75 lines
2.4 KiB
C++
75 lines
2.4 KiB
C++
//===- ReduceGlobalVars.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 Global Variables in the provided Module.
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//
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//===----------------------------------------------------------------------===//
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#include "ReduceGlobalVars.h"
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#include "llvm/IR/Constants.h"
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#include <set>
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using namespace llvm;
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/// Removes all the GVs that aren't inside the desired Chunks.
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static void extractGVsFromModule(std::vector<Chunk> ChunksToKeep,
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Module *Program) {
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Oracle O(ChunksToKeep);
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// Get GVs inside desired chunks
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std::set<GlobalVariable *> GVsToKeep;
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for (auto &GV : Program->globals())
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if (O.shouldKeep())
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GVsToKeep.insert(&GV);
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// Delete out-of-chunk GVs and their uses
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std::vector<GlobalVariable *> ToRemove;
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std::vector<WeakVH> InstToRemove;
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for (auto &GV : Program->globals())
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if (!GVsToKeep.count(&GV)) {
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for (auto U : GV.users())
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if (auto *Inst = dyn_cast<Instruction>(U))
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InstToRemove.push_back(Inst);
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GV.replaceAllUsesWith(UndefValue::get(GV.getType()));
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ToRemove.push_back(&GV);
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}
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// Delete (unique) Instruction uses of unwanted GVs
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for (Value *V : InstToRemove) {
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if (!V)
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continue;
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auto *Inst = cast<Instruction>(V);
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Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
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Inst->eraseFromParent();
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}
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for (auto *GV : ToRemove)
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GV->eraseFromParent();
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}
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/// Counts the amount of GVs and displays their
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/// respective name & index
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static int countGVs(Module *Program) {
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// TODO: Silence index with --quiet flag
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outs() << "----------------------------\n";
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outs() << "GlobalVariable Index Reference:\n";
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int GVCount = 0;
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for (auto &GV : Program->globals())
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outs() << "\t" << ++GVCount << ": " << GV.getName() << "\n";
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outs() << "----------------------------\n";
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return GVCount;
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}
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void llvm::reduceGlobalsDeltaPass(TestRunner &Test) {
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outs() << "*** Reducing GVs...\n";
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int GVCount = countGVs(Test.getProgram());
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runDeltaPass(Test, GVCount, extractGVsFromModule);
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}
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