Centralize the information about which object format we are using.
[oota-llvm.git] / lib / MC / ELFObjectWriter.cpp
index f8cf7d2ea5d3ce2b4c4dcda06231454ad2cb0ccc..e925bc272dc8a3ae1783c38f90cd9e69a72c74e5 100644 (file)
@@ -116,8 +116,6 @@ class ELFObjectWriter : public MCObjectWriter {
     unsigned StringTableIndex;
     // This holds the .symtab section index.
     unsigned SymbolTableIndex;
-    // This holds the .symtab_shndx section index.
-    unsigned SymtabShndxSectionIndex = 0;
 
     // Sections in the order they are to be output in the section table.
     std::vector<const MCSectionELF *> SectionTable;
@@ -133,6 +131,8 @@ class ELFObjectWriter : public MCObjectWriter {
       return TargetObjectWriter->GetRelocType(Target, Fixup, IsPCRel);
     }
 
+    void align(unsigned Alignment);
+
   public:
     ELFObjectWriter(MCELFObjectTargetWriter *MOTW, raw_pwrite_stream &OS,
                     bool IsLittleEndian)
@@ -150,9 +150,9 @@ class ELFObjectWriter : public MCObjectWriter {
 
     void WriteWord(uint64_t W) {
       if (is64Bit())
-        Write64(W);
+        write64(W);
       else
-        Write32(W);
+        write32(W);
     }
 
     template <typename T> void write(T Val) {
@@ -176,7 +176,7 @@ class ELFObjectWriter : public MCObjectWriter {
                                   const MCSymbol *Sym, uint64_t C,
                                   unsigned Type) const;
 
-    void RecordRelocation(MCAssembler &Asm, const MCAsmLayout &Layout,
+    void recordRelocation(MCAssembler &Asm, const MCAsmLayout &Layout,
                           const MCFragment *Fragment, const MCFixup &Fixup,
                           MCValue Target, bool &IsPCRel,
                           uint64_t &FixedValue) override;
@@ -199,10 +199,10 @@ class ELFObjectWriter : public MCObjectWriter {
 
     const MCSectionELF *createStringTable(MCContext &Ctx);
 
-    void ExecutePostLayoutBinding(MCAssembler &Asm,
+    void executePostLayoutBinding(MCAssembler &Asm,
                                   const MCAsmLayout &Layout) override;
 
-    void writeSectionHeader(const MCAssembler &Asm, const MCAsmLayout &Layout,
+    void writeSectionHeader(const MCAsmLayout &Layout,
                             const SectionIndexMapTy &SectionIndexMap,
                             const SectionOffsetsTy &SectionOffsets);
 
@@ -216,7 +216,7 @@ class ELFObjectWriter : public MCObjectWriter {
 
     void writeRelocations(const MCAssembler &Asm, const MCSectionELF &Sec);
 
-    bool IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
+    bool isSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
                                                 const MCSymbol &SymA,
                                                 const MCFragment &FB,
                                                 bool InSet,
@@ -224,13 +224,18 @@ class ELFObjectWriter : public MCObjectWriter {
 
     bool isWeak(const MCSymbol &Sym) const override;
 
-    void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout) override;
+    void writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) override;
     void writeSection(const SectionIndexMapTy &SectionIndexMap,
                       uint32_t GroupSymbolIndex, uint64_t Offset, uint64_t Size,
                       const MCSectionELF &Section);
   };
 }
 
+void ELFObjectWriter::align(unsigned Alignment) {
+  uint64_t Padding = OffsetToAlignment(OS.tell(), Alignment);
+  WriteZeros(Padding);
+}
+
 unsigned ELFObjectWriter::addToSectionTable(const MCSectionELF *Sec) {
   SectionTable.push_back(Sec);
   StrTabBuilder.add(Sec->getSectionName());
@@ -307,47 +312,47 @@ void ELFObjectWriter::writeHeader(const MCAssembler &Asm) {
   // emitWord method behaves differently for ELF32 and ELF64, writing
   // 4 bytes in the former and 8 in the latter.
 
-  WriteBytes(ELF::ElfMagic); // e_ident[EI_MAG0] to e_ident[EI_MAG3]
+  writeBytes(ELF::ElfMagic); // e_ident[EI_MAG0] to e_ident[EI_MAG3]
 
-  Write8(is64Bit() ? ELF::ELFCLASS64 : ELF::ELFCLASS32); // e_ident[EI_CLASS]
+  write8(is64Bit() ? ELF::ELFCLASS64 : ELF::ELFCLASS32); // e_ident[EI_CLASS]
 
   // e_ident[EI_DATA]
-  Write8(isLittleEndian() ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
+  write8(isLittleEndian() ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
 
-  Write8(ELF::EV_CURRENT);        // e_ident[EI_VERSION]
+  write8(ELF::EV_CURRENT);        // e_ident[EI_VERSION]
   // e_ident[EI_OSABI]
-  Write8(TargetObjectWriter->getOSABI());
-  Write8(0);                  // e_ident[EI_ABIVERSION]
+  write8(TargetObjectWriter->getOSABI());
+  write8(0);                  // e_ident[EI_ABIVERSION]
 
   WriteZeros(ELF::EI_NIDENT - ELF::EI_PAD);
 
-  Write16(ELF::ET_REL);             // e_type
+  write16(ELF::ET_REL);             // e_type
 
-  Write16(TargetObjectWriter->getEMachine()); // e_machine = target
+  write16(TargetObjectWriter->getEMachine()); // e_machine = target
 
-  Write32(ELF::EV_CURRENT);         // e_version
+  write32(ELF::EV_CURRENT);         // e_version
   WriteWord(0);                    // e_entry, no entry point in .o file
   WriteWord(0);                    // e_phoff, no program header for .o
   WriteWord(0);                     // e_shoff = sec hdr table off in bytes
 
   // e_flags = whatever the target wants
-  Write32(Asm.getELFHeaderEFlags());
+  write32(Asm.getELFHeaderEFlags());
 
   // e_ehsize = ELF header size
-  Write16(is64Bit() ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr));
+  write16(is64Bit() ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr));
 
-  Write16(0);                  // e_phentsize = prog header entry size
-  Write16(0);                  // e_phnum = # prog header entries = 0
+  write16(0);                  // e_phentsize = prog header entry size
+  write16(0);                  // e_phnum = # prog header entries = 0
 
   // e_shentsize = Section header entry size
-  Write16(is64Bit() ? sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr));
+  write16(is64Bit() ? sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr));
 
   // e_shnum     = # of section header ents
-  Write16(0);
+  write16(0);
 
   // e_shstrndx  = Section # of '.shstrtab'
   assert(StringTableIndex < ELF::SHN_LORESERVE);
-  Write16(StringTableIndex);
+  write16(StringTableIndex);
 }
 
 uint64_t ELFObjectWriter::SymbolValue(const MCSymbol &Sym,
@@ -365,7 +370,7 @@ uint64_t ELFObjectWriter::SymbolValue(const MCSymbol &Sym,
   return Res;
 }
 
-void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
+void ELFObjectWriter::executePostLayoutBinding(MCAssembler &Asm,
                                                const MCAsmLayout &Layout) {
   // The presence of symbol versions causes undefined symbols and
   // versions declared with @@@ to be renamed.
@@ -605,7 +610,7 @@ static bool isWeak(const MCSymbolELF &Sym) {
   }
 }
 
-void ELFObjectWriter::RecordRelocation(MCAssembler &Asm,
+void ELFObjectWriter::recordRelocation(MCAssembler &Asm,
                                        const MCAsmLayout &Layout,
                                        const MCFragment *Fragment,
                                        const MCFixup &Fixup, MCValue Target,
@@ -688,6 +693,8 @@ void ELFObjectWriter::RecordRelocation(MCAssembler &Asm,
     auto *ELFSec = cast_or_null<MCSectionELF>(SecA);
     const auto *SectionSymbol =
         ELFSec ? cast<MCSymbolELF>(ELFSec->getBeginSymbol()) : nullptr;
+    if (SectionSymbol)
+      SectionSymbol->setUsedInReloc();
     ELFRelocationEntry Rec(FixupOffset, SectionSymbol, Type, Addend);
     Relocations[&FixupSection].push_back(Rec);
     return;
@@ -733,12 +740,12 @@ bool ELFObjectWriter::isInSymtab(const MCAsmLayout &Layout,
   if (Symbol.isUndefined() && !Symbol.isBindingSet())
     return false;
 
-  if (Symbol.getType() == ELF::STT_SECTION)
-    return true;
-
   if (Symbol.isTemporary())
     return false;
 
+  if (Symbol.getType() == ELF::STT_SECTION)
+    return false;
+
   return true;
 }
 
@@ -756,10 +763,7 @@ void ELFObjectWriter::computeSymbolTable(
   SymtabSection->setAlignment(is64Bit() ? 8 : 4);
   SymbolTableIndex = addToSectionTable(SymtabSection);
 
-  uint64_t Padding =
-      OffsetToAlignment(OS.tell(), SymtabSection->getAlignment());
-  WriteZeros(Padding);
-
+  align(SymtabSection->getAlignment());
   uint64_t SecStart = OS.tell();
 
   // The first entry is the undefined symbol entry.
@@ -780,10 +784,15 @@ void ELFObjectWriter::computeSymbolTable(
                     Renames.count(&Symbol)))
       continue;
 
+    if (Symbol.isTemporary() && Symbol.isUndefined())
+      Ctx.reportFatalError(SMLoc(), "Undefined temporary");
+
     ELFSymbolData MSD;
     MSD.Symbol = cast<MCSymbolELF>(&Symbol);
 
     bool Local = Symbol.getBinding() == ELF::STB_LOCAL;
+    assert(Local || !Symbol.isTemporary());
+
     if (Symbol.isAbsolute()) {
       MSD.SectionIndex = ELF::SHN_ABS;
     } else if (Symbol.isCommon()) {
@@ -830,12 +839,12 @@ void ELFObjectWriter::computeSymbolTable(
     // seems that this information is not easily accessible from the
     // ELFObjectWriter.
     StringRef Name = Symbol.getName();
+    SmallString<32> Buf;
     if (!Name.startswith("?") && !Name.startswith("@?") &&
         !Name.startswith("__imp_?") && !Name.startswith("__imp_@?")) {
       // This symbol isn't following the MSVC C++ name mangling convention. We
       // can thus safely interpret the @@@ in symbol names as specifying symbol
       // versioning.
-      SmallString<32> Buf;
       size_t Pos = Name.find("@@@");
       if (Pos != StringRef::npos) {
         Buf += Name.substr(0, Pos);
@@ -855,6 +864,9 @@ void ELFObjectWriter::computeSymbolTable(
       ExternalSymbolData.push_back(MSD);
   }
 
+  // This holds the .symtab_shndx section index.
+  unsigned SymtabShndxSectionIndex = 0;
+
   if (HasLargeSectionIndex) {
     MCSectionELF *SymtabShndxSection =
         Ctx.getELFSection(".symtab_shndxr", ELF::SHT_SYMTAB_SHNDX, 0, 4, "");
@@ -1033,14 +1045,14 @@ void ELFObjectWriter::WriteSecHdrEntry(uint32_t Name, uint32_t Type,
                                        uint32_t Link, uint32_t Info,
                                        uint64_t Alignment,
                                        uint64_t EntrySize) {
-  Write32(Name);        // sh_name: index into string table
-  Write32(Type);        // sh_type
+  write32(Name);        // sh_name: index into string table
+  write32(Type);        // sh_type
   WriteWord(Flags);     // sh_flags
   WriteWord(Address);   // sh_addr
   WriteWord(Offset);    // sh_offset
   WriteWord(Size);      // sh_size
-  Write32(Link);        // sh_link
-  Write32(Info);        // sh_info
+  write32(Link);        // sh_link
+  write32(Info);        // sh_info
   WriteWord(Alignment); // sh_addralign
   WriteWord(EntrySize); // sh_entsize
 }
@@ -1142,8 +1154,7 @@ void ELFObjectWriter::writeSection(const SectionIndexMapTy &SectionIndexMap,
 }
 
 void ELFObjectWriter::writeSectionHeader(
-    const MCAssembler &Asm, const MCAsmLayout &Layout,
-    const SectionIndexMapTy &SectionIndexMap,
+    const MCAsmLayout &Layout, const SectionIndexMapTy &SectionIndexMap,
     const SectionOffsetsTy &SectionOffsets) {
   const unsigned NumSections = SectionTable.size();
 
@@ -1173,7 +1184,7 @@ void ELFObjectWriter::writeSectionHeader(
   }
 }
 
-void ELFObjectWriter::WriteObject(MCAssembler &Asm,
+void ELFObjectWriter::writeObject(MCAssembler &Asm,
                                   const MCAsmLayout &Layout) {
   MCContext &Ctx = Asm.getContext();
   MCSectionELF *StrtabSection =
@@ -1195,8 +1206,7 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
   for (MCSection &Sec : Asm) {
     MCSectionELF &Section = static_cast<MCSectionELF &>(Sec);
 
-    uint64_t Padding = OffsetToAlignment(OS.tell(), Section.getAlignment());
-    WriteZeros(Padding);
+    align(Section.getAlignment());
 
     // Remember the offset into the file for this section.
     uint64_t SecStart = OS.tell();
@@ -1218,9 +1228,11 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
         Group->setAlignment(4);
         Groups.push_back(Group);
       }
-      GroupMembers[SignatureSymbol].push_back(&Section);
+      std::vector<const MCSectionELF *> &Members =
+          GroupMembers[SignatureSymbol];
+      Members.push_back(&Section);
       if (RelSection)
-        GroupMembers[SignatureSymbol].push_back(RelSection);
+        Members.push_back(RelSection);
     }
 
     SectionIndexMap[&Section] = addToSectionTable(&Section);
@@ -1231,8 +1243,7 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
   }
 
   for (MCSectionELF *Group : Groups) {
-    uint64_t Padding = OffsetToAlignment(OS.tell(), Group->getAlignment());
-    WriteZeros(Padding);
+    align(Group->getAlignment());
 
     // Remember the offset into the file for this section.
     uint64_t SecStart = OS.tell();
@@ -1253,8 +1264,7 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
   computeSymbolTable(Asm, Layout, SectionIndexMap, RevGroupMap, SectionOffsets);
 
   for (MCSectionELF *RelSection : Relocations) {
-    uint64_t Padding = OffsetToAlignment(OS.tell(), RelSection->getAlignment());
-    WriteZeros(Padding);
+    align(RelSection->getAlignment());
 
     // Remember the offset into the file for this section.
     uint64_t SecStart = OS.tell();
@@ -1273,13 +1283,12 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
   }
 
   uint64_t NaturalAlignment = is64Bit() ? 8 : 4;
-  uint64_t Padding = OffsetToAlignment(OS.tell(), NaturalAlignment);
-  WriteZeros(Padding);
+  align(NaturalAlignment);
 
   const unsigned SectionHeaderOffset = OS.tell();
 
   // ... then the section header table ...
-  writeSectionHeader(Asm, Layout, SectionIndexMap, SectionOffsets);
+  writeSectionHeader(Layout, SectionIndexMap, SectionOffsets);
 
   uint16_t NumSections = (SectionTable.size() + 1 >= ELF::SHN_LORESERVE)
                              ? (uint16_t)ELF::SHN_UNDEF
@@ -1307,7 +1316,7 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
             NumSectionsOffset);
 }
 
-bool ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
+bool ELFObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
     const MCAssembler &Asm, const MCSymbol &SA, const MCFragment &FB,
     bool InSet, bool IsPCRel) const {
   const auto &SymA = cast<MCSymbolELF>(SA);
@@ -1316,7 +1325,7 @@ bool ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
     if (::isWeak(SymA))
       return false;
   }
-  return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(Asm, SymA, FB,
+  return MCObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(Asm, SymA, FB,
                                                                 InSet, IsPCRel);
 }