1; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -v -debug-info - | FileCheck %s 2 3; Built from the following source with clang -O1 4; struct S { int i; }; 5; int function(struct S s, int i) { return s.i + i; } 6 7; Due to the X86_64 ABI, 's' is passed in registers and once optimized, the 8; entirety of 's' is never reconstituted, since only the int is required, and 9; thus the variable's location is unknown/dead to debug info. 10 11; Future/current work should enable us to describe partial variables, which, in 12; this case, happens to be the entire variable. 13 14; CHECK: DW_TAG_subprogram 15; CHECK-NOT: DW_TAG 16; CHECK: DW_AT_name {{.*}} "function" 17; CHECK-NOT: {{DW_TAG|NULL}} 18; CHECK: DW_TAG_formal_parameter 19; CHECK-NOT: DW_TAG 20; CHECK: DW_AT_name {{.*}} "s" 21; CHECK-NOT: DW_TAG 22; FIXME: Even though 's' is never reconstituted into a struct, the one member 23; variable is still live and used, and so we should be able to describe 's's 24; location as the location of that int. 25; CHECK-NOT: DW_AT_location 26; CHECK-NOT: {{DW_TAG|NULL}} 27; CHECK: DW_TAG_formal_parameter 28; CHECK-NOT: DW_TAG 29; CHECK: DW_AT_location 30; CHECK-NOT: DW_TAG 31; CHECK: DW_AT_name {{.*}} "i" 32 33 34%struct.S = type { i32 } 35 36; Function Attrs: nounwind readnone uwtable 37define i32 @_Z8function1Si(i32 %s.coerce, i32 %i) #0 !dbg !9 { 38entry: 39 tail call void @llvm.dbg.declare(metadata %struct.S* undef, metadata !14, metadata !DIExpression()), !dbg !20 40 tail call void @llvm.dbg.value(metadata i32 %i, metadata !15, metadata !DIExpression()), !dbg !20 41 %add = add nsw i32 %i, %s.coerce, !dbg !20 42 ret i32 %add, !dbg !20 43} 44 45; Function Attrs: nounwind readnone 46declare void @llvm.dbg.declare(metadata, metadata, metadata) #1 47 48; Function Attrs: nounwind readnone 49declare void @llvm.dbg.value(metadata, metadata, metadata) #1 50 51attributes #0 = { nounwind readnone uwtable "less-precise-fpmad"="false" "frame-pointer"="none" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" } 52attributes #1 = { nounwind readnone } 53 54!llvm.dbg.cu = !{!0} 55!llvm.module.flags = !{!16, !17} 56!llvm.ident = !{!18} 57 58!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.5.0 ", isOptimized: true, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !3, globals: !2, imports: !2) 59!1 = !DIFile(filename: "dead-argument-order.cpp", directory: "/tmp/dbginfo") 60!2 = !{} 61!3 = !{!4} 62!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "S", line: 1, size: 32, align: 32, file: !1, elements: !5, identifier: "_ZTS1S") 63!5 = !{!6} 64!6 = !DIDerivedType(tag: DW_TAG_member, name: "i", line: 1, size: 32, align: 32, file: !1, scope: !4, baseType: !7) 65!7 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed) 66!9 = distinct !DISubprogram(name: "function", linkageName: "_Z8function1Si", line: 2, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, unit: !0, scopeLine: 2, file: !1, scope: !10, type: !11, retainedNodes: !13) 67!10 = !DIFile(filename: "dead-argument-order.cpp", directory: "/tmp/dbginfo") 68!11 = !DISubroutineType(types: !12) 69!12 = !{!7, !4, !7} 70!13 = !{!14, !15} 71!14 = !DILocalVariable(name: "s", line: 2, arg: 1, scope: !9, file: !10, type: !4) 72!15 = !DILocalVariable(name: "i", line: 2, arg: 2, scope: !9, file: !10, type: !7) 73!16 = !{i32 2, !"Dwarf Version", i32 4} 74!17 = !{i32 2, !"Debug Info Version", i32 3} 75!18 = !{!"clang version 3.5.0 "} 76!19 = !{%struct.S* undef} 77!20 = !DILocation(line: 2, scope: !9) 78 79