From 767b1be3900bdc693aa0ad3e554ba034845f67f7 Mon Sep 17 00:00:00 2001 From: Rafael Espindola Date: Sat, 4 Dec 2010 00:31:13 +0000 Subject: [PATCH] Next step: Only pad debug_line when the target is darwin. Add a FIXME to avoid doing that if the target is darwin10 or newer. This fixes *) Direct object emission was producing objects without the workaround on darwin9. *) Assembly printing was producing objects with the workaround on linux. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120866 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/MC/MCAsmInfo.h | 8 ++++++++ include/llvm/MC/MCDwarf.h | 3 +-- lib/MC/MCAsmInfo.cpp | 1 + lib/MC/MCAsmInfoDarwin.cpp | 3 +++ lib/MC/MCAsmStreamer.cpp | 3 +-- lib/MC/MCDwarf.cpp | 7 ++++--- test/MC/ELF/empty-dwarf-lines.s | 21 +++++++++++++++++++++ test/MC/MachO/empty-dwarf-lines.s | 25 +++++++++++++++++++++++++ 8 files changed, 64 insertions(+), 7 deletions(-) create mode 100644 test/MC/ELF/empty-dwarf-lines.s create mode 100644 test/MC/MachO/empty-dwarf-lines.s diff --git a/include/llvm/MC/MCAsmInfo.h b/include/llvm/MC/MCAsmInfo.h index 24620659440..d53318c6631 100644 --- a/include/llvm/MC/MCAsmInfo.h +++ b/include/llvm/MC/MCAsmInfo.h @@ -51,6 +51,11 @@ namespace llvm { /// emitted in Static relocation model. bool HasStaticCtorDtorReferenceInStaticMode; // Default is false. + /// LinkerRequiresNonEmptyDwarfLines - True if the linker has a bug and + /// requires that the debug_line section be of a minimum size. In practice + /// such a linker requires a non empty line sequence if a file is present. + bool LinkerRequiresNonEmptyDwarfLines; // Default to false. + /// MaxInstLength - This is the maximum possible length of an instruction, /// which is needed to compute the size of an inline asm. unsigned MaxInstLength; // Defaults to 4. @@ -322,6 +327,9 @@ namespace llvm { bool hasStaticCtorDtorReferenceInStaticMode() const { return HasStaticCtorDtorReferenceInStaticMode; } + bool getLinkerRequiresNonEmptyDwarfLines() const { + return LinkerRequiresNonEmptyDwarfLines; + } unsigned getMaxInstLength() const { return MaxInstLength; } diff --git a/include/llvm/MC/MCDwarf.h b/include/llvm/MC/MCDwarf.h index d528ac5f737..e9fc0cf8769 100644 --- a/include/llvm/MC/MCDwarf.h +++ b/include/llvm/MC/MCDwarf.h @@ -208,8 +208,7 @@ namespace llvm { // // This emits the Dwarf file and the line tables. // - static void Emit(MCStreamer *MCOS, const MCSection *DwarfLineSection, - const MCSection *TextSection = NULL); + static void Emit(MCStreamer *MCOS, const MCSection *DwarfLineSection); }; class MCDwarfLineAddr { diff --git a/lib/MC/MCAsmInfo.cpp b/lib/MC/MCAsmInfo.cpp index 37444c9c256..9cf4019e312 100644 --- a/lib/MC/MCAsmInfo.cpp +++ b/lib/MC/MCAsmInfo.cpp @@ -23,6 +23,7 @@ MCAsmInfo::MCAsmInfo() { HasMachoZeroFillDirective = false; HasMachoTBSSDirective = false; HasStaticCtorDtorReferenceInStaticMode = false; + LinkerRequiresNonEmptyDwarfLines = false; MaxInstLength = 4; PCSymbol = "$"; SeparatorChar = ';'; diff --git a/lib/MC/MCAsmInfoDarwin.cpp b/lib/MC/MCAsmInfoDarwin.cpp index fd155135df0..1147f02a596 100644 --- a/lib/MC/MCAsmInfoDarwin.cpp +++ b/lib/MC/MCAsmInfoDarwin.cpp @@ -37,6 +37,9 @@ MCAsmInfoDarwin::MCAsmInfoDarwin() { HasMachoZeroFillDirective = true; // Uses .zerofill HasMachoTBSSDirective = true; // Uses .tbss HasStaticCtorDtorReferenceInStaticMode = true; + + // FIXME: Darwin 10 and newer don't need this. + LinkerRequiresNonEmptyDwarfLines = true; HiddenVisibilityAttr = MCSA_PrivateExtern; // Doesn't support protected visibility. diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp index 7189a90406e..40a234ea85f 100644 --- a/lib/MC/MCAsmStreamer.cpp +++ b/lib/MC/MCAsmStreamer.cpp @@ -896,8 +896,7 @@ void MCAsmStreamer::EmitRawText(StringRef String) { void MCAsmStreamer::Finish() { // Dump out the dwarf file & directory tables and line tables. if (getContext().hasDwarfFiles() && TLOF) - MCDwarfFileTable::Emit(this, TLOF->getDwarfLineSection(), - TLOF->getTextSection()); + MCDwarfFileTable::Emit(this, TLOF->getDwarfLineSection()); } MCStreamer *llvm::createAsmStreamer(MCContext &Context, diff --git a/lib/MC/MCDwarf.cpp b/lib/MC/MCDwarf.cpp index 194c324ab6c..a33b0c596ba 100644 --- a/lib/MC/MCDwarf.cpp +++ b/lib/MC/MCDwarf.cpp @@ -7,6 +7,7 @@ // //===----------------------------------------------------------------------===// +#include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCDwarf.h" #include "llvm/MC/MCAssembler.h" #include "llvm/MC/MCStreamer.h" @@ -198,8 +199,7 @@ static inline void EmitDwarfLineTable(MCStreamer *MCOS, // This emits the Dwarf file and the line tables. // void MCDwarfFileTable::Emit(MCStreamer *MCOS, - const MCSection *DwarfLineSection, - const MCSection *TextSection) { + const MCSection *DwarfLineSection) { // Switch to the section where the table will be emitted into. MCOS->SwitchSection(DwarfLineSection); @@ -296,7 +296,8 @@ void MCDwarfFileTable::Emit(MCStreamer *MCOS, delete Line; } - if (TextSection && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) { + if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines() + && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) { // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures // it requires: // total_length >= prologue_length + 10 diff --git a/test/MC/ELF/empty-dwarf-lines.s b/test/MC/ELF/empty-dwarf-lines.s new file mode 100644 index 00000000000..81d98711e9d --- /dev/null +++ b/test/MC/ELF/empty-dwarf-lines.s @@ -0,0 +1,21 @@ +// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | elf-dump | FileCheck %s + +// Test that the dwarf debug_line section contains no line directives. + + .file 1 "test.c" + .globl c +c: + .asciz "hi\n" + +// CHECK: # Section 0x00000004 +// CHECK-NEXT: (('sh_name', 0x00000012) # '.debug_line' +// CHECK-NEXT: ('sh_type', 0x00000000) +// CHECK-NEXT: ('sh_flags', 0x00000000) +// CHECK-NEXT: ('sh_addr', 0x00000000) +// CHECK-NEXT: ('sh_offset', 0x00000044) +// CHECK-NEXT: ('sh_size', 0x00000027) +// CHECK-NEXT: ('sh_link', 0x00000000) +// CHECK-NEXT: ('sh_info', 0x00000000) +// CHECK-NEXT: ('sh_addralign', 0x00000001) +// CHECK-NEXT: ('sh_entsize', 0x00000000) +// CHECK-NEXT: ), diff --git a/test/MC/MachO/empty-dwarf-lines.s b/test/MC/MachO/empty-dwarf-lines.s new file mode 100644 index 00000000000..29ef218fddc --- /dev/null +++ b/test/MC/MachO/empty-dwarf-lines.s @@ -0,0 +1,25 @@ +// RUN: llvm-mc -triple x86_64-apple-darwin9 %s -filetype=obj -o - | macho-dump | FileCheck %s + +// This tests that when producing files for darwin9 or older we make sure +// that debug_line sections are of a minimum size to avoid the linker bug +// described in PR8715. + + .section __DATA,__data + .file 1 "test.c" + .globl _c ## @c +_c: + .asciz "hi\n" + +// CHECK: (('section_name', '__debug_line\x00\x00\x00\x00') +// CHECK-NEXT: ('segment_name', '__DWARF\x00\x00\x00\x00\x00\x00\x00\x00\x00') +// CHECK-NEXT: ('address', 4) +// CHECK-NEXT: ('size', 44) +// CHECK-NEXT: ('offset', 452) +// CHECK-NEXT: ('alignment', 0) +// CHECK-NEXT: ('reloc_offset', 496) +// CHECK-NEXT: ('num_reloc', 4) +// CHECK-NEXT: ('flags', 0x2000000) +// CHECK-NEXT: ('reserved1', 0) +// CHECK-NEXT: ('reserved2', 0) +// CHECK-NEXT: ('reserved3', 0) +// CHECK-NEXT: ),