1 //===-- Internalize.cpp - Mark functions internal -------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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 #include "llvm/Transforms/IPO.h"
17 #include "llvm/Pass.h"
18 #include "llvm/Module.h"
19 #include "llvm/Support/CommandLine.h"
20 #include "llvm/Support/Debug.h"
21 #include "llvm/ADT/Statistic.h"
27 Statistic<> NumFunctions("internalize", "Number of functions internalized");
28 Statistic<> NumGlobals ("internalize", "Number of global vars internalized");
30 // APIFile - A file which contains a list of symbols that should not be marked
33 APIFile("internalize-public-api-file", cl::value_desc("filename"),
34 cl::desc("A file containing list of symbol names to preserve"));
36 // APIList - A list of symbols that should not be marked internal.
38 APIList("internalize-public-api-list", cl::value_desc("list"),
39 cl::desc("A list of symbol names to preserve"),
42 class InternalizePass : public ModulePass {
43 std::set<std::string> ExternalNames;
46 InternalizePass(bool InternalizeEverything = true) : DontInternalize(false){
47 if (!APIFile.empty()) // If a filename is specified, use it
48 LoadFile(APIFile.c_str());
49 else if (!APIList.empty()) // Else, if a list is specified, use it.
50 ExternalNames.insert(APIList.begin(), APIList.end());
51 else if (!InternalizeEverything)
52 // Finally, if we're allowed to, internalize all but main.
53 DontInternalize = true;
56 void LoadFile(const char *Filename) {
57 // Load the APIFile...
58 std::ifstream In(Filename);
60 std::cerr << "WARNING: Internalize couldn't load file '" << Filename
62 return; // Do not internalize anything...
68 ExternalNames.insert(Symbol);
72 virtual bool runOnModule(Module &M) {
73 if (DontInternalize) return false;
75 // If no list or file of symbols was specified, check to see if there is a
76 // "main" symbol defined in the module. If so, use it, otherwise do not
77 // internalize the module, it must be a library or something.
79 if (ExternalNames.empty()) {
80 Function *MainFunc = M.getMainFunction();
81 if (MainFunc == 0 || MainFunc->isExternal())
82 return false; // No main found, must be a library...
84 // Preserve main, internalize all else.
85 ExternalNames.insert(MainFunc->getName());
90 // Found a main function, mark all functions not named main as internal.
91 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
92 if (!I->isExternal() && // Function must be defined here
93 !I->hasInternalLinkage() && // Can't already have internal linkage
94 !ExternalNames.count(I->getName())) {// Not marked to keep external?
95 I->setLinkage(GlobalValue::InternalLinkage);
98 DEBUG(std::cerr << "Internalizing func " << I->getName() << "\n");
101 // Mark all global variables with initializers as internal as well...
102 for (Module::global_iterator I = M.global_begin(), E = M.global_end(); I != E; ++I)
103 if (!I->isExternal() && !I->hasInternalLinkage() &&
104 !ExternalNames.count(I->getName())) {
105 // Special case handling of the global ctor and dtor list. When we
106 // internalize it, we mark it constant, which allows elimination of
107 // the list if it's empty.
109 if (I->hasAppendingLinkage() && (I->getName() == "llvm.global_ctors"||
110 I->getName() == "llvm.global_dtors"))
111 I->setConstant(true);
113 I->setLinkage(GlobalValue::InternalLinkage);
116 DEBUG(std::cerr << "Internalizing gvar " << I->getName() << "\n");
123 RegisterOpt<InternalizePass> X("internalize", "Internalize Global Symbols");
124 } // end anonymous namespace
126 ModulePass *llvm::createInternalizePass(bool InternalizeEverything) {
127 return new InternalizePass(InternalizeEverything);