[LLVM][DWARF] Create debug names entry for non-tu top level DIE

LLVM tries to create TU optimistically. If that fails it discards the TU
state and creates TU wihin the CU. When this happens the entry in debug
names table for top level DIE is not created. This causes
llvm-dwarfdumjp --debug-names --verify to fail because an entry is
missing. This patch adds a call to updateAcceleratorTables, when TU
creation fails.

Author: ayermolo

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -3704,19 +3704,19 @@ uint64_t DwarfDebug::makeTypeSignature(StringRef Identifier) {
   return Result.high();
 }
 
-void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
+bool DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
                                       StringRef Identifier, DIE &RefDie,
                                       const DICompositeType *CTy) {
   // Fast path if we're building some type units and one has already used the
   // address pool we know we're going to throw away all this work anyway, so
   // don't bother building dependent types.
   if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
-    return;
+    return false;
 
   auto Ins = TypeSignatures.insert(std::make_pair(CTy, 0));
   if (!Ins.second) {
     CU.addDIETypeSignature(RefDie, Ins.first->second);
-    return;
+    return false;
   }
 
   setCurrentDWARF5AccelTable(DWARF5AccelTableKind::TU);
@@ -3789,7 +3789,7 @@ void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
       // they depend on addresses, throwing them out and rebuilding them.
       setCurrentDWARF5AccelTable(DWARF5AccelTableKind::CU);
       CU.constructTypeDIE(RefDie, cast<DICompositeType>(CTy));
-      return;
+      return true;
     }
 
     // If the type wasn't dependent on fission addresses, finish adding the type
@@ -3811,6 +3811,7 @@ void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
     setCurrentDWARF5AccelTable(DWARF5AccelTableKind::CU);
   }
   CU.addDIETypeSignature(RefDie, Signature);
+  return false;
 }
 
 // Add the Name along with its companion DIE to the appropriate accelerator

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h

@@ -744,7 +744,8 @@ class DwarfDebug : public DebugHandlerBase {
 
   /// Add a DIE to the set of types that we're going to pull into
   /// type units.
-  void addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
+  /// Returns true if TU creation fails, and type was emitted in the CU.
+  bool addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
                             DIE &Die, const DICompositeType *CTy);
 
   /// Add a label so that arange data can be generated for it.

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp

@@ -589,7 +589,8 @@ DIE *DwarfUnit::createTypeDIE(const DIScope *Context, DIE &ContextDIE,
       // Skip updating the accelerator tables since this is not the full type.
       if (MDString *TypeId = CTy->getRawIdentifier()) {
         addGlobalType(Ty, TyDIE, Context);
-        DD->addDwarfTypeUnitType(getCU(), TypeId->getString(), TyDIE, CTy);
+        if (DD->addDwarfTypeUnitType(getCU(), TypeId->getString(), TyDIE, CTy))
+          updateAcceleratorTables(Context, Ty, TyDIE);
       } else {
         updateAcceleratorTables(Context, Ty, TyDIE);
         finishNonUnitTypeDIE(TyDIE, CTy);

llvm/test/DebugInfo/X86/dwarf5-debug-names-addr-tu-to-non-tu.ll

@@ -0,0 +1,83 @@
+; RUN: llc -filetype=obj -O0 -generate-type-units -mtriple=x86_64-unknown-linux-gnu < %s \
+; RUN:     | llvm-dwarfdump -debug-info -debug-names - \
+; RUN:     | FileCheck %s
+
+;; Test that an entry in the debug names table gets created for a top level DIE when the creation of TU is aborted.
+
+; CHECK: [[OFFSET:0x[0-9a-f]*]]:   DW_TAG_structure_type
+; CHECK: [[OFFSET1:0x[0-9a-f]*]]:   DW_TAG_structure_type
+
+; CHECK:        Bucket 0 [
+; CHECK-NEXT:    Name 1 {
+; CHECK-NEXT:      Hash: {{.+}}
+; CHECK-NEXT:      String: {{.+}} "t3"
+; CHECK-NEXT:      Entry @ {{.+}} {
+; CHECK-NEXT:        Abbrev: 0x1
+; CHECK-NEXT:        Tag: DW_TAG_structure_type
+; CHECK-NEXT:        DW_IDX_die_offset: [[OFFSET]]
+; CHECK-NEXT:        DW_IDX_parent: <parent not indexed>
+
+; CHECK:        Name 5 {
+; CHECK-NEXT:      Hash: {{.+}}
+; CHECK-NEXT:      String: {{.+}} "t2<&foo>"
+; CHECK-NEXT:      Entry @ 0xe1 {
+; CHECK-NEXT:        Abbrev: 0x1
+; CHECK-NEXT:        Tag: DW_TAG_structure_type
+; CHECK-NEXT:        DW_IDX_die_offset: [[OFFSET1]]
+; CHECK-NEXT:        DW_IDX_parent: <parent not indexed>
+
+;; clang++ -O0 main.cpp -gdwarf-5 -fdebug-types-section -gpubnames -S -emit-llvm -glldb -o main.ll
+;; int foo;
+;; namespace {
+;; struct t1 {};
+;; } // namespace
+;; template <int *> struct t2 {
+;;   t1 v1;
+;; };
+;; struct t3 {
+;;   t2<&foo> v1;
+;; };
+;; t3 v1;
+
+; ModuleID = 'main.cpp'
+source_filename = "main.cpp"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%struct.t3 = type { i8 }
+
+@foo = dso_local global i32 0, align 4, !dbg !0
+@v1 = dso_local global %struct.t3 zeroinitializer, align 1, !dbg !5
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!20, !21, !22, !23, !24, !25, !26}
+!llvm.ident = !{!27}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "foo", scope: !2, file: !3, line: 1, type: !19, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, producer: "clang version 20.0.0git ([email protected]:llvm/llvm-project.git ba373096e8ac83a7136fc44bc4e71a7bc53417a6)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, sysroot: "/")
+!3 = !DIFile(filename: "main.cpp", directory: "/StructuredType", checksumkind: CSK_MD5, checksum: "f91f8d905197b1c0309da9526bc4776e")
+!4 = !{!0, !5}
+!5 = !DIGlobalVariableExpression(var: !6, expr: !DIExpression())
+!6 = distinct !DIGlobalVariable(name: "v1", scope: !2, file: !3, line: 11, type: !7, isLocal: false, isDefinition: true)
+!7 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t3", file: !3, line: 8, size: 8, flags: DIFlagTypePassByValue, elements: !8, identifier: "_ZTS2t3")
+!8 = !{!9}
+!9 = !DIDerivedType(tag: DW_TAG_member, name: "v1", scope: !7, file: !3, line: 9, baseType: !10, size: 8)
+!10 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t2<&foo>", file: !3, line: 5, size: 8, flags: DIFlagTypePassByValue, elements: !11, templateParams: !16, identifier: "_ZTS2t2IXadL_Z3fooEEE")
+!11 = !{!12}
+!12 = !DIDerivedType(tag: DW_TAG_member, name: "v1", scope: !10, file: !3, line: 6, baseType: !13, size: 8)
+!13 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t1", scope: !14, file: !3, line: 3, size: 8, flags: DIFlagTypePassByValue, elements: !15)
+!14 = !DINamespace(scope: null)
+!15 = !{}
+!16 = !{!17}
+!17 = !DITemplateValueParameter(type: !18, value: ptr @foo)
+!18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !19, size: 64)
+!19 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!20 = !{i32 7, !"Dwarf Version", i32 5}
+!21 = !{i32 2, !"Debug Info Version", i32 3}
+!22 = !{i32 1, !"wchar_size", i32 4}
+!23 = !{i32 8, !"PIC Level", i32 2}
+!24 = !{i32 7, !"PIE Level", i32 2}
+!25 = !{i32 7, !"uwtable", i32 2}
+!26 = !{i32 7, !"frame-pointer", i32 2}
+!27 = !{!"clang version 20.0.0git ([email protected]:llvm/llvm-project.git ba373096e8ac83a7136fc44bc4e71a7bc53417a6)"}