fe18ab983d
This patch follows on from the changes made in #105524, by adding an additional heuristic that prevents us from applying the start-of-MBB is_stmt flag when we can see that, for all direct branches to the MBB, the last line stepped on before the branch is the same as the first line of the MBB. This is mainly to prevent certain pathological cases, such as macros that expand to multiple basic blocks that all have the same source location, from giving us repeated steps on the same line. This approach is not comprehensive, since it relies on analyzeBranch to read edges, but the default fallback of applying is_stmt may lead only to useless steps in some cases, rather than skipping useful steps altogether.
63 lines
2.7 KiB
LLVM
63 lines
2.7 KiB
LLVM
;; Checks that when an instruction at the start of a BasicBlock has the same
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;; DebugLoc as the instruction at the end of the previous BasicBlock, we add
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;; is_stmt to the new line, to ensure that we still step on it if we arrive from
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;; a BasicBlock other than the immediately preceding one, unless all known
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;; predecessor BasicBlocks end with the same line.
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; RUN: %llc_dwarf -mtriple=x86_64-unknown-linux -O0 -filetype=obj < %s | llvm-dwarfdump --debug-line - | FileCheck %s
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; CHECK: {{0x[0-9a-f]+}} 13 5 {{.+}} is_stmt
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; CHECK-NEXT: {{0x[0-9a-f]+}} 13 5 {{.+}} is_stmt
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define void @_Z1fi(i1 %cond) !dbg !21 {
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entry:
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br i1 %cond, label %if.then2, label %if.else4
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if.then2: ; preds = %entry
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br label %if.end8, !dbg !24
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if.else4: ; preds = %entry
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%0 = load i32, ptr null, align 4, !dbg !24
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%call5 = call i1 null(i32 %0)
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ret void
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if.end8: ; preds = %if.then2
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ret void
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}
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; CHECK: {{0x[0-9a-f]+}} 113 5 {{.+}} is_stmt
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; CHECK-NOT: {{0x[0-9a-f]+}} 113 5
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define void @_Z1gi(i1 %cond) !dbg !31 {
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entry:
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br i1 %cond, label %if.then2, label %if.else4, !dbg !34
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if.then2: ; preds = %entry
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br label %if.end8, !dbg !34
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if.else4: ; preds = %entry
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%0 = load i32, ptr null, align 4, !dbg !34
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%call5 = call i1 null(i32 %0)
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ret void
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if.end8: ; preds = %if.then2
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ret void
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}
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!20}
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 20.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
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!1 = !DIFile(filename: "test.cpp", directory: "/home/gbtozers/dev/upstream-llvm")
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!20 = !{i32 2, !"Debug Info Version", i32 3}
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!21 = distinct !DISubprogram(name: "f", linkageName: "_Z1fi", scope: !1, file: !1, line: 7, type: !22, scopeLine: 7, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0)
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!22 = distinct !DISubroutineType(types: !23)
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!23 = !{null}
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!24 = !DILocation(line: 13, column: 5, scope: !25)
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!25 = distinct !DILexicalBlock(scope: !21, file: !1, line: 11, column: 27)
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!31 = distinct !DISubprogram(name: "g", linkageName: "_Z1gi", scope: !1, file: !1, line: 107, type: !32, scopeLine: 7, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0)
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!32 = distinct !DISubroutineType(types: !33)
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!33 = !{null}
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!34 = !DILocation(line: 113, column: 5, scope: !35)
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!35 = distinct !DILexicalBlock(scope: !31, file: !1, line: 111, column: 27)
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