[PATCH] D30484: [DWARF] Default lower bound should respect requested DWARF version

[Paul Robinson via Phabricator via llvm-commits]

probinson created this revision.
Herald added a subscriber: mehdi_amini.

DWARF defines a default lower-bound for arrays in the set of languages defined for a particular DWARF version.
But the logic to suppress an unnecessary lower-bound attribute was looking at the hard-coded default DWARF version, not the version that had been requested.


https://reviews.llvm.org/D30484

Files:
  lib/CodeGen/AsmPrinter/DwarfUnit.cpp
  test/DebugInfo/X86/default-subrange-array.ll


Index: test/DebugInfo/X86/default-subrange-array.ll
===================================================================
--- test/DebugInfo/X86/default-subrange-array.ll
+++ test/DebugInfo/X86/default-subrange-array.ll
@@ -0,0 +1,53 @@
+; RUN: llc -mtriple=x86_64-apple-darwin -O0 -filetype=obj -dwarf-version 4 \
+; RUN:     -o - < %s | llvm-dwarfdump - -debug-dump=info \
+; RUN:     | FileCheck %s -check-prefixes=CHECK,DWARF4
+; RUN: llc -mtriple=x86_64-apple-darwin -O0 -filetype=obj -dwarf-version 5 \
+; RUN:     -o - < %s | llvm-dwarfdump - -debug-dump=info \
+; RUN:     | FileCheck %s -check-prefixes=CHECK,DWARF5
+
+; Check that we can omit default array lower-bounds.
+; DW_LANG_C_plus_plus_11 is new in DWARF v5, so if we use that with
+; DWARF v4, we should get the DW_AT_lower_bound attribute.
+
+source_filename = "test/DebugInfo/X86/default-subrange-array.ll"
+
+%class.A = type { [42 x i32] }
+
+ at a = global %class.A zeroinitializer, align 4, !dbg !0
+
+; CHECK:       DW_TAG_class_type
+; CHECK:         DW_TAG_member
+; CHECK-NEXT:      DW_AT_name {{.*}} "x"
+; CHECK-NEXT:      DW_AT_type [DW_FORM_ref4] {{.*}} => {[[ARRAY:0x[0-9a-f]+]]})
+
+; CHECK: [[ARRAY]]: DW_TAG_array_type
+; CHECK-NEXT:         DW_AT_type
+; CHECK:            DW_TAG_subrange_type
+; CHECK-NEXT:         DW_AT_type
+; DWARF4-NEXT:        DW_AT_lower_bound [DW_FORM_data1] (0x00)
+; CHECK-NEXT:         DW_AT_count [DW_FORM_data1]       (0x2a)
+; DWARF5-NOT:         DW_AT_lower_bound
+
+
+!llvm.dbg.cu = !{!14}
+!llvm.module.flags = !{!17}
+
+!0 = !DIGlobalVariableExpression(var: !1)
+!1 = !DIGlobalVariable(name: "a", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true)
+!2 = !DIFile(filename: "t.cpp", directory: "/Volumes/Sandbox/llvm")
+!3 = !DICompositeType(tag: DW_TAG_class_type, name: "A", file: !2, line: 1, align: 32, elements: !4)
+!4 = !{!5, !10}
+!5 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !3, file: !2, line: 1, baseType: !6, flags: DIFlagPrivate)
+!6 = !DICompositeType(tag: DW_TAG_array_type, baseType: !7, align: 32, elements: !8)
+!7 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!8 = !{!9}
+!9 = !DISubrange(count: 42, lowerBound: 0)
+!10 = !DISubprogram(name: "A", scope: !3, file: !2, line: 1, type: !11, isLocal: false, isDefinition: false, scopeLine: 1, virtualIndex: 6, flags: DIFlagArtificial | DIFlagPrototyped, isOptimized: false)
+!11 = !DISubroutineType(types: !12)
+!12 = !{null, !13}
+!13 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !3, size: 64, align: 64, flags: DIFlagArtificial | DIFlagObjectPointer)
+!14 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_11, file: !2, producer: "clang version 3.3 (trunk 169136)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !15, retainedTypes: !15, globals: !16, imports: !15)
+!15 = !{}
+!16 = !{!0}
+!17 = !{i32 1, !"Debug Info Version", i32 3}
+
Index: lib/CodeGen/AsmPrinter/DwarfUnit.cpp
===================================================================
--- lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -116,7 +116,7 @@
   case dwarf::DW_LANG_Python:
   case dwarf::DW_LANG_UPC:
   case dwarf::DW_LANG_D:
-    if (dwarf::DWARF_VERSION >= 4)
+    if (DD->getDwarfVersion() >= 4)
       return 0;
     break;
 
@@ -127,7 +127,7 @@
   case dwarf::DW_LANG_Modula2:
   case dwarf::DW_LANG_Pascal83:
   case dwarf::DW_LANG_PLI:
-    if (dwarf::DWARF_VERSION >= 4)
+    if (DD->getDwarfVersion() >= 4)
       return 1;
     break;
 
@@ -143,15 +143,15 @@
   case dwarf::DW_LANG_Swift:
   case dwarf::DW_LANG_Dylan:
   case dwarf::DW_LANG_C_plus_plus_14:
-    if (dwarf::DWARF_VERSION >= 5)
+    if (DD->getDwarfVersion() >= 5)
       return 0;
     break;
 
   case dwarf::DW_LANG_Modula3:
   case dwarf::DW_LANG_Julia:
   case dwarf::DW_LANG_Fortran03:
   case dwarf::DW_LANG_Fortran08:
-    if (dwarf::DWARF_VERSION >= 5)
+    if (DD->getDwarfVersion() >= 5)
       return 1;
     break;
   }


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D30484.90112.patch
Type: text/x-patch
Size: 4010 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20170301/2ce967a1/attachment.bin>