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