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 "Support/CommandLine.h"
20 #include "Support/Debug.h"
21 #include "Support/Statistic.h"
28 Statistic<> NumFunctions("internalize", "Number of functions internalized");
29 Statistic<> NumGlobals ("internalize", "Number of global vars internalized");
31 // APIFile - A file which contains a list of symbols that should not be marked
34 APIFile("internalize-public-api-file", cl::value_desc("filename"),
35 cl::desc("A file containing list of symbol names to preserve"));
37 // APIList - A list of symbols that should not be marked internal.
39 APIList("internalize-public-api-list", cl::value_desc("list"),
40 cl::desc("A list of symbol names to preserve"),
43 class InternalizePass : public Pass {
44 std::set<std::string> ExternalNames;
47 if (!APIFile.empty()) // If a filename is specified, use it
48 LoadFile(APIFile.c_str());
49 else // Else, if a list is specified, use it.
50 ExternalNames.insert(APIList.begin(), APIList.end());
53 void LoadFile(const char *Filename) {
54 // Load the APIFile...
55 std::ifstream In(Filename);
57 std::cerr << "WARNING: Internalize couldn't load file '" << Filename
59 return; // Do not internalize anything...
65 ExternalNames.insert(Symbol);
69 virtual bool run(Module &M) {
70 // If no list or file of symbols was specified, check to see if there is a
71 // "main" symbol defined in the module. If so, use it, otherwise do not
72 // internalize the module, it must be a library or something.
74 if (ExternalNames.empty()) {
75 Function *MainFunc = M.getMainFunction();
76 if (MainFunc == 0 || MainFunc->isExternal())
77 return false; // No main found, must be a library...
79 // Preserve main, internalize all else.
80 ExternalNames.insert(MainFunc->getName());
85 // Found a main function, mark all functions not named main as internal.
86 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
87 if (!I->isExternal() && // Function must be defined here
88 !I->hasInternalLinkage() && // Can't already have internal linkage
89 !ExternalNames.count(I->getName())) {// Not marked to keep external?
90 I->setLinkage(GlobalValue::InternalLinkage);
93 DEBUG(std::cerr << "Internalizing func " << I->getName() << "\n");
96 // Mark all global variables with initializers as internal as well...
97 for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
98 if (!I->isExternal() && !I->hasInternalLinkage() &&
99 !ExternalNames.count(I->getName())) {
100 // Special case handling of the global ctor and dtor list. When we
101 // internalize it, we mark it constant, which allows elimination of
102 // the list if it's empty.
104 if (I->hasAppendingLinkage() && (I->getName() == "llvm.global_ctors"||
105 I->getName() == "llvm.global_dtors"))
106 I->setConstant(true);
108 I->setLinkage(GlobalValue::InternalLinkage);
111 DEBUG(std::cerr << "Internalizing gvar " << I->getName() << "\n");
118 RegisterOpt<InternalizePass> X("internalize", "Internalize Global Symbols");
119 } // end anonymous namespace
121 Pass *createInternalizePass() {
122 return new InternalizePass();
125 } // End llvm namespace