This is needed for Fortran assumed shape arrays whose dimensions are
defined as,
- 'count' is taken from array descriptor passed as parameter by
caller, access from descriptor is defined by type DIExpression.
- 'lowerBound' is defined by callee.
The current alternate way represents using upperBound in place of
count, where upperBound is calculated in callee in a temp variable
using lowerBound and count
Representation with count (DIExpression) is not only clearer as
compared to upperBound (DIVariable) but it has another advantage that
variable count is accessed by being parameter has better chance of
survival at higher optimization level than upperBound being local
variable.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D99335
38 lines
1.6 KiB
LLVM
38 lines
1.6 KiB
LLVM
; RUN: llvm-as < %s -disable-output 2>&1 | FileCheck %s
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define void @foo(i32 %n) {
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entry:
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%0 = zext i32 %n to i64
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%vla = alloca i32, i64 %0, align 16
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call void @llvm.dbg.declare(metadata i32* %vla, metadata !19, metadata !12), !dbg !18
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ret void
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}
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declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4, !5}
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!llvm.ident = !{!6}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 5.0.1", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
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!1 = !DIFile(filename: "vla.c", directory: "/path/to")
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!2 = !{}
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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 4}
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!6 = !{!"clang version 5.0.1"}
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!7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 20, type: !8, isLocal: false, isDefinition: true, scopeLine: 20, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !11)
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!8 = !DISubroutineType(types: !9)
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!9 = !{null, !10}
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!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!11 = !{!16, !19}
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!12 = !DIExpression()
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!16 = !DILocalVariable(name: "vla_expr", scope: !7, file: !1, line: 21, type: !17)
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!17 = !DIBasicType(name: "long unsigned int", size: 64, encoding: DW_ATE_unsigned)
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!18 = !DILocation(line: 21, column: 7, scope: !7)
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!19 = !DILocalVariable(name: "vla", scope: !7, file: !1, line: 21, type: !20)
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!20 = !DICompositeType(tag: DW_TAG_array_type, baseType: !10, align: 32, elements: !21)
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!21 = !{!22}
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; CHECK: Count must be signed constant or DIVariable or DIExpression
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!22 = !DISubrange(count: !17)
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