lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp

   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 }