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 and variables in the input module. 11 // If the function or variable is not in the list of external names given to 12 // the pass it is marked as internal. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #define DEBUG_TYPE "internalize" 17 #include "llvm/Transforms/IPO.h" 18 #include "llvm/ADT/Statistic.h" 19 #include "llvm/Analysis/CallGraph.h" 20 #include "llvm/IR/Module.h" 21 #include "llvm/Pass.h" 22 #include "llvm/Support/CommandLine.h" 23 #include "llvm/Support/Debug.h" 24 #include "llvm/Support/raw_ostream.h" 25 #include <fstream> 26 #include <set> 27 using namespace llvm; 28 29 STATISTIC(NumAliases , "Number of aliases internalized"); 30 STATISTIC(NumFunctions, "Number of functions internalized"); 31 STATISTIC(NumGlobals , "Number of global vars internalized"); 32 33 // APIFile - A file which contains a list of symbols that should not be marked 34 // external. 35 static cl::opt<std::string> 36 APIFile("internalize-public-api-file", cl::value_desc("filename"), 37 cl::desc("A file containing list of symbol names to preserve")); 38 39 // APIList - A list of symbols that should not be marked internal. 40 static cl::list<std::string> 41 APIList("internalize-public-api-list", cl::value_desc("list"), 42 cl::desc("A list of symbol names to preserve"), 43 cl::CommaSeparated); 44 45 namespace { 46 class InternalizePass : public ModulePass { 47 std::set<std::string> ExternalNames; 48 public: 49 static char ID; // Pass identification, replacement for typeid 50 explicit InternalizePass(); 51 explicit InternalizePass(ArrayRef<const char *> exportList); 52 void LoadFile(const char *Filename); 53 void ClearExportList(); 54 void AddToExportList(const std::string &val); 55 virtual bool runOnModule(Module &M); 56 57 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 58 AU.setPreservesCFG(); 59 AU.addPreserved<CallGraph>(); 60 } 61 }; 62 } // end anonymous namespace 63 64 char InternalizePass::ID = 0; 65 INITIALIZE_PASS(InternalizePass, "internalize", 66 "Internalize Global Symbols", false, false) 67 68 InternalizePass::InternalizePass() 69 : ModulePass(ID) { 70 initializeInternalizePassPass(*PassRegistry::getPassRegistry()); 71 if (!APIFile.empty()) // If a filename is specified, use it. 72 LoadFile(APIFile.c_str()); 73 if (!APIList.empty()) // If a list is specified, use it as well. 74 ExternalNames.insert(APIList.begin(), APIList.end()); 75 } 76 77 InternalizePass::InternalizePass(ArrayRef<const char *> exportList) 78 : ModulePass(ID){ 79 initializeInternalizePassPass(*PassRegistry::getPassRegistry()); 80 for(ArrayRef<const char *>::const_iterator itr = exportList.begin(); 81 itr != exportList.end(); itr++) { 82 ExternalNames.insert(*itr); 83 } 84 } 85 86 void InternalizePass::LoadFile(const char *Filename) { 87 // Load the APIFile... 88 std::ifstream In(Filename); 89 if (!In.good()) { 90 errs() << "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 } 101 102 void InternalizePass::ClearExportList() { 103 ExternalNames.clear(); 104 } 105 106 void InternalizePass::AddToExportList(const std::string &val) { 107 ExternalNames.insert(val); 108 } 109 110 bool InternalizePass::runOnModule(Module &M) { 111 CallGraph *CG = getAnalysisIfAvailable<CallGraph>(); 112 CallGraphNode *ExternalNode = CG ? CG->getExternalCallingNode() : 0; 113 bool Changed = false; 114 115 // Never internalize functions which code-gen might insert. 116 // FIXME: We should probably add this (and the __stack_chk_guard) via some 117 // type of call-back in CodeGen. 118 ExternalNames.insert("__stack_chk_fail"); 119 120 // Mark all functions not in the api as internal. 121 // FIXME: maybe use private linkage? 122 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) 123 if (!I->isDeclaration() && // Function must be defined here 124 // Available externally is really just a "declaration with a body". 125 !I->hasAvailableExternallyLinkage() && 126 !I->hasLocalLinkage() && // Can't already have internal linkage 127 !ExternalNames.count(I->getName())) {// Not marked to keep external? 128 I->setLinkage(GlobalValue::InternalLinkage); 129 // Remove a callgraph edge from the external node to this function. 130 if (ExternalNode) ExternalNode->removeOneAbstractEdgeTo((*CG)[I]); 131 Changed = true; 132 ++NumFunctions; 133 DEBUG(dbgs() << "Internalizing func " << I->getName() << "\n"); 134 } 135 136 // Never internalize the llvm.used symbol. It is used to implement 137 // attribute((used)). 138 // FIXME: Shouldn't this just filter on llvm.metadata section?? 139 ExternalNames.insert("llvm.used"); 140 ExternalNames.insert("llvm.compiler.used"); 141 142 // Never internalize anchors used by the machine module info, else the info 143 // won't find them. (see MachineModuleInfo.) 144 ExternalNames.insert("llvm.global_ctors"); 145 ExternalNames.insert("llvm.global_dtors"); 146 ExternalNames.insert("llvm.global.annotations"); 147 148 // Never internalize symbols code-gen inserts. 149 ExternalNames.insert("__stack_chk_guard"); 150 151 // Mark all global variables with initializers that are not in the api as 152 // internal as well. 153 // FIXME: maybe use private linkage? 154 for (Module::global_iterator I = M.global_begin(), E = M.global_end(); 155 I != E; ++I) 156 if (!I->isDeclaration() && !I->hasLocalLinkage() && 157 // Available externally is really just a "declaration with a body". 158 !I->hasAvailableExternallyLinkage() && 159 !ExternalNames.count(I->getName())) { 160 I->setLinkage(GlobalValue::InternalLinkage); 161 Changed = true; 162 ++NumGlobals; 163 DEBUG(dbgs() << "Internalized gvar " << I->getName() << "\n"); 164 } 165 166 // Mark all aliases that are not in the api as internal as well. 167 for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end(); 168 I != E; ++I) 169 if (!I->isDeclaration() && !I->hasInternalLinkage() && 170 // Available externally is really just a "declaration with a body". 171 !I->hasAvailableExternallyLinkage() && 172 !ExternalNames.count(I->getName())) { 173 I->setLinkage(GlobalValue::InternalLinkage); 174 Changed = true; 175 ++NumAliases; 176 DEBUG(dbgs() << "Internalized alias " << I->getName() << "\n"); 177 } 178 179 return Changed; 180 } 181 182 ModulePass *llvm::createInternalizePass() { 183 return new InternalizePass(); 184 } 185 186 ModulePass *llvm::createInternalizePass(ArrayRef<const char *> el) { 187 return new InternalizePass(el); 188 } 189
