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

68 lines
2.4 KiB
C++

//===- 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 "Support/CommandLine.h"
#include <memory>
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"));
// 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) {
cl::ParseCommandLineOptions(argc, argv, " llvm extractor\n");
std::auto_ptr<Module> M(ParseBytecodeFile(InputFilename));
if (M.get() == 0) {
std::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) {
std::cerr << argv[0] << ": program doesn't contain function named '"
<< ExtractFunc << "'!\n";
return 1;
}
// In addition to just parsing the input from GCC, we also want to spiff it up
// a little bit. Do this now.
//
PassManager Passes;
Passes.add(new TargetData("extract", M.get())); // Use correct TargetData
Passes.add(createFunctionExtractionPass(F)); // Extract the function
Passes.add(createGlobalDCEPass()); // Delete unreachable globals
Passes.add(createFunctionResolvingPass()); // Delete prototypes
Passes.add(createDeadTypeEliminationPass()); // Remove dead types...
Passes.add(new WriteBytecodePass(&std::cout)); // Write bytecode to file...
Passes.run(*M.get());
return 0;
}