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[lldb/DWARF] Bypass the compres^Wconstruction of DIERefs in debug_names #93296

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Merged
merged 1 commit into from
May 29, 2024
Merged

[lldb/DWARF] Bypass the compres^Wconstruction of DIERefs in debug_names #93296

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8 changes: 6 additions & 2 deletions lldb/source/Plugins/SymbolFile/DWARF/AppleDWARFIndex.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -284,8 +284,12 @@ void AppleDWARFIndex::GetFunctions(
for (const auto &entry : m_apple_names_up->equal_range(name)) {
DIERef die_ref(std::nullopt, DIERef::Section::DebugInfo,
*entry.getDIESectionOffset());
if (!ProcessFunctionDIE(lookup_info, die_ref, dwarf, parent_decl_ctx,
callback))
DWARFDIE die = dwarf.GetDIE(die_ref);
if (!die) {
ReportInvalidDIERef(die_ref, name);
continue;
}
if (!ProcessFunctionDIE(lookup_info, die, parent_decl_ctx, callback))
return;
}
}
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7 changes: 1 addition & 6 deletions lldb/source/Plugins/SymbolFile/DWARF/DWARFIndex.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -24,16 +24,11 @@ using namespace lldb_private::plugin::dwarf;
DWARFIndex::~DWARFIndex() = default;

bool DWARFIndex::ProcessFunctionDIE(
const Module::LookupInfo &lookup_info, DIERef ref, SymbolFileDWARF &dwarf,
const Module::LookupInfo &lookup_info, DWARFDIE die,
const CompilerDeclContext &parent_decl_ctx,
llvm::function_ref<bool(DWARFDIE die)> callback) {
llvm::StringRef name = lookup_info.GetLookupName().GetStringRef();
FunctionNameType name_type_mask = lookup_info.GetNameTypeMask();
DWARFDIE die = dwarf.GetDIE(ref);
if (!die) {
ReportInvalidDIERef(ref, name);
return true;
}

if (!(name_type_mask & eFunctionNameTypeFull)) {
ConstString name_to_match_against;
Expand Down
9 changes: 4 additions & 5 deletions lldb/source/Plugins/SymbolFile/DWARF/DWARFIndex.h
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Original file line number Diff line number Diff line change
Expand Up @@ -81,11 +81,10 @@ class DWARFIndex {
StatsDuration m_index_time;

/// Helper function implementing common logic for processing function dies. If
/// the function given by "ref" matches search criteria given by
/// "parent_decl_ctx" and "name_type_mask", it is inserted into the "dies"
/// vector.
bool ProcessFunctionDIE(const Module::LookupInfo &lookup_info, DIERef ref,
SymbolFileDWARF &dwarf,
/// the function given by "die" matches search criteria given by
/// "parent_decl_ctx" and "name_type_mask", it calls the callback with the
/// given die.
bool ProcessFunctionDIE(const Module::LookupInfo &lookup_info, DWARFDIE die,
const CompilerDeclContext &parent_decl_ctx,
llvm::function_ref<bool(DWARFDIE die)> callback);

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58 changes: 25 additions & 33 deletions lldb/source/Plugins/SymbolFile/DWARF/DebugNamesDWARFIndex.cpp
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Expand Up @@ -64,27 +64,25 @@ DebugNamesDWARFIndex::GetNonSkeletonUnit(const DebugNames::Entry &entry) const {
return cu ? &cu->GetNonSkeletonUnit() : nullptr;
}

std::optional<DIERef>
DebugNamesDWARFIndex::ToDIERef(const DebugNames::Entry &entry) const {
DWARFDIE DebugNamesDWARFIndex::GetDIE(const DebugNames::Entry &entry) const {
DWARFUnit *unit = GetNonSkeletonUnit(entry);
if (!unit)
return std::nullopt;
if (std::optional<uint64_t> die_offset = entry.getDIEUnitOffset())
return DIERef(unit->GetSymbolFileDWARF().GetFileIndex(),
DIERef::Section::DebugInfo, unit->GetOffset() + *die_offset);

return std::nullopt;
std::optional<uint64_t> die_offset = entry.getDIEUnitOffset();
if (!unit || !die_offset)
return DWARFDIE();
if (DWARFDIE die = unit->GetDIE(unit->GetOffset() + *die_offset))
return die;

m_module.ReportErrorIfModifyDetected(
"the DWARF debug information has been modified (bad offset {0:x} in "
"debug_names section)\n",
*die_offset);
return DWARFDIE();
}

bool DebugNamesDWARFIndex::ProcessEntry(
const DebugNames::Entry &entry,
llvm::function_ref<bool(DWARFDIE die)> callback) {
std::optional<DIERef> ref = ToDIERef(entry);
if (!ref)
return true;
SymbolFileDWARF &dwarf = *llvm::cast<SymbolFileDWARF>(
m_module.GetSymbolFile()->GetBackingSymbolFile());
DWARFDIE die = dwarf.GetDIE(*ref);
DWARFDIE die = GetDIE(entry);
if (!die)
return true;
return callback(die);
Expand Down Expand Up @@ -183,27 +181,22 @@ void DebugNamesDWARFIndex::GetCompleteObjCClass(
llvm::function_ref<bool(DWARFDIE die)> callback) {
// Keep a list of incomplete types as fallback for when we don't find the
// complete type.
DIEArray incomplete_types;
std::vector<DWARFDIE> incomplete_types;
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This can force the parsing early parsing of some units (e.g., if we run into many incomplete types, followed by a complete definition). I don't know how often this happens, but if you think that's an issue, we can fix it by storing the incomplete types as a (DWARFUnit *, die_offset) pair here.

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Let me try to run at least one basic experiment here

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Thanks.


for (const DebugNames::Entry &entry :
m_debug_names_up->equal_range(class_name.GetStringRef())) {
if (entry.tag() != DW_TAG_structure_type &&
entry.tag() != DW_TAG_class_type)
continue;

std::optional<DIERef> ref = ToDIERef(entry);
if (!ref)
continue;

DWARFUnit *cu = m_debug_info.GetUnit(*ref);
if (!cu || !cu->Supports_DW_AT_APPLE_objc_complete_type()) {
incomplete_types.push_back(*ref);
DWARFDIE die = GetDIE(entry);
if (!die) {
// Report invalid
continue;
}

DWARFDIE die = m_debug_info.GetDIE(*ref);
if (!die) {
ReportInvalidDIERef(*ref, class_name.GetStringRef());
DWARFUnit *cu = die.GetCU();
if (!cu->Supports_DW_AT_APPLE_objc_complete_type()) {
incomplete_types.push_back(die);
continue;
}

Expand All @@ -212,12 +205,11 @@ void DebugNamesDWARFIndex::GetCompleteObjCClass(
callback(die);
return;
}
incomplete_types.push_back(*ref);
incomplete_types.push_back(die);
}

auto dierefcallback = DIERefCallback(callback, class_name.GetStringRef());
for (DIERef ref : incomplete_types)
if (!dierefcallback(ref))
for (DWARFDIE die : incomplete_types)
if (!callback(die))
return;

m_fallback.GetCompleteObjCClass(class_name, must_be_implementation, callback);
Expand Down Expand Up @@ -379,8 +371,8 @@ void DebugNamesDWARFIndex::GetFunctions(
if (tag != DW_TAG_subprogram && tag != DW_TAG_inlined_subroutine)
continue;

if (std::optional<DIERef> ref = ToDIERef(entry)) {
if (!ProcessFunctionDIE(lookup_info, *ref, dwarf, parent_decl_ctx,
if (DWARFDIE die = GetDIE(entry)) {
if (!ProcessFunctionDIE(lookup_info, die, parent_decl_ctx,
[&](DWARFDIE die) {
if (!seen.insert(die.GetDIE()).second)
return true;
Expand Down
2 changes: 1 addition & 1 deletion lldb/source/Plugins/SymbolFile/DWARF/DebugNamesDWARFIndex.h
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Original file line number Diff line number Diff line change
Expand Up @@ -84,7 +84,7 @@ class DebugNamesDWARFIndex : public DWARFIndex {
ManualDWARFIndex m_fallback;

DWARFUnit *GetNonSkeletonUnit(const DebugNames::Entry &entry) const;
std::optional<DIERef> ToDIERef(const DebugNames::Entry &entry) const;
DWARFDIE GetDIE(const DebugNames::Entry &entry) const;
bool ProcessEntry(const DebugNames::Entry &entry,
llvm::function_ref<bool(DWARFDIE die)> callback);

Expand Down
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