[Lldb-commits] [lldb] Reapply [lldb][DWARF] Delay struct/class/union definition DIE searching when parsing declaration DIEs. (PR #98361)

[Pavel Labath via lldb-commits]

================
@@ -1631,27 +1638,49 @@ bool SymbolFileDWARF::CompleteType(CompilerType &compiler_type) {
     return true;
   }
 
-  DWARFDIE dwarf_die = GetDIE(die_it->getSecond());
-  if (dwarf_die) {
-    // Once we start resolving this type, remove it from the forward
-    // declaration map in case anyone child members or other types require this
-    // type to get resolved. The type will get resolved when all of the calls
-    // to SymbolFileDWARF::ResolveClangOpaqueTypeDefinition are done.
-    GetForwardDeclCompilerTypeToDIE().erase(die_it);
-
-    Type *type = GetDIEToType().lookup(dwarf_die.GetDIE());
+  DWARFDIE decl_die = GetDIE(die_it->getSecond());
+  // Once we start resolving this type, remove it from the forward
+  // declaration map in case anyone's child members or other types require this
+  // type to get resolved.
+  GetForwardDeclCompilerTypeToDIE().erase(die_it);
+  DWARFDIE def_die = FindDefinitionDIE(decl_die);
+  if (!def_die) {
+    SymbolFileDWARFDebugMap *debug_map_symfile = 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(decl_die);
+    }
+  }
+  if (!def_die) {
+    // If we don't have definition DIE, CompleteTypeFromDWARF will forcefully
+    // complete this type.
+    def_die = decl_die;
+  }
 
-    Log *log = GetLog(DWARFLog::DebugInfo | DWARFLog::TypeCompletion);
-    if (log)
-      GetObjectFile()->GetModule()->LogMessageVerboseBacktrace(
-          log, "{0:x8}: {1} ({2}) '{3}' resolving forward declaration...",
-          dwarf_die.GetID(), DW_TAG_value_to_name(dwarf_die.Tag()),
-          dwarf_die.Tag(), type->GetName().AsCString());
-    assert(compiler_type);
-    if (DWARFASTParser *dwarf_ast = GetDWARFParser(*dwarf_die.GetCU()))
-      return dwarf_ast->CompleteTypeFromDWARF(dwarf_die, type, compiler_type);
+  DWARFASTParser *dwarf_ast = GetDWARFParser(*def_die.GetCU());
+  if (!dwarf_ast)
+    return false;
+  Type *type = GetDIEToType().lookup(decl_die.GetDIE());
+  if (decl_die != def_die) {
+    GetDIEToType()[def_die.GetDIE()] = type;
+    // Need to update Type ID to refer to the definition DIE. because
+    // it's used in ParseCXXMethod to determine if we need to copy cxx
+    // method types from a declaration DIE to this definition DIE.
+    type->SetID(def_die.GetID());
+    if (DWARFASTParserClang *ast_parser =
+            static_cast<DWARFASTParserClang *>(dwarf_ast))
----------------
labath wrote:

this check is superfluous. static_cast will never turn a non-null pointer into nullptr.

https://github.com/llvm/llvm-project/pull/98361