ExtractGV.cpp revision 212904
1//===-- ExtractGV.cpp - Global Value extraction pass ----------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This pass extracts global values 11// 12//===----------------------------------------------------------------------===// 13 14#include "llvm/Instructions.h" 15#include "llvm/LLVMContext.h" 16#include "llvm/Module.h" 17#include "llvm/Pass.h" 18#include "llvm/Constants.h" 19#include "llvm/Transforms/IPO.h" 20#include "llvm/ADT/SetVector.h" 21#include <algorithm> 22using namespace llvm; 23 24namespace { 25 /// @brief A pass to extract specific functions and their dependencies. 26 class GVExtractorPass : public ModulePass { 27 SetVector<GlobalValue *> Named; 28 bool deleteStuff; 29 public: 30 static char ID; // Pass identification, replacement for typeid 31 32 /// FunctionExtractorPass - If deleteFn is true, this pass deletes as the 33 /// specified function. Otherwise, it deletes as much of the module as 34 /// possible, except for the function specified. 35 /// 36 explicit GVExtractorPass(std::vector<GlobalValue*>& GVs, bool deleteS = true) 37 : ModulePass(ID), Named(GVs.begin(), GVs.end()), deleteStuff(deleteS) {} 38 39 bool runOnModule(Module &M) { 40 // Visit the global inline asm. 41 if (!deleteStuff) 42 M.setModuleInlineAsm(""); 43 44 // For simplicity, just give all GlobalValues ExternalLinkage. A trickier 45 // implementation could figure out which GlobalValues are actually 46 // referenced by the Named set, and which GlobalValues in the rest of 47 // the module are referenced by the NamedSet, and get away with leaving 48 // more internal and private things internal and private. But for now, 49 // be conservative and simple. 50 51 // Visit the GlobalVariables. 52 for (Module::global_iterator I = M.global_begin(), E = M.global_end(); 53 I != E; ++I) 54 if (!I->isDeclaration()) { 55 if (I->hasLocalLinkage()) 56 I->setVisibility(GlobalValue::HiddenVisibility); 57 I->setLinkage(GlobalValue::ExternalLinkage); 58 if (deleteStuff == Named.count(I)) 59 I->setInitializer(0); 60 } 61 62 // Visit the Functions. 63 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) 64 if (!I->isDeclaration()) { 65 if (I->hasLocalLinkage()) 66 I->setVisibility(GlobalValue::HiddenVisibility); 67 I->setLinkage(GlobalValue::ExternalLinkage); 68 if (deleteStuff == Named.count(I)) 69 I->deleteBody(); 70 } 71 72 return true; 73 } 74 }; 75 76 char GVExtractorPass::ID = 0; 77} 78 79ModulePass *llvm::createGVExtractionPass(std::vector<GlobalValue*>& GVs, 80 bool deleteFn) { 81 return new GVExtractorPass(GVs, deleteFn); 82} 83