Internalize.cpp revision 005975c04c5ffc4ee07107ad60dd7d465464e6f7
1//===-- Internalize.cpp - Mark functions internal -------------------------===// 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 loops over all of the functions in the input module, looking for a 11// main function. If a main function is found, all other functions and all 12// global variables with initializers are marked as internal. 13// 14//===----------------------------------------------------------------------===// 15 16#define DEBUG_TYPE "internalize" 17#include "llvm/Analysis/CallGraph.h" 18#include "llvm/Transforms/IPO.h" 19#include "llvm/Pass.h" 20#include "llvm/Module.h" 21#include "llvm/Support/CommandLine.h" 22#include "llvm/Support/Compiler.h" 23#include "llvm/Support/Debug.h" 24#include "llvm/Support/raw_ostream.h" 25#include "llvm/ADT/Statistic.h" 26#include <fstream> 27#include <set> 28using namespace llvm; 29 30STATISTIC(NumAliases , "Number of aliases internalized"); 31STATISTIC(NumFunctions, "Number of functions internalized"); 32STATISTIC(NumGlobals , "Number of global vars internalized"); 33 34// APIFile - A file which contains a list of symbols that should not be marked 35// external. 36static cl::opt<std::string> 37APIFile("internalize-public-api-file", cl::value_desc("filename"), 38 cl::desc("A file containing list of symbol names to preserve")); 39 40// APIList - A list of symbols that should not be marked internal. 41static cl::list<std::string> 42APIList("internalize-public-api-list", cl::value_desc("list"), 43 cl::desc("A list of symbol names to preserve"), 44 cl::CommaSeparated); 45 46namespace { 47 class VISIBILITY_HIDDEN InternalizePass : public ModulePass { 48 std::set<std::string> ExternalNames; 49 /// If no api symbols were specified and a main function is defined, 50 /// assume the main function is the only API 51 bool AllButMain; 52 public: 53 static char ID; // Pass identification, replacement for typeid 54 explicit InternalizePass(bool AllButMain = true); 55 explicit InternalizePass(const std::vector <const char *>& exportList); 56 void LoadFile(const char *Filename); 57 virtual bool runOnModule(Module &M); 58 59 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 60 AU.setPreservesCFG(); 61 AU.addPreserved<CallGraph>(); 62 } 63 }; 64} // end anonymous namespace 65 66char InternalizePass::ID = 0; 67static RegisterPass<InternalizePass> 68X("internalize", "Internalize Global Symbols"); 69 70InternalizePass::InternalizePass(bool AllButMain) 71 : ModulePass(&ID), AllButMain(AllButMain){ 72 if (!APIFile.empty()) // If a filename is specified, use it. 73 LoadFile(APIFile.c_str()); 74 if (!APIList.empty()) // If a list is specified, use it as well. 75 ExternalNames.insert(APIList.begin(), APIList.end()); 76} 77 78InternalizePass::InternalizePass(const std::vector<const char *>&exportList) 79 : ModulePass(&ID), AllButMain(false){ 80 for(std::vector<const char *>::const_iterator itr = exportList.begin(); 81 itr != exportList.end(); itr++) { 82 ExternalNames.insert(*itr); 83 } 84} 85 86void InternalizePass::LoadFile(const char *Filename) { 87 // Load the APIFile... 88 std::ifstream In(Filename); 89 if (!In.good()) { 90 cerr << "WARNING: Internalize couldn't load file '" << Filename 91 << "'! Continuing as if it's empty.\n"; 92 return; // Just continue as if the file were empty 93 } 94 while (In) { 95 std::string Symbol; 96 In >> Symbol; 97 if (!Symbol.empty()) 98 ExternalNames.insert(Symbol); 99 } 100} 101 102bool InternalizePass::runOnModule(Module &M) { 103 CallGraph *CG = getAnalysisIfAvailable<CallGraph>(); 104 CallGraphNode *ExternalNode = CG ? CG->getExternalCallingNode() : 0; 105 106 if (ExternalNames.empty()) { 107 // Return if we're not in 'all but main' mode and have no external api 108 if (!AllButMain) 109 return false; 110 // If no list or file of symbols was specified, check to see if there is a 111 // "main" symbol defined in the module. If so, use it, otherwise do not 112 // internalize the module, it must be a library or something. 113 // 114 Function *MainFunc = M.getFunction("main"); 115 if (MainFunc == 0 || MainFunc->isDeclaration()) 116 return false; // No main found, must be a library... 117 118 // Preserve main, internalize all else. 119 ExternalNames.insert(MainFunc->getName()); 120 } 121 122 bool Changed = false; 123 124 // Mark all functions not in the api as internal. 125 // FIXME: maybe use private linkage? 126 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) 127 if (!I->isDeclaration() && // Function must be defined here 128 !I->hasLocalLinkage() && // Can't already have internal linkage 129 !ExternalNames.count(I->getName())) {// Not marked to keep external? 130 I->setLinkage(GlobalValue::InternalLinkage); 131 // Remove a callgraph edge from the external node to this function. 132 if (ExternalNode) ExternalNode->removeOneAbstractEdgeTo((*CG)[I]); 133 Changed = true; 134 ++NumFunctions; 135 DEBUG(errs() << "Internalizing func " << I->getName() << "\n"); 136 } 137 138 // Never internalize the llvm.used symbol. It is used to implement 139 // attribute((used)). 140 // FIXME: Shouldn't this just filter on llvm.metadata section?? 141 ExternalNames.insert("llvm.used"); 142 ExternalNames.insert("llvm.compiler.used"); 143 144 // Never internalize anchors used by the machine module info, else the info 145 // won't find them. (see MachineModuleInfo.) 146 ExternalNames.insert("llvm.dbg.compile_units"); 147 ExternalNames.insert("llvm.dbg.global_variables"); 148 ExternalNames.insert("llvm.dbg.subprograms"); 149 ExternalNames.insert("llvm.global_ctors"); 150 ExternalNames.insert("llvm.global_dtors"); 151 ExternalNames.insert("llvm.noinline"); 152 ExternalNames.insert("llvm.global.annotations"); 153 154 // Mark all global variables with initializers that are not in the api as 155 // internal as well. 156 // FIXME: maybe use private linkage? 157 for (Module::global_iterator I = M.global_begin(), E = M.global_end(); 158 I != E; ++I) 159 if (!I->isDeclaration() && !I->hasLocalLinkage() && 160 !ExternalNames.count(I->getName())) { 161 I->setLinkage(GlobalValue::InternalLinkage); 162 Changed = true; 163 ++NumGlobals; 164 DEBUG(errs() << "Internalized gvar " << I->getName() << "\n"); 165 } 166 167 // Mark all aliases that are not in the api as internal as well. 168 for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end(); 169 I != E; ++I) 170 if (!I->isDeclaration() && !I->hasInternalLinkage() && 171 !ExternalNames.count(I->getName())) { 172 I->setLinkage(GlobalValue::InternalLinkage); 173 Changed = true; 174 ++NumAliases; 175 DEBUG(errs() << "Internalized alias " << I->getName() << "\n"); 176 } 177 178 return Changed; 179} 180 181ModulePass *llvm::createInternalizePass(bool AllButMain) { 182 return new InternalizePass(AllButMain); 183} 184 185ModulePass *llvm::createInternalizePass(const std::vector <const char *> &el) { 186 return new InternalizePass(el); 187} 188