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MC: Change MCAssembler::writeSectionData and writeFragmentPadding to take a raw_ostream. NFCI. 

Also clean up a couple of hacks where we were writing the section
contents to another stream by setting the object writer's stream,
writing and setting it back.

Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47038

llvm-svn: 332858
This commit is contained in:
Peter Collingbourne 2018-05-21 18:11:35 +00:00
parent 571a3301ae
commit 147db3e628
8 changed files with 56 additions and 71 deletions
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10
llvm/include/llvm/MC/MCAssembler.h
View File

@ -238,8 +238,8 @@ public:
/// defining a separate atom.
bool isSymbolLinkerVisible(const MCSymbol &SD) const;
/// Emit the section contents using the given object writer.
void writeSectionData(const MCSection *Section,
/// Emit the section contents to \p OS.
void writeSectionData(raw_ostream &OS, const MCSection *Section,
const MCAsmLayout &Layout) const;
/// Check whether a given symbol has been flagged with .thumb_func.
@ -433,10 +433,10 @@ public:
FileNames.push_back(FileName);
}
/// Write the necessary bundle padding to the given object writer.
/// Write the necessary bundle padding to \p OS.
/// Expects a fragment \p F containing instructions and its size \p FSize.
void writeFragmentPadding(const MCFragment &F, uint64_t FSize,
MCObjectWriter *OW) const;
void writeFragmentPadding(raw_ostream &OS, const MCFragment &F,
uint64_t FSize) const;
/// @}

7
llvm/lib/MC/ELFObjectWriter.cpp
View File

@ -996,7 +996,7 @@ void ELFObjectWriter::writeSectionData(const MCAssembler &Asm, MCSection &Sec,
MAI->compressDebugSections() != DebugCompressionType::None;
if (!CompressionEnabled || !SectionName.startswith(".debug_") ||
SectionName == ".debug_frame") {
Asm.writeSectionData(&Section, Layout);
Asm.writeSectionData(getStream(), &Section, Layout);
return;
}
@ -1006,10 +1006,7 @@ void ELFObjectWriter::writeSectionData(const MCAssembler &Asm, MCSection &Sec,
SmallVector<char, 128> UncompressedData;
raw_svector_ostream VecOS(UncompressedData);
raw_pwrite_stream &OldStream = getStream();
setStream(VecOS);
Asm.writeSectionData(&Section, Layout);
setStream(OldStream);
Asm.writeSectionData(VecOS, &Section, Layout);
SmallVector<char, 128> CompressedContents;
if (Error E = zlib::compress(

83
llvm/lib/MC/MCAssembler.cpp
View File

@ -450,8 +450,8 @@ void MCAssembler::registerSymbol(const MCSymbol &Symbol, bool *Created) {
}
}
void MCAssembler::writeFragmentPadding(const MCFragment &F, uint64_t FSize,
MCObjectWriter *OW) const {
void MCAssembler::writeFragmentPadding(raw_ostream &OS, const MCFragment &F,
uint64_t FSize) const {
assert(getBackendPtr() && "Expected assembler backend");
// Should NOP padding be written out before this fragment?
unsigned BundlePadding = F.getBundlePadding();
@ -472,31 +472,30 @@ void MCAssembler::writeFragmentPadding(const MCFragment &F, uint64_t FSize,
// ----------------------------
// ^-------------------^ <- TotalLength
unsigned DistanceToBoundary = TotalLength - getBundleAlignSize();
if (!getBackend().writeNopData(OW->getStream(), DistanceToBoundary))
if (!getBackend().writeNopData(OS, DistanceToBoundary))
report_fatal_error("unable to write NOP sequence of " +
Twine(DistanceToBoundary) + " bytes");
BundlePadding -= DistanceToBoundary;
}
if (!getBackend().writeNopData(OW->getStream(), BundlePadding))
if (!getBackend().writeNopData(OS, BundlePadding))
report_fatal_error("unable to write NOP sequence of " +
Twine(BundlePadding) + " bytes");
}
}
/// Write the fragment \p F to the output file.
static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
const MCFragment &F) {
MCObjectWriter *OW = Asm.getWriterPtr();
assert(OW && "Need ObjectWriter to write fragment");
static void writeFragment(raw_ostream &OS, const MCAssembler &Asm,
const MCAsmLayout &Layout, const MCFragment &F) {
// FIXME: Embed in fragments instead?
uint64_t FragmentSize = Asm.computeFragmentSize(Layout, F);
Asm.writeFragmentPadding(F, FragmentSize, OW);
support::endianness Endian = Asm.getBackend().Endian;
Asm.writeFragmentPadding(OS, F, FragmentSize);
// This variable (and its dummy usage) is to participate in the assert at
// the end of the function.
uint64_t Start = OW->getStream().tell();
uint64_t Start = OS.tell();
(void) Start;
++stats::EmittedFragments;
@ -523,7 +522,7 @@ static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
// bytes left to fill use the Value and ValueSize to fill the rest.
// If we are aligning with nops, ask that target to emit the right data.
if (AF.hasEmitNops()) {
if (!Asm.getBackend().writeNopData(OW->getStream(), Count))
if (!Asm.getBackend().writeNopData(OS, Count))
report_fatal_error("unable to write nop sequence of " +
Twine(Count) + " bytes");
break;
@ -533,10 +532,16 @@ static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
for (uint64_t i = 0; i != Count; ++i) {
switch (AF.getValueSize()) {
default: llvm_unreachable("Invalid size!");
case 1: OW->write8 (uint8_t (AF.getValue())); break;
case 2: OW->write16(uint16_t(AF.getValue())); break;
case 4: OW->write32(uint32_t(AF.getValue())); break;
case 8: OW->write64(uint64_t(AF.getValue())); break;
case 1: OS << char(AF.getValue()); break;
case 2:
support::endian::write<uint16_t>(OS, AF.getValue(), Endian);
break;
case 4:
support::endian::write<uint32_t>(OS, AF.getValue(), Endian);
break;
case 8:
support::endian::write<uint64_t>(OS, AF.getValue(), Endian);
break;
}
}
break;
@ -544,17 +549,17 @@ static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
case MCFragment::FT_Data:
++stats::EmittedDataFragments;
OW->writeBytes(cast<MCDataFragment>(F).getContents());
OS << cast<MCDataFragment>(F).getContents();
break;
case MCFragment::FT_Relaxable:
++stats::EmittedRelaxableFragments;
OW->writeBytes(cast<MCRelaxableFragment>(F).getContents());
OS << cast<MCRelaxableFragment>(F).getContents();
break;
case MCFragment::FT_CompactEncodedInst:
++stats::EmittedCompactEncodedInstFragments;
OW->writeBytes(cast<MCCompactEncodedInstFragment>(F).getContents());
OS << cast<MCCompactEncodedInstFragment>(F).getContents();
break;
case MCFragment::FT_Fill: {
@ -565,10 +570,9 @@ static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
const unsigned MaxChunkSize = 16;
char Data[MaxChunkSize];
// Duplicate V into Data as byte vector to reduce number of
// writes done. As such, do endian conversion here, not in OW.
const bool isLittleEndian = Asm.getContext().getAsmInfo()->isLittleEndian();
// writes done. As such, do endian conversion here.
for (unsigned I = 0; I != VSize; ++I) {
unsigned index = isLittleEndian ? I : (VSize - I - 1);
unsigned index = Endian == support::little ? I : (VSize - I - 1);
Data[I] = uint8_t(V >> (index * 8));
}
for (unsigned I = VSize; I < MaxChunkSize; ++I)
@ -582,25 +586,23 @@ static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
// Do copies by chunk.
StringRef Ref(Data, ChunkSize);
for (uint64_t I = 0, E = FragmentSize / ChunkSize; I != E; ++I)
OW->writeBytes(Ref);
OS << Ref;
// do remainder if needed.
unsigned TrailingCount = FragmentSize % ChunkSize;
if (TrailingCount) {
StringRef RefTail(Data, TrailingCount);
OW->writeBytes(RefTail);
}
if (TrailingCount)
OS.write(Data, TrailingCount);
break;
}
case MCFragment::FT_LEB: {
const MCLEBFragment &LF = cast<MCLEBFragment>(F);
OW->writeBytes(LF.getContents());
OS << LF.getContents();
break;
}
case MCFragment::FT_Padding: {
if (!Asm.getBackend().writeNopData(OW->getStream(), FragmentSize))
if (!Asm.getBackend().writeNopData(OS, FragmentSize))
report_fatal_error("unable to write nop sequence of " +
Twine(FragmentSize) + " bytes");
break;
@ -608,7 +610,7 @@ static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
case MCFragment::FT_SymbolId: {
const MCSymbolIdFragment &SF = cast<MCSymbolIdFragment>(F);
OW->write32(SF.getSymbol()->getIndex());
support::endian::write<uint32_t>(OS, SF.getSymbol()->getIndex(), Endian);
break;
}
@ -617,40 +619,40 @@ static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
const MCOrgFragment &OF = cast<MCOrgFragment>(F);
for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
OW->write8(uint8_t(OF.getValue()));
OS << char(OF.getValue());
break;
}
case MCFragment::FT_Dwarf: {
const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
OW->writeBytes(OF.getContents());
OS << OF.getContents();
break;
}
case MCFragment::FT_DwarfFrame: {
const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
OW->writeBytes(CF.getContents());
OS << CF.getContents();
break;
}
case MCFragment::FT_CVInlineLines: {
const auto &OF = cast<MCCVInlineLineTableFragment>(F);
OW->writeBytes(OF.getContents());
OS << OF.getContents();
break;
}
case MCFragment::FT_CVDefRange: {
const auto &DRF = cast<MCCVDefRangeFragment>(F);
OW->writeBytes(DRF.getContents());
OS << DRF.getContents();
break;
}
case MCFragment::FT_Dummy:
llvm_unreachable("Should not have been added");
}
assert(OW->getStream().tell() - Start == FragmentSize &&
assert(OS.tell() - Start == FragmentSize &&
"The stream should advance by fragment size");
}
void MCAssembler::writeSectionData(const MCSection *Sec,
void MCAssembler::writeSectionData(raw_ostream &OS, const MCSection *Sec,
const MCAsmLayout &Layout) const {
assert(getBackendPtr() && "Expected assembler backend");
@ -696,14 +698,13 @@ void MCAssembler::writeSectionData(const MCSection *Sec,
return;
}
uint64_t Start = getWriter().getStream().tell();
uint64_t Start = OS.tell();
(void)Start;
for (const MCFragment &F : *Sec)
writeFragment(*this, Layout, F);
writeFragment(OS, *this, Layout, F);
assert(getWriter().getStream().tell() - Start ==
Layout.getSectionAddressSize(Sec));
assert(OS.tell() - Start == Layout.getSectionAddressSize(Sec));
}
std::tuple<MCValue, uint64_t, bool>

9
llvm/lib/MC/MCELFStreamer.cpp
View File

@ -69,13 +69,8 @@ void MCELFStreamer::mergeFragment(MCDataFragment *DF,
if (RequiredBundlePadding > 0) {
SmallString<256> Code;
raw_svector_ostream VecOS(Code);
{
auto OW = Assembler.getBackend().createObjectWriter(VecOS);
EF->setBundlePadding(static_cast<uint8_t>(RequiredBundlePadding));
Assembler.writeFragmentPadding(*EF, FSize, OW.get());
}
EF->setBundlePadding(static_cast<uint8_t>(RequiredBundlePadding));
Assembler.writeFragmentPadding(VecOS, *EF, FSize);
DF->getContents().append(Code.begin(), Code.end());
}

2
llvm/lib/MC/MachObjectWriter.cpp
View File

@ -919,7 +919,7 @@ void MachObjectWriter::writeObject(MCAssembler &Asm,
// Write the actual section data.
for (const MCSection &Sec : Asm) {
Asm.writeSectionData(&Sec, Layout);
Asm.writeSectionData(getStream(), &Sec, Layout);
uint64_t Pad = getPaddingSize(&Sec, Layout);
WriteZeros(Pad);

4
llvm/lib/MC/WasmObjectWriter.cpp
View File

@ -853,7 +853,7 @@ void WasmObjectWriter::writeCodeSection(const MCAssembler &Asm,
encodeULEB128(Size, getStream());
FuncSection.setSectionOffset(getStream().tell() - Section.ContentsOffset);
Asm.writeSectionData(&FuncSection, Layout);
Asm.writeSectionData(getStream(), &FuncSection, Layout);
}
// Apply fixups.
@ -1016,7 +1016,7 @@ void WasmObjectWriter::writeCustomSections(const MCAssembler &Asm,
startCustomSection(Section, CustomSection.Name);
Sec->setSectionOffset(getStream().tell() - Section.ContentsOffset);
Asm.writeSectionData(Sec, Layout);
Asm.writeSectionData(getStream(), Sec, Layout);
CustomSection.OutputContentsOffset = Section.ContentsOffset;
CustomSection.OutputIndex = Section.Index;

10
llvm/lib/MC/WinCOFFObjectWriter.cpp
View File

@ -608,15 +608,7 @@ uint32_t WinCOFFObjectWriter::writeSectionContents(MCAssembler &Asm,
// to CRC the data before we dump it into the object file.
SmallVector<char, 128> Buf;
raw_svector_ostream VecOS(Buf);
raw_pwrite_stream &OldStream = getStream();
// Redirect the output stream to our buffer and fill our buffer with
// the section data.
setStream(VecOS);
Asm.writeSectionData(&MCSec, Layout);
// Reset the stream back to what it was before.
setStream(OldStream);
Asm.writeSectionData(VecOS, &MCSec, Layout);
// Write the section contents to the object file.
getStream() << Buf;

2
llvm/tools/dsymutil/MachOUtils.cpp
View File

@ -516,7 +516,7 @@ bool generateDsymCompanion(const DebugMap &DM, MCStreamer &MS,
uint64_t Pos = OutFile.tell();
Writer.WriteZeros(alignTo(Pos, Sec.getAlignment()) - Pos);
MCAsm.writeSectionData(&Sec, Layout);
MCAsm.writeSectionData(OutFile, &Sec, Layout);
}
return true;