llvm-6502/test/DebugInfo/missing-abstract-variable.ll
David Blaikie e2cf6dc5c9 DebugInfo: Elide lexical scopes which only contain other (inline or lexical) scopes.
DW_TAG_lexical_scopes inform debuggers about the instruction range for
which a given variable (or imported declaration/module/etc) is valid. If
the scope doesn't itself contain any such entities, it's a waste of
space and should be omitted.

We were correctly doing this for entirely empty leaves, but not for
intermediate nodes.

Reduces total (not just debug sections) .o file size for a bootstrap
-gmlt LLVM by 22% and bootstrap -gmlt clang executable by 13%. The wins
for a full -g build will be less as a % (and in absolute terms), but
should still be substantial - with some of that win being fewer
relocations, thus more substantiall reducing link times than fewer bytes
alone would have.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216861 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-31 21:26:22 +00:00

183 lines
9.1 KiB
LLVM

; REQUIRES: object-emission
; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
; The formal parameter 'b' for Function 'x' when inlined within 'a' is lost on
; mips and powerpc64 (and on x86_64 at at least -O2). Presumably this is a
; SelectionDAG issue (do mips/powerpc64 use FastISel?).
; XFAIL: mips, powerpc64, s390x
; Build from the following source with clang -O2.
; The important details are that 'x's abstract definition is first built during
; the definition of 'b', where the parameter to 'x' is constant and so 'x's 's'
; variable is optimized away. No abstract definition DIE for 's' is constructed.
; Then, during 'a' emission, the abstract DbgVariable for 's' is created, but
; the abstract DIE isn't (since the abstract definition for 'b' is already
; built). This results in 's' inlined in 'a' being emitted with its name, line,
; file there, rather than referencing an abstract definition.
; extern int t;
;
; void f(int);
;
; inline void x(bool b) {
; if (b) {
; int s = t;
; f(s);
; }
; f(0);
; }
;
; void b() {
; x(false);
; }
;
; void a(bool u) {
; x(u);
; }
; CHECK: [[ABS_X:.*]]: DW_TAG_subprogram
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "x"
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: [[ABS_B:.*]]: DW_TAG_formal_parameter
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "b"
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_TAG_lexical_block
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: [[ABS_S:.*]]: DW_TAG_variable
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "s"
; CHECK: DW_TAG_subprogram
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "b"
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_TAG_inlined_subroutine
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_abstract_origin {{.*}} {[[ABS_X]]}
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_TAG_formal_parameter
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_abstract_origin {{.*}} {[[ABS_B]]}
; Notice 'x's local variable 's' is missing. Not necessarily a bug here,
; since it's been optimized entirely away and it should be described in
; abstract subprogram.
; CHECK-NOT: DW_TAG
; CHECK: NULL
; CHECK-NOT: DW_TAG
; CHECK: NULL
; CHECK: DW_TAG_subprogram
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "a"
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_TAG_formal_parameter
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_TAG_inlined_subroutine
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_abstract_origin {{.*}} {[[ABS_X]]}
; CHECK-NOT: {{DW_TAG|NULL}}
; FIXME: This formal parameter goes missing at least at -O2 (& on
; mips/powerpc), maybe before that. Perhaps SelectionDAG is to blame (and
; fastisel succeeds).
; CHECK: DW_TAG_formal_parameter
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_abstract_origin {{.*}} {[[ABS_B]]}
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_TAG_lexical_block
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_TAG_variable
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_abstract_origin {{.*}} {[[ABS_S]]}
@t = external global i32
; Function Attrs: uwtable
define void @_Z1bv() #0 {
entry:
tail call void @llvm.dbg.value(metadata !24, i64 0, metadata !25), !dbg !27
tail call void @_Z1fi(i32 0), !dbg !28
ret void, !dbg !29
}
; Function Attrs: uwtable
define void @_Z1ab(i1 zeroext %u) #0 {
entry:
tail call void @llvm.dbg.value(metadata !{i1 %u}, i64 0, metadata !13), !dbg !30
tail call void @llvm.dbg.value(metadata !{i1 %u}, i64 0, metadata !31), !dbg !33
br i1 %u, label %if.then.i, label %_Z1xb.exit, !dbg !34
if.then.i: ; preds = %entry
%0 = load i32* @t, align 4, !dbg !35, !tbaa !36
tail call void @llvm.dbg.value(metadata !{i32 %0}, i64 0, metadata !40), !dbg !35
tail call void @_Z1fi(i32 %0), !dbg !41
br label %_Z1xb.exit, !dbg !42
_Z1xb.exit: ; preds = %entry, %if.then.i
tail call void @_Z1fi(i32 0), !dbg !43
ret void, !dbg !44
}
declare void @_Z1fi(i32) #1
; Function Attrs: nounwind readnone
declare void @llvm.dbg.value(metadata, i64, metadata) #2
attributes #0 = { uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #2 = { nounwind readnone }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!21, !22}
!llvm.ident = !{!23}
!0 = metadata !{i32 786449, metadata !1, i32 4, metadata !"clang version 3.5.0 ", i1 true, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !"", i32 1} ; [ DW_TAG_compile_unit ] [/tmp/dbginfo/missing-abstract-variables.cc] [DW_LANG_C_plus_plus]
!1 = metadata !{metadata !"missing-abstract-variables.cc", metadata !"/tmp/dbginfo"}
!2 = metadata !{}
!3 = metadata !{metadata !4, metadata !8, metadata !14}
!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"b", metadata !"b", metadata !"_Z1bv", i32 13, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, void ()* @_Z1bv, null, null, metadata !2, i32 13} ; [ DW_TAG_subprogram ] [line 13] [def] [b]
!5 = metadata !{i32 786473, metadata !1} ; [ DW_TAG_file_type ] [/tmp/dbginfo/missing-abstract-variables.cc]
!6 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
!7 = metadata !{null}
!8 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"a", metadata !"a", metadata !"_Z1ab", i32 17, metadata !9, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, void (i1)* @_Z1ab, null, null, metadata !12, i32 17} ; [ DW_TAG_subprogram ] [line 17] [def] [a]
!9 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !10, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
!10 = metadata !{null, metadata !11}
!11 = metadata !{i32 786468, null, null, metadata !"bool", i32 0, i64 8, i64 8, i64 0, i32 0, i32 2} ; [ DW_TAG_base_type ] [bool] [line 0, size 8, align 8, offset 0, enc DW_ATE_boolean]
!12 = metadata !{metadata !13}
!13 = metadata !{i32 786689, metadata !8, metadata !"u", metadata !5, i32 16777233, metadata !11, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [u] [line 17]
!14 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"x", metadata !"x", metadata !"_Z1xb", i32 5, metadata !9, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, null, null, null, metadata !15, i32 5} ; [ DW_TAG_subprogram ] [line 5] [def] [x]
!15 = metadata !{metadata !16, metadata !17}
!16 = metadata !{i32 786689, metadata !14, metadata !"b", metadata !5, i32 16777221, metadata !11, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [b] [line 5]
!17 = metadata !{i32 786688, metadata !18, metadata !"s", metadata !5, i32 7, metadata !20, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [s] [line 7]
!18 = metadata !{i32 786443, metadata !1, metadata !19, i32 6, i32 0, i32 0, i32 1} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/missing-abstract-variables.cc]
!19 = metadata !{i32 786443, metadata !1, metadata !14, i32 6, i32 0, i32 0, i32 0} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/missing-abstract-variables.cc]
!20 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
!21 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
!22 = metadata !{i32 2, metadata !"Debug Info Version", i32 1}
!23 = metadata !{metadata !"clang version 3.5.0 "}
!24 = metadata !{i1 false}
!25 = metadata !{i32 786689, metadata !14, metadata !"b", metadata !5, i32 16777221, metadata !11, i32 0, metadata !26} ; [ DW_TAG_arg_variable ] [b] [line 5]
!26 = metadata !{i32 14, i32 0, metadata !4, null}
!27 = metadata !{i32 5, i32 0, metadata !14, metadata !26}
!28 = metadata !{i32 10, i32 0, metadata !14, metadata !26}
!29 = metadata !{i32 15, i32 0, metadata !4, null}
!30 = metadata !{i32 17, i32 0, metadata !8, null}
!31 = metadata !{i32 786689, metadata !14, metadata !"b", metadata !5, i32 16777221, metadata !11, i32 0, metadata !32} ; [ DW_TAG_arg_variable ] [b] [line 5]
!32 = metadata !{i32 18, i32 0, metadata !8, null}
!33 = metadata !{i32 5, i32 0, metadata !14, metadata !32}
!34 = metadata !{i32 6, i32 0, metadata !19, metadata !32}
!35 = metadata !{i32 7, i32 0, metadata !18, metadata !32}
!36 = metadata !{metadata !37, metadata !37, i64 0}
!37 = metadata !{metadata !"int", metadata !38, i64 0}
!38 = metadata !{metadata !"omnipotent char", metadata !39, i64 0}
!39 = metadata !{metadata !"Simple C/C++ TBAA"}
!40 = metadata !{i32 786688, metadata !18, metadata !"s", metadata !5, i32 7, metadata !20, i32 0, metadata !32} ; [ DW_TAG_auto_variable ] [s] [line 7]
!41 = metadata !{i32 8, i32 0, metadata !18, metadata !32} ; [ DW_TAG_imported_declaration ]
!42 = metadata !{i32 9, i32 0, metadata !18, metadata !32}
!43 = metadata !{i32 10, i32 0, metadata !14, metadata !32}
!44 = metadata !{i32 19, i32 0, metadata !8, null}