Emit DW_OP_piece also if the previous value was a constant.

This fixes a bug in the DWARF backend.

llvm-svn: 285826

2 files changed, 120 insertions, 2 deletions

diff --git a/llvm/test/DebugInfo/X86/PR26148.ll b/llvm/test/DebugInfo/X86/PR26148.ll
index c93078208ca..62c3157da46 100644
--- a/llvm/test/DebugInfo/X86/PR26148.ll
+++ b/llvm/test/DebugInfo/X86/PR26148.ll
@@ -21,10 +21,12 @@
 ;
 ; CHECK: 0x00000025: Beginning address offset: 0x0000000000000004
 ; CHECK:                Ending address offset: 0x0000000000000004
-; CHECK:                 Location description: 10 03 55 93 04
+; CHECK:                 Location description: 10 03 93 04 55 93 04
+; constu 0x00000003, piece 0x00000004, rdi, piece 0x00000004
 ; CHECK:             Beginning address offset: 0x0000000000000004
 ; CHECK:                Ending address offset: 0x0000000000000014
-; CHECK:                 Location description: 10 03 10 00
+; CHECK:                 Location description: 10 03 93 04 10 00
+; constu 0x00000003, piece 0x00000004, constu 0x00000000, piece 0x00000004
 
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.11.0"
diff --git a/llvm/test/DebugInfo/X86/stack-value-piece.ll b/llvm/test/DebugInfo/X86/stack-value-piece.ll
new file mode 100644
index 00000000000..503ccb3af17
--- /dev/null
+++ b/llvm/test/DebugInfo/X86/stack-value-piece.ll
@@ -0,0 +1,116 @@
+; RUN: llc %s -filetype=obj -o - | llvm-dwarfdump - | FileCheck %s
+; Test that DW_OP_piece is emitted for constants.
+;
+; // Generated from:
+; typedef struct { int a, b; } I;
+; I i(int i) {
+;   I r = {i, 0};
+;   return r;
+; }
+;  
+; typedef struct { float a, b; } F;
+; F f(float f) {
+;   F r = {f, 0};
+;   return r;
+; }
+
+; CHECK: .debug_info contents:
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_name {{.*}} "i"
+; CHECK:   DW_TAG_variable
+; CHECK-NEXT:   DW_AT_location {{.*}} ([[I:.*]])
+; CHECK-NEXT:   DW_AT_name {{.*}} "r"
+;
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_name {{.*}} "f"
+; CHECK:   DW_TAG_variable
+; CHECK-NEXT:   DW_AT_location {{.*}} ([[F:.*]])
+; CHECK-NEXT:   DW_AT_name {{.*}} "r"
+;
+; CHECK: .debug_loc contents:
+; CHECK: [[I]]: Beginning address offset:
+; CHECK-NEXT:           Ending address offset:
+; CHECK-NEXT:            Location description: 55 93 04 10 00 9f 93 04 
+; rdi, piece 0x00000004, constu 0x00000000, stack-value, piece 0x00000004
+;
+; CHECK: [[F]]: Beginning address offset:
+; CHECK-NEXT:           Ending address offset:
+; CHECK-NEXT:            Location description: 61 93 04 10 00 9f 93 04
+; reg17, piece 0x00000004, constu 0x00000000, stack-value, piece 0x00000004
+
+source_filename = "stack-value-piece.c"
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.12.0"
+
+%struct.I = type { i32, i32 }
+%struct.F = type { float, float }
+
+; Function Attrs: nounwind readnone ssp uwtable
+define i64 @i(i32 %i) local_unnamed_addr #0 !dbg !7 {
+entry:
+  tail call void @llvm.dbg.value(metadata i32 %i, i64 0, metadata !18, metadata !22), !dbg !21
+  tail call void @llvm.dbg.value(metadata i32 0, i64 0, metadata !18, metadata !23), !dbg !21
+  %retval.sroa.0.0.insert.ext = zext i32 %i to i64, !dbg !24
+  ret i64 %retval.sroa.0.0.insert.ext, !dbg !24
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: nounwind readnone ssp uwtable
+define <2 x float> @f(float %f) local_unnamed_addr #0 !dbg !25 {
+entry:
+  tail call void @llvm.dbg.value(metadata float %f, i64 0, metadata !36, metadata !22), !dbg !38
+  tail call void @llvm.dbg.value(metadata float 0.000000e+00, i64 0, metadata !36, metadata !23), !dbg !38
+  %retval.sroa.0.0.vec.insert = insertelement <2 x float> undef, float %f, i32 0, !dbg !39
+  %retval.sroa.0.4.vec.insert = insertelement <2 x float> %retval.sroa.0.0.vec.insert, float 0.000000e+00, i32 1, !dbg !39
+  ret <2 x float> %retval.sroa.0.4.vec.insert, !dbg !40
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1
+
+attributes #0 = { nounwind readnone ssp uwtable }
+attributes #1 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 4.0.0 (trunk 285655) (llvm/trunk 285654)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "stack-value-piece.c", directory: "/")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"PIC Level", i32 2}
+!6 = !{!"clang version 4.0.0 (trunk 285655) (llvm/trunk 285654)"}
+!7 = distinct !DISubprogram(name: "i", scope: !1, file: !1, line: 2, type: !8, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0)
+!8 = !DISubroutineType(types: !9)
+!9 = !{!10, !14}
+!10 = !DIDerivedType(tag: DW_TAG_typedef, name: "I", file: !1, line: 1, baseType: !11)
+!11 = distinct !DICompositeType(tag: DW_TAG_structure_type, file: !1, line: 1, size: 64, elements: !12)
+!12 = !{!13, !15}
+!13 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !11, file: !1, line: 1, baseType: !14, size: 32)
+!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!15 = !DIDerivedType(tag: DW_TAG_member, name: "b", scope: !11, file: !1, line: 1, baseType: !14, size: 32, offset: 32)
+!18 = !DILocalVariable(name: "r", scope: !7, file: !1, line: 3, type: !10)
+!19 = !DIExpression()
+!20 = !DILocation(line: 2, column: 9, scope: !7)
+!21 = !DILocation(line: 3, column: 5, scope: !7)
+!22 = !DIExpression(DW_OP_bit_piece, 0, 32)
+!23 = !DIExpression(DW_OP_bit_piece, 32, 32)
+!24 = !DILocation(line: 5, column: 1, scope: !7)
+!25 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 8, type: !26, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: true, unit: !0)
+!26 = !DISubroutineType(types: !27)
+!27 = !{!28, !32}
+!28 = !DIDerivedType(tag: DW_TAG_typedef, name: "F", file: !1, line: 7, baseType: !29)
+!29 = distinct !DICompositeType(tag: DW_TAG_structure_type, file: !1, line: 7, size: 64, elements: !30)
+!30 = !{!31, !33}
+!31 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !29, file: !1, line: 7, baseType: !32, size: 32)
+!32 = !DIBasicType(name: "float", size: 32, encoding: DW_ATE_float)
+!33 = !DIDerivedType(tag: DW_TAG_member, name: "b", scope: !29, file: !1, line: 7, baseType: !32, size: 32, offset: 32)
+!36 = !DILocalVariable(name: "r", scope: !25, file: !1, line: 9, type: !28)
+!37 = !DILocation(line: 8, column: 11, scope: !25)
+!38 = !DILocation(line: 9, column: 5, scope: !25)
+!39 = !DILocation(line: 10, column: 10, scope: !25)
+!40 = !DILocation(line: 11, column: 1, scope: !25)