tools/llvm-mc/AsmParser.cpp

   1 //===- AsmParser.cpp - Parser for Assembly Files --------------------------===//
   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 class implements the parser for assembly files.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "AsmParser.h"
  15
  16 #include "llvm/ADT/SmallString.h"
  17 #include "llvm/ADT/Twine.h"
  18 #include "llvm/MC/MCContext.h"
  19 #include "llvm/MC/MCExpr.h"
  20 #include "llvm/MC/MCInst.h"
  21 #include "llvm/MC/MCSectionMachO.h"
  22 #include "llvm/MC/MCStreamer.h"
  23 #include "llvm/MC/MCSymbol.h"
  24 #include "llvm/Support/SourceMgr.h"
  25 #include "llvm/Support/raw_ostream.h"
  26 #include "llvm/Target/TargetAsmParser.h"
  27 using namespace llvm;
  28
  29 // Mach-O section uniquing.
  30 //
  31 // FIXME: Figure out where this should live, it should be shared by
  32 // TargetLoweringObjectFile.
  33 typedef StringMap<const MCSectionMachO*> MachOUniqueMapTy;
  34
  35 AsmParser::~AsmParser() {
  36   // If we have the MachO uniquing map, free it.
  37   delete (MachOUniqueMapTy*)SectionUniquingMap;
  38 }
  39
  40 const MCSection *AsmParser::getMachOSection(const StringRef &Segment,
  41                                             const StringRef &Section,
  42                                             unsigned TypeAndAttributes,
  43                                             unsigned Reserved2,
  44                                             SectionKind Kind) const {
  45   // We unique sections by their segment/section pair.  The returned section
  46   // may not have the same flags as the requested section, if so this should be
  47   // diagnosed by the client as an error.
  48
  49   // Create the map if it doesn't already exist.
  50   if (SectionUniquingMap == 0)
  51     SectionUniquingMap = new MachOUniqueMapTy();
  52   MachOUniqueMapTy &Map = *(MachOUniqueMapTy*)SectionUniquingMap;
  53
  54   // Form the name to look up.
  55   SmallString<64> Name;
  56   Name += Segment;
  57   Name.push_back(',');
  58   Name += Section;
  59
  60   // Do the lookup, if we have a hit, return it.
  61   const MCSectionMachO *&Entry = Map[Name.str()];
  62
  63   // FIXME: This should validate the type and attributes.
  64   if (Entry) return Entry;
  65
  66   // Otherwise, return a new section.
  67   return Entry = MCSectionMachO::Create(Segment, Section, TypeAndAttributes,
  68                                         Reserved2, Kind, Ctx);
  69 }
  70
  71 void AsmParser::Warning(SMLoc L, const Twine &Msg) {
  72   Lexer.PrintMessage(L, Msg.str(), "warning");
  73 }
  74
  75 bool AsmParser::Error(SMLoc L, const Twine &Msg) {
  76   Lexer.PrintMessage(L, Msg.str(), "error");
  77   return true;
  78 }
  79
  80 bool AsmParser::TokError(const char *Msg) {
  81   Lexer.PrintMessage(Lexer.getLoc(), Msg, "error");
  82   return true;
  83 }
  84
  85 bool AsmParser::Run() {
  86   // Create the initial section.
  87   //
  88   // FIXME: Support -n.
  89   // FIXME: Target hook & command line option for initial section.
  90   Out.SwitchSection(getMachOSection("__TEXT", "__text",
  91                                     MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
  92                                     0, SectionKind()));
  93
  94
  95   // Prime the lexer.
  96   Lexer.Lex();
  97
  98   bool HadError = false;
  99
 100   AsmCond StartingCondState = TheCondState;
 101
 102   // While we have input, parse each statement.
 103   while (Lexer.isNot(AsmToken::Eof)) {
 104     // Handle conditional assembly here before calling ParseStatement()
 105     if (Lexer.getKind() == AsmToken::Identifier) {
 106       // If we have an identifier, handle it as the key symbol.
 107       AsmToken ID = Lexer.getTok();
 108       SMLoc IDLoc = ID.getLoc();
 109       StringRef IDVal = ID.getString();
 110
 111       if (IDVal == ".if" ||
 112           IDVal == ".elseif" ||
 113           IDVal == ".else" ||
 114           IDVal == ".endif") {
 115         if (!ParseConditionalAssemblyDirectives(IDVal, IDLoc))
 116           continue;
 117         HadError = true;
 118         EatToEndOfStatement();
 119         continue;
 120       }
 121     }
 122     if (TheCondState.Ignore) {
 123       EatToEndOfStatement();
 124       continue;
 125     }
 126
 127     if (!ParseStatement()) continue;
 128
 129     // We had an error, remember it and recover by skipping to the next line.
 130     HadError = true;
 131     EatToEndOfStatement();
 132   }
 133
 134   if (TheCondState.TheCond != StartingCondState.TheCond ||
 135       TheCondState.Ignore != StartingCondState.Ignore)
 136     return TokError("unmatched .ifs or .elses");
 137
 138   if (!HadError)
 139     Out.Finish();
 140
 141   return HadError;
 142 }
 143
 144 /// ParseConditionalAssemblyDirectives - parse the conditional assembly
 145 /// directives
 146 bool AsmParser::ParseConditionalAssemblyDirectives(StringRef Directive,
 147                                                    SMLoc DirectiveLoc) {
 148   if (Directive == ".if")
 149     return ParseDirectiveIf(DirectiveLoc);
 150   if (Directive == ".elseif")
 151     return ParseDirectiveElseIf(DirectiveLoc);
 152   if (Directive == ".else")
 153     return ParseDirectiveElse(DirectiveLoc);
 154   if (Directive == ".endif")
 155     return ParseDirectiveEndIf(DirectiveLoc);
 156   return true;
 157 }
 158
 159 /// EatToEndOfStatement - Throw away the rest of the line for testing purposes.
 160 void AsmParser::EatToEndOfStatement() {
 161   while (Lexer.isNot(AsmToken::EndOfStatement) &&
 162          Lexer.isNot(AsmToken::Eof))
 163     Lexer.Lex();
 164
 165   // Eat EOL.
 166   if (Lexer.is(AsmToken::EndOfStatement))
 167     Lexer.Lex();
 168 }
 169
 170
 171 /// ParseParenExpr - Parse a paren expression and return it.
 172 /// NOTE: This assumes the leading '(' has already been consumed.
 173 ///
 174 /// parenexpr ::= expr)
 175 ///
 176 bool AsmParser::ParseParenExpr(const MCExpr *&Res) {
 177   if (ParseExpression(Res)) return true;
 178   if (Lexer.isNot(AsmToken::RParen))
 179     return TokError("expected ')' in parentheses expression");
 180   Lexer.Lex();
 181   return false;
 182 }
 183
 184 MCSymbol *AsmParser::CreateSymbol(StringRef Name) {
 185   if (MCSymbol *S = Ctx.LookupSymbol(Name))
 186     return S;
 187
 188   // If the label starts with L it is an assembler temporary label.
 189   if (Name.startswith("L"))
 190     return Ctx.CreateTemporarySymbol(Name);
 191
 192   return Ctx.CreateSymbol(Name);
 193 }
 194
 195 /// ParsePrimaryExpr - Parse a primary expression and return it.
 196 ///  primaryexpr ::= (parenexpr
 197 ///  primaryexpr ::= symbol
 198 ///  primaryexpr ::= number
 199 ///  primaryexpr ::= ~,+,- primaryexpr
 200 bool AsmParser::ParsePrimaryExpr(const MCExpr *&Res) {
 201   switch (Lexer.getKind()) {
 202   default:
 203     return TokError("unknown token in expression");
 204   case AsmToken::Exclaim:
 205     Lexer.Lex(); // Eat the operator.
 206     if (ParsePrimaryExpr(Res))
 207       return true;
 208     Res = MCUnaryExpr::CreateLNot(Res, getContext());
 209     return false;
 210   case AsmToken::String:
 211   case AsmToken::Identifier: {
 212     // This is a label, this should be parsed as part of an expression, to
 213     // handle things like LFOO+4.
 214     MCSymbol *Sym = CreateSymbol(Lexer.getTok().getIdentifier());
 215
 216     Res = MCSymbolRefExpr::Create(Sym, getContext());
 217     Lexer.Lex(); // Eat identifier.
 218     return false;
 219   }
 220   case AsmToken::Integer:
 221     Res = MCConstantExpr::Create(Lexer.getTok().getIntVal(), getContext());
 222     Lexer.Lex(); // Eat token.
 223     return false;
 224   case AsmToken::LParen:
 225     Lexer.Lex(); // Eat the '('.
 226     return ParseParenExpr(Res);
 227   case AsmToken::Minus:
 228     Lexer.Lex(); // Eat the operator.
 229     if (ParsePrimaryExpr(Res))
 230       return true;
 231     Res = MCUnaryExpr::CreateMinus(Res, getContext());
 232     return false;
 233   case AsmToken::Plus:
 234     Lexer.Lex(); // Eat the operator.
 235     if (ParsePrimaryExpr(Res))
 236       return true;
 237     Res = MCUnaryExpr::CreatePlus(Res, getContext());
 238     return false;
 239   case AsmToken::Tilde:
 240     Lexer.Lex(); // Eat the operator.
 241     if (ParsePrimaryExpr(Res))
 242       return true;
 243     Res = MCUnaryExpr::CreateNot(Res, getContext());
 244     return false;
 245   }
 246 }
 247
 248 /// ParseExpression - Parse an expression and return it.
 249 ///
 250 ///  expr ::= expr +,- expr          -> lowest.
 251 ///  expr ::= expr |,^,&,! expr      -> middle.
 252 ///  expr ::= expr *,/,%,<<,>> expr  -> highest.
 253 ///  expr ::= primaryexpr
 254 ///
 255 bool AsmParser::ParseExpression(const MCExpr *&Res) {
 256   Res = 0;
 257   return ParsePrimaryExpr(Res) ||
 258          ParseBinOpRHS(1, Res);
 259 }
 260
 261 bool AsmParser::ParseParenExpression(const MCExpr *&Res) {
 262   if (ParseParenExpr(Res))
 263     return true;
 264
 265   return false;
 266 }
 267
 268 bool AsmParser::ParseAbsoluteExpression(int64_t &Res) {
 269   const MCExpr *Expr;
 270
 271   SMLoc StartLoc = Lexer.getLoc();
 272   if (ParseExpression(Expr))
 273     return true;
 274
 275   if (!Expr->EvaluateAsAbsolute(Ctx, Res))
 276     return Error(StartLoc, "expected absolute expression");
 277
 278   return false;
 279 }
 280
 281 static unsigned getBinOpPrecedence(AsmToken::TokenKind K,
 282                                    MCBinaryExpr::Opcode &Kind) {
 283   switch (K) {
 284   default:
 285     return 0;    // not a binop.
 286
 287     // Lowest Precedence: &&, ||
 288   case AsmToken::AmpAmp:
 289     Kind = MCBinaryExpr::LAnd;
 290     return 1;
 291   case AsmToken::PipePipe:
 292     Kind = MCBinaryExpr::LOr;
 293     return 1;
 294
 295     // Low Precedence: +, -, ==, !=, <>, <, <=, >, >=
 296   case AsmToken::Plus:
 297     Kind = MCBinaryExpr::Add;
 298     return 2;
 299   case AsmToken::Minus:
 300     Kind = MCBinaryExpr::Sub;
 301     return 2;
 302   case AsmToken::EqualEqual:
 303     Kind = MCBinaryExpr::EQ;
 304     return 2;
 305   case AsmToken::ExclaimEqual:
 306   case AsmToken::LessGreater:
 307     Kind = MCBinaryExpr::NE;
 308     return 2;
 309   case AsmToken::Less:
 310     Kind = MCBinaryExpr::LT;
 311     return 2;
 312   case AsmToken::LessEqual:
 313     Kind = MCBinaryExpr::LTE;
 314     return 2;
 315   case AsmToken::Greater:
 316     Kind = MCBinaryExpr::GT;
 317     return 2;
 318   case AsmToken::GreaterEqual:
 319     Kind = MCBinaryExpr::GTE;
 320     return 2;
 321
 322     // Intermediate Precedence: |, &, ^
 323     //
 324     // FIXME: gas seems to support '!' as an infix operator?
 325   case AsmToken::Pipe:
 326     Kind = MCBinaryExpr::Or;
 327     return 3;
 328   case AsmToken::Caret:
 329     Kind = MCBinaryExpr::Xor;
 330     return 3;
 331   case AsmToken::Amp:
 332     Kind = MCBinaryExpr::And;
 333     return 3;
 334
 335     // Highest Precedence: *, /, %, <<, >>
 336   case AsmToken::Star:
 337     Kind = MCBinaryExpr::Mul;
 338     return 4;
 339   case AsmToken::Slash:
 340     Kind = MCBinaryExpr::Div;
 341     return 4;
 342   case AsmToken::Percent:
 343     Kind = MCBinaryExpr::Mod;
 344     return 4;
 345   case AsmToken::LessLess:
 346     Kind = MCBinaryExpr::Shl;
 347     return 4;
 348   case AsmToken::GreaterGreater:
 349     Kind = MCBinaryExpr::Shr;
 350     return 4;
 351   }
 352 }
 353
 354
 355 /// ParseBinOpRHS - Parse all binary operators with precedence >= 'Precedence'.
 356 /// Res contains the LHS of the expression on input.
 357 bool AsmParser::ParseBinOpRHS(unsigned Precedence, const MCExpr *&Res) {
 358   while (1) {
 359     MCBinaryExpr::Opcode Kind = MCBinaryExpr::Add;
 360     unsigned TokPrec = getBinOpPrecedence(Lexer.getKind(), Kind);
 361
 362     // If the next token is lower precedence than we are allowed to eat, return
 363     // successfully with what we ate already.
 364     if (TokPrec < Precedence)
 365       return false;
 366
 367     Lexer.Lex();
 368
 369     // Eat the next primary expression.
 370     const MCExpr *RHS;
 371     if (ParsePrimaryExpr(RHS)) return true;
 372
 373     // If BinOp binds less tightly with RHS than the operator after RHS, let
 374     // the pending operator take RHS as its LHS.
 375     MCBinaryExpr::Opcode Dummy;
 376     unsigned NextTokPrec = getBinOpPrecedence(Lexer.getKind(), Dummy);
 377     if (TokPrec < NextTokPrec) {
 378       if (ParseBinOpRHS(Precedence+1, RHS)) return true;
 379     }
 380
 381     // Merge LHS and RHS according to operator.
 382     Res = MCBinaryExpr::Create(Kind, Res, RHS, getContext());
 383   }
 384 }
 385
 386
 387
 388
 389 /// ParseStatement:
 390 ///   ::= EndOfStatement
 391 ///   ::= Label* Directive ...Operands... EndOfStatement
 392 ///   ::= Label* Identifier OperandList* EndOfStatement
 393 bool AsmParser::ParseStatement() {
 394   if (Lexer.is(AsmToken::EndOfStatement)) {
 395     Lexer.Lex();
 396     return false;
 397   }
 398
 399   // Statements always start with an identifier.
 400   AsmToken ID = Lexer.getTok();
 401   SMLoc IDLoc = ID.getLoc();
 402   StringRef IDVal;
 403   if (ParseIdentifier(IDVal))
 404     return TokError("unexpected token at start of statement");
 405
 406   // FIXME: Recurse on local labels?
 407
 408   // See what kind of statement we have.
 409   switch (Lexer.getKind()) {
 410   case AsmToken::Colon: {
 411     // identifier ':'   -> Label.
 412     Lexer.Lex();
 413
 414     // Diagnose attempt to use a variable as a label.
 415     //
 416     // FIXME: Diagnostics. Note the location of the definition as a label.
 417     // FIXME: This doesn't diagnose assignment to a symbol which has been
 418     // implicitly marked as external.
 419     MCSymbol *Sym = CreateSymbol(IDVal);
 420     if (!Sym->isUndefined())
 421       return Error(IDLoc, "invalid symbol redefinition");
 422
 423     // Emit the label.
 424     Out.EmitLabel(Sym);
 425
 426     return ParseStatement();
 427   }
 428
 429   case AsmToken::Equal:
 430     // identifier '=' ... -> assignment statement
 431     Lexer.Lex();
 432
 433     return ParseAssignment(IDVal);
 434
 435   default: // Normal instruction or directive.
 436     break;
 437   }
 438
 439   // Otherwise, we have a normal instruction or directive.
 440   if (IDVal[0] == '.') {
 441     // FIXME: This should be driven based on a hash lookup and callback.
 442     if (IDVal == ".section")
 443       return ParseDirectiveDarwinSection();
 444     if (IDVal == ".text")
 445       // FIXME: This changes behavior based on the -static flag to the
 446       // assembler.
 447       return ParseDirectiveSectionSwitch("__TEXT", "__text",
 448                                      MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS);
 449     if (IDVal == ".const")
 450       return ParseDirectiveSectionSwitch("__TEXT", "__const");
 451     if (IDVal == ".static_const")
 452       return ParseDirectiveSectionSwitch("__TEXT", "__static_const");
 453     if (IDVal == ".cstring")
 454       return ParseDirectiveSectionSwitch("__TEXT","__cstring",
 455                                          MCSectionMachO::S_CSTRING_LITERALS);
 456     if (IDVal == ".literal4")
 457       return ParseDirectiveSectionSwitch("__TEXT", "__literal4",
 458                                          MCSectionMachO::S_4BYTE_LITERALS,
 459                                          4);
 460     if (IDVal == ".literal8")
 461       return ParseDirectiveSectionSwitch("__TEXT", "__literal8",
 462                                          MCSectionMachO::S_8BYTE_LITERALS,
 463                                          8);
 464     if (IDVal == ".literal16")
 465       return ParseDirectiveSectionSwitch("__TEXT","__literal16",
 466                                          MCSectionMachO::S_16BYTE_LITERALS,
 467                                          16);
 468     if (IDVal == ".constructor")
 469       return ParseDirectiveSectionSwitch("__TEXT","__constructor");
 470     if (IDVal == ".destructor")
 471       return ParseDirectiveSectionSwitch("__TEXT","__destructor");
 472     if (IDVal == ".fvmlib_init0")
 473       return ParseDirectiveSectionSwitch("__TEXT","__fvmlib_init0");
 474     if (IDVal == ".fvmlib_init1")
 475       return ParseDirectiveSectionSwitch("__TEXT","__fvmlib_init1");
 476
 477     // FIXME: The assembler manual claims that this has the self modify code
 478     // flag, at least on x86-32, but that does not appear to be correct.
 479     if (IDVal == ".symbol_stub")
 480       return ParseDirectiveSectionSwitch("__TEXT","__symbol_stub",
 481                                          MCSectionMachO::S_SYMBOL_STUBS |
 482                                        MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
 483                                           // FIXME: Different on PPC and ARM.
 484                                          0, 16);
 485     // FIXME: PowerPC only?
 486     if (IDVal == ".picsymbol_stub")
 487       return ParseDirectiveSectionSwitch("__TEXT","__picsymbol_stub",
 488                                          MCSectionMachO::S_SYMBOL_STUBS |
 489                                        MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
 490                                          0, 26);
 491     if (IDVal == ".data")
 492       return ParseDirectiveSectionSwitch("__DATA", "__data");
 493     if (IDVal == ".static_data")
 494       return ParseDirectiveSectionSwitch("__DATA", "__static_data");
 495
 496     // FIXME: The section names of these two are misspelled in the assembler
 497     // manual.
 498     if (IDVal == ".non_lazy_symbol_pointer")
 499       return ParseDirectiveSectionSwitch("__DATA", "__nl_symbol_ptr",
 500                                      MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
 501                                          4);
 502     if (IDVal == ".lazy_symbol_pointer")
 503       return ParseDirectiveSectionSwitch("__DATA", "__la_symbol_ptr",
 504                                          MCSectionMachO::S_LAZY_SYMBOL_POINTERS,
 505                                          4);
 506
 507     if (IDVal == ".dyld")
 508       return ParseDirectiveSectionSwitch("__DATA", "__dyld");
 509     if (IDVal == ".mod_init_func")
 510       return ParseDirectiveSectionSwitch("__DATA", "__mod_init_func",
 511                                        MCSectionMachO::S_MOD_INIT_FUNC_POINTERS,
 512                                          4);
 513     if (IDVal == ".mod_term_func")
 514       return ParseDirectiveSectionSwitch("__DATA", "__mod_term_func",
 515                                        MCSectionMachO::S_MOD_TERM_FUNC_POINTERS,
 516                                          4);
 517     if (IDVal == ".const_data")
 518       return ParseDirectiveSectionSwitch("__DATA", "__const");
 519
 520
 521     if (IDVal == ".objc_class")
 522       return ParseDirectiveSectionSwitch("__OBJC", "__class",
 523                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 524     if (IDVal == ".objc_meta_class")
 525       return ParseDirectiveSectionSwitch("__OBJC", "__meta_class",
 526                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 527     if (IDVal == ".objc_cat_cls_meth")
 528       return ParseDirectiveSectionSwitch("__OBJC", "__cat_cls_meth",
 529                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 530     if (IDVal == ".objc_cat_inst_meth")
 531       return ParseDirectiveSectionSwitch("__OBJC", "__cat_inst_meth",
 532                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 533     if (IDVal == ".objc_protocol")
 534       return ParseDirectiveSectionSwitch("__OBJC", "__protocol",
 535                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 536     if (IDVal == ".objc_string_object")
 537       return ParseDirectiveSectionSwitch("__OBJC", "__string_object",
 538                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 539     if (IDVal == ".objc_cls_meth")
 540       return ParseDirectiveSectionSwitch("__OBJC", "__cls_meth",
 541                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 542     if (IDVal == ".objc_inst_meth")
 543       return ParseDirectiveSectionSwitch("__OBJC", "__inst_meth",
 544                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 545     if (IDVal == ".objc_cls_refs")
 546       return ParseDirectiveSectionSwitch("__OBJC", "__cls_refs",
 547                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP |
 548                                          MCSectionMachO::S_LITERAL_POINTERS,
 549                                          4);
 550     if (IDVal == ".objc_message_refs")
 551       return ParseDirectiveSectionSwitch("__OBJC", "__message_refs",
 552                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP |
 553                                          MCSectionMachO::S_LITERAL_POINTERS,
 554                                          4);
 555     if (IDVal == ".objc_symbols")
 556       return ParseDirectiveSectionSwitch("__OBJC", "__symbols",
 557                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 558     if (IDVal == ".objc_category")
 559       return ParseDirectiveSectionSwitch("__OBJC", "__category",
 560                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 561     if (IDVal == ".objc_class_vars")
 562       return ParseDirectiveSectionSwitch("__OBJC", "__class_vars",
 563                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 564     if (IDVal == ".objc_instance_vars")
 565       return ParseDirectiveSectionSwitch("__OBJC", "__instance_vars",
 566                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 567     if (IDVal == ".objc_module_info")
 568       return ParseDirectiveSectionSwitch("__OBJC", "__module_info",
 569                                          MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
 570     if (IDVal == ".objc_class_names")
 571       return ParseDirectiveSectionSwitch("__TEXT", "__cstring",
 572                                          MCSectionMachO::S_CSTRING_LITERALS);
 573     if (IDVal == ".objc_meth_var_types")
 574       return ParseDirectiveSectionSwitch("__TEXT", "__cstring",
 575                                          MCSectionMachO::S_CSTRING_LITERALS);
 576     if (IDVal == ".objc_meth_var_names")
 577       return ParseDirectiveSectionSwitch("__TEXT", "__cstring",
 578                                          MCSectionMachO::S_CSTRING_LITERALS);
 579     if (IDVal == ".objc_selector_strs")
 580       return ParseDirectiveSectionSwitch("__OBJC", "__selector_strs",
 581                                          MCSectionMachO::S_CSTRING_LITERALS);
 582
 583     // Assembler features
 584     if (IDVal == ".set")
 585       return ParseDirectiveSet();
 586
 587     // Data directives
 588
 589     if (IDVal == ".ascii")
 590       return ParseDirectiveAscii(false);
 591     if (IDVal == ".asciz")
 592       return ParseDirectiveAscii(true);
 593
 594     if (IDVal == ".byte")
 595       return ParseDirectiveValue(1);
 596     if (IDVal == ".short")
 597       return ParseDirectiveValue(2);
 598     if (IDVal == ".long")
 599       return ParseDirectiveValue(4);
 600     if (IDVal == ".quad")
 601       return ParseDirectiveValue(8);
 602
 603     // FIXME: Target hooks for IsPow2.
 604     if (IDVal == ".align")
 605       return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/1);
 606     if (IDVal == ".align32")
 607       return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/4);
 608     if (IDVal == ".balign")
 609       return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/1);
 610     if (IDVal == ".balignw")
 611       return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/2);
 612     if (IDVal == ".balignl")
 613       return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/4);
 614     if (IDVal == ".p2align")
 615       return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/1);
 616     if (IDVal == ".p2alignw")
 617       return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/2);
 618     if (IDVal == ".p2alignl")
 619       return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/4);
 620
 621     if (IDVal == ".org")
 622       return ParseDirectiveOrg();
 623
 624     if (IDVal == ".fill")
 625       return ParseDirectiveFill();
 626     if (IDVal == ".space")
 627       return ParseDirectiveSpace();
 628
 629     // Symbol attribute directives
 630
 631     if (IDVal == ".globl" || IDVal == ".global")
 632       return ParseDirectiveSymbolAttribute(MCStreamer::Global);
 633     if (IDVal == ".hidden")
 634       return ParseDirectiveSymbolAttribute(MCStreamer::Hidden);
 635     if (IDVal == ".indirect_symbol")
 636       return ParseDirectiveSymbolAttribute(MCStreamer::IndirectSymbol);
 637     if (IDVal == ".internal")
 638       return ParseDirectiveSymbolAttribute(MCStreamer::Internal);
 639     if (IDVal == ".lazy_reference")
 640       return ParseDirectiveSymbolAttribute(MCStreamer::LazyReference);
 641     if (IDVal == ".no_dead_strip")
 642       return ParseDirectiveSymbolAttribute(MCStreamer::NoDeadStrip);
 643     if (IDVal == ".private_extern")
 644       return ParseDirectiveSymbolAttribute(MCStreamer::PrivateExtern);
 645     if (IDVal == ".protected")
 646       return ParseDirectiveSymbolAttribute(MCStreamer::Protected);
 647     if (IDVal == ".reference")
 648       return ParseDirectiveSymbolAttribute(MCStreamer::Reference);
 649     if (IDVal == ".weak")
 650       return ParseDirectiveSymbolAttribute(MCStreamer::Weak);
 651     if (IDVal == ".weak_definition")
 652       return ParseDirectiveSymbolAttribute(MCStreamer::WeakDefinition);
 653     if (IDVal == ".weak_reference")
 654       return ParseDirectiveSymbolAttribute(MCStreamer::WeakReference);
 655
 656     if (IDVal == ".comm")
 657       return ParseDirectiveComm(/*IsLocal=*/false);
 658     if (IDVal == ".lcomm")
 659       return ParseDirectiveComm(/*IsLocal=*/true);
 660     if (IDVal == ".zerofill")
 661       return ParseDirectiveDarwinZerofill();
 662     if (IDVal == ".desc")
 663       return ParseDirectiveDarwinSymbolDesc();
 664     if (IDVal == ".lsym")
 665       return ParseDirectiveDarwinLsym();
 666
 667     if (IDVal == ".subsections_via_symbols")
 668       return ParseDirectiveDarwinSubsectionsViaSymbols();
 669     if (IDVal == ".abort")
 670       return ParseDirectiveAbort();
 671     if (IDVal == ".include")
 672       return ParseDirectiveInclude();
 673     if (IDVal == ".dump")
 674       return ParseDirectiveDarwinDumpOrLoad(IDLoc, /*IsDump=*/true);
 675     if (IDVal == ".load")
 676       return ParseDirectiveDarwinDumpOrLoad(IDLoc, /*IsLoad=*/false);
 677
 678     // Debugging directives
 679
 680     if (IDVal == ".file")
 681       return ParseDirectiveFile(IDLoc);
 682     if (IDVal == ".line")
 683       return ParseDirectiveLine(IDLoc);
 684     if (IDVal == ".loc")
 685       return ParseDirectiveLoc(IDLoc);
 686
 687     // Target hook for parsing target specific directives.
 688     if (!getTargetParser().ParseDirective(ID))
 689       return false;
 690
 691     Warning(IDLoc, "ignoring directive for now");
 692     EatToEndOfStatement();
 693     return false;
 694   }
 695
 696   MCInst Inst;
 697   if (getTargetParser().ParseInstruction(IDVal, Inst))
 698     return true;
 699
 700   if (Lexer.isNot(AsmToken::EndOfStatement))
 701     return TokError("unexpected token in argument list");
 702
 703   // Eat the end of statement marker.
 704   Lexer.Lex();
 705
 706   // Instruction is good, process it.
 707   Out.EmitInstruction(Inst);
 708
 709   // Skip to end of line for now.
 710   return false;
 711 }
 712
 713 bool AsmParser::ParseAssignment(const StringRef &Name) {
 714   // FIXME: Use better location, we should use proper tokens.
 715   SMLoc EqualLoc = Lexer.getLoc();
 716
 717   const MCExpr *Value;
 718   SMLoc StartLoc = Lexer.getLoc();
 719   if (ParseExpression(Value))
 720     return true;
 721
 722   if (Lexer.isNot(AsmToken::EndOfStatement))
 723     return TokError("unexpected token in assignment");
 724
 725   // Eat the end of statement marker.
 726   Lexer.Lex();
 727
 728   // Diagnose assignment to a label.
 729   //
 730   // FIXME: Diagnostics. Note the location of the definition as a label.
 731   // FIXME: Handle '.'.
 732   // FIXME: Diagnose assignment to protected identifier (e.g., register name).
 733   MCSymbol *Sym = CreateSymbol(Name);
 734   if (!Sym->isUndefined() && !Sym->isAbsolute())
 735     return Error(EqualLoc, "symbol has already been defined");
 736
 737   // Do the assignment.
 738   Out.EmitAssignment(Sym, Value);
 739
 740   return false;
 741 }
 742
 743 /// ParseIdentifier:
 744 ///   ::= identifier
 745 ///   ::= string
 746 bool AsmParser::ParseIdentifier(StringRef &Res) {
 747   if (Lexer.isNot(AsmToken::Identifier) &&
 748       Lexer.isNot(AsmToken::String))
 749     return true;
 750
 751   Res = Lexer.getTok().getIdentifier();
 752
 753   Lexer.Lex(); // Consume the identifier token.
 754
 755   return false;
 756 }
 757
 758 /// ParseDirectiveSet:
 759 ///   ::= .set identifier ',' expression
 760 bool AsmParser::ParseDirectiveSet() {
 761   StringRef Name;
 762
 763   if (ParseIdentifier(Name))
 764     return TokError("expected identifier after '.set' directive");
 765
 766   if (Lexer.isNot(AsmToken::Comma))
 767     return TokError("unexpected token in '.set'");
 768   Lexer.Lex();
 769
 770   return ParseAssignment(Name);
 771 }
 772
 773 /// ParseDirectiveSection:
 774 ///   ::= .section identifier (',' identifier)*
 775 /// FIXME: This should actually parse out the segment, section, attributes and
 776 /// sizeof_stub fields.
 777 bool AsmParser::ParseDirectiveDarwinSection() {
 778   SMLoc Loc = Lexer.getLoc();
 779
 780   StringRef SectionName;
 781   if (ParseIdentifier(SectionName))
 782     return Error(Loc, "expected identifier after '.section' directive");
 783
 784   // Verify there is a following comma.
 785   if (!Lexer.is(AsmToken::Comma))
 786     return TokError("unexpected token in '.section' directive");
 787
 788   std::string SectionSpec = SectionName;
 789   SectionSpec += ",";
 790
 791   // Add all the tokens until the end of the line, ParseSectionSpecifier will
 792   // handle this.
 793   StringRef EOL = Lexer.LexUntilEndOfStatement();
 794   SectionSpec.append(EOL.begin(), EOL.end());
 795
 796   Lexer.Lex();
 797   if (Lexer.isNot(AsmToken::EndOfStatement))
 798     return TokError("unexpected token in '.section' directive");
 799   Lexer.Lex();
 800
 801
 802   StringRef Segment, Section;
 803   unsigned TAA, StubSize;
 804   std::string ErrorStr =
 805     MCSectionMachO::ParseSectionSpecifier(SectionSpec, Segment, Section,
 806                                           TAA, StubSize);
 807
 808   if (!ErrorStr.empty())
 809     return Error(Loc, ErrorStr.c_str());
 810
 811   // FIXME: Arch specific.
 812   Out.SwitchSection(getMachOSection(Segment, Section, TAA, StubSize,
 813                                     SectionKind()));
 814   return false;
 815 }
 816
 817 /// ParseDirectiveSectionSwitch -
 818 bool AsmParser::ParseDirectiveSectionSwitch(const char *Segment,
 819                                             const char *Section,
 820                                             unsigned TAA, unsigned Align,
 821                                             unsigned StubSize) {
 822   if (Lexer.isNot(AsmToken::EndOfStatement))
 823     return TokError("unexpected token in section switching directive");
 824   Lexer.Lex();
 825
 826   // FIXME: Arch specific.
 827   Out.SwitchSection(getMachOSection(Segment, Section, TAA, StubSize,
 828                                     SectionKind()));
 829
 830   // Set the implicit alignment, if any.
 831   //
 832   // FIXME: This isn't really what 'as' does; I think it just uses the implicit
 833   // alignment on the section (e.g., if one manually inserts bytes into the
 834   // section, then just issueing the section switch directive will not realign
 835   // the section. However, this is arguably more reasonable behavior, and there
 836   // is no good reason for someone to intentionally emit incorrectly sized
 837   // values into the implicitly aligned sections.
 838   if (Align)
 839     Out.EmitValueToAlignment(Align, 0, 1, 0);
 840
 841   return false;
 842 }
 843
 844 bool AsmParser::ParseEscapedString(std::string &Data) {
 845   assert(Lexer.is(AsmToken::String) && "Unexpected current token!");
 846
 847   Data = "";
 848   StringRef Str = Lexer.getTok().getStringContents();
 849   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 850     if (Str[i] != '\\') {
 851       Data += Str[i];
 852       continue;
 853     }
 854
 855     // Recognize escaped characters. Note that this escape semantics currently
 856     // loosely follows Darwin 'as'. Notably, it doesn't support hex escapes.
 857     ++i;
 858     if (i == e)
 859       return TokError("unexpected backslash at end of string");
 860
 861     // Recognize octal sequences.
 862     if ((unsigned) (Str[i] - '0') <= 7) {
 863       // Consume up to three octal characters.
 864       unsigned Value = Str[i] - '0';
 865
 866       if (i + 1 != e && ((unsigned) (Str[i + 1] - '0')) <= 7) {
 867         ++i;
 868         Value = Value * 8 + (Str[i] - '0');
 869
 870         if (i + 1 != e && ((unsigned) (Str[i + 1] - '0')) <= 7) {
 871           ++i;
 872           Value = Value * 8 + (Str[i] - '0');
 873         }
 874       }
 875
 876       if (Value > 255)
 877         return TokError("invalid octal escape sequence (out of range)");
 878
 879       Data += (unsigned char) Value;
 880       continue;
 881     }
 882
 883     // Otherwise recognize individual escapes.
 884     switch (Str[i]) {
 885     default:
 886       // Just reject invalid escape sequences for now.
 887       return TokError("invalid escape sequence (unrecognized character)");
 888
 889     case 'b': Data += '\b'; break;
 890     case 'f': Data += '\f'; break;
 891     case 'n': Data += '\n'; break;
 892     case 'r': Data += '\r'; break;
 893     case 't': Data += '\t'; break;
 894     case '"': Data += '"'; break;
 895     case '\\': Data += '\\'; break;
 896     }
 897   }
 898
 899   return false;
 900 }
 901
 902 /// ParseDirectiveAscii:
 903 ///   ::= ( .ascii | .asciz ) [ "string" ( , "string" )* ]
 904 bool AsmParser::ParseDirectiveAscii(bool ZeroTerminated) {
 905   if (Lexer.isNot(AsmToken::EndOfStatement)) {
 906     for (;;) {
 907       if (Lexer.isNot(AsmToken::String))
 908         return TokError("expected string in '.ascii' or '.asciz' directive");
 909
 910       std::string Data;
 911       if (ParseEscapedString(Data))
 912         return true;
 913
 914       Out.EmitBytes(Data);
 915       if (ZeroTerminated)
 916         Out.EmitBytes(StringRef("\0", 1));
 917
 918       Lexer.Lex();
 919
 920       if (Lexer.is(AsmToken::EndOfStatement))
 921         break;
 922
 923       if (Lexer.isNot(AsmToken::Comma))
 924         return TokError("unexpected token in '.ascii' or '.asciz' directive");
 925       Lexer.Lex();
 926     }
 927   }
 928
 929   Lexer.Lex();
 930   return false;
 931 }
 932
 933 /// ParseDirectiveValue
 934 ///  ::= (.byte | .short | ... ) [ expression (, expression)* ]
 935 bool AsmParser::ParseDirectiveValue(unsigned Size) {
 936   if (Lexer.isNot(AsmToken::EndOfStatement)) {
 937     for (;;) {
 938       const MCExpr *Value;
 939       SMLoc StartLoc = Lexer.getLoc();
 940       if (ParseExpression(Value))
 941         return true;
 942
 943       Out.EmitValue(Value, Size);
 944
 945       if (Lexer.is(AsmToken::EndOfStatement))
 946         break;
 947
 948       // FIXME: Improve diagnostic.
 949       if (Lexer.isNot(AsmToken::Comma))
 950         return TokError("unexpected token in directive");
 951       Lexer.Lex();
 952     }
 953   }
 954
 955   Lexer.Lex();
 956   return false;
 957 }
 958
 959 /// ParseDirectiveSpace
 960 ///  ::= .space expression [ , expression ]
 961 bool AsmParser::ParseDirectiveSpace() {
 962   int64_t NumBytes;
 963   if (ParseAbsoluteExpression(NumBytes))
 964     return true;
 965
 966   int64_t FillExpr = 0;
 967   bool HasFillExpr = false;
 968   if (Lexer.isNot(AsmToken::EndOfStatement)) {
 969     if (Lexer.isNot(AsmToken::Comma))
 970       return TokError("unexpected token in '.space' directive");
 971     Lexer.Lex();
 972
 973     if (ParseAbsoluteExpression(FillExpr))
 974       return true;
 975
 976     HasFillExpr = true;
 977
 978     if (Lexer.isNot(AsmToken::EndOfStatement))
 979       return TokError("unexpected token in '.space' directive");
 980   }
 981
 982   Lexer.Lex();
 983
 984   if (NumBytes <= 0)
 985     return TokError("invalid number of bytes in '.space' directive");
 986
 987   // FIXME: Sometimes the fill expr is 'nop' if it isn't supplied, instead of 0.
 988   for (uint64_t i = 0, e = NumBytes; i != e; ++i)
 989     Out.EmitValue(MCConstantExpr::Create(FillExpr, getContext()), 1);
 990
 991   return false;
 992 }
 993
 994 /// ParseDirectiveFill
 995 ///  ::= .fill expression , expression , expression
 996 bool AsmParser::ParseDirectiveFill() {
 997   int64_t NumValues;
 998   if (ParseAbsoluteExpression(NumValues))
 999     return true;
1000
1001   if (Lexer.isNot(AsmToken::Comma))
1002     return TokError("unexpected token in '.fill' directive");
1003   Lexer.Lex();
1004
1005   int64_t FillSize;
1006   if (ParseAbsoluteExpression(FillSize))
1007     return true;
1008
1009   if (Lexer.isNot(AsmToken::Comma))
1010     return TokError("unexpected token in '.fill' directive");
1011   Lexer.Lex();
1012
1013   int64_t FillExpr;
1014   if (ParseAbsoluteExpression(FillExpr))
1015     return true;
1016
1017   if (Lexer.isNot(AsmToken::EndOfStatement))
1018     return TokError("unexpected token in '.fill' directive");
1019
1020   Lexer.Lex();
1021
1022   if (FillSize != 1 && FillSize != 2 && FillSize != 4 && FillSize != 8)
1023     return TokError("invalid '.fill' size, expected 1, 2, 4, or 8");
1024
1025   for (uint64_t i = 0, e = NumValues; i != e; ++i)
1026     Out.EmitValue(MCConstantExpr::Create(FillExpr, getContext()), FillSize);
1027
1028   return false;
1029 }
1030
1031 /// ParseDirectiveOrg
1032 ///  ::= .org expression [ , expression ]
1033 bool AsmParser::ParseDirectiveOrg() {
1034   const MCExpr *Offset;
1035   SMLoc StartLoc = Lexer.getLoc();
1036   if (ParseExpression(Offset))
1037     return true;
1038
1039   // Parse optional fill expression.
1040   int64_t FillExpr = 0;
1041   if (Lexer.isNot(AsmToken::EndOfStatement)) {
1042     if (Lexer.isNot(AsmToken::Comma))
1043       return TokError("unexpected token in '.org' directive");
1044     Lexer.Lex();
1045
1046     if (ParseAbsoluteExpression(FillExpr))
1047       return true;
1048
1049     if (Lexer.isNot(AsmToken::EndOfStatement))
1050       return TokError("unexpected token in '.org' directive");
1051   }
1052
1053   Lexer.Lex();
1054
1055   // FIXME: Only limited forms of relocatable expressions are accepted here, it
1056   // has to be relative to the current section.
1057   Out.EmitValueToOffset(Offset, FillExpr);
1058
1059   return false;
1060 }
1061
1062 /// ParseDirectiveAlign
1063 ///  ::= {.align, ...} expression [ , expression [ , expression ]]
1064 bool AsmParser::ParseDirectiveAlign(bool IsPow2, unsigned ValueSize) {
1065   SMLoc AlignmentLoc = Lexer.getLoc();
1066   int64_t Alignment;
1067   if (ParseAbsoluteExpression(Alignment))
1068     return true;
1069
1070   SMLoc MaxBytesLoc;
1071   bool HasFillExpr = false;
1072   int64_t FillExpr = 0;
1073   int64_t MaxBytesToFill = 0;
1074   if (Lexer.isNot(AsmToken::EndOfStatement)) {
1075     if (Lexer.isNot(AsmToken::Comma))
1076       return TokError("unexpected token in directive");
1077     Lexer.Lex();
1078
1079     // The fill expression can be omitted while specifying a maximum number of
1080     // alignment bytes, e.g:
1081     //  .align 3,,4
1082     if (Lexer.isNot(AsmToken::Comma)) {
1083       HasFillExpr = true;
1084       if (ParseAbsoluteExpression(FillExpr))
1085         return true;
1086     }
1087
1088     if (Lexer.isNot(AsmToken::EndOfStatement)) {
1089       if (Lexer.isNot(AsmToken::Comma))
1090         return TokError("unexpected token in directive");
1091       Lexer.Lex();
1092
1093       MaxBytesLoc = Lexer.getLoc();
1094       if (ParseAbsoluteExpression(MaxBytesToFill))
1095         return true;
1096
1097       if (Lexer.isNot(AsmToken::EndOfStatement))
1098         return TokError("unexpected token in directive");
1099     }
1100   }
1101
1102   Lexer.Lex();
1103
1104   if (!HasFillExpr) {
1105     // FIXME: Sometimes fill with nop.
1106     FillExpr = 0;
1107   }
1108
1109   // Compute alignment in bytes.
1110   if (IsPow2) {
1111     // FIXME: Diagnose overflow.
1112     if (Alignment >= 32) {
1113       Error(AlignmentLoc, "invalid alignment value");
1114       Alignment = 31;
1115     }
1116
1117     Alignment = 1ULL << Alignment;
1118   }
1119
1120   // Diagnose non-sensical max bytes to align.
1121   if (MaxBytesLoc.isValid()) {
1122     if (MaxBytesToFill < 1) {
1123       Error(MaxBytesLoc, "alignment directive can never be satisfied in this "
1124             "many bytes, ignoring maximum bytes expression");
1125       MaxBytesToFill = 0;
1126     }
1127
1128     if (MaxBytesToFill >= Alignment) {
1129       Warning(MaxBytesLoc, "maximum bytes expression exceeds alignment and "
1130               "has no effect");
1131       MaxBytesToFill = 0;
1132     }
1133   }
1134
1135   // FIXME: Target specific behavior about how the "extra" bytes are filled.
1136   Out.EmitValueToAlignment(Alignment, FillExpr, ValueSize, MaxBytesToFill);
1137
1138   return false;
1139 }
1140
1141 /// ParseDirectiveSymbolAttribute
1142 ///  ::= { ".globl", ".weak", ... } [ identifier ( , identifier )* ]
1143 bool AsmParser::ParseDirectiveSymbolAttribute(MCStreamer::SymbolAttr Attr) {
1144   if (Lexer.isNot(AsmToken::EndOfStatement)) {
1145     for (;;) {
1146       StringRef Name;
1147
1148       if (ParseIdentifier(Name))
1149         return TokError("expected identifier in directive");
1150
1151       MCSymbol *Sym = CreateSymbol(Name);
1152
1153       Out.EmitSymbolAttribute(Sym, Attr);
1154
1155       if (Lexer.is(AsmToken::EndOfStatement))
1156         break;
1157
1158       if (Lexer.isNot(AsmToken::Comma))
1159         return TokError("unexpected token in directive");
1160       Lexer.Lex();
1161     }
1162   }
1163
1164   Lexer.Lex();
1165   return false;
1166 }
1167
1168 /// ParseDirectiveDarwinSymbolDesc
1169 ///  ::= .desc identifier , expression
1170 bool AsmParser::ParseDirectiveDarwinSymbolDesc() {
1171   StringRef Name;
1172   if (ParseIdentifier(Name))
1173     return TokError("expected identifier in directive");
1174
1175   // Handle the identifier as the key symbol.
1176   MCSymbol *Sym = CreateSymbol(Name);
1177
1178   if (Lexer.isNot(AsmToken::Comma))
1179     return TokError("unexpected token in '.desc' directive");
1180   Lexer.Lex();
1181
1182   SMLoc DescLoc = Lexer.getLoc();
1183   int64_t DescValue;
1184   if (ParseAbsoluteExpression(DescValue))
1185     return true;
1186
1187   if (Lexer.isNot(AsmToken::EndOfStatement))
1188     return TokError("unexpected token in '.desc' directive");
1189
1190   Lexer.Lex();
1191
1192   // Set the n_desc field of this Symbol to this DescValue
1193   Out.EmitSymbolDesc(Sym, DescValue);
1194
1195   return false;
1196 }
1197
1198 /// ParseDirectiveComm
1199 ///  ::= ( .comm | .lcomm ) identifier , size_expression [ , align_expression ]
1200 bool AsmParser::ParseDirectiveComm(bool IsLocal) {
1201   SMLoc IDLoc = Lexer.getLoc();
1202   StringRef Name;
1203   if (ParseIdentifier(Name))
1204     return TokError("expected identifier in directive");
1205
1206   // Handle the identifier as the key symbol.
1207   MCSymbol *Sym = CreateSymbol(Name);
1208
1209   if (Lexer.isNot(AsmToken::Comma))
1210     return TokError("unexpected token in directive");
1211   Lexer.Lex();
1212
1213   int64_t Size;
1214   SMLoc SizeLoc = Lexer.getLoc();
1215   if (ParseAbsoluteExpression(Size))
1216     return true;
1217
1218   int64_t Pow2Alignment = 0;
1219   SMLoc Pow2AlignmentLoc;
1220   if (Lexer.is(AsmToken::Comma)) {
1221     Lexer.Lex();
1222     Pow2AlignmentLoc = Lexer.getLoc();
1223     if (ParseAbsoluteExpression(Pow2Alignment))
1224       return true;
1225   }
1226
1227   if (Lexer.isNot(AsmToken::EndOfStatement))
1228     return TokError("unexpected token in '.comm' or '.lcomm' directive");
1229
1230   Lexer.Lex();
1231
1232   // NOTE: a size of zero for a .comm should create a undefined symbol
1233   // but a size of .lcomm creates a bss symbol of size zero.
1234   if (Size < 0)
1235     return Error(SizeLoc, "invalid '.comm' or '.lcomm' directive size, can't "
1236                  "be less than zero");
1237
1238   // NOTE: The alignment in the directive is a power of 2 value, the assember
1239   // may internally end up wanting an alignment in bytes.
1240   // FIXME: Diagnose overflow.
1241   if (Pow2Alignment < 0)
1242     return Error(Pow2AlignmentLoc, "invalid '.comm' or '.lcomm' directive "
1243                  "alignment, can't be less than zero");
1244
1245   if (!Sym->isUndefined())
1246     return Error(IDLoc, "invalid symbol redefinition");
1247
1248   // '.lcomm' is equivalent to '.zerofill'.
1249   // Create the Symbol as a common or local common with Size and Pow2Alignment
1250   if (IsLocal) {
1251     Out.EmitZerofill(getMachOSection("__DATA", "__bss",
1252                                      MCSectionMachO::S_ZEROFILL, 0,
1253                                      SectionKind()),
1254                      Sym, Size, 1 << Pow2Alignment);
1255     return false;
1256   }
1257
1258   Out.EmitCommonSymbol(Sym, Size, 1 << Pow2Alignment);
1259   return false;
1260 }
1261
1262 /// ParseDirectiveDarwinZerofill
1263 ///  ::= .zerofill segname , sectname [, identifier , size_expression [
1264 ///      , align_expression ]]
1265 bool AsmParser::ParseDirectiveDarwinZerofill() {
1266   // FIXME: Handle quoted names here.
1267
1268   if (Lexer.isNot(AsmToken::Identifier))
1269     return TokError("expected segment name after '.zerofill' directive");
1270   StringRef Segment = Lexer.getTok().getString();
1271   Lexer.Lex();
1272
1273   if (Lexer.isNot(AsmToken::Comma))
1274     return TokError("unexpected token in directive");
1275   Lexer.Lex();
1276
1277   if (Lexer.isNot(AsmToken::Identifier))
1278     return TokError("expected section name after comma in '.zerofill' "
1279                     "directive");
1280   StringRef Section = Lexer.getTok().getString();
1281   Lexer.Lex();
1282
1283   // If this is the end of the line all that was wanted was to create the
1284   // the section but with no symbol.
1285   if (Lexer.is(AsmToken::EndOfStatement)) {
1286     // Create the zerofill section but no symbol
1287     Out.EmitZerofill(getMachOSection(Segment, Section,
1288                                      MCSectionMachO::S_ZEROFILL, 0,
1289                                      SectionKind()));
1290     return false;
1291   }
1292
1293   if (Lexer.isNot(AsmToken::Comma))
1294     return TokError("unexpected token in directive");
1295   Lexer.Lex();
1296
1297   if (Lexer.isNot(AsmToken::Identifier))
1298     return TokError("expected identifier in directive");
1299
1300   // handle the identifier as the key symbol.
1301   SMLoc IDLoc = Lexer.getLoc();
1302   MCSymbol *Sym = CreateSymbol(Lexer.getTok().getString());
1303   Lexer.Lex();
1304
1305   if (Lexer.isNot(AsmToken::Comma))
1306     return TokError("unexpected token in directive");
1307   Lexer.Lex();
1308
1309   int64_t Size;
1310   SMLoc SizeLoc = Lexer.getLoc();
1311   if (ParseAbsoluteExpression(Size))
1312     return true;
1313
1314   int64_t Pow2Alignment = 0;
1315   SMLoc Pow2AlignmentLoc;
1316   if (Lexer.is(AsmToken::Comma)) {
1317     Lexer.Lex();
1318     Pow2AlignmentLoc = Lexer.getLoc();
1319     if (ParseAbsoluteExpression(Pow2Alignment))
1320       return true;
1321   }
1322
1323   if (Lexer.isNot(AsmToken::EndOfStatement))
1324     return TokError("unexpected token in '.zerofill' directive");
1325
1326   Lexer.Lex();
1327
1328   if (Size < 0)
1329     return Error(SizeLoc, "invalid '.zerofill' directive size, can't be less "
1330                  "than zero");
1331
1332   // NOTE: The alignment in the directive is a power of 2 value, the assember
1333   // may internally end up wanting an alignment in bytes.
1334   // FIXME: Diagnose overflow.
1335   if (Pow2Alignment < 0)
1336     return Error(Pow2AlignmentLoc, "invalid '.zerofill' directive alignment, "
1337                  "can't be less than zero");
1338
1339   if (!Sym->isUndefined())
1340     return Error(IDLoc, "invalid symbol redefinition");
1341
1342   // Create the zerofill Symbol with Size and Pow2Alignment
1343   //
1344   // FIXME: Arch specific.
1345   Out.EmitZerofill(getMachOSection(Segment, Section,
1346                                  MCSectionMachO::S_ZEROFILL, 0,
1347                                  SectionKind()),
1348                    Sym, Size, 1 << Pow2Alignment);
1349
1350   return false;
1351 }
1352
1353 /// ParseDirectiveDarwinSubsectionsViaSymbols
1354 ///  ::= .subsections_via_symbols
1355 bool AsmParser::ParseDirectiveDarwinSubsectionsViaSymbols() {
1356   if (Lexer.isNot(AsmToken::EndOfStatement))
1357     return TokError("unexpected token in '.subsections_via_symbols' directive");
1358
1359   Lexer.Lex();
1360
1361   Out.EmitAssemblerFlag(MCStreamer::SubsectionsViaSymbols);
1362
1363   return false;
1364 }
1365
1366 /// ParseDirectiveAbort
1367 ///  ::= .abort [ "abort_string" ]
1368 bool AsmParser::ParseDirectiveAbort() {
1369   // FIXME: Use loc from directive.
1370   SMLoc Loc = Lexer.getLoc();
1371
1372   StringRef Str = "";
1373   if (Lexer.isNot(AsmToken::EndOfStatement)) {
1374     if (Lexer.isNot(AsmToken::String))
1375       return TokError("expected string in '.abort' directive");
1376
1377     Str = Lexer.getTok().getString();
1378
1379     Lexer.Lex();
1380   }
1381
1382   if (Lexer.isNot(AsmToken::EndOfStatement))
1383     return TokError("unexpected token in '.abort' directive");
1384
1385   Lexer.Lex();
1386
1387   // FIXME: Handle here.
1388   if (Str.empty())
1389     Error(Loc, ".abort detected. Assembly stopping.");
1390   else
1391     Error(Loc, ".abort '" + Str + "' detected. Assembly stopping.");
1392
1393   return false;
1394 }
1395
1396 /// ParseDirectiveLsym
1397 ///  ::= .lsym identifier , expression
1398 bool AsmParser::ParseDirectiveDarwinLsym() {
1399   StringRef Name;
1400   if (ParseIdentifier(Name))
1401     return TokError("expected identifier in directive");
1402
1403   // Handle the identifier as the key symbol.
1404   MCSymbol *Sym = CreateSymbol(Name);
1405
1406   if (Lexer.isNot(AsmToken::Comma))
1407     return TokError("unexpected token in '.lsym' directive");
1408   Lexer.Lex();
1409
1410   const MCExpr *Value;
1411   SMLoc StartLoc = Lexer.getLoc();
1412   if (ParseExpression(Value))
1413     return true;
1414
1415   if (Lexer.isNot(AsmToken::EndOfStatement))
1416     return TokError("unexpected token in '.lsym' directive");
1417
1418   Lexer.Lex();
1419
1420   // We don't currently support this directive.
1421   //
1422   // FIXME: Diagnostic location!
1423   (void) Sym;
1424   return TokError("directive '.lsym' is unsupported");
1425 }
1426
1427 /// ParseDirectiveInclude
1428 ///  ::= .include "filename"
1429 bool AsmParser::ParseDirectiveInclude() {
1430   if (Lexer.isNot(AsmToken::String))
1431     return TokError("expected string in '.include' directive");
1432
1433   std::string Filename = Lexer.getTok().getString();
1434   SMLoc IncludeLoc = Lexer.getLoc();
1435   Lexer.Lex();
1436
1437   if (Lexer.isNot(AsmToken::EndOfStatement))
1438     return TokError("unexpected token in '.include' directive");
1439
1440   // Strip the quotes.
1441   Filename = Filename.substr(1, Filename.size()-2);
1442
1443   // Attempt to switch the lexer to the included file before consuming the end
1444   // of statement to avoid losing it when we switch.
1445   if (Lexer.EnterIncludeFile(Filename)) {
1446     Lexer.PrintMessage(IncludeLoc,
1447                        "Could not find include file '" + Filename + "'",
1448                        "error");
1449     return true;
1450   }
1451
1452   return false;
1453 }
1454
1455 /// ParseDirectiveDarwinDumpOrLoad
1456 ///  ::= ( .dump | .load ) "filename"
1457 bool AsmParser::ParseDirectiveDarwinDumpOrLoad(SMLoc IDLoc, bool IsDump) {
1458   if (Lexer.isNot(AsmToken::String))
1459     return TokError("expected string in '.dump' or '.load' directive");
1460
1461   Lexer.Lex();
1462
1463   if (Lexer.isNot(AsmToken::EndOfStatement))
1464     return TokError("unexpected token in '.dump' or '.load' directive");
1465
1466   Lexer.Lex();
1467
1468   // FIXME: If/when .dump and .load are implemented they will be done in the
1469   // the assembly parser and not have any need for an MCStreamer API.
1470   if (IsDump)
1471     Warning(IDLoc, "ignoring directive .dump for now");
1472   else
1473     Warning(IDLoc, "ignoring directive .load for now");
1474
1475   return false;
1476 }
1477
1478 /// ParseDirectiveIf
1479 /// ::= .if expression
1480 bool AsmParser::ParseDirectiveIf(SMLoc DirectiveLoc) {
1481   // Consume the identifier that was the .if directive
1482   Lexer.Lex();
1483
1484   TheCondStack.push_back(TheCondState);
1485   TheCondState.TheCond = AsmCond::IfCond;
1486   if(TheCondState.Ignore) {
1487     EatToEndOfStatement();
1488   }
1489   else {
1490     int64_t ExprValue;
1491     if (ParseAbsoluteExpression(ExprValue))
1492       return true;
1493
1494     if (Lexer.isNot(AsmToken::EndOfStatement))
1495       return TokError("unexpected token in '.if' directive");
1496
1497     Lexer.Lex();
1498
1499     TheCondState.CondMet = ExprValue;
1500     TheCondState.Ignore = !TheCondState.CondMet;
1501   }
1502
1503   return false;
1504 }
1505
1506 /// ParseDirectiveElseIf
1507 /// ::= .elseif expression
1508 bool AsmParser::ParseDirectiveElseIf(SMLoc DirectiveLoc) {
1509   if (TheCondState.TheCond != AsmCond::IfCond &&
1510       TheCondState.TheCond != AsmCond::ElseIfCond)
1511       Error(DirectiveLoc, "Encountered a .elseif that doesn't follow a .if or "
1512                           " an .elseif");
1513   TheCondState.TheCond = AsmCond::ElseIfCond;
1514
1515   // Consume the identifier that was the .elseif directive
1516   Lexer.Lex();
1517
1518   bool LastIgnoreState = false;
1519   if (!TheCondStack.empty())
1520       LastIgnoreState = TheCondStack.back().Ignore;
1521   if (LastIgnoreState || TheCondState.CondMet) {
1522     TheCondState.Ignore = true;
1523     EatToEndOfStatement();
1524   }
1525   else {
1526     int64_t ExprValue;
1527     if (ParseAbsoluteExpression(ExprValue))
1528       return true;
1529
1530     if (Lexer.isNot(AsmToken::EndOfStatement))
1531       return TokError("unexpected token in '.elseif' directive");
1532
1533     Lexer.Lex();
1534     TheCondState.CondMet = ExprValue;
1535     TheCondState.Ignore = !TheCondState.CondMet;
1536   }
1537
1538   return false;
1539 }
1540
1541 /// ParseDirectiveElse
1542 /// ::= .else
1543 bool AsmParser::ParseDirectiveElse(SMLoc DirectiveLoc) {
1544   // Consume the identifier that was the .else directive
1545   Lexer.Lex();
1546
1547   if (Lexer.isNot(AsmToken::EndOfStatement))
1548     return TokError("unexpected token in '.else' directive");
1549
1550   Lexer.Lex();
1551
1552   if (TheCondState.TheCond != AsmCond::IfCond &&
1553       TheCondState.TheCond != AsmCond::ElseIfCond)
1554       Error(DirectiveLoc, "Encountered a .else that doesn't follow a .if or an "
1555                           ".elseif");
1556   TheCondState.TheCond = AsmCond::ElseCond;
1557   bool LastIgnoreState = false;
1558   if (!TheCondStack.empty())
1559     LastIgnoreState = TheCondStack.back().Ignore;
1560   if (LastIgnoreState || TheCondState.CondMet)
1561     TheCondState.Ignore = true;
1562   else
1563     TheCondState.Ignore = false;
1564
1565   return false;
1566 }
1567
1568 /// ParseDirectiveEndIf
1569 /// ::= .endif
1570 bool AsmParser::ParseDirectiveEndIf(SMLoc DirectiveLoc) {
1571   // Consume the identifier that was the .endif directive
1572   Lexer.Lex();
1573
1574   if (Lexer.isNot(AsmToken::EndOfStatement))
1575     return TokError("unexpected token in '.endif' directive");
1576
1577   Lexer.Lex();
1578
1579   if ((TheCondState.TheCond == AsmCond::NoCond) ||
1580       TheCondStack.empty())
1581     Error(DirectiveLoc, "Encountered a .endif that doesn't follow a .if or "
1582                         ".else");
1583   if (!TheCondStack.empty()) {
1584     TheCondState = TheCondStack.back();
1585     TheCondStack.pop_back();
1586   }
1587
1588   return false;
1589 }
1590
1591 /// ParseDirectiveFile
1592 /// ::= .file [number] string
1593 bool AsmParser::ParseDirectiveFile(SMLoc DirectiveLoc) {
1594   // FIXME: I'm not sure what this is.
1595   int64_t FileNumber = -1;
1596   if (Lexer.is(AsmToken::Integer)) {
1597     FileNumber = Lexer.getTok().getIntVal();
1598     Lexer.Lex();
1599
1600     if (FileNumber < 1)
1601       return TokError("file number less than one");
1602   }
1603
1604   if (Lexer.isNot(AsmToken::String))
1605     return TokError("unexpected token in '.file' directive");
1606
1607   StringRef FileName = Lexer.getTok().getString();
1608   Lexer.Lex();
1609
1610   if (Lexer.isNot(AsmToken::EndOfStatement))
1611     return TokError("unexpected token in '.file' directive");
1612
1613   // FIXME: Do something with the .file.
1614
1615   return false;
1616 }
1617
1618 /// ParseDirectiveLine
1619 /// ::= .line [number]
1620 bool AsmParser::ParseDirectiveLine(SMLoc DirectiveLoc) {
1621   if (Lexer.isNot(AsmToken::EndOfStatement)) {
1622     if (Lexer.isNot(AsmToken::Integer))
1623       return TokError("unexpected token in '.line' directive");
1624
1625     int64_t LineNumber = Lexer.getTok().getIntVal();
1626     (void) LineNumber;
1627     Lexer.Lex();
1628
1629     // FIXME: Do something with the .line.
1630   }
1631
1632   if (Lexer.isNot(AsmToken::EndOfStatement))
1633     return TokError("unexpected token in '.file' directive");
1634
1635   return false;
1636 }
1637
1638
1639 /// ParseDirectiveLoc
1640 /// ::= .loc number [number [number]]
1641 bool AsmParser::ParseDirectiveLoc(SMLoc DirectiveLoc) {
1642   if (Lexer.isNot(AsmToken::Integer))
1643     return TokError("unexpected token in '.loc' directive");
1644
1645   // FIXME: What are these fields?
1646   int64_t FileNumber = Lexer.getTok().getIntVal();
1647   (void) FileNumber;
1648   // FIXME: Validate file.
1649
1650   Lexer.Lex();
1651   if (Lexer.isNot(AsmToken::EndOfStatement)) {
1652     if (Lexer.isNot(AsmToken::Integer))
1653       return TokError("unexpected token in '.loc' directive");
1654
1655     int64_t Param2 = Lexer.getTok().getIntVal();
1656     (void) Param2;
1657     Lexer.Lex();
1658
1659     if (Lexer.isNot(AsmToken::EndOfStatement)) {
1660       if (Lexer.isNot(AsmToken::Integer))
1661         return TokError("unexpected token in '.loc' directive");
1662
1663       int64_t Param3 = Lexer.getTok().getIntVal();
1664       (void) Param3;
1665       Lexer.Lex();
1666
1667       // FIXME: Do something with the .loc.
1668     }
1669   }
1670
1671   if (Lexer.isNot(AsmToken::EndOfStatement))
1672     return TokError("unexpected token in '.file' directive");
1673
1674   return false;
1675 }
1676