--- |
; RUN: llc %s -march=x86-64 -run-pass=livedebugvalues -o - -force-instr-ref-livedebugvalues=1 -emulate-old-livedebugvalues=0 | FileCheck %s -implicit-check-not=DBG_VALUE
;; When using instruction referencing LiveDebugValues, when a register gets
;; clobbered, we should transfer variable locations to backup locations, if
;; one is available.
;; I've written this test in terms of DBG_VALUEs rather than DBG_INSTR_REFs
;; as this is purely a LiveDebugValues feature, and should work without the
;; need to use any other instructoin referencing work.
declare i32 @use() local_unnamed_addr;
define i32 @_Z8bb_to_bb() local_unnamed_addr !dbg !12 {
entry:
br label %bb1, !dbg !17
bb1:
br label %bb2, !dbg !17
bb2:
br label %bb3, !dbg !17
bb3:
br label %bb3, !dbg !17
bb4:
br label %bb3, !dbg !17
bb5:
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
stack:
- { id: 0, type: spill-slot, offset: -12, size: 4, alignment: 4 }
body: |
bb.0.entry:
$eax = MOV32ri 0, debug-location !17
$eax = COPY $ebx
DBG_VALUE $eax, $noreg, !16, !DIExpression(), debug-location !17
;; Over-write eax, we should recover its location as being in ebx.
$eax = MOV32ri 0, debug-location !17
; CHECK: DBG_VALUE $eax
; CHECK-NEXT: $eax = MOV32ri 0
; CHECK-NEXT: DBG_VALUE $ebx
;; The same should occur for spills.
$ebx = MOV32ri 2, debug-location !17
MOV32mr $rsp, 1, _, -12, _, killed $ebx :: (store 4 into %stack.0)
DBG_VALUE $ebx, $noreg, !16, !DIExpression(), debug-location !17
$ebx = MOV32ri 0, debug-location !17
; CHECK-NEXT: $ebx = MOV32ri 2
; CHECK-NEXT: MOV32mr $rsp
; CHECK-NEXT: DBG_VALUE $ebx
; CHECK-NEXT: $ebx = MOV32ri
; CHECK-NEXT: DBG_VALUE $rsp
;; Try re-loading the variable value from the stack; we shouldn't issue a
;; DBG_VALUE to follow it, the stack locations are usually longer lived and
;; this reduces location list entropy. Then, clobber the stack location,
;; and check that we can relocate the variable to being in the loaded
;; register.
$ebx = MOV32rm $rsp, 1, _, -12, _ :: (load 4 from %stack.0)
MOV32mr $rsp, 1, _, -12, _, killed $esi :: (store 4 into %stack.0)
; CHECK: $ebx = MOV32rm
; CHECK-NEXT: MOV32mr $rsp
; CHECK-NEXT: DBG_VALUE $ebx
;; Now test copies and register masks.
$eax = COPY $ebx
DBG_VALUE $ebx, $noreg, !16, !DIExpression(), debug-location !17
;; Overwrite ebx with a copy.
$ecx = MOV32ri 1, debug-location !17
$ebx = COPY $ecx
; CHECK: DBG_VALUE $ebx
; CHECK-NEXT: $ecx = MOV32ri
; CHECK-NEXT: $ebx = COPY
; CHECK-NEXT: DBG_VALUE $eax
;; Similarly, with a register mask
$ebx = COPY $eax
CALL64pcrel32 @use, csr_64, implicit $rsp, implicit $edi, implicit-def $rsp, debug-location !17
; CHECK-NEXT: $ebx = COPY $eax
; CHECK-NEXT: CALL64pcrel32
; CHECK-NEXT: DBG_VALUE $ebx
RET64 $eax, debug-location !17
...
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