llvm-mirror/test/DebugInfo/Generic/dead-argument-order.ll
Shiva Chen a2029fa58e [DebugInfo] Add DILabel metadata and intrinsic llvm.dbg.label.
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is

!DILabel(scope: !1, name: "foo", file: !2, line: 3)

We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is

llvm.dbg.label(metadata !1)

It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.

We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.

Differential Revision: https://reviews.llvm.org/D45024

Patch by Hsiangkai Wang.

llvm-svn: 331841
2018-05-09 02:40:45 +00:00

81 lines
3.5 KiB
LLVM

; REQUIRES: object-emission
; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -v -debug-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
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "i"
%struct.S = type { i32 }
; Function Attrs: nounwind readnone uwtable
define i32 @_Z8function1Si(i32 %s.coerce, i32 %i) #0 !dbg !9 {
entry:
tail call void @llvm.dbg.declare(metadata %struct.S* undef, metadata !14, metadata !DIExpression()), !dbg !20
tail call void @llvm.dbg.value(metadata i32 %i, metadata !15, metadata !DIExpression()), !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, metadata) #1
; Function Attrs: nounwind readnone
declare void @llvm.dbg.value(metadata, metadata, 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 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.5.0 ", isOptimized: true, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !3, globals: !2, imports: !2)
!1 = !DIFile(filename: "dead-argument-order.cpp", directory: "/tmp/dbginfo")
!2 = !{}
!3 = !{!4}
!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "S", line: 1, size: 32, align: 32, file: !1, elements: !5, identifier: "_ZTS1S")
!5 = !{!6}
!6 = !DIDerivedType(tag: DW_TAG_member, name: "i", line: 1, size: 32, align: 32, file: !1, scope: !4, baseType: !7)
!7 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!9 = distinct !DISubprogram(name: "function", linkageName: "_Z8function1Si", line: 2, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, unit: !0, scopeLine: 2, file: !1, scope: !10, type: !11, retainedNodes: !13)
!10 = !DIFile(filename: "dead-argument-order.cpp", directory: "/tmp/dbginfo")
!11 = !DISubroutineType(types: !12)
!12 = !{!7, !4, !7}
!13 = !{!14, !15}
!14 = !DILocalVariable(name: "s", line: 2, arg: 1, scope: !9, file: !10, type: !4)
!15 = !DILocalVariable(name: "i", line: 2, arg: 2, scope: !9, file: !10, type: !7)
!16 = !{i32 2, !"Dwarf Version", i32 4}
!17 = !{i32 2, !"Debug Info Version", i32 3}
!18 = !{!"clang version 3.5.0 "}
!19 = !{%struct.S* undef}
!20 = !DILocation(line: 2, scope: !9)