llvm-project/llvm/tools/llvm-extract/llvm-extract.cpp

110 lines
3.9 KiB
C++

//===- llvm-extract.cpp - LLVM function extraction utility ----------------===//
//
// 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 utility changes the input module to only contain a single function,
// which is primarily used for debugging transformations.
//
//===----------------------------------------------------------------------===//
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Bytecode/Reader.h"
#include "llvm/Bytecode/WriteBytecodePass.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Streams.h"
#include "llvm/System/Signals.h"
#include <iostream>
#include <memory>
#include <fstream>
using namespace llvm;
// InputFilename - The filename to read from.
static cl::opt<std::string>
InputFilename(cl::Positional, cl::desc("<input bytecode file>"),
cl::init("-"), cl::value_desc("filename"));
static cl::opt<std::string>
OutputFilename("o", cl::desc("Specify output filename"),
cl::value_desc("filename"), cl::init("-"));
static cl::opt<bool>
Force("f", cl::desc("Overwrite output files"));
static cl::opt<bool>
DeleteFn("delete", cl::desc("Delete specified function from Module"));
// ExtractFunc - The function to extract from the module... defaults to main.
static cl::opt<std::string>
ExtractFunc("func", cl::desc("Specify function to extract"), cl::init("main"),
cl::value_desc("function"));
int main(int argc, char **argv) {
try {
cl::ParseCommandLineOptions(argc, argv, " llvm extractor\n");
sys::PrintStackTraceOnErrorSignal();
std::auto_ptr<Module> M(ParseBytecodeFile(InputFilename));
if (M.get() == 0) {
llvm_cerr << argv[0] << ": bytecode didn't read correctly.\n";
return 1;
}
// Figure out which function we should extract
Function *F = M.get()->getNamedFunction(ExtractFunc);
if (F == 0) {
llvm_cerr << argv[0] << ": program doesn't contain function named '"
<< ExtractFunc << "'!\n";
return 1;
}
// In addition to deleting all other functions, we also want to spiff it
// up a little bit. Do this now.
PassManager Passes;
Passes.add(new TargetData(M.get())); // Use correct TargetData
// Either isolate the function or delete it from the Module
Passes.add(createFunctionExtractionPass(F, DeleteFn));
Passes.add(createGlobalDCEPass()); // Delete unreachable globals
Passes.add(createFunctionResolvingPass()); // Delete prototypes
Passes.add(createDeadTypeEliminationPass()); // Remove dead types...
std::ostream *Out = 0;
if (OutputFilename != "-") { // Not stdout?
if (!Force && std::ifstream(OutputFilename.c_str())) {
// If force is not specified, make sure not to overwrite a file!
llvm_cerr << argv[0] << ": error opening '" << OutputFilename
<< "': file exists!\n"
<< "Use -f command line argument to force output\n";
return 1;
}
std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
std::ios::binary;
Out = new std::ofstream(OutputFilename.c_str(), io_mode);
} else { // Specified stdout
// FIXME: cout is not binary!
Out = &std::cout;
}
llvm_ostream L(*Out);
Passes.add(new WriteBytecodePass(&L)); // Write bytecode to file...
Passes.run(*M.get());
if (Out != &std::cout)
delete Out;
return 0;
} catch (const std::string& msg) {
llvm_cerr << argv[0] << ": " << msg << "\n";
} catch (...) {
llvm_cerr << argv[0] << ": Unexpected unknown exception occurred.\n";
}
return 1;
}