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

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//===-- DataFlowSanitizer.cpp - dynamic data flow analysis ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
/// This file is a part of DataFlowSanitizer, a generalised dynamic data flow
/// analysis.
///
/// Unlike other Sanitizer tools, this tool is not designed to detect a specific
/// class of bugs on its own. Instead, it provides a generic dynamic data flow
/// analysis framework to be used by clients to help detect application-specific
/// issues within their own code.
///
/// The analysis is based on automatic propagation of data flow labels (also
/// known as taint labels) through a program as it performs computation. Each
/// byte of application memory is backed by two bytes of shadow memory which
/// hold the label. On Linux/x86_64, memory is laid out as follows:
///
/// +--------------------+ 0x800000000000 (top of memory)
/// | application memory |
/// +--------------------+ 0x700000008000 (kAppAddr)
/// | |
/// | unused |
/// | |
/// +--------------------+ 0x200200000000 (kUnusedAddr)
/// | union table |
/// +--------------------+ 0x200000000000 (kUnionTableAddr)
/// | shadow memory |
/// +--------------------+ 0x000000010000 (kShadowAddr)
/// | reserved by kernel |
/// +--------------------+ 0x000000000000
///
/// To derive a shadow memory address from an application memory address,
/// bits 44-46 are cleared to bring the address into the range
/// [0x000000008000,0x100000000000). Then the address is shifted left by 1 to
/// account for the double byte representation of shadow labels and move the
/// address into the shadow memory range. See the function
/// DataFlowSanitizer::getShadowAddress below.
///
/// For more information, please refer to the design document:
/// http://clang.llvm.org/docs/DataFlowSanitizerDesign.html
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/InstVisitor.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/SpecialCaseList.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include <algorithm>
#include <iterator>
#include <set>
#include <utility>
using namespace llvm;
// External symbol to be used when generating the shadow address for
// architectures with multiple VMAs. Instead of using a constant integer
// the runtime will set the external mask based on the VMA range.
static const char *const kDFSanExternShadowPtrMask = "__dfsan_shadow_ptr_mask";
// The -dfsan-preserve-alignment flag controls whether this pass assumes that
// alignment requirements provided by the input IR are correct. For example,
// if the input IR contains a load with alignment 8, this flag will cause
// the shadow load to have alignment 16. This flag is disabled by default as
// we have unfortunately encountered too much code (including Clang itself;
// see PR14291) which performs misaligned access.
static cl::opt<bool> ClPreserveAlignment(
"dfsan-preserve-alignment",
cl::desc("respect alignment requirements provided by input IR"), cl::Hidden,
cl::init(false));
// The ABI list files control how shadow parameters are passed. The pass treats
// every function labelled "uninstrumented" in the ABI list file as conforming
// to the "native" (i.e. unsanitized) ABI. Unless the ABI list contains
// additional annotations for those functions, a call to one of those functions
// will produce a warning message, as the labelling behaviour of the function is
// unknown. The other supported annotations are "functional" and "discard",
// which are described below under DataFlowSanitizer::WrapperKind.
static cl::list<std::string> ClABIListFiles(
"dfsan-abilist",
cl::desc("File listing native ABI functions and how the pass treats them"),
cl::Hidden);
// Controls whether the pass uses IA_Args or IA_TLS as the ABI for instrumented
// functions (see DataFlowSanitizer::InstrumentedABI below).
static cl::opt<bool> ClArgsABI(
"dfsan-args-abi",
cl::desc("Use the argument ABI rather than the TLS ABI"),
cl::Hidden);
// Controls whether the pass includes or ignores the labels of pointers in load
// instructions.
static cl::opt<bool> ClCombinePointerLabelsOnLoad(
"dfsan-combine-pointer-labels-on-load",
cl::desc("Combine the label of the pointer with the label of the data when "
"loading from memory."),
cl::Hidden, cl::init(true));
// Controls whether the pass includes or ignores the labels of pointers in
// stores instructions.
static cl::opt<bool> ClCombinePointerLabelsOnStore(
"dfsan-combine-pointer-labels-on-store",
cl::desc("Combine the label of the pointer with the label of the data when "
"storing in memory."),
cl::Hidden, cl::init(false));
static cl::opt<bool> ClDebugNonzeroLabels(
"dfsan-debug-nonzero-labels",
cl::desc("Insert calls to __dfsan_nonzero_label on observing a parameter, "
"load or return with a nonzero label"),
cl::Hidden);
namespace {
StringRef GetGlobalTypeString(const GlobalValue &G) {
// Types of GlobalVariables are always pointer types.
Type *GType = G.getValueType();
// For now we support blacklisting struct types only.
if (StructType *SGType = dyn_cast<StructType>(GType)) {
if (!SGType->isLiteral())
return SGType->getName();
}
return "<unknown type>";
}
class DFSanABIList {
std::unique_ptr<SpecialCaseList> SCL;
public:
DFSanABIList() {}
void set(std::unique_ptr<SpecialCaseList> List) { SCL = std::move(List); }
/// Returns whether either this function or its source file are listed in the
/// given category.
bool isIn(const Function &F, StringRef Category) const {
return isIn(*F.getParent(), Category) ||
SCL->inSection("fun", F.getName(), Category);
}
/// Returns whether this global alias is listed in the given category.
///
/// If GA aliases a function, the alias's name is matched as a function name
/// would be. Similarly, aliases of globals are matched like globals.
bool isIn(const GlobalAlias &GA, StringRef Category) const {
if (isIn(*GA.getParent(), Category))
return true;
if (isa<FunctionType>(GA.getValueType()))
return SCL->inSection("fun", GA.getName(), Category);
return SCL->inSection("global", GA.getName(), Category) ||
SCL->inSection("type", GetGlobalTypeString(GA), Category);
}
/// Returns whether this module is listed in the given category.
bool isIn(const Module &M, StringRef Category) const {
return SCL->inSection("src", M.getModuleIdentifier(), Category);
}
};
class DataFlowSanitizer : public ModulePass {
friend struct DFSanFunction;
friend class DFSanVisitor;
enum {
ShadowWidth = 16
};
/// Which ABI should be used for instrumented functions?
enum InstrumentedABI {
/// Argument and return value labels are passed through additional
/// arguments and by modifying the return type.
IA_Args,
/// Argument and return value labels are passed through TLS variables
/// __dfsan_arg_tls and __dfsan_retval_tls.
IA_TLS
};
/// How should calls to uninstrumented functions be handled?
enum WrapperKind {
/// This function is present in an uninstrumented form but we don't know
/// how it should be handled. Print a warning and call the function anyway.
/// Don't label the return value.
WK_Warning,
/// This function does not write to (user-accessible) memory, and its return
/// value is unlabelled.
WK_Discard,
/// This function does not write to (user-accessible) memory, and the label
/// of its return value is the union of the label of its arguments.
WK_Functional,
/// Instead of calling the function, a custom wrapper __dfsw_F is called,
/// where F is the name of the function. This function may wrap the
/// original function or provide its own implementation. This is similar to
/// the IA_Args ABI, except that IA_Args uses a struct return type to
/// pass the return value shadow in a register, while WK_Custom uses an
/// extra pointer argument to return the shadow. This allows the wrapped
/// form of the function type to be expressed in C.
WK_Custom
};
Module *Mod;
LLVMContext *Ctx;
IntegerType *ShadowTy;
PointerType *ShadowPtrTy;
IntegerType *IntptrTy;
ConstantInt *ZeroShadow;
ConstantInt *ShadowPtrMask;
ConstantInt *ShadowPtrMul;
Constant *ArgTLS;
Constant *RetvalTLS;
void *(*GetArgTLSPtr)();
void *(*GetRetvalTLSPtr)();
Constant *GetArgTLS;
Constant *GetRetvalTLS;
Constant *ExternalShadowMask;
FunctionType *DFSanUnionFnTy;
FunctionType *DFSanUnionLoadFnTy;
FunctionType *DFSanUnimplementedFnTy;
FunctionType *DFSanSetLabelFnTy;
FunctionType *DFSanNonzeroLabelFnTy;
FunctionType *DFSanVarargWrapperFnTy;
Constant *DFSanUnionFn;
Constant *DFSanCheckedUnionFn;
Constant *DFSanUnionLoadFn;
Constant *DFSanUnimplementedFn;
Constant *DFSanSetLabelFn;
Constant *DFSanNonzeroLabelFn;
Constant *DFSanVarargWrapperFn;
MDNode *ColdCallWeights;
DFSanABIList ABIList;
DenseMap<Value *, Function *> UnwrappedFnMap;
AttributeList ReadOnlyNoneAttrs;
bool DFSanRuntimeShadowMask;
Value *getShadowAddress(Value *Addr, Instruction *Pos);
bool isInstrumented(const Function *F);
bool isInstrumented(const GlobalAlias *GA);
FunctionType *getArgsFunctionType(FunctionType *T);
FunctionType *getTrampolineFunctionType(FunctionType *T);
FunctionType *getCustomFunctionType(FunctionType *T);
InstrumentedABI getInstrumentedABI();
WrapperKind getWrapperKind(Function *F);
void addGlobalNamePrefix(GlobalValue *GV);
Function *buildWrapperFunction(Function *F, StringRef NewFName,
GlobalValue::LinkageTypes NewFLink,
FunctionType *NewFT);
Constant *getOrBuildTrampolineFunction(FunctionType *FT, StringRef FName);
public:
DataFlowSanitizer(
const std::vector<std::string> &ABIListFiles = std::vector<std::string>(),
void *(*getArgTLS)() = nullptr, void *(*getRetValTLS)() = nullptr);
static char ID;
bool doInitialization(Module &M) override;
bool runOnModule(Module &M) override;
};
struct DFSanFunction {
DataFlowSanitizer &DFS;
Function *F;
DominatorTree DT;
DataFlowSanitizer::InstrumentedABI IA;
bool IsNativeABI;
Value *ArgTLSPtr;
Value *RetvalTLSPtr;
AllocaInst *LabelReturnAlloca;
DenseMap<Value *, Value *> ValShadowMap;
DenseMap<AllocaInst *, AllocaInst *> AllocaShadowMap;
std::vector<std::pair<PHINode *, PHINode *> > PHIFixups;
DenseSet<Instruction *> SkipInsts;
std::vector<Value *> NonZeroChecks;
bool AvoidNewBlocks;
struct CachedCombinedShadow {
BasicBlock *Block;
Value *Shadow;
};
DenseMap<std::pair<Value *, Value *>, CachedCombinedShadow>
CachedCombinedShadows;
DenseMap<Value *, std::set<Value *>> ShadowElements;
DFSanFunction(DataFlowSanitizer &DFS, Function *F, bool IsNativeABI)
: DFS(DFS), F(F), IA(DFS.getInstrumentedABI()),
IsNativeABI(IsNativeABI), ArgTLSPtr(nullptr), RetvalTLSPtr(nullptr),
LabelReturnAlloca(nullptr) {
DT.recalculate(*F);
// FIXME: Need to track down the register allocator issue which causes poor
// performance in pathological cases with large numbers of basic blocks.
AvoidNewBlocks = F->size() > 1000;
}
Value *getArgTLSPtr();
Value *getArgTLS(unsigned Index, Instruction *Pos);
Value *getRetvalTLS();
Value *getShadow(Value *V);
void setShadow(Instruction *I, Value *Shadow);
Value *combineShadows(Value *V1, Value *V2, Instruction *Pos);
Value *combineOperandShadows(Instruction *Inst);
Value *loadShadow(Value *ShadowAddr, uint64_t Size, uint64_t Align,
Instruction *Pos);
void storeShadow(Value *Addr, uint64_t Size, uint64_t Align, Value *Shadow,
Instruction *Pos);
};
class DFSanVisitor : public InstVisitor<DFSanVisitor> {
public:
DFSanFunction &DFSF;
DFSanVisitor(DFSanFunction &DFSF) : DFSF(DFSF) {}
const DataLayout &getDataLayout() const {
return DFSF.F->getParent()->getDataLayout();
}
void visitOperandShadowInst(Instruction &I);
void visitBinaryOperator(BinaryOperator &BO);
void visitCastInst(CastInst &CI);
void visitCmpInst(CmpInst &CI);
void visitGetElementPtrInst(GetElementPtrInst &GEPI);
void visitLoadInst(LoadInst &LI);
void visitStoreInst(StoreInst &SI);
void visitReturnInst(ReturnInst &RI);
void visitCallSite(CallSite CS);
void visitPHINode(PHINode &PN);
void visitExtractElementInst(ExtractElementInst &I);
void visitInsertElementInst(InsertElementInst &I);
void visitShuffleVectorInst(ShuffleVectorInst &I);
void visitExtractValueInst(ExtractValueInst &I);
void visitInsertValueInst(InsertValueInst &I);
void visitAllocaInst(AllocaInst &I);
void visitSelectInst(SelectInst &I);
void visitMemSetInst(MemSetInst &I);
void visitMemTransferInst(MemTransferInst &I);
};
}
char DataFlowSanitizer::ID;
INITIALIZE_PASS(DataFlowSanitizer, "dfsan",
"DataFlowSanitizer: dynamic data flow analysis.", false, false)
ModulePass *
llvm::createDataFlowSanitizerPass(const std::vector<std::string> &ABIListFiles,
void *(*getArgTLS)(),
void *(*getRetValTLS)()) {
return new DataFlowSanitizer(ABIListFiles, getArgTLS, getRetValTLS);
}
DataFlowSanitizer::DataFlowSanitizer(
const std::vector<std::string> &ABIListFiles, void *(*getArgTLS)(),
void *(*getRetValTLS)())
: ModulePass(ID), GetArgTLSPtr(getArgTLS), GetRetvalTLSPtr(getRetValTLS),
DFSanRuntimeShadowMask(false) {
std::vector<std::string> AllABIListFiles(std::move(ABIListFiles));
AllABIListFiles.insert(AllABIListFiles.end(), ClABIListFiles.begin(),
ClABIListFiles.end());
ABIList.set(SpecialCaseList::createOrDie(AllABIListFiles));
}
FunctionType *DataFlowSanitizer::getArgsFunctionType(FunctionType *T) {
llvm::SmallVector<Type *, 4> ArgTypes(T->param_begin(), T->param_end());
ArgTypes.append(T->getNumParams(), ShadowTy);
if (T->isVarArg())
ArgTypes.push_back(ShadowPtrTy);
Type *RetType = T->getReturnType();
if (!RetType->isVoidTy())
RetType = StructType::get(RetType, ShadowTy, (Type *)nullptr);
return FunctionType::get(RetType, ArgTypes, T->isVarArg());
}
FunctionType *DataFlowSanitizer::getTrampolineFunctionType(FunctionType *T) {
assert(!T->isVarArg());
llvm::SmallVector<Type *, 4> ArgTypes;
ArgTypes.push_back(T->getPointerTo());
ArgTypes.append(T->param_begin(), T->param_end());
ArgTypes.append(T->getNumParams(), ShadowTy);
Type *RetType = T->getReturnType();
if (!RetType->isVoidTy())
ArgTypes.push_back(ShadowPtrTy);
return FunctionType::get(T->getReturnType(), ArgTypes, false);
}
FunctionType *DataFlowSanitizer::getCustomFunctionType(FunctionType *T) {
llvm::SmallVector<Type *, 4> ArgTypes;
2013-08-28 19:25:12 +08:00
for (FunctionType::param_iterator i = T->param_begin(), e = T->param_end();
i != e; ++i) {
FunctionType *FT;
2013-08-28 19:25:12 +08:00
if (isa<PointerType>(*i) && (FT = dyn_cast<FunctionType>(cast<PointerType>(
*i)->getElementType()))) {
ArgTypes.push_back(getTrampolineFunctionType(FT)->getPointerTo());
ArgTypes.push_back(Type::getInt8PtrTy(*Ctx));
} else {
ArgTypes.push_back(*i);
}
}
for (unsigned i = 0, e = T->getNumParams(); i != e; ++i)
ArgTypes.push_back(ShadowTy);
if (T->isVarArg())
ArgTypes.push_back(ShadowPtrTy);
Type *RetType = T->getReturnType();
if (!RetType->isVoidTy())
ArgTypes.push_back(ShadowPtrTy);
return FunctionType::get(T->getReturnType(), ArgTypes, T->isVarArg());
}
bool DataFlowSanitizer::doInitialization(Module &M) {
llvm::Triple TargetTriple(M.getTargetTriple());
bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
bool IsMIPS64 = TargetTriple.getArch() == llvm::Triple::mips64 ||
TargetTriple.getArch() == llvm::Triple::mips64el;
bool IsAArch64 = TargetTriple.getArch() == llvm::Triple::aarch64 ||
TargetTriple.getArch() == llvm::Triple::aarch64_be;
const DataLayout &DL = M.getDataLayout();
Mod = &M;
Ctx = &M.getContext();
ShadowTy = IntegerType::get(*Ctx, ShadowWidth);
ShadowPtrTy = PointerType::getUnqual(ShadowTy);
IntptrTy = DL.getIntPtrType(*Ctx);
ZeroShadow = ConstantInt::getSigned(ShadowTy, 0);
ShadowPtrMul = ConstantInt::getSigned(IntptrTy, ShadowWidth / 8);
if (IsX86_64)
ShadowPtrMask = ConstantInt::getSigned(IntptrTy, ~0x700000000000LL);
else if (IsMIPS64)
ShadowPtrMask = ConstantInt::getSigned(IntptrTy, ~0xF000000000LL);
// AArch64 supports multiple VMAs and the shadow mask is set at runtime.
else if (IsAArch64)
DFSanRuntimeShadowMask = true;
else
report_fatal_error("unsupported triple");
Type *DFSanUnionArgs[2] = { ShadowTy, ShadowTy };
DFSanUnionFnTy =
FunctionType::get(ShadowTy, DFSanUnionArgs, /*isVarArg=*/ false);
Type *DFSanUnionLoadArgs[2] = { ShadowPtrTy, IntptrTy };
DFSanUnionLoadFnTy =
FunctionType::get(ShadowTy, DFSanUnionLoadArgs, /*isVarArg=*/ false);
DFSanUnimplementedFnTy = FunctionType::get(
Type::getVoidTy(*Ctx), Type::getInt8PtrTy(*Ctx), /*isVarArg=*/false);
Type *DFSanSetLabelArgs[3] = { ShadowTy, Type::getInt8PtrTy(*Ctx), IntptrTy };
DFSanSetLabelFnTy = FunctionType::get(Type::getVoidTy(*Ctx),
DFSanSetLabelArgs, /*isVarArg=*/false);
DFSanNonzeroLabelFnTy = FunctionType::get(
Type::getVoidTy(*Ctx), None, /*isVarArg=*/false);
DFSanVarargWrapperFnTy = FunctionType::get(
Type::getVoidTy(*Ctx), Type::getInt8PtrTy(*Ctx), /*isVarArg=*/false);
if (GetArgTLSPtr) {
Type *ArgTLSTy = ArrayType::get(ShadowTy, 64);
ArgTLS = nullptr;
GetArgTLS = ConstantExpr::getIntToPtr(
ConstantInt::get(IntptrTy, uintptr_t(GetArgTLSPtr)),
PointerType::getUnqual(
FunctionType::get(PointerType::getUnqual(ArgTLSTy),
(Type *)nullptr)));
}
if (GetRetvalTLSPtr) {
RetvalTLS = nullptr;
GetRetvalTLS = ConstantExpr::getIntToPtr(
ConstantInt::get(IntptrTy, uintptr_t(GetRetvalTLSPtr)),
PointerType::getUnqual(
FunctionType::get(PointerType::getUnqual(ShadowTy),
(Type *)nullptr)));
}
ColdCallWeights = MDBuilder(*Ctx).createBranchWeights(1, 1000);
return true;
}
bool DataFlowSanitizer::isInstrumented(const Function *F) {
return !ABIList.isIn(*F, "uninstrumented");
}
bool DataFlowSanitizer::isInstrumented(const GlobalAlias *GA) {
return !ABIList.isIn(*GA, "uninstrumented");
}
DataFlowSanitizer::InstrumentedABI DataFlowSanitizer::getInstrumentedABI() {
return ClArgsABI ? IA_Args : IA_TLS;
}
DataFlowSanitizer::WrapperKind DataFlowSanitizer::getWrapperKind(Function *F) {
if (ABIList.isIn(*F, "functional"))
return WK_Functional;
if (ABIList.isIn(*F, "discard"))
return WK_Discard;
if (ABIList.isIn(*F, "custom"))
return WK_Custom;
return WK_Warning;
}
void DataFlowSanitizer::addGlobalNamePrefix(GlobalValue *GV) {
std::string GVName = GV->getName(), Prefix = "dfs$";
GV->setName(Prefix + GVName);
// Try to change the name of the function in module inline asm. We only do
// this for specific asm directives, currently only ".symver", to try to avoid
// corrupting asm which happens to contain the symbol name as a substring.
// Note that the substitution for .symver assumes that the versioned symbol
// also has an instrumented name.
std::string Asm = GV->getParent()->getModuleInlineAsm();
std::string SearchStr = ".symver " + GVName + ",";
size_t Pos = Asm.find(SearchStr);
if (Pos != std::string::npos) {
Asm.replace(Pos, SearchStr.size(),
".symver " + Prefix + GVName + "," + Prefix);
GV->getParent()->setModuleInlineAsm(Asm);
}
}
Function *
DataFlowSanitizer::buildWrapperFunction(Function *F, StringRef NewFName,
GlobalValue::LinkageTypes NewFLink,
FunctionType *NewFT) {
FunctionType *FT = F->getFunctionType();
Function *NewF = Function::Create(NewFT, NewFLink, NewFName,
F->getParent());
NewF->copyAttributesFrom(F);
NewF->removeAttributes(
AttributeList::ReturnIndex,
AttributeList::get(
F->getContext(), AttributeList::ReturnIndex,
AttributeFuncs::typeIncompatible(NewFT->getReturnType())));
BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", NewF);
if (F->isVarArg()) {
NewF->removeAttributes(
AttributeList::FunctionIndex,
AttributeList().addAttribute(*Ctx, AttributeList::FunctionIndex,
"split-stack"));
CallInst::Create(DFSanVarargWrapperFn,
IRBuilder<>(BB).CreateGlobalStringPtr(F->getName()), "",
BB);
new UnreachableInst(*Ctx, BB);
} else {
std::vector<Value *> Args;
unsigned n = FT->getNumParams();
for (Function::arg_iterator ai = NewF->arg_begin(); n != 0; ++ai, --n)
Args.push_back(&*ai);
CallInst *CI = CallInst::Create(F, Args, "", BB);
if (FT->getReturnType()->isVoidTy())
ReturnInst::Create(*Ctx, BB);
else
ReturnInst::Create(*Ctx, CI, BB);
}
return NewF;
}
Constant *DataFlowSanitizer::getOrBuildTrampolineFunction(FunctionType *FT,
StringRef FName) {
FunctionType *FTT = getTrampolineFunctionType(FT);
Constant *C = Mod->getOrInsertFunction(FName, FTT);
Function *F = dyn_cast<Function>(C);
if (F && F->isDeclaration()) {
F->setLinkage(GlobalValue::LinkOnceODRLinkage);
BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
std::vector<Value *> Args;
Function::arg_iterator AI = F->arg_begin(); ++AI;
for (unsigned N = FT->getNumParams(); N != 0; ++AI, --N)
Args.push_back(&*AI);
CallInst *CI = CallInst::Create(&*F->arg_begin(), Args, "", BB);
ReturnInst *RI;
if (FT->getReturnType()->isVoidTy())
RI = ReturnInst::Create(*Ctx, BB);
else
RI = ReturnInst::Create(*Ctx, CI, BB);
DFSanFunction DFSF(*this, F, /*IsNativeABI=*/true);
Function::arg_iterator ValAI = F->arg_begin(), ShadowAI = AI; ++ValAI;
for (unsigned N = FT->getNumParams(); N != 0; ++ValAI, ++ShadowAI, --N)
DFSF.ValShadowMap[&*ValAI] = &*ShadowAI;
DFSanVisitor(DFSF).visitCallInst(*CI);
if (!FT->getReturnType()->isVoidTy())
new StoreInst(DFSF.getShadow(RI->getReturnValue()),
&*std::prev(F->arg_end()), RI);
}
return C;
}
bool DataFlowSanitizer::runOnModule(Module &M) {
if (ABIList.isIn(M, "skip"))
return false;
if (!GetArgTLSPtr) {
Type *ArgTLSTy = ArrayType::get(ShadowTy, 64);
ArgTLS = Mod->getOrInsertGlobal("__dfsan_arg_tls", ArgTLSTy);
if (GlobalVariable *G = dyn_cast<GlobalVariable>(ArgTLS))
G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
}
if (!GetRetvalTLSPtr) {
RetvalTLS = Mod->getOrInsertGlobal("__dfsan_retval_tls", ShadowTy);
if (GlobalVariable *G = dyn_cast<GlobalVariable>(RetvalTLS))
G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
}
ExternalShadowMask =
Mod->getOrInsertGlobal(kDFSanExternShadowPtrMask, IntptrTy);
DFSanUnionFn = Mod->getOrInsertFunction("__dfsan_union", DFSanUnionFnTy);
if (Function *F = dyn_cast<Function>(DFSanUnionFn)) {
F->addAttribute(AttributeList::FunctionIndex, Attribute::NoUnwind);
F->addAttribute(AttributeList::FunctionIndex, Attribute::ReadNone);
F->addAttribute(AttributeList::ReturnIndex, Attribute::ZExt);
F->addAttribute(1, Attribute::ZExt);
F->addAttribute(2, Attribute::ZExt);
}
DFSanCheckedUnionFn = Mod->getOrInsertFunction("dfsan_union", DFSanUnionFnTy);
if (Function *F = dyn_cast<Function>(DFSanCheckedUnionFn)) {
F->addAttribute(AttributeList::FunctionIndex, Attribute::NoUnwind);
F->addAttribute(AttributeList::FunctionIndex, Attribute::ReadNone);
F->addAttribute(AttributeList::ReturnIndex, Attribute::ZExt);
F->addAttribute(1, Attribute::ZExt);
F->addAttribute(2, Attribute::ZExt);
}
DFSanUnionLoadFn =
Mod->getOrInsertFunction("__dfsan_union_load", DFSanUnionLoadFnTy);
if (Function *F = dyn_cast<Function>(DFSanUnionLoadFn)) {
F->addAttribute(AttributeList::FunctionIndex, Attribute::NoUnwind);
F->addAttribute(AttributeList::FunctionIndex, Attribute::ReadOnly);
F->addAttribute(AttributeList::ReturnIndex, Attribute::ZExt);
}
DFSanUnimplementedFn =
Mod->getOrInsertFunction("__dfsan_unimplemented", DFSanUnimplementedFnTy);
DFSanSetLabelFn =
Mod->getOrInsertFunction("__dfsan_set_label", DFSanSetLabelFnTy);
if (Function *F = dyn_cast<Function>(DFSanSetLabelFn)) {
F->addAttribute(1, Attribute::ZExt);
}
DFSanNonzeroLabelFn =
Mod->getOrInsertFunction("__dfsan_nonzero_label", DFSanNonzeroLabelFnTy);
DFSanVarargWrapperFn = Mod->getOrInsertFunction("__dfsan_vararg_wrapper",
DFSanVarargWrapperFnTy);
std::vector<Function *> FnsToInstrument;
llvm::SmallPtrSet<Function *, 2> FnsWithNativeABI;
for (Function &i : M) {
if (!i.isIntrinsic() &&
&i != DFSanUnionFn &&
&i != DFSanCheckedUnionFn &&
&i != DFSanUnionLoadFn &&
&i != DFSanUnimplementedFn &&
&i != DFSanSetLabelFn &&
&i != DFSanNonzeroLabelFn &&
&i != DFSanVarargWrapperFn)
FnsToInstrument.push_back(&i);
}
// Give function aliases prefixes when necessary, and build wrappers where the
// instrumentedness is inconsistent.
for (Module::alias_iterator i = M.alias_begin(), e = M.alias_end(); i != e;) {
GlobalAlias *GA = &*i;
++i;
// Don't stop on weak. We assume people aren't playing games with the
// instrumentedness of overridden weak aliases.
if (auto F = dyn_cast<Function>(GA->getBaseObject())) {
bool GAInst = isInstrumented(GA), FInst = isInstrumented(F);
if (GAInst && FInst) {
addGlobalNamePrefix(GA);
} else if (GAInst != FInst) {
// Non-instrumented alias of an instrumented function, or vice versa.
// Replace the alias with a native-ABI wrapper of the aliasee. The pass
// below will take care of instrumenting it.
Function *NewF =
buildWrapperFunction(F, "", GA->getLinkage(), F->getFunctionType());
GA->replaceAllUsesWith(ConstantExpr::getBitCast(NewF, GA->getType()));
NewF->takeName(GA);
GA->eraseFromParent();
FnsToInstrument.push_back(NewF);
}
}
}
AttrBuilder B;
B.addAttribute(Attribute::ReadOnly).addAttribute(Attribute::ReadNone);
ReadOnlyNoneAttrs = AttributeList::get(*Ctx, AttributeList::FunctionIndex, B);
// First, change the ABI of every function in the module. ABI-listed
// functions keep their original ABI and get a wrapper function.
for (std::vector<Function *>::iterator i = FnsToInstrument.begin(),
e = FnsToInstrument.end();
i != e; ++i) {
Function &F = **i;
FunctionType *FT = F.getFunctionType();
bool IsZeroArgsVoidRet = (FT->getNumParams() == 0 && !FT->isVarArg() &&
FT->getReturnType()->isVoidTy());
if (isInstrumented(&F)) {
// Instrumented functions get a 'dfs$' prefix. This allows us to more
// easily identify cases of mismatching ABIs.
if (getInstrumentedABI() == IA_Args && !IsZeroArgsVoidRet) {
FunctionType *NewFT = getArgsFunctionType(FT);
Function *NewF = Function::Create(NewFT, F.getLinkage(), "", &M);
NewF->copyAttributesFrom(&F);
NewF->removeAttributes(
AttributeList::ReturnIndex,
AttributeList::get(
NewF->getContext(), AttributeList::ReturnIndex,
AttributeFuncs::typeIncompatible(NewFT->getReturnType())));
for (Function::arg_iterator FArg = F.arg_begin(),
NewFArg = NewF->arg_begin(),
FArgEnd = F.arg_end();
FArg != FArgEnd; ++FArg, ++NewFArg) {
FArg->replaceAllUsesWith(&*NewFArg);
}
NewF->getBasicBlockList().splice(NewF->begin(), F.getBasicBlockList());
[C++11] Add range based accessors for the Use-Def chain of a Value. This requires a number of steps. 1) Move value_use_iterator into the Value class as an implementation detail 2) Change it to actually be a *Use* iterator rather than a *User* iterator. 3) Add an adaptor which is a User iterator that always looks through the Use to the User. 4) Wrap these in Value::use_iterator and Value::user_iterator typedefs. 5) Add the range adaptors as Value::uses() and Value::users(). 6) Update *all* of the callers to correctly distinguish between whether they wanted a use_iterator (and to explicitly dig out the User when needed), or a user_iterator which makes the Use itself totally opaque. Because #6 requires churning essentially everything that walked the Use-Def chains, I went ahead and added all of the range adaptors and switched them to range-based loops where appropriate. Also because the renaming requires at least churning every line of code, it didn't make any sense to split these up into multiple commits -- all of which would touch all of the same lies of code. The result is still not quite optimal. The Value::use_iterator is a nice regular iterator, but Value::user_iterator is an iterator over User*s rather than over the User objects themselves. As a consequence, it fits a bit awkwardly into the range-based world and it has the weird extra-dereferencing 'operator->' that so many of our iterators have. I think this could be fixed by providing something which transforms a range of T&s into a range of T*s, but that *can* be separated into another patch, and it isn't yet 100% clear whether this is the right move. However, this change gets us most of the benefit and cleans up a substantial amount of code around Use and User. =] llvm-svn: 203364
2014-03-09 11:16:01 +08:00
for (Function::user_iterator UI = F.user_begin(), UE = F.user_end();
UI != UE;) {
BlockAddress *BA = dyn_cast<BlockAddress>(*UI);
++UI;
if (BA) {
BA->replaceAllUsesWith(
BlockAddress::get(NewF, BA->getBasicBlock()));
delete BA;
}
}
F.replaceAllUsesWith(
ConstantExpr::getBitCast(NewF, PointerType::getUnqual(FT)));
NewF->takeName(&F);
F.eraseFromParent();
*i = NewF;
addGlobalNamePrefix(NewF);
} else {
addGlobalNamePrefix(&F);
}
} else if (!IsZeroArgsVoidRet || getWrapperKind(&F) == WK_Custom) {
// Build a wrapper function for F. The wrapper simply calls F, and is
// added to FnsToInstrument so that any instrumentation according to its
// WrapperKind is done in the second pass below.
FunctionType *NewFT = getInstrumentedABI() == IA_Args
? getArgsFunctionType(FT)
: FT;
2013-08-23 15:42:51 +08:00
Function *NewF = buildWrapperFunction(
&F, std::string("dfsw$") + std::string(F.getName()),
GlobalValue::LinkOnceODRLinkage, NewFT);
if (getInstrumentedABI() == IA_TLS)
NewF->removeAttributes(AttributeList::FunctionIndex, ReadOnlyNoneAttrs);
Value *WrappedFnCst =
ConstantExpr::getBitCast(NewF, PointerType::getUnqual(FT));
F.replaceAllUsesWith(WrappedFnCst);
UnwrappedFnMap[WrappedFnCst] = &F;
*i = NewF;
if (!F.isDeclaration()) {
// This function is probably defining an interposition of an
// uninstrumented function and hence needs to keep the original ABI.
// But any functions it may call need to use the instrumented ABI, so
// we instrument it in a mode which preserves the original ABI.
FnsWithNativeABI.insert(&F);
// This code needs to rebuild the iterators, as they may be invalidated
// by the push_back, taking care that the new range does not include
// any functions added by this code.
size_t N = i - FnsToInstrument.begin(),
Count = e - FnsToInstrument.begin();
FnsToInstrument.push_back(&F);
i = FnsToInstrument.begin() + N;
e = FnsToInstrument.begin() + Count;
}
// Hopefully, nobody will try to indirectly call a vararg
// function... yet.
} else if (FT->isVarArg()) {
UnwrappedFnMap[&F] = &F;
*i = nullptr;
}
}
for (Function *i : FnsToInstrument) {
if (!i || i->isDeclaration())
continue;
removeUnreachableBlocks(*i);
DFSanFunction DFSF(*this, i, FnsWithNativeABI.count(i));
// DFSanVisitor may create new basic blocks, which confuses df_iterator.
// Build a copy of the list before iterating over it.
llvm::SmallVector<BasicBlock *, 4> BBList(depth_first(&i->getEntryBlock()));
for (BasicBlock *i : BBList) {
Instruction *Inst = &i->front();
while (1) {
// DFSanVisitor may split the current basic block, changing the current
// instruction's next pointer and moving the next instruction to the
// tail block from which we should continue.
Instruction *Next = Inst->getNextNode();
// DFSanVisitor may delete Inst, so keep track of whether it was a
// terminator.
bool IsTerminator = isa<TerminatorInst>(Inst);
if (!DFSF.SkipInsts.count(Inst))
DFSanVisitor(DFSF).visit(Inst);
if (IsTerminator)
break;
Inst = Next;
}
}
// We will not necessarily be able to compute the shadow for every phi node
// until we have visited every block. Therefore, the code that handles phi
// nodes adds them to the PHIFixups list so that they can be properly
// handled here.
for (std::vector<std::pair<PHINode *, PHINode *> >::iterator
i = DFSF.PHIFixups.begin(),
e = DFSF.PHIFixups.end();
i != e; ++i) {
for (unsigned val = 0, n = i->first->getNumIncomingValues(); val != n;
++val) {
i->second->setIncomingValue(
val, DFSF.getShadow(i->first->getIncomingValue(val)));
}
}
// -dfsan-debug-nonzero-labels will split the CFG in all kinds of crazy
// places (i.e. instructions in basic blocks we haven't even begun visiting
// yet). To make our life easier, do this work in a pass after the main
// instrumentation.
if (ClDebugNonzeroLabels) {
for (Value *V : DFSF.NonZeroChecks) {
Instruction *Pos;
if (Instruction *I = dyn_cast<Instruction>(V))
Pos = I->getNextNode();
else
Pos = &DFSF.F->getEntryBlock().front();
while (isa<PHINode>(Pos) || isa<AllocaInst>(Pos))
Pos = Pos->getNextNode();
IRBuilder<> IRB(Pos);
Value *Ne = IRB.CreateICmpNE(V, DFSF.DFS.ZeroShadow);
BranchInst *BI = cast<BranchInst>(SplitBlockAndInsertIfThen(
Ne, Pos, /*Unreachable=*/false, ColdCallWeights));
IRBuilder<> ThenIRB(BI);
ThenIRB.CreateCall(DFSF.DFS.DFSanNonzeroLabelFn, {});
}
}
}
return false;
}
Value *DFSanFunction::getArgTLSPtr() {
if (ArgTLSPtr)
return ArgTLSPtr;
if (DFS.ArgTLS)
return ArgTLSPtr = DFS.ArgTLS;
IRBuilder<> IRB(&F->getEntryBlock().front());
return ArgTLSPtr = IRB.CreateCall(DFS.GetArgTLS, {});
}
Value *DFSanFunction::getRetvalTLS() {
if (RetvalTLSPtr)
return RetvalTLSPtr;
if (DFS.RetvalTLS)
return RetvalTLSPtr = DFS.RetvalTLS;
IRBuilder<> IRB(&F->getEntryBlock().front());
return RetvalTLSPtr = IRB.CreateCall(DFS.GetRetvalTLS, {});
}
Value *DFSanFunction::getArgTLS(unsigned Idx, Instruction *Pos) {
IRBuilder<> IRB(Pos);
return IRB.CreateConstGEP2_64(getArgTLSPtr(), 0, Idx);
}
Value *DFSanFunction::getShadow(Value *V) {
if (!isa<Argument>(V) && !isa<Instruction>(V))
return DFS.ZeroShadow;
Value *&Shadow = ValShadowMap[V];
if (!Shadow) {
if (Argument *A = dyn_cast<Argument>(V)) {
if (IsNativeABI)
return DFS.ZeroShadow;
switch (IA) {
case DataFlowSanitizer::IA_TLS: {
Value *ArgTLSPtr = getArgTLSPtr();
Instruction *ArgTLSPos =
DFS.ArgTLS ? &*F->getEntryBlock().begin()
: cast<Instruction>(ArgTLSPtr)->getNextNode();
IRBuilder<> IRB(ArgTLSPos);
Shadow = IRB.CreateLoad(getArgTLS(A->getArgNo(), ArgTLSPos));
break;
}
case DataFlowSanitizer::IA_Args: {
unsigned ArgIdx = A->getArgNo() + F->arg_size() / 2;
Function::arg_iterator i = F->arg_begin();
while (ArgIdx--)
++i;
Shadow = &*i;
assert(Shadow->getType() == DFS.ShadowTy);
break;
}
}
NonZeroChecks.push_back(Shadow);
} else {
Shadow = DFS.ZeroShadow;
}
}
return Shadow;
}
void DFSanFunction::setShadow(Instruction *I, Value *Shadow) {
assert(!ValShadowMap.count(I));
assert(Shadow->getType() == DFS.ShadowTy);
ValShadowMap[I] = Shadow;
}
Value *DataFlowSanitizer::getShadowAddress(Value *Addr, Instruction *Pos) {
assert(Addr != RetvalTLS && "Reinstrumenting?");
IRBuilder<> IRB(Pos);
Value *ShadowPtrMaskValue;
if (DFSanRuntimeShadowMask)
ShadowPtrMaskValue = IRB.CreateLoad(IntptrTy, ExternalShadowMask);
else
ShadowPtrMaskValue = ShadowPtrMask;
return IRB.CreateIntToPtr(
IRB.CreateMul(
IRB.CreateAnd(IRB.CreatePtrToInt(Addr, IntptrTy),
IRB.CreatePtrToInt(ShadowPtrMaskValue, IntptrTy)),
ShadowPtrMul),
ShadowPtrTy);
}
// Generates IR to compute the union of the two given shadows, inserting it
// before Pos. Returns the computed union Value.
Value *DFSanFunction::combineShadows(Value *V1, Value *V2, Instruction *Pos) {
if (V1 == DFS.ZeroShadow)
return V2;
if (V2 == DFS.ZeroShadow)
return V1;
if (V1 == V2)
return V1;
auto V1Elems = ShadowElements.find(V1);
auto V2Elems = ShadowElements.find(V2);
if (V1Elems != ShadowElements.end() && V2Elems != ShadowElements.end()) {
if (std::includes(V1Elems->second.begin(), V1Elems->second.end(),
V2Elems->second.begin(), V2Elems->second.end())) {
return V1;
} else if (std::includes(V2Elems->second.begin(), V2Elems->second.end(),
V1Elems->second.begin(), V1Elems->second.end())) {
return V2;
}
} else if (V1Elems != ShadowElements.end()) {
if (V1Elems->second.count(V2))
return V1;
} else if (V2Elems != ShadowElements.end()) {
if (V2Elems->second.count(V1))
return V2;
}
auto Key = std::make_pair(V1, V2);
if (V1 > V2)
std::swap(Key.first, Key.second);
CachedCombinedShadow &CCS = CachedCombinedShadows[Key];
if (CCS.Block && DT.dominates(CCS.Block, Pos->getParent()))
return CCS.Shadow;
IRBuilder<> IRB(Pos);
if (AvoidNewBlocks) {
CallInst *Call = IRB.CreateCall(DFS.DFSanCheckedUnionFn, {V1, V2});
Call->addAttribute(AttributeList::ReturnIndex, Attribute::ZExt);
Call->addAttribute(1, Attribute::ZExt);
Call->addAttribute(2, Attribute::ZExt);
CCS.Block = Pos->getParent();
CCS.Shadow = Call;
} else {
BasicBlock *Head = Pos->getParent();
Value *Ne = IRB.CreateICmpNE(V1, V2);
BranchInst *BI = cast<BranchInst>(SplitBlockAndInsertIfThen(
Ne, Pos, /*Unreachable=*/false, DFS.ColdCallWeights, &DT));
IRBuilder<> ThenIRB(BI);
CallInst *Call = ThenIRB.CreateCall(DFS.DFSanUnionFn, {V1, V2});
Call->addAttribute(AttributeList::ReturnIndex, Attribute::ZExt);
Call->addAttribute(1, Attribute::ZExt);
Call->addAttribute(2, Attribute::ZExt);
BasicBlock *Tail = BI->getSuccessor(0);
PHINode *Phi = PHINode::Create(DFS.ShadowTy, 2, "", &Tail->front());
Phi->addIncoming(Call, Call->getParent());
Phi->addIncoming(V1, Head);
CCS.Block = Tail;
CCS.Shadow = Phi;
}
std::set<Value *> UnionElems;
if (V1Elems != ShadowElements.end()) {
UnionElems = V1Elems->second;
} else {
UnionElems.insert(V1);
}
if (V2Elems != ShadowElements.end()) {
UnionElems.insert(V2Elems->second.begin(), V2Elems->second.end());
} else {
UnionElems.insert(V2);
}
ShadowElements[CCS.Shadow] = std::move(UnionElems);
return CCS.Shadow;
}
// A convenience function which folds the shadows of each of the operands
// of the provided instruction Inst, inserting the IR before Inst. Returns
// the computed union Value.
Value *DFSanFunction::combineOperandShadows(Instruction *Inst) {
if (Inst->getNumOperands() == 0)
return DFS.ZeroShadow;
Value *Shadow = getShadow(Inst->getOperand(0));
for (unsigned i = 1, n = Inst->getNumOperands(); i != n; ++i) {
Shadow = combineShadows(Shadow, getShadow(Inst->getOperand(i)), Inst);
}
return Shadow;
}
void DFSanVisitor::visitOperandShadowInst(Instruction &I) {
Value *CombinedShadow = DFSF.combineOperandShadows(&I);
DFSF.setShadow(&I, CombinedShadow);
}
// Generates IR to load shadow corresponding to bytes [Addr, Addr+Size), where
// Addr has alignment Align, and take the union of each of those shadows.
Value *DFSanFunction::loadShadow(Value *Addr, uint64_t Size, uint64_t Align,
Instruction *Pos) {
if (AllocaInst *AI = dyn_cast<AllocaInst>(Addr)) {
llvm::DenseMap<AllocaInst *, AllocaInst *>::iterator i =
AllocaShadowMap.find(AI);
if (i != AllocaShadowMap.end()) {
IRBuilder<> IRB(Pos);
return IRB.CreateLoad(i->second);
}
}
uint64_t ShadowAlign = Align * DFS.ShadowWidth / 8;
SmallVector<Value *, 2> Objs;
GetUnderlyingObjects(Addr, Objs, Pos->getModule()->getDataLayout());
bool AllConstants = true;
for (Value *Obj : Objs) {
if (isa<Function>(Obj) || isa<BlockAddress>(Obj))
continue;
if (isa<GlobalVariable>(Obj) && cast<GlobalVariable>(Obj)->isConstant())
continue;
AllConstants = false;
break;
}
if (AllConstants)
return DFS.ZeroShadow;
Value *ShadowAddr = DFS.getShadowAddress(Addr, Pos);
switch (Size) {
case 0:
return DFS.ZeroShadow;
case 1: {
LoadInst *LI = new LoadInst(ShadowAddr, "", Pos);
LI->setAlignment(ShadowAlign);
return LI;
}
case 2: {
IRBuilder<> IRB(Pos);
Value *ShadowAddr1 = IRB.CreateGEP(DFS.ShadowTy, ShadowAddr,
ConstantInt::get(DFS.IntptrTy, 1));
return combineShadows(IRB.CreateAlignedLoad(ShadowAddr, ShadowAlign),
IRB.CreateAlignedLoad(ShadowAddr1, ShadowAlign), Pos);
}
}
if (!AvoidNewBlocks && Size % (64 / DFS.ShadowWidth) == 0) {
// Fast path for the common case where each byte has identical shadow: load
// shadow 64 bits at a time, fall out to a __dfsan_union_load call if any
// shadow is non-equal.
BasicBlock *FallbackBB = BasicBlock::Create(*DFS.Ctx, "", F);
IRBuilder<> FallbackIRB(FallbackBB);
CallInst *FallbackCall = FallbackIRB.CreateCall(
DFS.DFSanUnionLoadFn,
{ShadowAddr, ConstantInt::get(DFS.IntptrTy, Size)});
FallbackCall->addAttribute(AttributeList::ReturnIndex, Attribute::ZExt);
// Compare each of the shadows stored in the loaded 64 bits to each other,
// by computing (WideShadow rotl ShadowWidth) == WideShadow.
IRBuilder<> IRB(Pos);
Value *WideAddr =
IRB.CreateBitCast(ShadowAddr, Type::getInt64PtrTy(*DFS.Ctx));
Value *WideShadow = IRB.CreateAlignedLoad(WideAddr, ShadowAlign);
Value *TruncShadow = IRB.CreateTrunc(WideShadow, DFS.ShadowTy);
Value *ShlShadow = IRB.CreateShl(WideShadow, DFS.ShadowWidth);
Value *ShrShadow = IRB.CreateLShr(WideShadow, 64 - DFS.ShadowWidth);
Value *RotShadow = IRB.CreateOr(ShlShadow, ShrShadow);
Value *ShadowsEq = IRB.CreateICmpEQ(WideShadow, RotShadow);
BasicBlock *Head = Pos->getParent();
BasicBlock *Tail = Head->splitBasicBlock(Pos->getIterator());
if (DomTreeNode *OldNode = DT.getNode(Head)) {
std::vector<DomTreeNode *> Children(OldNode->begin(), OldNode->end());
DomTreeNode *NewNode = DT.addNewBlock(Tail, Head);
for (auto Child : Children)
DT.changeImmediateDominator(Child, NewNode);
}
// In the following code LastBr will refer to the previous basic block's
// conditional branch instruction, whose true successor is fixed up to point
// to the next block during the loop below or to the tail after the final
// iteration.
BranchInst *LastBr = BranchInst::Create(FallbackBB, FallbackBB, ShadowsEq);
ReplaceInstWithInst(Head->getTerminator(), LastBr);
DT.addNewBlock(FallbackBB, Head);
for (uint64_t Ofs = 64 / DFS.ShadowWidth; Ofs != Size;
Ofs += 64 / DFS.ShadowWidth) {
BasicBlock *NextBB = BasicBlock::Create(*DFS.Ctx, "", F);
DT.addNewBlock(NextBB, LastBr->getParent());
IRBuilder<> NextIRB(NextBB);
WideAddr = NextIRB.CreateGEP(Type::getInt64Ty(*DFS.Ctx), WideAddr,
ConstantInt::get(DFS.IntptrTy, 1));
Value *NextWideShadow = NextIRB.CreateAlignedLoad(WideAddr, ShadowAlign);
ShadowsEq = NextIRB.CreateICmpEQ(WideShadow, NextWideShadow);
LastBr->setSuccessor(0, NextBB);
LastBr = NextIRB.CreateCondBr(ShadowsEq, FallbackBB, FallbackBB);
}
LastBr->setSuccessor(0, Tail);
FallbackIRB.CreateBr(Tail);
PHINode *Shadow = PHINode::Create(DFS.ShadowTy, 2, "", &Tail->front());
Shadow->addIncoming(FallbackCall, FallbackBB);
Shadow->addIncoming(TruncShadow, LastBr->getParent());
return Shadow;
}
IRBuilder<> IRB(Pos);
CallInst *FallbackCall = IRB.CreateCall(
DFS.DFSanUnionLoadFn, {ShadowAddr, ConstantInt::get(DFS.IntptrTy, Size)});
FallbackCall->addAttribute(AttributeList::ReturnIndex, Attribute::ZExt);
return FallbackCall;
}
void DFSanVisitor::visitLoadInst(LoadInst &LI) {
auto &DL = LI.getModule()->getDataLayout();
uint64_t Size = DL.getTypeStoreSize(LI.getType());
if (Size == 0) {
DFSF.setShadow(&LI, DFSF.DFS.ZeroShadow);
return;
}
uint64_t Align;
if (ClPreserveAlignment) {
Align = LI.getAlignment();
if (Align == 0)
Align = DL.getABITypeAlignment(LI.getType());
} else {
Align = 1;
}
IRBuilder<> IRB(&LI);
Value *Shadow = DFSF.loadShadow(LI.getPointerOperand(), Size, Align, &LI);
if (ClCombinePointerLabelsOnLoad) {
Value *PtrShadow = DFSF.getShadow(LI.getPointerOperand());
Shadow = DFSF.combineShadows(Shadow, PtrShadow, &LI);
}
if (Shadow != DFSF.DFS.ZeroShadow)
DFSF.NonZeroChecks.push_back(Shadow);
DFSF.setShadow(&LI, Shadow);
}
void DFSanFunction::storeShadow(Value *Addr, uint64_t Size, uint64_t Align,
Value *Shadow, Instruction *Pos) {
if (AllocaInst *AI = dyn_cast<AllocaInst>(Addr)) {
llvm::DenseMap<AllocaInst *, AllocaInst *>::iterator i =
AllocaShadowMap.find(AI);
if (i != AllocaShadowMap.end()) {
IRBuilder<> IRB(Pos);
IRB.CreateStore(Shadow, i->second);
return;
}
}
uint64_t ShadowAlign = Align * DFS.ShadowWidth / 8;
IRBuilder<> IRB(Pos);
Value *ShadowAddr = DFS.getShadowAddress(Addr, Pos);
if (Shadow == DFS.ZeroShadow) {
IntegerType *ShadowTy = IntegerType::get(*DFS.Ctx, Size * DFS.ShadowWidth);
Value *ExtZeroShadow = ConstantInt::get(ShadowTy, 0);
Value *ExtShadowAddr =
IRB.CreateBitCast(ShadowAddr, PointerType::getUnqual(ShadowTy));
IRB.CreateAlignedStore(ExtZeroShadow, ExtShadowAddr, ShadowAlign);
return;
}
const unsigned ShadowVecSize = 128 / DFS.ShadowWidth;
uint64_t Offset = 0;
if (Size >= ShadowVecSize) {
VectorType *ShadowVecTy = VectorType::get(DFS.ShadowTy, ShadowVecSize);
Value *ShadowVec = UndefValue::get(ShadowVecTy);
for (unsigned i = 0; i != ShadowVecSize; ++i) {
ShadowVec = IRB.CreateInsertElement(
ShadowVec, Shadow, ConstantInt::get(Type::getInt32Ty(*DFS.Ctx), i));
}
Value *ShadowVecAddr =
IRB.CreateBitCast(ShadowAddr, PointerType::getUnqual(ShadowVecTy));
do {
Value *CurShadowVecAddr =
IRB.CreateConstGEP1_32(ShadowVecTy, ShadowVecAddr, Offset);
IRB.CreateAlignedStore(ShadowVec, CurShadowVecAddr, ShadowAlign);
Size -= ShadowVecSize;
++Offset;
} while (Size >= ShadowVecSize);
Offset *= ShadowVecSize;
}
while (Size > 0) {
Value *CurShadowAddr =
IRB.CreateConstGEP1_32(DFS.ShadowTy, ShadowAddr, Offset);
IRB.CreateAlignedStore(Shadow, CurShadowAddr, ShadowAlign);
--Size;
++Offset;
}
}
void DFSanVisitor::visitStoreInst(StoreInst &SI) {
auto &DL = SI.getModule()->getDataLayout();
uint64_t Size = DL.getTypeStoreSize(SI.getValueOperand()->getType());
if (Size == 0)
return;
uint64_t Align;
if (ClPreserveAlignment) {
Align = SI.getAlignment();
if (Align == 0)
Align = DL.getABITypeAlignment(SI.getValueOperand()->getType());
} else {
Align = 1;
}
Value* Shadow = DFSF.getShadow(SI.getValueOperand());
if (ClCombinePointerLabelsOnStore) {
Value *PtrShadow = DFSF.getShadow(SI.getPointerOperand());
Shadow = DFSF.combineShadows(Shadow, PtrShadow, &SI);
}
DFSF.storeShadow(SI.getPointerOperand(), Size, Align, Shadow, &SI);
}
void DFSanVisitor::visitBinaryOperator(BinaryOperator &BO) {
visitOperandShadowInst(BO);
}
void DFSanVisitor::visitCastInst(CastInst &CI) { visitOperandShadowInst(CI); }
void DFSanVisitor::visitCmpInst(CmpInst &CI) { visitOperandShadowInst(CI); }
void DFSanVisitor::visitGetElementPtrInst(GetElementPtrInst &GEPI) {
visitOperandShadowInst(GEPI);
}
void DFSanVisitor::visitExtractElementInst(ExtractElementInst &I) {
visitOperandShadowInst(I);
}
void DFSanVisitor::visitInsertElementInst(InsertElementInst &I) {
visitOperandShadowInst(I);
}
void DFSanVisitor::visitShuffleVectorInst(ShuffleVectorInst &I) {
visitOperandShadowInst(I);
}
void DFSanVisitor::visitExtractValueInst(ExtractValueInst &I) {
visitOperandShadowInst(I);
}
void DFSanVisitor::visitInsertValueInst(InsertValueInst &I) {
visitOperandShadowInst(I);
}
void DFSanVisitor::visitAllocaInst(AllocaInst &I) {
bool AllLoadsStores = true;
[C++11] Add range based accessors for the Use-Def chain of a Value. This requires a number of steps. 1) Move value_use_iterator into the Value class as an implementation detail 2) Change it to actually be a *Use* iterator rather than a *User* iterator. 3) Add an adaptor which is a User iterator that always looks through the Use to the User. 4) Wrap these in Value::use_iterator and Value::user_iterator typedefs. 5) Add the range adaptors as Value::uses() and Value::users(). 6) Update *all* of the callers to correctly distinguish between whether they wanted a use_iterator (and to explicitly dig out the User when needed), or a user_iterator which makes the Use itself totally opaque. Because #6 requires churning essentially everything that walked the Use-Def chains, I went ahead and added all of the range adaptors and switched them to range-based loops where appropriate. Also because the renaming requires at least churning every line of code, it didn't make any sense to split these up into multiple commits -- all of which would touch all of the same lies of code. The result is still not quite optimal. The Value::use_iterator is a nice regular iterator, but Value::user_iterator is an iterator over User*s rather than over the User objects themselves. As a consequence, it fits a bit awkwardly into the range-based world and it has the weird extra-dereferencing 'operator->' that so many of our iterators have. I think this could be fixed by providing something which transforms a range of T&s into a range of T*s, but that *can* be separated into another patch, and it isn't yet 100% clear whether this is the right move. However, this change gets us most of the benefit and cleans up a substantial amount of code around Use and User. =] llvm-svn: 203364
2014-03-09 11:16:01 +08:00
for (User *U : I.users()) {
if (isa<LoadInst>(U))
continue;
[C++11] Add range based accessors for the Use-Def chain of a Value. This requires a number of steps. 1) Move value_use_iterator into the Value class as an implementation detail 2) Change it to actually be a *Use* iterator rather than a *User* iterator. 3) Add an adaptor which is a User iterator that always looks through the Use to the User. 4) Wrap these in Value::use_iterator and Value::user_iterator typedefs. 5) Add the range adaptors as Value::uses() and Value::users(). 6) Update *all* of the callers to correctly distinguish between whether they wanted a use_iterator (and to explicitly dig out the User when needed), or a user_iterator which makes the Use itself totally opaque. Because #6 requires churning essentially everything that walked the Use-Def chains, I went ahead and added all of the range adaptors and switched them to range-based loops where appropriate. Also because the renaming requires at least churning every line of code, it didn't make any sense to split these up into multiple commits -- all of which would touch all of the same lies of code. The result is still not quite optimal. The Value::use_iterator is a nice regular iterator, but Value::user_iterator is an iterator over User*s rather than over the User objects themselves. As a consequence, it fits a bit awkwardly into the range-based world and it has the weird extra-dereferencing 'operator->' that so many of our iterators have. I think this could be fixed by providing something which transforms a range of T&s into a range of T*s, but that *can* be separated into another patch, and it isn't yet 100% clear whether this is the right move. However, this change gets us most of the benefit and cleans up a substantial amount of code around Use and User. =] llvm-svn: 203364
2014-03-09 11:16:01 +08:00
if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
if (SI->getPointerOperand() == &I)
continue;
}
AllLoadsStores = false;
break;
}
if (AllLoadsStores) {
IRBuilder<> IRB(&I);
DFSF.AllocaShadowMap[&I] = IRB.CreateAlloca(DFSF.DFS.ShadowTy);
}
DFSF.setShadow(&I, DFSF.DFS.ZeroShadow);
}
void DFSanVisitor::visitSelectInst(SelectInst &I) {
Value *CondShadow = DFSF.getShadow(I.getCondition());
Value *TrueShadow = DFSF.getShadow(I.getTrueValue());
Value *FalseShadow = DFSF.getShadow(I.getFalseValue());
if (isa<VectorType>(I.getCondition()->getType())) {
DFSF.setShadow(
&I,
DFSF.combineShadows(
CondShadow, DFSF.combineShadows(TrueShadow, FalseShadow, &I), &I));
} else {
Value *ShadowSel;
if (TrueShadow == FalseShadow) {
ShadowSel = TrueShadow;
} else {
ShadowSel =
SelectInst::Create(I.getCondition(), TrueShadow, FalseShadow, "", &I);
}
DFSF.setShadow(&I, DFSF.combineShadows(CondShadow, ShadowSel, &I));
}
}
void DFSanVisitor::visitMemSetInst(MemSetInst &I) {
IRBuilder<> IRB(&I);
Value *ValShadow = DFSF.getShadow(I.getValue());
IRB.CreateCall(DFSF.DFS.DFSanSetLabelFn,
{ValShadow, IRB.CreateBitCast(I.getDest(), Type::getInt8PtrTy(
*DFSF.DFS.Ctx)),
IRB.CreateZExtOrTrunc(I.getLength(), DFSF.DFS.IntptrTy)});
}
void DFSanVisitor::visitMemTransferInst(MemTransferInst &I) {
IRBuilder<> IRB(&I);
Value *DestShadow = DFSF.DFS.getShadowAddress(I.getDest(), &I);
Value *SrcShadow = DFSF.DFS.getShadowAddress(I.getSource(), &I);
Value *LenShadow = IRB.CreateMul(
I.getLength(),
ConstantInt::get(I.getLength()->getType(), DFSF.DFS.ShadowWidth / 8));
Value *AlignShadow;
Change memcpy/memset/memmove to have dest and source alignments. Note, this was reviewed (and more details are in) http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html These intrinsics currently have an explicit alignment argument which is required to be a constant integer. It represents the alignment of the source and dest, and so must be the minimum of those. This change allows source and dest to each have their own alignments by using the alignment attribute on their arguments. The alignment argument itself is removed. There are a few places in the code for which the code needs to be checked by an expert as to whether using only src/dest alignment is safe. For those places, they currently take the minimum of src/dest alignments which matches the current behaviour. For example, code which used to read: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 500, i32 8, i1 false) will now read: call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 8 %dest, i8* align 8 %src, i32 500, i1 false) For out of tree owners, I was able to strip alignment from calls using sed by replacing: (call.*llvm\.memset.*)i32\ [0-9]*\,\ i1 false\) with: $1i1 false) and similarly for memmove and memcpy. I then added back in alignment to test cases which needed it. A similar commit will be made to clang which actually has many differences in alignment as now IRBuilder can generate different source/dest alignments on calls. In IRBuilder itself, a new argument was added. Instead of calling: CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, /* isVolatile */ false) you now call CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, SrcAlign, /* isVolatile */ false) There is a temporary class (IntegerAlignment) which takes the source alignment and rejects implicit conversion from bool. This is to prevent isVolatile here from passing its default parameter to the source alignment. Note, changes in future can now be made to codegen. I didn't change anything here, but this change should enable better memcpy code sequences. Reviewed by Hal Finkel. llvm-svn: 253511
2015-11-19 06:17:24 +08:00
if (ClPreserveAlignment) {
AlignShadow = IRB.CreateMul(I.getAlignmentCst(),
ConstantInt::get(I.getAlignmentCst()->getType(),
DFSF.DFS.ShadowWidth / 8));
Change memcpy/memset/memmove to have dest and source alignments. Note, this was reviewed (and more details are in) http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html These intrinsics currently have an explicit alignment argument which is required to be a constant integer. It represents the alignment of the source and dest, and so must be the minimum of those. This change allows source and dest to each have their own alignments by using the alignment attribute on their arguments. The alignment argument itself is removed. There are a few places in the code for which the code needs to be checked by an expert as to whether using only src/dest alignment is safe. For those places, they currently take the minimum of src/dest alignments which matches the current behaviour. For example, code which used to read: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 500, i32 8, i1 false) will now read: call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 8 %dest, i8* align 8 %src, i32 500, i1 false) For out of tree owners, I was able to strip alignment from calls using sed by replacing: (call.*llvm\.memset.*)i32\ [0-9]*\,\ i1 false\) with: $1i1 false) and similarly for memmove and memcpy. I then added back in alignment to test cases which needed it. A similar commit will be made to clang which actually has many differences in alignment as now IRBuilder can generate different source/dest alignments on calls. In IRBuilder itself, a new argument was added. Instead of calling: CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, /* isVolatile */ false) you now call CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, SrcAlign, /* isVolatile */ false) There is a temporary class (IntegerAlignment) which takes the source alignment and rejects implicit conversion from bool. This is to prevent isVolatile here from passing its default parameter to the source alignment. Note, changes in future can now be made to codegen. I didn't change anything here, but this change should enable better memcpy code sequences. Reviewed by Hal Finkel. llvm-svn: 253511
2015-11-19 06:17:24 +08:00
} else {
AlignShadow = ConstantInt::get(I.getAlignmentCst()->getType(),
DFSF.DFS.ShadowWidth / 8);
Change memcpy/memset/memmove to have dest and source alignments. Note, this was reviewed (and more details are in) http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html These intrinsics currently have an explicit alignment argument which is required to be a constant integer. It represents the alignment of the source and dest, and so must be the minimum of those. This change allows source and dest to each have their own alignments by using the alignment attribute on their arguments. The alignment argument itself is removed. There are a few places in the code for which the code needs to be checked by an expert as to whether using only src/dest alignment is safe. For those places, they currently take the minimum of src/dest alignments which matches the current behaviour. For example, code which used to read: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 500, i32 8, i1 false) will now read: call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 8 %dest, i8* align 8 %src, i32 500, i1 false) For out of tree owners, I was able to strip alignment from calls using sed by replacing: (call.*llvm\.memset.*)i32\ [0-9]*\,\ i1 false\) with: $1i1 false) and similarly for memmove and memcpy. I then added back in alignment to test cases which needed it. A similar commit will be made to clang which actually has many differences in alignment as now IRBuilder can generate different source/dest alignments on calls. In IRBuilder itself, a new argument was added. Instead of calling: CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, /* isVolatile */ false) you now call CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, SrcAlign, /* isVolatile */ false) There is a temporary class (IntegerAlignment) which takes the source alignment and rejects implicit conversion from bool. This is to prevent isVolatile here from passing its default parameter to the source alignment. Note, changes in future can now be made to codegen. I didn't change anything here, but this change should enable better memcpy code sequences. Reviewed by Hal Finkel. llvm-svn: 253511
2015-11-19 06:17:24 +08:00
}
Type *Int8Ptr = Type::getInt8PtrTy(*DFSF.DFS.Ctx);
DestShadow = IRB.CreateBitCast(DestShadow, Int8Ptr);
SrcShadow = IRB.CreateBitCast(SrcShadow, Int8Ptr);
IRB.CreateCall(I.getCalledValue(), {DestShadow, SrcShadow, LenShadow,
AlignShadow, I.getVolatileCst()});
}
void DFSanVisitor::visitReturnInst(ReturnInst &RI) {
if (!DFSF.IsNativeABI && RI.getReturnValue()) {
switch (DFSF.IA) {
case DataFlowSanitizer::IA_TLS: {
Value *S = DFSF.getShadow(RI.getReturnValue());
IRBuilder<> IRB(&RI);
IRB.CreateStore(S, DFSF.getRetvalTLS());
break;
}
case DataFlowSanitizer::IA_Args: {
IRBuilder<> IRB(&RI);
Type *RT = DFSF.F->getFunctionType()->getReturnType();
Value *InsVal =
IRB.CreateInsertValue(UndefValue::get(RT), RI.getReturnValue(), 0);
Value *InsShadow =
IRB.CreateInsertValue(InsVal, DFSF.getShadow(RI.getReturnValue()), 1);
RI.setOperand(0, InsShadow);
break;
}
}
}
}
void DFSanVisitor::visitCallSite(CallSite CS) {
Function *F = CS.getCalledFunction();
if ((F && F->isIntrinsic()) || isa<InlineAsm>(CS.getCalledValue())) {
visitOperandShadowInst(*CS.getInstruction());
return;
}
// Calls to this function are synthesized in wrappers, and we shouldn't
// instrument them.
if (F == DFSF.DFS.DFSanVarargWrapperFn)
return;
IRBuilder<> IRB(CS.getInstruction());
DenseMap<Value *, Function *>::iterator i =
DFSF.DFS.UnwrappedFnMap.find(CS.getCalledValue());
if (i != DFSF.DFS.UnwrappedFnMap.end()) {
Function *F = i->second;
switch (DFSF.DFS.getWrapperKind(F)) {
case DataFlowSanitizer::WK_Warning: {
CS.setCalledFunction(F);
IRB.CreateCall(DFSF.DFS.DFSanUnimplementedFn,
IRB.CreateGlobalStringPtr(F->getName()));
DFSF.setShadow(CS.getInstruction(), DFSF.DFS.ZeroShadow);
return;
}
case DataFlowSanitizer::WK_Discard: {
CS.setCalledFunction(F);
DFSF.setShadow(CS.getInstruction(), DFSF.DFS.ZeroShadow);
return;
}
case DataFlowSanitizer::WK_Functional: {
CS.setCalledFunction(F);
visitOperandShadowInst(*CS.getInstruction());
return;
}
case DataFlowSanitizer::WK_Custom: {
// Don't try to handle invokes of custom functions, it's too complicated.
// Instead, invoke the dfsw$ wrapper, which will in turn call the __dfsw_
// wrapper.
if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) {
FunctionType *FT = F->getFunctionType();
FunctionType *CustomFT = DFSF.DFS.getCustomFunctionType(FT);
std::string CustomFName = "__dfsw_";
CustomFName += F->getName();
Constant *CustomF =
DFSF.DFS.Mod->getOrInsertFunction(CustomFName, CustomFT);
if (Function *CustomFn = dyn_cast<Function>(CustomF)) {
CustomFn->copyAttributesFrom(F);
// Custom functions returning non-void will write to the return label.
if (!FT->getReturnType()->isVoidTy()) {
CustomFn->removeAttributes(AttributeList::FunctionIndex,
DFSF.DFS.ReadOnlyNoneAttrs);
}
}
std::vector<Value *> Args;
CallSite::arg_iterator i = CS.arg_begin();
for (unsigned n = FT->getNumParams(); n != 0; ++i, --n) {
Type *T = (*i)->getType();
FunctionType *ParamFT;
if (isa<PointerType>(T) &&
(ParamFT = dyn_cast<FunctionType>(
cast<PointerType>(T)->getElementType()))) {
std::string TName = "dfst";
TName += utostr(FT->getNumParams() - n);
TName += "$";
TName += F->getName();
Constant *T = DFSF.DFS.getOrBuildTrampolineFunction(ParamFT, TName);
Args.push_back(T);
Args.push_back(
IRB.CreateBitCast(*i, Type::getInt8PtrTy(*DFSF.DFS.Ctx)));
} else {
Args.push_back(*i);
}
}
i = CS.arg_begin();
for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
Args.push_back(DFSF.getShadow(*i));
if (FT->isVarArg()) {
auto *LabelVATy = ArrayType::get(DFSF.DFS.ShadowTy,
CS.arg_size() - FT->getNumParams());
auto *LabelVAAlloca = new AllocaInst(
LabelVATy, getDataLayout().getAllocaAddrSpace(),
"labelva", &DFSF.F->getEntryBlock().front());
for (unsigned n = 0; i != CS.arg_end(); ++i, ++n) {
auto LabelVAPtr = IRB.CreateStructGEP(LabelVATy, LabelVAAlloca, n);
IRB.CreateStore(DFSF.getShadow(*i), LabelVAPtr);
}
Args.push_back(IRB.CreateStructGEP(LabelVATy, LabelVAAlloca, 0));
}
if (!FT->getReturnType()->isVoidTy()) {
if (!DFSF.LabelReturnAlloca) {
DFSF.LabelReturnAlloca =
new AllocaInst(DFSF.DFS.ShadowTy,
getDataLayout().getAllocaAddrSpace(),
"labelreturn", &DFSF.F->getEntryBlock().front());
}
Args.push_back(DFSF.LabelReturnAlloca);
}
for (i = CS.arg_begin() + FT->getNumParams(); i != CS.arg_end(); ++i)
Args.push_back(*i);
CallInst *CustomCI = IRB.CreateCall(CustomF, Args);
CustomCI->setCallingConv(CI->getCallingConv());
CustomCI->setAttributes(CI->getAttributes());
if (!FT->getReturnType()->isVoidTy()) {
LoadInst *LabelLoad = IRB.CreateLoad(DFSF.LabelReturnAlloca);
DFSF.setShadow(CustomCI, LabelLoad);
}
CI->replaceAllUsesWith(CustomCI);
CI->eraseFromParent();
return;
}
break;
}
}
}
FunctionType *FT = cast<FunctionType>(
CS.getCalledValue()->getType()->getPointerElementType());
if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_TLS) {
for (unsigned i = 0, n = FT->getNumParams(); i != n; ++i) {
IRB.CreateStore(DFSF.getShadow(CS.getArgument(i)),
DFSF.getArgTLS(i, CS.getInstruction()));
}
}
Instruction *Next = nullptr;
if (!CS.getType()->isVoidTy()) {
if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
if (II->getNormalDest()->getSinglePredecessor()) {
Next = &II->getNormalDest()->front();
} else {
BasicBlock *NewBB =
SplitEdge(II->getParent(), II->getNormalDest(), &DFSF.DT);
Next = &NewBB->front();
}
} else {
assert(CS->getIterator() != CS->getParent()->end());
Next = CS->getNextNode();
}
if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_TLS) {
IRBuilder<> NextIRB(Next);
LoadInst *LI = NextIRB.CreateLoad(DFSF.getRetvalTLS());
DFSF.SkipInsts.insert(LI);
DFSF.setShadow(CS.getInstruction(), LI);
DFSF.NonZeroChecks.push_back(LI);
}
}
// Do all instrumentation for IA_Args down here to defer tampering with the
// CFG in a way that SplitEdge may be able to detect.
if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_Args) {
FunctionType *NewFT = DFSF.DFS.getArgsFunctionType(FT);
Value *Func =
IRB.CreateBitCast(CS.getCalledValue(), PointerType::getUnqual(NewFT));
std::vector<Value *> Args;
CallSite::arg_iterator i = CS.arg_begin(), e = CS.arg_end();
for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
Args.push_back(*i);
i = CS.arg_begin();
for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
Args.push_back(DFSF.getShadow(*i));
if (FT->isVarArg()) {
unsigned VarArgSize = CS.arg_size() - FT->getNumParams();
ArrayType *VarArgArrayTy = ArrayType::get(DFSF.DFS.ShadowTy, VarArgSize);
AllocaInst *VarArgShadow =
new AllocaInst(VarArgArrayTy, getDataLayout().getAllocaAddrSpace(),
"", &DFSF.F->getEntryBlock().front());
Args.push_back(IRB.CreateConstGEP2_32(VarArgArrayTy, VarArgShadow, 0, 0));
for (unsigned n = 0; i != e; ++i, ++n) {
IRB.CreateStore(
DFSF.getShadow(*i),
IRB.CreateConstGEP2_32(VarArgArrayTy, VarArgShadow, 0, n));
Args.push_back(*i);
}
}
CallSite NewCS;
if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
NewCS = IRB.CreateInvoke(Func, II->getNormalDest(), II->getUnwindDest(),
Args);
} else {
NewCS = IRB.CreateCall(Func, Args);
}
NewCS.setCallingConv(CS.getCallingConv());
NewCS.setAttributes(CS.getAttributes().removeAttributes(
*DFSF.DFS.Ctx, AttributeList::ReturnIndex,
AttributeFuncs::typeIncompatible(NewCS.getInstruction()->getType())));
if (Next) {
ExtractValueInst *ExVal =
ExtractValueInst::Create(NewCS.getInstruction(), 0, "", Next);
DFSF.SkipInsts.insert(ExVal);
ExtractValueInst *ExShadow =
ExtractValueInst::Create(NewCS.getInstruction(), 1, "", Next);
DFSF.SkipInsts.insert(ExShadow);
DFSF.setShadow(ExVal, ExShadow);
DFSF.NonZeroChecks.push_back(ExShadow);
CS.getInstruction()->replaceAllUsesWith(ExVal);
}
CS.getInstruction()->eraseFromParent();
}
}
void DFSanVisitor::visitPHINode(PHINode &PN) {
PHINode *ShadowPN =
PHINode::Create(DFSF.DFS.ShadowTy, PN.getNumIncomingValues(), "", &PN);
// Give the shadow phi node valid predecessors to fool SplitEdge into working.
Value *UndefShadow = UndefValue::get(DFSF.DFS.ShadowTy);
for (PHINode::block_iterator i = PN.block_begin(), e = PN.block_end(); i != e;
++i) {
ShadowPN->addIncoming(UndefShadow, *i);
}
DFSF.PHIFixups.push_back(std::make_pair(&PN, ShadowPN));
DFSF.setShadow(&PN, ShadowPN);
}