1 //===-- X86MCAsmInfo.cpp - X86 asm properties -----------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file contains the declarations of the X86MCAsmInfo properties. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "X86MCAsmInfo.h" 15 #include "llvm/ADT/Triple.h" 16 #include "llvm/MC/MCContext.h" 17 #include "llvm/MC/MCExpr.h" 18 #include "llvm/MC/MCSectionELF.h" 19 #include "llvm/MC/MCStreamer.h" 20 #include "llvm/Support/CommandLine.h" 21 #include "llvm/Support/ELF.h" 22 using namespace llvm; 23 24 enum AsmWriterFlavorTy { 25 // Note: This numbering has to match the GCC assembler dialects for inline 26 // asm alternatives to work right. 27 ATT = 0, Intel = 1 28 }; 29 30 static cl::opt<AsmWriterFlavorTy> 31 AsmWriterFlavor("x86-asm-syntax", cl::init(ATT), 32 cl::desc("Choose style of code to emit from X86 backend:"), 33 cl::values(clEnumValN(ATT, "att", "Emit AT&T-style assembly"), 34 clEnumValN(Intel, "intel", "Emit Intel-style assembly"), 35 clEnumValEnd)); 36 37 static cl::opt<bool> 38 MarkedJTDataRegions("mark-data-regions", cl::init(false), 39 cl::desc("Mark code section jump table data regions."), 40 cl::Hidden); 41 42 void X86MCAsmInfoDarwin::anchor() { } 43 44 X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &T) { 45 bool is64Bit = T.getArch() == Triple::x86_64; 46 if (is64Bit) 47 PointerSize = CalleeSaveStackSlotSize = 8; 48 49 AssemblerDialect = AsmWriterFlavor; 50 51 TextAlignFillValue = 0x90; 52 53 if (!is64Bit) 54 Data64bitsDirective = 0; // we can't emit a 64-bit unit 55 56 // Use ## as a comment string so that .s files generated by llvm can go 57 // through the GCC preprocessor without causing an error. This is needed 58 // because "clang foo.s" runs the C preprocessor, which is usually reserved 59 // for .S files on other systems. Perhaps this is because the file system 60 // wasn't always case preserving or something. 61 CommentString = "##"; 62 PCSymbol = "."; 63 64 SupportsDebugInformation = true; 65 DwarfUsesInlineInfoSection = true; 66 UseDataRegionDirectives = MarkedJTDataRegions; 67 68 // Exceptions handling 69 ExceptionsType = ExceptionHandling::DwarfCFI; 70 } 71 72 X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple) 73 : X86MCAsmInfoDarwin(Triple) { 74 } 75 76 void X86ELFMCAsmInfo::anchor() { } 77 78 X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) { 79 bool is64Bit = T.getArch() == Triple::x86_64; 80 bool isX32 = T.getEnvironment() == Triple::GNUX32; 81 82 // For ELF, x86-64 pointer size depends on the ABI. 83 // For x86-64 without the x32 ABI, pointer size is 8. For x86 and for x86-64 84 // with the x32 ABI, pointer size remains the default 4. 85 PointerSize = (is64Bit && !isX32) ? 8 : 4; 86 87 // OTOH, stack slot size is always 8 for x86-64, even with the x32 ABI. 88 CalleeSaveStackSlotSize = is64Bit ? 8 : 4; 89 90 AssemblerDialect = AsmWriterFlavor; 91 92 TextAlignFillValue = 0x90; 93 94 PrivateGlobalPrefix = ".L"; 95 WeakRefDirective = "\t.weak\t"; 96 PCSymbol = "."; 97 98 // Set up DWARF directives 99 HasLEB128 = true; // Target asm supports leb128 directives (little-endian) 100 101 // Debug Information 102 SupportsDebugInformation = true; 103 104 // Exceptions handling 105 ExceptionsType = ExceptionHandling::DwarfCFI; 106 107 // OpenBSD and Bitrig have buggy support for .quad in 32-bit mode, just split 108 // into two .words. 109 if ((T.getOS() == Triple::OpenBSD || T.getOS() == Triple::Bitrig) && 110 T.getArch() == Triple::x86) 111 Data64bitsDirective = 0; 112 } 113 114 const MCExpr * 115 X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym, 116 unsigned Encoding, 117 MCStreamer &Streamer) const { 118 MCContext &Context = Streamer.getContext(); 119 const MCExpr *Res = 120 MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context); 121 const MCExpr *Four = MCConstantExpr::Create(4, Context); 122 return MCBinaryExpr::CreateAdd(Res, Four, Context); 123 } 124 125 const MCSection *X86ELFMCAsmInfo:: 126 getNonexecutableStackSection(MCContext &Ctx) const { 127 return Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS, 128 0, SectionKind::getMetadata()); 129 } 130 131 void X86MCAsmInfoMicrosoft::anchor() { } 132 133 X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) { 134 if (Triple.getArch() == Triple::x86_64) { 135 GlobalPrefix = ""; 136 PrivateGlobalPrefix = ".L"; 137 } 138 139 AssemblerDialect = AsmWriterFlavor; 140 141 TextAlignFillValue = 0x90; 142 } 143 144 void X86MCAsmInfoGNUCOFF::anchor() { } 145 146 X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) { 147 if (Triple.getArch() == Triple::x86_64) { 148 GlobalPrefix = ""; 149 PrivateGlobalPrefix = ".L"; 150 } 151 152 AssemblerDialect = AsmWriterFlavor; 153 154 TextAlignFillValue = 0x90; 155 156 // Exceptions handling 157 ExceptionsType = ExceptionHandling::DwarfCFI; 158 } 159
