b8f68ad9cd
It appears that we can emit all the instructions for a function, including debug instructions, and then optimise some of the values out late. Specifically, in the attached test case, an argument gets optimised out after DBG_VALUE / DBG_INSTR_REFs are created. This confuses MachineFunction::finalizeDebugInstrRefs, which expects to be able to find a defining instruction, and crashes instead. Fix this by identifying when there's no defining instruction, and translating that instead into a DBG_VALUE $noreg. Differential Revision: https://reviews.llvm.org/D114476
46 lines
2.0 KiB
LLVM
46 lines
2.0 KiB
LLVM
; RUN: llc %s -o - -stop-before=finalize-isel \
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; RUN: -experimental-debug-variable-locations \
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; RUN: | FileCheck %s
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;; The multiply by zero of %width below causes %width to become unused very late
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;; in SelectionDAG. As a result, DBG_INSTR_REFs are produced that refer to a
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;; vreg that is never defined, which risks a crash. Check that we don't crash,
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;; and produce an empty variable location.
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; CHECK: DBG_VALUE $noreg
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-unknown"
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%class.Color = type { i8 }
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define hidden void @_Z14drawXZWideLineR4Vec3RK5Colorf(%class.Color* %color, float %width) local_unnamed_addr !dbg !7 {
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cond.false.i:
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br label %_ZN4Vec39normalizeEv.exit, !dbg !12
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_ZN4Vec39normalizeEv.exit: ; preds = %cond.false.i
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call void @llvm.dbg.value(metadata float %width, metadata !11, metadata !DIExpression()), !dbg !12
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%mul.i = fmul float %width, 0.000000e+00, !dbg !12
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ret void, !dbg !12
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}
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; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
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declare void @llvm.dbg.value(metadata, metadata, metadata)
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4, !5, !6}
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
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!1 = !DIFile(filename: "foo.cpp", directory: ".")
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!2 = !DIBasicType(name: "int", size: 8, encoding: DW_ATE_signed)
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!3 = !{i32 2, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{i32 1, !"wchar_size", i32 2}
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!6 = !{i32 7, !"PIC Level", i32 2}
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!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)
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!8 = !DISubroutineType(types: !9)
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!9 = !{!2, !2}
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!10 = !{!11}
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!11 = !DILocalVariable(name: "baz", scope: !7, file: !1, line: 7, type: !2)
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!12 = !DILocation(line: 10, scope: !7)
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