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Diffstat (limited to 'llvm/lib/MC/ELFObjectWriter.cpp')
-rw-r--r--llvm/lib/MC/ELFObjectWriter.cpp103
1 files changed, 71 insertions, 32 deletions
diff --git a/llvm/lib/MC/ELFObjectWriter.cpp b/llvm/lib/MC/ELFObjectWriter.cpp
index f6360c4e2f21..07ed3409707b 100644
--- a/llvm/lib/MC/ELFObjectWriter.cpp
+++ b/llvm/lib/MC/ELFObjectWriter.cpp
@@ -142,11 +142,11 @@ struct ELFWriter {
bool is64Bit() const;
bool usesRela(const MCSectionELF &Sec) const;
- uint64_t align(unsigned Alignment);
+ uint64_t align(Align Alignment);
bool maybeWriteCompression(uint32_t ChType, uint64_t Size,
SmallVectorImpl<uint8_t> &CompressedContents,
- unsigned Alignment);
+ Align Alignment);
public:
ELFWriter(ELFObjectWriter &OWriter, raw_pwrite_stream &OS,
@@ -192,6 +192,8 @@ public:
MCSectionELF *createRelocationSection(MCContext &Ctx,
const MCSectionELF &Sec);
+ void createMemtagRelocs(MCAssembler &Asm);
+
void writeSectionHeader(const MCAsmLayout &Layout,
const SectionIndexMapTy &SectionIndexMap,
const SectionOffsetsTy &SectionOffsets);
@@ -201,7 +203,7 @@ public:
void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
uint64_t Address, uint64_t Offset, uint64_t Size,
- uint32_t Link, uint32_t Info, uint64_t Alignment,
+ uint32_t Link, uint32_t Info, MaybeAlign Alignment,
uint64_t EntrySize);
void writeRelocations(const MCAssembler &Asm, const MCSectionELF &Sec);
@@ -317,8 +319,9 @@ public:
} // end anonymous namespace
-uint64_t ELFWriter::align(unsigned Alignment) {
- uint64_t Offset = W.OS.tell(), NewOffset = alignTo(Offset, Alignment);
+uint64_t ELFWriter::align(Align Alignment) {
+ uint64_t Offset = W.OS.tell();
+ uint64_t NewOffset = alignTo(Offset, Alignment);
W.OS.write_zeros(NewOffset - Offset);
return NewOffset;
}
@@ -451,7 +454,7 @@ void ELFWriter::writeHeader(const MCAssembler &Asm) {
uint64_t ELFWriter::SymbolValue(const MCSymbol &Sym,
const MCAsmLayout &Layout) {
if (Sym.isCommon())
- return Sym.getCommonAlignment();
+ return Sym.getCommonAlignment()->value();
uint64_t Res;
if (!Layout.getSymbolOffset(Sym, Res))
@@ -608,6 +611,23 @@ bool ELFWriter::isInSymtab(const MCAsmLayout &Layout, const MCSymbolELF &Symbol,
return true;
}
+void ELFWriter::createMemtagRelocs(MCAssembler &Asm) {
+ MCSectionELF *MemtagRelocs = nullptr;
+ for (const MCSymbol &Sym : Asm.symbols()) {
+ const auto &SymE = cast<MCSymbolELF>(Sym);
+ if (!SymE.isMemtag())
+ continue;
+ if (MemtagRelocs == nullptr) {
+ MemtagRelocs = OWriter.TargetObjectWriter->getMemtagRelocsSection(Asm.getContext());
+ if (MemtagRelocs == nullptr)
+ report_fatal_error("Tagged globals are not available on this architecture.");
+ Asm.registerSection(*MemtagRelocs);
+ }
+ ELFRelocationEntry Rec(0, &SymE, ELF::R_AARCH64_NONE, 0, nullptr, 0);
+ OWriter.Relocations[MemtagRelocs].push_back(Rec);
+ }
+}
+
void ELFWriter::computeSymbolTable(
MCAssembler &Asm, const MCAsmLayout &Layout,
const SectionIndexMapTy &SectionIndexMap, const RevGroupMapTy &RevGroupMap,
@@ -622,7 +642,7 @@ void ELFWriter::computeSymbolTable(
SymtabSection->setAlignment(is64Bit() ? Align(8) : Align(4));
SymbolTableIndex = addToSectionTable(SymtabSection);
- uint64_t SecStart = align(SymtabSection->getAlignment());
+ uint64_t SecStart = align(SymtabSection->getAlign());
// The first entry is the undefined symbol entry.
Writer.writeSymbol(0, 0, 0, 0, 0, 0, false);
@@ -786,7 +806,8 @@ void ELFWriter::computeSymbolTable(
void ELFWriter::writeAddrsigSection() {
for (const MCSymbol *Sym : OWriter.AddrsigSyms)
- encodeULEB128(Sym->getIndex(), W.OS);
+ if (Sym->getIndex() != 0)
+ encodeULEB128(Sym->getIndex(), W.OS);
}
MCSectionELF *ELFWriter::createRelocationSection(MCContext &Ctx,
@@ -819,7 +840,7 @@ MCSectionELF *ELFWriter::createRelocationSection(MCContext &Ctx,
// Include the debug info compression header.
bool ELFWriter::maybeWriteCompression(
uint32_t ChType, uint64_t Size,
- SmallVectorImpl<uint8_t> &CompressedContents, unsigned Alignment) {
+ SmallVectorImpl<uint8_t> &CompressedContents, Align Alignment) {
uint64_t HdrSize =
is64Bit() ? sizeof(ELF::Elf32_Chdr) : sizeof(ELF::Elf64_Chdr);
if (Size <= HdrSize + CompressedContents.size())
@@ -830,12 +851,12 @@ bool ELFWriter::maybeWriteCompression(
write(static_cast<ELF::Elf64_Word>(ChType));
write(static_cast<ELF::Elf64_Word>(0)); // ch_reserved field.
write(static_cast<ELF::Elf64_Xword>(Size));
- write(static_cast<ELF::Elf64_Xword>(Alignment));
+ write(static_cast<ELF::Elf64_Xword>(Alignment.value()));
} else {
// Write Elf32_Chdr header otherwise.
write(static_cast<ELF::Elf32_Word>(ChType));
write(static_cast<ELF::Elf32_Word>(Size));
- write(static_cast<ELF::Elf32_Word>(Alignment));
+ write(static_cast<ELF::Elf32_Word>(Alignment.value()));
}
return true;
}
@@ -848,29 +869,36 @@ void ELFWriter::writeSectionData(const MCAssembler &Asm, MCSection &Sec,
auto &MC = Asm.getContext();
const auto &MAI = MC.getAsmInfo();
- bool CompressionEnabled =
- MAI->compressDebugSections() != DebugCompressionType::None;
- if (!CompressionEnabled || !SectionName.startswith(".debug_")) {
+ const DebugCompressionType CompressionType = MAI->compressDebugSections();
+ if (CompressionType == DebugCompressionType::None ||
+ !SectionName.startswith(".debug_")) {
Asm.writeSectionData(W.OS, &Section, Layout);
return;
}
- assert(MAI->compressDebugSections() == DebugCompressionType::Z &&
- "expected zlib style compression");
-
SmallVector<char, 128> UncompressedData;
raw_svector_ostream VecOS(UncompressedData);
Asm.writeSectionData(VecOS, &Section, Layout);
+ ArrayRef<uint8_t> Uncompressed =
+ ArrayRef(reinterpret_cast<uint8_t *>(UncompressedData.data()),
+ UncompressedData.size());
SmallVector<uint8_t, 128> Compressed;
- const uint32_t ChType = ELF::ELFCOMPRESS_ZLIB;
- compression::zlib::compress(
- makeArrayRef(reinterpret_cast<uint8_t *>(UncompressedData.data()),
- UncompressedData.size()),
- Compressed);
-
+ uint32_t ChType;
+ switch (CompressionType) {
+ case DebugCompressionType::None:
+ llvm_unreachable("has been handled");
+ case DebugCompressionType::Zlib:
+ ChType = ELF::ELFCOMPRESS_ZLIB;
+ break;
+ case DebugCompressionType::Zstd:
+ ChType = ELF::ELFCOMPRESS_ZSTD;
+ break;
+ }
+ compression::compress(compression::Params(CompressionType), Uncompressed,
+ Compressed);
if (!maybeWriteCompression(ChType, UncompressedData.size(), Compressed,
- Sec.getAlignment())) {
+ Sec.getAlign())) {
W.OS << UncompressedData;
return;
}
@@ -885,7 +913,7 @@ void ELFWriter::writeSectionData(const MCAssembler &Asm, MCSection &Sec,
void ELFWriter::WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
uint64_t Address, uint64_t Offset,
uint64_t Size, uint32_t Link, uint32_t Info,
- uint64_t Alignment, uint64_t EntrySize) {
+ MaybeAlign Alignment, uint64_t EntrySize) {
W.write<uint32_t>(Name); // sh_name: index into string table
W.write<uint32_t>(Type); // sh_type
WriteWord(Flags); // sh_flags
@@ -894,7 +922,7 @@ void ELFWriter::WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
WriteWord(Size); // sh_size
W.write<uint32_t>(Link); // sh_link
W.write<uint32_t>(Info); // sh_info
- WriteWord(Alignment); // sh_addralign
+ WriteWord(Alignment ? Alignment->value() : 0); // sh_addralign
WriteWord(EntrySize); // sh_entsize
}
@@ -1016,7 +1044,7 @@ void ELFWriter::writeSection(const SectionIndexMapTy &SectionIndexMap,
WriteSecHdrEntry(StrTabBuilder.getOffset(Section.getName()),
Section.getType(), Section.getFlags(), 0, Offset, Size,
- sh_link, sh_info, Section.getAlignment(),
+ sh_link, sh_info, Section.getAlign(),
Section.getEntrySize());
}
@@ -1028,7 +1056,7 @@ void ELFWriter::writeSectionHeader(
// Null section first.
uint64_t FirstSectionSize =
(NumSections + 1) >= ELF::SHN_LORESERVE ? NumSections + 1 : 0;
- WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, 0, 0, 0, 0);
+ WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, 0, 0, std::nullopt, 0);
for (const MCSectionELF *Section : SectionTable) {
uint32_t GroupSymbolIndex;
@@ -1059,6 +1087,8 @@ uint64_t ELFWriter::writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) {
Ctx.getELFSection(".strtab", ELF::SHT_STRTAB, 0);
StringTableIndex = addToSectionTable(StrtabSection);
+ createMemtagRelocs(Asm);
+
RevGroupMapTy RevGroupMap;
SectionIndexMapTy SectionIndexMap;
@@ -1079,7 +1109,7 @@ uint64_t ELFWriter::writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) {
continue;
// Remember the offset into the file for this section.
- const uint64_t SecStart = align(Section.getAlignment());
+ const uint64_t SecStart = align(Section.getAlign());
const MCSymbolELF *SignatureSymbol = Section.getGroup();
writeSectionData(Asm, Section, Layout);
@@ -1116,7 +1146,7 @@ uint64_t ELFWriter::writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) {
for (MCSectionELF *Group : Groups) {
// Remember the offset into the file for this section.
- const uint64_t SecStart = align(Group->getAlignment());
+ const uint64_t SecStart = align(Group->getAlign());
const MCSymbol *SignatureSymbol = Group->getGroup();
assert(SignatureSymbol);
@@ -1148,7 +1178,7 @@ uint64_t ELFWriter::writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) {
for (MCSectionELF *RelSection : Relocations) {
// Remember the offset into the file for this section.
- const uint64_t SecStart = align(RelSection->getAlignment());
+ const uint64_t SecStart = align(RelSection->getAlign());
writeRelocations(Asm,
cast<MCSectionELF>(*RelSection->getLinkedToSection()));
@@ -1171,7 +1201,7 @@ uint64_t ELFWriter::writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) {
SectionOffsets[StrtabSection] = std::make_pair(SecStart, W.OS.tell());
}
- const uint64_t SectionHeaderOffset = align(is64Bit() ? 8 : 4);
+ const uint64_t SectionHeaderOffset = align(is64Bit() ? Align(8) : Align(4));
// ... then the section header table ...
writeSectionHeader(Layout, SectionIndexMap, SectionOffsets);
@@ -1308,6 +1338,15 @@ bool ELFObjectWriter::shouldRelocateWithSymbol(const MCAssembler &Asm,
if (Sym->isUndefined())
return true;
+ // For memory-tagged symbols, ensure that the relocation uses the symbol. For
+ // tagged symbols, we emit an empty relocation (R_AARCH64_NONE) in a special
+ // section (SHT_AARCH64_MEMTAG_GLOBALS_STATIC) to indicate to the linker that
+ // this global needs to be tagged. In addition, the linker needs to know
+ // whether to emit a special addend when relocating `end` symbols, and this
+ // can only be determined by the attributes of the symbol itself.
+ if (Sym->isMemtag())
+ return true;
+
unsigned Binding = Sym->getBinding();
switch(Binding) {
default:
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-18 09:43:30 +0000