77 changes: 73 additions & 4 deletions llvm/tools/llvm-objcopy/llvm-objcopy.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/Object/Archive.h"
#include "llvm/Object/ArchiveWriter.h"
#include "llvm/Object/Binary.h"
Expand All @@ -29,6 +30,7 @@
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Compression.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ErrorOr.h"
Expand Down Expand Up @@ -176,6 +178,7 @@ struct CopyConfig {
bool StripSections = false;
bool StripUnneeded = false;
bool Weaken = false;
DebugCompressionType CompressionType = DebugCompressionType::None;
};

// Configuration for the overall invocation of this tool. When invoked as
Expand Down Expand Up @@ -298,12 +301,12 @@ static SectionRename parseRenameSectionValue(StringRef FlagValue) {
}

static bool isDebugSection(const SectionBase &Sec) {
return Sec.Name.startswith(".debug") || Sec.Name.startswith(".zdebug") ||
Sec.Name == ".gdb_index";
return StringRef(Sec.Name).startswith(".debug") ||
StringRef(Sec.Name).startswith(".zdebug") || Sec.Name == ".gdb_index";
}

static bool isDWOSection(const SectionBase &Sec) {
return Sec.Name.endswith(".dwo");
return StringRef(Sec.Name).endswith(".dwo");
}

static bool onlyKeepDWOPred(const Object &Obj, const SectionBase &Sec) {
Expand Down Expand Up @@ -413,6 +416,50 @@ static Error dumpSectionToFile(StringRef SecName, StringRef Filename,
object_error::parse_failed);
}

static bool isCompressed(const SectionBase &Section) {
const char *Magic = "ZLIB";
return StringRef(Section.Name).startswith(".zdebug") ||
(Section.OriginalData.size() > strlen(Magic) &&
!strncmp(reinterpret_cast<const char *>(Section.OriginalData.data()),
Magic, strlen(Magic))) ||
(Section.Flags & ELF::SHF_COMPRESSED);
}

static bool isCompressable(const SectionBase &Section) {
return !isCompressed(Section) && isDebugSection(Section) &&
Section.Name != ".gdb_index";
}

static void compressSections(const CopyConfig &Config, Object &Obj,
SectionPred &RemovePred) {
SmallVector<SectionBase *, 13> ToCompress;
SmallVector<RelocationSection *, 13> RelocationSections;
for (auto &Sec : Obj.sections()) {
if (RelocationSection *R = dyn_cast<RelocationSection>(&Sec)) {
if (isCompressable(*R->getSection()))
RelocationSections.push_back(R);
continue;
}

if (isCompressable(Sec))
ToCompress.push_back(&Sec);
}

for (SectionBase *S : ToCompress) {
CompressedSection &CS =
Obj.addSection<CompressedSection>(*S, Config.CompressionType);

for (RelocationSection *RS : RelocationSections) {
if (RS->getSection() == S)
RS->setSection(&CS);
}
}

RemovePred = [RemovePred](const SectionBase &Sec) {
return isCompressable(Sec) || RemovePred(Sec);
};
}

// This function handles the high level operations of GNU objcopy including
// handling command line options. It's important to outline certain properties
// we expect to hold of the command line operations. Any operation that "keeps"
Expand Down Expand Up @@ -572,7 +619,7 @@ static void handleArgs(const CopyConfig &Config, Object &Obj,
return true;
if (&Sec == Obj.SectionNames)
return false;
if (Sec.Name.startswith(".gnu.warning"))
if (StringRef(Sec.Name).startswith(".gnu.warning"))
return false;
return (Sec.Flags & SHF_ALLOC) == 0;
};
Expand Down Expand Up @@ -624,6 +671,9 @@ static void handleArgs(const CopyConfig &Config, Object &Obj,
};
}

if (Config.CompressionType != DebugCompressionType::None)
compressSections(Config, Obj, RemovePred);

Obj.removeSections(RemovePred);

if (!Config.SectionsToRename.empty()) {
Expand Down Expand Up @@ -868,6 +918,25 @@ static DriverConfig parseObjcopyOptions(ArrayRef<const char *> ArgsArr) {
Config.BinaryArch = getMachineInfo(BinaryArch);
}

if (auto Arg = InputArgs.getLastArg(OBJCOPY_compress_debug_sections,
OBJCOPY_compress_debug_sections_eq)) {
Config.CompressionType = DebugCompressionType::Z;

if (Arg->getOption().getID() == OBJCOPY_compress_debug_sections_eq) {
Config.CompressionType =
StringSwitch<DebugCompressionType>(
InputArgs.getLastArgValue(OBJCOPY_compress_debug_sections_eq))
.Case("zlib-gnu", DebugCompressionType::GNU)
.Case("zlib", DebugCompressionType::Z)
.Default(DebugCompressionType::None);
if (Config.CompressionType == DebugCompressionType::None)
error("Invalid or unsupported --compress-debug-sections format: " +
InputArgs.getLastArgValue(OBJCOPY_compress_debug_sections_eq));
if (!zlib::isAvailable())
error("LLVM was not compiled with LLVM_ENABLE_ZLIB: can not compress.");
}
}

Config.SplitDWO = InputArgs.getLastArgValue(OBJCOPY_split_dwo);
Config.AddGnuDebugLink = InputArgs.getLastArgValue(OBJCOPY_add_gnu_debuglink);
Config.SymbolsPrefix = InputArgs.getLastArgValue(OBJCOPY_prefix_symbols);
Expand Down