# RUN: llc %s -march=x86-64 -run-pass=livedebugvalues -experimental-debug-variable-locations -o - 2>&1 | FileCheck %s
#
# Test that when we have a subregister qualifiers in substitutions, that
# InstrRefBasedLDV correctly applies them to the variable location. Below, a
# call defines all of $rax, but the variable locations should only apply to
# the low order 8 bits.
--- |
define i8 @test(i32 %bar) local_unnamed_addr !dbg !7 {
entry:
ret i8 0, !dbg !12
}
declare dso_local void @ext(i64)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4, !5, !6}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
!1 = !DIFile(filename: "foo.cpp", directory: ".")
!2 = !DIBasicType(name: "int", size: 8, encoding: DW_ATE_signed)
!3 = !{i32 2, !"Dwarf Version", i32 4}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!5 = !{i32 1, !"wchar_size", i32 2}
!6 = !{i32 7, !"PIC Level", i32 2}
!7 = distinct !DISubprogram(name: "foo", linkageName: "foo", scope: !1, file: !1, line: 6, type: !8, scopeLine: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !10)
!8 = !DISubroutineType(types: !9)
!9 = !{!2, !2}
!10 = !{!11}
!11 = !DILocalVariable(name: "baz", scope: !7, file: !1, line: 7, type: !2)
!12 = !DILocation(line: 10, scope: !7)
...
---
name: test
tracksRegLiveness: true
debugInstrRef: true
liveins:
- { reg: '$rdi', virtual-reg: '' }
debugValueSubstitutions:
- { srcinst: 1, srcop: 0, dstinst: 2, dstop: 0, subreg: 1 } # sub_8bit
- { srcinst: 2, srcop: 0, dstinst: 3, dstop: 0, subreg: 4 } # sub_16bit
- { srcinst: 3, srcop: 0, dstinst: 4, dstop: 5, subreg: 6 } # sub_32bit
# Substitution involving sub_8bit_hi, should land in $ah
- { srcinst: 5, srcop: 0, dstinst: 6, dstop: 0, subreg: 2 } # sub_8bit_hi
- { srcinst: 6, srcop: 0, dstinst: 7, dstop: 0, subreg: 4 } # sub_16bit
- { srcinst: 7, srcop: 0, dstinst: 4, dstop: 5, subreg: 6 } # sub_32bit
# Several redundant substitutions, representing extractions from a small
# register, followed by larger spurious ones, for example:
# %0:gr64 = COPY $rax
# %1:gr32 = COPY %0.sub_32bit
# %2:gr16 = COPY %1.sub_16bit
# %3:gr64 = SUBREG_TO_REG %2, sub_8bit_hi
# %4:gr32 = COPY %3.sub_32bit
# %5:gr16 = COPY %2.sub_16bit
# Should still come out as ah.
- { srcinst: 8, srcop: 0, dstinst: 9, dstop: 0, subreg: 4 } # sub_16bit
- { srcinst: 9, srcop: 0, dstinst: 10,dstop: 0, subreg: 6 } # sub_32bit
- { srcinst: 10,srcop: 0, dstinst: 11,dstop: 0, subreg: 2 } # sub_8bit_hi
- { srcinst: 11,srcop: 0, dstinst: 12,dstop: 0, subreg: 4 } # sub_16bit
- { srcinst: 12,srcop: 0, dstinst: 4, dstop: 5, subreg: 6 } # sub_32bit
# If some kind of really mal-formed code appears that extracts the high bits
# out of a too-small location, we should drop it. It's not clear whether this
# scenario could ever happen; but if it did, best to not emit a known bad
# variable location. Should generate a DBG_VALUE $noreg.
- { srcinst: 13, srcop: 0, dstinst: 14,dstop: 0, subreg: 5 } # sub_16bit_hi
- { srcinst: 14, srcop: 0, dstinst: 15,dstop: 0, subreg: 6 } # sub_32bit
- { srcinst: 15, srcop: 0, dstinst: 4, dstop: 5, subreg: 1 } # sub_8bit
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: '' }
body: |
bb.0:
liveins: $rdi, $rax
CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit $edi, implicit-def $rax, debug-instr-number 4, debug-location !12
; CHECK: CALL64pcrel32
DBG_INSTR_REF !11, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(1, 0), debug-location !12
; CHECK-NEXT: DBG_INSTR_REF {{.+}}, dbg-instr-ref(1, 0)
; CHECK-NEXT: DBG_VALUE_LIST {{.+}}, $al
DBG_INSTR_REF !11, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(5, 0), debug-location !12
; CHECK-NEXT: DBG_INSTR_REF {{.+}}, dbg-instr-ref(5, 0)
; CHECK-NEXT: DBG_VALUE_LIST {{.+}}, $ah
DBG_INSTR_REF !11, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(8, 0), debug-location !12
; CHECK-NEXT: DBG_INSTR_REF {{.+}}, dbg-instr-ref(8, 0)
; CHECK-NEXT: DBG_VALUE_LIST {{.+}}, $ah
DBG_INSTR_REF !11, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(13, 0), debug-location !12
; CHECK-NEXT: DBG_INSTR_REF {{.+}}, dbg-instr-ref(13, 0)
; CHECK-NEXT: DBG_VALUE_LIST {{.+}}, $noreg
MOV64mr $rsp, 1, $noreg, 16, $noreg, $rax :: (store 8 into %stack.0)
$rax = MOV64ri 0, debug-location !12
; CHECK: $rax = MOV64ri 0
; The value is now located in a spill slot, as a subregister within the
; slot, which InstrRefBasedLDV should be able to find.
DBG_INSTR_REF !11, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(1, 0), debug-location !12
; CHECK-NEXT: DBG_INSTR_REF {{.+}}, dbg-instr-ref(1, 0)
; CHECK-NEXT: DBG_VALUE_LIST !{{[0-9]*}}, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_constu, 8, DW_OP_minus, DW_OP_deref), $rsp
DBG_INSTR_REF !11, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(5, 0), debug-location !12
; This and the next DBG_INSTR_REF refer to a value that is on the stack, but
; is located at a non-zero offset from the start of the slot -- $ah within
; $rax is 8 bits in. Today, InstrRefBasedLDV can't express this. It also
; doesn't seem likely to be profitable.
; CHECK-NEXT: DBG_INSTR_REF {{.+}}, dbg-instr-ref(5, 0)
; CHECK-NEXT: DBG_VALUE_LIST {{.+}}, $noreg
DBG_INSTR_REF !11, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(8, 0), debug-location !12
; CHECK-NEXT: DBG_INSTR_REF {{.+}}, dbg-instr-ref(8, 0)
; CHECK-NEXT: DBG_VALUE_LIST {{.+}}, $noreg
DBG_INSTR_REF !11, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(13, 0), debug-location !12
; CHECK-NEXT: DBG_INSTR_REF {{.+}}, dbg-instr-ref(13, 0)
; CHECK-NEXT: DBG_VALUE_LIST {{.+}}, $noreg
$rax = MOV64rm $rsp, 1, $noreg, 8, $noreg :: (load 8 from %stack.0)
RET64 $rax, debug-location !12
...
Codebase Browser
llvm