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When instructions are hoisted out of loops by MachineLICM, remove the…
…ir debug loc. This prevents erratic stepping behavior as well as incorrect source attribution for sample profiling. Reviewers: dblakie Subscribers: llvm-commit Differential Revision: https://reviews.llvm.org/D27290 llvm-svn: 288442
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,141 @@ | ||
--- | | ||
; RUN: llc -run-pass=machinelicm -o - %s | FileCheck %s | ||
; Line numbers should not be retained when loop invariant instructions are hoisted. | ||
; Doing so causes poor stepping bevavior. | ||
; | ||
; Created from: | ||
; int x; | ||
; void Process(const unsigned int *p) | ||
; { | ||
; while (1) | ||
; x = *p++; | ||
; } | ||
; | ||
; with clang -emit-llvm -S -O2 -g -o t.ll t.c | ||
; llc -relocation-model=pic -stop-after=machine-combine -O2 t.ll -o t.mir | ||
; | ||
; We check that when the machine loop invariant pass hoists instructions | ||
; out of a loop the debug information is not retained. | ||
; | ||
; CHECK-LABEL: bb.0.entry: | ||
; CHECK: MOV64rm %rip, 1, _, target-flags(x86-gotpcrel) @x, _ :: (load 8 from got) | ||
; CHECK-LABEL: bb.1.while.body: | ||
; | ||
; ModuleID = 'tx.ll' | ||
source_filename = "t.c" | ||
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" | ||
target triple = "x86_64-unknown-linux-gnu" | ||
|
||
@x = common local_unnamed_addr global i32 0, align 4, !dbg !0 | ||
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; Function Attrs: noreturn nounwind uwtable | ||
define void @Process(i32* nocapture readonly %p) local_unnamed_addr #0 !dbg !9 { | ||
entry: | ||
tail call void @llvm.dbg.value(metadata i32* %p, i64 0, metadata !16, metadata !17), !dbg !18 | ||
br label %while.body, !dbg !19 | ||
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while.body: ; preds = %while.body, %entry | ||
%p.addr.0 = phi i32* [ %p, %entry ], [ %incdec.ptr, %while.body ] | ||
tail call void @llvm.dbg.value(metadata i32* %p.addr.0, i64 0, metadata !16, metadata !17), !dbg !18 | ||
%incdec.ptr = getelementptr inbounds i32, i32* %p.addr.0, i64 1, !dbg !20 | ||
tail call void @llvm.dbg.value(metadata i32* %incdec.ptr, i64 0, metadata !16, metadata !17), !dbg !18 | ||
%0 = load i32, i32* %p.addr.0, align 4, !dbg !21, !tbaa !22 | ||
store i32 %0, i32* @x, align 4, !dbg !26, !tbaa !22 | ||
br label %while.body, !dbg !27, !llvm.loop !29 | ||
} | ||
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; Function Attrs: nounwind readnone | ||
declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1 | ||
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attributes #0 = { noreturn nounwind uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" } | ||
attributes #1 = { nounwind readnone } | ||
attributes #2 = { nounwind } | ||
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!llvm.dbg.cu = !{!1} | ||
!llvm.module.flags = !{!6, !7} | ||
!llvm.ident = !{!8} | ||
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!0 = distinct !DIGlobalVariable(name: "x", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true) | ||
!1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, producer: "clang version 4.0.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !3, globals: !4) | ||
!2 = !DIFile(filename: "t.c", directory: "/home/test") | ||
!3 = !{} | ||
!4 = !{!0} | ||
!5 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) | ||
!6 = !{i32 2, !"Dwarf Version", i32 4} | ||
!7 = !{i32 2, !"Debug Info Version", i32 3} | ||
!8 = !{!"clang version 4.0.0 "} | ||
!9 = distinct !DISubprogram(name: "Process", scope: !2, file: !2, line: 2, type: !10, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !1, variables: !15) | ||
!10 = !DISubroutineType(types: !11) | ||
!11 = !{null, !12} | ||
!12 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !13, size: 64) | ||
!13 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !14) | ||
!14 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned) | ||
!15 = !{!16} | ||
!16 = !DILocalVariable(name: "p", arg: 1, scope: !9, file: !2, line: 2, type: !12) | ||
!17 = !DIExpression() | ||
!18 = !DILocation(line: 2, column: 34, scope: !9) | ||
!19 = !DILocation(line: 4, column: 3, scope: !9) | ||
!20 = !DILocation(line: 5, column: 11, scope: !9) | ||
!21 = !DILocation(line: 5, column: 9, scope: !9) | ||
!22 = !{!23, !23, i64 0} | ||
!23 = !{!"int", !24, i64 0} | ||
!24 = !{!"omnipotent char", !25, i64 0} | ||
!25 = !{!"Simple C/C++ TBAA"} | ||
!26 = !DILocation(line: 5, column: 7, scope: !9) | ||
!27 = !DILocation(line: 4, column: 3, scope: !28) | ||
!28 = !DILexicalBlockFile(scope: !9, file: !2, discriminator: 1) | ||
!29 = distinct !{!29, !19, !20} | ||
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... | ||
--- | ||
name: Process | ||
alignment: 4 | ||
exposesReturnsTwice: false | ||
legalized: false | ||
regBankSelected: false | ||
selected: false | ||
tracksRegLiveness: true | ||
registers: | ||
- { id: 0, class: gr64 } | ||
- { id: 1, class: gr64 } | ||
- { id: 2, class: gr64 } | ||
- { id: 3, class: gr32 } | ||
- { id: 4, class: gr64 } | ||
liveins: | ||
- { reg: '%rdi', virtual-reg: '%2' } | ||
frameInfo: | ||
isFrameAddressTaken: false | ||
isReturnAddressTaken: false | ||
hasStackMap: false | ||
hasPatchPoint: false | ||
stackSize: 0 | ||
offsetAdjustment: 0 | ||
maxAlignment: 0 | ||
adjustsStack: false | ||
hasCalls: false | ||
maxCallFrameSize: 0 | ||
hasOpaqueSPAdjustment: false | ||
hasVAStart: false | ||
hasMustTailInVarArgFunc: false | ||
body: | | ||
bb.0.entry: | ||
successors: %bb.1.while.body(0x80000000) | ||
liveins: %rdi | ||
DBG_VALUE debug-use %rdi, debug-use _, !16, !17, debug-location !18 | ||
%2 = COPY %rdi | ||
DBG_VALUE debug-use %2, debug-use _, !16, !17, debug-location !18 | ||
bb.1.while.body: | ||
successors: %bb.1.while.body(0x80000000) | ||
%0 = PHI %2, %bb.0.entry, %1, %bb.1.while.body | ||
DBG_VALUE debug-use %0, debug-use _, !16, !17, debug-location !18 | ||
%1 = ADD64ri8 %0, 4, implicit-def dead %eflags, debug-location !20 | ||
DBG_VALUE debug-use %1, debug-use _, !16, !17, debug-location !18 | ||
%3 = MOV32rm %0, 1, _, 0, _, debug-location !21 :: (load 4 from %ir.p.addr.0, !tbaa !22) | ||
%4 = MOV64rm %rip, 1, _, target-flags(x86-gotpcrel) @x, _, debug-location !26 :: (load 8 from got) | ||
MOV32mr killed %4, 1, _, 0, _, killed %3, debug-location !26 :: (store 4 into @x, !tbaa !22) | ||
JMP_1 %bb.1.while.body, debug-location !27 | ||
... |