Support dwarf fission for wasm object files

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.
It also splits the import-preparation step into its own function (and skips it when writing a dwo).

Differential Revision: https://reviews.llvm.org/D85685

1 files changed, 35 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index 0660780..ae7345c 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -796,6 +796,10 @@ void MCObjectFileInfo::initWasmMCObjectFileInfo(const Triple &T) {
   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());
 
   DwarfDebugNamesSection =
       Ctx->getWasmSection(".debug_names", SectionKind::getMetadata());
@@ -808,6 +812,37 @@ void MCObjectFileInfo::initWasmMCObjectFileInfo(const Triple &T) {
   DwarfLoclistsSection =
       Ctx->getWasmSection(".debug_loclists", SectionKind::getMetadata());
 
+  // Fission Sections
+  DwarfInfoDWOSection =
+      Ctx->getWasmSection(".debug_info.dwo", SectionKind::getMetadata());
+  DwarfTypesDWOSection =
+      Ctx->getWasmSection(".debug_types.dwo", SectionKind::getMetadata());
+  DwarfAbbrevDWOSection =
+      Ctx->getWasmSection(".debug_abbrev.dwo", SectionKind::getMetadata());
+  DwarfStrDWOSection =
+      Ctx->getWasmSection(".debug_str.dwo", SectionKind::getMetadata());
+  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());
+  DwarfRnglistsDWOSection =
+      Ctx->getWasmSection(".debug_rnglists.dwo", SectionKind::getMetadata());
+  DwarfMacinfoDWOSection =
+      Ctx->getWasmSection(".debug_macinfo.dwo", SectionKind::getMetadata());
+  DwarfMacroDWOSection =
+      Ctx->getWasmSection(".debug_macro.dwo", SectionKind::getMetadata());
+
+  DwarfLoclistsDWOSection =
+      Ctx->getWasmSection(".debug_loclists.dwo", SectionKind::getMetadata());
+
+  // DWP Sections
+  DwarfCUIndexSection =
+      Ctx->getWasmSection(".debug_cu_index", SectionKind::getMetadata(), 0);
+  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.