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llvm-mirror/test/DebugInfo/X86/dbg-value-g-gmlt.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

101 lines
4.2 KiB
LLVM

; RUN: llc < %s -filetype=obj | llvm-dwarfdump -v - --debug-info | FileCheck %s
;
; IR module created as follows:
; clang -emit-llvm -S -O2 foo.cpp -o foo.ll -g
; clang -emit-llvm -S -O2 bar.cpp -o bar.ll -gmlt
; llvm-link foo.ll bar.ll -S -o linked.ll
; opt -std-link-opts linked.ll -S -o opt.ll
; --- foo.cpp ---
; void f();
; void foo(int param) {
; if (param) f();
; }
; --- bar.cpp ---
; void foo(int);
; void bar() {
; foo(0);
; }
; ---
; The point is that bar() is compiled -gmlt and calls foo() with a constant 0.
; foo() is compiled -g and gets inlined into bar(); foo's body is then
; optimized away, leaving only a dbg.value call describing the inlined copy
; of 'param', which should be benign.
; That is, the compile-unit for bar.cpp should have nothing in it.
; PR31437.
; foo.cpp's unit comes first; skip past it, second unit should be empty.
; CHECK: DW_TAG_compile_unit
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_AT_name {{.*}} "foo.cpp"
; CHECK: DW_TAG_compile_unit
; CHECK-NOT: DW_TAG
; ModuleID = 'linked.ll'
source_filename = "llvm-link"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: uwtable
define void @_Z3fooi(i32 %param) local_unnamed_addr #0 !dbg !8 {
entry:
tail call void @llvm.dbg.value(metadata i32 %param, metadata !13, metadata !14), !dbg !15
%tobool = icmp eq i32 %param, 0, !dbg !16
br i1 %tobool, label %if.end, label %if.then, !dbg !18
if.then: ; preds = %entry
tail call void @_Z1fv(), !dbg !19
br label %if.end, !dbg !19
if.end: ; preds = %if.then, %entry
ret void, !dbg !21
}
; Function Attrs: nounwind readnone
declare void @llvm.dbg.value(metadata, metadata, metadata) #1
declare void @_Z1fv() local_unnamed_addr #2
; Function Attrs: nounwind readnone uwtable
define void @_Z3barv() local_unnamed_addr #3 !dbg !22 {
entry:
tail call void @llvm.dbg.value(metadata i32 0, metadata !13, metadata !14), !dbg !24
ret void, !dbg !26
}
attributes #0 = { uwtable }
attributes #1 = { nounwind readnone }
attributes #2 = { nounwind }
attributes #3 = { nounwind readnone uwtable }
!llvm.dbg.cu = !{!0, !3}
!llvm.ident = !{!5, !5}
!llvm.module.flags = !{!6, !7}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 5.0.0 (trunk 293745)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
!1 = !DIFile(filename: "foo.cpp", directory: "/home/probinson/projects/scratch/pr31437")
!2 = !{}
!3 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !4, producer: "clang version 5.0.0 (trunk 293745)", isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2)
!4 = !DIFile(filename: "bar.cpp", directory: "/home/probinson/projects/scratch/pr31437")
!5 = !{!"clang version 5.0.0 (trunk 293745)"}
!6 = !{i32 2, !"Dwarf Version", i32 4}
!7 = !{i32 2, !"Debug Info Version", i32 3}
!8 = distinct !DISubprogram(name: "foo", linkageName: "_Z3fooi", scope: !1, file: !1, line: 2, type: !9, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !12)
!9 = !DISubroutineType(types: !10)
!10 = !{null, !11}
!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!12 = !{!13}
!13 = !DILocalVariable(name: "param", arg: 1, scope: !8, file: !1, line: 2, type: !11)
!14 = !DIExpression()
!15 = !DILocation(line: 2, column: 14, scope: !8)
!16 = !DILocation(line: 3, column: 7, scope: !17)
!17 = distinct !DILexicalBlock(scope: !8, file: !1, line: 3, column: 7)
!18 = !DILocation(line: 3, column: 7, scope: !8)
!19 = !DILocation(line: 3, column: 14, scope: !20)
!20 = !DILexicalBlockFile(scope: !17, file: !1, discriminator: 1)
!21 = !DILocation(line: 4, column: 1, scope: !8)
!22 = distinct !DISubprogram(name: "bar", scope: !4, file: !4, line: 2, type: !23, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !3, retainedNodes: !2)
!23 = !DISubroutineType(types: !2)
!24 = !DILocation(line: 2, column: 14, scope: !8, inlinedAt: !25)
!25 = distinct !DILocation(line: 3, column: 3, scope: !22)
!26 = !DILocation(line: 4, column: 1, scope: !22)