lib/Target/X86/X86TargetAsmInfo.cpp

   1 //===-- X86TargetAsmInfo.cpp - X86 asm properties ---------------*- C++ -*-===//
   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 X86TargetAsmInfo properties.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "X86TargetAsmInfo.h"
  15 #include "X86TargetMachine.h"
  16 #include "X86Subtarget.h"
  17 #include "llvm/DerivedTypes.h"
  18 #include "llvm/InlineAsm.h"
  19 #include "llvm/Instructions.h"
  20 #include "llvm/Intrinsics.h"
  21 #include "llvm/Module.h"
  22 #include "llvm/ADT/StringExtras.h"
  23 #include "llvm/Support/Dwarf.h"
  24 #include "llvm/Support/ErrorHandling.h"
  25
  26 using namespace llvm;
  27 using namespace llvm::dwarf;
  28
  29 const char *const llvm::x86_asm_table[] = {
  30   "{si}", "S",
  31   "{di}", "D",
  32   "{ax}", "a",
  33   "{cx}", "c",
  34   "{memory}", "memory",
  35   "{flags}", "",
  36   "{dirflag}", "",
  37   "{fpsr}", "",
  38   "{cc}", "cc",
  39   0,0};
  40
  41 X86DarwinTargetAsmInfo::X86DarwinTargetAsmInfo(const X86TargetMachine &TM):
  42   X86TargetAsmInfo<DarwinTargetAsmInfo>(TM) {
  43   const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
  44   bool is64Bit = Subtarget->is64Bit();
  45
  46   AlignmentIsInBytes = false;
  47   TextAlignFillValue = 0x90;
  48
  49
  50   if (!is64Bit)
  51     Data64bitsDirective = 0;       // we can't emit a 64-bit unit
  52   ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
  53   ZeroFillDirective = "\t.zerofill\t";  // Uses .zerofill
  54   if (TM.getRelocationModel() != Reloc::Static)
  55     ConstantPoolSection = "\t.const_data";
  56   else
  57     ConstantPoolSection = "\t.const\n";
  58   // FIXME: Why don't we always use this section?
  59   if (is64Bit)
  60     SixteenByteConstantSection = getUnnamedSection("\t.literal16\n",
  61                                                    SectionFlags::Mergeable);
  62   LCOMMDirective = "\t.lcomm\t";
  63
  64   // Leopard and above support aligned common symbols.
  65   COMMDirectiveTakesAlignment = (Subtarget->getDarwinVers() >= 9);
  66   HasDotTypeDotSizeDirective = false;
  67   NonLocalEHFrameLabel = true;
  68
  69   if (is64Bit) {
  70     PersonalityPrefix = "";
  71     PersonalitySuffix = "+4@GOTPCREL";
  72   } else {
  73     PersonalityPrefix = "L";
  74     PersonalitySuffix = "$non_lazy_ptr";
  75   }
  76
  77   InlineAsmStart = "## InlineAsm Start";
  78   InlineAsmEnd = "## InlineAsm End";
  79   CommentString = "##";
  80   SetDirective = "\t.set";
  81   PCSymbol = ".";
  82   UsedDirective = "\t.no_dead_strip\t";
  83   ProtectedDirective = "\t.globl\t";
  84
  85   SupportsDebugInformation = true;
  86   DwarfDebugInlineSection = ".section __DWARF,__debug_inlined,regular,debug";
  87   DwarfUsesInlineInfoSection = true;
  88
  89   // Exceptions handling
  90   SupportsExceptionHandling = true;
  91   GlobalEHDirective = "\t.globl\t";
  92   SupportsWeakOmittedEHFrame = false;
  93   AbsoluteEHSectionOffsets = false;
  94   DwarfEHFrameSection =
  95   ".section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support";
  96   DwarfExceptionSection = ".section __DATA,__gcc_except_tab";
  97 }
  98
  99 unsigned
 100 X86DarwinTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
 101                                               bool Global) const {
 102   if (Reason == DwarfEncoding::Functions && Global)
 103     return (DW_EH_PE_pcrel | DW_EH_PE_indirect | DW_EH_PE_sdata4);
 104   else if (Reason == DwarfEncoding::CodeLabels || !Global)
 105     return DW_EH_PE_pcrel;
 106   else
 107     return DW_EH_PE_absptr;
 108 }
 109
 110 const char *
 111 X86DarwinTargetAsmInfo::getEHGlobalPrefix() const
 112 {
 113   const X86Subtarget* Subtarget = &TM.getSubtarget<X86Subtarget>();
 114   if (Subtarget->getDarwinVers() > 9)
 115     return PrivateGlobalPrefix;
 116   else
 117     return "";
 118 }
 119
 120 X86ELFTargetAsmInfo::X86ELFTargetAsmInfo(const X86TargetMachine &TM):
 121   X86TargetAsmInfo<ELFTargetAsmInfo>(TM) {
 122
 123   CStringSection = ".rodata.str";
 124   PrivateGlobalPrefix = ".L";
 125   WeakRefDirective = "\t.weak\t";
 126   SetDirective = "\t.set\t";
 127   PCSymbol = ".";
 128
 129   // Set up DWARF directives
 130   HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 131
 132   // Debug Information
 133   AbsoluteDebugSectionOffsets = true;
 134   SupportsDebugInformation = true;
 135   DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
 136   DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
 137   DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
 138   DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
 139   DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
 140   DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
 141   DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
 142   DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
 143   DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
 144   DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
 145   DwarfMacroInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
 146
 147   // Exceptions handling
 148   SupportsExceptionHandling = true;
 149   AbsoluteEHSectionOffsets = false;
 150   DwarfEHFrameSection = "\t.section\t.eh_frame,\"aw\",@progbits";
 151   DwarfExceptionSection = "\t.section\t.gcc_except_table,\"a\",@progbits";
 152
 153   // On Linux we must declare when we can use a non-executable stack.
 154   if (TM.getSubtarget<X86Subtarget>().isLinux())
 155     NonexecutableStackDirective = "\t.section\t.note.GNU-stack,\"\",@progbits";
 156 }
 157
 158 unsigned
 159 X86ELFTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
 160                                            bool Global) const {
 161   CodeModel::Model CM = TM.getCodeModel();
 162   bool is64Bit = TM.getSubtarget<X86Subtarget>().is64Bit();
 163
 164   if (TM.getRelocationModel() == Reloc::PIC_) {
 165     unsigned Format = 0;
 166
 167     if (!is64Bit)
 168       // 32 bit targets always encode pointers as 4 bytes
 169       Format = DW_EH_PE_sdata4;
 170     else {
 171       // 64 bit targets encode pointers in 4 bytes iff:
 172       // - code model is small OR
 173       // - code model is medium and we're emitting externally visible symbols
 174       //   or any code symbols
 175       if (CM == CodeModel::Small ||
 176           (CM == CodeModel::Medium && (Global ||
 177                                        Reason != DwarfEncoding::Data)))
 178         Format = DW_EH_PE_sdata4;
 179       else
 180         Format = DW_EH_PE_sdata8;
 181     }
 182
 183     if (Global)
 184       Format |= DW_EH_PE_indirect;
 185
 186     return (Format | DW_EH_PE_pcrel);
 187   } else {
 188     if (is64Bit &&
 189         (CM == CodeModel::Small ||
 190          (CM == CodeModel::Medium && Reason != DwarfEncoding::Data)))
 191       return DW_EH_PE_udata4;
 192     else
 193       return DW_EH_PE_absptr;
 194   }
 195 }
 196
 197 X86COFFTargetAsmInfo::X86COFFTargetAsmInfo(const X86TargetMachine &TM):
 198   X86GenericTargetAsmInfo(TM) {
 199
 200   GlobalPrefix = "_";
 201   LCOMMDirective = "\t.lcomm\t";
 202   COMMDirectiveTakesAlignment = false;
 203   HasDotTypeDotSizeDirective = false;
 204   HasSingleParameterDotFile = false;
 205   StaticCtorsSection = "\t.section .ctors,\"aw\"";
 206   StaticDtorsSection = "\t.section .dtors,\"aw\"";
 207   HiddenDirective = NULL;
 208   PrivateGlobalPrefix = "L";  // Prefix for private global symbols
 209   WeakRefDirective = "\t.weak\t";
 210   SetDirective = "\t.set\t";
 211
 212   // Set up DWARF directives
 213   HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 214   AbsoluteDebugSectionOffsets = true;
 215   AbsoluteEHSectionOffsets = false;
 216   SupportsDebugInformation = true;
 217   DwarfSectionOffsetDirective = "\t.secrel32\t";
 218   DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
 219   DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
 220   DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
 221   DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
 222   DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
 223   DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
 224   DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
 225   DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
 226   DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
 227   DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
 228   DwarfMacroInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
 229 }
 230
 231 unsigned
 232 X86COFFTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
 233                                             bool Global) const {
 234   CodeModel::Model CM = TM.getCodeModel();
 235   bool is64Bit = TM.getSubtarget<X86Subtarget>().is64Bit();
 236
 237   if (TM.getRelocationModel() == Reloc::PIC_) {
 238     unsigned Format = 0;
 239
 240     if (!is64Bit)
 241       // 32 bit targets always encode pointers as 4 bytes
 242       Format = DW_EH_PE_sdata4;
 243     else {
 244       // 64 bit targets encode pointers in 4 bytes iff:
 245       // - code model is small OR
 246       // - code model is medium and we're emitting externally visible symbols
 247       //   or any code symbols
 248       if (CM == CodeModel::Small ||
 249           (CM == CodeModel::Medium && (Global ||
 250                                        Reason != DwarfEncoding::Data)))
 251         Format = DW_EH_PE_sdata4;
 252       else
 253         Format = DW_EH_PE_sdata8;
 254     }
 255
 256     if (Global)
 257       Format |= DW_EH_PE_indirect;
 258
 259     return (Format | DW_EH_PE_pcrel);
 260   } else {
 261     if (is64Bit &&
 262         (CM == CodeModel::Small ||
 263          (CM == CodeModel::Medium && Reason != DwarfEncoding::Data)))
 264       return DW_EH_PE_udata4;
 265     else
 266       return DW_EH_PE_absptr;
 267   }
 268 }
 269
 270 std::string
 271 X86COFFTargetAsmInfo::UniqueSectionForGlobal(const GlobalValue* GV,
 272                                              SectionKind::Kind kind) const {
 273   switch (kind) {
 274    case SectionKind::Text:
 275     return ".text$linkonce" + GV->getName();
 276    case SectionKind::Data:
 277    case SectionKind::BSS:
 278    case SectionKind::ThreadData:
 279    case SectionKind::ThreadBSS:
 280     return ".data$linkonce" + GV->getName();
 281    case SectionKind::ROData:
 282    case SectionKind::RODataMergeConst:
 283    case SectionKind::RODataMergeStr:
 284     return ".rdata$linkonce" + GV->getName();
 285    default:
 286     llvm_unreachable("Unknown section kind");
 287   }
 288   return NULL;
 289 }
 290
 291 std::string X86COFFTargetAsmInfo::printSectionFlags(unsigned flags) const {
 292   std::string Flags = ",\"";
 293
 294   if (flags & SectionFlags::Code)
 295     Flags += 'x';
 296   if (flags & SectionFlags::Writeable)
 297     Flags += 'w';
 298
 299   Flags += "\"";
 300
 301   return Flags;
 302 }
 303
 304 X86WinTargetAsmInfo::X86WinTargetAsmInfo(const X86TargetMachine &TM):
 305   X86GenericTargetAsmInfo(TM) {
 306   GlobalPrefix = "_";
 307   CommentString = ";";
 308
 309   InlineAsmStart = "; InlineAsm Start";
 310   InlineAsmEnd   = "; InlineAsm End";
 311
 312   PrivateGlobalPrefix = "$";
 313   AlignDirective = "\tALIGN\t";
 314   ZeroDirective = "\tdb\t";
 315   ZeroDirectiveSuffix = " dup(0)";
 316   AsciiDirective = "\tdb\t";
 317   AscizDirective = 0;
 318   Data8bitsDirective = "\tdb\t";
 319   Data16bitsDirective = "\tdw\t";
 320   Data32bitsDirective = "\tdd\t";
 321   Data64bitsDirective = "\tdq\t";
 322   HasDotTypeDotSizeDirective = false;
 323   HasSingleParameterDotFile = false;
 324
 325   AlignmentIsInBytes = true;
 326
 327   TextSection = getUnnamedSection("_text", SectionFlags::Code);
 328   DataSection = getUnnamedSection("_data", SectionFlags::Writeable);
 329
 330   JumpTableDataSection = NULL;
 331   SwitchToSectionDirective = "";
 332   TextSectionStartSuffix = "\tSEGMENT PARA 'CODE'";
 333   DataSectionStartSuffix = "\tSEGMENT PARA 'DATA'";
 334   SectionEndDirectiveSuffix = "\tends\n";
 335 }
 336
 337 template <class BaseTAI>
 338 bool X86TargetAsmInfo<BaseTAI>::LowerToBSwap(CallInst *CI) const {
 339   // FIXME: this should verify that we are targetting a 486 or better.  If not,
 340   // we will turn this bswap into something that will be lowered to logical ops
 341   // instead of emitting the bswap asm.  For now, we don't support 486 or lower
 342   // so don't worry about this.
 343
 344   // Verify this is a simple bswap.
 345   if (CI->getNumOperands() != 2 ||
 346       CI->getType() != CI->getOperand(1)->getType() ||
 347       !CI->getType()->isInteger())
 348     return false;
 349
 350   const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
 351   if (!Ty || Ty->getBitWidth() % 16 != 0)
 352     return false;
 353
 354   // Okay, we can do this xform, do so now.
 355   const Type *Tys[] = { Ty };
 356   Module *M = CI->getParent()->getParent()->getParent();
 357   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
 358
 359   Value *Op = CI->getOperand(1);
 360   Op = CallInst::Create(Int, Op, CI->getName(), CI);
 361
 362   CI->replaceAllUsesWith(Op);
 363   CI->eraseFromParent();
 364   return true;
 365 }
 366
 367 template <class BaseTAI>
 368 bool X86TargetAsmInfo<BaseTAI>::ExpandInlineAsm(CallInst *CI) const {
 369   InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
 370   std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
 371
 372   std::string AsmStr = IA->getAsmString();
 373
 374   // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
 375   std::vector<std::string> AsmPieces;
 376   SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?
 377
 378   switch (AsmPieces.size()) {
 379   default: return false;
 380   case 1:
 381     AsmStr = AsmPieces[0];
 382     AsmPieces.clear();
 383     SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.
 384
 385     // bswap $0
 386     if (AsmPieces.size() == 2 &&
 387         (AsmPieces[0] == "bswap" ||
 388          AsmPieces[0] == "bswapq" ||
 389          AsmPieces[0] == "bswapl") &&
 390         (AsmPieces[1] == "$0" ||
 391          AsmPieces[1] == "${0:q}")) {
 392       // No need to check constraints, nothing other than the equivalent of
 393       // "=r,0" would be valid here.
 394       return LowerToBSwap(CI);
 395     }
 396     // rorw $$8, ${0:w}  -->  llvm.bswap.i16
 397     if (CI->getType() == Type::Int16Ty &&
 398         AsmPieces.size() == 3 &&
 399         AsmPieces[0] == "rorw" &&
 400         AsmPieces[1] == "$$8," &&
 401         AsmPieces[2] == "${0:w}" &&
 402         IA->getConstraintString() == "=r,0,~{dirflag},~{fpsr},~{flags},~{cc}") {
 403       return LowerToBSwap(CI);
 404     }
 405     break;
 406   case 3:
 407     if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
 408         Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
 409         Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
 410       // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
 411       std::vector<std::string> Words;
 412       SplitString(AsmPieces[0], Words, " \t");
 413       if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
 414         Words.clear();
 415         SplitString(AsmPieces[1], Words, " \t");
 416         if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
 417           Words.clear();
 418           SplitString(AsmPieces[2], Words, " \t,");
 419           if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
 420               Words[2] == "%edx") {
 421             return LowerToBSwap(CI);
 422           }
 423         }
 424       }
 425     }
 426     break;
 427   }
 428   return false;
 429 }
 430
 431 // Instantiate default implementation.
 432 TEMPLATE_INSTANTIATION(class X86TargetAsmInfo<TargetAsmInfo>);