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* x86_asm_table[] = {"{si}", "S",
  29                                       "{di}", "D",
  30                                       "{ax}", "a",
  31                                       "{cx}", "c",
  32                                       "{memory}", "memory",
  33                                       "{flags}", "",
  34                                       "{dirflag}", "",
  35                                       "{fpsr}", "",
  36                                       "{cc}", "cc",
  37                                       0,0};
  38
  39 X86TargetAsmInfo::X86TargetAsmInfo(const X86TargetMachine &TM) {
  40   const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
  41   X86TM = &TM;
  42
  43   // FIXME - Should be simplified.
  44
  45   AsmTransCBE = x86_asm_table;
  46
  47   switch (Subtarget->TargetType) {
  48   case X86Subtarget::isDarwin:
  49     AlignmentIsInBytes = false;
  50     GlobalPrefix = "_";
  51     if (!Subtarget->is64Bit())
  52       Data64bitsDirective = 0;       // we can't emit a 64-bit unit
  53     ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
  54     PrivateGlobalPrefix = "L";     // Marker for constant pool idxs
  55     BSSSection = 0;                       // no BSS section.
  56     ZeroFillDirective = "\t.zerofill\t";  // Uses .zerofill
  57     ConstantPoolSection = "\t.const\n";
  58     JumpTableDataSection = "\t.const\n";
  59     CStringSection = "\t.cstring";
  60     FourByteConstantSection = "\t.literal4\n";
  61     EightByteConstantSection = "\t.literal8\n";
  62     if (Subtarget->is64Bit())
  63       SixteenByteConstantSection = "\t.literal16\n";
  64     ReadOnlySection = "\t.const\n";
  65     LCOMMDirective = "\t.lcomm\t";
  66     SwitchToSectionDirective = "\t.section ";
  67     COMMDirectiveTakesAlignment = false;
  68     HasDotTypeDotSizeDirective = false;
  69     if (TM.getRelocationModel() == Reloc::Static) {
  70       StaticCtorsSection = ".constructor";
  71       StaticDtorsSection = ".destructor";
  72     } else {
  73       StaticCtorsSection = ".mod_init_func";
  74       StaticDtorsSection = ".mod_term_func";
  75     }
  76     if (Subtarget->is64Bit()) {
  77       PersonalityPrefix = "";
  78       PersonalitySuffix = "+4@GOTPCREL";
  79     } else {
  80       PersonalityPrefix = "L";
  81       PersonalitySuffix = "$non_lazy_ptr";
  82     }
  83     NeedsIndirectEncoding = true;
  84     InlineAsmStart = "# InlineAsm Start";
  85     InlineAsmEnd = "# InlineAsm End";
  86     SetDirective = "\t.set";
  87     PCSymbol = ".";
  88     UsedDirective = "\t.no_dead_strip\t";
  89     WeakDefDirective = "\t.weak_definition ";
  90     WeakRefDirective = "\t.weak_reference ";
  91     HiddenDirective = "\t.private_extern ";
  92
  93     // In non-PIC modes, emit a special label before jump tables so that the
  94     // linker can perform more accurate dead code stripping.
  95     if (TM.getRelocationModel() != Reloc::PIC_) {
  96       // Emit a local label that is preserved until the linker runs.
  97       JumpTableSpecialLabelPrefix = "l";
  98     }
  99
 100     SupportsDebugInformation = true;
 101     NeedsSet = true;
 102     DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
 103     DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
 104     DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
 105     DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
 106     DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
 107     DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
 108     DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
 109     DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
 110     DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
 111     DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
 112     DwarfMacInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
 113
 114     // Exceptions handling
 115     SupportsExceptionHandling = true;
 116     GlobalEHDirective = "\t.globl\t";
 117     SupportsWeakOmittedEHFrame = false;
 118     AbsoluteEHSectionOffsets = false;
 119     if (Subtarget->is64Bit())
 120       ShortenEHDataOn64Bit = true;
 121     DwarfEHFrameSection =
 122     ".section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support";
 123     DwarfExceptionSection = ".section __DATA,__gcc_except_tab";
 124     break;
 125
 126   case X86Subtarget::isELF:
 127     ReadOnlySection = "\t.section\t.rodata";
 128     FourByteConstantSection = "\t.section\t.rodata.cst4,\"aM\",@progbits,4";
 129     EightByteConstantSection = "\t.section\t.rodata.cst8,\"aM\",@progbits,8";
 130     SixteenByteConstantSection = "\t.section\t.rodata.cst16,\"aM\",@progbits,16";
 131     CStringSection = "\t.section\t.rodata.str1.1,\"aMS\",@progbits,1";
 132     PrivateGlobalPrefix = ".L";
 133     WeakRefDirective = "\t.weak\t";
 134     SetDirective = "\t.set\t";
 135     PCSymbol = ".";
 136
 137     // Set up DWARF directives
 138     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 139
 140     // Debug Information
 141     AbsoluteDebugSectionOffsets = true;
 142     SupportsDebugInformation = true;
 143     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
 144     DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
 145     DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
 146     DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
 147     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
 148     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
 149     DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
 150     DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
 151     DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
 152     DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
 153     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
 154
 155     // Exceptions handling
 156     if (!Subtarget->is64Bit())
 157       SupportsExceptionHandling = true;
 158     AbsoluteEHSectionOffsets = false;
 159     DwarfEHFrameSection = "\t.section\t.eh_frame,\"aw\",@progbits";
 160     DwarfExceptionSection = "\t.section\t.gcc_except_table,\"a\",@progbits";
 161     break;
 162
 163   case X86Subtarget::isCygwin:
 164   case X86Subtarget::isMingw:
 165     GlobalPrefix = "_";
 166     LCOMMDirective = "\t.lcomm\t";
 167     COMMDirectiveTakesAlignment = false;
 168     HasDotTypeDotSizeDirective = false;
 169     StaticCtorsSection = "\t.section .ctors,\"aw\"";
 170     StaticDtorsSection = "\t.section .dtors,\"aw\"";
 171     HiddenDirective = NULL;
 172     PrivateGlobalPrefix = "L";  // Prefix for private global symbols
 173     WeakRefDirective = "\t.weak\t";
 174     SetDirective = "\t.set\t";
 175
 176     // Set up DWARF directives
 177     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 178     AbsoluteDebugSectionOffsets = true;
 179     AbsoluteEHSectionOffsets = false;
 180     SupportsDebugInformation = true;
 181     DwarfSectionOffsetDirective = "\t.secrel32\t";
 182     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
 183     DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
 184     DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
 185     DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
 186     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
 187     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
 188     DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
 189     DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
 190     DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
 191     DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
 192     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
 193     break;
 194
 195   case X86Subtarget::isWindows:
 196     GlobalPrefix = "_";
 197     HasDotTypeDotSizeDirective = false;
 198     break;
 199
 200   default: break;
 201   }
 202
 203   if (Subtarget->isFlavorIntel()) {
 204     GlobalPrefix = "_";
 205     CommentString = ";";
 206
 207     PrivateGlobalPrefix = "$";
 208     AlignDirective = "\talign\t";
 209     ZeroDirective = "\tdb\t";
 210     ZeroDirectiveSuffix = " dup(0)";
 211     AsciiDirective = "\tdb\t";
 212     AscizDirective = 0;
 213     Data8bitsDirective = "\tdb\t";
 214     Data16bitsDirective = "\tdw\t";
 215     Data32bitsDirective = "\tdd\t";
 216     Data64bitsDirective = "\tdq\t";
 217     HasDotTypeDotSizeDirective = false;
 218
 219     TextSection = "_text";
 220     DataSection = "_data";
 221     JumpTableDataSection = NULL;
 222     SwitchToSectionDirective = "";
 223     TextSectionStartSuffix = "\tsegment 'CODE'";
 224     DataSectionStartSuffix = "\tsegment 'DATA'";
 225     SectionEndDirectiveSuffix = "\tends\n";
 226   }
 227
 228   AssemblerDialect = Subtarget->getAsmFlavor();
 229 }
 230
 231 bool X86TargetAsmInfo::LowerToBSwap(CallInst *CI) const {
 232   // FIXME: this should verify that we are targetting a 486 or better.  If not,
 233   // we will turn this bswap into something that will be lowered to logical ops
 234   // instead of emitting the bswap asm.  For now, we don't support 486 or lower
 235   // so don't worry about this.
 236
 237   // Verify this is a simple bswap.
 238   if (CI->getNumOperands() != 2 ||
 239       CI->getType() != CI->getOperand(1)->getType() ||
 240       !CI->getType()->isInteger())
 241     return false;
 242
 243   const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
 244   if (!Ty || Ty->getBitWidth() % 16 != 0)
 245     return false;
 246
 247   // Okay, we can do this xform, do so now.
 248   const Type *Tys[] = { Ty };
 249   Module *M = CI->getParent()->getParent()->getParent();
 250   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
 251
 252   Value *Op = CI->getOperand(1);
 253   Op = new CallInst(Int, Op, CI->getName(), CI);
 254
 255   CI->replaceAllUsesWith(Op);
 256   CI->eraseFromParent();
 257   return true;
 258 }
 259
 260
 261 bool X86TargetAsmInfo::ExpandInlineAsm(CallInst *CI) const {
 262   InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
 263   std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
 264
 265   std::string AsmStr = IA->getAsmString();
 266
 267   // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
 268   std::vector<std::string> AsmPieces;
 269   SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?
 270
 271   switch (AsmPieces.size()) {
 272   default: return false;
 273   case 1:
 274     AsmStr = AsmPieces[0];
 275     AsmPieces.clear();
 276     SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.
 277
 278     // bswap $0
 279     if (AsmPieces.size() == 2 &&
 280         AsmPieces[0] == "bswap" && AsmPieces[1] == "$0") {
 281       // No need to check constraints, nothing other than the equivalent of
 282       // "=r,0" would be valid here.
 283       return LowerToBSwap(CI);
 284     }
 285     break;
 286   case 3:
 287     if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
 288         Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
 289         Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
 290       // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
 291       std::vector<std::string> Words;
 292       SplitString(AsmPieces[0], Words, " \t");
 293       if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
 294         Words.clear();
 295         SplitString(AsmPieces[1], Words, " \t");
 296         if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
 297           Words.clear();
 298           SplitString(AsmPieces[2], Words, " \t,");
 299           if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
 300               Words[2] == "%edx") {
 301             return LowerToBSwap(CI);
 302           }
 303         }
 304       }
 305     }
 306     break;
 307   }
 308   return false;
 309 }
 310
 311 /// PreferredEHDataFormat - This hook allows the target to select data
 312 /// format used for encoding pointers in exception handling data. Reason is
 313 /// 0 for data, 1 for code labels, 2 for function pointers. Global is true
 314 /// if the symbol can be relocated.
 315 unsigned X86TargetAsmInfo::PreferredEHDataFormat(unsigned Reason,
 316                                                  bool Global) const {
 317   const X86Subtarget *Subtarget = &X86TM->getSubtarget<X86Subtarget>();
 318
 319   switch (Subtarget->TargetType) {
 320   case X86Subtarget::isDarwin:
 321    if (Reason == 2 && Global)
 322      return (DW_EH_PE_pcrel | DW_EH_PE_indirect | DW_EH_PE_sdata4);
 323    else if (Reason == 1 || !Global)
 324      return DW_EH_PE_pcrel;
 325    else
 326      return DW_EH_PE_absptr;
 327
 328   case X86Subtarget::isELF:
 329   case X86Subtarget::isCygwin:
 330   case X86Subtarget::isMingw: {
 331     CodeModel::Model CM = X86TM->getCodeModel();
 332
 333     if (X86TM->getRelocationModel() == Reloc::PIC_) {
 334       unsigned Format = 0;
 335
 336       if (!Subtarget->is64Bit())
 337         // 32 bit targets always encode pointers as 4 bytes
 338         Format = DW_EH_PE_sdata4;
 339       else {
 340         // 64 bit targets encode pointers in 4 bytes iff:
 341         // - code model is small OR
 342         // - code model is medium and we're emitting externally visible symbols or
 343         //   any code symbols
 344         if (CM == CodeModel::Small ||
 345             (CM == CodeModel::Medium && (Global || Reason)))
 346           Format = DW_EH_PE_sdata4;
 347         else
 348           Format = DW_EH_PE_sdata8;
 349       }
 350
 351       if (Global)
 352         Format |= DW_EH_PE_indirect;
 353
 354       return (Format | DW_EH_PE_pcrel);
 355     } else {
 356       if (Subtarget->is64Bit() &&
 357           (CM == CodeModel::Small ||
 358            (CM == CodeModel::Medium && Reason)))
 359         return DW_EH_PE_udata4;
 360       else
 361         return DW_EH_PE_absptr;
 362     }
 363   }
 364
 365   default:
 366    return TargetAsmInfo::PreferredEHDataFormat(Reason, Global);
 367   }
 368 }
 369