test/DebugInfo/MIR/X86/live-debug-values-restore-collide.mir

# RUN: llc %s -o - -run-pass=livedebugvalues -mtriple=x86_64-unknown-unknown | FileCheck %s
#
# This is a regression test for register/stack variable locations being
# interpreted as each other. We place a variable location on the stack, based
# on $rsp. We later make a memory load from $rsp. On faulty versions of LLVM
# this gets interpreted as a stack restore of the spilt value (it's not).
#
# Test that LiveDebugValues does not create any new variable locations.
#
# CHECK-LABEL: name: baaar
# CHECK-LABEL: bb.0.entry:
# CHECK:       DBG_VALUE $r9d, $noreg, !{{[0-9]*}}, !DIExpression()
# CHECK:       DBG_VALUE $rsp, 0, !{{[0-9]*}}, !DIExpression(DW_OP_plus_uconst, 16)
# CHECK-NOT:   DBG_VALUE
--- |
  target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
  target triple = "x86_64-unknown-linux-gnu"
  
  define void @baaar() !dbg !4 {
  entry:
    ret void
  }
  
  !llvm.module.flags = !{!0, !1}
  !llvm.dbg.cu = !{!2}
  
  !0 = !{i32 2, !"Debug Info Version", i32 3}
  !1 = !{i32 2, !"Dwarf Version", i32 4}
  !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
  !3 = !DIFile(filename: "sheep.cpp", directory: ".")
  !4 = distinct !DISubprogram(name: "baaar", scope: !3, file: !3, line: 1, type: !5, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !8)
  !5 = !DISubroutineType(types: !6)
  !6 = !{!7}
  !7 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
  !8 = !{!9}
  !9 = !DILocalVariable(name: "moo", scope: !4, file: !3, line: 1, type: !7)
  !10 = !DILocation(line: 1, scope: !4)

...
---
name:            baaar
alignment:       16
tracksRegLiveness: true
liveins:
  - { reg: '$rdi', virtual-reg: '' }
  - { reg: '$rsi', virtual-reg: '' }
  - { reg: '$rdx', virtual-reg: '' }
  - { reg: '$rcx', virtual-reg: '' }
  - { reg: '$r8', virtual-reg: '' }
  - { reg: '$r9d', virtual-reg: '' }
frameInfo:
  stackSize:       24
  offsetAdjustment: -24
  maxAlignment:    8
  adjustsStack:    true
  hasCalls:        true
fixedStack:
stack:
  - { id: 0, name: '', type: spill-slot, offset: -16, size: 8, alignment: 8, 
      stack-id: default, callee-saved-register: '', callee-saved-restored: true, 
      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
  - { id: 1, name: '', type: spill-slot, offset: -32, size: 8, alignment: 8, 
      stack-id: default, callee-saved-register: '', callee-saved-restored: true, 
      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
body:             |
  bb.0.entry:
    liveins: $rcx, $rdi, $rdx, $rsi, $r8, $r9d, $rbp, $r15, $r14, $r13, $r12, $rbx
  
    ; Setup
    DBG_VALUE $r9d, $noreg, !9, !DIExpression(), debug-location !10
    $rsp = frame-setup SUB64ri8 $rsp, 24, implicit-def dead $eflags

    ; Spill
    MOV32mr $rsp, 1, $noreg, 16, $noreg, $r9d :: (store 4 into %stack.0)
    DBG_VALUE $rsp, 0, !9, !DIExpression(DW_OP_plus_uconst, 16), debug-location !10

    ; This load from the stack can be misinterpreted as a stack restore of
    ; any DBG_VALUe pointing at $rsp.
    $rsi = MOV64rm $rsp, 1, $noreg, 0, $noreg :: (load 8 from %stack.1)

    ; Return faff
    $eax = MOV32ri 0
    $rsp = frame-destroy ADD64ri8 $rsp, 24, implicit-def dead $eflags
    RETQ debug-location !10
...