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//===-- Internalize.cpp - Mark functions internal -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass loops over all of the functions in the input module, looking for a
// main function. If a main function is found, all other functions and all
// global variables with initializers are marked as internal.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "internalize"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Pass.h"
#include "llvm/Module.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/Statistic.h"
#include <fstream>
#include <set>
using namespace llvm;
STATISTIC(NumAliases , "Number of aliases internalized");
STATISTIC(NumFunctions, "Number of functions internalized");
STATISTIC(NumGlobals , "Number of global vars internalized");
// APIFile - A file which contains a list of symbols that should not be marked
// external.
static cl::opt<std::string>
APIFile("internalize-public-api-file", cl::value_desc("filename"),
cl::desc("A file containing list of symbol names to preserve"));
// APIList - A list of symbols that should not be marked internal.
static cl::list<std::string>
APIList("internalize-public-api-list", cl::value_desc("list"),
cl::desc("A list of symbol names to preserve"),
cl::CommaSeparated);
namespace {
class InternalizePass : public ModulePass {
std::set<std::string> ExternalNames;
/// If no api symbols were specified and a main function is defined,
/// assume the main function is the only API
bool AllButMain;
public:
static char ID; // Pass identification, replacement for typeid
explicit InternalizePass(bool AllButMain = true);
explicit InternalizePass(const std::vector <const char *>& exportList);
void LoadFile(const char *Filename);
virtual bool runOnModule(Module &M);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
AU.addPreserved<CallGraph>();
}
};
} // end anonymous namespace
char InternalizePass::ID = 0;
INITIALIZE_PASS(InternalizePass, "internalize",
"Internalize Global Symbols", false, false)
InternalizePass::InternalizePass(bool AllButMain)
: ModulePass(ID), AllButMain(AllButMain){
initializeInternalizePassPass(*PassRegistry::getPassRegistry());
if (!APIFile.empty()) // If a filename is specified, use it.
LoadFile(APIFile.c_str());
if (!APIList.empty()) // If a list is specified, use it as well.
ExternalNames.insert(APIList.begin(), APIList.end());
}
InternalizePass::InternalizePass(const std::vector<const char *>&exportList)
: ModulePass(ID), AllButMain(false){
initializeInternalizePassPass(*PassRegistry::getPassRegistry());
for(std::vector<const char *>::const_iterator itr = exportList.begin();
itr != exportList.end(); itr++) {
ExternalNames.insert(*itr);
}
}
void InternalizePass::LoadFile(const char *Filename) {
// Load the APIFile...
std::ifstream In(Filename);
if (!In.good()) {
errs() << "WARNING: Internalize couldn't load file '" << Filename
<< "'! Continuing as if it's empty.\n";
return; // Just continue as if the file were empty
}
while (In) {
std::string Symbol;
In >> Symbol;
if (!Symbol.empty())
ExternalNames.insert(Symbol);
}
}
bool InternalizePass::runOnModule(Module &M) {
CallGraph *CG = getAnalysisIfAvailable<CallGraph>();
CallGraphNode *ExternalNode = CG ? CG->getExternalCallingNode() : 0;
if (ExternalNames.empty()) {
// Return if we're not in 'all but main' mode and have no external api
if (!AllButMain)
return false;
// If no list or file of symbols was specified, check to see if there is a
// "main" symbol defined in the module. If so, use it, otherwise do not
// internalize the module, it must be a library or something.
//
Function *MainFunc = M.getFunction("main");
if (MainFunc == 0 || MainFunc->isDeclaration())
return false; // No main found, must be a library...
// Preserve main, internalize all else.
ExternalNames.insert(MainFunc->getName());
}
bool Changed = false;
// Never internalize functions which code-gen might insert.
// FIXME: We should probably add this (and the __stack_chk_guard) via some
// type of call-back in CodeGen.
ExternalNames.insert("__stack_chk_fail");
// Mark all functions not in the api as internal.
// FIXME: maybe use private linkage?
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isDeclaration() && // Function must be defined here
// Available externally is really just a "declaration with a body".
!I->hasAvailableExternallyLinkage() &&
!I->hasLocalLinkage() && // Can't already have internal linkage
!ExternalNames.count(I->getName())) {// Not marked to keep external?
I->setLinkage(GlobalValue::InternalLinkage);
// Remove a callgraph edge from the external node to this function.
if (ExternalNode) ExternalNode->removeOneAbstractEdgeTo((*CG)[I]);
Changed = true;
++NumFunctions;
DEBUG(dbgs() << "Internalizing func " << I->getName() << "\n");
}
// Never internalize the llvm.used symbol. It is used to implement
// attribute((used)).
// FIXME: Shouldn't this just filter on llvm.metadata section??
ExternalNames.insert("llvm.used");
ExternalNames.insert("llvm.compiler.used");
// Never internalize anchors used by the machine module info, else the info
// won't find them. (see MachineModuleInfo.)
ExternalNames.insert("llvm.global_ctors");
ExternalNames.insert("llvm.global_dtors");
ExternalNames.insert("llvm.global.annotations");
// Never internalize symbols code-gen inserts.
ExternalNames.insert("__stack_chk_guard");
// Mark all global variables with initializers that are not in the api as
// internal as well.
// FIXME: maybe use private linkage?
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
I != E; ++I)
if (!I->isDeclaration() && !I->hasLocalLinkage() &&
// Available externally is really just a "declaration with a body".
!I->hasAvailableExternallyLinkage() &&
!ExternalNames.count(I->getName())) {
I->setLinkage(GlobalValue::InternalLinkage);
Changed = true;
++NumGlobals;
DEBUG(dbgs() << "Internalized gvar " << I->getName() << "\n");
}
// Mark all aliases that are not in the api as internal as well.
for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end();
I != E; ++I)
if (!I->isDeclaration() && !I->hasInternalLinkage() &&
// Available externally is really just a "declaration with a body".
!I->hasAvailableExternallyLinkage() &&
!ExternalNames.count(I->getName())) {
I->setLinkage(GlobalValue::InternalLinkage);
Changed = true;
++NumAliases;
DEBUG(dbgs() << "Internalized alias " << I->getName() << "\n");
}
return Changed;
}
ModulePass *llvm::createInternalizePass(bool AllButMain) {
return new InternalizePass(AllButMain);
}
ModulePass *llvm::createInternalizePass(const std::vector <const char *> &el) {
return new InternalizePass(el);
}
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