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//===- llvm-objcopy.cpp ---------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm-objcopy.h"
#include "Object.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/Object/Binary.h"
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/Object/ELFTypes.h"
#include "llvm/Object/Error.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/FileOutputBuffer.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cstdlib>
#include <functional>
#include <iterator>
#include <memory>
#include <string>
#include <system_error>
#include <utility>
using namespace llvm;
using namespace object;
using namespace ELF;
// The name this program was invoked as.
static StringRef ToolName;
namespace llvm {
LLVM_ATTRIBUTE_NORETURN void error(Twine Message) {
errs() << ToolName << ": " << Message << ".\n";
errs().flush();
exit(1);
}
LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, std::error_code EC) {
assert(EC);
errs() << ToolName << ": '" << File << "': " << EC.message() << ".\n";
exit(1);
}
LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, Error E) {
assert(E);
std::string Buf;
raw_string_ostream OS(Buf);
logAllUnhandledErrors(std::move(E), OS, "");
OS.flush();
errs() << ToolName << ": '" << File << "': " << Buf;
exit(1);
}
} // end namespace llvm
static cl::opt<std::string> InputFilename(cl::Positional, cl::desc("<input>"));
static cl::opt<std::string> OutputFilename(cl::Positional, cl::desc("<output>"),
cl::init("-"));
static cl::opt<std::string>
OutputFormat("O", cl::desc("Set output format to one of the following:"
"\n\tbinary"));
static cl::list<std::string> ToRemove("remove-section",
cl::desc("Remove <section>"),
cl::value_desc("section"));
static cl::alias ToRemoveA("R", cl::desc("Alias for remove-section"),
cl::aliasopt(ToRemove));
static cl::opt<bool> StripAll("strip-all",
cl::desc("Removes symbol, relocation, and debug information"));
static cl::opt<bool> StripDebug("strip-debug",
cl::desc("Removes all debug information"));
static cl::opt<bool> StripSections("strip-sections",
cl::desc("Remove all section headers"));
static cl::opt<bool> StripNonAlloc("strip-non-alloc",
cl::desc("Remove all non-allocated sections"));
static cl::opt<bool>
StripDWO("strip-dwo", cl::desc("Remove all DWARF .dwo sections from file"));
static cl::opt<bool> ExtractDWO(
"extract-dwo",
cl::desc("Remove all sections that are not DWARF .dwo sections from file"));
static cl::opt<std::string>
SplitDWO("split-dwo",
cl::desc("Equivalent to extract-dwo on the input file to "
"<dwo-file>, then strip-dwo on the input file"),
cl::value_desc("dwo-file"));
using SectionPred = std::function<bool(const SectionBase &Sec)>;
bool IsDWOSection(const SectionBase &Sec) {
return Sec.Name.endswith(".dwo");
}
template <class ELFT>
bool OnlyKeepDWOPred(const Object<ELFT> &Obj, const SectionBase &Sec) {
// We can't remove the section header string table.
if (&Sec == Obj.getSectionHeaderStrTab())
return false;
// Short of keeping the string table we want to keep everything that is a DWO
// section and remove everything else.
return !IsDWOSection(Sec);
}
template <class ELFT>
void WriteObjectFile(const Object<ELFT> &Obj, StringRef File) {
std::unique_ptr<FileOutputBuffer> Buffer;
Expected<std::unique_ptr<FileOutputBuffer>> BufferOrErr =
FileOutputBuffer::create(File, Obj.totalSize(),
FileOutputBuffer::F_executable);
handleAllErrors(BufferOrErr.takeError(), [](const ErrorInfoBase &) {
error("failed to open " + OutputFilename);
});
Buffer = std::move(*BufferOrErr);
Obj.write(*Buffer);
if (auto E = Buffer->commit())
reportError(File, errorToErrorCode(std::move(E)));
}
template <class ELFT>
void SplitDWOToFile(const ELFObjectFile<ELFT> &ObjFile, StringRef File) {
// Construct a second output file for the DWO sections.
ELFObject<ELFT> DWOFile(ObjFile);
DWOFile.removeSections([&](const SectionBase &Sec) {
return OnlyKeepDWOPred<ELFT>(DWOFile, Sec);
});
DWOFile.finalize();
WriteObjectFile(DWOFile, File);
}
template <class ELFT>
void CopyBinary(const ELFObjectFile<ELFT> &ObjFile) {
std::unique_ptr<Object<ELFT>> Obj;
if (!OutputFormat.empty() && OutputFormat != "binary")
error("invalid output format '" + OutputFormat + "'");
if (!OutputFormat.empty() && OutputFormat == "binary")
Obj = llvm::make_unique<BinaryObject<ELFT>>(ObjFile);
else
Obj = llvm::make_unique<ELFObject<ELFT>>(ObjFile);
if (!SplitDWO.empty())
SplitDWOToFile<ELFT>(ObjFile, SplitDWO.getValue());
SectionPred RemovePred = [](const SectionBase &) { return false; };
if (!ToRemove.empty()) {
RemovePred = [&](const SectionBase &Sec) {
return std::find(std::begin(ToRemove), std::end(ToRemove), Sec.Name) !=
std::end(ToRemove);
};
}
if (StripDWO || !SplitDWO.empty())
RemovePred = [RemovePred](const SectionBase &Sec) {
return IsDWOSection(Sec) || RemovePred(Sec);
};
if (ExtractDWO)
RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
return OnlyKeepDWOPred(*Obj, Sec) || RemovePred(Sec);
};
if (StripAll)
RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
if (RemovePred(Sec))
return true;
if ((Sec.Flags & SHF_ALLOC) != 0)
return false;
if (&Sec == Obj->getSectionHeaderStrTab())
return false;
switch(Sec.Type) {
case SHT_SYMTAB:
case SHT_REL:
case SHT_RELA:
case SHT_STRTAB:
return true;
}
return Sec.Name.startswith(".debug");
};
if (StripSections) {
RemovePred = [RemovePred](const SectionBase &Sec) {
return RemovePred(Sec) || (Sec.Flags & SHF_ALLOC) == 0;
};
Obj->WriteSectionHeaders = false;
}
if (StripDebug) {
RemovePred = [RemovePred](const SectionBase &Sec) {
return RemovePred(Sec) || Sec.Name.startswith(".debug");
};
}
if (StripNonAlloc)
RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
if (RemovePred(Sec))
return true;
if (&Sec == Obj->getSectionHeaderStrTab())
return false;
return (Sec.Flags & SHF_ALLOC) == 0;
};
Obj->removeSections(RemovePred);
Obj->finalize();
WriteObjectFile(*Obj, OutputFilename.getValue());
}
int main(int argc, char **argv) {
// Print a stack trace if we signal out.
sys::PrintStackTraceOnErrorSignal(argv[0]);
PrettyStackTraceProgram X(argc, argv);
llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
cl::ParseCommandLineOptions(argc, argv, "llvm objcopy utility\n");
ToolName = argv[0];
if (InputFilename.empty()) {
cl::PrintHelpMessage();
return 2;
}
Expected<OwningBinary<Binary>> BinaryOrErr = createBinary(InputFilename);
if (!BinaryOrErr)
reportError(InputFilename, BinaryOrErr.takeError());
Binary &Binary = *BinaryOrErr.get().getBinary();
if (auto *o = dyn_cast<ELFObjectFile<ELF64LE>>(&Binary)) {
CopyBinary(*o);
return 0;
}
if (auto *o = dyn_cast<ELFObjectFile<ELF32LE>>(&Binary)) {
CopyBinary(*o);
return 0;
}
if (auto *o = dyn_cast<ELFObjectFile<ELF64BE>>(&Binary)) {
CopyBinary(*o);
return 0;
}
if (auto *o = dyn_cast<ELFObjectFile<ELF32BE>>(&Binary)) {
CopyBinary(*o);
return 0;
}
reportError(InputFilename, object_error::invalid_file_type);
}
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