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LibDebug: Implement support for AttributeDataForm::ImplicitConst

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While symbolicating a crash dump for UserspaceEmulator I came across
another data form we didn't support.

ImplicitConst encodes a LEB128 value in the abbreviation record
rather than - like all other values - in the .debug_info section.
This commit is contained in:
Gunnar Beutner 2021-04-29 00:51:54 +02:00 • committed by Andreas Kling
parent 278605cde6
commit 9bcdbe205b
6 changed files with 18 additions and 5 deletions
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6
Userland/Libraries/LibDebug/Dwarf/AbbreviationsMap.cpp
View file

@ -51,6 +51,12 @@ void AbbreviationsMap::populate_map()
current_attribute_specification.attribute = static_cast<Attribute>(attribute_value);
current_attribute_specification.form = static_cast<AttributeDataForm>(form_value);
if (current_attribute_specification.form == AttributeDataForm::ImplicitConst) {
ssize_t data_value;
abbreviation_stream.read_LEB128_signed(data_value);
current_attribute_specification.value = data_value;
}
if (current_attribute_specification.attribute != Attribute::None) {
abbrevation_entry.attribute_specifications.append(current_attribute_specification);
}

4
Userland/Libraries/LibDebug/Dwarf/DIE.cpp
View file

@ -33,7 +33,7 @@ DIE::DIE(const CompilationUnit& unit, u32 offset)
// We iterate the attributes data only to calculate this DIE's size
for (auto& attribute_spec : abbreviation_info.value().attribute_specifications) {
m_compilation_unit.dwarf_info().get_attribute_value(attribute_spec.form, stream, &m_compilation_unit);
m_compilation_unit.dwarf_info().get_attribute_value(attribute_spec.form, attribute_spec.value, stream, &m_compilation_unit);
}
}
m_size = stream.offset() - m_offset;
@ -48,7 +48,7 @@ Optional<AttributeValue> DIE::get_attribute(const Attribute& attribute) const
VERIFY(abbreviation_info.has_value());
for (const auto& attribute_spec : abbreviation_info.value().attribute_specifications) {
auto value = m_compilation_unit.dwarf_info().get_attribute_value(attribute_spec.form, stream, &m_compilation_unit);
auto value = m_compilation_unit.dwarf_info().get_attribute_value(attribute_spec.form, attribute_spec.value, stream, &m_compilation_unit);
if (attribute_spec.attribute == attribute) {
return value;
}

8
Userland/Libraries/LibDebug/Dwarf/DwarfInfo.cpp
View file

@ -49,7 +49,7 @@ void DwarfInfo::populate_compilation_units()
}
}
AttributeValue DwarfInfo::get_attribute_value(AttributeDataForm form,
AttributeValue DwarfInfo::get_attribute_value(AttributeDataForm form, ssize_t implicit_const_value,
InputMemoryStream& debug_info_stream, const CompilationUnit* unit) const
{
AttributeValue value;
@ -210,6 +210,12 @@ AttributeValue DwarfInfo::get_attribute_value(AttributeDataForm form,
value.data.as_string = reinterpret_cast<const char*>(strings_data.data() + offset);
break;
}
case AttributeDataForm::ImplicitConst: {
/* Value is part of the abbreviation record. */
value.type = AttributeValue::Type::SignedNumber;
value.data.as_i32 = implicit_const_value;
break;
}
default:
dbgln("Unimplemented AttributeDataForm: {}", (u32)form);
VERIFY_NOT_REACHED();

2
Userland/Libraries/LibDebug/Dwarf/DwarfInfo.h
View file

@ -54,7 +54,7 @@ public:
template<typename Callback>
void for_each_compilation_unit(Callback) const;
AttributeValue get_attribute_value(AttributeDataForm form,
AttributeValue get_attribute_value(AttributeDataForm form, ssize_t implicit_const_value,
InputMemoryStream& debug_info_stream, const CompilationUnit* unit = nullptr) const;
private:

1
Userland/Libraries/LibDebug/Dwarf/DwarfTypes.h
View file

@ -314,6 +314,7 @@ enum class AttributeDataForm : u8 {
struct [[gnu::packed]] AttributeSpecification {
Attribute attribute;
AttributeDataForm form;
ssize_t value;
};
}

2
Userland/Libraries/LibDebug/Dwarf/LineProgram.cpp
View file

@ -57,7 +57,7 @@ void LineProgram::parse_path_entries(Function<void(PathEntry& entry)> callback,
for (size_t i = 0; i < paths_count; i++) {
PathEntry entry;
for (auto& format_description : format_descriptions) {
auto value = m_dwarf_info.get_attribute_value(format_description.form, m_stream);
auto value = m_dwarf_info.get_attribute_value(format_description.form, 0, m_stream);
switch (format_description.type) {
case ContentType::Path:
entry.path = value.data.as_string;