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8e5b70a0ba
This will be needed when we add `DW_FORM_strx*` and `DW_FORM_addrx*` support, which requires us to fetch `DW_AT_str_offsets_base` and `DW_AT_addr_base` attributes from the parent compilation unit. This can't be done as we read the values, because it would create infinite recursion (as we might try to parse the compilation unit's `DW_FORM_strx*` encoded name before we get to the attribute). Having getters ensures that we will perform lookups if they are needed.
460 lines
17 KiB
C++
460 lines
17 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 "DebugInfo.h"
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#include <AK/Debug.h>
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#include <AK/LexicalPath.h>
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#include <AK/MemoryStream.h>
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#include <AK/QuickSort.h>
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#include <LibDebug/Dwarf/CompilationUnit.h>
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#include <LibDebug/Dwarf/DwarfInfo.h>
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#include <LibDebug/Dwarf/Expression.h>
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namespace Debug {
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DebugInfo::DebugInfo(ELF::Image const& elf, String source_root, FlatPtr base_address)
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: m_elf(elf)
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, m_source_root(move(source_root))
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, m_base_address(base_address)
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, m_dwarf_info(m_elf)
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{
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prepare_variable_scopes();
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prepare_lines();
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}
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void DebugInfo::prepare_variable_scopes()
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{
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m_dwarf_info.for_each_compilation_unit([&](Dwarf::CompilationUnit const& unit) {
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auto root = unit.root_die();
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parse_scopes_impl(root);
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});
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}
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void DebugInfo::parse_scopes_impl(Dwarf::DIE const& die)
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{
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die.for_each_child([&](Dwarf::DIE const& child) {
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if (child.is_null())
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return;
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if (!(child.tag() == Dwarf::EntryTag::SubProgram || child.tag() == Dwarf::EntryTag::LexicalBlock))
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return;
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if (child.get_attribute(Dwarf::Attribute::Inline).has_value()) {
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dbgln_if(SPAM_DEBUG, "DWARF inlined functions are not supported");
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return;
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}
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if (child.get_attribute(Dwarf::Attribute::Ranges).has_value()) {
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dbgln_if(SPAM_DEBUG, "DWARF ranges are not supported");
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return;
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}
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auto name = child.get_attribute(Dwarf::Attribute::Name);
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VariablesScope scope {};
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scope.is_function = (child.tag() == Dwarf::EntryTag::SubProgram);
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if (name.has_value())
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scope.name = name.value().as_string();
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if (!child.get_attribute(Dwarf::Attribute::LowPc).has_value()) {
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dbgln_if(SPAM_DEBUG, "DWARF: Couldn't find attribute LowPc for scope");
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return;
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}
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scope.address_low = child.get_attribute(Dwarf::Attribute::LowPc).value().as_addr();
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auto high_pc = child.get_attribute(Dwarf::Attribute::HighPc);
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if (high_pc->type() == Dwarf::AttributeValue::Type::Address)
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scope.address_high = high_pc->as_addr();
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else
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scope.address_high = scope.address_low + high_pc->as_unsigned();
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child.for_each_child([&](Dwarf::DIE const& variable_entry) {
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if (!(variable_entry.tag() == Dwarf::EntryTag::Variable
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|| variable_entry.tag() == Dwarf::EntryTag::FormalParameter))
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return;
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scope.dies_of_variables.append(variable_entry);
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});
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m_scopes.append(scope);
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parse_scopes_impl(child);
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});
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}
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void DebugInfo::prepare_lines()
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{
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Vector<Dwarf::LineProgram::LineInfo> all_lines;
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m_dwarf_info.for_each_compilation_unit([&all_lines](Dwarf::CompilationUnit const& unit) {
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all_lines.extend(unit.line_program().lines());
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});
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HashMap<FlyString, Optional<String>> memoized_full_paths;
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auto compute_full_path = [&](FlyString const& file_path) -> Optional<String> {
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if (file_path.view().contains("Toolchain/"sv) || file_path.view().contains("libgcc"sv))
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return {};
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if (file_path.view().starts_with("./"sv) && !m_source_root.is_null())
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return LexicalPath::join(m_source_root, file_path).string();
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if (auto index_of_serenity_slash = file_path.view().find("serenity/"sv); index_of_serenity_slash.has_value()) {
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auto start_index = index_of_serenity_slash.value() + "serenity/"sv.length();
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return file_path.view().substring_view(start_index, file_path.length() - start_index);
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}
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return file_path;
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};
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m_sorted_lines.ensure_capacity(all_lines.size());
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for (auto const& line_info : all_lines) {
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auto maybe_full_path = memoized_full_paths.ensure(line_info.file, [&] { return compute_full_path(line_info.file); });
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if (!maybe_full_path.has_value())
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continue;
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m_sorted_lines.unchecked_append({ line_info.address, maybe_full_path.release_value(), line_info.line });
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}
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quick_sort(m_sorted_lines, [](auto& a, auto& b) {
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return a.address < b.address;
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});
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}
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Optional<DebugInfo::SourcePosition> DebugInfo::get_source_position(FlatPtr target_address) const
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{
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if (m_sorted_lines.is_empty())
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return {};
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if (target_address < m_sorted_lines[0].address)
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return {};
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// TODO: We can do a binary search here
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for (size_t i = 0; i < m_sorted_lines.size() - 1; ++i) {
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if (m_sorted_lines[i + 1].address > target_address) {
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return SourcePosition::from_line_info(m_sorted_lines[i]);
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}
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}
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return {};
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}
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Optional<DebugInfo::SourcePositionAndAddress> DebugInfo::get_address_from_source_position(String const& file, size_t line) const
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{
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String file_path = file;
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if (!file_path.starts_with("/"))
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file_path = String::formatted("/{}", file_path);
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constexpr char SERENITY_LIBS_PREFIX[] = "/usr/src/serenity";
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if (file.starts_with(SERENITY_LIBS_PREFIX)) {
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file_path = file.substring(sizeof(SERENITY_LIBS_PREFIX), file.length() - sizeof(SERENITY_LIBS_PREFIX));
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file_path = String::formatted("../{}", file_path);
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}
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Optional<SourcePositionAndAddress> result;
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for (const auto& line_entry : m_sorted_lines) {
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if (!line_entry.file.ends_with(file_path))
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continue;
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if (line_entry.line > line)
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continue;
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// We look for the source position that is closest to the desired position, and is not after it.
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// For example, get_address_of_source_position("main.cpp", 73) could return the address for an instruction whose location is ("main.cpp", 72)
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// as there might not be an instruction mapped for "main.cpp", 73.
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if (!result.has_value() || (line_entry.line > result.value().line)) {
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result = SourcePositionAndAddress { line_entry.file, line_entry.line, line_entry.address };
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}
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}
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return result;
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}
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NonnullOwnPtrVector<DebugInfo::VariableInfo> DebugInfo::get_variables_in_current_scope(const PtraceRegisters& regs) const
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{
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NonnullOwnPtrVector<DebugInfo::VariableInfo> variables;
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// TODO: We can store the scopes in a better data structure
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for (const auto& scope : m_scopes) {
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FlatPtr ip;
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#if ARCH(I386)
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ip = regs.eip;
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#else
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ip = regs.rip;
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#endif
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if (ip - m_base_address < scope.address_low || ip - m_base_address >= scope.address_high)
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continue;
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for (const auto& die_entry : scope.dies_of_variables) {
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auto variable_info = create_variable_info(die_entry, regs);
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if (!variable_info)
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continue;
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variables.append(variable_info.release_nonnull());
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}
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}
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return variables;
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}
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static Optional<Dwarf::DIE> parse_variable_type_die(Dwarf::DIE const& variable_die, DebugInfo::VariableInfo& variable_info)
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{
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auto type_die_offset = variable_die.get_attribute(Dwarf::Attribute::Type);
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if (!type_die_offset.has_value())
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return {};
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VERIFY(type_die_offset.value().type() == Dwarf::AttributeValue::Type::DieReference);
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auto type_die = variable_die.compilation_unit().get_die_at_offset(type_die_offset.value().as_unsigned());
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auto type_name = type_die.get_attribute(Dwarf::Attribute::Name);
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if (type_name.has_value()) {
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variable_info.type_name = type_name.value().as_string();
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} else {
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dbgln("Unnamed DWARF type at offset: {}", type_die.offset());
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variable_info.type_name = "[Unnamed Type]";
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}
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return type_die;
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}
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static void parse_variable_location(Dwarf::DIE const& variable_die, DebugInfo::VariableInfo& variable_info, PtraceRegisters const& regs)
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{
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auto location_info = variable_die.get_attribute(Dwarf::Attribute::Location);
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if (!location_info.has_value()) {
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location_info = variable_die.get_attribute(Dwarf::Attribute::MemberLocation);
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}
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if (!location_info.has_value())
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return;
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switch (location_info.value().type()) {
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case Dwarf::AttributeValue::Type::UnsignedNumber:
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variable_info.location_type = DebugInfo::VariableInfo::LocationType::Address;
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variable_info.location_data.address = location_info.value().as_unsigned();
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break;
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case Dwarf::AttributeValue::Type::DwarfExpression: {
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auto expression_bytes = location_info.value().as_raw_bytes();
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auto value = Dwarf::Expression::evaluate(expression_bytes, regs);
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if (value.type != Dwarf::Expression::Type::None) {
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VERIFY(value.type == Dwarf::Expression::Type::UnsignedInteger);
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variable_info.location_type = DebugInfo::VariableInfo::LocationType::Address;
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variable_info.location_data.address = value.data.as_addr;
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}
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break;
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}
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default:
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dbgln("Warning: unhandled Dwarf location type: {}", (int)location_info.value().type());
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}
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}
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OwnPtr<DebugInfo::VariableInfo> DebugInfo::create_variable_info(Dwarf::DIE const& variable_die, PtraceRegisters const& regs, u32 address_offset) const
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{
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VERIFY(is_variable_tag_supported(variable_die.tag()));
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if (variable_die.tag() == Dwarf::EntryTag::FormalParameter
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&& !variable_die.get_attribute(Dwarf::Attribute::Name).has_value()) {
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// We don't want to display info for unused parameters
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return {};
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}
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NonnullOwnPtr<VariableInfo> variable_info = make<VariableInfo>();
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auto name_attribute = variable_die.get_attribute(Dwarf::Attribute::Name);
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if (name_attribute.has_value())
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variable_info->name = name_attribute.value().as_string();
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auto type_die = parse_variable_type_die(variable_die, *variable_info);
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if (variable_die.tag() == Dwarf::EntryTag::Enumerator) {
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auto constant = variable_die.get_attribute(Dwarf::Attribute::ConstValue);
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VERIFY(constant.has_value());
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switch (constant.value().type()) {
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case Dwarf::AttributeValue::Type::UnsignedNumber:
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variable_info->constant_data.as_u32 = constant.value().as_unsigned();
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break;
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case Dwarf::AttributeValue::Type::SignedNumber:
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variable_info->constant_data.as_i32 = constant.value().as_signed();
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break;
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case Dwarf::AttributeValue::Type::String:
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variable_info->constant_data.as_string = constant.value().as_string();
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break;
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default:
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VERIFY_NOT_REACHED();
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}
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} else {
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parse_variable_location(variable_die, *variable_info, regs);
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variable_info->location_data.address += address_offset;
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}
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if (type_die.has_value())
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add_type_info_to_variable(type_die.value(), regs, variable_info);
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return variable_info;
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}
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void DebugInfo::add_type_info_to_variable(Dwarf::DIE const& type_die, PtraceRegisters const& regs, DebugInfo::VariableInfo* parent_variable) const
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{
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OwnPtr<VariableInfo> type_info;
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auto is_array_type = type_die.tag() == Dwarf::EntryTag::ArrayType;
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if (type_die.tag() == Dwarf::EntryTag::EnumerationType
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|| type_die.tag() == Dwarf::EntryTag::StructureType
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|| is_array_type) {
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type_info = create_variable_info(type_die, regs);
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}
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type_die.for_each_child([&](Dwarf::DIE const& member) {
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if (member.is_null())
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return;
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if (is_array_type && member.tag() == Dwarf::EntryTag::SubRangeType) {
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auto upper_bound = member.get_attribute(Dwarf::Attribute::UpperBound);
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VERIFY(upper_bound.has_value());
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auto size = upper_bound.value().as_unsigned() + 1;
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type_info->dimension_sizes.append(size);
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return;
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}
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if (!is_variable_tag_supported(member.tag()))
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return;
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auto member_variable = create_variable_info(member, regs, parent_variable->location_data.address);
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VERIFY(member_variable);
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if (type_die.tag() == Dwarf::EntryTag::EnumerationType) {
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member_variable->parent = type_info.ptr();
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type_info->members.append(member_variable.release_nonnull());
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} else {
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if (parent_variable->location_type != DebugInfo::VariableInfo::LocationType::Address)
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return;
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member_variable->parent = parent_variable;
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parent_variable->members.append(member_variable.release_nonnull());
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}
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});
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if (type_info) {
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if (is_array_type) {
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StringBuilder array_type_name;
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array_type_name.append(type_info->type_name);
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for (auto array_size : type_info->dimension_sizes) {
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array_type_name.append("[");
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array_type_name.append(String::formatted("{:d}", array_size));
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array_type_name.append("]");
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}
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parent_variable->type_name = array_type_name.to_string();
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}
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parent_variable->type = move(type_info);
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parent_variable->type->type_tag = type_die.tag();
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}
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}
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bool DebugInfo::is_variable_tag_supported(Dwarf::EntryTag const& tag)
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{
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return tag == Dwarf::EntryTag::Variable
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|| tag == Dwarf::EntryTag::Member
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|| tag == Dwarf::EntryTag::FormalParameter
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|| tag == Dwarf::EntryTag::EnumerationType
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|| tag == Dwarf::EntryTag::Enumerator
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|| tag == Dwarf::EntryTag::StructureType
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|| tag == Dwarf::EntryTag::ArrayType;
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}
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String DebugInfo::name_of_containing_function(FlatPtr address) const
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{
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auto function = get_containing_function(address);
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if (!function.has_value())
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return {};
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return function.value().name;
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}
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Optional<DebugInfo::VariablesScope> DebugInfo::get_containing_function(FlatPtr address) const
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{
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for (const auto& scope : m_scopes) {
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if (!scope.is_function || address < scope.address_low || address >= scope.address_high)
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continue;
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return scope;
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}
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return {};
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}
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Vector<DebugInfo::SourcePosition> DebugInfo::source_lines_in_scope(VariablesScope const& scope) const
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{
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Vector<DebugInfo::SourcePosition> source_lines;
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for (const auto& line : m_sorted_lines) {
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if (line.address < scope.address_low)
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continue;
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if (line.address >= scope.address_high)
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break;
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source_lines.append(SourcePosition::from_line_info(line));
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}
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return source_lines;
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}
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DebugInfo::SourcePosition DebugInfo::SourcePosition::from_line_info(Dwarf::LineProgram::LineInfo const& line)
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{
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return { line.file, line.line, line.address };
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}
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DebugInfo::SourcePositionWithInlines DebugInfo::get_source_position_with_inlines(FlatPtr address) const
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{
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// If the address is in an "inline chain", this is the inner-most inlined position.
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auto inner_source_position = get_source_position(address);
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auto die = m_dwarf_info.get_die_at_address(address);
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if (!die.has_value() || die->tag() == Dwarf::EntryTag::SubroutineType) {
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// Inline chain is empty
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return SourcePositionWithInlines { inner_source_position, {} };
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}
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Vector<SourcePosition> inline_chain;
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auto insert_to_chain = [&](Dwarf::DIE const& die) {
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auto caller_source_path = get_source_path_of_inline(die);
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auto caller_line = get_line_of_inline(die);
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if (!caller_source_path.has_value() || !caller_line.has_value()) {
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return;
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}
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inline_chain.append({ String::formatted("{}/{}", caller_source_path->directory, caller_source_path->filename), caller_line.value() });
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};
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while (die->tag() == Dwarf::EntryTag::InlinedSubroutine) {
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insert_to_chain(*die);
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if (!die->parent_offset().has_value()) {
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break;
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}
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auto parent = die->compilation_unit().dwarf_info().get_cached_die_at_offset(die->parent_offset().value());
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if (!parent.has_value()) {
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break;
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}
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die = *parent;
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}
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return SourcePositionWithInlines { inner_source_position, inline_chain };
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}
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Optional<Dwarf::LineProgram::DirectoryAndFile> DebugInfo::get_source_path_of_inline(Dwarf::DIE const& die) const
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{
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auto caller_file = die.get_attribute(Dwarf::Attribute::CallFile);
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if (caller_file.has_value()) {
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u32 file_index = 0;
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if (caller_file->type() == Dwarf::AttributeValue::Type::UnsignedNumber) {
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file_index = caller_file->as_unsigned();
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} else if (caller_file->type() == Dwarf::AttributeValue::Type::SignedNumber) {
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// For some reason, the file_index is sometimes stored as a signed number.
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VERIFY(caller_file->as_signed() >= 0);
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file_index = (u32)caller_file->as_signed();
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} else {
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return {};
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}
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return die.compilation_unit().line_program().get_directory_and_file(file_index);
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}
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return {};
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}
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Optional<uint32_t> DebugInfo::get_line_of_inline(Dwarf::DIE const& die) const
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{
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auto caller_line = die.get_attribute(Dwarf::Attribute::CallLine);
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if (!caller_line.has_value())
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return {};
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if (caller_line->type() != Dwarf::AttributeValue::Type::UnsignedNumber)
|
|
return {};
|
|
return caller_line.value().as_unsigned();
|
|
}
|
|
|
|
}
|