[llvm] r246554 - [MC] Allow MCObjectWriter's output stream to be swapped out
David Majnemer via llvm-commits
llvm-commits at lists.llvm.org
Tue Sep 1 09:19:04 PDT 2015
Author: majnemer
Date: Tue Sep 1 11:19:03 2015
New Revision: 246554
URL: http://llvm.org/viewvc/llvm-project?rev=246554&view=rev
Log:
[MC] Allow MCObjectWriter's output stream to be swapped out
There are occasions where it is useful to consider the entirety of the
contents of a section. For example, compressed debug info needs the
entire section available before it can compress it and write it out.
The compressed debug info scenario was previously implemented by
mirroring the implementation of writeSectionData in the ELFObjectWriter.
Instead, allow the output stream to be swapped on demand. This lets
callers redirect the output stream to a more convenient location before
it hits the object file.
No functionality change is intended.
Differential Revision: http://reviews.llvm.org/D12509
Modified:
llvm/trunk/include/llvm/MC/MCObjectWriter.h
llvm/trunk/lib/MC/ELFObjectWriter.cpp
llvm/trunk/lib/MC/MachObjectWriter.cpp
llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp
Modified: llvm/trunk/include/llvm/MC/MCObjectWriter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCObjectWriter.h?rev=246554&r1=246553&r2=246554&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCObjectWriter.h (original)
+++ llvm/trunk/include/llvm/MC/MCObjectWriter.h Tue Sep 1 11:19:03 2015
@@ -40,14 +40,14 @@ class MCObjectWriter {
MCObjectWriter(const MCObjectWriter &) = delete;
void operator=(const MCObjectWriter &) = delete;
-protected:
- raw_pwrite_stream &OS;
+ raw_pwrite_stream *OS;
+protected:
unsigned IsLittleEndian : 1;
protected: // Can only create subclasses.
MCObjectWriter(raw_pwrite_stream &OS, bool IsLittleEndian)
- : OS(OS), IsLittleEndian(IsLittleEndian) {}
+ : OS(&OS), IsLittleEndian(IsLittleEndian) {}
public:
virtual ~MCObjectWriter();
@@ -57,7 +57,8 @@ public:
bool isLittleEndian() const { return IsLittleEndian; }
- raw_ostream &getStream() { return OS; }
+ raw_pwrite_stream &getStream() { return *OS; }
+ void setStream(raw_pwrite_stream &NewOS) { OS = &NewOS; }
/// \name High-Level API
/// @{
@@ -113,30 +114,30 @@ public:
/// \name Binary Output
/// @{
- void write8(uint8_t Value) { OS << char(Value); }
+ void write8(uint8_t Value) { *OS << char(Value); }
void writeLE16(uint16_t Value) {
- support::endian::Writer<support::little>(OS).write(Value);
+ support::endian::Writer<support::little>(*OS).write(Value);
}
void writeLE32(uint32_t Value) {
- support::endian::Writer<support::little>(OS).write(Value);
+ support::endian::Writer<support::little>(*OS).write(Value);
}
void writeLE64(uint64_t Value) {
- support::endian::Writer<support::little>(OS).write(Value);
+ support::endian::Writer<support::little>(*OS).write(Value);
}
void writeBE16(uint16_t Value) {
- support::endian::Writer<support::big>(OS).write(Value);
+ support::endian::Writer<support::big>(*OS).write(Value);
}
void writeBE32(uint32_t Value) {
- support::endian::Writer<support::big>(OS).write(Value);
+ support::endian::Writer<support::big>(*OS).write(Value);
}
void writeBE64(uint64_t Value) {
- support::endian::Writer<support::big>(OS).write(Value);
+ support::endian::Writer<support::big>(*OS).write(Value);
}
void write16(uint16_t Value) {
@@ -164,9 +165,9 @@ public:
const char Zeros[16] = {0};
for (unsigned i = 0, e = N / 16; i != e; ++i)
- OS << StringRef(Zeros, 16);
+ *OS << StringRef(Zeros, 16);
- OS << StringRef(Zeros, N % 16);
+ *OS << StringRef(Zeros, N % 16);
}
void writeBytes(const SmallVectorImpl<char> &ByteVec,
@@ -180,7 +181,7 @@ public:
assert(
(ZeroFillSize == 0 || Str.size() <= ZeroFillSize) &&
"data size greater than fill size, unexpected large write will occur");
- OS << Str;
+ *OS << Str;
if (ZeroFillSize)
WriteZeros(ZeroFillSize - Str.size());
}
Modified: llvm/trunk/lib/MC/ELFObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/ELFObjectWriter.cpp?rev=246554&r1=246553&r2=246554&view=diff
==============================================================================
--- llvm/trunk/lib/MC/ELFObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/ELFObjectWriter.cpp Tue Sep 1 11:19:03 2015
@@ -157,9 +157,9 @@ class ELFObjectWriter : public MCObjectW
template <typename T> void write(T Val) {
if (IsLittleEndian)
- support::endian::Writer<support::little>(OS).write(Val);
+ support::endian::Writer<support::little>(getStream()).write(Val);
else
- support::endian::Writer<support::big>(OS).write(Val);
+ support::endian::Writer<support::big>(getStream()).write(Val);
}
void writeHeader(const MCAssembler &Asm);
@@ -232,7 +232,7 @@ class ELFObjectWriter : public MCObjectW
}
void ELFObjectWriter::align(unsigned Alignment) {
- uint64_t Padding = OffsetToAlignment(OS.tell(), Alignment);
+ uint64_t Padding = OffsetToAlignment(getStream().tell(), Alignment);
WriteZeros(Padding);
}
@@ -764,7 +764,7 @@ void ELFObjectWriter::computeSymbolTable
SymbolTableIndex = addToSectionTable(SymtabSection);
align(SymtabSection->getAlignment());
- uint64_t SecStart = OS.tell();
+ uint64_t SecStart = getStream().tell();
// The first entry is the undefined symbol entry.
Writer.writeSymbol(0, 0, 0, 0, 0, 0, false);
@@ -911,7 +911,7 @@ void ELFObjectWriter::computeSymbolTable
assert(MSD.Symbol->getBinding() != ELF::STB_LOCAL);
}
- uint64_t SecEnd = OS.tell();
+ uint64_t SecEnd = getStream().tell();
SectionOffsets[SymtabSection] = std::make_pair(SecStart, SecEnd);
ArrayRef<uint32_t> ShndxIndexes = Writer.getShndxIndexes();
@@ -921,12 +921,12 @@ void ELFObjectWriter::computeSymbolTable
}
assert(SymtabShndxSectionIndex != 0);
- SecStart = OS.tell();
+ SecStart = getStream().tell();
const MCSectionELF *SymtabShndxSection =
SectionTable[SymtabShndxSectionIndex - 1];
for (uint32_t Index : ShndxIndexes)
write(Index);
- SecEnd = OS.tell();
+ SecEnd = getStream().tell();
SectionOffsets[SymtabShndxSection] = std::make_pair(SecStart, SecEnd);
}
@@ -957,31 +957,6 @@ ELFObjectWriter::createRelocationSection
return RelaSection;
}
-static SmallVector<char, 128>
-getUncompressedData(const MCAsmLayout &Layout,
- const MCSection::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.
@@ -1016,27 +991,29 @@ void ELFObjectWriter::writeSectionData(c
return;
}
- // Gather the uncompressed data from all the fragments.
- const MCSection::FragmentListType &Fragments = Section.getFragmentList();
- SmallVector<char, 128> UncompressedData =
- getUncompressedData(Layout, Fragments);
+ SmallVector<char, 128> UncompressedData;
+ raw_svector_ostream VecOS(UncompressedData);
+ raw_pwrite_stream &OldStream = getStream();
+ setStream(VecOS);
+ Asm.writeSectionData(&Section, Layout);
+ setStream(OldStream);
SmallVector<char, 128> CompressedContents;
zlib::Status Success = zlib::compress(
StringRef(UncompressedData.data(), UncompressedData.size()),
CompressedContents);
if (Success != zlib::StatusOK) {
- Asm.writeSectionData(&Section, Layout);
+ getStream() << UncompressedData;
return;
}
if (!prependCompressionHeader(UncompressedData.size(), CompressedContents)) {
- Asm.writeSectionData(&Section, Layout);
+ getStream() << UncompressedData;
return;
}
Asm.getContext().renameELFSection(&Section,
(".z" + SectionName.drop_front(1)).str());
- OS << CompressedContents;
+ getStream() << CompressedContents;
}
void ELFObjectWriter::WriteSecHdrEntry(uint32_t Name, uint32_t Type,
@@ -1100,7 +1077,7 @@ void ELFObjectWriter::writeRelocations(c
const MCSectionELF *ELFObjectWriter::createStringTable(MCContext &Ctx) {
const MCSectionELF *StrtabSection = SectionTable[StringTableIndex - 1];
- OS << StrTabBuilder.data();
+ getStream() << StrTabBuilder.data();
return StrtabSection;
}
@@ -1209,12 +1186,12 @@ void ELFObjectWriter::writeObject(MCAsse
align(Section.getAlignment());
// Remember the offset into the file for this section.
- uint64_t SecStart = OS.tell();
+ uint64_t SecStart = getStream().tell();
const MCSymbolELF *SignatureSymbol = Section.getGroup();
writeSectionData(Asm, Section, Layout);
- uint64_t SecEnd = OS.tell();
+ uint64_t SecEnd = getStream().tell();
SectionOffsets[&Section] = std::make_pair(SecStart, SecEnd);
MCSectionELF *RelSection = createRelocationSection(Ctx, Section);
@@ -1246,7 +1223,7 @@ void ELFObjectWriter::writeObject(MCAsse
align(Group->getAlignment());
// Remember the offset into the file for this section.
- uint64_t SecStart = OS.tell();
+ uint64_t SecStart = getStream().tell();
const MCSymbol *SignatureSymbol = Group->getGroup();
assert(SignatureSymbol);
@@ -1256,7 +1233,7 @@ void ELFObjectWriter::writeObject(MCAsse
write(SecIndex);
}
- uint64_t SecEnd = OS.tell();
+ uint64_t SecEnd = getStream().tell();
SectionOffsets[Group] = std::make_pair(SecStart, SecEnd);
}
@@ -1267,25 +1244,25 @@ void ELFObjectWriter::writeObject(MCAsse
align(RelSection->getAlignment());
// Remember the offset into the file for this section.
- uint64_t SecStart = OS.tell();
+ uint64_t SecStart = getStream().tell();
writeRelocations(Asm, *RelSection->getAssociatedSection());
- uint64_t SecEnd = OS.tell();
+ uint64_t SecEnd = getStream().tell();
SectionOffsets[RelSection] = std::make_pair(SecStart, SecEnd);
}
{
- uint64_t SecStart = OS.tell();
+ uint64_t SecStart = getStream().tell();
const MCSectionELF *Sec = createStringTable(Ctx);
- uint64_t SecEnd = OS.tell();
+ uint64_t SecEnd = getStream().tell();
SectionOffsets[Sec] = std::make_pair(SecStart, SecEnd);
}
uint64_t NaturalAlignment = is64Bit() ? 8 : 4;
align(NaturalAlignment);
- const unsigned SectionHeaderOffset = OS.tell();
+ const unsigned SectionHeaderOffset = getStream().tell();
// ... then the section header table ...
writeSectionHeader(Layout, SectionIndexMap, SectionOffsets);
@@ -1301,19 +1278,19 @@ void ELFObjectWriter::writeObject(MCAsse
uint64_t Val = SectionHeaderOffset;
if (sys::IsLittleEndianHost != IsLittleEndian)
sys::swapByteOrder(Val);
- OS.pwrite(reinterpret_cast<char *>(&Val), sizeof(Val),
- offsetof(ELF::Elf64_Ehdr, e_shoff));
+ getStream().pwrite(reinterpret_cast<char *>(&Val), sizeof(Val),
+ offsetof(ELF::Elf64_Ehdr, e_shoff));
NumSectionsOffset = offsetof(ELF::Elf64_Ehdr, e_shnum);
} else {
uint32_t Val = SectionHeaderOffset;
if (sys::IsLittleEndianHost != IsLittleEndian)
sys::swapByteOrder(Val);
- OS.pwrite(reinterpret_cast<char *>(&Val), sizeof(Val),
- offsetof(ELF::Elf32_Ehdr, e_shoff));
+ getStream().pwrite(reinterpret_cast<char *>(&Val), sizeof(Val),
+ offsetof(ELF::Elf32_Ehdr, e_shoff));
NumSectionsOffset = offsetof(ELF::Elf32_Ehdr, e_shnum);
}
- OS.pwrite(reinterpret_cast<char *>(&NumSections), sizeof(NumSections),
- NumSectionsOffset);
+ getStream().pwrite(reinterpret_cast<char *>(&NumSections),
+ sizeof(NumSections), NumSectionsOffset);
}
bool ELFObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
Modified: llvm/trunk/lib/MC/MachObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MachObjectWriter.cpp?rev=246554&r1=246553&r2=246554&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MachObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/MachObjectWriter.cpp Tue Sep 1 11:19:03 2015
@@ -129,7 +129,7 @@ void MachObjectWriter::writeHeader(MachO
// struct mach_header (28 bytes) or
// struct mach_header_64 (32 bytes)
- uint64_t Start = OS.tell();
+ uint64_t Start = getStream().tell();
(void) Start;
write32(is64Bit() ? MachO::MH_MAGIC_64 : MachO::MH_MAGIC);
@@ -144,8 +144,9 @@ void MachObjectWriter::writeHeader(MachO
if (is64Bit())
write32(0); // reserved
- assert(OS.tell() - Start ==
- (is64Bit()?sizeof(MachO::mach_header_64): sizeof(MachO::mach_header)));
+ assert(
+ getStream().tell() - Start ==
+ (is64Bit() ? sizeof(MachO::mach_header_64) : sizeof(MachO::mach_header)));
}
/// writeSegmentLoadCommand - Write a segment load command.
@@ -159,7 +160,7 @@ void MachObjectWriter::writeSegmentLoadC
// struct segment_command (56 bytes) or
// struct segment_command_64 (72 bytes)
- uint64_t Start = OS.tell();
+ uint64_t Start = getStream().tell();
(void) Start;
unsigned SegmentLoadCommandSize =
@@ -190,7 +191,7 @@ void MachObjectWriter::writeSegmentLoadC
write32(NumSections);
write32(0); // flags
- assert(OS.tell() - Start == SegmentLoadCommandSize);
+ assert(getStream().tell() - Start == SegmentLoadCommandSize);
}
void MachObjectWriter::writeSection(const MCAsmLayout &Layout,
@@ -210,7 +211,7 @@ void MachObjectWriter::writeSection(cons
// struct section (68 bytes) or
// struct section_64 (80 bytes)
- uint64_t Start = OS.tell();
+ uint64_t Start = getStream().tell();
(void) Start;
writeBytes(Section.getSectionName(), 16);
@@ -234,8 +235,8 @@ void MachObjectWriter::writeSection(cons
if (is64Bit())
write32(0); // reserved3
- assert(OS.tell() - Start == (is64Bit() ? sizeof(MachO::section_64) :
- sizeof(MachO::section)));
+ assert(getStream().tell() - Start ==
+ (is64Bit() ? sizeof(MachO::section_64) : sizeof(MachO::section)));
}
void MachObjectWriter::writeSymtabLoadCommand(uint32_t SymbolOffset,
@@ -244,7 +245,7 @@ void MachObjectWriter::writeSymtabLoadCo
uint32_t StringTableSize) {
// struct symtab_command (24 bytes)
- uint64_t Start = OS.tell();
+ uint64_t Start = getStream().tell();
(void) Start;
write32(MachO::LC_SYMTAB);
@@ -254,7 +255,7 @@ void MachObjectWriter::writeSymtabLoadCo
write32(StringTableOffset);
write32(StringTableSize);
- assert(OS.tell() - Start == sizeof(MachO::symtab_command));
+ assert(getStream().tell() - Start == sizeof(MachO::symtab_command));
}
void MachObjectWriter::writeDysymtabLoadCommand(uint32_t FirstLocalSymbol,
@@ -267,7 +268,7 @@ void MachObjectWriter::writeDysymtabLoad
uint32_t NumIndirectSymbols) {
// struct dysymtab_command (80 bytes)
- uint64_t Start = OS.tell();
+ uint64_t Start = getStream().tell();
(void) Start;
write32(MachO::LC_DYSYMTAB);
@@ -291,7 +292,7 @@ void MachObjectWriter::writeDysymtabLoad
write32(0); // locreloff
write32(0); // nlocrel
- assert(OS.tell() - Start == sizeof(MachO::dysymtab_command));
+ assert(getStream().tell() - Start == sizeof(MachO::dysymtab_command));
}
MachObjectWriter::MachSymbolData *
@@ -387,7 +388,7 @@ void MachObjectWriter::writeNlist(MachSy
void MachObjectWriter::writeLinkeditLoadCommand(uint32_t Type,
uint32_t DataOffset,
uint32_t DataSize) {
- uint64_t Start = OS.tell();
+ uint64_t Start = getStream().tell();
(void) Start;
write32(Type);
@@ -395,7 +396,7 @@ void MachObjectWriter::writeLinkeditLoad
write32(DataOffset);
write32(DataSize);
- assert(OS.tell() - Start == sizeof(MachO::linkedit_data_command));
+ assert(getStream().tell() - Start == sizeof(MachO::linkedit_data_command));
}
static unsigned ComputeLinkerOptionsLoadCommandSize(
@@ -411,7 +412,7 @@ void MachObjectWriter::writeLinkerOption
const std::vector<std::string> &Options)
{
unsigned Size = ComputeLinkerOptionsLoadCommandSize(Options, is64Bit());
- uint64_t Start = OS.tell();
+ uint64_t Start = getStream().tell();
(void) Start;
write32(MachO::LC_LINKER_OPTION);
@@ -427,7 +428,7 @@ void MachObjectWriter::writeLinkerOption
// Pad to a multiple of the pointer size.
writeBytes("", OffsetToAlignment(BytesWritten, is64Bit() ? 8 : 4));
- assert(OS.tell() - Start == Size);
+ assert(getStream().tell() - Start == Size);
}
void MachObjectWriter::recordRelocation(MCAssembler &Asm,
@@ -906,12 +907,12 @@ void MachObjectWriter::writeObject(MCAss
// Write out the loh commands, if there is one.
if (LOHSize) {
#ifndef NDEBUG
- unsigned Start = OS.tell();
+ unsigned Start = getStream().tell();
#endif
Asm.getLOHContainer().emit(*this, Layout);
// Pad to a multiple of the pointer size.
writeBytes("", OffsetToAlignment(LOHRawSize, is64Bit() ? 8 : 4));
- assert(OS.tell() - Start == LOHSize);
+ assert(getStream().tell() - Start == LOHSize);
}
// Write the symbol table data, if used.
@@ -947,7 +948,7 @@ void MachObjectWriter::writeObject(MCAss
writeNlist(Entry, Layout);
// Write the string table.
- OS << StringTable.data();
+ getStream() << StringTable.data();
}
}
Modified: llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp?rev=246554&r1=246553&r2=246554&view=diff
==============================================================================
--- llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp Tue Sep 1 11:19:03 2015
@@ -1037,10 +1037,11 @@ void WinCOFFObjectWriter::writeObject(MC
continue;
if ((*i)->Header.PointerToRawData != 0) {
- assert(OS.tell() <= (*i)->Header.PointerToRawData &&
+ assert(getStream().tell() <= (*i)->Header.PointerToRawData &&
"Section::PointerToRawData is insane!");
- unsigned SectionDataPadding = (*i)->Header.PointerToRawData - OS.tell();
+ unsigned SectionDataPadding =
+ (*i)->Header.PointerToRawData - getStream().tell();
assert(SectionDataPadding < 4 &&
"Should only need at most three bytes of padding!");
@@ -1050,7 +1051,7 @@ void WinCOFFObjectWriter::writeObject(MC
}
if ((*i)->Relocations.size() > 0) {
- assert(OS.tell() == (*i)->Header.PointerToRelocations &&
+ assert(getStream().tell() == (*i)->Header.PointerToRelocations &&
"Section::PointerToRelocations is insane!");
if ((*i)->Relocations.size() >= 0xffff) {
@@ -1071,14 +1072,14 @@ void WinCOFFObjectWriter::writeObject(MC
}
}
- assert(OS.tell() == Header.PointerToSymbolTable &&
+ assert(getStream().tell() == Header.PointerToSymbolTable &&
"Header::PointerToSymbolTable is insane!");
for (auto &Symbol : Symbols)
if (Symbol->getIndex() != -1)
WriteSymbol(*Symbol);
- OS.write(Strings.data().data(), Strings.data().size());
+ getStream().write(Strings.data().data(), Strings.data().size());
}
MCWinCOFFObjectTargetWriter::MCWinCOFFObjectTargetWriter(unsigned Machine_)
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