[clang] [llvm] Reland "[DebugMetadata][DwarfDebug] Support function-local types in lexical block scopes (4/7)" (PR #165032)

[Jeremy Morse via llvm-commits]

================
@@ -766,26 +765,41 @@ DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope,
   return ScopeDIE;
 }
 
-// Construct new DW_TAG_lexical_block for this scope and attach
-// DW_AT_low_pc/DW_AT_high_pc labels.
-DIE *DwarfCompileUnit::constructLexicalScopeDIE(LexicalScope *Scope) {
+DIE *DwarfCompileUnit::getOrCreateLexicalBlockDIE(LexicalScope *Scope,
+                                                  DIE &ParentScopeDIE) {
   if (DD->isLexicalScopeDIENull(Scope))
     return nullptr;
   const auto *DS = Scope->getScopeNode();
-
-  auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_lexical_block);
-  if (Scope->isAbstractScope()) {
-    assert(!getAbstractScopeDIEs().count(DS) &&
-           "Abstract DIE for this scope exists!");
-    getAbstractScopeDIEs()[DS] = ScopeDIE;
-    return ScopeDIE;
+  DIE *ScopeDIE = nullptr;
+
+  // FIXME: We may have a concrete DIE for this scope already created.
+  // This may happen when we emit local variables for an abstract tree of
+  // an inlined function: if a local variable has a templated type with
+  // a function-local type as a template parameter. See PR55680 for details
+  // (see also llvm/test/DebugInfo/Generic/local-type-as-template-parameter.ll).
----------------
jmorse wrote:

It's unclear what's to be fixed here: the concrete DIE isn't supposed to exist already but we accept it temporarily, or we should intend on creating a duplicate, or placing it somewhere else?

https://github.com/llvm/llvm-project/pull/165032