Home | History | Annotate | Download | only in MCTargetDesc 
      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 
     38 static const char *const x86_asm_table[] = {
     39   "{si}", "S",
     40   "{di}", "D",
     41   "{ax}", "a",
     42   "{cx}", "c",
     43   "{memory}", "memory",
     44   "{flags}", "",
     45   "{dirflag}", "",
     46   "{fpsr}", "",
     47   "{fpcr}", "",
     48   "{cc}", "cc",
     49   0,0};
     50 
     51 void X86MCAsmInfoDarwin::anchor() { }
     52 
     53 X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &T) {
     54   bool is64Bit = T.getArch() == Triple::x86_64;
     55   if (is64Bit)
     56     PointerSize = 8;
     57 
     58   AsmTransCBE = x86_asm_table;
     59   AssemblerDialect = AsmWriterFlavor;
     60 
     61   TextAlignFillValue = 0x90;
     62 
     63   if (!is64Bit)
     64     Data64bitsDirective = 0;       // we can't emit a 64-bit unit
     65 
     66   // Use ## as a comment string so that .s files generated by llvm can go
     67   // through the GCC preprocessor without causing an error.  This is needed
     68   // because "clang foo.s" runs the C preprocessor, which is usually reserved
     69   // for .S files on other systems.  Perhaps this is because the file system
     70   // wasn't always case preserving or something.
     71   CommentString = "##";
     72   PCSymbol = ".";
     73 
     74   SupportsDebugInformation = true;
     75   DwarfUsesInlineInfoSection = true;
     76 
     77   // Exceptions handling
     78   ExceptionsType = ExceptionHandling::DwarfCFI;
     79 }
     80 
     81 X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple)
     82   : X86MCAsmInfoDarwin(Triple) {
     83 }
     84 
     85 void X86ELFMCAsmInfo::anchor() { }
     86 
     87 X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
     88   if (T.getArch() == Triple::x86_64)
     89     PointerSize = 8;
     90 
     91   AsmTransCBE = x86_asm_table;
     92   AssemblerDialect = AsmWriterFlavor;
     93 
     94   TextAlignFillValue = 0x90;
     95 
     96   PrivateGlobalPrefix = ".L";
     97   WeakRefDirective = "\t.weak\t";
     98   PCSymbol = ".";
     99 
    100   // Set up DWARF directives
    101   HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
    102 
    103   // Debug Information
    104   SupportsDebugInformation = true;
    105 
    106   // Exceptions handling
    107   ExceptionsType = ExceptionHandling::DwarfCFI;
    108 
    109   // OpenBSD has buggy support for .quad in 32-bit mode, just split into two
    110   // .words.
    111   if (T.getOS() == Triple::OpenBSD && T.getArch() == Triple::x86)
    112     Data64bitsDirective = 0;
    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 const MCSection *X86ELFMCAsmInfo::
    127 getNonexecutableStackSection(MCContext &Ctx) const {
    128   return Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS,
    129                            0, SectionKind::getMetadata());
    130 }
    131 
    132 void X86MCAsmInfoMicrosoft::anchor() { }
    133 
    134 X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) {
    135   if (Triple.getArch() == Triple::x86_64) {
    136     GlobalPrefix = "";
    137     PrivateGlobalPrefix = ".L";
    138   }
    139 
    140   AsmTransCBE = x86_asm_table;
    141   AssemblerDialect = AsmWriterFlavor;
    142 
    143   TextAlignFillValue = 0x90;
    144 }
    145 
    146 void X86MCAsmInfoGNUCOFF::anchor() { }
    147 
    148 X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) {
    149   if (Triple.getArch() == Triple::x86_64) {
    150     GlobalPrefix = "";
    151     PrivateGlobalPrefix = ".L";
    152   }
    153 
    154   AsmTransCBE = x86_asm_table;
    155   AssemblerDialect = AsmWriterFlavor;
    156 
    157   TextAlignFillValue = 0x90;
    158 
    159   // Exceptions handling
    160   ExceptionsType = ExceptionHandling::DwarfCFI;
    161 }
    162