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			103 lines
		
	
	
	
		
			3.8 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			103 lines
		
	
	
	
		
			3.8 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2020-2021, Itamar S. <itamar8910@gmail.com>
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|  *
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|  * SPDX-License-Identifier: BSD-2-Clause
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|  */
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| 
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| #include "DIE.h"
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| #include "CompilationUnit.h"
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| #include "DwarfInfo.h"
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| #include <AK/ByteBuffer.h>
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| #include <AK/LEB128.h>
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| #include <AK/MemoryStream.h>
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| 
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| namespace Debug::Dwarf {
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| 
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| DIE::DIE(CompilationUnit const& unit, u32 offset, Optional<u32> parent_offset)
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|     : m_compilation_unit(unit)
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| {
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|     rehydrate_from(offset, parent_offset).release_value_but_fixme_should_propagate_errors();
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| }
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| 
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| ErrorOr<void> DIE::rehydrate_from(u32 offset, Optional<u32> parent_offset)
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| {
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|     m_offset = offset;
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| 
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|     FixedMemoryStream stream { m_compilation_unit.dwarf_info().debug_info_data() };
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|     // Note: We can't just slice away from the input data here, since get_attribute_value will try to recover the original offset using seek().
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|     TRY(stream.seek(m_offset));
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|     m_abbreviation_code = TRY(stream.read_value<LEB128<size_t>>());
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|     m_data_offset = TRY(stream.tell());
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| 
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|     if (m_abbreviation_code == 0) {
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|         // An abbreviation code of 0 ( = null DIE entry) means the end of a chain of siblings
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|         m_tag = EntryTag::None;
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|     } else {
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|         auto abbreviation_info = m_compilation_unit.abbreviations_map().get(m_abbreviation_code);
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|         VERIFY(abbreviation_info);
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| 
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|         m_tag = abbreviation_info->tag;
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|         m_has_children = abbreviation_info->has_children;
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| 
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|         // We iterate the attributes data only to calculate this DIE's size
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|         for (auto& attribute_spec : abbreviation_info->attribute_specifications) {
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|             TRY(m_compilation_unit.dwarf_info().get_attribute_value(attribute_spec.form, attribute_spec.value, stream, &m_compilation_unit));
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|         }
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|     }
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|     m_size = TRY(stream.tell()) - m_offset;
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|     m_parent_offset = parent_offset;
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|     return {};
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| }
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| 
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| ErrorOr<Optional<AttributeValue>> DIE::get_attribute(Attribute const& attribute) const
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| {
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|     FixedMemoryStream stream { m_compilation_unit.dwarf_info().debug_info_data() };
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|     // Note: We can't just slice away from the input data here, since get_attribute_value will try to recover the original offset using seek().
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|     TRY(stream.seek(m_data_offset));
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| 
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|     auto abbreviation_info = m_compilation_unit.abbreviations_map().get(m_abbreviation_code);
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|     VERIFY(abbreviation_info);
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| 
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|     for (auto const& attribute_spec : abbreviation_info->attribute_specifications) {
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|         auto value = TRY(m_compilation_unit.dwarf_info().get_attribute_value(attribute_spec.form, attribute_spec.value, stream, &m_compilation_unit));
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|         if (attribute_spec.attribute == attribute) {
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|             return value;
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|         }
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|     }
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|     return Optional<AttributeValue> {};
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| }
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| 
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| ErrorOr<void> DIE::for_each_child(Function<ErrorOr<void>(DIE const& child)> callback) const
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| {
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|     if (!m_has_children)
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|         return {};
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| 
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|     auto current_child = DIE(m_compilation_unit, m_offset + m_size, m_offset);
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|     while (true) {
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|         TRY(callback(current_child));
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|         if (current_child.is_null())
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|             break;
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|         if (!current_child.has_children()) {
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|             TRY(current_child.rehydrate_from(current_child.offset() + current_child.size(), m_offset));
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|             continue;
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|         }
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| 
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|         auto sibling = TRY(current_child.get_attribute(Attribute::Sibling));
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|         u32 sibling_offset = 0;
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|         if (sibling.has_value()) {
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|             sibling_offset = sibling.value().as_unsigned();
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|         } else {
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|             // NOTE: According to the spec, the compiler doesn't have to supply the sibling information.
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|             // When it doesn't, we have to recursively iterate the current child's children to find where they end
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|             TRY(current_child.for_each_child([&](DIE const& sub_child) -> ErrorOr<void> {
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|                 sibling_offset = sub_child.offset() + sub_child.size();
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|                 return {};
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|             }));
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|         }
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|         TRY(current_child.rehydrate_from(sibling_offset, m_offset));
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|     }
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| 
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|     return {};
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| }
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| 
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| }
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