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LibELF: Cache symbol counts + demangled names (userspace only)

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To make repeated symbolication requests faster, we now cache the symbol
count on ELFLoader instead of looking it up in the image each time.

We also cache the demangled versions of names after looking them up the
first time. This is a huge speedup for ProfileViewer. :^)
This commit is contained in:
Andreas Kling 2020-04-07 16:41:42 +02:00
parent 992d8e450c
commit a31ef54a2a
2 changed files with 24 additions and 9 deletions
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26
Libraries/LibELF/ELFLoader.cpp
View file

@ -41,6 +41,7 @@
ELFLoader::ELFLoader(const u8* buffer, size_t size)
: m_image(buffer, size)
{
m_symbol_count = m_image.symbol_count();
}
ELFLoader::~ELFLoader()
@ -152,7 +153,7 @@ char* ELFLoader::symbol_ptr(const char* name)
String ELFLoader::symbolicate(u32 address, u32* out_offset) const
{
if (!m_image.symbol_count()) {
if (!m_symbol_count) {
if (out_offset)
*out_offset = 0;
return "??";
@ -160,14 +161,14 @@ String ELFLoader::symbolicate(u32 address, u32* out_offset) const
SortedSymbol* sorted_symbols = nullptr;
#ifdef KERNEL
if (!m_sorted_symbols_region) {
m_sorted_symbols_region = MM.allocate_kernel_region(PAGE_ROUND_UP(m_image.symbol_count() * sizeof(SortedSymbol)), "Sorted symbols", Kernel::Region::Access::Read | Kernel::Region::Access::Write);
m_sorted_symbols_region = MM.allocate_kernel_region(PAGE_ROUND_UP(m_symbol_count * sizeof(SortedSymbol)), "Sorted symbols", Kernel::Region::Access::Read | Kernel::Region::Access::Write);
sorted_symbols = (SortedSymbol*)m_sorted_symbols_region->vaddr().as_ptr();
size_t index = 0;
m_image.for_each_symbol([&](auto& symbol) {
sorted_symbols[index++] = { symbol.value(), symbol.name() };
return IterationDecision::Continue;
});
quick_sort(sorted_symbols, sorted_symbols + m_image.symbol_count(), [](auto& a, auto& b) {
quick_sort(sorted_symbols, sorted_symbols + m_symbol_count, [](auto& a, auto& b) {
return a.address < b.address;
});
} else {
@ -175,9 +176,9 @@ String ELFLoader::symbolicate(u32 address, u32* out_offset) const
}
#else
if (m_sorted_symbols.is_empty()) {
m_sorted_symbols.ensure_capacity(m_image.symbol_count());
m_sorted_symbols.ensure_capacity(m_symbol_count);
m_image.for_each_symbol([this](auto& symbol) {
m_sorted_symbols.append({ symbol.value(), symbol.name() });
m_sorted_symbols.append({ symbol.value(), symbol.name(), {} });
return IterationDecision::Continue;
});
quick_sort(m_sorted_symbols, [](auto& a, auto& b) {
@ -187,7 +188,7 @@ String ELFLoader::symbolicate(u32 address, u32* out_offset) const
sorted_symbols = m_sorted_symbols.data();
#endif
for (size_t i = 0; i < m_image.symbol_count(); ++i) {
for (size_t i = 0; i < m_symbol_count; ++i) {
if (sorted_symbols[i].address > address) {
if (i == 0) {
if (out_offset)
@ -195,11 +196,20 @@ String ELFLoader::symbolicate(u32 address, u32* out_offset) const
return "!!";
}
auto& symbol = sorted_symbols[i - 1];
#ifdef KERNEL
auto demangled_name = demangle(symbol.name);
#else
auto& demangled_name = symbol.demangled_name;
if (demangled_name.is_null())
demangled_name = demangle(symbol.name);
#endif
if (out_offset) {
*out_offset = address - symbol.address;
return demangle(symbol.name);
return demangled_name;
}
return String::format("%s +%u", demangle(symbol.name).characters(), address - symbol.address);
return String::format("%s +%u", demangled_name.characters(), address - symbol.address);
}
}
if (out_offset)

7
Libraries/LibELF/ELFLoader.h
View file

@ -54,7 +54,7 @@ public:
#endif
char* symbol_ptr(const char* name);
bool has_symbols() const { return m_image.symbol_count(); }
bool has_symbols() const { return m_symbol_count; }
String symbolicate(u32 address, u32* offset = nullptr) const;
@ -78,9 +78,14 @@ private:
};
ELFImage m_image;
size_t m_symbol_count { 0 };
struct SortedSymbol {
u32 address;
StringView name;
#ifndef KERNEL
String demangled_name;
#endif
};
#ifdef KERNEL
mutable OwnPtr<Kernel::Region> m_sorted_symbols_region;