64 lines
2.2 KiB
C++
64 lines
2.2 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 "Utils.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(Oracle &O, Module &Program) {
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// Get GVs inside desired chunks
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std::vector<GlobalVariable *> InitGVsToKeep;
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for (auto &GV : Program.globals())
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if (O.shouldKeep())
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InitGVsToKeep.push_back(&GV);
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// We create a vector first, then convert it to a set, so that we don't have
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// to pay the cost of rebalancing the set frequently if the order we insert
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// the elements doesn't match the order they should appear inside the set.
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std::set<GlobalVariable *> GVsToKeep(InitGVsToKeep.begin(),
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InitGVsToKeep.end());
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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(getDefaultValue(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(getDefaultValue(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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void llvm::reduceGlobalsDeltaPass(TestRunner &Test) {
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runDeltaPass(Test, extractGVsFromModule, "Reducing GlobalVariables");
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}
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