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llvm-project/llvm/test/DebugInfo/dead-argument-order.ll

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PR19388: DebugInfo: Emit dead arguments in their originally declared order. Unused arguments were not being added to the argument list, but instead treated as arbitrary scope variables. This meant they weren't carefully added in the original argument order. In this particular example, though, it turns out the argument is only /mostly/ unused (well, actually it's entirely used, but in a specific way). It's a struct that, due to ABI reasons, is decomposed into chunks (exactly one chunk, since it has one member) and then passed. Since only one of those chunks is used (SROA, etc, kill the original reconstitution code) we don't have a location to describe the whole variable. In this particular case, since the struct consists of just the one int, once we have partial location information, this should have a location that describes the entire variable (since the piece is the entirety of the object). And at some point we'll need to describe the location of even /entirely/ unused arguments so that they can at least be printed on function entry. llvm-svn: 210231
2014-06-05 08:51:35 +08:00
; REQUIRES: object-emission
; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
; Built from the following source with clang -O1
; struct S { int i; };
; int function(struct S s, int i) { return s.i + i; }
; Due to the X86_64 ABI, 's' is passed in registers and once optimized, the
; entirety of 's' is never reconstituted, since only the int is required, and
; thus the variable's location is unknown/dead to debug info.
; Future/current work should enable us to describe partial variables, which, in
; this case, happens to be the entire variable.
; CHECK: DW_TAG_subprogram
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "function"
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_TAG_formal_parameter
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "s"
; CHECK-NOT: DW_TAG
; FIXME: Even though 's' is never reconstituted into a struct, the one member
; variable is still live and used, and so we should be able to describe 's's
; location as the location of that int.
; CHECK-NOT: DW_AT_location
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_TAG_formal_parameter
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_location
DebugInfo: Following up to r209677, refactor local variable emission to delay the choice between emitting the definition attributes or using DW_AT_abstract_definition This doesn't fix the abstract variable handling yet, but it introduces a similar delay mechanism as was added for subprograms, causing DW_AT_location to be reordered to the beginning of the attribute list for local variables, and fixes all the test fallout for that. A subsequent commit will remove the abstract variable handling in DbgVariable and just do the abstract variable lookup at module end to ensure that abstract variables introduced after their concrete counterparts are appropriately referenced by the concrete variable. llvm-svn: 210943
2014-06-14 06:18:23 +08:00
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "i"
PR19388: DebugInfo: Emit dead arguments in their originally declared order. Unused arguments were not being added to the argument list, but instead treated as arbitrary scope variables. This meant they weren't carefully added in the original argument order. In this particular example, though, it turns out the argument is only /mostly/ unused (well, actually it's entirely used, but in a specific way). It's a struct that, due to ABI reasons, is decomposed into chunks (exactly one chunk, since it has one member) and then passed. Since only one of those chunks is used (SROA, etc, kill the original reconstitution code) we don't have a location to describe the whole variable. In this particular case, since the struct consists of just the one int, once we have partial location information, this should have a location that describes the entire variable (since the piece is the entirety of the object). And at some point we'll need to describe the location of even /entirely/ unused arguments so that they can at least be printed on function entry. llvm-svn: 210231
2014-06-05 08:51:35 +08:00
%struct.S = type { i32 }
; Function Attrs: nounwind readnone uwtable
define i32 @_Z8function1Si(i32 %s.coerce, i32 %i) #0 {
entry:
tail call void @llvm.dbg.declare(metadata !19, metadata !14), !dbg !20
tail call void @llvm.dbg.value(metadata !{i32 %i}, i64 0, metadata !15), !dbg !20
%add = add nsw i32 %i, %s.coerce, !dbg !20
ret i32 %add, !dbg !20
}
; Function Attrs: nounwind readnone
declare void @llvm.dbg.declare(metadata, metadata) #1
; Function Attrs: nounwind readnone
declare void @llvm.dbg.value(metadata, i64, metadata) #1
attributes #0 = { nounwind readnone 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 = { nounwind readnone }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!16, !17}
!llvm.ident = !{!18}
!0 = metadata !{i32 786449, metadata !1, i32 4, metadata !"clang version 3.5.0 ", i1 true, metadata !"", i32 0, metadata !2, metadata !3, metadata !8, metadata !2, metadata !2, metadata !"", i32 1} ; [ DW_TAG_compile_unit ] [/tmp/dbginfo/dead-argument-order.cpp] [DW_LANG_C_plus_plus]
!1 = metadata !{metadata !"dead-argument-order.cpp", metadata !"/tmp/dbginfo"}
!2 = metadata !{}
!3 = metadata !{metadata !4}
!4 = metadata !{i32 786451, metadata !1, null, metadata !"S", i32 1, i64 32, i64 32, i32 0, i32 0, null, metadata !5, i32 0, null, null, metadata !"_ZTS1S"} ; [ DW_TAG_structure_type ] [S] [line 1, size 32, align 32, offset 0] [def] [from ]
!5 = metadata !{metadata !6}
!6 = metadata !{i32 786445, metadata !1, metadata !"_ZTS1S", metadata !"i", i32 1, i64 32, i64 32, i64 0, i32 0, metadata !7} ; [ DW_TAG_member ] [i] [line 1, size 32, align 32, offset 0] [from int]
!7 = 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]
!8 = metadata !{metadata !9}
!9 = metadata !{i32 786478, metadata !1, metadata !10, metadata !"function", metadata !"function", metadata !"_Z8function1Si", i32 2, metadata !11, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, i32 (i32, i32)* @_Z8function1Si, null, null, metadata !13, i32 2} ; [ DW_TAG_subprogram ] [line 2] [def] [function]
!10 = metadata !{i32 786473, metadata !1} ; [ DW_TAG_file_type ] [/tmp/dbginfo/dead-argument-order.cpp]
!11 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !12, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
!12 = metadata !{metadata !7, metadata !4, metadata !7}
!13 = metadata !{metadata !14, metadata !15}
!14 = metadata !{i32 786689, metadata !9, metadata !"s", metadata !10, i32 16777218, metadata !"_ZTS1S", i32 0, i32 0} ; [ DW_TAG_arg_variable ] [s] [line 2]
!15 = metadata !{i32 786689, metadata !9, metadata !"i", metadata !10, i32 33554434, metadata !7, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [i] [line 2]
!16 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
!17 = metadata !{i32 2, metadata !"Debug Info Version", i32 1}
!18 = metadata !{metadata !"clang version 3.5.0 "}
!19 = metadata !{%struct.S* undef}
!20 = metadata !{i32 2, i32 0, metadata !9, null}