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
  25 using namespace llvm;
  26 using namespace llvm::dwarf;
  27
  28 static const char *const x86_asm_table[] = {
  29                                       "{si}", "S",
  30                                       "{di}", "D",
  31                                       "{ax}", "a",
  32                                       "{cx}", "c",
  33                                       "{memory}", "memory",
  34                                       "{flags}", "",
  35                                       "{dirflag}", "",
  36                                       "{fpsr}", "",
  37                                       "{cc}", "cc",
  38                                       0,0};
  39
  40 X86TargetAsmInfo::X86TargetAsmInfo(const X86TargetMachine &TM) {
  41   const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
  42
  43   AsmTransCBE = x86_asm_table;
  44
  45   AssemblerDialect = Subtarget->getAsmFlavor();
  46 }
  47
  48 bool X86TargetAsmInfo::LowerToBSwap(CallInst *CI) const {
  49   // FIXME: this should verify that we are targetting a 486 or better.  If not,
  50   // we will turn this bswap into something that will be lowered to logical ops
  51   // instead of emitting the bswap asm.  For now, we don't support 486 or lower
  52   // so don't worry about this.
  53
  54   // Verify this is a simple bswap.
  55   if (CI->getNumOperands() != 2 ||
  56       CI->getType() != CI->getOperand(1)->getType() ||
  57       !CI->getType()->isInteger())
  58     return false;
  59
  60   const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
  61   if (!Ty || Ty->getBitWidth() % 16 != 0)
  62     return false;
  63
  64   // Okay, we can do this xform, do so now.
  65   const Type *Tys[] = { Ty };
  66   Module *M = CI->getParent()->getParent()->getParent();
  67   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
  68
  69   Value *Op = CI->getOperand(1);
  70   Op = CallInst::Create(Int, Op, CI->getName(), CI);
  71
  72   CI->replaceAllUsesWith(Op);
  73   CI->eraseFromParent();
  74   return true;
  75 }
  76
  77 bool X86TargetAsmInfo::ExpandInlineAsm(CallInst *CI) const {
  78   InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
  79   std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
  80
  81   std::string AsmStr = IA->getAsmString();
  82
  83   // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
  84   std::vector<std::string> AsmPieces;
  85   SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?
  86
  87   switch (AsmPieces.size()) {
  88   default: return false;
  89   case 1:
  90     AsmStr = AsmPieces[0];
  91     AsmPieces.clear();
  92     SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.
  93
  94     // bswap $0
  95     if (AsmPieces.size() == 2 &&
  96         AsmPieces[0] == "bswap" && AsmPieces[1] == "$0") {
  97       // No need to check constraints, nothing other than the equivalent of
  98       // "=r,0" would be valid here.
  99       return LowerToBSwap(CI);
 100     }
 101     break;
 102   case 3:
 103     if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
 104         Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
 105         Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
 106       // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
 107       std::vector<std::string> Words;
 108       SplitString(AsmPieces[0], Words, " \t");
 109       if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
 110         Words.clear();
 111         SplitString(AsmPieces[1], Words, " \t");
 112         if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
 113           Words.clear();
 114           SplitString(AsmPieces[2], Words, " \t,");
 115           if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
 116               Words[2] == "%edx") {
 117             return LowerToBSwap(CI);
 118           }
 119         }
 120       }
 121     }
 122     break;
 123   }
 124   return false;
 125 }
 126
 127 X86DarwinTargetAsmInfo::X86DarwinTargetAsmInfo(const X86TargetMachine &TM):
 128   X86TargetAsmInfo(TM), DarwinTargetAsmInfo(TM) {
 129   const X86Subtarget* Subtarget = &DTM->getSubtarget<X86Subtarget>();
 130   bool is64Bit = Subtarget->is64Bit();
 131
 132   AlignmentIsInBytes = false;
 133   TextAlignFillValue = 0x90;
 134   GlobalPrefix = "_";
 135   if (!is64Bit)
 136     Data64bitsDirective = 0;       // we can't emit a 64-bit unit
 137   ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
 138   PrivateGlobalPrefix = "L";     // Marker for constant pool idxs
 139   LessPrivateGlobalPrefix = "l";  // Marker for some ObjC metadata
 140   BSSSection = 0;                       // no BSS section.
 141   ZeroFillDirective = "\t.zerofill\t";  // Uses .zerofill
 142   if (DTM->getRelocationModel() != Reloc::Static)
 143     ConstantPoolSection = "\t.const_data";
 144   else
 145     ConstantPoolSection = "\t.const\n";
 146   JumpTableDataSection = "\t.const\n";
 147   CStringSection = "\t.cstring";
 148   FourByteConstantSection = "\t.literal4\n";
 149   EightByteConstantSection = "\t.literal8\n";
 150   // FIXME: Why don't always use this section?
 151   if (is64Bit) {
 152     SixteenByteConstantSection = "\t.literal16\n";
 153     SixteenByteConstantSection_ = getUnnamedSection("\t.literal16\n",
 154                                                     SectionFlags::Mergeable);
 155   }
 156   ReadOnlySection = "\t.const\n";
 157
 158   LCOMMDirective = "\t.lcomm\t";
 159   SwitchToSectionDirective = "\t.section ";
 160   StringConstantPrefix = "\1LC";
 161   // Leopard and above support aligned common symbols.
 162   COMMDirectiveTakesAlignment = (Subtarget->getDarwinVers() >= 9);
 163   HasDotTypeDotSizeDirective = false;
 164   if (TM.getRelocationModel() == Reloc::Static) {
 165     StaticCtorsSection = ".constructor";
 166     StaticDtorsSection = ".destructor";
 167   } else {
 168     StaticCtorsSection = ".mod_init_func";
 169     StaticDtorsSection = ".mod_term_func";
 170   }
 171   if (is64Bit) {
 172     PersonalityPrefix = "";
 173     PersonalitySuffix = "+4@GOTPCREL";
 174   } else {
 175     PersonalityPrefix = "L";
 176     PersonalitySuffix = "$non_lazy_ptr";
 177   }
 178   NeedsIndirectEncoding = true;
 179   InlineAsmStart = "## InlineAsm Start";
 180   InlineAsmEnd = "## InlineAsm End";
 181   CommentString = "##";
 182   SetDirective = "\t.set";
 183   PCSymbol = ".";
 184   UsedDirective = "\t.no_dead_strip\t";
 185   WeakDefDirective = "\t.weak_definition ";
 186   WeakRefDirective = "\t.weak_reference ";
 187   HiddenDirective = "\t.private_extern ";
 188   ProtectedDirective = "\t.globl\t";
 189
 190   // In non-PIC modes, emit a special label before jump tables so that the
 191   // linker can perform more accurate dead code stripping.
 192   if (TM.getRelocationModel() != Reloc::PIC_) {
 193     // Emit a local label that is preserved until the linker runs.
 194     JumpTableSpecialLabelPrefix = "l";
 195   }
 196
 197   SupportsDebugInformation = true;
 198   NeedsSet = true;
 199   DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
 200   DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
 201   DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
 202   DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
 203   DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
 204   DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
 205   DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
 206   DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
 207   DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
 208   DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
 209   DwarfMacInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
 210
 211   // Exceptions handling
 212   SupportsExceptionHandling = true;
 213   GlobalEHDirective = "\t.globl\t";
 214   SupportsWeakOmittedEHFrame = false;
 215   AbsoluteEHSectionOffsets = false;
 216   DwarfEHFrameSection =
 217   ".section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support";
 218   DwarfExceptionSection = ".section __DATA,__gcc_except_tab";
 219 }
 220
 221 unsigned
 222 X86DarwinTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
 223                                               bool Global) const {
 224   if (Reason == DwarfEncoding::Functions && Global)
 225     return (DW_EH_PE_pcrel | DW_EH_PE_indirect | DW_EH_PE_sdata4);
 226   else if (Reason == DwarfEncoding::CodeLabels || !Global)
 227     return DW_EH_PE_pcrel;
 228   else
 229     return DW_EH_PE_absptr;
 230 }
 231
 232 X86ELFTargetAsmInfo::X86ELFTargetAsmInfo(const X86TargetMachine &TM):
 233   X86TargetAsmInfo(TM), ELFTargetAsmInfo(TM) {
 234
 235   ReadOnlySection = ".rodata";
 236   FourByteConstantSection = "\t.section\t.rodata.cst4,\"aM\",@progbits,4";
 237   EightByteConstantSection = "\t.section\t.rodata.cst8,\"aM\",@progbits,8";
 238   SixteenByteConstantSection = "\t.section\t.rodata.cst16,\"aM\",@progbits,16";
 239   CStringSection = ".rodata.str";
 240   PrivateGlobalPrefix = ".L";
 241   WeakRefDirective = "\t.weak\t";
 242   SetDirective = "\t.set\t";
 243   PCSymbol = ".";
 244
 245   // Set up DWARF directives
 246   HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 247
 248   // Debug Information
 249   AbsoluteDebugSectionOffsets = true;
 250   SupportsDebugInformation = true;
 251   DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
 252   DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
 253   DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
 254   DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
 255   DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
 256   DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
 257   DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
 258   DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
 259   DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
 260   DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
 261   DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
 262
 263   // Exceptions handling
 264   SupportsExceptionHandling = true;
 265   AbsoluteEHSectionOffsets = false;
 266   DwarfEHFrameSection = "\t.section\t.eh_frame,\"aw\",@progbits";
 267   DwarfExceptionSection = "\t.section\t.gcc_except_table,\"a\",@progbits";
 268
 269   // On Linux we must declare when we can use a non-executable stack.
 270   if (ETM->getSubtarget<X86Subtarget>().isLinux())
 271     NonexecutableStackDirective = "\t.section\t.note.GNU-stack,\"\",@progbits";
 272 }
 273
 274 unsigned
 275 X86ELFTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
 276                                            bool Global) const {
 277   CodeModel::Model CM = ETM->getCodeModel();
 278   bool is64Bit = ETM->getSubtarget<X86Subtarget>().is64Bit();
 279
 280   if (ETM->getRelocationModel() == Reloc::PIC_) {
 281     unsigned Format = 0;
 282
 283     if (!is64Bit)
 284       // 32 bit targets always encode pointers as 4 bytes
 285       Format = DW_EH_PE_sdata4;
 286     else {
 287       // 64 bit targets encode pointers in 4 bytes iff:
 288       // - code model is small OR
 289       // - code model is medium and we're emitting externally visible symbols
 290       //   or any code symbols
 291       if (CM == CodeModel::Small ||
 292           (CM == CodeModel::Medium && (Global ||
 293                                        Reason != DwarfEncoding::Data)))
 294         Format = DW_EH_PE_sdata4;
 295       else
 296         Format = DW_EH_PE_sdata8;
 297     }
 298
 299     if (Global)
 300       Format |= DW_EH_PE_indirect;
 301
 302     return (Format | DW_EH_PE_pcrel);
 303   } else {
 304     if (is64Bit &&
 305         (CM == CodeModel::Small ||
 306          (CM == CodeModel::Medium && Reason != DwarfEncoding::Data)))
 307       return DW_EH_PE_udata4;
 308     else
 309       return DW_EH_PE_absptr;
 310   }
 311 }
 312
 313 X86COFFTargetAsmInfo::X86COFFTargetAsmInfo(const X86TargetMachine &TM):
 314   X86TargetAsmInfo(TM) {
 315   X86TM = &TM;
 316
 317   GlobalPrefix = "_";
 318   LCOMMDirective = "\t.lcomm\t";
 319   COMMDirectiveTakesAlignment = false;
 320   HasDotTypeDotSizeDirective = false;
 321   StaticCtorsSection = "\t.section .ctors,\"aw\"";
 322   StaticDtorsSection = "\t.section .dtors,\"aw\"";
 323   HiddenDirective = NULL;
 324   PrivateGlobalPrefix = "L";  // Prefix for private global symbols
 325   WeakRefDirective = "\t.weak\t";
 326   SetDirective = "\t.set\t";
 327
 328   // Set up DWARF directives
 329   HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 330   AbsoluteDebugSectionOffsets = true;
 331   AbsoluteEHSectionOffsets = false;
 332   SupportsDebugInformation = true;
 333   DwarfSectionOffsetDirective = "\t.secrel32\t";
 334   DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
 335   DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
 336   DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
 337   DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
 338   DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
 339   DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
 340   DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
 341   DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
 342   DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
 343   DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
 344   DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
 345 }
 346
 347 unsigned
 348 X86COFFTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
 349                                             bool Global) const {
 350   CodeModel::Model CM = X86TM->getCodeModel();
 351   bool is64Bit = X86TM->getSubtarget<X86Subtarget>().is64Bit();
 352
 353   if (X86TM->getRelocationModel() == Reloc::PIC_) {
 354     unsigned Format = 0;
 355
 356     if (!is64Bit)
 357       // 32 bit targets always encode pointers as 4 bytes
 358       Format = DW_EH_PE_sdata4;
 359     else {
 360       // 64 bit targets encode pointers in 4 bytes iff:
 361       // - code model is small OR
 362       // - code model is medium and we're emitting externally visible symbols
 363       //   or any code symbols
 364       if (CM == CodeModel::Small ||
 365           (CM == CodeModel::Medium && (Global ||
 366                                        Reason != DwarfEncoding::Data)))
 367         Format = DW_EH_PE_sdata4;
 368       else
 369         Format = DW_EH_PE_sdata8;
 370     }
 371
 372     if (Global)
 373       Format |= DW_EH_PE_indirect;
 374
 375     return (Format | DW_EH_PE_pcrel);
 376   } else {
 377     if (is64Bit &&
 378         (CM == CodeModel::Small ||
 379          (CM == CodeModel::Medium && Reason != DwarfEncoding::Data)))
 380       return DW_EH_PE_udata4;
 381     else
 382       return DW_EH_PE_absptr;
 383   }
 384 }
 385
 386 std::string
 387 X86COFFTargetAsmInfo::UniqueSectionForGlobal(const GlobalValue* GV,
 388                                              SectionKind::Kind kind) const {
 389   switch (kind) {
 390    case SectionKind::Text:
 391     return ".text$linkonce" + GV->getName();
 392    case SectionKind::Data:
 393    case SectionKind::BSS:
 394    case SectionKind::ThreadData:
 395    case SectionKind::ThreadBSS:
 396     return ".data$linkonce" + GV->getName();
 397    case SectionKind::ROData:
 398    case SectionKind::RODataMergeConst:
 399    case SectionKind::RODataMergeStr:
 400     return ".rdata$linkonce" + GV->getName();
 401    default:
 402     assert(0 && "Unknown section kind");
 403   }
 404 }
 405
 406 std::string X86COFFTargetAsmInfo::printSectionFlags(unsigned flags) const {
 407   std::string Flags = ",\"";
 408
 409   if (flags & SectionFlags::Code)
 410     Flags += 'x';
 411   if (flags & SectionFlags::Writeable)
 412     Flags += 'w';
 413
 414   Flags += "\"";
 415
 416   return Flags;
 417 }
 418
 419 X86WinTargetAsmInfo::X86WinTargetAsmInfo(const X86TargetMachine &TM):
 420   X86TargetAsmInfo(TM) {
 421   GlobalPrefix = "_";
 422   CommentString = ";";
 423
 424   PrivateGlobalPrefix = "$";
 425   AlignDirective = "\talign\t";
 426   ZeroDirective = "\tdb\t";
 427   ZeroDirectiveSuffix = " dup(0)";
 428   AsciiDirective = "\tdb\t";
 429   AscizDirective = 0;
 430   Data8bitsDirective = "\tdb\t";
 431   Data16bitsDirective = "\tdw\t";
 432   Data32bitsDirective = "\tdd\t";
 433   Data64bitsDirective = "\tdq\t";
 434   HasDotTypeDotSizeDirective = false;
 435
 436   TextSection = getUnnamedSection("_text", SectionFlags::Code);
 437   DataSection = "_data";
 438   JumpTableDataSection = NULL;
 439   SwitchToSectionDirective = "";
 440   TextSectionStartSuffix = "\tsegment 'CODE'";
 441   DataSectionStartSuffix = "\tsegment 'DATA'";
 442   SectionEndDirectiveSuffix = "\tends\n";
 443 }