================
@@ -374,25 +377,40 @@ void DebugNamesDWARFIndex::GetFullyQualifiedType(
m_fallback.GetFullyQualifiedType(context, callback);
}
+bool DebugNamesDWARFIndex::SameAsEntryATName(
+ llvm::StringRef query_name, const DebugNames::Entry &entry) const {
+ auto maybe_dieoffset = entry.getDIEUnitOffset();
+ if (!maybe_dieoffset)
+ return false;
+
+ // [Optimization] instead of parsing the entry from dwo file, we simply
+ // check if the query_name can point to an entry of the same DIE offset.
+ // This greatly reduced number of dwo file parsed and thus improved the
+ // performance.
+ for (const DebugNames::Entry &query_entry :
+ entry.getNameIndex()->equal_range(query_name)) {
+ auto query_dieoffset = query_entry.getDIEUnitOffset();
+ if (!query_dieoffset)
+ continue;
+
+ if (*query_dieoffset == *maybe_dieoffset) {
+ return true;
+ } else if (*query_dieoffset > *maybe_dieoffset) {
+ // The pool entries of the same name are sequentially cluttered together
+ // so if the query name from `query_name` is after the target entry, this
+ // is definitely not the correct one, we can stop searching.
+ return false;
+ }
+ }
+ return false;
+}
+
bool DebugNamesDWARFIndex::SameParentChain(
llvm::ArrayRef<llvm::StringRef> parent_names,
llvm::ArrayRef<DebugNames::Entry> parent_entries) const {
-
if (parent_entries.size() != parent_names.size())
return false;
- auto SameAsEntryATName = [this](llvm::StringRef name,
- const DebugNames::Entry &entry) {
- // Peek at the AT_name of `entry` and test equality to `name`.
- auto maybe_dieoffset = entry.getDIEUnitOffset();
- if (!maybe_dieoffset)
- return false;
- DWARFUnit *unit = GetNonSkeletonUnit(entry);
- if (!unit)
- return false;
- return name == unit->PeekDIEName(unit->GetOffset() + *maybe_dieoffset);
----------------
felipepiovezan wrote:
I think this is the core of your proposal, right? In the original
implementation that I did, the vast majority of the savings was thanks to being
able to do `PeekDIEName`. I would strongly recommend we benchmark this new
implementation is the non-dwo case as well.
One way to check is to build with regular object files (the non dwo case) and
repeat the experiments I described in this reply:
https://discourse.llvm.org/t/rfc-improve-dwarf-5-debug-names-type-lookup-parsing-speed/74151/38?u=felipe
And instrumenting this portion of the code:
https://github.com/llvm/llvm-project/pull/75365/commits/837bc0f476820f9ee5695223420105dedfea8d79
https://github.com/llvm/llvm-project/pull/108907
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