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   X86TM = &TM;
  43
  44   // FIXME - Should be simplified.
  45
  46   AsmTransCBE = x86_asm_table;
  47
  48   switch (Subtarget->TargetType) {
  49   case X86Subtarget::isDarwin:
  50     AlignmentIsInBytes = false;
  51     TextAlignFillValue = 0x90;
  52     GlobalPrefix = "_";
  53     if (!Subtarget->is64Bit())
  54       Data64bitsDirective = 0;       // we can't emit a 64-bit unit
  55     ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
  56     PrivateGlobalPrefix = "L";     // Marker for constant pool idxs
  57     BSSSection = 0;                       // no BSS section.
  58     ZeroFillDirective = "\t.zerofill\t";  // Uses .zerofill
  59     ConstantPoolSection = "\t.const\n";
  60     JumpTableDataSection = "\t.const\n";
  61     CStringSection = "\t.cstring";
  62     FourByteConstantSection = "\t.literal4\n";
  63     EightByteConstantSection = "\t.literal8\n";
  64     if (Subtarget->is64Bit())
  65       SixteenByteConstantSection = "\t.literal16\n";
  66     ReadOnlySection = "\t.const\n";
  67     LCOMMDirective = "\t.lcomm\t";
  68     SwitchToSectionDirective = "\t.section ";
  69     COMMDirectiveTakesAlignment = false;
  70     HasDotTypeDotSizeDirective = false;
  71     if (TM.getRelocationModel() == Reloc::Static) {
  72       StaticCtorsSection = ".constructor";
  73       StaticDtorsSection = ".destructor";
  74     } else {
  75       StaticCtorsSection = ".mod_init_func";
  76       StaticDtorsSection = ".mod_term_func";
  77     }
  78     if (Subtarget->is64Bit()) {
  79       PersonalityPrefix = "";
  80       PersonalitySuffix = "+4@GOTPCREL";
  81     } else {
  82       PersonalityPrefix = "L";
  83       PersonalitySuffix = "$non_lazy_ptr";
  84     }
  85     NeedsIndirectEncoding = true;
  86     InlineAsmStart = "# InlineAsm Start";
  87     InlineAsmEnd = "# InlineAsm End";
  88     SetDirective = "\t.set";
  89     PCSymbol = ".";
  90     UsedDirective = "\t.no_dead_strip\t";
  91     WeakDefDirective = "\t.weak_definition ";
  92     WeakRefDirective = "\t.weak_reference ";
  93     HiddenDirective = "\t.private_extern ";
  94     ProtectedDirective = "\t.globl\t";
  95
  96     // In non-PIC modes, emit a special label before jump tables so that the
  97     // linker can perform more accurate dead code stripping.
  98     if (TM.getRelocationModel() != Reloc::PIC_) {
  99       // Emit a local label that is preserved until the linker runs.
 100       JumpTableSpecialLabelPrefix = "l";
 101     }
 102
 103     SupportsDebugInformation = true;
 104     NeedsSet = true;
 105     DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
 106     DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
 107     DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
 108     DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
 109     DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
 110     DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
 111     DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
 112     DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
 113     DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
 114     DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
 115     DwarfMacInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
 116
 117     // Exceptions handling
 118     SupportsExceptionHandling = true;
 119     GlobalEHDirective = "\t.globl\t";
 120     SupportsWeakOmittedEHFrame = false;
 121     AbsoluteEHSectionOffsets = false;
 122     if (Subtarget->is64Bit())
 123       ShortenEHDataOn64Bit = true;
 124     DwarfEHFrameSection =
 125     ".section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support";
 126     DwarfExceptionSection = ".section __DATA,__gcc_except_tab";
 127     break;
 128
 129   case X86Subtarget::isELF:
 130     ReadOnlySection = "\t.section\t.rodata";
 131     FourByteConstantSection = "\t.section\t.rodata.cst4,\"aM\",@progbits,4";
 132     EightByteConstantSection = "\t.section\t.rodata.cst8,\"aM\",@progbits,8";
 133     SixteenByteConstantSection = "\t.section\t.rodata.cst16,\"aM\",@progbits,16";
 134     CStringSection = "\t.section\t.rodata.str1.1,\"aMS\",@progbits,1";
 135     PrivateGlobalPrefix = ".L";
 136     WeakRefDirective = "\t.weak\t";
 137     SetDirective = "\t.set\t";
 138     PCSymbol = ".";
 139
 140     // Set up DWARF directives
 141     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 142
 143     // Debug Information
 144     AbsoluteDebugSectionOffsets = true;
 145     SupportsDebugInformation = true;
 146     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
 147     DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
 148     DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
 149     DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
 150     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
 151     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
 152     DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
 153     DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
 154     DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
 155     DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
 156     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
 157
 158     // Exceptions handling
 159     if (!Subtarget->is64Bit())
 160       SupportsExceptionHandling = true;
 161     AbsoluteEHSectionOffsets = false;
 162     DwarfEHFrameSection = "\t.section\t.eh_frame,\"aw\",@progbits";
 163     DwarfExceptionSection = "\t.section\t.gcc_except_table,\"a\",@progbits";
 164     break;
 165
 166   case X86Subtarget::isCygwin:
 167   case X86Subtarget::isMingw:
 168     GlobalPrefix = "_";
 169     LCOMMDirective = "\t.lcomm\t";
 170     COMMDirectiveTakesAlignment = false;
 171     HasDotTypeDotSizeDirective = false;
 172     StaticCtorsSection = "\t.section .ctors,\"aw\"";
 173     StaticDtorsSection = "\t.section .dtors,\"aw\"";
 174     HiddenDirective = NULL;
 175     PrivateGlobalPrefix = "L";  // Prefix for private global symbols
 176     WeakRefDirective = "\t.weak\t";
 177     SetDirective = "\t.set\t";
 178
 179     // Set up DWARF directives
 180     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 181     AbsoluteDebugSectionOffsets = true;
 182     AbsoluteEHSectionOffsets = false;
 183     SupportsDebugInformation = true;
 184     DwarfSectionOffsetDirective = "\t.secrel32\t";
 185     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
 186     DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
 187     DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
 188     DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
 189     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
 190     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
 191     DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
 192     DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
 193     DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
 194     DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
 195     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
 196     break;
 197
 198   case X86Subtarget::isWindows:
 199     GlobalPrefix = "_";
 200     HasDotTypeDotSizeDirective = false;
 201     break;
 202
 203   default: break;
 204   }
 205
 206   if (Subtarget->isFlavorIntel()) {
 207     GlobalPrefix = "_";
 208     CommentString = ";";
 209
 210     PrivateGlobalPrefix = "$";
 211     AlignDirective = "\talign\t";
 212     ZeroDirective = "\tdb\t";
 213     ZeroDirectiveSuffix = " dup(0)";
 214     AsciiDirective = "\tdb\t";
 215     AscizDirective = 0;
 216     Data8bitsDirective = "\tdb\t";
 217     Data16bitsDirective = "\tdw\t";
 218     Data32bitsDirective = "\tdd\t";
 219     Data64bitsDirective = "\tdq\t";
 220     HasDotTypeDotSizeDirective = false;
 221
 222     TextSection = "_text";
 223     DataSection = "_data";
 224     JumpTableDataSection = NULL;
 225     SwitchToSectionDirective = "";
 226     TextSectionStartSuffix = "\tsegment 'CODE'";
 227     DataSectionStartSuffix = "\tsegment 'DATA'";
 228     SectionEndDirectiveSuffix = "\tends\n";
 229   }
 230
 231   AssemblerDialect = Subtarget->getAsmFlavor();
 232 }
 233
 234 bool X86TargetAsmInfo::LowerToBSwap(CallInst *CI) const {
 235   // FIXME: this should verify that we are targetting a 486 or better.  If not,
 236   // we will turn this bswap into something that will be lowered to logical ops
 237   // instead of emitting the bswap asm.  For now, we don't support 486 or lower
 238   // so don't worry about this.
 239
 240   // Verify this is a simple bswap.
 241   if (CI->getNumOperands() != 2 ||
 242       CI->getType() != CI->getOperand(1)->getType() ||
 243       !CI->getType()->isInteger())
 244     return false;
 245
 246   const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
 247   if (!Ty || Ty->getBitWidth() % 16 != 0)
 248     return false;
 249
 250   // Okay, we can do this xform, do so now.
 251   const Type *Tys[] = { Ty };
 252   Module *M = CI->getParent()->getParent()->getParent();
 253   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
 254
 255   Value *Op = CI->getOperand(1);
 256   Op = new CallInst(Int, Op, CI->getName(), CI);
 257
 258   CI->replaceAllUsesWith(Op);
 259   CI->eraseFromParent();
 260   return true;
 261 }
 262
 263
 264 bool X86TargetAsmInfo::ExpandInlineAsm(CallInst *CI) const {
 265   InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
 266   std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
 267
 268   std::string AsmStr = IA->getAsmString();
 269
 270   // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
 271   std::vector<std::string> AsmPieces;
 272   SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?
 273
 274   switch (AsmPieces.size()) {
 275   default: return false;
 276   case 1:
 277     AsmStr = AsmPieces[0];
 278     AsmPieces.clear();
 279     SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.
 280
 281     // bswap $0
 282     if (AsmPieces.size() == 2 &&
 283         AsmPieces[0] == "bswap" && AsmPieces[1] == "$0") {
 284       // No need to check constraints, nothing other than the equivalent of
 285       // "=r,0" would be valid here.
 286       return LowerToBSwap(CI);
 287     }
 288     break;
 289   case 3:
 290     if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
 291         Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
 292         Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
 293       // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
 294       std::vector<std::string> Words;
 295       SplitString(AsmPieces[0], Words, " \t");
 296       if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
 297         Words.clear();
 298         SplitString(AsmPieces[1], Words, " \t");
 299         if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
 300           Words.clear();
 301           SplitString(AsmPieces[2], Words, " \t,");
 302           if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
 303               Words[2] == "%edx") {
 304             return LowerToBSwap(CI);
 305           }
 306         }
 307       }
 308     }
 309     break;
 310   }
 311   return false;
 312 }
 313
 314 /// PreferredEHDataFormat - This hook allows the target to select data
 315 /// format used for encoding pointers in exception handling data. Reason is
 316 /// 0 for data, 1 for code labels, 2 for function pointers. Global is true
 317 /// if the symbol can be relocated.
 318 unsigned X86TargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
 319                                                  bool Global) const {
 320   const X86Subtarget *Subtarget = &X86TM->getSubtarget<X86Subtarget>();
 321
 322   switch (Subtarget->TargetType) {
 323   case X86Subtarget::isDarwin:
 324    if (Reason == DwarfEncoding::Functions && Global)
 325      return (DW_EH_PE_pcrel | DW_EH_PE_indirect | DW_EH_PE_sdata4);
 326    else if (Reason == DwarfEncoding::CodeLabels || !Global)
 327      return DW_EH_PE_pcrel;
 328    else
 329      return DW_EH_PE_absptr;
 330
 331   case X86Subtarget::isELF:
 332   case X86Subtarget::isCygwin:
 333   case X86Subtarget::isMingw: {
 334     CodeModel::Model CM = X86TM->getCodeModel();
 335
 336     if (X86TM->getRelocationModel() == Reloc::PIC_) {
 337       unsigned Format = 0;
 338
 339       if (!Subtarget->is64Bit())
 340         // 32 bit targets always encode pointers as 4 bytes
 341         Format = DW_EH_PE_sdata4;
 342       else {
 343         // 64 bit targets encode pointers in 4 bytes iff:
 344         // - code model is small OR
 345         // - code model is medium and we're emitting externally visible symbols or
 346         //   any code symbols
 347         if (CM == CodeModel::Small ||
 348             (CM == CodeModel::Medium && (Global ||
 349                                          Reason != DwarfEncoding::Data)))
 350           Format = DW_EH_PE_sdata4;
 351         else
 352           Format = DW_EH_PE_sdata8;
 353       }
 354
 355       if (Global)
 356         Format |= DW_EH_PE_indirect;
 357
 358       return (Format | DW_EH_PE_pcrel);
 359     } else {
 360       if (Subtarget->is64Bit() &&
 361           (CM == CodeModel::Small ||
 362            (CM == CodeModel::Medium && Reason != DwarfEncoding::Data)))
 363         return DW_EH_PE_udata4;
 364       else
 365         return DW_EH_PE_absptr;
 366     }
 367   }
 368
 369   default:
 370    return TargetAsmInfo::PreferredEHDataFormat(Reason, Global);
 371   }
 372 }
 373