llvm-6502/lib/Transforms/IPO/Internalize.cpp

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//===-- Internalize.cpp - Mark functions internal -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and 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.
//
//===----------------------------------------------------------------------===//
#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/ADT/Statistic.h"
#include <fstream>
#include <iostream>
#include <set>
using namespace llvm;
namespace {
Statistic<> NumFunctions("internalize", "Number of functions internalized");
Statistic<> NumGlobals ("internalize", "Number of global vars internalized");
// APIFile - A file which contains a list of symbols that should not be marked
// external.
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.
cl::list<std::string>
APIList("internalize-public-api-list", cl::value_desc("list"),
cl::desc("A list of symbol names to preserve"),
cl::CommaSeparated);
class InternalizePass : public ModulePass {
std::set<std::string> ExternalNames;
bool DontInternalize;
public:
InternalizePass(bool InternalizeEverything = true);
InternalizePass(const std::vector <const char *>& exportList);
void LoadFile(const char *Filename);
virtual bool runOnModule(Module &M);
};
RegisterPass<InternalizePass> X("internalize", "Internalize Global Symbols");
} // end anonymous namespace
InternalizePass::InternalizePass(bool InternalizeEverything)
: DontInternalize(false){
if (!APIFile.empty()) // If a filename is specified, use it
LoadFile(APIFile.c_str());
else if (!APIList.empty()) // Else, if a list is specified, use it.
ExternalNames.insert(APIList.begin(), APIList.end());
else if (!InternalizeEverything)
// Finally, if we're allowed to, internalize all but main.
DontInternalize = true;
}
InternalizePass::InternalizePass(const std::vector<const char *>&exportList)
: DontInternalize(false){
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()) {
std::cerr << "WARNING: Internalize couldn't load file '" << Filename
<< "'!\n";
return; // Do not internalize anything...
}
while (In) {
std::string Symbol;
In >> Symbol;
if (!Symbol.empty())
ExternalNames.insert(Symbol);
}
}
bool InternalizePass::runOnModule(Module &M) {
if (DontInternalize) 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.
//
if (ExternalNames.empty()) {
Function *MainFunc = M.getMainFunction();
if (MainFunc == 0 || MainFunc->isExternal())
return false; // No main found, must be a library...
// Preserve main, internalize all else.
ExternalNames.insert(MainFunc->getName());
}
bool Changed = false;
// Found a main function, mark all functions not named main as internal.
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isExternal() && // Function must be defined here
!I->hasInternalLinkage() && // Can't already have internal linkage
!ExternalNames.count(I->getName())) {// Not marked to keep external?
I->setLinkage(GlobalValue::InternalLinkage);
Changed = true;
++NumFunctions;
DEBUG(std::cerr << "Internalizing func " << I->getName() << "\n");
}
// Never internalize the llvm.used symbol. It is used to implement
// attribute((used)).
ExternalNames.insert("llvm.used");
// Never internalize anchors used by the debugger, else the debugger won't
// find them. (see MachineDebugInfo.)
ExternalNames.insert("llvm.dbg.compile_units");
ExternalNames.insert("llvm.dbg.global_variables");
ExternalNames.insert("llvm.dbg.subprograms");
// Mark all global variables with initializers as internal as well.
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
I != E; ++I)
if (!I->isExternal() && !I->hasInternalLinkage() &&
!ExternalNames.count(I->getName())) {
// Special case handling of the global ctor and dtor list. When we
// internalize it, we mark it constant, which allows elimination of
// the list if it's empty.
//
if (I->hasAppendingLinkage() && (I->getName() == "llvm.global_ctors" ||
I->getName() == "llvm.global_dtors")) {
// If the global ctors/dtors list has no uses, do not internalize it, as
// there is no __main in this program, so the asmprinter should handle
// it.
if (I->use_empty()) continue;
// Otherwise, also mark the list constant, as we know that it will not
// be mutated any longer, and the makes simple IPO xforms automatically
// better.
I->setConstant(true);
}
I->setLinkage(GlobalValue::InternalLinkage);
Changed = true;
++NumGlobals;
DEBUG(std::cerr << "Internalized gvar " << I->getName() << "\n");
}
return Changed;
}
ModulePass *llvm::createInternalizePass(bool InternalizeEverything) {
return new InternalizePass(InternalizeEverything);
}
ModulePass *llvm::createInternalizePass(const std::vector <const char *> &el) {
return new InternalizePass(el);
}