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