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|
# RUN: llc %s -o - -experimental-debug-variable-locations=true \
# RUN: -run-pass=livedebugvalues \
# RUN: | FileCheck %s --implicit-check-not=DBG_VALUE
# RUN: llc %s -o - -experimental-debug-variable-locations=true \
# RUN: -start-before=livedebugvalues -filetype=obj \
# RUN: | llvm-dwarfdump - | FileCheck %s --check-prefix=DWARF
#
# LLVM can produce DIExpressions that convert from one value of arbitrary size
# to another. This is normally fine, however that means the value for a
# variable tracked in instruction referencing might not be the same size as the
# variable itself.
#
# We typically use vector registers as shorthand for "the lower lane of the
# vector register", for example if we have a single float we might say
#
# DBG_VALUE $xmm0
#
# and that's reflected in DWARF too. However, instruction-referencing tries to
# solve several size problems (see deref-spills-with-size.mir), and gets
# confused by this shorthand. It manifests in the test sequence below: we
# locate a variable in a vector register, spill it, then force a stack variable
# location to be produced. InstrRefBasedLDV would like to produce a
# DW_OP_deref_size indicating that 128 bits should be loaded for the 32 bit
# register, but this would be wrong (and illegal DWARF as the max load size is
# the pointer size).
#
# As a sticking-plaster fix: detect when we're about to emit these illegal
# DWARF locations, and instead use DW_OP_deref_size. There's a small risk we
# read too much or too little data, but it's better than emitting illegal DWARF.
# CHECK: ![[VAR:[0-9]+]] = !DILocalVariable(name: "flannel",
## Check that we're not producing DW_OP_deref_size, instead using the isIndirect
## field of DBG_VALUEs.
# CHECK: DBG_VALUE $xmm0, $noreg,
# CHECK: DBG_VALUE $rsp, 0, ![[VAR]], !DIExpression(DW_OP_plus_uconst, 8),
## Check that we produce a breg location with no further expression attached.
# DWARF: DW_TAG_variable
# DWARF-NEXT: DW_AT_location
# DWARF-NEXT: DW_OP_reg17 XMM0
# DWARF-NEXT: DW_OP_breg7 RSP+8)
# DWARF-NEXT: DW_AT_name ("flannel")
--- |
; ModuleID = 'missingvar.ll'
source_filename = "a"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define linkonce_odr void @_ZNSt5dequeIPN4llvm4LoopESaIS2_EE13_M_insert_auxESt15_Deque_iteratorIS2_RS2_PS2_EmRKS2_() local_unnamed_addr align 2 !dbg !3 {
entry:
call void @llvm.dbg.value(metadata i32 0, metadata !8, metadata !DIExpression()), !dbg !7
call void @llvm.dbg.value(metadata i32 0, metadata !10, metadata !DIExpression()), !dbg !7
ret void
}
declare void @llvm.dbg.value(metadata, metadata, metadata)
!llvm.module.flags = !{!0, !9}
!llvm.dbg.cu = !{!1}
!0 = !{i32 2, !"Debug Info Version", i32 3}
!1 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "beards", isOptimized: true, runtimeVersion: 4, emissionKind: FullDebug)
!2 = !DIFile(filename: "bees.cpp", directory: "")
!3 = distinct !DISubprogram(name: "nope", scope: !2, file: !2, line: 1, type: !4, spFlags: DISPFlagDefinition, unit: !1)
!4 = !DISubroutineType(types: !5)
!5 = !{!6}
!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!7 = !DILocation(line: 1, scope: !3)
!8 = !DILocalVariable(name: "flannel", scope: !3, type: !6)
!9 = !{i32 2, !"Dwarf Version", i32 5}
!10 = !DILocalVariable(name: "shoes", scope: !3, type: !11)
!11 = !DIBasicType(name: "long", size: 64, encoding: DW_ATE_signed)
...
---
name: _ZNSt5dequeIPN4llvm4LoopESaIS2_EE13_M_insert_auxESt15_Deque_iteratorIS2_RS2_PS2_EmRKS2_
alignment: 16
tracksRegLiveness: true
debugInstrRef: true
liveins:
- { reg: '$rdi' }
- { reg: '$rsi' }
- { reg: '$rdx' }
frameInfo:
stackSize: 16
offsetAdjustment: -16
maxAlignment: 16
maxCallFrameSize: 0
stack:
- { id: 6, type: spill-slot, offset: -16, size: 16, alignment: 16 }
machineFunctionInfo: {}
body: |
bb.0.entry:
liveins: $rdi, $rdx, $rsi, $rbp, $xmm0
$xmm0 = XORPSrr $xmm0, $xmm0, debug-location !7
DBG_VALUE $xmm0, $noreg, !8, !DIExpression(), debug-location !7
VMOVUPSmr $rsp, 1, $noreg, 36, $noreg, $xmm0 :: (store (s128) into %stack.6)
$xmm0 = XORPSrr $xmm0, $xmm0, debug-location !7
RET64 0, debug-location !7
...
|
