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 36 static cl::opt<bool> 37 MarkedJTDataRegions("mark-data-regions", cl::init(true), 38 cl::desc("Mark code section jump table data regions."), 39 cl::Hidden); 40 41 void X86MCAsmInfoDarwin::anchor() { } 42 43 X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &T) { 44 bool is64Bit = T.getArch() == Triple::x86_64; 45 if (is64Bit) 46 PointerSize = CalleeSaveStackSlotSize = 8; 47 48 AssemblerDialect = AsmWriterFlavor; 49 50 TextAlignFillValue = 0x90; 51 52 if (!is64Bit) 53 Data64bitsDirective = nullptr; // we can't emit a 64-bit unit 54 55 // Use ## as a comment string so that .s files generated by llvm can go 56 // through the GCC preprocessor without causing an error. This is needed 57 // because "clang foo.s" runs the C preprocessor, which is usually reserved 58 // for .S files on other systems. Perhaps this is because the file system 59 // wasn't always case preserving or something. 60 CommentString = "##"; 61 62 SupportsDebugInformation = true; 63 UseDataRegionDirectives = MarkedJTDataRegions; 64 65 // Exceptions handling 66 ExceptionsType = ExceptionHandling::DwarfCFI; 67 68 // old assembler lacks some directives 69 // FIXME: this should really be a check on the assembler characteristics 70 // rather than OS version 71 if (T.isMacOSX() && T.isMacOSXVersionLT(10, 6)) 72 HasWeakDefCanBeHiddenDirective = false; 73 74 // Assume ld64 is new enough that the abs-ified FDE relocs may be used 75 // (actually, must, since otherwise the non-extern relocations we produce 76 // overwhelm ld64's tiny little mind and it fails). 77 DwarfFDESymbolsUseAbsDiff = true; 78 79 UseIntegratedAssembler = true; 80 } 81 82 X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple) 83 : X86MCAsmInfoDarwin(Triple) { 84 } 85 86 void X86ELFMCAsmInfo::anchor() { } 87 88 X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) { 89 bool is64Bit = T.getArch() == Triple::x86_64; 90 bool isX32 = T.getEnvironment() == Triple::GNUX32; 91 92 // For ELF, x86-64 pointer size depends on the ABI. 93 // For x86-64 without the x32 ABI, pointer size is 8. For x86 and for x86-64 94 // with the x32 ABI, pointer size remains the default 4. 95 PointerSize = (is64Bit && !isX32) ? 8 : 4; 96 97 // OTOH, stack slot size is always 8 for x86-64, even with the x32 ABI. 98 CalleeSaveStackSlotSize = is64Bit ? 8 : 4; 99 100 AssemblerDialect = AsmWriterFlavor; 101 102 TextAlignFillValue = 0x90; 103 104 // Debug Information 105 SupportsDebugInformation = true; 106 107 // Exceptions handling 108 ExceptionsType = ExceptionHandling::DwarfCFI; 109 110 // Always enable the integrated assembler by default. 111 // Clang also enabled it when the OS is Solaris but that is redundant here. 112 UseIntegratedAssembler = true; 113 } 114 115 const MCExpr * 116 X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym, 117 unsigned Encoding, 118 MCStreamer &Streamer) const { 119 MCContext &Context = Streamer.getContext(); 120 const MCExpr *Res = 121 MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context); 122 const MCExpr *Four = MCConstantExpr::create(4, Context); 123 return MCBinaryExpr::createAdd(Res, Four, Context); 124 } 125 126 void X86MCAsmInfoMicrosoft::anchor() { } 127 128 X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) { 129 if (Triple.getArch() == Triple::x86_64) { 130 PrivateGlobalPrefix = ".L"; 131 PrivateLabelPrefix = ".L"; 132 PointerSize = 8; 133 WinEHEncodingType = WinEH::EncodingType::Itanium; 134 } else { 135 // 32-bit X86 doesn't use CFI, so this isn't a real encoding type. It's just 136 // a place holder that the Windows EHStreamer looks for to suppress CFI 137 // output. In particular, usesWindowsCFI() returns false. 138 WinEHEncodingType = WinEH::EncodingType::X86; 139 } 140 141 ExceptionsType = ExceptionHandling::WinEH; 142 143 AssemblerDialect = AsmWriterFlavor; 144 145 TextAlignFillValue = 0x90; 146 147 AllowAtInName = true; 148 149 UseIntegratedAssembler = true; 150 } 151 152 void X86MCAsmInfoGNUCOFF::anchor() { } 153 154 X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) { 155 assert(Triple.isOSWindows() && "Windows is the only supported COFF target"); 156 if (Triple.getArch() == Triple::x86_64) { 157 PrivateGlobalPrefix = ".L"; 158 PrivateLabelPrefix = ".L"; 159 PointerSize = 8; 160 WinEHEncodingType = WinEH::EncodingType::Itanium; 161 ExceptionsType = ExceptionHandling::WinEH; 162 } else { 163 ExceptionsType = ExceptionHandling::DwarfCFI; 164 } 165 166 AssemblerDialect = AsmWriterFlavor; 167 168 TextAlignFillValue = 0x90; 169 170 UseIntegratedAssembler = true; 171 } 172