Commit d83a2faa authored by jasonliu's avatar jasonliu
Browse files

[NFCI][XCOFF][AIX] Skip empty Section during object file generation 

This is a fix to D69112 where we common up the logic of writing CsectGroup.
However, we forget to skip the Sections that are empty in that patch.

Reviewed by: daltenty, xingxue

Differential Revision: https://reviews.llvm.org/D69447
parent 5ae881f9

llvm/lib/MC/XCOFFObjectWriter.cpp

+18 −6
Original line number Diff line number Diff line
@@ -148,6 +148,7 @@ class XCOFFObjectWriter : public MCObjectWriter { 


  uint32_t SymbolTableEntryCount = 0;

  uint32_t SymbolTableOffset = 0;

  uint16_t SectionCount = 0;



  support::endian::Writer W;

  std::unique_ptr<MCXCOFFObjectTargetWriter> TargetObjectWriter;
@@ -234,6 +235,7 @@ void XCOFFObjectWriter::reset() { 
  // Reset the symbol table and string table.

  SymbolTableEntryCount = 0;

  SymbolTableOffset = 0;

  SectionCount = 0;

  Strings.clear();



  MCObjectWriter::reset();
@@ -467,7 +469,7 @@ void XCOFFObjectWriter::writeFileHeader() { 
  // Magic.

  W.write<uint16_t>(0x01df);

  // Number of sections.

  W.write<uint16_t>(Sections.size());

  W.write<uint16_t>(SectionCount);

  // Timestamp field. For reproducible output we write a 0, which represents no

  // timestamp.

  W.write<int32_t>(0);
@@ -483,6 +485,10 @@ void XCOFFObjectWriter::writeFileHeader() { 


void XCOFFObjectWriter::writeSectionHeaderTable() {

  for (const auto *Sec : Sections) {

    // Nothing to write for this Section.

    if (Sec->Index == Section::UninitializedIndex)

      continue;



    // Write Name.

    ArrayRef<char> NameRef(Sec->Name, XCOFF::NameSize);

    W.write(NameRef);
@@ -509,6 +515,10 @@ void XCOFFObjectWriter::writeSectionHeaderTable() { 


void XCOFFObjectWriter::writeSymbolTable(const MCAsmLayout &Layout) {

  for (const auto *Section : Sections) {

    // Nothing to write for this Section.

    if (Section->Index == Section::UninitializedIndex)

      continue;



    for (const auto *Group : Section->Groups) {

      if (Group->Csects.empty())

        continue;
@@ -555,6 +565,7 @@ void XCOFFObjectWriter::assignAddressesAndIndices(const MCAsmLayout &Layout) { 
    if (SectionIndex > MaxSectionIndex)

      report_fatal_error("Section index overflow!");

    Section->Index = SectionIndex++;

    SectionCount++;



    bool SectionAddressSet = false;

    for (auto *Group : Section->Groups) {
@@ -598,13 +609,14 @@ void XCOFFObjectWriter::assignAddressesAndIndices(const MCAsmLayout &Layout) { 


  // Calculate the RawPointer value for each section.

  uint64_t RawPointer = sizeof(XCOFF::FileHeader32) + auxiliaryHeaderSize() +

                        Sections.size() * sizeof(XCOFF::SectionHeader32);

                        SectionCount * sizeof(XCOFF::SectionHeader32);

  for (auto *Sec : Sections) {

    if (!Sec->IsVirtual) {

    if (Sec->Index == Section::UninitializedIndex || Sec->IsVirtual)

      continue;



    Sec->FileOffsetToData = RawPointer;

    RawPointer += Sec->Size;

  }

  }



  // TODO Add in Relocation storage to the RawPointer Calculation.

  // TODO What to align the SymbolTable to?