--- |
; RUN: llc %s -march=x86-64 -run-pass=livedebugvalues -o - -experimental-debug-variable-locations | FileCheck %s -implicit-check-not=DBG_VALUE
define i32 @_Z8bb_to_bb() local_unnamed_addr !dbg !12 {
entry:
ret i32 0, !dbg !17
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!7, !8, !9, !10}
!llvm.ident = !{!11}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 10.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3, debugInfoForProfiling: true, nameTableKind: None)
!1 = !DIFile(filename: "main.cpp", directory: "F:\")
!2 = !{}
!3 = !{!4}
!4 = !DIGlobalVariableExpression(var: !5, expr: !DIExpression())
!5 = distinct !DIGlobalVariable(name: "start", scope: !0, file: !1, line: 4, type: !6, isLocal: false, isDefinition: true)
!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!7 = !{i32 2, !"Dwarf Version", i32 4}
!8 = !{i32 2, !"Debug Info Version", i32 3}
!9 = !{i32 1, !"wchar_size", i32 2}
!10 = !{i32 7, !"PIC Level", i32 2}
!11 = !{!"clang version 10.0.0"}
!12 = distinct !DISubprogram(name: "bb_to_bb", linkageName: "bb_to_bb", scope: !1, file: !1, line: 6, type: !13, scopeLine: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !15)
!13 = !DISubroutineType(types: !14)
!14 = !{!6, !6}
!15 = !{!16}
!16 = !DILocalVariable(name: "myVar", scope: !12, file: !1, line: 7, type: !6)
!17 = !DILocation(line: 10, scope: !12)
...
---
name: _Z8bb_to_bb
debugInstrRef: true
debugValueSubstitutions:
- { srcinst: 4, srcop: 0, dstinst: 3, dstop: 0, subreg: 0 }
body: |
bb.0.entry:
$rax = MOV64ri 1, debug-instr-number 1, debug-location !17
; This debug instruction should identify the value as being in $rax.
DBG_INSTR_REF !16, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(1, 0), debug-location !17
; CHECK: DBG_VALUE_LIST {{.+}}, $rax
$rbx = COPY killed $rax, debug-location !17
$rax = MOV64ri 1, debug-location !17
; CHECK: DBG_VALUE_LIST {{.+}}, $rbx
DBG_INSTR_REF !16, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(2, 0), debug-location !17
; No instruction is labelled with the number "2". This should produce an
; empty variable location.
; CHECK: DBG_VALUE_LIST {{.+}}, $noreg
$rbx = MOV64ri 1, debug-instr-number 3, debug-location !17
JMP_1 %bb.1
; CHECK-LABEL: bb.1:
bb.1:
DBG_INSTR_REF !16, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(3, 0), debug-location !17
; This refers to a value def'd in a parent block -- but it should be
; tracked into this block.
; CHECK: DBG_VALUE_LIST {{.+}}, $rbx
JMP_1 %bb.2
; CHECK-LABEL: bb.2:
bb.2:
; Just like any other variable location, live-ins should be created for
; any successor blocks.
; CHECK: DBG_VALUE_LIST {{.+}}, $rbx
DBG_INSTR_REF !16, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(5, 0), debug-location !17
; This is a debug use-before-def: the value appears a few instructions
; later. Any earlier value should be terminated here, _and_ we should
; emit a DBG_VALUE when the value becomes available.
; CHECK: DBG_VALUE_LIST {{.+}}, $noreg
$rax = MOV64ri 1, debug-location !17
$rax = MOV64ri 1, debug-location !17
$rcx = MOV64ri 1, debug-instr-number 5, debug-location !17
; CHECK: DBG_VALUE_LIST {{.+}}, $rcx
$rax = MOV64ri 1, debug-location !17
DBG_INSTR_REF !16, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(6, 0), debug-location !17
; Another debug use-before-def, but across block boundaries.
; CHECK: DBG_VALUE_LIST {{.+}}, $noreg
JMP_1 %bb.3
; CHECK-LABEL: bb.3:
bb.3:
$rax = MOV64ri 1, debug-location !17
$rdx = MOV64ri 1, debug-instr-number 6, debug-location !17
; CHECK: DBG_VALUE_LIST {{.+}}, $rdx
; Terminate variable location for next few blocks,
DBG_VALUE $noreg, $noreg, !16, !DIExpression(), debug-location !17
; CHECK: DBG_VALUE $noreg, $noreg
JMP_1 %bb.4
bb.4:
; The next three blocks form a debug use-before-def modelling a scenario
; where an instruction is sunk (debug inst in bb5, value in bb6). However,
; because a different path joins bb.6, we should _not_ add any DBG_VALUE.
; A different variable value may enter the block via the other path.
$rdx = MOV64ri 1, implicit-def $eflags, debug-location !17
JCC_1 %bb.6, 4, implicit $eflags, debug-location !17
bb.5:
DBG_INSTR_REF !16, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(7, 0), debug-location !17
; CHECK: DBG_VALUE_LIST {{.+}}, $noreg
JMP_1 %bb.6, debug-location !17
bb.6:
$rsi = MOV64ri 1, debug-instr-number 7, debug-location !17
JMP_1 %bb.7, debug-location !17
; A use-before-def shouldn't pass another definition of the variable location
; or value.
bb.7:
DBG_INSTR_REF !16, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(8, 0), debug-location !17
; CHECK: DBG_VALUE_LIST {{.+}}, $noreg
DBG_VALUE $rax, $noreg, !16, !DIExpression(), debug-location !17
; CHECK: DBG_VALUE $rax, $noreg,
$rdi = MOV64ri 1, debug-instr-number 8, debug-location !17
; Loops: use-before-defs should be live-through loops, assuming that nothing
; in that loop modifies the variable location.
bb.8:
DBG_INSTR_REF !16, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(9, 0), debug-location !17
; CHECK: DBG_VALUE_LIST {{.+}}, $noreg
JCC_1 %bb.8, 4, implicit $eflags
bb.9:
$rax = MOV64ri 11, debug-instr-number 9, debug-location !17
; CHECK: DBG_VALUE_LIST {{.+}}, $rax
; Likewise, use-before-defs where anything changes the variable location
; or value in the loop, should be discarded.
bb.10:
; live-in,
; CHECK: DBG_VALUE_LIST {{.+}}, $rax
DBG_INSTR_REF !16, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(10, 0), debug-location !17
; CHECK: DBG_VALUE_LIST {{.+}}, $noreg
bb.11:
$rbx = MOV64ri 1, debug-location !17
bb.12:
DBG_INSTR_REF !16, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(9, 0), debug-location !17
; This still has a value in $rax,
; CHECK: DBG_VALUE_LIST {{.+}}, $rax
JCC_1 %bb.11, 4, implicit $eflags
bb.13:
; Live in,
; CHECK: DBG_VALUE_LIST {{.+}}, $rax
$rbx = MOV64ri 11, debug-instr-number 10, debug-location !17
; This is instruction 10 referred to in bb.10. However, as the variable
; location/value has been modified in the meantime, no DBG_VALUE should be
; generated here.
RET64 $eax, debug-location !17
...
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