1 //===-- Internalize.cpp - Mark functions internal -------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
14 //===----------------------------------------------------------------------===//
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/ADT/Statistic.h"
29 STATISTIC(NumFunctions, "Number of functions internalized");
30 STATISTIC(NumGlobals , "Number of global vars internalized");
32 // APIFile - A file which contains a list of symbols that should not be marked
34 static cl::opt<std::string>
35 APIFile("internalize-public-api-file", cl::value_desc("filename"),
36 cl::desc("A file containing list of symbol names to preserve"));
38 // APIList - A list of symbols that should not be marked internal.
39 static cl::list<std::string>
40 APIList("internalize-public-api-list", cl::value_desc("list"),
41 cl::desc("A list of symbol names to preserve"),
45 class VISIBILITY_HIDDEN InternalizePass : public ModulePass {
46 std::set<std::string> ExternalNames;
47 /// If no api symbols were specified and a main function is defined,
48 /// assume the main function is the only API
51 static char ID; // Pass identification, replacement for typeid
52 explicit InternalizePass(bool AllButMain = true);
53 explicit InternalizePass(const std::vector <const char *>& exportList);
54 void LoadFile(const char *Filename);
55 virtual bool runOnModule(Module &M);
57 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
59 AU.addPreserved<CallGraph>();
62 } // end anonymous namespace
64 char InternalizePass::ID = 0;
65 static RegisterPass<InternalizePass>
66 X("internalize", "Internalize Global Symbols");
68 InternalizePass::InternalizePass(bool AllButMain)
69 : ModulePass(&ID), AllButMain(AllButMain){
70 if (!APIFile.empty()) // If a filename is specified, use it.
71 LoadFile(APIFile.c_str());
72 if (!APIList.empty()) // If a list is specified, use it as well.
73 ExternalNames.insert(APIList.begin(), APIList.end());
76 InternalizePass::InternalizePass(const std::vector<const char *>&exportList)
77 : ModulePass(&ID), AllButMain(false){
78 for(std::vector<const char *>::const_iterator itr = exportList.begin();
79 itr != exportList.end(); itr++) {
80 ExternalNames.insert(*itr);
84 void InternalizePass::LoadFile(const char *Filename) {
85 // Load the APIFile...
86 std::ifstream In(Filename);
88 cerr << "WARNING: Internalize couldn't load file '" << Filename
89 << "'! Continuing as if it's empty.\n";
90 return; // Just continue as if the file were empty
96 ExternalNames.insert(Symbol);
100 bool InternalizePass::runOnModule(Module &M) {
101 CallGraph *CG = getAnalysisToUpdate<CallGraph>();
102 CallGraphNode *ExternalNode = CG ? CG->getExternalCallingNode() : 0;
104 if (ExternalNames.empty()) {
105 // Return if we're not in 'all but main' mode and have no external api
108 // If no list or file of symbols was specified, check to see if there is a
109 // "main" symbol defined in the module. If so, use it, otherwise do not
110 // internalize the module, it must be a library or something.
112 Function *MainFunc = M.getFunction("main");
113 if (MainFunc == 0 || MainFunc->isDeclaration())
114 return false; // No main found, must be a library...
116 // Preserve main, internalize all else.
117 ExternalNames.insert(MainFunc->getName());
120 bool Changed = false;
122 // Mark all functions not in the api as internal.
123 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
124 if (!I->isDeclaration() && // Function must be defined here
125 !I->hasInternalLinkage() && // Can't already have internal linkage
126 !ExternalNames.count(I->getName())) {// Not marked to keep external?
127 I->setLinkage(GlobalValue::InternalLinkage);
128 // Remove a callgraph edge from the external node to this function.
129 if (ExternalNode) ExternalNode->removeOneAbstractEdgeTo((*CG)[I]);
132 DOUT << "Internalizing func " << I->getName() << "\n";
135 // Never internalize the llvm.used symbol. It is used to implement
136 // attribute((used)).
137 ExternalNames.insert("llvm.used");
139 // Never internalize anchors used by the machine module info, else the info
140 // won't find them. (see MachineModuleInfo.)
141 ExternalNames.insert("llvm.dbg.compile_units");
142 ExternalNames.insert("llvm.dbg.global_variables");
143 ExternalNames.insert("llvm.dbg.subprograms");
144 ExternalNames.insert("llvm.global_ctors");
145 ExternalNames.insert("llvm.global_dtors");
146 ExternalNames.insert("llvm.noinline");
147 ExternalNames.insert("llvm.global.annotations");
149 // Mark all global variables with initializers that are not in the api as
151 for (Module::global_iterator I = M.global_begin(), E = M.global_end();
153 if (!I->isDeclaration() && !I->hasInternalLinkage() &&
154 !ExternalNames.count(I->getName())) {
155 I->setLinkage(GlobalValue::InternalLinkage);
158 DOUT << "Internalized gvar " << I->getName() << "\n";
164 ModulePass *llvm::createInternalizePass(bool AllButMain) {
165 return new InternalizePass(AllButMain);
168 ModulePass *llvm::createInternalizePass(const std::vector <const char *> &el) {
169 return new InternalizePass(el);