VAStartInstrumentationList.size(); i < n; i++) {
|
|
CallInst *OrigInst = VAStartInstrumentationList[i];
|
|
IRBuilder<> IRB(OrigInst->getNextNode());
|
|
Value *VAListTag = OrigInst->getArgOperand(0);
|
|
|
|
Value *RegSaveAreaPtrPtr =
|
|
IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
|
|
ConstantInt::get(MS.IntptrTy, 16)),
|
|
Type::getInt64PtrTy(*MS.C));
|
|
Value *RegSaveAreaPtr = IRB.CreateLoad(RegSaveAreaPtrPtr);
|
|
Value *RegSaveAreaShadowPtr =
|
|
MSV.getShadowPtr(RegSaveAreaPtr, IRB.getInt8Ty(), IRB);
|
|
IRB.CreateMemCpy(RegSaveAreaShadowPtr, VAArgTLSCopy,
|
|
AMD64FpEndOffset, 16);
|
|
|
|
Value *OverflowArgAreaPtrPtr =
|
|
IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
|
|
ConstantInt::get(MS.IntptrTy, 8)),
|
|
Type::getInt64PtrTy(*MS.C));
|
|
Value *OverflowArgAreaPtr = IRB.CreateLoad(OverflowArgAreaPtrPtr);
|
|
Value *OverflowArgAreaShadowPtr =
|
|
MSV.getShadowPtr(OverflowArgAreaPtr, IRB.getInt8Ty(), IRB);
|
|
Value *SrcPtr =
|
|
getShadowPtrForVAArgument(VAArgTLSCopy, IRB, AMD64FpEndOffset);
|
|
IRB.CreateMemCpy(OverflowArgAreaShadowPtr, SrcPtr, VAArgOverflowSize, 16);
|
|
}
|
|
}
|
|
};
|
|
|
|
VarArgHelper* CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
|
|
MemorySanitizerVisitor &Visitor) {
|
|
return new VarArgAMD64Helper(Func, Msan, Visitor);
|
|
}
|
|
|
|
} // namespace
|
|
|
|
bool MemorySanitizer::runOnFunction(Function &F) {
|
|
MemorySanitizerVisitor Visitor(F, *this);
|
|
|
|
// Clear out readonly/readnone attributes.
|
|
AttrBuilder B;
|
|
B.addAttribute(Attribute::ReadOnly)
|
|
.addAttribute(Attribute::ReadNone);
|
|
F.removeAttributes(AttributeSet::FunctionIndex,
|
|
AttributeSet::get(F.getContext(),
|
|
AttributeSet::FunctionIndex, B));
|
|
|
|
return Visitor.runOnFunction();
|
|
}
|