Index: lib/CodeGen/AsmPrinter/DwarfDebug.cpp =================================================================== --- lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -811,14 +811,21 @@ /// Return true if the merge was successful. bool DebugLocEntry::MergeValues(const DebugLocEntry &Next) { if (Begin == Next.Begin) { - auto *Expr = cast_or_null(Values[0].Expression); - auto *NextExpr = cast_or_null(Next.Values[0].Expression); - if (Expr->isBitPiece() && NextExpr->isBitPiece() && - !piecesOverlap(Expr, NextExpr)) { - addValues(Next.Values); - End = Next.End; - return true; - } + auto *FirstExpr = cast_or_null(Values[0].Expression); + auto *FirstNextExpr = cast_or_null(Next.Values[0].Expression); + if (!FirstExpr->isBitPiece() || !FirstNextExpr->isBitPiece()) + return false; + + // We can only merge entries if none of the pieces overlap any others + for (auto &Value : Values) + for (auto &NextValue : Next.Values) + if (piecesOverlap(cast_or_null(Value.Expression), + cast_or_null(NextValue.Expression))) + return false; + + addValues(Next.Values); + End = Next.End; + return true; } return false; } Index: test/DebugInfo/X86/PR26148.ll =================================================================== --- /dev/null +++ test/DebugInfo/X86/PR26148.ll @@ -0,0 +1,102 @@ +; RUN: llc -filetype=obj -o - < %s | llvm-dwarfdump - | FileCheck %s +; +; Created using clang -g -O3 from: +; struct S0 { +; short f0; +; int f3; +; } a; +; void fn1(short p1) { +; struct S0 b, c = {3}; +; b.f3 = p1; +; a = b = c; +; } +; +; int main() { return 0; } +; +; This is similar to the bug in test/DebugInfo/ARM/PR26163.ll, except that there is an +; extra non-overlapping range first. Thus, we make sure that the backend actually looks +; at all expressions when determining whether to merge ranges, not just the first one. +; AS in 26163, we expect two ranges (as opposed to one), the first one being zero sized +; +; +; CHECK: 0x00000000: Beginning address offset: 0x0000000000000004 +; CHECK: Ending address offset: 0x0000000000000004 +; CHECK: Location description: 10 03 55 93 04 +; CHECK: Beginning address offset: 0x0000000000000004 +; CHECK: Ending address offset: 0x0000000000000014 +; CHECK: Location description: 10 03 10 00 + +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10.11.0" + +%struct.S0 = type { i16, i32 } + +@a = common global %struct.S0 zeroinitializer, align 4 + +declare void @llvm.dbg.declare(metadata, metadata, metadata) +declare void @llvm.dbg.value(metadata, i64, metadata, metadata) + +; The attributes are here to force the zero-sized range not to be at the start of +; the function, which has special interpretation in DWARF. The fact that this happens +; at all is probably an LLVM bug. +attributes #0 = { "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" } +define void @fn1(i16 signext %p1) #0 !dbg !4 { +entry: + tail call void @llvm.dbg.value(metadata i16 %p1, i64 0, metadata !9, metadata !26), !dbg !27 + tail call void @llvm.dbg.declare(metadata %struct.S0* undef, metadata !10, metadata !26), !dbg !28 + tail call void @llvm.dbg.declare(metadata %struct.S0* undef, metadata !16, metadata !26), !dbg !29 + tail call void @llvm.dbg.value(metadata i32 3, i64 0, metadata !16, metadata !30), !dbg !29 + tail call void @llvm.dbg.value(metadata i32 0, i64 0, metadata !16, metadata !31), !dbg !29 + tail call void @llvm.dbg.value(metadata i16 %p1, i64 0, metadata !10, metadata !32), !dbg !28 + tail call void @llvm.dbg.value(metadata i32 3, i64 0, metadata !10, metadata !30), !dbg !28 + tail call void @llvm.dbg.value(metadata i32 0, i64 0, metadata !10, metadata !31), !dbg !28 + store i32 3, i32* bitcast (%struct.S0* @a to i32*), align 4, !dbg !33 + store i32 0, i32* getelementptr inbounds (%struct.S0, %struct.S0* @a, i64 0, i32 1), align 4, !dbg !33 + ret void, !dbg !34 +} + +define i32 @main() !dbg !17 { +entry: + ret i32 0, !dbg !35 +} + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!22, !23, !24} +!llvm.ident = !{!25} + +!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 (https://github.com/llvm-mirror/clang 8f258397c5afd7a708bd95770c718e81d08fb11a) (https://github.com/llvm-mirror/llvm 18481855bdfa1b4a424f81be8525db002671348d)", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3, globals: !20) +!1 = !DIFile(filename: "small.c", directory: "/Users/kfischer/Projects/clangbug") +!2 = !{} +!3 = !{!4, !17} +!4 = distinct !DISubprogram(name: "fn1", scope: !1, file: !1, line: 5, type: !5, isLocal: false, isDefinition: true, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: true, variables: !8) +!5 = !DISubroutineType(types: !6) +!6 = !{null, !7} +!7 = !DIBasicType(name: "short", size: 16, align: 16, encoding: DW_ATE_signed) +!8 = !{!9, !10, !16} +!9 = !DILocalVariable(name: "p1", arg: 1, scope: !4, file: !1, line: 5, type: !7) +!10 = !DILocalVariable(name: "b", scope: !4, file: !1, line: 6, type: !11) +!11 = !DICompositeType(tag: DW_TAG_structure_type, name: "S0", file: !1, line: 1, size: 64, align: 32, elements: !12) +!12 = !{!13, !14} +!13 = !DIDerivedType(tag: DW_TAG_member, name: "f0", scope: !11, file: !1, line: 2, baseType: !7, size: 16, align: 16) +!14 = !DIDerivedType(tag: DW_TAG_member, name: "f3", scope: !11, file: !1, line: 3, baseType: !15, size: 32, align: 32, offset: 32) +!15 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed) +!16 = !DILocalVariable(name: "c", scope: !4, file: !1, line: 6, type: !11) +!17 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 11, type: !18, isLocal: false, isDefinition: true, scopeLine: 11, isOptimized: true, variables: !2) +!18 = !DISubroutineType(types: !19) +!19 = !{!15} +!20 = !{!21} +!21 = !DIGlobalVariable(name: "a", scope: !0, file: !1, line: 4, type: !11, isLocal: false, isDefinition: true, variable: %struct.S0* @a) +!22 = !{i32 2, !"Dwarf Version", i32 2} +!23 = !{i32 2, !"Debug Info Version", i32 3} +!24 = !{i32 1, !"PIC Level", i32 2} +!25 = !{!"clang version 3.9.0 (https://github.com/llvm-mirror/clang 8f258397c5afd7a708bd95770c718e81d08fb11a) (https://github.com/llvm-mirror/llvm 18481855bdfa1b4a424f81be8525db002671348d)"} +!26 = !DIExpression() +!27 = !DILocation(line: 5, column: 16, scope: !4) +!28 = !DILocation(line: 6, column: 13, scope: !4) +!29 = !DILocation(line: 6, column: 16, scope: !4) +!30 = !DIExpression(DW_OP_bit_piece, 0, 32) +!31 = !DIExpression(DW_OP_bit_piece, 32, 32) +!32 = !DIExpression(DW_OP_bit_piece, 32, 16) +!33 = !DILocation(line: 8, column: 9, scope: !4) +!34 = !DILocation(line: 9, column: 1, scope: !4) +!35 = !DILocation(line: 11, column: 14, scope: !17)