1 //===-- X86MCAsmInfo.cpp - X86 asm properties -----------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains the declarations of the X86MCAsmInfo properties. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "X86MCAsmInfo.h" 14 #include "llvm/ADT/Triple.h" 15 #include "llvm/MC/MCExpr.h" 16 #include "llvm/MC/MCStreamer.h" 17 #include "llvm/Support/CommandLine.h" 18 using namespace llvm; 19 20 enum AsmWriterFlavorTy { 21 // Note: This numbering has to match the GCC assembler dialects for inline 22 // asm alternatives to work right. 23 ATT = 0, Intel = 1 24 }; 25 26 static cl::opt<AsmWriterFlavorTy> AsmWriterFlavor( 27 "x86-asm-syntax", cl::init(ATT), cl::Hidden, 28 cl::desc("Choose style of code to emit from X86 backend:"), 29 cl::values(clEnumValN(ATT, "att", "Emit AT&T-style assembly"), 30 clEnumValN(Intel, "intel", "Emit Intel-style assembly"))); 31 32 static cl::opt<bool> 33 MarkedJTDataRegions("mark-data-regions", cl::init(true), 34 cl::desc("Mark code section jump table data regions."), 35 cl::Hidden); 36 37 void X86MCAsmInfoDarwin::anchor() { } 38 39 X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &T) { 40 bool is64Bit = T.getArch() == Triple::x86_64; 41 if (is64Bit) 42 CodePointerSize = CalleeSaveStackSlotSize = 8; 43 44 AssemblerDialect = AsmWriterFlavor; 45 46 TextAlignFillValue = 0x90; 47 48 if (!is64Bit) 49 Data64bitsDirective = nullptr; // we can't emit a 64-bit unit 50 51 // Use ## as a comment string so that .s files generated by llvm can go 52 // through the GCC preprocessor without causing an error. This is needed 53 // because "clang foo.s" runs the C preprocessor, which is usually reserved 54 // for .S files on other systems. Perhaps this is because the file system 55 // wasn't always case preserving or something. 56 CommentString = "##"; 57 58 SupportsDebugInformation = true; 59 UseDataRegionDirectives = MarkedJTDataRegions; 60 61 // Exceptions handling 62 ExceptionsType = ExceptionHandling::DwarfCFI; 63 64 // old assembler lacks some directives 65 // FIXME: this should really be a check on the assembler characteristics 66 // rather than OS version 67 if (T.isMacOSX() && T.isMacOSXVersionLT(10, 6)) 68 HasWeakDefCanBeHiddenDirective = false; 69 70 // Assume ld64 is new enough that the abs-ified FDE relocs may be used 71 // (actually, must, since otherwise the non-extern relocations we produce 72 // overwhelm ld64's tiny little mind and it fails). 73 DwarfFDESymbolsUseAbsDiff = true; 74 75 UseIntegratedAssembler = true; 76 } 77 78 X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple) 79 : X86MCAsmInfoDarwin(Triple) { 80 } 81 82 void X86ELFMCAsmInfo::anchor() { } 83 84 X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) { 85 bool is64Bit = T.getArch() == Triple::x86_64; 86 bool isX32 = T.getEnvironment() == Triple::GNUX32; 87 88 // For ELF, x86-64 pointer size depends on the ABI. 89 // For x86-64 without the x32 ABI, pointer size is 8. For x86 and for x86-64 90 // with the x32 ABI, pointer size remains the default 4. 91 CodePointerSize = (is64Bit && !isX32) ? 8 : 4; 92 93 // OTOH, stack slot size is always 8 for x86-64, even with the x32 ABI. 94 CalleeSaveStackSlotSize = is64Bit ? 8 : 4; 95 96 AssemblerDialect = AsmWriterFlavor; 97 98 TextAlignFillValue = 0x90; 99 100 // Debug Information 101 SupportsDebugInformation = true; 102 103 // Exceptions handling 104 ExceptionsType = ExceptionHandling::DwarfCFI; 105 106 // Always enable the integrated assembler by default. 107 // Clang also enabled it when the OS is Solaris but that is redundant here. 108 UseIntegratedAssembler = true; 109 } 110 111 const MCExpr * 112 X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym, 113 unsigned Encoding, 114 MCStreamer &Streamer) const { 115 MCContext &Context = Streamer.getContext(); 116 const MCExpr *Res = 117 MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context); 118 const MCExpr *Four = MCConstantExpr::create(4, Context); 119 return MCBinaryExpr::createAdd(Res, Four, Context); 120 } 121 122 void X86MCAsmInfoMicrosoft::anchor() { } 123 124 X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) { 125 if (Triple.getArch() == Triple::x86_64) { 126 PrivateGlobalPrefix = ".L"; 127 PrivateLabelPrefix = ".L"; 128 CodePointerSize = 8; 129 WinEHEncodingType = WinEH::EncodingType::Itanium; 130 } else { 131 // 32-bit X86 doesn't use CFI, so this isn't a real encoding type. It's just 132 // a place holder that the Windows EHStreamer looks for to suppress CFI 133 // output. In particular, usesWindowsCFI() returns false. 134 WinEHEncodingType = WinEH::EncodingType::X86; 135 } 136 137 ExceptionsType = ExceptionHandling::WinEH; 138 139 AssemblerDialect = AsmWriterFlavor; 140 141 TextAlignFillValue = 0x90; 142 143 AllowAtInName = true; 144 145 UseIntegratedAssembler = true; 146 } 147 148 void X86MCAsmInfoGNUCOFF::anchor() { } 149 150 X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) { 151 assert(Triple.isOSWindows() && "Windows is the only supported COFF target"); 152 if (Triple.getArch() == Triple::x86_64) { 153 PrivateGlobalPrefix = ".L"; 154 PrivateLabelPrefix = ".L"; 155 CodePointerSize = 8; 156 WinEHEncodingType = WinEH::EncodingType::Itanium; 157 ExceptionsType = ExceptionHandling::WinEH; 158 } else { 159 ExceptionsType = ExceptionHandling::DwarfCFI; 160 } 161 162 AssemblerDialect = AsmWriterFlavor; 163 164 TextAlignFillValue = 0x90; 165 166 UseIntegratedAssembler = true; 167 } 168