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llvm-mirror/test/DebugInfo/X86/dbg-const.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

51 lines
2.1 KiB
LLVM

; RUN: llc < %s - | FileCheck %s
;
; FIXME: A potentially more interesting test case would be:
; %call = @bar()
; dbg.value j=0
; %call2 = @bar()
; dbg.value j=%call
;
; We cannot current handle the above sequence because codegenprepare
; hoists the second dbg.value above %call2, which then appears to
; conflict with j=0. It does this because SelectionDAG cannot handle
; global debug values.
target triple = "x86_64-apple-darwin10.0.0"
;CHECK: ## DW_OP_consts
;CHECK-NEXT: .byte 42
define i32 @foobar() nounwind readonly noinline ssp !dbg !0 {
entry:
tail call void @llvm.dbg.value(metadata i32 42, metadata !6, metadata !DIExpression()), !dbg !9
%call = tail call i32 @bar(), !dbg !11
tail call void @llvm.dbg.value(metadata i32 %call, metadata !6, metadata !DIExpression()), !dbg !11
%call2 = tail call i32 @bar(), !dbg !11
%add = add nsw i32 %call2, %call, !dbg !12
ret i32 %add, !dbg !10
}
declare void @llvm.dbg.value(metadata, metadata, metadata) nounwind readnone
declare i32 @bar() nounwind readnone
!llvm.dbg.cu = !{!2}
!llvm.module.flags = !{!17}
!0 = distinct !DISubprogram(name: "foobar", linkageName: "foobar", line: 12, isLocal: false, isDefinition: true, virtualIndex: 6, isOptimized: true, unit: !2, file: !15, scope: !1, type: !3, retainedNodes: !14)
!1 = !DIFile(filename: "mu.c", directory: "/private/tmp")
!2 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 2.9 (trunk 114183)", isOptimized: true, emissionKind: FullDebug, file: !15, enums: !16, retainedTypes: !16, imports: null)
!3 = !DISubroutineType(types: !4)
!4 = !{!5}
!5 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!6 = !DILocalVariable(name: "j", line: 15, scope: !7, file: !1, type: !5)
!7 = distinct !DILexicalBlock(line: 12, column: 52, file: !15, scope: !0)
!8 = !{i32 42}
!9 = !DILocation(line: 15, column: 12, scope: !7)
!10 = !DILocation(line: 23, column: 3, scope: !7)
!11 = !DILocation(line: 17, column: 3, scope: !7)
!12 = !DILocation(line: 18, column: 3, scope: !7)
!14 = !{!6}
!15 = !DIFile(filename: "mu.c", directory: "/private/tmp")
!16 = !{}
!17 = !{i32 1, !"Debug Info Version", i32 3}