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103 lines
3.9 KiB
C++
103 lines
3.9 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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#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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namespace Debug::Dwarf {
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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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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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auto stream = TRY(FixedMemoryStream::construct(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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TRY(LEB128::read_unsigned(*stream, m_abbreviation_code));
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m_data_offset = TRY(stream->tell());
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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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m_tag = abbreviation_info->tag;
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m_has_children = abbreviation_info->has_children;
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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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ErrorOr<Optional<AttributeValue>> DIE::get_attribute(Attribute const& attribute) const
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{
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auto stream = TRY(FixedMemoryStream::construct(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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auto abbreviation_info = m_compilation_unit.abbreviations_map().get(m_abbreviation_code);
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VERIFY(abbreviation_info);
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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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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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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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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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return {};
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}
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}
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