1575583f2a
This patch adds support to the instruction-referencing LiveDebugValues implementation for emitting entry values. The instruction referencing implementations tracking by value rather than location means that we can get around two of the issues with VarLocs. DBG_VALUE instructions that re-assign the same value to a variable are no longer a problem, because we can "see through" to the value being assigned. We also don't need to do anything special during the dataflow stages: the "variable value problem" doesn't need to know whether a value is available most of the time, and the times it deoes need to know are always when entry values need to be terminated. The patch modifies the "TransferTracker" class, adding methods to identify when a variable ias an entry value candidate, and when a machine value is an entry value. recoverAsEntryValue tests these two things and emits an entry-value expression if they're true. It's used when we clobber or otherwise lose a value and can't find a replacement location for the value it contained. Differential Revision: https://reviews.llvm.org/D88406
79 lines
3.9 KiB
LLVM
79 lines
3.9 KiB
LLVM
;; Test mips32:
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; RUN: llc -emit-call-site-info -stop-after=livedebugvalues -mtriple=mips-linux-gnu -o - %s | FileCheck %s
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; RUN: llc -force-instr-ref-livedebugvalues=1 -emit-call-site-info -stop-after=livedebugvalues -mtriple=mips-linux-gnu -o - %s | FileCheck %s
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;; Test mipsel:
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; RUN: llc -emit-call-site-info -stop-after=livedebugvalues -mtriple=mipsel-linux-gnu -o - %s | FileCheck %s --check-prefix=CHECKel
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; RUN: llc -force-instr-ref-livedebugvalues=1 -emit-call-site-info -stop-after=livedebugvalues -mtriple=mipsel-linux-gnu -o - %s | FileCheck %s --check-prefix=CHECKel
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;; Built from source:
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;; extern long fn1(long,long,long);
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;; long fn2(long a, long b, long c) {
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;; long local = fn1(a+b, c, b+10);
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;; if (local > 10)
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;; return local + 10;
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;; return b;
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;; }
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;; Using command:
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;; clang -g -O2 -target mips-linux-gnu m.c -c -S -emit-llvm
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;; Confirm that info from callSites attribute is used as entry_value in DIExpression.
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;; Test mips32:
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; CHECK: $a0 = nsw ADDu $a1, killed renamable $a0,
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; CHECK-NEXT: DBG_VALUE $a0, $noreg, !14, !DIExpression(DW_OP_LLVM_entry_value, 1)
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;; Test mipsel:
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; CHECKel: $a0 = nsw ADDu $a1, killed renamable $a0,
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; CHECKel-NEXT: DBG_VALUE $a0, $noreg, !14, !DIExpression(DW_OP_LLVM_entry_value, 1)
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; ModuleID = 'm.c'
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source_filename = "m.c"
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target datalayout = "E-m:m-p:32:32-i8:8:32-i16:16:32-i64:64-n32-S64"
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target triple = "mips-unknown-linux-gnu"
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; Function Attrs: nounwind
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define dso_local i32 @fn2(i32 signext %a, i32 signext %b, i32 signext %c) local_unnamed_addr !dbg !12 {
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entry:
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call void @llvm.dbg.value(metadata i32 %a, metadata !14, metadata !DIExpression()), !dbg !18
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call void @llvm.dbg.value(metadata i32 %b, metadata !15, metadata !DIExpression()), !dbg !18
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call void @llvm.dbg.value(metadata i32 %c, metadata !16, metadata !DIExpression()), !dbg !18
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%add = add nsw i32 %b, %a, !dbg !18
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%add1 = add nsw i32 %b, 10, !dbg !18
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%call = tail call i32 @fn1(i32 signext %add, i32 signext %c, i32 signext %add1), !dbg !18
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call void @llvm.dbg.value(metadata i32 %call, metadata !17, metadata !DIExpression()), !dbg !18
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%cmp = icmp sgt i32 %call, 10, !dbg !22
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%add2 = add nsw i32 %call, 10, !dbg !18
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%retval.0 = select i1 %cmp, i32 %add2, i32 %b, !dbg !18
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ret i32 %retval.0, !dbg !18
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}
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declare !dbg !4 dso_local i32 @fn1(i32 signext, i32 signext, i32 signext) local_unnamed_addr
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; Function Attrs: nounwind readnone speculatable willreturn
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declare void @llvm.dbg.value(metadata, metadata, metadata)
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!8, !9, !10}
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!llvm.ident = !{!11}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 11.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, splitDebugInlining: false, nameTableKind: None)
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!1 = !DIFile(filename: "m.c", directory: "/dir")
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!2 = !{}
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!3 = !{!4}
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!4 = !DISubprogram(name: "fn1", scope: !1, file: !1, line: 1, type: !5, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
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!5 = !DISubroutineType(types: !6)
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!6 = !{!7, !7, !7, !7}
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!7 = !DIBasicType(name: "long int", size: 32, encoding: DW_ATE_signed)
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!8 = !{i32 7, !"Dwarf Version", i32 4}
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!9 = !{i32 2, !"Debug Info Version", i32 3}
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!10 = !{i32 1, !"wchar_size", i32 4}
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!11 = !{!"clang version 11.0.0"}
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!12 = distinct !DISubprogram(name: "fn2", scope: !1, file: !1, line: 2, type: !5, scopeLine: 2, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !13)
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!13 = !{!14, !15, !16, !17}
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!14 = !DILocalVariable(name: "a", arg: 1, scope: !12, file: !1, line: 2, type: !7)
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!15 = !DILocalVariable(name: "b", arg: 2, scope: !12, file: !1, line: 2, type: !7)
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!16 = !DILocalVariable(name: "c", arg: 3, scope: !12, file: !1, line: 2, type: !7)
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!17 = !DILocalVariable(name: "local", scope: !12, file: !1, line: 3, type: !7)
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!18 = !DILocation(line: 0, scope: !12)
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!22 = !DILocation(line: 4, column: 13, scope: !23)
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!23 = distinct !DILexicalBlock(scope: !12, file: !1, line: 4, column: 7)
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