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 = nullptr; // 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 63 SupportsDebugInformation = true; 64 UseDataRegionDirectives = MarkedJTDataRegions; 65 66 // Exceptions handling 67 ExceptionsType = ExceptionHandling::DwarfCFI; 68 69 // old assembler lacks some directives 70 // FIXME: this should really be a check on the assembler characteristics 71 // rather than OS version 72 if (T.isMacOSX() && T.isMacOSXVersionLT(10, 6)) 73 HasWeakDefCanBeHiddenDirective = false; 74 75 // FIXME: this should not depend on the target OS version, but on the ld64 76 // version in use. From at least >= ld64-97.17 (Xcode 3.2.6) the abs-ified 77 // FDE relocs may be used. We also use them for the ios simulator. 78 DwarfFDESymbolsUseAbsDiff = (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6)) 79 || T.isiOS(); 80 81 UseIntegratedAssembler = true; 82 } 83 84 X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple) 85 : X86MCAsmInfoDarwin(Triple) { 86 } 87 88 void X86ELFMCAsmInfo::anchor() { } 89 90 X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) { 91 bool is64Bit = T.getArch() == Triple::x86_64; 92 bool isX32 = T.getEnvironment() == Triple::GNUX32; 93 94 // For ELF, x86-64 pointer size depends on the ABI. 95 // For x86-64 without the x32 ABI, pointer size is 8. For x86 and for x86-64 96 // with the x32 ABI, pointer size remains the default 4. 97 PointerSize = (is64Bit && !isX32) ? 8 : 4; 98 99 // OTOH, stack slot size is always 8 for x86-64, even with the x32 ABI. 100 CalleeSaveStackSlotSize = is64Bit ? 8 : 4; 101 102 AssemblerDialect = AsmWriterFlavor; 103 104 TextAlignFillValue = 0x90; 105 106 // Set up DWARF directives 107 HasLEB128 = true; // Target asm supports leb128 directives (little-endian) 108 109 // Debug Information 110 SupportsDebugInformation = true; 111 112 // Exceptions handling 113 ExceptionsType = ExceptionHandling::DwarfCFI; 114 115 // OpenBSD and Bitrig have buggy support for .quad in 32-bit mode, just split 116 // into two .words. 117 if ((T.getOS() == Triple::OpenBSD || T.getOS() == Triple::Bitrig) && 118 T.getArch() == Triple::x86) 119 Data64bitsDirective = nullptr; 120 121 // Always enable the integrated assembler by default. 122 // Clang also enabled it when the OS is Solaris but that is redundant here. 123 UseIntegratedAssembler = true; 124 } 125 126 const MCExpr * 127 X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym, 128 unsigned Encoding, 129 MCStreamer &Streamer) const { 130 MCContext &Context = Streamer.getContext(); 131 const MCExpr *Res = 132 MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context); 133 const MCExpr *Four = MCConstantExpr::Create(4, Context); 134 return MCBinaryExpr::CreateAdd(Res, Four, Context); 135 } 136 137 const MCSection *X86ELFMCAsmInfo:: 138 getNonexecutableStackSection(MCContext &Ctx) const { 139 return Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS, 140 0, SectionKind::getMetadata()); 141 } 142 143 void X86MCAsmInfoMicrosoft::anchor() { } 144 145 X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) { 146 if (Triple.getArch() == Triple::x86_64) { 147 PrivateGlobalPrefix = ".L"; 148 PointerSize = 8; 149 ExceptionsType = ExceptionHandling::WinEH; 150 } 151 152 AssemblerDialect = AsmWriterFlavor; 153 154 TextAlignFillValue = 0x90; 155 156 AllowAtInName = true; 157 158 UseIntegratedAssembler = true; 159 } 160 161 void X86MCAsmInfoGNUCOFF::anchor() { } 162 163 X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) { 164 assert(Triple.isOSWindows() && "Windows is the only supported COFF target"); 165 if (Triple.getArch() == Triple::x86_64) { 166 PrivateGlobalPrefix = ".L"; 167 PointerSize = 8; 168 ExceptionsType = ExceptionHandling::WinEH; 169 } else { 170 ExceptionsType = ExceptionHandling::DwarfCFI; 171 } 172 173 AssemblerDialect = AsmWriterFlavor; 174 175 TextAlignFillValue = 0x90; 176 177 UseIntegratedAssembler = true; 178 } 179
