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Diffstat (limited to 'contrib/llvm/lib/Transforms/Utils/ModuleUtils.cpp')
| -rw-r--r-- | contrib/llvm/lib/Transforms/Utils/ModuleUtils.cpp | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Transforms/Utils/ModuleUtils.cpp b/contrib/llvm/lib/Transforms/Utils/ModuleUtils.cpp new file mode 100644 index 000000000000..29d334f2968f --- /dev/null +++ b/contrib/llvm/lib/Transforms/Utils/ModuleUtils.cpp @@ -0,0 +1,271 @@ +//===-- ModuleUtils.cpp - Functions to manipulate Modules -----------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This family of functions perform manipulations on Modules. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Transforms/Utils/ModuleUtils.h" +#include "llvm/IR/DerivedTypes.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/IRBuilder.h" +#include "llvm/IR/Module.h" +#include "llvm/Support/raw_ostream.h" + +using namespace llvm; + +static void appendToGlobalArray(const char *Array, Module &M, Function *F, + int Priority, Constant *Data) { + IRBuilder<> IRB(M.getContext()); + FunctionType *FnTy = FunctionType::get(IRB.getVoidTy(), false); + + // Get the current set of static global constructors and add the new ctor + // to the list. + SmallVector<Constant *, 16> CurrentCtors; + StructType *EltTy; + if (GlobalVariable *GVCtor = M.getNamedGlobal(Array)) { + ArrayType *ATy = cast<ArrayType>(GVCtor->getValueType()); + StructType *OldEltTy = cast<StructType>(ATy->getElementType()); + // Upgrade a 2-field global array type to the new 3-field format if needed. + if (Data && OldEltTy->getNumElements() < 3) + EltTy = StructType::get(IRB.getInt32Ty(), PointerType::getUnqual(FnTy), + IRB.getInt8PtrTy(), nullptr); + else + EltTy = OldEltTy; + if (Constant *Init = GVCtor->getInitializer()) { + unsigned n = Init->getNumOperands(); + CurrentCtors.reserve(n + 1); + for (unsigned i = 0; i != n; ++i) { + auto Ctor = cast<Constant>(Init->getOperand(i)); + if (EltTy != OldEltTy) + Ctor = ConstantStruct::get( + EltTy, Ctor->getAggregateElement((unsigned)0), + Ctor->getAggregateElement(1), + Constant::getNullValue(IRB.getInt8PtrTy()), nullptr); + CurrentCtors.push_back(Ctor); + } + } + GVCtor->eraseFromParent(); + } else { + // Use the new three-field struct if there isn't one already. + EltTy = StructType::get(IRB.getInt32Ty(), PointerType::getUnqual(FnTy), + IRB.getInt8PtrTy(), nullptr); + } + + // Build a 2 or 3 field global_ctor entry. We don't take a comdat key. + Constant *CSVals[3]; + CSVals[0] = IRB.getInt32(Priority); + CSVals[1] = F; + // FIXME: Drop support for the two element form in LLVM 4.0. + if (EltTy->getNumElements() >= 3) + CSVals[2] = Data ? ConstantExpr::getPointerCast(Data, IRB.getInt8PtrTy()) + : Constant::getNullValue(IRB.getInt8PtrTy()); + Constant *RuntimeCtorInit = + ConstantStruct::get(EltTy, makeArrayRef(CSVals, EltTy->getNumElements())); + + CurrentCtors.push_back(RuntimeCtorInit); + + // Create a new initializer. + ArrayType *AT = ArrayType::get(EltTy, CurrentCtors.size()); + Constant *NewInit = ConstantArray::get(AT, CurrentCtors); + + // Create the new global variable and replace all uses of + // the old global variable with the new one. + (void)new GlobalVariable(M, NewInit->getType(), false, + GlobalValue::AppendingLinkage, NewInit, Array); +} + +void llvm::appendToGlobalCtors(Module &M, Function *F, int Priority, Constant *Data) { + appendToGlobalArray("llvm.global_ctors", M, F, Priority, Data); +} + +void llvm::appendToGlobalDtors(Module &M, Function *F, int Priority, Constant *Data) { + appendToGlobalArray("llvm.global_dtors", M, F, Priority, Data); +} + +static void appendToUsedList(Module &M, StringRef Name, ArrayRef<GlobalValue *> Values) { + GlobalVariable *GV = M.getGlobalVariable(Name); + SmallPtrSet<Constant *, 16> InitAsSet; + SmallVector<Constant *, 16> Init; + if (GV) { + ConstantArray *CA = dyn_cast<ConstantArray>(GV->getInitializer()); + for (auto &Op : CA->operands()) { + Constant *C = cast_or_null<Constant>(Op); + if (InitAsSet.insert(C).second) + Init.push_back(C); + } + GV->eraseFromParent(); + } + + Type *Int8PtrTy = llvm::Type::getInt8PtrTy(M.getContext()); + for (auto *V : Values) { + Constant *C = ConstantExpr::getBitCast(V, Int8PtrTy); + if (InitAsSet.insert(C).second) + Init.push_back(C); + } + + if (Init.empty()) + return; + + ArrayType *ATy = ArrayType::get(Int8PtrTy, Init.size()); + GV = new llvm::GlobalVariable(M, ATy, false, GlobalValue::AppendingLinkage, + ConstantArray::get(ATy, Init), Name); + GV->setSection("llvm.metadata"); +} + +void llvm::appendToUsed(Module &M, ArrayRef<GlobalValue *> Values) { + appendToUsedList(M, "llvm.used", Values); +} + +void llvm::appendToCompilerUsed(Module &M, ArrayRef<GlobalValue *> Values) { + appendToUsedList(M, "llvm.compiler.used", Values); +} + +Function *llvm::checkSanitizerInterfaceFunction(Constant *FuncOrBitcast) { + if (isa<Function>(FuncOrBitcast)) + return cast<Function>(FuncOrBitcast); + FuncOrBitcast->print(errs()); + errs() << '\n'; + std::string Err; + raw_string_ostream Stream(Err); + Stream << "Sanitizer interface function redefined: " << *FuncOrBitcast; + report_fatal_error(Err); +} + +Function *llvm::declareSanitizerInitFunction(Module &M, StringRef InitName, + ArrayRef<Type *> InitArgTypes) { + assert(!InitName.empty() && "Expected init function name"); + Function *F = checkSanitizerInterfaceFunction(M.getOrInsertFunction( + InitName, + FunctionType::get(Type::getVoidTy(M.getContext()), InitArgTypes, false), + AttributeList())); + F->setLinkage(Function::ExternalLinkage); + return F; +} + +std::pair<Function *, Function *> llvm::createSanitizerCtorAndInitFunctions( + Module &M, StringRef CtorName, StringRef InitName, + ArrayRef<Type *> InitArgTypes, ArrayRef<Value *> InitArgs, + StringRef VersionCheckName) { + assert(!InitName.empty() && "Expected init function name"); + assert(InitArgs.size() == InitArgTypes.size() && + "Sanitizer's init function expects different number of arguments"); + Function *InitFunction = + declareSanitizerInitFunction(M, InitName, InitArgTypes); + Function *Ctor = Function::Create( + FunctionType::get(Type::getVoidTy(M.getContext()), false), + GlobalValue::InternalLinkage, CtorName, &M); + BasicBlock *CtorBB = BasicBlock::Create(M.getContext(), "", Ctor); + IRBuilder<> IRB(ReturnInst::Create(M.getContext(), CtorBB)); + IRB.CreateCall(InitFunction, InitArgs); + if (!VersionCheckName.empty()) { + Function *VersionCheckFunction = + checkSanitizerInterfaceFunction(M.getOrInsertFunction( + VersionCheckName, FunctionType::get(IRB.getVoidTy(), {}, false), + AttributeList())); + IRB.CreateCall(VersionCheckFunction, {}); + } + return std::make_pair(Ctor, InitFunction); +} + +void llvm::filterDeadComdatFunctions( + Module &M, SmallVectorImpl<Function *> &DeadComdatFunctions) { + // Build a map from the comdat to the number of entries in that comdat we + // think are dead. If this fully covers the comdat group, then the entire + // group is dead. If we find another entry in the comdat group though, we'll + // have to preserve the whole group. + SmallDenseMap<Comdat *, int, 16> ComdatEntriesCovered; + for (Function *F : DeadComdatFunctions) { + Comdat *C = F->getComdat(); + assert(C && "Expected all input GVs to be in a comdat!"); + ComdatEntriesCovered[C] += 1; + } + + auto CheckComdat = [&](Comdat &C) { + auto CI = ComdatEntriesCovered.find(&C); + if (CI == ComdatEntriesCovered.end()) + return; + + // If this could have been covered by a dead entry, just subtract one to + // account for it. + if (CI->second > 0) { + CI->second -= 1; + return; + } + + // If we've already accounted for all the entries that were dead, the + // entire comdat is alive so remove it from the map. + ComdatEntriesCovered.erase(CI); + }; + + auto CheckAllComdats = [&] { + for (Function &F : M.functions()) + if (Comdat *C = F.getComdat()) { + CheckComdat(*C); + if (ComdatEntriesCovered.empty()) + return; + } + for (GlobalVariable &GV : M.globals()) + if (Comdat *C = GV.getComdat()) { + CheckComdat(*C); + if (ComdatEntriesCovered.empty()) + return; + } + for (GlobalAlias &GA : M.aliases()) + if (Comdat *C = GA.getComdat()) { + CheckComdat(*C); + if (ComdatEntriesCovered.empty()) + return; + } + }; + CheckAllComdats(); + + if (ComdatEntriesCovered.empty()) { + DeadComdatFunctions.clear(); + return; + } + + // Remove the entries that were not covering. + erase_if(DeadComdatFunctions, [&](GlobalValue *GV) { + return ComdatEntriesCovered.find(GV->getComdat()) == + ComdatEntriesCovered.end(); + }); +} + +std::string llvm::getUniqueModuleId(Module *M) { + MD5 Md5; + bool ExportsSymbols = false; + auto AddGlobal = [&](GlobalValue &GV) { + if (GV.isDeclaration() || GV.getName().startswith("llvm.") || + !GV.hasExternalLinkage()) + return; + ExportsSymbols = true; + Md5.update(GV.getName()); + Md5.update(ArrayRef<uint8_t>{0}); + }; + + for (auto &F : *M) + AddGlobal(F); + for (auto &GV : M->globals()) + AddGlobal(GV); + for (auto &GA : M->aliases()) + AddGlobal(GA); + for (auto &IF : M->ifuncs()) + AddGlobal(IF); + + if (!ExportsSymbols) + return ""; + + MD5::MD5Result R; + Md5.final(R); + + SmallString<32> Str; + MD5::stringifyResult(R, Str); + return ("$" + Str).str(); +} |