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   bool is64Bit = DTM->getSubtarget<X86Subtarget>().is64Bit();
 130
 131   AlignmentIsInBytes = false;
 132   TextAlignFillValue = 0x90;
 133   GlobalPrefix = "_";
 134   if (!is64Bit)
 135     Data64bitsDirective = 0;       // we can't emit a 64-bit unit
 136   ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
 137   PrivateGlobalPrefix = "L";     // Marker for constant pool idxs
 138   BSSSection = 0;                       // no BSS section.
 139   ZeroFillDirective = "\t.zerofill\t";  // Uses .zerofill
 140   if (DTM->getRelocationModel() != Reloc::Static)
 141     ConstantPoolSection = "\t.const_data";
 142   else
 143     ConstantPoolSection = "\t.const\n";
 144   JumpTableDataSection = "\t.const\n";
 145   CStringSection = "\t.cstring";
 146   FourByteConstantSection = "\t.literal4\n";
 147   EightByteConstantSection = "\t.literal8\n";
 148   // FIXME: Why don't always use this section?
 149   if (is64Bit) {
 150     SixteenByteConstantSection = "\t.literal16\n";
 151   }
 152   ReadOnlySection = "\t.const\n";
 153
 154   LCOMMDirective = "\t.lcomm\t";
 155   SwitchToSectionDirective = "\t.section ";
 156   StringConstantPrefix = "\1LC";
 157   COMMDirectiveTakesAlignment = false;
 158   HasDotTypeDotSizeDirective = false;
 159   if (TM.getRelocationModel() == Reloc::Static) {
 160     StaticCtorsSection = ".constructor";
 161     StaticDtorsSection = ".destructor";
 162   } else {
 163     StaticCtorsSection = ".mod_init_func";
 164     StaticDtorsSection = ".mod_term_func";
 165   }
 166   if (is64Bit) {
 167     PersonalityPrefix = "";
 168     PersonalitySuffix = "+4@GOTPCREL";
 169   } else {
 170     PersonalityPrefix = "L";
 171     PersonalitySuffix = "$non_lazy_ptr";
 172   }
 173   NeedsIndirectEncoding = true;
 174   InlineAsmStart = "## InlineAsm Start";
 175   InlineAsmEnd = "## InlineAsm End";
 176   CommentString = "##";
 177   SetDirective = "\t.set";
 178   PCSymbol = ".";
 179   UsedDirective = "\t.no_dead_strip\t";
 180   WeakDefDirective = "\t.weak_definition ";
 181   WeakRefDirective = "\t.weak_reference ";
 182   HiddenDirective = "\t.private_extern ";
 183   ProtectedDirective = "\t.globl\t";
 184
 185   // In non-PIC modes, emit a special label before jump tables so that the
 186   // linker can perform more accurate dead code stripping.
 187   if (TM.getRelocationModel() != Reloc::PIC_) {
 188     // Emit a local label that is preserved until the linker runs.
 189     JumpTableSpecialLabelPrefix = "l";
 190   }
 191
 192   SupportsDebugInformation = true;
 193   NeedsSet = true;
 194   DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
 195   DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
 196   DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
 197   DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
 198   DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
 199   DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
 200   DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
 201   DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
 202   DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
 203   DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
 204   DwarfMacInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
 205
 206   // Exceptions handling
 207   SupportsExceptionHandling = true;
 208   GlobalEHDirective = "\t.globl\t";
 209   SupportsWeakOmittedEHFrame = false;
 210   AbsoluteEHSectionOffsets = false;
 211   DwarfEHFrameSection =
 212   ".section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support";
 213   DwarfExceptionSection = ".section __DATA,__gcc_except_tab";
 214 }
 215
 216 unsigned
 217 X86DarwinTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
 218                                               bool Global) const {
 219   if (Reason == DwarfEncoding::Functions && Global)
 220     return (DW_EH_PE_pcrel | DW_EH_PE_indirect | DW_EH_PE_sdata4);
 221   else if (Reason == DwarfEncoding::CodeLabels || !Global)
 222     return DW_EH_PE_pcrel;
 223   else
 224     return DW_EH_PE_absptr;
 225 }
 226
 227 X86ELFTargetAsmInfo::X86ELFTargetAsmInfo(const X86TargetMachine &TM):
 228   X86TargetAsmInfo(TM), ELFTargetAsmInfo(TM) {
 229   bool is64Bit = ETM->getSubtarget<X86Subtarget>().is64Bit();
 230
 231   ReadOnlySection = ".rodata";
 232   FourByteConstantSection = "\t.section\t.rodata.cst4,\"aM\",@progbits,4";
 233   EightByteConstantSection = "\t.section\t.rodata.cst8,\"aM\",@progbits,8";
 234   SixteenByteConstantSection = "\t.section\t.rodata.cst16,\"aM\",@progbits,16";
 235   CStringSection = ".rodata.str";
 236   PrivateGlobalPrefix = ".L";
 237   WeakRefDirective = "\t.weak\t";
 238   SetDirective = "\t.set\t";
 239   PCSymbol = ".";
 240
 241   // Set up DWARF directives
 242   HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 243
 244   // Debug Information
 245   AbsoluteDebugSectionOffsets = true;
 246   SupportsDebugInformation = true;
 247   DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
 248   DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
 249   DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
 250   DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
 251   DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
 252   DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
 253   DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
 254   DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
 255   DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
 256   DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
 257   DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
 258
 259   // Exceptions handling
 260   if (!is64Bit)
 261     SupportsExceptionHandling = true;
 262   AbsoluteEHSectionOffsets = false;
 263   DwarfEHFrameSection = "\t.section\t.eh_frame,\"aw\",@progbits";
 264   DwarfExceptionSection = "\t.section\t.gcc_except_table,\"a\",@progbits";
 265
 266   // On Linux we must declare when we can use a non-executable stack.
 267   if (ETM->getSubtarget<X86Subtarget>().isLinux())
 268     NonexecutableStackDirective = "\t.section\t.note.GNU-stack,\"\",@progbits";
 269 }
 270
 271 unsigned
 272 X86ELFTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
 273                                            bool Global) const {
 274   CodeModel::Model CM = ETM->getCodeModel();
 275   bool is64Bit = ETM->getSubtarget<X86Subtarget>().is64Bit();
 276
 277   if (ETM->getRelocationModel() == Reloc::PIC_) {
 278     unsigned Format = 0;
 279
 280     if (!is64Bit)
 281       // 32 bit targets always encode pointers as 4 bytes
 282       Format = DW_EH_PE_sdata4;
 283     else {
 284       // 64 bit targets encode pointers in 4 bytes iff:
 285       // - code model is small OR
 286       // - code model is medium and we're emitting externally visible symbols
 287       //   or any code symbols
 288       if (CM == CodeModel::Small ||
 289           (CM == CodeModel::Medium && (Global ||
 290                                        Reason != DwarfEncoding::Data)))
 291         Format = DW_EH_PE_sdata4;
 292       else
 293         Format = DW_EH_PE_sdata8;
 294     }
 295
 296     if (Global)
 297       Format |= DW_EH_PE_indirect;
 298
 299     return (Format | DW_EH_PE_pcrel);
 300   } else {
 301     if (is64Bit &&
 302         (CM == CodeModel::Small ||
 303          (CM == CodeModel::Medium && Reason != DwarfEncoding::Data)))
 304       return DW_EH_PE_udata4;
 305     else
 306       return DW_EH_PE_absptr;
 307   }
 308 }
 309
 310 X86COFFTargetAsmInfo::X86COFFTargetAsmInfo(const X86TargetMachine &TM):
 311   X86TargetAsmInfo(TM) {
 312   X86TM = &TM;
 313
 314   GlobalPrefix = "_";
 315   LCOMMDirective = "\t.lcomm\t";
 316   COMMDirectiveTakesAlignment = false;
 317   HasDotTypeDotSizeDirective = false;
 318   StaticCtorsSection = "\t.section .ctors,\"aw\"";
 319   StaticDtorsSection = "\t.section .dtors,\"aw\"";
 320   HiddenDirective = NULL;
 321   PrivateGlobalPrefix = "L";  // Prefix for private global symbols
 322   WeakRefDirective = "\t.weak\t";
 323   SetDirective = "\t.set\t";
 324
 325   // Set up DWARF directives
 326   HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 327   AbsoluteDebugSectionOffsets = true;
 328   AbsoluteEHSectionOffsets = false;
 329   SupportsDebugInformation = true;
 330   DwarfSectionOffsetDirective = "\t.secrel32\t";
 331   DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
 332   DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
 333   DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
 334   DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
 335   DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
 336   DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
 337   DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
 338   DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
 339   DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
 340   DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
 341   DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
 342 }
 343
 344 unsigned
 345 X86COFFTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
 346                                             bool Global) const {
 347   CodeModel::Model CM = X86TM->getCodeModel();
 348   bool is64Bit = X86TM->getSubtarget<X86Subtarget>().is64Bit();
 349
 350   if (X86TM->getRelocationModel() == Reloc::PIC_) {
 351     unsigned Format = 0;
 352
 353     if (!is64Bit)
 354       // 32 bit targets always encode pointers as 4 bytes
 355       Format = DW_EH_PE_sdata4;
 356     else {
 357       // 64 bit targets encode pointers in 4 bytes iff:
 358       // - code model is small OR
 359       // - code model is medium and we're emitting externally visible symbols
 360       //   or any code symbols
 361       if (CM == CodeModel::Small ||
 362           (CM == CodeModel::Medium && (Global ||
 363                                        Reason != DwarfEncoding::Data)))
 364         Format = DW_EH_PE_sdata4;
 365       else
 366         Format = DW_EH_PE_sdata8;
 367     }
 368
 369     if (Global)
 370       Format |= DW_EH_PE_indirect;
 371
 372     return (Format | DW_EH_PE_pcrel);
 373   } else {
 374     if (is64Bit &&
 375         (CM == CodeModel::Small ||
 376          (CM == CodeModel::Medium && Reason != DwarfEncoding::Data)))
 377       return DW_EH_PE_udata4;
 378     else
 379       return DW_EH_PE_absptr;
 380   }
 381 }
 382
 383 std::string
 384 X86COFFTargetAsmInfo::UniqueSectionForGlobal(const GlobalValue* GV,
 385                                              SectionKind::Kind kind) const {
 386   switch (kind) {
 387    case SectionKind::Text:
 388     return ".text$linkonce" + GV->getName();
 389    case SectionKind::Data:
 390    case SectionKind::BSS:
 391    case SectionKind::ThreadData:
 392    case SectionKind::ThreadBSS:
 393     return ".data$linkonce" + GV->getName();
 394    case SectionKind::ROData:
 395    case SectionKind::RODataMergeConst:
 396    case SectionKind::RODataMergeStr:
 397     return ".rdata$linkonce" + GV->getName();
 398    default:
 399     assert(0 && "Unknown section kind");
 400   }
 401 }
 402
 403 std::string X86COFFTargetAsmInfo::PrintSectionFlags(unsigned flags) const {
 404   std::string Flags = ",\"";
 405
 406   if (flags & SectionFlags::Code)
 407     Flags += 'x';
 408   if (flags & SectionFlags::Writeable)
 409     Flags += 'w';
 410
 411   Flags += "\"";
 412
 413   return Flags;
 414 }
 415
 416 X86WinTargetAsmInfo::X86WinTargetAsmInfo(const X86TargetMachine &TM):
 417   X86TargetAsmInfo(TM) {
 418   GlobalPrefix = "_";
 419   CommentString = ";";
 420
 421   PrivateGlobalPrefix = "$";
 422   AlignDirective = "\talign\t";
 423   ZeroDirective = "\tdb\t";
 424   ZeroDirectiveSuffix = " dup(0)";
 425   AsciiDirective = "\tdb\t";
 426   AscizDirective = 0;
 427   Data8bitsDirective = "\tdb\t";
 428   Data16bitsDirective = "\tdw\t";
 429   Data32bitsDirective = "\tdd\t";
 430   Data64bitsDirective = "\tdq\t";
 431   HasDotTypeDotSizeDirective = false;
 432
 433   TextSection = "_text";
 434   DataSection = "_data";
 435   JumpTableDataSection = NULL;
 436   SwitchToSectionDirective = "";
 437   TextSectionStartSuffix = "\tsegment 'CODE'";
 438   DataSectionStartSuffix = "\tsegment 'DATA'";
 439   SectionEndDirectiveSuffix = "\tends\n";
 440 }