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 // Assume ld64 is new enough that the abs-ified FDE relocs may be used 76 // (actually, must, since otherwise the non-extern relocations we produce 77 // overwhelm ld64's tiny little mind and it fails). 78 DwarfFDESymbolsUseAbsDiff = true; 79 80 UseIntegratedAssembler = true; 81 } 82 83 X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple) 84 : X86MCAsmInfoDarwin(Triple) { 85 } 86 87 void X86ELFMCAsmInfo::anchor() { } 88 89 X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) { 90 bool is64Bit = T.getArch() == Triple::x86_64; 91 bool isX32 = T.getEnvironment() == Triple::GNUX32; 92 93 // For ELF, x86-64 pointer size depends on the ABI. 94 // For x86-64 without the x32 ABI, pointer size is 8. For x86 and for x86-64 95 // with the x32 ABI, pointer size remains the default 4. 96 PointerSize = (is64Bit && !isX32) ? 8 : 4; 97 98 // OTOH, stack slot size is always 8 for x86-64, even with the x32 ABI. 99 CalleeSaveStackSlotSize = is64Bit ? 8 : 4; 100 101 AssemblerDialect = AsmWriterFlavor; 102 103 TextAlignFillValue = 0x90; 104 105 // Debug Information 106 SupportsDebugInformation = true; 107 108 // Exceptions handling 109 ExceptionsType = ExceptionHandling::DwarfCFI; 110 111 // Always enable the integrated assembler by default. 112 // Clang also enabled it when the OS is Solaris but that is redundant here. 113 UseIntegratedAssembler = true; 114 } 115 116 const MCExpr * 117 X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym, 118 unsigned Encoding, 119 MCStreamer &Streamer) const { 120 MCContext &Context = Streamer.getContext(); 121 const MCExpr *Res = 122 MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context); 123 const MCExpr *Four = MCConstantExpr::create(4, Context); 124 return MCBinaryExpr::createAdd(Res, Four, Context); 125 } 126 127 void X86MCAsmInfoMicrosoft::anchor() { } 128 129 X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) { 130 if (Triple.getArch() == Triple::x86_64) { 131 PrivateGlobalPrefix = ".L"; 132 PrivateLabelPrefix = ".L"; 133 PointerSize = 8; 134 WinEHEncodingType = WinEH::EncodingType::Itanium; 135 } else { 136 // 32-bit X86 doesn't use CFI, so this isn't a real encoding type. It's just 137 // a place holder that the Windows EHStreamer looks for to suppress CFI 138 // output. In particular, usesWindowsCFI() returns false. 139 WinEHEncodingType = WinEH::EncodingType::X86; 140 } 141 142 ExceptionsType = ExceptionHandling::WinEH; 143 144 AssemblerDialect = AsmWriterFlavor; 145 146 TextAlignFillValue = 0x90; 147 148 AllowAtInName = true; 149 150 UseIntegratedAssembler = true; 151 } 152 153 void X86MCAsmInfoGNUCOFF::anchor() { } 154 155 X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) { 156 assert(Triple.isOSWindows() && "Windows is the only supported COFF target"); 157 if (Triple.getArch() == Triple::x86_64) { 158 PrivateGlobalPrefix = ".L"; 159 PrivateLabelPrefix = ".L"; 160 PointerSize = 8; 161 WinEHEncodingType = WinEH::EncodingType::Itanium; 162 ExceptionsType = ExceptionHandling::WinEH; 163 } else { 164 ExceptionsType = ExceptionHandling::DwarfCFI; 165 } 166 167 AssemblerDialect = AsmWriterFlavor; 168 169 TextAlignFillValue = 0x90; 170 171 UseIntegratedAssembler = true; 172 } 173
