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LibDebug: Store 64-bit numbers in AttributeValue

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This helps us avoid weird truncation issues and fixes a bug on Clang
builds where truncation while reading caused the DIE offsets following
large LEB128 numbers to be incorrect. This removes the need for the
separate `LongUnsignedNumber` type.
This commit is contained in:
Daniel Bertalan 2021-07-27 11:03:24 +02:00 • committed by Andreas Kling
parent efd1aea969
commit 7396e4aedc
6 changed files with 32 additions and 31 deletions
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6
Userland/Libraries/LibDebug/Dwarf/AttributeValue.h
View file

@ -15,7 +15,6 @@ struct AttributeValue {
enum class Type : u8 {
UnsignedNumber,
SignedNumber,
LongUnsignedNumber,
String,
DieReference, // Reference to another DIE in the same compilation unit
Boolean,
@ -26,9 +25,8 @@ struct AttributeValue {
union {
FlatPtr as_addr;
u32 as_u32;
i32 as_i32;
u64 as_u64;
u64 as_unsigned;
i64 as_signed;
const char* as_string; // points to bytes in the memory mapped elf image
bool as_bool;
struct {

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

@ -75,7 +75,7 @@ void DIE::for_each_child(Function<void(DIE const& child)> callback) const
auto sibling = current_child->get_attribute(Attribute::Sibling);
u32 sibling_offset = 0;
if (sibling.has_value()) {
sibling_offset = sibling.value().data.as_u32;
sibling_offset = sibling.value().data.as_unsigned;
}
if (!sibling.has_value()) {

30
Userland/Libraries/LibDebug/Dwarf/DwarfInfo.cpp
View file

@ -90,7 +90,7 @@ AttributeValue DwarfInfo::get_attribute_value(AttributeDataForm form, ssize_t im
debug_info_stream >> data;
VERIFY(!debug_info_stream.has_any_error());
value.type = AttributeValue::Type::UnsignedNumber;
value.data.as_u32 = data;
value.data.as_unsigned = data;
break;
}
case AttributeDataForm::Data2: {
@ -98,7 +98,7 @@ AttributeValue DwarfInfo::get_attribute_value(AttributeDataForm form, ssize_t im
debug_info_stream >> data;
VERIFY(!debug_info_stream.has_any_error());
value.type = AttributeValue::Type::UnsignedNumber;
value.data.as_u32 = data;
value.data.as_signed = data;
break;
}
case AttributeDataForm::Addr: {
@ -110,19 +110,19 @@ AttributeValue DwarfInfo::get_attribute_value(AttributeDataForm form, ssize_t im
break;
}
case AttributeDataForm::SData: {
ssize_t data;
i64 data;
debug_info_stream.read_LEB128_signed(data);
VERIFY(!debug_info_stream.has_any_error());
value.type = AttributeValue::Type::SignedNumber;
value.data.as_i32 = data;
value.data.as_signed = data;
break;
}
case AttributeDataForm::UData: {
size_t data;
u64 data;
debug_info_stream.read_LEB128_unsigned(data);
VERIFY(!debug_info_stream.has_any_error());
value.type = AttributeValue::Type::UnsignedNumber;
value.data.as_u32 = data;
value.data.as_unsigned = data;
break;
}
case AttributeDataForm::SecOffset: {
@ -130,7 +130,7 @@ AttributeValue DwarfInfo::get_attribute_value(AttributeDataForm form, ssize_t im
debug_info_stream >> data;
VERIFY(!debug_info_stream.has_any_error());
value.type = AttributeValue::Type::SecOffset;
value.data.as_u32 = data;
value.data.as_unsigned = data;
break;
}
case AttributeDataForm::Data4: {
@ -138,15 +138,15 @@ AttributeValue DwarfInfo::get_attribute_value(AttributeDataForm form, ssize_t im
debug_info_stream >> data;
VERIFY(!debug_info_stream.has_any_error());
value.type = AttributeValue::Type::UnsignedNumber;
value.data.as_u32 = data;
value.data.as_unsigned = data;
break;
}
case AttributeDataForm::Data8: {
u64 data;
debug_info_stream >> data;
VERIFY(!debug_info_stream.has_any_error());
value.type = AttributeValue::Type::LongUnsignedNumber;
value.data.as_u64 = data;
value.type = AttributeValue::Type::UnsignedNumber;
value.data.as_unsigned = data;
break;
}
case AttributeDataForm::Ref4: {
@ -155,7 +155,7 @@ AttributeValue DwarfInfo::get_attribute_value(AttributeDataForm form, ssize_t im
VERIFY(!debug_info_stream.has_any_error());
value.type = AttributeValue::Type::DieReference;
VERIFY(unit);
value.data.as_u32 = data + unit->offset();
value.data.as_unsigned = data + unit->offset();
break;
}
case AttributeDataForm::FlagPresent: {
@ -225,7 +225,7 @@ AttributeValue DwarfInfo::get_attribute_value(AttributeDataForm form, ssize_t im
case AttributeDataForm::ImplicitConst: {
/* Value is part of the abbreviation record. */
value.type = AttributeValue::Type::SignedNumber;
value.data.as_i32 = implicit_const_value;
value.data.as_signed = implicit_const_value;
break;
}
default:
@ -250,7 +250,7 @@ void DwarfInfo::build_cached_dies() const
if (!start.has_value() || !end.has_value())
return {};
VERIFY(start->type == Dwarf::AttributeValue::Type::UnsignedNumber);
VERIFY(start->form == Dwarf::AttributeDataForm::Addr);
// DW_AT_high_pc attribute can have different meanings depending on the attribute form.
// (Dwarf version 5, section 2.17.2).
@ -259,9 +259,9 @@ void DwarfInfo::build_cached_dies() const
if (end->form == Dwarf::AttributeDataForm::Addr)
range_end = end->data.as_addr;
else
range_end = start->data.as_u32 + end->data.as_u32;
range_end = start->data.as_unsigned + end->data.as_unsigned;
return { DIERange { start.value().data.as_u32, range_end } };
return { DIERange { (FlatPtr)start.value().data.as_addr, range_end } };
};
// If we simply use a lambda, type deduction fails because it's used recursively.

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

@ -63,7 +63,7 @@ void LineProgram::parse_path_entries(Function<void(PathEntry& entry)> callback,
entry.path = value.data.as_string;
break;
case ContentType::DirectoryIndex:
entry.directory_index = value.data.as_u32;
entry.directory_index = value.data.as_unsigned;
break;
default:
dbgln_if(DWARF_DEBUG, "Unhandled path list attribute: {}", (int)format_description.type);