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- /*
- * Copyright (c) 2020-2021, Itamar S. <itamar8910@gmail.com>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
- #include "DebugInfo.h"
- #include <AK/Debug.h>
- #include <AK/LexicalPath.h>
- #include <AK/MemoryStream.h>
- #include <AK/QuickSort.h>
- #include <LibDebug/Dwarf/CompilationUnit.h>
- #include <LibDebug/Dwarf/DwarfInfo.h>
- #include <LibDebug/Dwarf/Expression.h>
- namespace Debug {
- DebugInfo::DebugInfo(ELF::Image const& elf, String source_root, FlatPtr base_address)
- : m_elf(elf)
- , m_source_root(move(source_root))
- , m_base_address(base_address)
- , m_dwarf_info(m_elf)
- {
- prepare_variable_scopes();
- prepare_lines();
- }
- void DebugInfo::prepare_variable_scopes()
- {
- m_dwarf_info.for_each_compilation_unit([&](Dwarf::CompilationUnit const& unit) {
- auto root = unit.root_die();
- parse_scopes_impl(root);
- });
- }
- void DebugInfo::parse_scopes_impl(Dwarf::DIE const& die)
- {
- die.for_each_child([&](Dwarf::DIE const& child) {
- if (child.is_null())
- return;
- if (!(child.tag() == Dwarf::EntryTag::SubProgram || child.tag() == Dwarf::EntryTag::LexicalBlock))
- return;
- if (child.get_attribute(Dwarf::Attribute::Inline).has_value()) {
- dbgln_if(SPAM_DEBUG, "DWARF inlined functions are not supported");
- return;
- }
- if (child.get_attribute(Dwarf::Attribute::Ranges).has_value()) {
- dbgln_if(SPAM_DEBUG, "DWARF ranges are not supported");
- return;
- }
- auto name = child.get_attribute(Dwarf::Attribute::Name);
- VariablesScope scope {};
- scope.is_function = (child.tag() == Dwarf::EntryTag::SubProgram);
- if (name.has_value())
- scope.name = name.value().data.as_string;
- if (!child.get_attribute(Dwarf::Attribute::LowPc).has_value()) {
- dbgln_if(SPAM_DEBUG, "DWARF: Couldn't find attribute LowPc for scope");
- return;
- }
- scope.address_low = child.get_attribute(Dwarf::Attribute::LowPc).value().data.as_addr;
- // The attribute name HighPc is confusing. In this context, it seems to actually be a positive offset from LowPc
- scope.address_high = scope.address_low + child.get_attribute(Dwarf::Attribute::HighPc).value().data.as_addr;
- child.for_each_child([&](Dwarf::DIE const& variable_entry) {
- if (!(variable_entry.tag() == Dwarf::EntryTag::Variable
- || variable_entry.tag() == Dwarf::EntryTag::FormalParameter))
- return;
- scope.dies_of_variables.append(variable_entry);
- });
- m_scopes.append(scope);
- parse_scopes_impl(child);
- });
- }
- void DebugInfo::prepare_lines()
- {
- Vector<Dwarf::LineProgram::LineInfo> all_lines;
- m_dwarf_info.for_each_compilation_unit([&all_lines](Dwarf::CompilationUnit const& unit) {
- all_lines.extend(unit.line_program().lines());
- });
- HashMap<FlyString, Optional<String>> memoized_full_paths;
- auto compute_full_path = [&](FlyString const& file_path) -> Optional<String> {
- if (file_path.view().contains("Toolchain/"sv) || file_path.view().contains("libgcc"sv))
- return {};
- if (file_path.view().starts_with("./"sv) && !m_source_root.is_null())
- return LexicalPath::join(m_source_root, file_path).string();
- if (auto index_of_serenity_slash = file_path.view().find("serenity/"sv); index_of_serenity_slash.has_value()) {
- auto start_index = index_of_serenity_slash.value() + "serenity/"sv.length();
- return file_path.view().substring_view(start_index, file_path.length() - start_index);
- }
- return file_path;
- };
- m_sorted_lines.ensure_capacity(all_lines.size());
- for (auto const& line_info : all_lines) {
- auto it = memoized_full_paths.find(line_info.file);
- if (it == memoized_full_paths.end()) {
- memoized_full_paths.set(line_info.file, compute_full_path(line_info.file));
- it = memoized_full_paths.find(line_info.file);
- }
- if (!it->value.has_value())
- continue;
- m_sorted_lines.unchecked_append({ line_info.address, it->value.value(), line_info.line });
- }
- quick_sort(m_sorted_lines, [](auto& a, auto& b) {
- return a.address < b.address;
- });
- }
- Optional<DebugInfo::SourcePosition> DebugInfo::get_source_position(FlatPtr target_address) const
- {
- if (m_sorted_lines.is_empty())
- return {};
- if (target_address < m_sorted_lines[0].address)
- return {};
- // TODO: We can do a binary search here
- for (size_t i = 0; i < m_sorted_lines.size() - 1; ++i) {
- if (m_sorted_lines[i + 1].address > target_address) {
- return SourcePosition::from_line_info(m_sorted_lines[i]);
- }
- }
- return {};
- }
- Optional<DebugInfo::SourcePositionAndAddress> DebugInfo::get_address_from_source_position(String const& file, size_t line) const
- {
- String file_path = file;
- if (!file_path.starts_with("/"))
- file_path = String::formatted("/{}", file_path);
- constexpr char SERENITY_LIBS_PREFIX[] = "/usr/src/serenity";
- if (file.starts_with(SERENITY_LIBS_PREFIX)) {
- file_path = file.substring(sizeof(SERENITY_LIBS_PREFIX), file.length() - sizeof(SERENITY_LIBS_PREFIX));
- file_path = String::formatted("../{}", file_path);
- }
- Optional<SourcePositionAndAddress> result;
- for (const auto& line_entry : m_sorted_lines) {
- if (!line_entry.file.ends_with(file_path))
- continue;
- if (line_entry.line > line)
- continue;
- // We look for the source position that is closest to the desired position, and is not after it.
- // For example, get_address_of_source_position("main.cpp", 73) could return the address for an instruction whose location is ("main.cpp", 72)
- // as there might not be an instruction mapped for "main.cpp", 73.
- if (!result.has_value() || (line_entry.line > result.value().line)) {
- result = SourcePositionAndAddress { line_entry.file, line_entry.line, line_entry.address };
- }
- }
- return result;
- }
- NonnullOwnPtrVector<DebugInfo::VariableInfo> DebugInfo::get_variables_in_current_scope(const PtraceRegisters& regs) const
- {
- NonnullOwnPtrVector<DebugInfo::VariableInfo> variables;
- // TODO: We can store the scopes in a better data structure
- for (const auto& scope : m_scopes) {
- FlatPtr ip;
- #if ARCH(I386)
- ip = regs.eip;
- #else
- ip = regs.rip;
- #endif
- if (ip - m_base_address < scope.address_low || ip - m_base_address >= scope.address_high)
- continue;
- for (const auto& die_entry : scope.dies_of_variables) {
- auto variable_info = create_variable_info(die_entry, regs);
- if (!variable_info)
- continue;
- variables.append(variable_info.release_nonnull());
- }
- }
- return variables;
- }
- static Optional<Dwarf::DIE> parse_variable_type_die(Dwarf::DIE const& variable_die, DebugInfo::VariableInfo& variable_info)
- {
- auto type_die_offset = variable_die.get_attribute(Dwarf::Attribute::Type);
- if (!type_die_offset.has_value())
- return {};
- VERIFY(type_die_offset.value().type == Dwarf::AttributeValue::Type::DieReference);
- auto type_die = variable_die.compilation_unit().get_die_at_offset(type_die_offset.value().data.as_u32);
- auto type_name = type_die.get_attribute(Dwarf::Attribute::Name);
- if (type_name.has_value()) {
- variable_info.type_name = type_name.value().data.as_string;
- } else {
- dbgln("Unnamed DWARF type at offset: {}", type_die.offset());
- variable_info.type_name = "[Unnamed Type]";
- }
- return type_die;
- }
- static void parse_variable_location(Dwarf::DIE const& variable_die, DebugInfo::VariableInfo& variable_info, PtraceRegisters const& regs)
- {
- auto location_info = variable_die.get_attribute(Dwarf::Attribute::Location);
- if (!location_info.has_value()) {
- location_info = variable_die.get_attribute(Dwarf::Attribute::MemberLocation);
- }
- if (!location_info.has_value())
- return;
- switch (location_info.value().type) {
- case Dwarf::AttributeValue::Type::UnsignedNumber:
- variable_info.location_type = DebugInfo::VariableInfo::LocationType::Address;
- variable_info.location_data.address = location_info.value().data.as_addr;
- break;
- case Dwarf::AttributeValue::Type::DwarfExpression: {
- auto expression_bytes = ReadonlyBytes { location_info.value().data.as_raw_bytes.bytes, location_info.value().data.as_raw_bytes.length };
- auto value = Dwarf::Expression::evaluate(expression_bytes, regs);
- if (value.type != Dwarf::Expression::Type::None) {
- VERIFY(value.type == Dwarf::Expression::Type::UnsignedInteger);
- variable_info.location_type = DebugInfo::VariableInfo::LocationType::Address;
- variable_info.location_data.address = value.data.as_addr;
- }
- break;
- }
- default:
- dbgln("Warning: unhandled Dwarf location type: {}", (int)location_info.value().type);
- }
- }
- OwnPtr<DebugInfo::VariableInfo> DebugInfo::create_variable_info(Dwarf::DIE const& variable_die, PtraceRegisters const& regs, u32 address_offset) const
- {
- VERIFY(is_variable_tag_supported(variable_die.tag()));
- if (variable_die.tag() == Dwarf::EntryTag::FormalParameter
- && !variable_die.get_attribute(Dwarf::Attribute::Name).has_value()) {
- // We don't want to display info for unused parameters
- return {};
- }
- NonnullOwnPtr<VariableInfo> variable_info = make<VariableInfo>();
- auto name_attribute = variable_die.get_attribute(Dwarf::Attribute::Name);
- if (name_attribute.has_value())
- variable_info->name = name_attribute.value().data.as_string;
- auto type_die = parse_variable_type_die(variable_die, *variable_info);
- if (variable_die.tag() == Dwarf::EntryTag::Enumerator) {
- auto constant = variable_die.get_attribute(Dwarf::Attribute::ConstValue);
- VERIFY(constant.has_value());
- switch (constant.value().type) {
- case Dwarf::AttributeValue::Type::UnsignedNumber:
- variable_info->constant_data.as_u32 = constant.value().data.as_u32;
- break;
- case Dwarf::AttributeValue::Type::SignedNumber:
- variable_info->constant_data.as_i32 = constant.value().data.as_i32;
- break;
- case Dwarf::AttributeValue::Type::String:
- variable_info->constant_data.as_string = constant.value().data.as_string;
- break;
- default:
- VERIFY_NOT_REACHED();
- }
- } else {
- parse_variable_location(variable_die, *variable_info, regs);
- variable_info->location_data.address += address_offset;
- }
- if (type_die.has_value())
- add_type_info_to_variable(type_die.value(), regs, variable_info);
- return variable_info;
- }
- void DebugInfo::add_type_info_to_variable(Dwarf::DIE const& type_die, PtraceRegisters const& regs, DebugInfo::VariableInfo* parent_variable) const
- {
- OwnPtr<VariableInfo> type_info;
- auto is_array_type = type_die.tag() == Dwarf::EntryTag::ArrayType;
- if (type_die.tag() == Dwarf::EntryTag::EnumerationType
- || type_die.tag() == Dwarf::EntryTag::StructureType
- || is_array_type) {
- type_info = create_variable_info(type_die, regs);
- }
- type_die.for_each_child([&](Dwarf::DIE const& member) {
- if (member.is_null())
- return;
- if (is_array_type && member.tag() == Dwarf::EntryTag::SubRangeType) {
- auto upper_bound = member.get_attribute(Dwarf::Attribute::UpperBound);
- VERIFY(upper_bound.has_value());
- auto size = upper_bound.value().data.as_u32 + 1;
- type_info->dimension_sizes.append(size);
- return;
- }
- if (!is_variable_tag_supported(member.tag()))
- return;
- auto member_variable = create_variable_info(member, regs, parent_variable->location_data.address);
- VERIFY(member_variable);
- if (type_die.tag() == Dwarf::EntryTag::EnumerationType) {
- member_variable->parent = type_info.ptr();
- type_info->members.append(member_variable.release_nonnull());
- } else {
- if (parent_variable->location_type != DebugInfo::VariableInfo::LocationType::Address)
- return;
- member_variable->parent = parent_variable;
- parent_variable->members.append(member_variable.release_nonnull());
- }
- });
- if (type_info) {
- if (is_array_type) {
- StringBuilder array_type_name;
- array_type_name.append(type_info->type_name);
- for (auto array_size : type_info->dimension_sizes) {
- array_type_name.append("[");
- array_type_name.append(String::formatted("{:d}", array_size));
- array_type_name.append("]");
- }
- parent_variable->type_name = array_type_name.to_string();
- }
- parent_variable->type = move(type_info);
- parent_variable->type->type_tag = type_die.tag();
- }
- }
- bool DebugInfo::is_variable_tag_supported(Dwarf::EntryTag const& tag)
- {
- return tag == Dwarf::EntryTag::Variable
- || tag == Dwarf::EntryTag::Member
- || tag == Dwarf::EntryTag::FormalParameter
- || tag == Dwarf::EntryTag::EnumerationType
- || tag == Dwarf::EntryTag::Enumerator
- || tag == Dwarf::EntryTag::StructureType
- || tag == Dwarf::EntryTag::ArrayType;
- }
- String DebugInfo::name_of_containing_function(FlatPtr address) const
- {
- auto function = get_containing_function(address);
- if (!function.has_value())
- return {};
- return function.value().name;
- }
- Optional<DebugInfo::VariablesScope> DebugInfo::get_containing_function(FlatPtr address) const
- {
- for (const auto& scope : m_scopes) {
- if (!scope.is_function || address < scope.address_low || address >= scope.address_high)
- continue;
- return scope;
- }
- return {};
- }
- Vector<DebugInfo::SourcePosition> DebugInfo::source_lines_in_scope(VariablesScope const& scope) const
- {
- Vector<DebugInfo::SourcePosition> source_lines;
- for (const auto& line : m_sorted_lines) {
- if (line.address < scope.address_low)
- continue;
- if (line.address >= scope.address_high)
- break;
- source_lines.append(SourcePosition::from_line_info(line));
- }
- return source_lines;
- }
- DebugInfo::SourcePosition DebugInfo::SourcePosition::from_line_info(Dwarf::LineProgram::LineInfo const& line)
- {
- return { line.file, line.line, line.address };
- }
- DebugInfo::SourcePositionWithInlines DebugInfo::get_source_position_with_inlines(FlatPtr address) const
- {
- // If the address is in an "inline chain", this is the inner-most inlined position.
- auto inner_source_position = get_source_position(address);
- auto die = m_dwarf_info.get_die_at_address(address);
- if (!die.has_value() || die->tag() == Dwarf::EntryTag::SubroutineType) {
- // Inline chain is empty
- return SourcePositionWithInlines { inner_source_position, {} };
- }
- Vector<SourcePosition> inline_chain;
- auto insert_to_chain = [&](Dwarf::DIE const& die) {
- auto caller_source_path = get_source_path_of_inline(die);
- auto caller_line = get_line_of_inline(die);
- if (!caller_source_path.has_value() || !caller_line.has_value()) {
- return;
- }
- inline_chain.append({ String::formatted("{}/{}", caller_source_path->directory, caller_source_path->filename), caller_line.value() });
- };
- while (die->tag() == Dwarf::EntryTag::InlinedSubroutine) {
- insert_to_chain(*die);
- if (!die->parent_offset().has_value()) {
- break;
- }
- auto parent = die->compilation_unit().dwarf_info().get_cached_die_at_offset(die->parent_offset().value());
- if (!parent.has_value()) {
- break;
- }
- die = *parent;
- }
- return SourcePositionWithInlines { inner_source_position, inline_chain };
- }
- Optional<Dwarf::LineProgram::DirectoryAndFile> DebugInfo::get_source_path_of_inline(Dwarf::DIE const& die) const
- {
- auto caller_file = die.get_attribute(Dwarf::Attribute::CallFile);
- if (caller_file.has_value()) {
- u32 file_index = 0;
- if (caller_file->type == Dwarf::AttributeValue::Type::UnsignedNumber) {
- file_index = caller_file->data.as_u32;
- } else if (caller_file->type == Dwarf::AttributeValue::Type::SignedNumber) {
- // For some reason, the file_index is sometimes stored as a signed number.
- VERIFY(caller_file->data.as_i32 >= 0);
- file_index = (u32)caller_file->data.as_i32;
- } else {
- return {};
- }
- return die.compilation_unit().line_program().get_directory_and_file(file_index);
- }
- return {};
- }
- Optional<uint32_t> DebugInfo::get_line_of_inline(Dwarf::DIE const& die) const
- {
- auto caller_line = die.get_attribute(Dwarf::Attribute::CallLine);
- if (!caller_line.has_value())
- return {};
- if (caller_line->type != Dwarf::AttributeValue::Type::UnsignedNumber)
- return {};
- return caller_line.value().data.as_u32;
- }
- }
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