X86MCAsmInfo.cpp revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f
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" 22using namespace llvm; 23 24enum 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 30static cl::opt<AsmWriterFlavorTy> 31AsmWriterFlavor("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 37static cl::opt<bool> 38MarkedJTDataRegions("mark-data-regions", cl::init(false), 39 cl::desc("Mark code section jump table data regions."), 40 cl::Hidden); 41 42void X86MCAsmInfoDarwin::anchor() { } 43 44X86MCAsmInfoDarwin::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. 78 DwarfFDESymbolsUseAbsDiff = T.isMacOSX() && !T.isMacOSXVersionLT(10, 6); 79 80 UseIntegratedAssembler = true; 81} 82 83X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple) 84 : X86MCAsmInfoDarwin(Triple) { 85} 86 87void X86ELFMCAsmInfo::anchor() { } 88 89X86ELFMCAsmInfo::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 // Set up DWARF directives 106 HasLEB128 = true; // Target asm supports leb128 directives (little-endian) 107 108 // Debug Information 109 SupportsDebugInformation = true; 110 111 // Exceptions handling 112 ExceptionsType = ExceptionHandling::DwarfCFI; 113 114 // OpenBSD and Bitrig have buggy support for .quad in 32-bit mode, just split 115 // into two .words. 116 if ((T.getOS() == Triple::OpenBSD || T.getOS() == Triple::Bitrig) && 117 T.getArch() == Triple::x86) 118 Data64bitsDirective = nullptr; 119 120 // Always enable the integrated assembler by default. 121 // Clang also enabled it when the OS is Solaris but that is redundant here. 122 UseIntegratedAssembler = true; 123} 124 125const MCExpr * 126X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym, 127 unsigned Encoding, 128 MCStreamer &Streamer) const { 129 MCContext &Context = Streamer.getContext(); 130 const MCExpr *Res = 131 MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context); 132 const MCExpr *Four = MCConstantExpr::Create(4, Context); 133 return MCBinaryExpr::CreateAdd(Res, Four, Context); 134} 135 136const MCSection *X86ELFMCAsmInfo:: 137getNonexecutableStackSection(MCContext &Ctx) const { 138 return Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS, 139 0, SectionKind::getMetadata()); 140} 141 142void X86MCAsmInfoMicrosoft::anchor() { } 143 144X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) { 145 if (Triple.getArch() == Triple::x86_64) 146 PrivateGlobalPrefix = ".L"; 147 148 AssemblerDialect = AsmWriterFlavor; 149 150 TextAlignFillValue = 0x90; 151 152 AllowAtInName = true; 153 154 UseIntegratedAssembler = true; 155} 156 157void X86MCAsmInfoGNUCOFF::anchor() { } 158 159X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) { 160 if (Triple.getArch() == Triple::x86_64) { 161 PrivateGlobalPrefix = ".L"; 162 PointerSize = 8; 163 } 164 165 AssemblerDialect = AsmWriterFlavor; 166 167 TextAlignFillValue = 0x90; 168 169 // Exceptions handling 170 ExceptionsType = ExceptionHandling::DwarfCFI; 171 172 UseIntegratedAssembler = true; 173} 174