Reduce the size of native debug info generated by JIT.
Remove some ELF file overheads:
- Do not produce program headers.
- Do not page align strtab.
- Do not write oat_patches sections.
This more than halves the size of JIT native debug info.
Since we generate many small entries, the overheads added up.
Change-Id: I27d95548c61e2e38c3683d6f5eb870a2db6e812d
diff --git a/compiler/elf_writer_debug.cc b/compiler/elf_writer_debug.cc
index d1f5007..ca8cd68 100644
--- a/compiler/elf_writer_debug.cc
+++ b/compiler/elf_writer_debug.cc
@@ -1148,13 +1148,19 @@
writer.Write(types);
}
- void End() {
+ void End(bool write_oat_patches) {
builder_->GetDebugInfo()->End();
- builder_->WritePatches(".debug_info.oat_patches",
- ArrayRef<const uintptr_t>(debug_info_patches_));
+ if (write_oat_patches) {
+ builder_->WritePatches(".debug_info.oat_patches",
+ ArrayRef<const uintptr_t>(debug_info_patches_));
+ }
builder_->WriteSection(".debug_abbrev", &debug_abbrev_buffer_);
- builder_->WriteSection(".debug_loc", &debug_loc_);
- builder_->WriteSection(".debug_ranges", &debug_ranges_);
+ if (!debug_loc_.empty()) {
+ builder_->WriteSection(".debug_loc", &debug_loc_);
+ }
+ if (!debug_ranges_.empty()) {
+ builder_->WriteSection(".debug_ranges", &debug_ranges_);
+ }
}
private:
@@ -1357,10 +1363,12 @@
return buffer.size();
}
- void End() {
+ void End(bool write_oat_patches) {
builder_->GetDebugLine()->End();
- builder_->WritePatches(".debug_line.oat_patches",
- ArrayRef<const uintptr_t>(debug_line_patches));
+ if (write_oat_patches) {
+ builder_->WritePatches(".debug_line.oat_patches",
+ ArrayRef<const uintptr_t>(debug_line_patches));
+ }
}
private:
@@ -1370,7 +1378,8 @@
template<typename ElfTypes>
static void WriteDebugSections(ElfBuilder<ElfTypes>* builder,
- const ArrayRef<const MethodDebugInfo>& method_infos) {
+ const ArrayRef<const MethodDebugInfo>& method_infos,
+ bool write_oat_patches) {
// Group the methods into compilation units based on source file.
std::vector<CompilationUnit> compilation_units;
const char* last_source_file = nullptr;
@@ -1394,7 +1403,7 @@
for (auto& compilation_unit : compilation_units) {
line_writer.WriteCompilationUnit(compilation_unit);
}
- line_writer.End();
+ line_writer.End(write_oat_patches);
}
// Write .debug_info section.
@@ -1404,7 +1413,7 @@
for (const auto& compilation_unit : compilation_units) {
info_writer.WriteCompilationUnit(compilation_unit);
}
- info_writer.End();
+ info_writer.End(write_oat_patches);
}
}
@@ -1484,13 +1493,14 @@
template <typename ElfTypes>
void WriteDebugInfo(ElfBuilder<ElfTypes>* builder,
const ArrayRef<const MethodDebugInfo>& method_infos,
- CFIFormat cfi_format) {
+ CFIFormat cfi_format,
+ bool write_oat_patches) {
// Add methods to .symtab.
WriteDebugSymbols(builder, method_infos, true /* with_signature */);
// Generate CFI (stack unwinding information).
- WriteCFISection(builder, method_infos, cfi_format, true /* write_oat_patches */);
+ WriteCFISection(builder, method_infos, cfi_format, write_oat_patches);
// Write DWARF .debug_* sections.
- WriteDebugSections(builder, method_infos);
+ WriteDebugSections(builder, method_infos, write_oat_patches);
}
static void XzCompress(const std::vector<uint8_t>* src, std::vector<uint8_t>* dst) {
@@ -1571,10 +1581,12 @@
buffer.reserve(KB);
VectorOutputStream out("Debug ELF file", &buffer);
std::unique_ptr<ElfBuilder<ElfTypes>> builder(new ElfBuilder<ElfTypes>(isa, &out));
- builder->Start();
+ // No program headers since the ELF file is not linked and has no allocated sections.
+ builder->Start(false /* write_program_headers */);
WriteDebugInfo(builder.get(),
ArrayRef<const MethodDebugInfo>(&method_info, 1),
- DW_DEBUG_FRAME_FORMAT);
+ DW_DEBUG_FRAME_FORMAT,
+ false /* write_oat_patches */);
builder->End();
CHECK(builder->Good());
// Make a copy of the buffer. We want to shrink it anyway.
@@ -1601,12 +1613,12 @@
buffer.reserve(KB);
VectorOutputStream out("Debug ELF file", &buffer);
std::unique_ptr<ElfBuilder<ElfTypes>> builder(new ElfBuilder<ElfTypes>(isa, &out));
- builder->Start();
-
+ // No program headers since the ELF file is not linked and has no allocated sections.
+ builder->Start(false /* write_program_headers */);
DebugInfoWriter<ElfTypes> info_writer(builder.get());
info_writer.Start();
info_writer.WriteTypes(types);
- info_writer.End();
+ info_writer.End(false /* write_oat_patches */);
builder->End();
CHECK(builder->Good());
@@ -1630,11 +1642,13 @@
template void WriteDebugInfo<ElfTypes32>(
ElfBuilder<ElfTypes32>* builder,
const ArrayRef<const MethodDebugInfo>& method_infos,
- CFIFormat cfi_format);
+ CFIFormat cfi_format,
+ bool write_oat_patches);
template void WriteDebugInfo<ElfTypes64>(
ElfBuilder<ElfTypes64>* builder,
const ArrayRef<const MethodDebugInfo>& method_infos,
- CFIFormat cfi_format);
+ CFIFormat cfi_format,
+ bool write_oat_patches);
template void WriteMiniDebugInfo<ElfTypes32>(
ElfBuilder<ElfTypes32>* builder,
const ArrayRef<const MethodDebugInfo>& method_infos);