[Lldb-commits] [lldb] [WIP][lldb][DWARFASTParserClang] Eagerly search definitions for Objective-C classes (PR #119860)

[Adrian Prantl via lldb-commits]

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@@ -1671,43 +1671,84 @@ DWARFASTParserClang::ParseStructureLikeDIE(const SymbolContext &sc,
     attrs.is_forward_declaration = true;
   }
 
+  DWARFDIE def_die;
+  if (attrs.is_forward_declaration && cu_language == eLanguageTypeObjC) {
+    def_die = dwarf->FindDefinitionDIE(die);
+
+    if (!def_die) {
+      SymbolFileDWARFDebugMap *debug_map_symfile = dwarf->GetDebugMapSymfile();
+      if (debug_map_symfile) {
+        // We weren't able to find a full declaration in this DWARF,
+        // see if we have a declaration anywhere else...
+        def_die = debug_map_symfile->FindDefinitionDIE(die);
+      }
+    }
+
+    if (log) {
+      dwarf->GetObjectFile()->GetModule()->LogMessage(
+          log,
+          "SymbolFileDWARF({0:p}) - {1:x16}}: {2} ({3}) type \"{4}\" is a "
+          "forward declaration, complete DIE is {5}",
+          static_cast<void *>(this), die.GetID(), DW_TAG_value_to_name(tag),
+          tag, attrs.name.GetCString(),
+          def_die ? llvm::utohexstr(def_die.GetID()) : "not found");
+    }
+
+    if (def_die) {
+      if (auto [it, inserted] = dwarf->GetDIEToType().try_emplace(
+              def_die.GetDIE(), DIE_IS_BEING_PARSED);
+          !inserted) {
+        if (it->getSecond() == nullptr ||
+            it->getSecond() == DIE_IS_BEING_PARSED)
+          return nullptr;
+        return it->getSecond()->shared_from_this();
+      }
+      attrs = ParsedDWARFTypeAttributes(def_die);
+    }
+  }
+
+  if (!def_die)
+    def_die = die;
+
   if (attrs.name) {
-    GetUniqueTypeNameAndDeclaration(die, cu_language, unique_typename,
+    GetUniqueTypeNameAndDeclaration(def_die, cu_language, unique_typename,
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adrian-prantl wrote:

I find the name def_die misleading here. IIUC, it *may* be a def die if the block above was run and successful?

https://github.com/llvm/llvm-project/pull/119860