In order to set breakpoints on labels and list source code around labels, we need collect debug information for labels, i.e., label name, the function label belong, line number in the file, and the address label located. In order to keep these information in LLVM IR and to allow backend to generate debug information correctly. We create a new kind of metadata for labels, DILabel. The format of DILabel is !DILabel(scope: !1, name: "foo", file: !2, line: 3) We hope to keep debug information as much as possible even the code is optimized. So, we create a new kind of intrinsic for label metadata to avoid the metadata is eliminated with basic block. The intrinsic will keep existing if we keep it from optimized out. The format of the intrinsic is llvm.dbg.label(metadata !1) It has only one argument, that is the DILabel metadata. The intrinsic will follow the label immediately. Backend could get the label metadata through the intrinsic's parameter. We also create DIBuilder API for labels to be used by Frontend. Frontend could use createLabel() to allocate DILabel objects, and use insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR. Differential Revision: https://reviews.llvm.org/D45024 Patch by Hsiangkai Wang. llvm-svn: 331841
77 lines
3.5 KiB
LLVM
77 lines
3.5 KiB
LLVM
; RUN: opt < %s -add-discriminators -S | FileCheck %s
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; RUN: opt < %s -passes=add-discriminators -S | FileCheck %s
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; We should not generate discriminators for DWARF versions prior to 4.
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;
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; Original code:
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;
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; int foo(long i) {
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; if (i < 5) return 2; else return 90;
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; }
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;
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; None of the !dbg nodes associated with the if() statement should be
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; altered. If they are, it means that the discriminators pass added a
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; new lexical scope.
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define i32 @foo(i64 %i) #0 !dbg !4 {
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entry:
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%retval = alloca i32, align 4
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%i.addr = alloca i64, align 8
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store i64 %i, i64* %i.addr, align 8
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call void @llvm.dbg.declare(metadata i64* %i.addr, metadata !13, metadata !DIExpression()), !dbg !14
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%0 = load i64, i64* %i.addr, align 8, !dbg !15
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; CHECK: %0 = load i64, i64* %i.addr, align 8, !dbg ![[ENTRY:[0-9]+]]
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%cmp = icmp slt i64 %0, 5, !dbg !15
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; CHECK: %cmp = icmp slt i64 %0, 5, !dbg ![[ENTRY:[0-9]+]]
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br i1 %cmp, label %if.then, label %if.else, !dbg !15
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; CHECK: br i1 %cmp, label %if.then, label %if.else, !dbg ![[ENTRY:[0-9]+]]
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if.then: ; preds = %entry
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store i32 2, i32* %retval, !dbg !15
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br label %return, !dbg !15
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if.else: ; preds = %entry
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store i32 90, i32* %retval, !dbg !15
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br label %return, !dbg !15
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return: ; preds = %if.else, %if.then
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%1 = load i32, i32* %retval, !dbg !17
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ret i32 %1, !dbg !17
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}
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; Function Attrs: nounwind readnone
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declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
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attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
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attributes #1 = { nounwind readnone }
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; We should be able to add discriminators even in the absence of llvm.dbg.cu.
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; When using sample profiles, the front end will generate line tables but it
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; does not generate llvm.dbg.cu to prevent codegen from emitting debug info
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; to the final binary.
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!10, !11}
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!llvm.ident = !{!12}
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; CHECK: !{i32 2, !"Dwarf Version", i32 2}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.5.0 ", isOptimized: false, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
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!1 = !DIFile(filename: "no-discriminators", directory: ".")
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!2 = !{}
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!4 = distinct !DISubprogram(name: "foo", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 1, file: !1, scope: !5, type: !6, retainedNodes: !2)
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; CHECK: ![[FOO:[0-9]+]] = distinct !DISubprogram(name: "foo"
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!5 = !DIFile(filename: "no-discriminators", directory: ".")
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!6 = !DISubroutineType(types: !7)
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!7 = !{!8, !9}
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!8 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
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!9 = !DIBasicType(tag: DW_TAG_base_type, name: "long int", size: 64, align: 64, encoding: DW_ATE_signed)
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!10 = !{i32 2, !"Dwarf Version", i32 2}
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!11 = !{i32 1, !"Debug Info Version", i32 3}
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!12 = !{!"clang version 3.5.0 "}
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!13 = !DILocalVariable(name: "i", line: 1, arg: 1, scope: !4, file: !5, type: !9)
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!14 = !DILocation(line: 1, scope: !4)
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!15 = !DILocation(line: 2, scope: !16)
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; CHECK: ![[ENTRY]] = !DILocation(line: 2, scope: ![[BLOCK:[0-9]+]])
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!16 = distinct !DILexicalBlock(line: 2, column: 0, file: !1, scope: !4)
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; CHECK: ![[BLOCK]] = distinct !DILexicalBlock(scope: ![[FOO]],{{.*}} line: 2)
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!17 = !DILocation(line: 3, scope: !4)
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