| --- | |
| ; RUN: llc %s -march=x86-64 -run-pass=livedebugvalues -o - -experimental-debug-variable-locations | FileCheck %s -implicit-check-not=DBG_VALUE |
| |
| define i32 @_Z8bb_to_bb() local_unnamed_addr !dbg !12 { |
| entry: |
| ret i32 0, !dbg !17 |
| } |
| |
| !llvm.dbg.cu = !{!0} |
| !llvm.module.flags = !{!7, !8, !9, !10} |
| !llvm.ident = !{!11} |
| !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 10.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3, debugInfoForProfiling: true, nameTableKind: None) |
| !1 = !DIFile(filename: "main.cpp", directory: "F:\") |
| !2 = !{} |
| !3 = !{!4} |
| !4 = !DIGlobalVariableExpression(var: !5, expr: !DIExpression()) |
| !5 = distinct !DIGlobalVariable(name: "start", scope: !0, file: !1, line: 4, type: !6, isLocal: false, isDefinition: true) |
| !6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) |
| !7 = !{i32 2, !"Dwarf Version", i32 4} |
| !8 = !{i32 2, !"Debug Info Version", i32 3} |
| !9 = !{i32 1, !"wchar_size", i32 2} |
| !10 = !{i32 7, !"PIC Level", i32 2} |
| !11 = !{!"clang version 10.0.0"} |
| !12 = distinct !DISubprogram(name: "bb_to_bb", linkageName: "bb_to_bb", scope: !1, file: !1, line: 6, type: !13, scopeLine: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !15) |
| !13 = !DISubroutineType(types: !14) |
| !14 = !{!6, !6} |
| !15 = !{!16} |
| !16 = !DILocalVariable(name: "myVar", scope: !12, file: !1, line: 7, type: !6) |
| !17 = !DILocation(line: 10, scope: !12) |
| |
| ... |
| --- |
| name: _Z8bb_to_bb |
| debugValueSubstitutions: |
| - { srcinst: 4, srcop: 0, dstinst: 3, dstop: 0, subreg: 0 } |
| body: | |
| bb.0.entry: |
| $rax = MOV64ri 1, debug-instr-number 1, debug-location !17 |
| ; This debug instruction should identify the value as being in $rax. |
| DBG_INSTR_REF 1, 0, !16, !DIExpression(), debug-location !17 |
| ; CHECK: DBG_VALUE $rax, $noreg |
| |
| $rbx = COPY killed $rax, debug-location !17 |
| $rax = MOV64ri 1, debug-location !17 |
| ; CHECK: DBG_VALUE $rbx, $noreg |
| |
| DBG_INSTR_REF 2, 0, !16, !DIExpression(), debug-location !17 |
| ; No instruction is labelled with the number "2". This should produce an |
| ; empty variable location. |
| ; CHECK: DBG_VALUE $noreg, $noreg |
| |
| $rbx = MOV64ri 1, debug-instr-number 3, debug-location !17 |
| JMP_1 %bb.1 |
| |
| |
| ; CHECK-LABEL: bb.1: |
| bb.1: |
| |
| DBG_INSTR_REF 3, 0, !16, !DIExpression(), debug-location !17 |
| ; This refers to a value def'd in a parent block -- but it should be |
| ; tracked into this block. |
| ; CHECK: DBG_VALUE $rbx, $noreg |
| JMP_1 %bb.2 |
| |
| ; CHECK-LABEL: bb.2: |
| bb.2: |
| ; Just like any other variable location, live-ins should be created for |
| ; any successor blocks. |
| ; CHECK: DBG_VALUE $rbx, $noreg |
| |
| DBG_INSTR_REF 5, 0, !16, !DIExpression(), debug-location !17 |
| ; This is a debug use-before-def: the value appears a few instructions |
| ; later. Any earlier value should be terminated here, _and_ we should |
| ; emit a DBG_VALUE when the value becomes available. |
| ; CHECK: DBG_VALUE $noreg, $noreg |
| |
| $rax = MOV64ri 1, debug-location !17 |
| $rax = MOV64ri 1, debug-location !17 |
| $rcx = MOV64ri 1, debug-instr-number 5, debug-location !17 |
| ; CHECK: DBG_VALUE $rcx, $noreg |
| $rax = MOV64ri 1, debug-location !17 |
| |
| DBG_INSTR_REF 6, 0, !16, !DIExpression(), debug-location !17 |
| ; Another debug use-before-def, but across block boundaries. |
| ; CHECK: DBG_VALUE $noreg, $noreg |
| JMP_1 %bb.3 |
| |
| ; CHECK-LABEL: bb.3: |
| bb.3: |
| $rax = MOV64ri 1, debug-location !17 |
| $rdx = MOV64ri 1, debug-instr-number 6, debug-location !17 |
| ; CHECK: DBG_VALUE $rdx, $noreg |
| |
| ; Terminate variable location for next few blocks, |
| DBG_VALUE $noreg, $noreg, !16, !DIExpression(), debug-location !17 |
| ; CHECK: DBG_VALUE $noreg, $noreg |
| JMP_1 %bb.4 |
| |
| bb.4: |
| ; The next three blocks form a debug use-before-def modelling a scenario |
| ; where an instruction is sunk (debug inst in bb5, value in bb6). However, |
| ; because a different path joins bb.6, we should _not_ add any DBG_VALUE. |
| ; A different variable value may enter the block via the other path. |
| $rdx = MOV64ri 1, implicit-def $eflags, debug-location !17 |
| JCC_1 %bb.6, 4, implicit $eflags, debug-location !17 |
| bb.5: |
| DBG_INSTR_REF 7, 0, !16, !DIExpression(), debug-location !17 |
| ; CHECK: DBG_VALUE $noreg, $noreg |
| JMP_1 %bb.6, debug-location !17 |
| bb.6: |
| $rsi = MOV64ri 1, debug-instr-number 7, debug-location !17 |
| JMP_1 %bb.7, debug-location !17 |
| |
| ; A use-before-def shouldn't pass another definition of the variable location |
| ; or value. |
| bb.7: |
| DBG_INSTR_REF 8, 0, !16, !DIExpression(), debug-location !17 |
| ; CHECK: DBG_VALUE $noreg, $noreg |
| DBG_VALUE $rax, $noreg, !16, !DIExpression(), debug-location !17 |
| ; CHECK: DBG_VALUE $rax, $noreg, |
| $rdi = MOV64ri 1, debug-instr-number 8, debug-location !17 |
| |
| ; Loops: use-before-defs should be live-through loops, assuming that nothing |
| ; in that loop modifies the variable location. |
| bb.8: |
| DBG_INSTR_REF 9, 0, !16, !DIExpression(), debug-location !17 |
| ; CHECK: DBG_VALUE $noreg, $noreg |
| JCC_1 %bb.8, 4, implicit $eflags |
| bb.9: |
| $rax = MOV64ri 11, debug-instr-number 9, debug-location !17 |
| ; CHECK: DBG_VALUE $rax, $noreg, |
| |
| ; Likewise, use-before-defs where anything changes the variable location |
| ; or value in the loop, should be discarded. |
| bb.10: |
| ; live-in, |
| ; CHECK: DBG_VALUE $rax, $noreg, |
| DBG_INSTR_REF 10, 0, !16, !DIExpression(), debug-location !17 |
| ; CHECK: DBG_VALUE $noreg, $noreg |
| |
| bb.11: |
| $rbx = MOV64ri 1, debug-location !17 |
| |
| bb.12: |
| DBG_INSTR_REF 9, 0, !16, !DIExpression(), debug-location !17 |
| ; This still has a value in $rax, |
| ; CHECK: DBG_VALUE $rax, $noreg |
| JCC_1 %bb.11, 4, implicit $eflags |
| |
| bb.13: |
| ; Live in, |
| ; CHECK: DBG_VALUE $rax, $noreg |
| $rbx = MOV64ri 11, debug-instr-number 10, debug-location !17 |
| ; This is instruction 10 referred to in bb.10. However, as the variable |
| ; location/value has been modified in the meantime, no DBG_VALUE should be |
| ; generated here. |
| RET64 $eax, debug-location !17 |
| ... |