1; RUN: llc %s -o %t.s 2; RUN: llvm-mc %t.s -filetype=obj -triple=x86_64-windows-msvc -o %t.o 3; RUN: FileCheck %s < %t.s --check-prefix=ASM 4; RUN: llvm-dwarfdump %t.o | FileCheck %s --check-prefix=DWARF 5 6; In this example, the variable lives mostly in memory, but at the point of the 7; assignment to global, it lives nowhere, and is described as the constant 8; value 1. 9 10; C source: 11; 12; void escape(int *); 13; extern int global; 14; void f(int x) { 15; escape(&x); 16; x = 1; // DSE should delete and insert dbg.value(i32 1) 17; global = x; 18; x = 2; // DSE should insert dbg.addr 19; escape(&x); 20; } 21 22; ModuleID = 'dse.c' 23source_filename = "dse.c" 24target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128" 25target triple = "x86_64-pc-windows-msvc19.0.24215" 26 27declare void @llvm.dbg.addr(metadata, metadata, metadata) #2 28declare void @llvm.dbg.value(metadata, metadata, metadata) #2 29declare void @escape(i32*) 30 31@global = external global i32, align 4 32 33; Function Attrs: nounwind uwtable 34define void @f(i32 %x) #0 !dbg !8 { 35entry: 36 %x.addr = alloca i32, align 4 37 store i32 %x, i32* %x.addr, align 4 38 call void @llvm.dbg.addr(metadata i32* %x.addr, metadata !13, metadata !DIExpression()), !dbg !18 39 call void @escape(i32* %x.addr), !dbg !19 40 call void @llvm.dbg.value(metadata i32 1, metadata !13, metadata !DIExpression()), !dbg !20 41 store i32 1, i32* @global, align 4, !dbg !22 42 call void @llvm.dbg.addr(metadata i32* %x.addr, metadata !13, metadata !DIExpression()), !dbg !23 43 store i32 2, i32* %x.addr, align 4, !dbg !23 44 call void @escape(i32* %x.addr), !dbg !24 45 ret void, !dbg !25 46} 47 48; ASM-LABEL: f: # @f 49; ASM: movl %ecx, [[OFF_X:[0-9]+]](%rsp) 50; ASM: #DEBUG_VALUE: f:x <- [DW_OP_plus_uconst [[OFF_X]]] [$rsp+0] 51; ASM: callq escape 52; ASM: #DEBUG_VALUE: f:x <- 1 53; ASM: movl $1, global(%rip) 54; FIXME: Needs a fix to LiveDebugVariables 55; ASMX: #DEBUG_VALUE: f:x <- [DW_OP_plus_uconst [[OFF_X]]] [$rsp+0] 56; ASM: movl $2, [[OFF_X]](%rsp) 57; ASM: callq escape 58; ASM: retq 59 60; DWARF: DW_TAG_formal_parameter 61; DWARF-NEXT: DW_AT_location (0x00000000 62; DWARF-NEXT: {{[^:]*}}: DW_OP_breg7 RSP+{{[0-9]+}} 63; DWARF-NEXT: {{[^:]*}}: DW_OP_consts +1, DW_OP_stack_value 64; DWARF-NEXT: {{[^:]*}}: DW_OP_breg7 RSP+{{[0-9]+}}) 65; DWARF-NEXT: DW_AT_name ("x") 66 67attributes #0 = { nounwind uwtable } 68attributes #2 = { nounwind readnone speculatable } 69 70!llvm.dbg.cu = !{!0} 71!llvm.module.flags = !{!3, !4, !5, !6} 72!llvm.ident = !{!7} 73 74!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) 75!1 = !DIFile(filename: "dse.c", directory: "C:\5Csrc\5Cllvm-project\5Cbuild") 76!2 = !{} 77!3 = !{i32 2, !"Dwarf Version", i32 4} 78!4 = !{i32 2, !"Debug Info Version", i32 3} 79!5 = !{i32 1, !"wchar_size", i32 2} 80!6 = !{i32 7, !"PIC Level", i32 2} 81!7 = !{!"clang version 6.0.0 "} 82!8 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 3, type: !9, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !12) 83!9 = !DISubroutineType(types: !10) 84!10 = !{null, !11} 85!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) 86!12 = !{!13} 87!13 = !DILocalVariable(name: "x", arg: 1, scope: !8, file: !1, line: 3, type: !11) 88!14 = !{!15, !15, i64 0} 89!15 = !{!"int", !16, i64 0} 90!16 = !{!"omnipotent char", !17, i64 0} 91!17 = !{!"Simple C/C++ TBAA"} 92!18 = !DILocation(line: 3, column: 12, scope: !8) 93!19 = !DILocation(line: 4, column: 3, scope: !8) 94!20 = !DILocation(line: 5, column: 5, scope: !8) 95!21 = !DILocation(line: 6, column: 12, scope: !8) 96!22 = !DILocation(line: 6, column: 10, scope: !8) 97!23 = !DILocation(line: 7, column: 5, scope: !8) 98!24 = !DILocation(line: 8, column: 3, scope: !8) 99!25 = !DILocation(line: 9, column: 1, scope: !8) 100