Index: llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.h =================================================================== --- llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.h +++ llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.h @@ -38,10 +38,12 @@ MachineModuleInfo *MMI; /// Previous instruction's location information. This is used to - /// determine label location to indicate scope boundries in dwarf - /// debug info. + /// determine label location to indicate scope boundaries in debug info. + /// We track the previous instruction's source location (if not line 0), + /// whether it was a label, and its parent BB. DebugLoc PrevInstLoc; MCSymbol *PrevLabel = nullptr; + const MachineBasicBlock *PrevInstBB = nullptr; /// This location indicates end of function prologue and beginning of /// function body. Index: llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp =================================================================== --- llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp +++ llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp @@ -201,8 +201,10 @@ assert(CurMI != nullptr); // Don't create a new label after DBG_VALUE instructions. // They don't generate code. - if (!CurMI->isDebugValue()) + if (!CurMI->isDebugValue()) { PrevLabel = nullptr; + PrevInstBB = CurMI->getParent(); + } DenseMap::iterator I = LabelsAfterInsn.find(CurMI); Index: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp =================================================================== --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -1010,31 +1010,70 @@ if (MI->isDebugValue()) return; const DebugLoc &DL = MI->getDebugLoc(); - if (DL == PrevInstLoc) + // When we emit a line-0 record, we don't update PrevInstLoc; so look at + // the last line number actually emitted, to see if it was line 0. + unsigned LastAsmLine = + Asm->OutStreamer->getContext().getCurrentDwarfLoc().getLine(); + + if (DL == PrevInstLoc) { + // If we have an ongoing unspecified location, nothing to do here. + if (!DL) + return; + // We have an explicit location, same as the previous location. + // But we might be coming back to it after a line 0 record. + if (LastAsmLine == 0 && DL.getLine() != 0) { + // Reinstate the source location but not marked as a statement. + const MDNode *Scope = DL.getScope(); + recordSourceLine(DL.getLine(), DL.getCol(), Scope, /*Flags=*/0); + } return; + } if (!DL) { // We have an unspecified location, which might want to be line 0. - if (UnknownLocations) { - PrevInstLoc = DL; - recordSourceLine(0, 0, nullptr, 0); + // If we have already emitted a line-0 record, don't repeat it. + if (LastAsmLine == 0) + return; + // See if we have a reason to emit a line-0 record now. + // Reasons to emit a line-0 record include: + // - User asked for it (UnknownLocations). + // - Instruction has a label, so it's referenced from somewhere else, + // possibly debug information; we want it to have a source location. + // - Instruction is at the top of a block; we don't want to inherit the + // location from the physically previous (maybe unrelated) block. + if (UnknownLocations || PrevLabel || + (PrevInstBB && PrevInstBB != MI->getParent())) { + // Preserve the file number, if we can, to save space in the line table. + // Do not update PrevInstLoc, it remembers the last non-0 line. + // FIXME: Also preserve the column number, to save more space? + const MDNode *Scope = PrevInstLoc ? PrevInstLoc.getScope() : nullptr; + recordSourceLine(0, 0, Scope, 0); } return; } - // We have a new, explicit location. + // We have an explicit location, different from the previous location. + // Don't repeat a line-0 record, but otherwise emit the new location. + // (The new location might be an explicit line 0, which we do emit.) + if (DL.getLine() == 0 && LastAsmLine == 0) + return; unsigned Flags = 0; - PrevInstLoc = DL; if (DL == PrologEndLoc) { Flags |= DWARF2_FLAG_PROLOGUE_END | DWARF2_FLAG_IS_STMT; PrologEndLoc = DebugLoc(); } - if (DL.getLine() != - Asm->OutStreamer->getContext().getCurrentDwarfLoc().getLine()) + // If the line changed, we call that a new statement; unless we went to + // line 0 and came back, in which case it is not a new statement. + unsigned OldLine = PrevInstLoc ? PrevInstLoc.getLine() : LastAsmLine; + if (DL.getLine() && DL.getLine() != OldLine) Flags |= DWARF2_FLAG_IS_STMT; const MDNode *Scope = DL.getScope(); recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags); + + // If we're not at line 0, remember this location. + if (DL.getLine()) + PrevInstLoc = DL; } static DebugLoc findPrologueEndLoc(const MachineFunction *MF) { Index: llvm/trunk/test/CodeGen/X86/stack-protector.ll =================================================================== --- llvm/trunk/test/CodeGen/X86/stack-protector.ll +++ llvm/trunk/test/CodeGen/X86/stack-protector.ll @@ -3888,23 +3888,27 @@ define void @test32() #1 !dbg !7 { entry: ; LINUX-I386-LABEL: test32: -; LINUX-I386: .loc 1 0 0 prologue_end +; LINUX-I386: .loc 1 4 2 prologue_end +; LINUX-I386: .loc 1 0 0 ; LINUX-I386-NEXT: calll __stack_chk_fail ; LINUX-X64-LABEL: test32: -; LINUX-X64: .loc 1 0 0 prologue_end +; LINUX-X64: .loc 1 4 2 prologue_end +; LINUX-X64: .loc 1 0 0 ; LINUX-X64-NEXT: callq __stack_chk_fail ; LINUX-KERNEL-X64-LABEL: test32: -; LINUX-KERNEL-X64: .loc 1 0 0 prologue_end +; LINUX-KERNEL-X64: .loc 1 4 2 prologue_end +; LINUX-KERNEL-X64: .loc 1 0 0 ; LINUX-KERNEL-X64-NEXT: callq __stack_chk_fail ; OPENBSD-AMD64-LABEL: test32: -; OPENBSD-AMD64: .loc 1 0 0 prologue_end +; OPENBSD-AMD64: .loc 1 4 2 prologue_end +; OPENBSD-AMD64: .loc 1 0 0 ; OPENBSD-AMD64-NEXT: movl ; OPENBSD-AMD64-NEXT: callq __stack_smash_handler %0 = alloca [5 x i8], align 1 - ret void + ret void, !dbg !9 } declare double @testi_aux() @@ -3940,3 +3944,4 @@ !6 = distinct !DISubprogram(name: "__stack_chk_fail", scope: !1, type: !8, unit: !0) !7 = distinct !DISubprogram(name: "test32", scope: !1, type: !8, unit: !0) !8 = !DISubroutineType(types: !2) +!9 = !DILocation(line: 4, column: 2, scope: !7) Index: llvm/trunk/test/DebugInfo/AArch64/line-header.ll =================================================================== --- llvm/trunk/test/DebugInfo/AArch64/line-header.ll +++ llvm/trunk/test/DebugInfo/AArch64/line-header.ll @@ -3,4 +3,4 @@ ; check line table length is correctly calculated for both big and little endian CHECK-LABEL: .debug_line contents: -CHECK: total_length: 0x0000003c +CHECK: total_length: 0x0000003e Index: llvm/trunk/test/DebugInfo/X86/dwarf-no-source-loc.ll =================================================================== --- llvm/trunk/test/DebugInfo/X86/dwarf-no-source-loc.ll +++ llvm/trunk/test/DebugInfo/X86/dwarf-no-source-loc.ll @@ -0,0 +1,74 @@ +; Verify "no source location" directives appear in appropriate places. +; RUN: llc %s -o - | FileCheck %s + +; Generated from this .cpp targeting linux using -g +; and then removed function attributes as clutter. +; +; void bar(int *); +; void baz(int *); +; # 5 "no-source-loc.cpp" +; void foo(int x) { +; int z; +; if (x) +; # 20 "include.h" +; bar(&z); +; # 10 "no-source-loc.cpp" +; baz(&z); +; } + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +; Function Attrs: uwtable +define void @_Z3fooi(i32 %x) !dbg !6 { +entry: + %x.addr = alloca i32, align 4 + %z = alloca i32, align 4 + store i32 %x, i32* %x.addr, align 4 + %0 = load i32, i32* %x.addr, align 4, !dbg !8 + %tobool = icmp ne i32 %0, 0, !dbg !8 + br i1 %tobool, label %if.then, label %if.end, !dbg !8 + +if.then: ; preds = %entry + call void @_Z3barPi(i32* %z), !dbg !9 + br label %if.end, !dbg !9 + +if.end: ; preds = %if.then, %entry + call void @_Z3bazPi(i32* %z), !dbg !12 + ret void, !dbg !14 +} + +; CHECK: .loc 1 7 7 +; CHECK-NOT: .loc +; CHECK: .loc 1 0 0 is_stmt 0 +; CHECK-NOT: .loc +; CHECK: .loc 2 20 5 is_stmt 1 +; CHECK: .LBB0_2: +; CHECK-NEXT: .loc 2 0 0 is_stmt 0 +; CHECK-NOT: .loc +; CHECK: .loc 1 10 3 is_stmt 1 + + +declare void @_Z3barPi(i32*) + +declare void @_Z3bazPi(i32*) + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!3, !4} +!llvm.ident = !{!5} + +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 4.0.0 (trunk 278782)", isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2) +!1 = !DIFile(filename: "no-source-loc.cpp", directory: "/tests") +!2 = !{} +!3 = !{i32 2, !"Dwarf Version", i32 4} +!4 = !{i32 2, !"Debug Info Version", i32 3} +!5 = !{!"clang version 4.0.0 (trunk 278782)"} +!6 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 5, type: !7, isLocal: false, isDefinition: true, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2) +!7 = !DISubroutineType(types: !2) +!8 = !DILocation(line: 7, column: 7, scope: !6) +!9 = !DILocation(line: 20, column: 5, scope: !10) +!10 = !DILexicalBlockFile(scope: !6, file: !11, discriminator: 0) +!11 = !DIFile(filename: "include.h", directory: "/tests") +!12 = !DILocation(line: 10, column: 3, scope: !13) +!13 = !DILexicalBlockFile(scope: !6, file: !1, discriminator: 0) +!14 = !DILocation(line: 11, column: 1, scope: !13)