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AK+Kernel+LibELF: Remove the need for IteratorDecision::Continue

By constraining two implementations, the compiler will select the best
fitting one. All this will require is duplicating the implementation and
simplifying for the `void` case.

This constraining also informs both the caller and compiler by passing
the callback parameter types as part of the constraint
(e.g.: `IterationFunction<int>`).

Some `for_each` functions in LibELF only take functions which return
`void`. This is a minimal correctness check, as it removes one way for a
function to incompletely do something.

There seems to be a possible idiom where inside a lambda, a `return;` is
the same as `continue;` in a for-loop.
This commit is contained in:
Nicholas Baron 2021-05-16 02:36:52 -07:00 committed by GitHub
parent bbaa463032
commit aa4d41fe2c
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
25 changed files with 311 additions and 127 deletions

View file

@ -125,9 +125,8 @@ static Vector<String> get_dependencies(const String& name)
lib->for_each_needed_library([&dependencies, &name](auto needed_name) {
if (name == needed_name)
return IterationDecision::Continue;
return;
dependencies.append(needed_name);
return IterationDecision::Continue;
});
return dependencies;
}

View file

@ -93,7 +93,6 @@ const DynamicObject& DynamicLoader::dynamic_object() const
if (program_header.type() == PT_DYNAMIC) {
dynamic_section_address = VirtualAddress(program_header.raw_data());
}
return IterationDecision::Continue;
});
VERIFY(!dynamic_section_address.is_null());
@ -109,7 +108,6 @@ size_t DynamicLoader::calculate_tls_size() const
if (program_header.type() == PT_TLS) {
tls_size = program_header.size_in_memory();
}
return IterationDecision::Continue;
});
return tls_size;
}
@ -194,7 +192,6 @@ void DynamicLoader::do_main_relocations()
case RelocationResult::Success:
break;
}
return IterationDecision::Continue;
};
m_dynamic_object->relocation_section().for_each_relocation(do_single_relocation);
m_dynamic_object->plt_relocation_section().for_each_relocation(do_single_relocation);
@ -273,7 +270,6 @@ void DynamicLoader::load_program_headers()
VERIFY(!relro_region.has_value());
relro_region = region;
}
return IterationDecision::Continue;
});
VERIFY(!text_regions.is_empty() || !data_regions.is_empty());

View file

@ -49,7 +49,6 @@ void DynamicObject::dump() const
String name_field = String::formatted("({})", name_for_dtag(entry.tag()));
builder.appendff("{:#08x} {:17} {:#08x}\n", entry.tag(), name_field, entry.val());
num_dynamic_sections++;
return IterationDecision::Continue;
});
if (m_has_soname)
@ -171,7 +170,6 @@ void DynamicObject::parse()
VERIFY_NOT_REACHED(); // FIXME: Maybe just break out here and return false?
break;
}
return IterationDecision::Continue;
});
if (!m_size_of_relocation_entry) {

View file

@ -8,6 +8,7 @@
#pragma once
#include <AK/Assertions.h>
#include <AK/Concepts.h>
#include <AK/RefCounted.h>
#include <AK/String.h>
#include <Kernel/VirtualAddress.h>
@ -125,8 +126,11 @@ public:
unsigned relocation_count() const { return entry_count(); }
Relocation relocation(unsigned index) const;
Relocation relocation_at_offset(unsigned offset) const;
template<typename F>
template<IteratorFunction<DynamicObject::Relocation&> F>
void for_each_relocation(F) const;
template<VoidFunction<DynamicObject::Relocation&> F>
void for_each_relocation(F func) const;
};
class Relocation {
@ -251,16 +255,18 @@ public:
ElfW(Half) program_header_count() const;
const ElfW(Phdr) * program_headers() const;
template<typename F>
template<VoidFunction<StringView> F>
void for_each_needed_library(F) const;
template<typename F>
template<VoidFunction<InitializationFunction&> F>
void for_each_initialization_array_function(F f) const;
template<typename F>
template<IteratorFunction<DynamicEntry&> F>
void for_each_dynamic_entry(F) const;
template<VoidFunction<DynamicEntry&> F>
void for_each_dynamic_entry(F func) const;
template<typename F>
template<VoidFunction<Symbol&> F>
void for_each_symbol(F) const;
struct SymbolLookupResult {
@ -341,7 +347,7 @@ private:
// End Section information from DT_* entries
};
template<typename F>
template<IteratorFunction<DynamicObject::Relocation&> F>
inline void DynamicObject::RelocationSection::for_each_relocation(F func) const
{
for (unsigned i = 0; i < relocation_count(); ++i) {
@ -353,16 +359,24 @@ inline void DynamicObject::RelocationSection::for_each_relocation(F func) const
}
}
template<typename F>
template<VoidFunction<DynamicObject::Relocation&> F>
inline void DynamicObject::RelocationSection::for_each_relocation(F func) const
{
for_each_relocation([&](auto& reloc) {
func(reloc);
return IterationDecision::Continue;
});
}
template<VoidFunction<DynamicObject::Symbol&> F>
inline void DynamicObject::for_each_symbol(F func) const
{
for (unsigned i = 0; i < symbol_count(); ++i) {
if (func(symbol(i)) == IterationDecision::Break)
break;
func(symbol(i));
}
}
template<typename F>
template<IteratorFunction<DynamicObject::DynamicEntry&> F>
inline void DynamicObject::for_each_dynamic_entry(F func) const
{
auto* dyns = reinterpret_cast<const ElfW(Dyn)*>(m_dynamic_address.as_ptr());
@ -374,21 +388,29 @@ inline void DynamicObject::for_each_dynamic_entry(F func) const
break;
}
}
template<typename F>
inline void DynamicObject::for_each_needed_library(F func) const
template<VoidFunction<DynamicObject::DynamicEntry&> F>
inline void DynamicObject::for_each_dynamic_entry(F func) const
{
for_each_dynamic_entry([func, this](auto entry) {
if (entry.tag() != DT_NEEDED)
return IterationDecision::Continue;
ElfW(Word) offset = entry.val();
StringView name { (const char*)(m_base_address.offset(m_string_table_offset).offset(offset)).as_ptr() };
if (func(StringView(name)) == IterationDecision::Break)
return IterationDecision::Break;
for_each_dynamic_entry([&](auto& dyn) {
func(dyn);
return IterationDecision::Continue;
});
}
template<typename F>
template<VoidFunction<StringView> F>
inline void DynamicObject::for_each_needed_library(F func) const
{
for_each_dynamic_entry([func, this](auto entry) {
if (entry.tag() != DT_NEEDED)
return;
ElfW(Word) offset = entry.val();
StringView name { (const char*)(m_base_address.offset(m_string_table_offset).offset(offset)).as_ptr() };
func(name);
});
}
template<VoidFunction<DynamicObject::InitializationFunction&> F>
void DynamicObject::for_each_initialization_array_function(F f) const
{
if (!has_init_array_section())

View file

@ -97,7 +97,6 @@ void Image::dump() const
dbgln(" offset: {:x}", program_header.offset());
dbgln(" flags: {:x}", program_header.flags());
dbgln(" }}");
return IterationDecision::Continue;
});
for (unsigned i = 0; i < header().e_shnum; ++i) {
@ -344,7 +343,6 @@ NEVER_INLINE void Image::sort_symbols() const
m_sorted_symbols.ensure_capacity(symbol_count());
for_each_symbol([this](const auto& symbol) {
m_sorted_symbols.append({ symbol.value(), symbol.name(), {}, symbol });
return IterationDecision::Continue;
});
quick_sort(m_sorted_symbols, [](auto& a, auto& b) {
return a.address < b.address;

View file

@ -6,6 +6,7 @@
#pragma once
#include <AK/Concepts.h>
#include <AK/String.h>
#include <AK/Vector.h>
#include <Kernel/VirtualAddress.h>
@ -134,7 +135,8 @@ public:
}
unsigned relocation_count() const { return entry_count(); }
Relocation relocation(unsigned index) const;
template<typename F>
template<VoidFunction<Image::Relocation&> F>
void for_each_relocation(F) const;
};
@ -167,13 +169,24 @@ public:
ProgramHeader program_header(unsigned) const;
FlatPtr program_header_table_offset() const;
template<typename F>
template<IteratorFunction<Image::Section> F>
void for_each_section(F) const;
template<typename F>
template<VoidFunction<Section> F>
void for_each_section(F) const;
template<IteratorFunction<Section&> F>
void for_each_section_of_type(unsigned, F) const;
template<typename F>
template<VoidFunction<Section&> F>
void for_each_section_of_type(unsigned, F) const;
template<IteratorFunction<Symbol> F>
void for_each_symbol(F) const;
template<typename F>
template<VoidFunction<Symbol> F>
void for_each_symbol(F) const;
template<IteratorFunction<ProgramHeader> F>
void for_each_program_header(F func) const;
template<VoidFunction<ProgramHeader> F>
void for_each_program_header(F) const;
Optional<Section> lookup_section(String const& name) const;
@ -222,15 +235,26 @@ private:
mutable Vector<SortedSymbol> m_sorted_symbols;
};
template<typename F>
template<IteratorFunction<Image::Section> F>
inline void Image::for_each_section(F func) const
{
auto section_count = this->section_count();
for (unsigned i = 0; i < section_count; ++i)
func(section(i));
for (unsigned i = 0; i < section_count; ++i) {
if (func(section(i)) == IterationDecision::Break)
break;
}
}
template<typename F>
template<VoidFunction<Image::Section> F>
inline void Image::for_each_section(F func) const
{
for_each_section([&](auto section) {
func(move(section));
return IterationDecision::Continue;
});
}
template<IteratorFunction<Image::Section&> F>
inline void Image::for_each_section_of_type(unsigned type, F func) const
{
auto section_count = this->section_count();
@ -243,17 +267,25 @@ inline void Image::for_each_section_of_type(unsigned type, F func) const
}
}
template<typename F>
template<VoidFunction<Image::Section&> F>
inline void Image::for_each_section_of_type(unsigned type, F func) const
{
for_each_section_of_type(type, [&](auto& section) {
func(section);
return IterationDecision::Continue;
});
}
template<VoidFunction<Image::Relocation&> F>
inline void Image::RelocationSection::for_each_relocation(F func) const
{
auto relocation_count = this->relocation_count();
for (unsigned i = 0; i < relocation_count; ++i) {
if (func(relocation(i)) == IterationDecision::Break)
break;
func(relocation(i));
}
}
template<typename F>
template<IteratorFunction<Image::Symbol> F>
inline void Image::for_each_symbol(F func) const
{
auto symbol_count = this->symbol_count();
@ -263,14 +295,32 @@ inline void Image::for_each_symbol(F func) const
}
}
template<typename F>
template<VoidFunction<Image::Symbol> F>
inline void Image::for_each_symbol(F func) const
{
for_each_symbol([&](auto symbol) {
func(move(symbol));
return IterationDecision::Continue;
});
}
template<IteratorFunction<Image::ProgramHeader> F>
inline void Image::for_each_program_header(F func) const
{
auto program_header_count = this->program_header_count();
for (unsigned i = 0; i < program_header_count; ++i) {
if (func(program_header(i)) == IterationDecision::Break)
return;
break;
}
}
template<VoidFunction<Image::ProgramHeader> F>
inline void Image::for_each_program_header(F func) const
{
for_each_program_header([&](auto header) {
func(move(header));
return IterationDecision::Continue;
});
}
} // end namespace ELF