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llvm-mirror/test/DebugInfo/Generic/dbg-value-lower-linenos.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

114 lines
4.6 KiB
LLVM

; RUN: opt < %s -S -mem2reg -instcombine | FileCheck %s
; The '%bar' alloca will be promoted to an SSA register by mem2reg: test that
; zero line number are assigned to the dbg.value intrinsics that are inserted
; to represent changes in variable value. No machine instructions are
; generated from these dbg.values so their lines are irrelevant, only the
; scope and inlining information must be correct.
; In the second function here, LowerDbgDeclare will promote various variable
; accesses of a dbg.declare'd alloca into dbg.values. Check that their line
; numbers are sane too. (IR copied from DebugInfo/X86/formal_parameter.ll).
; CHECK-LABEL: define i32 @foo
; CHECK-LABEL: bb1:
; CHECK-NEXT: %bar.0 = phi i32
; CHECK-NEXT: dbg.value(metadata i32 %bar.0,{{.*}}), !dbg ![[UNKNOWN:[0-9]+]]
; CHECK-NEXT: %totest = load
; CHECK-NEXT: %add = add i32 %bar.0
; CHECK-NEXT: dbg.value(metadata i32 %add, {{.*}}), !dbg ![[UNKNOWN]]
; CHECK-NEXT: %cond = icmp ult
; CHECK-NEXT: br i1 %cond, label %bb1, label %bb2
;
; CHECK-LABEL: bb2:
; CHECK-NEXT: %toret = add i32 %bar.0, 3
; CHECK-NEXT: dbg.value(metadata i32 %toret, {{.*}}), !dbg ![[UNKNOWN]]
; CHECK-NEXT: ret i32 %toret
define i32 @foo(i32 *%bees, i32 *%output) {
entry:
%bar = alloca i32
call void @llvm.dbg.declare(metadata i32 *%bar, metadata !7, metadata !DIExpression()), !dbg !6
store i32 0, i32 *%bar
br label %bb1, !dbg !6
bb1:
%totest = load i32, i32 *%bees, !dbg !8
%load1 = load i32, i32 *%bar, !dbg !9
%add = add i32 %load1, 1, !dbg !10
store i32 %add, i32 *%bar, !dbg !11
%toret = add i32 %add, 2, !dbg !12
%cond = icmp ult i32 %totest, %load1, !dbg !13
br i1 %cond, label %bb1, label %bb2, !dbg !14
bb2:
store i32 %toret, i32 *%bar, !dbg !16
ret i32 %toret
}
; In the following, the dbg.value created for the store should get the stores
; line number, the other dbg.values should be unknown.
; CHECK-LABEL: define void @bar
;
; CHECK: dbg.value(metadata i32 %map, metadata ![[MAPVAR:[0-9]+]],{{.*}}),
; CHECK-SAME: !dbg ![[UNKNOWN2:[0-9]+]]
; CHECK-NEXT: store
; CHECK-NEXT: dbg.value(metadata i32* %map.addr, metadata ![[MAPVAR]],
; CHECK-SAME: metadata !DIExpression(DW_OP_deref)),
; CHECK-SAME: !dbg ![[UNKNOWN2]]
; CHECK-NEXT: call
; CHECK-NEXT: load
; CHECK-NEXT: dbg.value(metadata i32 %{{[0-9]+}}, metadata ![[MAPVAR]],
; CHECK-SAME: !dbg ![[UNKNOWN2]]
define void @bar(i32 %map) !dbg !20 {
entry:
%map.addr = alloca i32, align 4
store i32 %map, i32* %map.addr, align 4, !dbg !27
call void @llvm.dbg.declare(metadata i32* %map.addr, metadata !21, metadata !DIExpression()), !dbg !22
%call = call i32 (i32*, ...) bitcast (i32 (...)* @lookup to i32 (i32*, ...)*)(i32* %map.addr), !dbg !23
%0 = load i32, i32* %map.addr, align 4, !dbg !24
%call1 = call i32 (i32, ...) bitcast (i32 (...)* @verify to i32 (i32, ...)*)(i32 %0), !dbg !25
ret void, !dbg !26
}
declare void @llvm.dbg.value(metadata, metadata, metadata)
declare void @llvm.dbg.declare(metadata, metadata, metadata)
declare i32 @verify(...)
declare i32 @lookup(...)
; CHECK: ![[SUBPROG:[0-9]+]] = distinct !DISubprogram(name: "nope",
; CHECK: ![[UNKNOWN]] = !DILocation(line: 0, scope: ![[SUBPROG]])
; CHECK: ![[SUBPROG2:[0-9]+]] = distinct !DISubprogram(name: "thin",
; CHECK: ![[MAPVAR]] = !DILocalVariable(name: "floogie",
; CHECK: ![[UNKNOWN2]] = !DILocation(line: 0
!llvm.module.flags = !{!4}
!llvm.dbg.cu = !{!2}
!1 = !DILocalVariable(name: "bees", scope: !5, type: null)
!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "beards", isOptimized: true, runtimeVersion: 4, emissionKind: FullDebug)
!3 = !DIFile(filename: "bees.cpp", directory: "")
!4 = !{i32 2, !"Debug Info Version", i32 3}
!5 = distinct !DISubprogram(name: "nope", scope: !3, file: !3, line: 1, unit: !2)
!6 = !DILocation(line: 1, scope: !5)
!7 = !DILocalVariable(name: "flannel", scope: !5, type: null)
!8 = !DILocation(line: 2, scope: !5)
!9 = !DILocation(line: 3, scope: !5)
!10 = !DILocation(line: 4, scope: !5)
!11 = !DILocation(line: 5, scope: !5)
!12 = !DILocation(line: 6, scope: !5)
!13 = !DILocation(line: 7, scope: !5)
!14 = !DILocation(line: 8, scope: !5)
!15 = distinct !DISubprogram(name: "wat", scope: !2, file: !3, line: 10, unit: !2)
!16 = !DILocation(line: 9, scope: !15, inlinedAt: !14)
!20 = distinct !DISubprogram(name: "thin", scope: !3, file: !3, line: 20, unit: !2)
!21 = !DILocalVariable(name: "floogie", scope: !20, type: null)
!22 = !DILocation(line: 21, scope: !20)
!23 = !DILocation(line: 22, scope: !20)
!24 = !DILocation(line: 23, scope: !20)
!25 = !DILocation(line: 24, scope: !20)
!26 = !DILocation(line: 25, scope: !20)
!27 = !DILocation(line: 20, scope: !20)