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llvm-mirror/test/DebugInfo/X86/formal_parameter.ll
Jeremy Morse b2c5377fb4 [DebugInfo] Use zero linenos for debug intrinsics when promoting dbg.declare
In certain circumstances, optimizations pick line numbers from debug
intrinsic instructions as the new location for altered instructions. This
is problematic because the line number of a debugging intrinsic is
meaningless (it doesn't produce any machine instruction), only the scope
information is valid. The result can be the line number of a variable
declaration "leaking" into real code from debugging intrinsics, making the
line table un-necessarily jumpy, and potentially different with / without
variable locations.

Fix this by using zero line numbers when promoting dbg.declare intrinsics
into dbg.values: this is safe for debug intrinsics as their line numbers
are meaningless, and reduces the scope for damage / misleading stepping
when optimizations pick locations from the wrong place.

Differential Revision: https://reviews.llvm.org/D59272

llvm-svn: 360415
2019-05-10 10:03:41 +00:00

87 lines
3.3 KiB
LLVM

; ModuleID = 'formal_parameter.c'
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.9.0"
;
; From (clang -g -c -O1):
;
; int lookup(int* map);
; int verify(int val);
; void foo(int map)
; {
; lookup(&map);
; if (!verify(map)) { }
; }
;
; RUN: opt %s -O2 -S -o %t
; RUN: cat %t | FileCheck --check-prefix=LOWERING %s
; RUN: llc -filetype=obj %t -o - | llvm-dwarfdump -debug-info - | FileCheck %s
; Test that we only emit only one DW_AT_formal_parameter "map" for this function.
; rdar://problem/14874886
;
; CHECK: DW_TAG_formal_parameter
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}}map
; CHECK-NOT: DW_AT_name {{.*}}map
; Function Attrs: nounwind ssp uwtable
define void @foo(i32 %map) #0 !dbg !4 {
entry:
%map.addr = alloca i32, align 4
store i32 %map, i32* %map.addr, align 4, !tbaa !15
call void @llvm.dbg.declare(metadata i32* %map.addr, metadata !10, metadata !DIExpression()), !dbg !14
%call = call i32 (i32*, ...) bitcast (i32 (...)* @lookup to i32 (i32*, ...)*)(i32* %map.addr) #3, !dbg !19
; Ensure that all dbg intrinsics have the same scope after
; LowerDbgDeclare is finished with them.
;
; LOWERING: call void @llvm.dbg.value{{.*}}, !dbg ![[LOC:.*]]
; LOWERING: call void @llvm.dbg.value{{.*}}, !dbg ![[LOC]]
; LOWERING: call void @llvm.dbg.value{{.*}}, !dbg ![[LOC]]
%0 = load i32, i32* %map.addr, align 4, !dbg !20, !tbaa !15
%call1 = call i32 (i32, ...) bitcast (i32 (...)* @verify to i32 (i32, ...)*)(i32 %0) #3, !dbg !20
ret void, !dbg !22
}
; LOWERING: ![[SCOPE:[0-9]+]] = distinct !DISubprogram(name: "foo",
; LOWERING: ![[LOC]] = !DILocation(line: 0, scope: ![[SCOPE]]
; Function Attrs: nounwind readnone
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
declare i32 @lookup(...)
declare i32 @verify(...)
; Function Attrs: nounwind readnone
declare void @llvm.dbg.value(metadata, metadata, metadata) #1
attributes #0 = { nounwind ssp uwtable }
attributes #1 = { nounwind readnone }
attributes #3 = { nounwind }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!11, !12}
!llvm.ident = !{!13}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.5.0 ", isOptimized: true, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
!1 = !DIFile(filename: "formal_parameter.c", directory: "")
!2 = !{}
!4 = distinct !DISubprogram(name: "foo", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, unit: !0, scopeLine: 2, file: !1, scope: !5, type: !6, retainedNodes: !9)
!5 = !DIFile(filename: "formal_parameter.c", directory: "")
!6 = !DISubroutineType(types: !7)
!7 = !{null, !8}
!8 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!9 = !{!10}
!10 = !DILocalVariable(name: "map", line: 1, arg: 1, scope: !4, file: !5, type: !8)
!11 = !{i32 2, !"Dwarf Version", i32 2}
!12 = !{i32 1, !"Debug Info Version", i32 3}
!13 = !{!"clang version 3.5.0 "}
!14 = !DILocation(line: 1, scope: !4)
!15 = !{!16, !16, i64 0}
!16 = !{!"int", !17, i64 0}
!17 = !{!"omnipotent char", !18, i64 0}
!18 = !{!"Simple C/C++ TBAA"}
!19 = !DILocation(line: 3, scope: !4)
!20 = !DILocation(line: 4, scope: !21)
!21 = distinct !DILexicalBlock(line: 4, column: 0, file: !1, scope: !4)
!22 = !DILocation(line: 5, scope: !4)