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LibELF + LibDebug: Reduce allocations during symbolification

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Avoid promotion of static strings to AK::String, instead use
AK::StringView and operator ""sv, to force string view's instead
which avoids allocation of String. This code path isn't hot enough
that it makes a huge difference, but every bit counts.
This commit is contained in:
Brian Gianforcaro 2021-05-30 23:44:02 -07:00 • committed by Ali Mohammad Pur
parent 35a97884aa
commit 5bfba3f789
5 changed files with 12 additions and 12 deletions
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4
Userland/Libraries/LibDebug/DebugInfo.cpp
View file

@ -17,7 +17,7 @@ namespace Debug {
DebugInfo::DebugInfo(NonnullOwnPtr<const ELF::Image> elf, String source_root, FlatPtr base_address) DebugInfo::DebugInfo(NonnullOwnPtr<const ELF::Image> elf, String source_root, FlatPtr base_address)
: m_elf(move(elf)) : m_elf(move(elf))
, m_source_root(source_root) , m_source_root(move(source_root))
, m_base_address(base_address) , m_base_address(base_address)
, m_dwarf_info(*m_elf) , m_dwarf_info(*m_elf)
{ {
@ -78,7 +78,7 @@ void DebugInfo::parse_scopes_impl(const Dwarf::DIE& die)
void DebugInfo::prepare_lines() void DebugInfo::prepare_lines()
{ {
auto section = elf().lookup_section(".debug_line"); auto section = elf().lookup_section(".debug_line"sv);
if (!section.has_value()) if (!section.has_value())
return; return;

10
Userland/Libraries/LibDebug/Dwarf/DwarfInfo.cpp
View file

@ -13,15 +13,15 @@ namespace Debug::Dwarf {
DwarfInfo::DwarfInfo(const ELF::Image& elf) DwarfInfo::DwarfInfo(const ELF::Image& elf)
: m_elf(elf) : m_elf(elf)
{ {
m_debug_info_data = section_data(".debug_info"); m_debug_info_data = section_data(".debug_info"sv);
m_abbreviation_data = section_data(".debug_abbrev"); m_abbreviation_data = section_data(".debug_abbrev"sv);
m_debug_strings_data = section_data(".debug_str"); m_debug_strings_data = section_data(".debug_str"sv);
m_debug_line_strings_data = section_data(".debug_line_str"); m_debug_line_strings_data = section_data(".debug_line_str"sv);
populate_compilation_units(); populate_compilation_units();
} }
ReadonlyBytes DwarfInfo::section_data(const String& section_name) const ReadonlyBytes DwarfInfo::section_data(const StringView& section_name) const
{ {
auto section = m_elf.lookup_section(section_name); auto section = m_elf.lookup_section(section_name);
if (!section.has_value()) if (!section.has_value())

2
Userland/Libraries/LibDebug/Dwarf/DwarfInfo.h
View file

@ -60,7 +60,7 @@ public:
private: private:
void populate_compilation_units(); void populate_compilation_units();
ReadonlyBytes section_data(const String& section_name) const; ReadonlyBytes section_data(const StringView& section_name) const;
const ELF::Image& m_elf; const ELF::Image& m_elf;
ReadonlyBytes m_debug_info_data; ReadonlyBytes m_debug_info_data;

4
Userland/Libraries/LibELF/Image.cpp
View file

@ -271,7 +271,7 @@ Optional<Image::RelocationSection> Image::Section::relocations() const
return static_cast<RelocationSection>(relocation_section.value()); return static_cast<RelocationSection>(relocation_section.value());
} }
Optional<Image::Section> Image::lookup_section(const String& name) const Optional<Image::Section> Image::lookup_section(const StringView& name) const
{ {
VERIFY(m_valid); VERIFY(m_valid);
for (unsigned i = 0; i < section_count(); ++i) { for (unsigned i = 0; i < section_count(); ++i) {
@ -288,7 +288,7 @@ StringView Image::Symbol::raw_data() const
return { section.raw_data() + (value() - section.address()), size() }; return { section.raw_data() + (value() - section.address()), size() };
} }
Optional<Image::Symbol> Image::find_demangled_function(const String& name) const Optional<Image::Symbol> Image::find_demangled_function(const StringView& name) const
{ {
Optional<Image::Symbol> found; Optional<Image::Symbol> found;
for_each_symbol([&](const Image::Symbol& symbol) { for_each_symbol([&](const Image::Symbol& symbol) {

4
Userland/Libraries/LibELF/Image.h
View file

@ -189,7 +189,7 @@ public:
template<VoidFunction<ProgramHeader> F> template<VoidFunction<ProgramHeader> F>
void for_each_program_header(F) const; void for_each_program_header(F) const;
Optional<Section> lookup_section(String const& name) const; Optional<Section> lookup_section(StringView const& name) const;
bool is_executable() const { return header().e_type == ET_EXEC; } bool is_executable() const { return header().e_type == ET_EXEC; }
bool is_relocatable() const { return header().e_type == ET_REL; } bool is_relocatable() const { return header().e_type == ET_REL; }
@ -199,7 +199,7 @@ public:
FlatPtr base_address() const { return (FlatPtr)m_buffer; } FlatPtr base_address() const { return (FlatPtr)m_buffer; }
size_t size() const { return m_size; } size_t size() const { return m_size; }
Optional<Symbol> find_demangled_function(const String& name) const; Optional<Symbol> find_demangled_function(const StringView& name) const;
bool has_symbols() const { return symbol_count(); } bool has_symbols() const { return symbol_count(); }
String symbolicate(u32 address, u32* offset = nullptr) const; String symbolicate(u32 address, u32* offset = nullptr) const;