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LibELF: Save the negative TLS offset in m_tls_offset

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This makes it unnecessary to track the symbol size which just isn't
available for unexported symbols (e.g. for 'static __thread').
This commit is contained in:
Gunnar Beutner 2021-07-04 00:01:06 +02:00 • committed by Andreas Kling
parent a0a38e1e84
commit 5f6ee4c539
4 changed files with 8 additions and 8 deletions
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2
Userland/Libraries/LibELF/DynamicLinker.cpp
View file

@ -91,8 +91,8 @@ static Result<NonnullRefPtr<DynamicLoader>, DlErrorMessage> map_library(const St
s_loaders.set(get_library_name(filename), *loader); s_loaders.set(get_library_name(filename), *loader);
s_current_tls_offset -= loader->tls_size_of_current_object();
loader->set_tls_offset(s_current_tls_offset); loader->set_tls_offset(s_current_tls_offset);
s_current_tls_offset += loader->tls_size_of_current_object();
return loader; return loader;
} }

9
Userland/Libraries/LibELF/DynamicLoader.cpp
View file

@ -490,7 +490,7 @@ DynamicLoader::RelocationResult DynamicLoader::do_relocation(const ELF::DynamicO
break; break;
auto* dynamic_object_of_symbol = res.value().dynamic_object; auto* dynamic_object_of_symbol = res.value().dynamic_object;
VERIFY(dynamic_object_of_symbol); VERIFY(dynamic_object_of_symbol);
*patch_ptr = negative_offset_from_tls_block_end(res.value().value, dynamic_object_of_symbol->tls_offset().value(), res.value().size); *patch_ptr = negative_offset_from_tls_block_end(res.value().value, dynamic_object_of_symbol->tls_offset().value());
break; break;
} }
#ifndef __LP64__ #ifndef __LP64__
@ -519,10 +519,9 @@ DynamicLoader::RelocationResult DynamicLoader::do_relocation(const ELF::DynamicO
return RelocationResult::Success; return RelocationResult::Success;
} }
ssize_t DynamicLoader::negative_offset_from_tls_block_end(size_t value_of_symbol, size_t tls_offset, size_t symbol_size) const ssize_t DynamicLoader::negative_offset_from_tls_block_end(size_t value_of_symbol, ssize_t tls_offset) const
{ {
VERIFY(symbol_size > 0); ssize_t offset = static_cast<ssize_t>(tls_offset + value_of_symbol);
ssize_t offset = -static_cast<ssize_t>(value_of_symbol + tls_offset + symbol_size);
// At offset 0 there's the thread's ThreadSpecificData structure, we don't want to collide with it. // At offset 0 there's the thread's ThreadSpecificData structure, we don't want to collide with it.
VERIFY(offset < 0); VERIFY(offset < 0);
return offset; return offset;
@ -549,7 +548,7 @@ void DynamicLoader::copy_initial_tls_data_into(ByteBuffer& buffer) const
if (symbol.type() != STT_TLS) if (symbol.type() != STT_TLS)
return IterationDecision::Continue; return IterationDecision::Continue;
ssize_t negative_offset = negative_offset_from_tls_block_end(symbol.value(), m_tls_offset, symbol.size()); ssize_t negative_offset = negative_offset_from_tls_block_end(symbol.value(), m_tls_offset);
VERIFY(symbol.size() != 0); VERIFY(symbol.size() != 0);
VERIFY(buffer.size() + negative_offset + symbol.size() <= buffer.size()); VERIFY(buffer.size() + negative_offset + symbol.size() <= buffer.size());
memcpy(buffer.data() + buffer.size() + negative_offset, tls_data + symbol.value(), symbol.size()); memcpy(buffer.data() + buffer.size() + negative_offset, tls_data + symbol.value(), symbol.size());

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

@ -131,7 +131,7 @@ private:
}; };
RelocationResult do_relocation(const DynamicObject::Relocation&, ShouldInitializeWeak should_initialize_weak); RelocationResult do_relocation(const DynamicObject::Relocation&, ShouldInitializeWeak should_initialize_weak);
size_t calculate_tls_size() const; size_t calculate_tls_size() const;
ssize_t negative_offset_from_tls_block_end(size_t value_of_symbol, size_t tls_offset, size_t symbol_size) const; ssize_t negative_offset_from_tls_block_end(size_t value_of_symbol, ssize_t tls_offset) const;
String m_filename; String m_filename;
String m_program_interpreter; String m_program_interpreter;
@ -151,7 +151,7 @@ private:
VirtualAddress m_dynamic_section_address; VirtualAddress m_dynamic_section_address;
size_t m_tls_offset { 0 }; ssize_t m_tls_offset { 0 };
size_t m_tls_size_of_current_object { 0 }; size_t m_tls_size_of_current_object { 0 };
Vector<DynamicObject::Relocation> m_unresolved_relocations; Vector<DynamicObject::Relocation> m_unresolved_relocations;

1
Userland/Libraries/LibELF/DynamicObject.h
View file

@ -195,6 +195,7 @@ public:
return m_dynamic.base_address().offset(offset()); return m_dynamic.base_address().offset(offset());
return VirtualAddress { offset() }; return VirtualAddress { offset() };
} }
[[nodiscard]] DynamicObject const& dynamic_object() const { return m_dynamic; }
private: private:
const DynamicObject& m_dynamic; const DynamicObject& m_dynamic;