forked from OSchip/llvm-project
126 lines
4.3 KiB
C++
126 lines
4.3 KiB
C++
//===- ReduceArguments.cpp - Specialized Delta Pass -----------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements a function which calls the Generic Delta pass in order
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// to reduce uninteresting Arguments from defined functions.
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//
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//===----------------------------------------------------------------------===//
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#include "ReduceArguments.h"
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#include "Delta.h"
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#include "llvm/ADT/SmallVector.h"
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#include <set>
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#include <vector>
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using namespace llvm;
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/// Goes over OldF calls and replaces them with a call to NewF
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static void replaceFunctionCalls(Function &OldF, Function &NewF,
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const std::set<int> &ArgIndexesToKeep) {
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const auto &Users = OldF.users();
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for (auto I = Users.begin(), E = Users.end(); I != E; )
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if (auto *CI = dyn_cast<CallInst>(*I++)) {
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SmallVector<Value *, 8> Args;
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for (auto ArgI = CI->arg_begin(), E = CI->arg_end(); ArgI != E; ++ArgI)
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if (ArgIndexesToKeep.count(ArgI - CI->arg_begin()))
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Args.push_back(*ArgI);
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CallInst *NewCI = CallInst::Create(&NewF, Args);
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NewCI->setCallingConv(NewF.getCallingConv());
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if (!CI->use_empty())
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CI->replaceAllUsesWith(NewCI);
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ReplaceInstWithInst(CI, NewCI);
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}
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}
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/// Removes out-of-chunk arguments from functions, and modifies their calls
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/// accordingly. It also removes allocations of out-of-chunk arguments.
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static void extractArgumentsFromModule(std::vector<Chunk> ChunksToKeep,
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Module *Program) {
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int I = 0, ArgCount = 0;
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std::set<Argument *> ArgsToKeep;
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std::vector<Function *> Funcs;
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// Get inside-chunk arguments, as well as their parent function
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for (auto &F : *Program)
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if (!F.isDeclaration()) {
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Funcs.push_back(&F);
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for (auto &A : F.args())
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if (I < (int)ChunksToKeep.size()) {
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if (ChunksToKeep[I].contains(++ArgCount))
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ArgsToKeep.insert(&A);
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if (ChunksToKeep[I].end == ArgCount)
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++I;
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}
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}
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for (auto *F : Funcs) {
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ValueToValueMapTy VMap;
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std::vector<Instruction *> InstToDelete;
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for (auto &A : F->args())
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if (!ArgsToKeep.count(&A)) {
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// By adding undesired arguments to the VMap, CloneFunction will remove
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// them from the resulting Function
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VMap[&A] = UndefValue::get(A.getType());
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for (auto *U : A.users())
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if (auto *I = dyn_cast<Instruction>(*&U))
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InstToDelete.push_back(I);
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}
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// Delete any instruction that uses the argument
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for (auto *I : InstToDelete) {
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I->replaceAllUsesWith(UndefValue::get(I->getType()));
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I->eraseFromParent();
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}
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// No arguments to reduce
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if (VMap.empty())
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continue;
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std::set<int> ArgIndexesToKeep;
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int ArgI = 0;
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for (auto &Arg : F->args())
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if (ArgsToKeep.count(&Arg))
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ArgIndexesToKeep.insert(++ArgI);
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auto *ClonedFunc = CloneFunction(F, VMap);
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// In order to preserve function order, we move Clone after old Function
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ClonedFunc->removeFromParent();
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Program->getFunctionList().insertAfter(F->getIterator(), ClonedFunc);
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replaceFunctionCalls(*F, *ClonedFunc, ArgIndexesToKeep);
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// Rename Cloned Function to Old's name
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std::string FName = F->getName();
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F->eraseFromParent();
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ClonedFunc->setName(FName);
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}
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}
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/// Counts the amount of arguments in non-declaration functions and prints their
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/// respective name, index, and parent function name
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static int countArguments(Module *Program) {
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// TODO: Silence index with --quiet flag
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outs() << "----------------------------\n";
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outs() << "Param Index Reference:\n";
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int ArgsCount = 0;
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for (auto &F : *Program)
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if (!F.isDeclaration() && F.arg_size()) {
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outs() << " " << F.getName() << "\n";
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for (auto &A : F.args())
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outs() << "\t" << ++ArgsCount << ": " << A.getName() << "\n";
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outs() << "----------------------------\n";
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}
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return ArgsCount;
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}
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void llvm::reduceArgumentsDeltaPass(TestRunner &Test) {
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outs() << "*** Reducing Arguments...\n";
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int ArgCount = countArguments(Test.getProgram());
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runDeltaPass(Test, ArgCount, extractArgumentsFromModule);
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}
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