Allow DIDerivedType as a bound in DISubrangeType

llvm/include/llvm/IR/DebugInfoMetadata.h

@@ -1520,7 +1520,9 @@ inline bool operator!=(DIDerivedType::PtrAuthData Lhs,
 /// is also a DIType.
 class DISubrangeType : public DIType {
 public:
-  typedef PointerUnion<ConstantInt *, DIVariable *, DIExpression *> BoundType;
+  typedef PointerUnion<ConstantInt *, DIVariable *, DIExpression *,
+                       DIDerivedType *>
+      BoundType;
 
 private:
   friend class LLVMContextImpl;

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp

@@ -1607,6 +1607,9 @@ void DwarfUnit::constructSubrangeDIE(DIE &DW_Subrange, const DISubrangeType *SR,
     if (auto *BV = dyn_cast_if_present<DIVariable *>(Bound)) {
       if (auto *VarDIE = getDIE(BV))
         addDIEEntry(DW_Subrange, Attr, *VarDIE);
+    } else if (auto *DT = dyn_cast_if_present<DIDerivedType *>(Bound)) {
+      if (auto *DTDIE = getDIE(DT))
+        addDIEEntry(DW_Subrange, Attr, *DTDIE);
     } else if (auto *BE = dyn_cast_if_present<DIExpression *>(Bound)) {
       DIELoc *Loc = new (DIEValueAllocator) DIELoc;
       DIEDwarfExpression DwarfExpr(*Asm, getCU(), *Loc);

llvm/lib/IR/DebugInfoMetadata.cpp

@@ -839,7 +839,7 @@ DISubrangeType::convertRawToBound(Metadata *IN) const {
     return BoundType();
 
   assert(isa<ConstantAsMetadata>(IN) || isa<DIVariable>(IN) ||
-         isa<DIExpression>(IN));
+         isa<DIExpression>(IN) || isa<DIDerivedType>(IN));
 
   if (auto *MD = dyn_cast<ConstantAsMetadata>(IN))
     return BoundType(cast<ConstantInt>(MD->getValue()));
@@ -850,6 +850,9 @@ DISubrangeType::convertRawToBound(Metadata *IN) const {
   if (auto *MD = dyn_cast<DIExpression>(IN))
     return BoundType(MD);
 
+  if (auto *DT = dyn_cast<DIDerivedType>(IN))
+    return BoundType(DT);
+
   return BoundType();
 }
 

llvm/lib/IR/Verifier.cpp

@@ -1187,13 +1187,17 @@ void Verifier::visitDISubrangeType(const DISubrangeType &N) {
   CheckDI(!BaseType || isType(BaseType), "BaseType must be a type");
   auto *LBound = N.getRawLowerBound();
   CheckDI(!LBound || isa<ConstantAsMetadata>(LBound) ||
-              isa<DIVariable>(LBound) || isa<DIExpression>(LBound),
-          "LowerBound must be signed constant or DIVariable or DIExpression",
+              isa<DIVariable>(LBound) || isa<DIExpression>(LBound) ||
+              isa<DIDerivedType>(LBound),
+          "LowerBound must be signed constant or DIVariable or DIExpression or "
+          "DIDerivedType",
           &N);
   auto *UBound = N.getRawUpperBound();
   CheckDI(!UBound || isa<ConstantAsMetadata>(UBound) ||
-              isa<DIVariable>(UBound) || isa<DIExpression>(UBound),
-          "UpperBound must be signed constant or DIVariable or DIExpression",
+              isa<DIVariable>(UBound) || isa<DIExpression>(UBound) ||
+              isa<DIDerivedType>(UBound),
+          "UpperBound must be signed constant or DIVariable or DIExpression or "
+          "DIDerivedType",
           &N);
   auto *Stride = N.getRawStride();
   CheckDI(!Stride || isa<ConstantAsMetadata>(Stride) ||

llvm/test/DebugInfo/X86/derived-in-subrange.ll

@@ -0,0 +1,88 @@
+; RUN: llvm-as < %s | llvm-dis | llc -mtriple=x86_64 -O0 -filetype=obj -o - | llvm-dwarfdump -v -debug-info - | FileCheck %s
+
+; A test to verify the use of a DIDerivedType as a bound of a
+; DISubrangeType.
+
+; CHECK: DW_TAG_array_type
+; CHECK-NEXT: DW_AT_type [DW_FORM_ref4] {{.*}}
+; CHECK: DW_TAG_subrange_type {{.*}}
+; CHECK-NEXT: DW_AT_type [DW_FORM_ref4] {{.*}}
+; CHECK-NEXT: DW_AT_upper_bound [DW_FORM_ref4] {{.*}}
+
+; ModuleID = 'vla.ads'
+source_filename = "vla.ads"
+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"
+
+%vla__array_type_FP = type { ptr, ptr }
+%vla__record_type_I = type <{ i32 }>
+
+@vla_E = dso_local global i16 0, align 2, !dbg !0
+
+; Function Attrs: inlinehint
+define dso_local void @vla__array_typeIP(%vla__array_type_FP %_init) #0 !dbg !10 {
+entry:
+  %0 = extractvalue %vla__array_type_FP %_init, 1, !dbg !15
+  %1 = call ptr @llvm.invariant.start.p0(i64 8, ptr %0), !dbg !15
+  ret void, !dbg !15
+}
+
+; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+declare ptr @llvm.invariant.start.p0(i64 immarg, ptr nocapture) #1
+
+; Function Attrs: inlinehint
+define dso_local void @vla__record_typeIP(ptr noalias nocapture nonnull %_init, i32 %l1) #0 !dbg !16 {
+entry:
+    #dbg_declare(ptr %_init, !31, !DIExpression(), !32)
+    #dbg_value(i32 %l1, !33, !DIExpression(), !34)
+  %0 = getelementptr inbounds %vla__record_type_I, ptr %_init, i32 0, i32 0, !dbg !32
+  store i32 %l1, ptr %0, align 4, !dbg !32, !tbaa !35
+  ret void, !dbg !32
+}
+
+attributes #0 = { inlinehint }
+attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+
+!llvm.module.flags = !{!6, !7, !8, !9}
+!llvm.dbg.cu = !{!2}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "vla_E", scope: !2, file: !3, line: 16, type: !5, isLocal: false, isDefinition: true, align: 16)
+!2 = distinct !DICompileUnit(language: DW_LANG_Ada95, file: !3, producer: "GNAT/LLVM", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false)
+!3 = !DIFile(filename: "vla.ads", directory: "")
+!4 = !{!0}
+!5 = !DIBasicType(name: "short_integer", size: 16, encoding: DW_ATE_signed)
+!6 = !{i32 8, !"PIC Level", i32 2}
+!7 = !{i32 7, !"PIE Level", i32 2}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !{i32 2, !"Dwarf Version", i32 4}
+!10 = distinct !DISubprogram(name: "vla__array_typeIP", scope: !3, file: !3, line: 17, type: !11, scopeLine: 17, spFlags: DISPFlagDefinition, unit: !2)
+!11 = !DISubroutineType(types: !12)
+!12 = !{null, !13}
+!13 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !14, size: 64, align: 64, dwarfAddressSpace: 0)
+!14 = !DIBasicType(tag: DW_TAG_unspecified_type, name: "vla__array_type")
+!15 = !DILocation(line: 17, column: 9, scope: !10)
+!16 = distinct !DISubprogram(name: "vla__record_typeIP", scope: !3, file: !3, line: 18, type: !17, scopeLine: 18, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !30)
+!17 = !DISubroutineType(types: !18)
+!18 = !{null, !19, !23}
+!19 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !20, size: 64, align: 64, dwarfAddressSpace: 0)
+!20 = !DICompositeType(tag: DW_TAG_structure_type, name: "vla__record_type", file: !3, line: 18, size: !DIExpression(DW_OP_push_object_address, DW_OP_deref_size, 4, DW_OP_constu, 32, DW_OP_mul, DW_OP_constu, 32, DW_OP_plus), align: 32, elements: !21, identifier: "vla__record_type")
+!21 = !{!22, !26}
+!22 = !DIDerivedType(tag: DW_TAG_member, name: "l1", file: !3, line: 18, baseType: !23)
+!23 = !DISubrangeType(name: "natural", file: !24, line: 1, size: 32, align: 32, baseType: !25, lowerBound: i64 0, upperBound: i64 2147483647)
+!24 = !DIFile(filename: "system.ads", directory: "/home/tromey/AdaCore/gnat-llvm/llvm-interface//lib/gnat-llvm/x86_64-unknown-linux-gnu/rts-native/adainclude/")
+!25 = !DIBasicType(name: "integer", size: 32, encoding: DW_ATE_signed)
+!26 = !DIDerivedType(tag: DW_TAG_member, name: "a1", file: !3, line: 19, baseType: !27, offset: 32)
+!27 = !DICompositeType(tag: DW_TAG_array_type, scope: !20, file: !3, line: 19, baseType: !25, align: 32, elements: !28)
+!28 = !{!29}
+!29 = !DISubrangeType(baseType: !25, lowerBound: i64 1, upperBound: !22)
+!30 = !{}
+!31 = !DILocalVariable(name: "_init", arg: 1, scope: !16, file: !3, line: 18, type: !20, flags: DIFlagArtificial)
+!32 = !DILocation(line: 18, column: 9, scope: !16)
+!33 = !DILocalVariable(name: "l1", arg: 2, scope: !16, file: !3, line: 18, type: !23, flags: DIFlagArtificial)
+!34 = !DILocation(line: 18, column: 22, scope: !16)
+!35 = !{!36, !36, i64 0, i64 4}
+!36 = !{!37, i64 4, !"natural#T5"}
+!37 = !{!38, i64 4, !"natural#TN"}
+!38 = !{!39, i64 4, !"integerB#TN"}
+!39 = !{!"Ada Root"}