#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCValue.h"
+#include "llvm/Support/Compression.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/ELF.h"
void CreateRelocationSections(MCAssembler &Asm, MCAsmLayout &Layout,
RelMapTy &RelMap);
+ void CompressDebugSections(MCAssembler &Asm, MCAsmLayout &Layout);
+
void WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout,
const RelMapTy &RelMap);
}
}
+static SmallVector<char, 128> getUncompressedData(MCAsmLayout &Layout, MCSectionData::FragmentListType &Fragments) {
+ SmallVector<char, 128> UncompressedData;
+ for (const MCFragment &F : Fragments) {
+ const SmallVectorImpl<char> *Contents;
+ switch (F.getKind()) {
+ case MCFragment::FT_Data:
+ Contents = &cast<MCDataFragment>(F).getContents();
+ break;
+ case MCFragment::FT_Dwarf:
+ Contents = &cast<MCDwarfLineAddrFragment>(F).getContents();
+ break;
+ case MCFragment::FT_DwarfFrame:
+ Contents = &cast<MCDwarfCallFrameFragment>(F).getContents();
+ break;
+ default:
+ llvm_unreachable(
+ "Not expecting any other fragment types in a debug_* section");
+ }
+ UncompressedData.append(Contents->begin(), Contents->end());
+ }
+ return UncompressedData;
+}
+
+// Include the debug info compression header:
+// "ZLIB" followed by 8 bytes representing the uncompressed size of the section,
+// useful for consumers to preallocate a buffer to decompress into.
+static void prependCompressionHeader(uint64_t Size, SmallVectorImpl<char> &CompressedContents) {
+ static const StringRef Magic = "ZLIB";
+ if (sys::IsLittleEndianHost)
+ Size = sys::SwapByteOrder(Size);
+ CompressedContents.insert(CompressedContents.begin(),
+ Magic.size() + sizeof(Size), 0);
+ std::copy(Magic.begin(), Magic.end(), CompressedContents.begin());
+ std::copy(reinterpret_cast<char *>(&Size),
+ reinterpret_cast<char *>(&Size + 1),
+ CompressedContents.begin() + Magic.size());
+}
+
+// Return a single fragment containing the compressed contents of the whole
+// section. Null if the section was not compressed for any reason.
+static std::unique_ptr<MCDataFragment> getCompressedFragment(MCAsmLayout &Layout, MCSectionData::FragmentListType &Fragments) {
+ std::unique_ptr<MCDataFragment> CompressedFragment(new MCDataFragment());
+
+ // Gather the uncompressed data from all the fragments, recording the
+ // alignment fragment, if seen, and any fixups.
+ SmallVector<char, 128> UncompressedData =
+ getUncompressedData(Layout, Fragments);
+
+ SmallVectorImpl<char> &CompressedContents = CompressedFragment->getContents();
+
+ zlib::Status Success = zlib::compress(
+ StringRef(UncompressedData.data(), UncompressedData.size()),
+ CompressedContents);
+ if (Success != zlib::StatusOK)
+ return nullptr;
+
+ prependCompressionHeader(UncompressedData.size(), CompressedContents);
+
+ return CompressedFragment;
+}
+
+static void CompressDebugSection(MCAssembler &Asm, MCAsmLayout &Layout,
+ const MCSectionELF &Section,
+ MCSectionData &SD) {
+ StringRef SectionName = Section.getSectionName();
+ MCSectionData::FragmentListType &Fragments = SD.getFragmentList();
+
+ std::unique_ptr<MCDataFragment> CompressedFragment =
+ getCompressedFragment(Layout, Fragments);
+
+ // Leave the section as-is if the fragments could not be compressed.
+ if (!CompressedFragment)
+ return;
+
+ // Invalidate the layout for the whole section since it will have new and
+ // different fragments now.
+ Layout.invalidateFragmentsFrom(&Fragments.front());
+ Fragments.clear();
+
+ // Complete the initialization of the new fragment
+ CompressedFragment->setParent(&SD);
+ CompressedFragment->setLayoutOrder(0);
+ Fragments.push_back(CompressedFragment.release());
+
+ // Rename from .debug_* to .zdebug_*
+ Asm.getContext().renameELFSection(&Section,
+ (".z" + SectionName.drop_front(1)).str());
+}
+
+void ELFObjectWriter::CompressDebugSections(MCAssembler &Asm,
+ MCAsmLayout &Layout) {
+ if (!Asm.getContext().getAsmInfo()->compressDebugSections())
+ return;
+
+ for (MCSectionData &SD : Asm) {
+ const MCSectionELF &Section = static_cast<const MCSectionELF&>(SD.getSection());
+ StringRef SectionName = Section.getSectionName();
+
+ // Compressing debug_frame requires handling alignment fragments which is
+ // more work (possibly generalizing MCAssembler.cpp:writeFragment to allow
+ // for writing to arbitrary buffers) for little benefit.
+ if (!SectionName.startswith(".debug_") || SectionName == ".debug_frame")
+ continue;
+
+ CompressDebugSection(Asm, Layout, Section, SD);
+ }
+}
+
void ELFObjectWriter::WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout,
const RelMapTy &RelMap) {
for (MCAssembler::const_iterator it = Asm.begin(),
unsigned NumUserSections = Asm.size();
+ CompressDebugSections(Asm, const_cast<MCAsmLayout&>(Layout));
+
DenseMap<const MCSectionELF*, const MCSectionELF*> RelMap;
CreateRelocationSections(Asm, const_cast<MCAsmLayout&>(Layout), RelMap);
-// RUN: llvm-mc -filetype=obj -compress-debug-sections -triple x86_64-pc-linux-gnu %s -o - | llvm-objdump -s - | FileCheck %s
-
-// XFAIL: *
+// RUN: llvm-mc -filetype=obj -compress-debug-sections -triple x86_64-pc-linux-gnu %s -o %t
+// RUN: llvm-objdump -s %t | FileCheck %s
+// RUN: llvm-dwarfdump -debug-dump=abbrev %t | FileCheck --check-prefix=ABBREV %s
// REQUIRES: zlib
-// CHECK: Contents of section .debug_line:
-// FIXME: Figure out how to handle debug_line that currently uses multiple section fragments
+// CHECK: Contents of section .zdebug_line:
+// Check for the 'ZLIB' file magic at the start of the section only
+// CHECK-NEXT: ZLIB
// CHECK-NOT: ZLIB
+// CHECK: Contents of
// CHECK: Contents of section .zdebug_abbrev:
-// Check for the 'ZLIB' file magic at the start of the section
// CHECK-NEXT: ZLIB
-// We shouldn't compress the debug_frame section, since it can be relaxed
-// CHECK: Contents of section .debug_frame
+// FIXME: Handle compressing alignment fragments to support compressing debug_frame
+// CHECK: Contents of section .debug_frame:
// CHECK-NOT: ZLIB
+// CHECK: Contents of
+
+// Decompress one valid dwarf section just to check that this roundtrips
+// ABBREV: Abbrev table for offset: 0x00000000
+// ABBREV: [1] DW_TAG_compile_unit DW_CHILDREN_no
.section .debug_line,"",@progbits
.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
+ .byte 17 # DW_TAG_compile_unit
+ .byte 0 # DW_CHILDREN_no
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
.text
foo:
.cfi_startproc
projects / oota-llvm.git / commitdiff