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[lldb][DWARF] Fix adding children to clang type that hasn't started definition. #93839

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Merged
merged 4 commits into from
May 30, 2024
Merged

[lldb][DWARF] Fix adding children to clang type that hasn't started definition. #93839

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90cbcf8
[lldb][DWARF] Do not differentiate DW_TAG_class_type and DW_TAG_struc…
ZequanWu May 30, 2024
d78b4d1
Just assert if c/c++ clang_type is not being defined in DWARFASTParse…
ZequanWu May 30, 2024
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ZequanWu May 30, 2024
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4 changes: 4 additions & 0 deletions lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2232,6 +2232,10 @@ bool DWARFASTParserClang::CompleteRecordType(const DWARFDIE &die,
// For objective C we don't start the definition when the class is
// created.
TypeSystemClang::StartTagDeclarationDefinition(clang_type);
} else {
assert(clang_type.IsBeingDefined() &&
"Trying to complete a definition without a prior call to "
"StartTagDeclarationDefinition.");
}

AccessType default_accessibility = eAccessNone;
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12 changes: 10 additions & 2 deletions lldb/source/Plugins/SymbolFile/DWARF/UniqueDWARFASTType.cpp
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Expand Up @@ -13,12 +13,18 @@
using namespace lldb_private::dwarf;
using namespace lldb_private::plugin::dwarf;

static bool IsStructOrClassTag(llvm::dwarf::Tag Tag) {
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I think we have this function somewhere already. Might be worth checking (possibly even in the llvm headers?)

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Ah yes in SymbolFileDWARF::FindDefinitionTypeForDWARFDeclContext we have the same kind of check. Maybe one could consolidate those in one API? But might not be worth the churn, so feel free to ignore

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It's here:

llvm-project/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

Line 136 in ed35a92

bool IsStructOrClassTag(llvm::dwarf::Tag Tag) {
, maybe move it to namespace lldb_private::plugin::dwarf?

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Are there more tag equality checks around LLDB that could benefit from re-using the following check:

udt.m_die.Tag() == die.Tag() || (IsStructOrClassTag(udt.m_die.Tag()) &&
                                         IsStructOrClassTag(die.Tag()))

There's at least two now. Not sure where we'd put such an API. Perhaps @felipepiovezan or @adrian-prantl have some input on this.

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Yeah, we can probably do it in a different change.

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@Michael137 Michael137 May 30, 2024 •
edited
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There's also

/// Returns true if `tag` is a class_type of structure_type tag.  
static bool IsClassOrStruct(dw_tag_t tag) {                       
  return tag == DW_TAG_class_type || tag == DW_TAG_structure_type;
}

In AppleDWARFIndex FYI

And it uses that for the same type of check:

 return tag == expected_tag ||                                         
        (IsClassOrStruct(tag) && IsClassOrStruct(expected_tag));

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Yeah, we definitely need to clean all of these up.
There might be one inside llvm/ too..

return Tag == llvm::dwarf::Tag::DW_TAG_class_type ||
Tag == llvm::dwarf::Tag::DW_TAG_structure_type;
}

UniqueDWARFASTType *UniqueDWARFASTTypeList::Find(
const DWARFDIE &die, const lldb_private::Declaration &decl,
const int32_t byte_size, bool is_forward_declaration) {
for (UniqueDWARFASTType &udt : m_collection) {
// Make sure the tags match
if (udt.m_die.Tag() == die.Tag()) {
if (udt.m_die.Tag() == die.Tag() || (IsStructOrClassTag(udt.m_die.Tag()) &&
IsStructOrClassTag(die.Tag()))) {
// If they are not both definition DIEs or both declaration DIEs, then
// don't check for byte size and declaration location, because declaration
// DIEs usually don't have those info.
Expand All @@ -39,7 +45,9 @@ UniqueDWARFASTType *UniqueDWARFASTTypeList::Find(
while (!done && match && parent_arg_die && parent_pos_die) {
const dw_tag_t parent_arg_tag = parent_arg_die.Tag();
const dw_tag_t parent_pos_tag = parent_pos_die.Tag();
if (parent_arg_tag == parent_pos_tag) {
if (parent_arg_tag == parent_pos_tag ||
(IsStructOrClassTag(parent_arg_tag) &&
IsStructOrClassTag(parent_pos_tag))) {
switch (parent_arg_tag) {
case DW_TAG_class_type:
case DW_TAG_structure_type:
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