DebugInfo: Include the decl_line/decl_file in subprogram definitions if they differ from those in the declaration

This is handy for some AutoFDO stuff, and seems like a minor improvement
to correctness (otherwise a debug info consumer might think the decl
line/file of the def was the same as that of the declaration - though
what a consumer might use that for, I'm not sure - maybe "list <func>"
would've misbehaved with the old behavior?) and at a minor cost (in my
experiment, with fission, without type units, without compression, 0.01%
growth in debug info in the executable/objects, 0.02% growth in the .dwo
files).

llvm-svn: 249487

1 files changed, 95 insertions, 0 deletions

diff --git a/llvm/test/DebugInfo/Generic/def-line.ll b/llvm/test/DebugInfo/Generic/def-line.ll
new file mode 100644
index 00000000000..066b360589b
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/def-line.ll
@@ -0,0 +1,95 @@
+; REQUIRES: object-emission
+
+; RUN: %llc_dwarf < %s -filetype=obj | llvm-dwarfdump -debug-dump=info - | FileCheck %s
+
+; Given the following source, ensure that the decl_line/file is correctly
+; emitted and omitted on definitions if it mismatches/matches the declaration
+
+; struct foo {
+;   static void f1() {
+;   }
+;   static void f2();
+;   static void f3();
+; };
+; void foo::f2() {
+;   f1(); // just to ensure f1 is emitted
+; }
+; #line 1 "bar.cpp"
+; void foo::f3() {
+; }
+
+; Skip the declarations
+; CHECK: DW_TAG_subprogram
+; CHECK: DW_TAG_subprogram
+; CHECK: DW_TAG_subprogram
+
+; CHECK: DW_TAG_subprogram
+; CHECK-NOT: {{DW_TAG|NULL|DW_AT_decl_file}}
+; CHECK:   DW_AT_decl_line {{.*}}7
+; CHECK-NOT: {{DW_TAG|NULL|DW_AT_decl_file}}
+; CHECK:   DW_AT_specification {{.*}}f2
+; CHECK-NOT: {{DW_TAG|NULL|DW_AT_decl_file}}
+
+; CHECK: DW_TAG_subprogram
+; CHECK-NOT: {{DW_TAG|NULL|DW_AT_decl_line|DW_AT_decl_file}}
+; CHECK:   DW_AT_specification {{.*}}f1
+
+; CHECK: DW_TAG_subprogram
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:   DW_AT_decl_file {{.*}}bar.cpp
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:   DW_AT_decl_line {{.*}}1
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:   DW_AT_specification {{.*}}f3
+
+$_ZN3foo2f1Ev = comdat any
+
+; Function Attrs: uwtable
+define void @_ZN3foo2f2Ev() #0 align 2 {
+entry:
+  call void @_ZN3foo2f1Ev(), !dbg !19
+  ret void, !dbg !20
+}
+
+; Function Attrs: nounwind uwtable
+define linkonce_odr void @_ZN3foo2f1Ev() #1 comdat align 2 {
+entry:
+  ret void, !dbg !21
+}
+
+; Function Attrs: nounwind uwtable
+define void @_ZN3foo2f3Ev() #1 align 2 {
+entry:
+  ret void, !dbg !22
+}
+
+attributes #0 = { uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!16, !17}
+!llvm.ident = !{!18}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 249440) (llvm/trunk 249465)", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2, retainedTypes: !3, subprograms: !11)
+!1 = !DIFile(filename: "def-line.cpp", directory: "/tmp/dbginfo")
+!2 = !{}
+!3 = !{!4}
+!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "foo", file: !1, line: 1, size: 8, align: 8, elements: !5, identifier: "_ZTS3foo")
+!5 = !{!6, !9, !10}
+!6 = !DISubprogram(name: "f1", linkageName: "_ZN3foo2f1Ev", scope: !"_ZTS3foo", file: !1, line: 2, type: !7, isLocal: false, isDefinition: false, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false)
+!7 = !DISubroutineType(types: !8)
+!8 = !{null}
+!9 = !DISubprogram(name: "f2", linkageName: "_ZN3foo2f2Ev", scope: !"_ZTS3foo", file: !1, line: 4, type: !7, isLocal: false, isDefinition: false, scopeLine: 4, flags: DIFlagPrototyped, isOptimized: false)
+!10 = !DISubprogram(name: "f3", linkageName: "_ZN3foo2f3Ev", scope: !"_ZTS3foo", file: !1, line: 5, type: !7, isLocal: false, isDefinition: false, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: false)
+!11 = !{!12, !13, !15}
+!12 = distinct !DISubprogram(name: "f2", linkageName: "_ZN3foo2f2Ev", scope: !"_ZTS3foo", file: !1, line: 7, type: !7, isLocal: false, isDefinition: true, scopeLine: 7, flags: DIFlagPrototyped, isOptimized: false, function: void ()* @_ZN3foo2f2Ev, declaration: !9, variables: !2)
+!13 = distinct !DISubprogram(name: "f3", linkageName: "_ZN3foo2f3Ev", scope: !"_ZTS3foo", file: !14, line: 1, type: !7, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, function: void ()* @_ZN3foo2f3Ev, declaration: !10, variables: !2)
+!14 = !DIFile(filename: "bar.cpp", directory: "/tmp/dbginfo")
+!15 = distinct !DISubprogram(name: "f1", linkageName: "_ZN3foo2f1Ev", scope: !"_ZTS3foo", file: !1, line: 2, type: !7, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false, function: void ()* @_ZN3foo2f1Ev, declaration: !6, variables: !2)
+!16 = !{i32 2, !"Dwarf Version", i32 4}
+!17 = !{i32 2, !"Debug Info Version", i32 3}
+!18 = !{!"clang version 3.8.0 (trunk 249440) (llvm/trunk 249465)"}
+!19 = !DILocation(line: 8, column: 3, scope: !12)
+!20 = !DILocation(line: 9, column: 1, scope: !12)
+!21 = !DILocation(line: 3, column: 3, scope: !15)
+!22 = !DILocation(line: 2, column: 1, scope: !13)