forked from OSchip/llvm-project
93 lines
3.1 KiB
C++
93 lines
3.1 KiB
C++
//===-- ExtractGV.cpp - Global Value extraction pass ----------------------===//
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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 pass extracts global values
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Instructions.h"
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#include "llvm/LLVMContext.h"
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#include "llvm/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/Constants.h"
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#include "llvm/Transforms/IPO.h"
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#include "llvm/ADT/SetVector.h"
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#include <algorithm>
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using namespace llvm;
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namespace {
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/// @brief A pass to extract specific functions and their dependencies.
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class GVExtractorPass : public ModulePass {
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SetVector<GlobalValue *> Named;
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bool deleteStuff;
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public:
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static char ID; // Pass identification, replacement for typeid
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/// FunctionExtractorPass - If deleteFn is true, this pass deletes as the
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/// specified function. Otherwise, it deletes as much of the module as
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/// possible, except for the function specified.
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///
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explicit GVExtractorPass(std::vector<GlobalValue*>& GVs, bool deleteS = true)
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: ModulePass(ID), Named(GVs.begin(), GVs.end()), deleteStuff(deleteS) {}
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bool runOnModule(Module &M) {
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// Visit the global inline asm.
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if (!deleteStuff)
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M.setModuleInlineAsm("");
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// For simplicity, just give all GlobalValues ExternalLinkage. A trickier
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// implementation could figure out which GlobalValues are actually
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// referenced by the Named set, and which GlobalValues in the rest of
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// the module are referenced by the NamedSet, and get away with leaving
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// more internal and private things internal and private. But for now,
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// be conservative and simple.
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// Visit the GlobalVariables.
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for (Module::global_iterator I = M.global_begin(), E = M.global_end();
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I != E; ++I) {
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if (deleteStuff == (bool)Named.count(I) && !I->isDeclaration()) {
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I->setInitializer(0);
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} else {
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if (I->hasAvailableExternallyLinkage())
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continue;
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if (I->getName() == "llvm.global_ctors")
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continue;
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}
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if (I->hasLocalLinkage())
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I->setVisibility(GlobalValue::HiddenVisibility);
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I->setLinkage(GlobalValue::ExternalLinkage);
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}
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// Visit the Functions.
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
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if (deleteStuff == (bool)Named.count(I) && !I->isDeclaration()) {
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I->deleteBody();
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} else {
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if (I->hasAvailableExternallyLinkage())
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continue;
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}
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if (I->hasLocalLinkage())
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I->setVisibility(GlobalValue::HiddenVisibility);
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I->setLinkage(GlobalValue::ExternalLinkage);
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}
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return true;
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}
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};
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char GVExtractorPass::ID = 0;
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}
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ModulePass *llvm::createGVExtractionPass(std::vector<GlobalValue*>& GVs,
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bool deleteFn) {
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return new GVExtractorPass(GVs, deleteFn);
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}
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