dschuff created this revision.
dschuff added reviewers: sbc100, aardappel.
Herald added subscribers: llvm-commits, cfe-commits, sunfish, hiraditya,
aprantl.
Herald added projects: clang, LLVM.
dschuff requested review of this revision.
Herald added a subscriber: aheejin.
Initial support for dwarf fission sections (-gsplit-dwarf) on wasm.
The most interesting change is support for writing 2 files (.o and .dwo) in the
wasm object writer. My approach moves object-writing logic into its own function
and calls it twice, swapping out the endian::Writer (W) in between calls.
(This is a bit different than the ELF writer's approach. I like it a bit better
but don't have a strong opinion).
This patch has the basic structure and writes separate files containing
non-dwo and dwo sections. There are couple of other things needed:
1. Linker support for an equivalent of ELF's SHF_EXCLUDE to keep the debug
sections from being linked
2. a few checks and validations (equivalent to the places where the ELF object
writer checks the dwo mode, such as validating relocs)
These can go in future CLs, but I still need to add some tests to this one.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D85685
Files:
clang/lib/Driver/ToolChains/Clang.cpp
llvm/lib/MC/MCAsmBackend.cpp
llvm/lib/MC/MCObjectFileInfo.cpp
llvm/lib/MC/WasmObjectWriter.cpp
Index: llvm/lib/MC/WasmObjectWriter.cpp
===================================================================
--- llvm/lib/MC/WasmObjectWriter.cpp
+++ llvm/lib/MC/WasmObjectWriter.cpp
@@ -270,8 +270,8 @@
DwoOnly,
};
bool IsSplitDwarf = false;
- raw_pwrite_stream* OS = nullptr;
- raw_pwrite_stream* DwoOS = nullptr;
+ raw_pwrite_stream *OS = nullptr;
+ raw_pwrite_stream *DwoOS = nullptr;
// TargetObjectWriter wranppers.
bool is64Bit() const { return TargetObjectWriter->is64Bit(); }
@@ -287,9 +287,8 @@
: TargetObjectWriter(std::move(MOTW)), OS(&OS_) {}
WasmObjectWriter(std::unique_ptr<MCWasmObjectTargetWriter> MOTW,
raw_pwrite_stream &OS_, raw_pwrite_stream &DwoOS_)
- : TargetObjectWriter(std::move(MOTW)),
- IsSplitDwarf(true), OS(&OS_), DwoOS(&DwoOS_) {}
-
+ : TargetObjectWriter(std::move(MOTW)), IsSplitDwarf(true), OS(&OS_),
+ DwoOS(&DwoOS_) {}
private:
void reset() override {
@@ -324,8 +323,8 @@
uint64_t writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) override;
- uint64_t writeOneObject(MCAssembler &Asm, const MCAsmLayout &Layout, DwoMode Mode);
-
+ uint64_t writeOneObject(MCAssembler &Asm, const MCAsmLayout &Layout,
+ DwoMode Mode);
void writeString(const StringRef Str) {
encodeULEB128(Str.size(), W->OS);
@@ -781,7 +780,7 @@
break;
case wasm::WASM_EXTERNAL_MEMORY:
encodeULEB128(Import.Memory.Flags, W->OS);
- encodeULEB128(NumPages, W->OS); // initial
+ encodeULEB128(NumPages, W->OS); // initial
break;
case wasm::WASM_EXTERNAL_TABLE:
W->OS << char(Import.Table.ElemType);
@@ -961,8 +960,8 @@
encodeULEB128(0, W->OS); // memory index
if ((Segment.InitFlags & wasm::WASM_SEGMENT_IS_PASSIVE) == 0) {
W->OS << char(Segment.Offset > std::numeric_limits<int32_t>().max()
- ? wasm::WASM_OPCODE_I64_CONST
- : wasm::WASM_OPCODE_I32_CONST);
+ ? wasm::WASM_OPCODE_I64_CONST
+ : wasm::WASM_OPCODE_I32_CONST);
encodeSLEB128(Segment.Offset, W->OS); // offset
W->OS << char(wasm::WASM_OPCODE_END);
}
@@ -1771,6 +1770,7 @@
std::unique_ptr<MCObjectWriter>
llvm::createWasmDwoObjectWriter(std::unique_ptr<MCWasmObjectTargetWriter> MOTW,
- raw_pwrite_stream &OS, raw_pwrite_stream &DwoOS) {
+ raw_pwrite_stream &OS,
+ raw_pwrite_stream &DwoOS) {
return std::make_unique<WasmObjectWriter>(std::move(MOTW), OS);
}
Index: llvm/lib/MC/MCObjectFileInfo.cpp
===================================================================
--- llvm/lib/MC/MCObjectFileInfo.cpp
+++ llvm/lib/MC/MCObjectFileInfo.cpp
@@ -796,8 +796,10 @@
DwarfFrameSection = Ctx->getWasmSection(".debug_frame", SectionKind::getMetadata());
DwarfPubNamesSection = Ctx->getWasmSection(".debug_pubnames", SectionKind::getMetadata());
DwarfPubTypesSection = Ctx->getWasmSection(".debug_pubtypes", SectionKind::getMetadata());
- DwarfGnuPubNamesSection = Ctx->getWasmSection(".debug_gnu_pubnames", SectionKind::getMetadata());
- DwarfGnuPubTypesSection = Ctx->getWasmSection(".debug_gnu_pubtypes", SectionKind::getMetadata());
+ DwarfGnuPubNamesSection =
+ Ctx->getWasmSection(".debug_gnu_pubnames", SectionKind::getMetadata());
+ DwarfGnuPubTypesSection =
+ Ctx->getWasmSection(".debug_gnu_pubtypes", SectionKind::getMetadata());
DwarfDebugNamesSection =
Ctx->getWasmSection(".debug_names", SectionKind::getMetadata());
@@ -817,15 +819,15 @@
Ctx->getWasmSection(".debug_types.dwo", SectionKind::getMetadata());
DwarfAbbrevDWOSection =
Ctx->getWasmSection(".debug_abbrev.dwo", SectionKind::getMetadata());
- DwarfStrDWOSection = Ctx->getWasmSection(
- ".debug_str.dwo", SectionKind::getMetadata());
- //ELF::SHF_MERGE | ELF::SHF_STRINGS | ELF::SHF_EXCLUDE, 1, "");
+ DwarfStrDWOSection =
+ Ctx->getWasmSection(".debug_str.dwo", SectionKind::getMetadata());
+ // ELF::SHF_MERGE | ELF::SHF_STRINGS | ELF::SHF_EXCLUDE, 1, "");
DwarfLineDWOSection =
Ctx->getWasmSection(".debug_line.dwo", SectionKind::getMetadata());
DwarfLocDWOSection =
Ctx->getWasmSection(".debug_loc.dwo", SectionKind::getMetadata());
- DwarfStrOffDWOSection = Ctx->getWasmSection(".debug_str_offsets.dwo",
- SectionKind::getMetadata());
+ DwarfStrOffDWOSection =
+ Ctx->getWasmSection(".debug_str_offsets.dwo", SectionKind::getMetadata());
DwarfRnglistsDWOSection =
Ctx->getWasmSection(".debug_rnglists.dwo", SectionKind::getMetadata());
DwarfMacinfoDWOSection =
@@ -842,7 +844,6 @@
DwarfTUIndexSection =
Ctx->getWasmSection(".debug_tu_index", SectionKind::getMetadata(), 0);
-
// Wasm use data section for LSDA.
// TODO Consider putting each function's exception table in a separate
// section, as in -function-sections, to facilitate lld's --gc-section.
Index: llvm/lib/MC/MCAsmBackend.cpp
===================================================================
--- llvm/lib/MC/MCAsmBackend.cpp
+++ llvm/lib/MC/MCAsmBackend.cpp
@@ -55,16 +55,16 @@
raw_pwrite_stream &DwoOS) const {
auto TW = createObjectTargetWriter();
switch (TW->getFormat()) {
- case Triple::ELF:
- return createELFDwoObjectWriter(cast<MCELFObjectTargetWriter>(std::move(TW)),
- OS, DwoOS, Endian == support::little);
- case Triple::Wasm:
- return createWasmDwoObjectWriter(cast<MCWasmObjectTargetWriter>(std::move(TW)),
- OS, DwoOS);
- default:
- report_fatal_error("dwo only supported with ELF");
+ case Triple::ELF:
+ return createELFDwoObjectWriter(
+ cast<MCELFObjectTargetWriter>(std::move(TW)), OS, DwoOS,
+ Endian == support::little);
+ case Triple::Wasm:
+ return createWasmDwoObjectWriter(
+ cast<MCWasmObjectTargetWriter>(std::move(TW)), OS, DwoOS);
+ default:
+ report_fatal_error("dwo only supported with ELF");
}
-
}
Optional<MCFixupKind> MCAsmBackend::getFixupKind(StringRef Name) const {
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -4765,7 +4765,8 @@
// Add the split debug info name to the command lines here so we
// can propagate it to the backend.
bool SplitDWARF = (DwarfFission != DwarfFissionKind::None) &&
- (TC.getTriple().isOSBinFormatELF() || TC.getTriple().isOSBinFormatWasm()) &&
+ (TC.getTriple().isOSBinFormatELF() ||
+ TC.getTriple().isOSBinFormatWasm()) &&
(isa<AssembleJobAction>(JA) || isa<CompileJobAction>(JA) ||
isa<BackendJobAction>(JA));
if (SplitDWARF) {
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
