AsmParser.cpp revision 206274 
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 "llvm/MC/MCParser/AsmParser.h"
15#include "llvm/ADT/SmallString.h"
16#include "llvm/ADT/Twine.h"
17#include "llvm/MC/MCContext.h"
18#include "llvm/MC/MCExpr.h"
19#include "llvm/MC/MCInst.h"
20#include "llvm/MC/MCSectionMachO.h"
21#include "llvm/MC/MCStreamer.h"
22#include "llvm/MC/MCSymbol.h"
23#include "llvm/MC/MCParser/MCParsedAsmOperand.h"
24#include "llvm/Support/Compiler.h"
25#include "llvm/Support/SourceMgr.h"
26#include "llvm/Support/raw_ostream.h"
27#include "llvm/Target/TargetAsmParser.h"
28using namespace llvm;
29
30
31enum { DEFAULT_ADDRSPACE = 0 };
32
33// Mach-O section uniquing.
34//
35// FIXME: Figure out where this should live, it should be shared by
36// TargetLoweringObjectFile.
37typedef StringMap<const MCSectionMachO*> MachOUniqueMapTy;
38
39AsmParser::AsmParser(SourceMgr &_SM, MCContext &_Ctx, MCStreamer &_Out,
40                     const MCAsmInfo &_MAI)
41  : Lexer(_MAI), Ctx(_Ctx), Out(_Out), SrcMgr(_SM), TargetParser(0),
42    CurBuffer(0), SectionUniquingMap(0) {
43  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer));
44
45  // Debugging directives.
46  AddDirectiveHandler(".file", &AsmParser::ParseDirectiveFile);
47  AddDirectiveHandler(".line", &AsmParser::ParseDirectiveLine);
48  AddDirectiveHandler(".loc", &AsmParser::ParseDirectiveLoc);
49}
50
51
52
53AsmParser::~AsmParser() {
54  // If we have the MachO uniquing map, free it.
55  delete (MachOUniqueMapTy*)SectionUniquingMap;
56}
57
58const MCSection *AsmParser::getMachOSection(const StringRef &Segment,
59                                            const StringRef &Section,
60                                            unsigned TypeAndAttributes,
61                                            unsigned Reserved2,
62                                            SectionKind Kind) const {
63  // We unique sections by their segment/section pair.  The returned section
64  // may not have the same flags as the requested section, if so this should be
65  // diagnosed by the client as an error.
66
67  // Create the map if it doesn't already exist.
68  if (SectionUniquingMap == 0)
69    SectionUniquingMap = new MachOUniqueMapTy();
70  MachOUniqueMapTy &Map = *(MachOUniqueMapTy*)SectionUniquingMap;
71
72  // Form the name to look up.
73  SmallString<64> Name;
74  Name += Segment;
75  Name.push_back(',');
76  Name += Section;
77
78  // Do the lookup, if we have a hit, return it.
79  const MCSectionMachO *&Entry = Map[Name.str()];
80
81  // FIXME: This should validate the type and attributes.
82  if (Entry) return Entry;
83
84  // Otherwise, return a new section.
85  return Entry = MCSectionMachO::Create(Segment, Section, TypeAndAttributes,
86                                        Reserved2, Kind, Ctx);
87}
88
89void AsmParser::Warning(SMLoc L, const Twine &Msg) {
90  PrintMessage(L, Msg.str(), "warning");
91}
92
93bool AsmParser::Error(SMLoc L, const Twine &Msg) {
94  PrintMessage(L, Msg.str(), "error");
95  return true;
96}
97
98bool AsmParser::TokError(const char *Msg) {
99  PrintMessage(Lexer.getLoc(), Msg, "error");
100  return true;
101}
102
103void AsmParser::PrintMessage(SMLoc Loc, const std::string &Msg,
104                             const char *Type) const {
105  SrcMgr.PrintMessage(Loc, Msg, Type);
106}
107
108bool AsmParser::EnterIncludeFile(const std::string &Filename) {
109  int NewBuf = SrcMgr.AddIncludeFile(Filename, Lexer.getLoc());
110  if (NewBuf == -1)
111    return true;
112
113  CurBuffer = NewBuf;
114
115  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer));
116
117  return false;
118}
119
120const AsmToken &AsmParser::Lex() {
121  const AsmToken *tok = &Lexer.Lex();
122
123  if (tok->is(AsmToken::Eof)) {
124    // If this is the end of an included file, pop the parent file off the
125    // include stack.
126    SMLoc ParentIncludeLoc = SrcMgr.getParentIncludeLoc(CurBuffer);
127    if (ParentIncludeLoc != SMLoc()) {
128      CurBuffer = SrcMgr.FindBufferContainingLoc(ParentIncludeLoc);
129      Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer),
130                      ParentIncludeLoc.getPointer());
131      tok = &Lexer.Lex();
132    }
133  }
134
135  if (tok->is(AsmToken::Error))
136    PrintMessage(Lexer.getErrLoc(), Lexer.getErr(), "error");
137
138  return *tok;
139}
140
141bool AsmParser::Run(bool NoInitialTextSection, bool NoFinalize) {
142  // Create the initial section, if requested.
143  //
144  // FIXME: Target hook & command line option for initial section.
145  if (!NoInitialTextSection)
146    Out.SwitchSection(getMachOSection("__TEXT", "__text",
147                                      MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
148                                      0, SectionKind::getText()));
149
150  // Prime the lexer.
151  Lex();
152
153  bool HadError = false;
154
155  AsmCond StartingCondState = TheCondState;
156
157  // While we have input, parse each statement.
158  while (Lexer.isNot(AsmToken::Eof)) {
159    // Handle conditional assembly here before calling ParseStatement()
160    if (Lexer.getKind() == AsmToken::Identifier) {
161      // If we have an identifier, handle it as the key symbol.
162      AsmToken ID = getTok();
163      SMLoc IDLoc = ID.getLoc();
164      StringRef IDVal = ID.getString();
165
166      if (IDVal == ".if" ||
167          IDVal == ".elseif" ||
168          IDVal == ".else" ||
169          IDVal == ".endif") {
170        if (!ParseConditionalAssemblyDirectives(IDVal, IDLoc))
171          continue;
172	HadError = true;
173	EatToEndOfStatement();
174	continue;
175      }
176    }
177    if (TheCondState.Ignore) {
178      EatToEndOfStatement();
179      continue;
180    }
181
182    if (!ParseStatement()) continue;
183
184    // We had an error, remember it and recover by skipping to the next line.
185    HadError = true;
186    EatToEndOfStatement();
187  }
188
189  if (TheCondState.TheCond != StartingCondState.TheCond ||
190      TheCondState.Ignore != StartingCondState.Ignore)
191    return TokError("unmatched .ifs or .elses");
192
193  // Finalize the output stream if there are no errors and if the client wants
194  // us to.
195  if (!HadError && !NoFinalize)
196    Out.Finish();
197
198  return HadError;
199}
200
201/// ParseConditionalAssemblyDirectives - parse the conditional assembly
202/// directives
203bool AsmParser::ParseConditionalAssemblyDirectives(StringRef Directive,
204                                                   SMLoc DirectiveLoc) {
205  if (Directive == ".if")
206    return ParseDirectiveIf(DirectiveLoc);
207  if (Directive == ".elseif")
208    return ParseDirectiveElseIf(DirectiveLoc);
209  if (Directive == ".else")
210    return ParseDirectiveElse(DirectiveLoc);
211  if (Directive == ".endif")
212    return ParseDirectiveEndIf(DirectiveLoc);
213  return true;
214}
215
216/// EatToEndOfStatement - Throw away the rest of the line for testing purposes.
217void AsmParser::EatToEndOfStatement() {
218  while (Lexer.isNot(AsmToken::EndOfStatement) &&
219         Lexer.isNot(AsmToken::Eof))
220    Lex();
221
222  // Eat EOL.
223  if (Lexer.is(AsmToken::EndOfStatement))
224    Lex();
225}
226
227
228/// ParseParenExpr - Parse a paren expression and return it.
229/// NOTE: This assumes the leading '(' has already been consumed.
230///
231/// parenexpr ::= expr)
232///
233bool AsmParser::ParseParenExpr(const MCExpr *&Res, SMLoc &EndLoc) {
234  if (ParseExpression(Res)) return true;
235  if (Lexer.isNot(AsmToken::RParen))
236    return TokError("expected ')' in parentheses expression");
237  EndLoc = Lexer.getLoc();
238  Lex();
239  return false;
240}
241
242MCSymbol *AsmParser::CreateSymbol(StringRef Name) {
243  // FIXME: Inline into callers.
244  return Ctx.GetOrCreateSymbol(Name);
245}
246
247/// ParsePrimaryExpr - Parse a primary expression and return it.
248///  primaryexpr ::= (parenexpr
249///  primaryexpr ::= symbol
250///  primaryexpr ::= number
251///  primaryexpr ::= ~,+,- primaryexpr
252bool AsmParser::ParsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
253  switch (Lexer.getKind()) {
254  default:
255    return TokError("unknown token in expression");
256  case AsmToken::Exclaim:
257    Lex(); // Eat the operator.
258    if (ParsePrimaryExpr(Res, EndLoc))
259      return true;
260    Res = MCUnaryExpr::CreateLNot(Res, getContext());
261    return false;
262  case AsmToken::String:
263  case AsmToken::Identifier: {
264    // This is a symbol reference.
265    std::pair<StringRef, StringRef> Split = getTok().getIdentifier().split('@');
266    MCSymbol *Sym = CreateSymbol(Split.first);
267
268    // Lookup the symbol variant if used.
269    MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
270    if (Split.first.size() != getTok().getIdentifier().size())
271      Variant = MCSymbolRefExpr::getVariantKindForName(Split.second);
272
273    EndLoc = Lexer.getLoc();
274    Lex(); // Eat identifier.
275
276    // If this is an absolute variable reference, substitute it now to preserve
277    // semantics in the face of reassignment.
278    if (Sym->getValue() && isa<MCConstantExpr>(Sym->getValue())) {
279      if (Variant)
280        return Error(EndLoc, "unexpected modified on variable reference");
281
282      Res = Sym->getValue();
283      return false;
284    }
285
286    // Otherwise create a symbol ref.
287    Res = MCSymbolRefExpr::Create(Sym, Variant, getContext());
288    return false;
289  }
290  case AsmToken::Integer:
291    Res = MCConstantExpr::Create(getTok().getIntVal(), getContext());
292    EndLoc = Lexer.getLoc();
293    Lex(); // Eat token.
294    return false;
295  case AsmToken::LParen:
296    Lex(); // Eat the '('.
297    return ParseParenExpr(Res, EndLoc);
298  case AsmToken::Minus:
299    Lex(); // Eat the operator.
300    if (ParsePrimaryExpr(Res, EndLoc))
301      return true;
302    Res = MCUnaryExpr::CreateMinus(Res, getContext());
303    return false;
304  case AsmToken::Plus:
305    Lex(); // Eat the operator.
306    if (ParsePrimaryExpr(Res, EndLoc))
307      return true;
308    Res = MCUnaryExpr::CreatePlus(Res, getContext());
309    return false;
310  case AsmToken::Tilde:
311    Lex(); // Eat the operator.
312    if (ParsePrimaryExpr(Res, EndLoc))
313      return true;
314    Res = MCUnaryExpr::CreateNot(Res, getContext());
315    return false;
316  }
317}
318
319bool AsmParser::ParseExpression(const MCExpr *&Res) {
320  SMLoc EndLoc;
321  return ParseExpression(Res, EndLoc);
322}
323
324/// ParseExpression - Parse an expression and return it.
325///
326///  expr ::= expr +,- expr          -> lowest.
327///  expr ::= expr |,^,&,! expr      -> middle.
328///  expr ::= expr *,/,%,<<,>> expr  -> highest.
329///  expr ::= primaryexpr
330///
331bool AsmParser::ParseExpression(const MCExpr *&Res, SMLoc &EndLoc) {
332  // Parse the expression.
333  Res = 0;
334  if (ParsePrimaryExpr(Res, EndLoc) || ParseBinOpRHS(1, Res, EndLoc))
335    return true;
336
337  // Try to constant fold it up front, if possible.
338  int64_t Value;
339  if (Res->EvaluateAsAbsolute(Value))
340    Res = MCConstantExpr::Create(Value, getContext());
341
342  return false;
343}
344
345bool AsmParser::ParseParenExpression(const MCExpr *&Res, SMLoc &EndLoc) {
346  Res = 0;
347  return ParseParenExpr(Res, EndLoc) ||
348         ParseBinOpRHS(1, Res, EndLoc);
349}
350
351bool AsmParser::ParseAbsoluteExpression(int64_t &Res) {
352  const MCExpr *Expr;
353
354  SMLoc StartLoc = Lexer.getLoc();
355  if (ParseExpression(Expr))
356    return true;
357
358  if (!Expr->EvaluateAsAbsolute(Res))
359    return Error(StartLoc, "expected absolute expression");
360
361  return false;
362}
363
364static unsigned getBinOpPrecedence(AsmToken::TokenKind K,
365                                   MCBinaryExpr::Opcode &Kind) {
366  switch (K) {
367  default:
368    return 0;    // not a binop.
369
370    // Lowest Precedence: &&, ||
371  case AsmToken::AmpAmp:
372    Kind = MCBinaryExpr::LAnd;
373    return 1;
374  case AsmToken::PipePipe:
375    Kind = MCBinaryExpr::LOr;
376    return 1;
377
378    // Low Precedence: +, -, ==, !=, <>, <, <=, >, >=
379  case AsmToken::Plus:
380    Kind = MCBinaryExpr::Add;
381    return 2;
382  case AsmToken::Minus:
383    Kind = MCBinaryExpr::Sub;
384    return 2;
385  case AsmToken::EqualEqual:
386    Kind = MCBinaryExpr::EQ;
387    return 2;
388  case AsmToken::ExclaimEqual:
389  case AsmToken::LessGreater:
390    Kind = MCBinaryExpr::NE;
391    return 2;
392  case AsmToken::Less:
393    Kind = MCBinaryExpr::LT;
394    return 2;
395  case AsmToken::LessEqual:
396    Kind = MCBinaryExpr::LTE;
397    return 2;
398  case AsmToken::Greater:
399    Kind = MCBinaryExpr::GT;
400    return 2;
401  case AsmToken::GreaterEqual:
402    Kind = MCBinaryExpr::GTE;
403    return 2;
404
405    // Intermediate Precedence: |, &, ^
406    //
407    // FIXME: gas seems to support '!' as an infix operator?
408  case AsmToken::Pipe:
409    Kind = MCBinaryExpr::Or;
410    return 3;
411  case AsmToken::Caret:
412    Kind = MCBinaryExpr::Xor;
413    return 3;
414  case AsmToken::Amp:
415    Kind = MCBinaryExpr::And;
416    return 3;
417
418    // Highest Precedence: *, /, %, <<, >>
419  case AsmToken::Star:
420    Kind = MCBinaryExpr::Mul;
421    return 4;
422  case AsmToken::Slash:
423    Kind = MCBinaryExpr::Div;
424    return 4;
425  case AsmToken::Percent:
426    Kind = MCBinaryExpr::Mod;
427    return 4;
428  case AsmToken::LessLess:
429    Kind = MCBinaryExpr::Shl;
430    return 4;
431  case AsmToken::GreaterGreater:
432    Kind = MCBinaryExpr::Shr;
433    return 4;
434  }
435}
436
437
438/// ParseBinOpRHS - Parse all binary operators with precedence >= 'Precedence'.
439/// Res contains the LHS of the expression on input.
440bool AsmParser::ParseBinOpRHS(unsigned Precedence, const MCExpr *&Res,
441                              SMLoc &EndLoc) {
442  while (1) {
443    MCBinaryExpr::Opcode Kind = MCBinaryExpr::Add;
444    unsigned TokPrec = getBinOpPrecedence(Lexer.getKind(), Kind);
445
446    // If the next token is lower precedence than we are allowed to eat, return
447    // successfully with what we ate already.
448    if (TokPrec < Precedence)
449      return false;
450
451    Lex();
452
453    // Eat the next primary expression.
454    const MCExpr *RHS;
455    if (ParsePrimaryExpr(RHS, EndLoc)) return true;
456
457    // If BinOp binds less tightly with RHS than the operator after RHS, let
458    // the pending operator take RHS as its LHS.
459    MCBinaryExpr::Opcode Dummy;
460    unsigned NextTokPrec = getBinOpPrecedence(Lexer.getKind(), Dummy);
461    if (TokPrec < NextTokPrec) {
462      if (ParseBinOpRHS(Precedence+1, RHS, EndLoc)) return true;
463    }
464
465    // Merge LHS and RHS according to operator.
466    Res = MCBinaryExpr::Create(Kind, Res, RHS, getContext());
467  }
468}
469
470
471
472
473/// ParseStatement:
474///   ::= EndOfStatement
475///   ::= Label* Directive ...Operands... EndOfStatement
476///   ::= Label* Identifier OperandList* EndOfStatement
477bool AsmParser::ParseStatement() {
478  if (Lexer.is(AsmToken::EndOfStatement)) {
479    Lex();
480    return false;
481  }
482
483  // Statements always start with an identifier.
484  AsmToken ID = getTok();
485  SMLoc IDLoc = ID.getLoc();
486  StringRef IDVal;
487  if (ParseIdentifier(IDVal))
488    return TokError("unexpected token at start of statement");
489
490  // FIXME: Recurse on local labels?
491
492  // See what kind of statement we have.
493  switch (Lexer.getKind()) {
494  case AsmToken::Colon: {
495    // identifier ':'   -> Label.
496    Lex();
497
498    // Diagnose attempt to use a variable as a label.
499    //
500    // FIXME: Diagnostics. Note the location of the definition as a label.
501    // FIXME: This doesn't diagnose assignment to a symbol which has been
502    // implicitly marked as external.
503    MCSymbol *Sym = CreateSymbol(IDVal);
504    if (!Sym->isUndefined())
505      return Error(IDLoc, "invalid symbol redefinition");
506
507    // Emit the label.
508    Out.EmitLabel(Sym);
509
510    return ParseStatement();
511  }
512
513  case AsmToken::Equal:
514    // identifier '=' ... -> assignment statement
515    Lex();
516
517    return ParseAssignment(IDVal);
518
519  default: // Normal instruction or directive.
520    break;
521  }
522
523  // Otherwise, we have a normal instruction or directive.
524  if (IDVal[0] == '.') {
525    // FIXME: This should be driven based on a hash lookup and callback.
526    if (IDVal == ".section")
527      return ParseDirectiveDarwinSection();
528    if (IDVal == ".text")
529      // FIXME: This changes behavior based on the -static flag to the
530      // assembler.
531      return ParseDirectiveSectionSwitch("__TEXT", "__text",
532                                     MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS);
533    if (IDVal == ".const")
534      return ParseDirectiveSectionSwitch("__TEXT", "__const");
535    if (IDVal == ".static_const")
536      return ParseDirectiveSectionSwitch("__TEXT", "__static_const");
537    if (IDVal == ".cstring")
538      return ParseDirectiveSectionSwitch("__TEXT","__cstring",
539                                         MCSectionMachO::S_CSTRING_LITERALS);
540    if (IDVal == ".literal4")
541      return ParseDirectiveSectionSwitch("__TEXT", "__literal4",
542                                         MCSectionMachO::S_4BYTE_LITERALS,
543                                         4);
544    if (IDVal == ".literal8")
545      return ParseDirectiveSectionSwitch("__TEXT", "__literal8",
546                                         MCSectionMachO::S_8BYTE_LITERALS,
547                                         8);
548    if (IDVal == ".literal16")
549      return ParseDirectiveSectionSwitch("__TEXT","__literal16",
550                                         MCSectionMachO::S_16BYTE_LITERALS,
551                                         16);
552    if (IDVal == ".constructor")
553      return ParseDirectiveSectionSwitch("__TEXT","__constructor");
554    if (IDVal == ".destructor")
555      return ParseDirectiveSectionSwitch("__TEXT","__destructor");
556    if (IDVal == ".fvmlib_init0")
557      return ParseDirectiveSectionSwitch("__TEXT","__fvmlib_init0");
558    if (IDVal == ".fvmlib_init1")
559      return ParseDirectiveSectionSwitch("__TEXT","__fvmlib_init1");
560
561    // FIXME: The assembler manual claims that this has the self modify code
562    // flag, at least on x86-32, but that does not appear to be correct.
563    if (IDVal == ".symbol_stub")
564      return ParseDirectiveSectionSwitch("__TEXT","__symbol_stub",
565                                         MCSectionMachO::S_SYMBOL_STUBS |
566                                       MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
567                                          // FIXME: Different on PPC and ARM.
568                                         0, 16);
569    // FIXME: PowerPC only?
570    if (IDVal == ".picsymbol_stub")
571      return ParseDirectiveSectionSwitch("__TEXT","__picsymbol_stub",
572                                         MCSectionMachO::S_SYMBOL_STUBS |
573                                       MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
574                                         0, 26);
575    if (IDVal == ".data")
576      return ParseDirectiveSectionSwitch("__DATA", "__data");
577    if (IDVal == ".static_data")
578      return ParseDirectiveSectionSwitch("__DATA", "__static_data");
579
580    // FIXME: The section names of these two are misspelled in the assembler
581    // manual.
582    if (IDVal == ".non_lazy_symbol_pointer")
583      return ParseDirectiveSectionSwitch("__DATA", "__nl_symbol_ptr",
584                                     MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
585                                         4);
586    if (IDVal == ".lazy_symbol_pointer")
587      return ParseDirectiveSectionSwitch("__DATA", "__la_symbol_ptr",
588                                         MCSectionMachO::S_LAZY_SYMBOL_POINTERS,
589                                         4);
590
591    if (IDVal == ".dyld")
592      return ParseDirectiveSectionSwitch("__DATA", "__dyld");
593    if (IDVal == ".mod_init_func")
594      return ParseDirectiveSectionSwitch("__DATA", "__mod_init_func",
595                                       MCSectionMachO::S_MOD_INIT_FUNC_POINTERS,
596                                         4);
597    if (IDVal == ".mod_term_func")
598      return ParseDirectiveSectionSwitch("__DATA", "__mod_term_func",
599                                       MCSectionMachO::S_MOD_TERM_FUNC_POINTERS,
600                                         4);
601    if (IDVal == ".const_data")
602      return ParseDirectiveSectionSwitch("__DATA", "__const");
603
604
605    if (IDVal == ".objc_class")
606      return ParseDirectiveSectionSwitch("__OBJC", "__class",
607                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
608    if (IDVal == ".objc_meta_class")
609      return ParseDirectiveSectionSwitch("__OBJC", "__meta_class",
610                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
611    if (IDVal == ".objc_cat_cls_meth")
612      return ParseDirectiveSectionSwitch("__OBJC", "__cat_cls_meth",
613                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
614    if (IDVal == ".objc_cat_inst_meth")
615      return ParseDirectiveSectionSwitch("__OBJC", "__cat_inst_meth",
616                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
617    if (IDVal == ".objc_protocol")
618      return ParseDirectiveSectionSwitch("__OBJC", "__protocol",
619                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
620    if (IDVal == ".objc_string_object")
621      return ParseDirectiveSectionSwitch("__OBJC", "__string_object",
622                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
623    if (IDVal == ".objc_cls_meth")
624      return ParseDirectiveSectionSwitch("__OBJC", "__cls_meth",
625                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
626    if (IDVal == ".objc_inst_meth")
627      return ParseDirectiveSectionSwitch("__OBJC", "__inst_meth",
628                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
629    if (IDVal == ".objc_cls_refs")
630      return ParseDirectiveSectionSwitch("__OBJC", "__cls_refs",
631                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP |
632                                         MCSectionMachO::S_LITERAL_POINTERS,
633                                         4);
634    if (IDVal == ".objc_message_refs")
635      return ParseDirectiveSectionSwitch("__OBJC", "__message_refs",
636                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP |
637                                         MCSectionMachO::S_LITERAL_POINTERS,
638                                         4);
639    if (IDVal == ".objc_symbols")
640      return ParseDirectiveSectionSwitch("__OBJC", "__symbols",
641                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
642    if (IDVal == ".objc_category")
643      return ParseDirectiveSectionSwitch("__OBJC", "__category",
644                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
645    if (IDVal == ".objc_class_vars")
646      return ParseDirectiveSectionSwitch("__OBJC", "__class_vars",
647                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
648    if (IDVal == ".objc_instance_vars")
649      return ParseDirectiveSectionSwitch("__OBJC", "__instance_vars",
650                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
651    if (IDVal == ".objc_module_info")
652      return ParseDirectiveSectionSwitch("__OBJC", "__module_info",
653                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
654    if (IDVal == ".objc_class_names")
655      return ParseDirectiveSectionSwitch("__TEXT", "__cstring",
656                                         MCSectionMachO::S_CSTRING_LITERALS);
657    if (IDVal == ".objc_meth_var_types")
658      return ParseDirectiveSectionSwitch("__TEXT", "__cstring",
659                                         MCSectionMachO::S_CSTRING_LITERALS);
660    if (IDVal == ".objc_meth_var_names")
661      return ParseDirectiveSectionSwitch("__TEXT", "__cstring",
662                                         MCSectionMachO::S_CSTRING_LITERALS);
663    if (IDVal == ".objc_selector_strs")
664      return ParseDirectiveSectionSwitch("__OBJC", "__selector_strs",
665                                         MCSectionMachO::S_CSTRING_LITERALS);
666
667    // Assembler features
668    if (IDVal == ".set")
669      return ParseDirectiveSet();
670
671    // Data directives
672
673    if (IDVal == ".ascii")
674      return ParseDirectiveAscii(false);
675    if (IDVal == ".asciz")
676      return ParseDirectiveAscii(true);
677
678    if (IDVal == ".byte")
679      return ParseDirectiveValue(1);
680    if (IDVal == ".short")
681      return ParseDirectiveValue(2);
682    if (IDVal == ".long")
683      return ParseDirectiveValue(4);
684    if (IDVal == ".quad")
685      return ParseDirectiveValue(8);
686
687    // FIXME: Target hooks for IsPow2.
688    if (IDVal == ".align")
689      return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/1);
690    if (IDVal == ".align32")
691      return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/4);
692    if (IDVal == ".balign")
693      return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/1);
694    if (IDVal == ".balignw")
695      return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/2);
696    if (IDVal == ".balignl")
697      return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/4);
698    if (IDVal == ".p2align")
699      return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/1);
700    if (IDVal == ".p2alignw")
701      return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/2);
702    if (IDVal == ".p2alignl")
703      return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/4);
704
705    if (IDVal == ".org")
706      return ParseDirectiveOrg();
707
708    if (IDVal == ".fill")
709      return ParseDirectiveFill();
710    if (IDVal == ".space")
711      return ParseDirectiveSpace();
712
713    // Symbol attribute directives
714
715    if (IDVal == ".globl" || IDVal == ".global")
716      return ParseDirectiveSymbolAttribute(MCSA_Global);
717    if (IDVal == ".hidden")
718      return ParseDirectiveSymbolAttribute(MCSA_Hidden);
719    if (IDVal == ".indirect_symbol")
720      return ParseDirectiveSymbolAttribute(MCSA_IndirectSymbol);
721    if (IDVal == ".internal")
722      return ParseDirectiveSymbolAttribute(MCSA_Internal);
723    if (IDVal == ".lazy_reference")
724      return ParseDirectiveSymbolAttribute(MCSA_LazyReference);
725    if (IDVal == ".no_dead_strip")
726      return ParseDirectiveSymbolAttribute(MCSA_NoDeadStrip);
727    if (IDVal == ".private_extern")
728      return ParseDirectiveSymbolAttribute(MCSA_PrivateExtern);
729    if (IDVal == ".protected")
730      return ParseDirectiveSymbolAttribute(MCSA_Protected);
731    if (IDVal == ".reference")
732      return ParseDirectiveSymbolAttribute(MCSA_Reference);
733    if (IDVal == ".weak")
734      return ParseDirectiveSymbolAttribute(MCSA_Weak);
735    if (IDVal == ".weak_definition")
736      return ParseDirectiveSymbolAttribute(MCSA_WeakDefinition);
737    if (IDVal == ".weak_reference")
738      return ParseDirectiveSymbolAttribute(MCSA_WeakReference);
739
740    if (IDVal == ".comm")
741      return ParseDirectiveComm(/*IsLocal=*/false);
742    if (IDVal == ".lcomm")
743      return ParseDirectiveComm(/*IsLocal=*/true);
744    if (IDVal == ".zerofill")
745      return ParseDirectiveDarwinZerofill();
746    if (IDVal == ".desc")
747      return ParseDirectiveDarwinSymbolDesc();
748    if (IDVal == ".lsym")
749      return ParseDirectiveDarwinLsym();
750
751    if (IDVal == ".subsections_via_symbols")
752      return ParseDirectiveDarwinSubsectionsViaSymbols();
753    if (IDVal == ".abort")
754      return ParseDirectiveAbort();
755    if (IDVal == ".include")
756      return ParseDirectiveInclude();
757    if (IDVal == ".dump")
758      return ParseDirectiveDarwinDumpOrLoad(IDLoc, /*IsDump=*/true);
759    if (IDVal == ".load")
760      return ParseDirectiveDarwinDumpOrLoad(IDLoc, /*IsLoad=*/false);
761
762    // Look up the handler in the handler table,
763    bool(AsmParser::*Handler)(StringRef, SMLoc) = DirectiveMap[IDVal];
764    if (Handler)
765      return (this->*Handler)(IDVal, IDLoc);
766
767    // Target hook for parsing target specific directives.
768    if (!getTargetParser().ParseDirective(ID))
769      return false;
770
771    Warning(IDLoc, "ignoring directive for now");
772    EatToEndOfStatement();
773    return false;
774  }
775
776
777  SmallVector<MCParsedAsmOperand*, 8> ParsedOperands;
778  if (getTargetParser().ParseInstruction(IDVal, IDLoc, ParsedOperands))
779    // FIXME: Leaking ParsedOperands on failure.
780    return true;
781
782  if (Lexer.isNot(AsmToken::EndOfStatement))
783    // FIXME: Leaking ParsedOperands on failure.
784    return TokError("unexpected token in argument list");
785
786  // Eat the end of statement marker.
787  Lex();
788
789
790  MCInst Inst;
791
792  bool MatchFail = getTargetParser().MatchInstruction(ParsedOperands, Inst);
793
794  // Free any parsed operands.
795  for (unsigned i = 0, e = ParsedOperands.size(); i != e; ++i)
796    delete ParsedOperands[i];
797
798  if (MatchFail) {
799    // FIXME: We should give nicer diagnostics about the exact failure.
800    Error(IDLoc, "unrecognized instruction");
801    return true;
802  }
803
804  // Instruction is good, process it.
805  Out.EmitInstruction(Inst);
806
807  // Skip to end of line for now.
808  return false;
809}
810
811bool AsmParser::ParseAssignment(const StringRef &Name) {
812  // FIXME: Use better location, we should use proper tokens.
813  SMLoc EqualLoc = Lexer.getLoc();
814
815  const MCExpr *Value;
816  SMLoc StartLoc = Lexer.getLoc();
817  if (ParseExpression(Value))
818    return true;
819
820  if (Lexer.isNot(AsmToken::EndOfStatement))
821    return TokError("unexpected token in assignment");
822
823  // Eat the end of statement marker.
824  Lex();
825
826  // Validate that the LHS is allowed to be a variable (either it has not been
827  // used as a symbol, or it is an absolute symbol).
828  MCSymbol *Sym = getContext().LookupSymbol(Name);
829  if (Sym) {
830    // Diagnose assignment to a label.
831    //
832    // FIXME: Diagnostics. Note the location of the definition as a label.
833    // FIXME: Diagnose assignment to protected identifier (e.g., register name).
834    if (!Sym->isUndefined() && !Sym->isAbsolute())
835      return Error(EqualLoc, "redefinition of '" + Name + "'");
836    else if (!Sym->isVariable())
837      return Error(EqualLoc, "invalid assignment to '" + Name + "'");
838    else if (!isa<MCConstantExpr>(Sym->getValue()))
839      return Error(EqualLoc, "invalid reassignment of non-absolute variable '" +
840                   Name + "'");
841  } else
842    Sym = CreateSymbol(Name);
843
844  // FIXME: Handle '.'.
845
846  // Do the assignment.
847  Out.EmitAssignment(Sym, Value);
848
849  return false;
850}
851
852/// ParseIdentifier:
853///   ::= identifier
854///   ::= string
855bool AsmParser::ParseIdentifier(StringRef &Res) {
856  if (Lexer.isNot(AsmToken::Identifier) &&
857      Lexer.isNot(AsmToken::String))
858    return true;
859
860  Res = getTok().getIdentifier();
861
862  Lex(); // Consume the identifier token.
863
864  return false;
865}
866
867/// ParseDirectiveSet:
868///   ::= .set identifier ',' expression
869bool AsmParser::ParseDirectiveSet() {
870  StringRef Name;
871
872  if (ParseIdentifier(Name))
873    return TokError("expected identifier after '.set' directive");
874
875  if (Lexer.isNot(AsmToken::Comma))
876    return TokError("unexpected token in '.set'");
877  Lex();
878
879  return ParseAssignment(Name);
880}
881
882/// ParseDirectiveSection:
883///   ::= .section identifier (',' identifier)*
884/// FIXME: This should actually parse out the segment, section, attributes and
885/// sizeof_stub fields.
886bool AsmParser::ParseDirectiveDarwinSection() {
887  SMLoc Loc = Lexer.getLoc();
888
889  StringRef SectionName;
890  if (ParseIdentifier(SectionName))
891    return Error(Loc, "expected identifier after '.section' directive");
892
893  // Verify there is a following comma.
894  if (!Lexer.is(AsmToken::Comma))
895    return TokError("unexpected token in '.section' directive");
896
897  std::string SectionSpec = SectionName;
898  SectionSpec += ",";
899
900  // Add all the tokens until the end of the line, ParseSectionSpecifier will
901  // handle this.
902  StringRef EOL = Lexer.LexUntilEndOfStatement();
903  SectionSpec.append(EOL.begin(), EOL.end());
904
905  Lex();
906  if (Lexer.isNot(AsmToken::EndOfStatement))
907    return TokError("unexpected token in '.section' directive");
908  Lex();
909
910
911  StringRef Segment, Section;
912  unsigned TAA, StubSize;
913  std::string ErrorStr =
914    MCSectionMachO::ParseSectionSpecifier(SectionSpec, Segment, Section,
915                                          TAA, StubSize);
916
917  if (!ErrorStr.empty())
918    return Error(Loc, ErrorStr.c_str());
919
920  // FIXME: Arch specific.
921  bool isText = Segment == "__TEXT";  // FIXME: Hack.
922  Out.SwitchSection(getMachOSection(Segment, Section, TAA, StubSize,
923                                    isText ? SectionKind::getText()
924                                           : SectionKind::getDataRel()));
925  return false;
926}
927
928/// ParseDirectiveSectionSwitch -
929bool AsmParser::ParseDirectiveSectionSwitch(const char *Segment,
930                                            const char *Section,
931                                            unsigned TAA, unsigned Align,
932                                            unsigned StubSize) {
933  if (Lexer.isNot(AsmToken::EndOfStatement))
934    return TokError("unexpected token in section switching directive");
935  Lex();
936
937  // FIXME: Arch specific.
938  bool isText = StringRef(Segment) == "__TEXT";  // FIXME: Hack.
939  Out.SwitchSection(getMachOSection(Segment, Section, TAA, StubSize,
940                                    isText ? SectionKind::getText()
941                                    : SectionKind::getDataRel()));
942
943  // Set the implicit alignment, if any.
944  //
945  // FIXME: This isn't really what 'as' does; I think it just uses the implicit
946  // alignment on the section (e.g., if one manually inserts bytes into the
947  // section, then just issueing the section switch directive will not realign
948  // the section. However, this is arguably more reasonable behavior, and there
949  // is no good reason for someone to intentionally emit incorrectly sized
950  // values into the implicitly aligned sections.
951  if (Align)
952    Out.EmitValueToAlignment(Align, 0, 1, 0);
953
954  return false;
955}
956
957bool AsmParser::ParseEscapedString(std::string &Data) {
958  assert(Lexer.is(AsmToken::String) && "Unexpected current token!");
959
960  Data = "";
961  StringRef Str = getTok().getStringContents();
962  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
963    if (Str[i] != '\\') {
964      Data += Str[i];
965      continue;
966    }
967
968    // Recognize escaped characters. Note that this escape semantics currently
969    // loosely follows Darwin 'as'. Notably, it doesn't support hex escapes.
970    ++i;
971    if (i == e)
972      return TokError("unexpected backslash at end of string");
973
974    // Recognize octal sequences.
975    if ((unsigned) (Str[i] - '0') <= 7) {
976      // Consume up to three octal characters.
977      unsigned Value = Str[i] - '0';
978
979      if (i + 1 != e && ((unsigned) (Str[i + 1] - '0')) <= 7) {
980        ++i;
981        Value = Value * 8 + (Str[i] - '0');
982
983        if (i + 1 != e && ((unsigned) (Str[i + 1] - '0')) <= 7) {
984          ++i;
985          Value = Value * 8 + (Str[i] - '0');
986        }
987      }
988
989      if (Value > 255)
990        return TokError("invalid octal escape sequence (out of range)");
991
992      Data += (unsigned char) Value;
993      continue;
994    }
995
996    // Otherwise recognize individual escapes.
997    switch (Str[i]) {
998    default:
999      // Just reject invalid escape sequences for now.
1000      return TokError("invalid escape sequence (unrecognized character)");
1001
1002    case 'b': Data += '\b'; break;
1003    case 'f': Data += '\f'; break;
1004    case 'n': Data += '\n'; break;
1005    case 'r': Data += '\r'; break;
1006    case 't': Data += '\t'; break;
1007    case '"': Data += '"'; break;
1008    case '\\': Data += '\\'; break;
1009    }
1010  }
1011
1012  return false;
1013}
1014
1015/// ParseDirectiveAscii:
1016///   ::= ( .ascii | .asciz ) [ "string" ( , "string" )* ]
1017bool AsmParser::ParseDirectiveAscii(bool ZeroTerminated) {
1018  if (Lexer.isNot(AsmToken::EndOfStatement)) {
1019    for (;;) {
1020      if (Lexer.isNot(AsmToken::String))
1021        return TokError("expected string in '.ascii' or '.asciz' directive");
1022
1023      std::string Data;
1024      if (ParseEscapedString(Data))
1025        return true;
1026
1027      Out.EmitBytes(Data, DEFAULT_ADDRSPACE);
1028      if (ZeroTerminated)
1029        Out.EmitBytes(StringRef("\0", 1), DEFAULT_ADDRSPACE);
1030
1031      Lex();
1032
1033      if (Lexer.is(AsmToken::EndOfStatement))
1034        break;
1035
1036      if (Lexer.isNot(AsmToken::Comma))
1037        return TokError("unexpected token in '.ascii' or '.asciz' directive");
1038      Lex();
1039    }
1040  }
1041
1042  Lex();
1043  return false;
1044}
1045
1046/// ParseDirectiveValue
1047///  ::= (.byte | .short | ... ) [ expression (, expression)* ]
1048bool AsmParser::ParseDirectiveValue(unsigned Size) {
1049  if (Lexer.isNot(AsmToken::EndOfStatement)) {
1050    for (;;) {
1051      const MCExpr *Value;
1052      SMLoc ATTRIBUTE_UNUSED StartLoc = Lexer.getLoc();
1053      if (ParseExpression(Value))
1054        return true;
1055
1056      Out.EmitValue(Value, Size, DEFAULT_ADDRSPACE);
1057
1058      if (Lexer.is(AsmToken::EndOfStatement))
1059        break;
1060
1061      // FIXME: Improve diagnostic.
1062      if (Lexer.isNot(AsmToken::Comma))
1063        return TokError("unexpected token in directive");
1064      Lex();
1065    }
1066  }
1067
1068  Lex();
1069  return false;
1070}
1071
1072/// ParseDirectiveSpace
1073///  ::= .space expression [ , expression ]
1074bool AsmParser::ParseDirectiveSpace() {
1075  int64_t NumBytes;
1076  if (ParseAbsoluteExpression(NumBytes))
1077    return true;
1078
1079  int64_t FillExpr = 0;
1080  bool HasFillExpr = false;
1081  if (Lexer.isNot(AsmToken::EndOfStatement)) {
1082    if (Lexer.isNot(AsmToken::Comma))
1083      return TokError("unexpected token in '.space' directive");
1084    Lex();
1085
1086    if (ParseAbsoluteExpression(FillExpr))
1087      return true;
1088
1089    HasFillExpr = true;
1090
1091    if (Lexer.isNot(AsmToken::EndOfStatement))
1092      return TokError("unexpected token in '.space' directive");
1093  }
1094
1095  Lex();
1096
1097  if (NumBytes <= 0)
1098    return TokError("invalid number of bytes in '.space' directive");
1099
1100  // FIXME: Sometimes the fill expr is 'nop' if it isn't supplied, instead of 0.
1101  Out.EmitFill(NumBytes, FillExpr, DEFAULT_ADDRSPACE);
1102
1103  return false;
1104}
1105
1106/// ParseDirectiveFill
1107///  ::= .fill expression , expression , expression
1108bool AsmParser::ParseDirectiveFill() {
1109  int64_t NumValues;
1110  if (ParseAbsoluteExpression(NumValues))
1111    return true;
1112
1113  if (Lexer.isNot(AsmToken::Comma))
1114    return TokError("unexpected token in '.fill' directive");
1115  Lex();
1116
1117  int64_t FillSize;
1118  if (ParseAbsoluteExpression(FillSize))
1119    return true;
1120
1121  if (Lexer.isNot(AsmToken::Comma))
1122    return TokError("unexpected token in '.fill' directive");
1123  Lex();
1124
1125  int64_t FillExpr;
1126  if (ParseAbsoluteExpression(FillExpr))
1127    return true;
1128
1129  if (Lexer.isNot(AsmToken::EndOfStatement))
1130    return TokError("unexpected token in '.fill' directive");
1131
1132  Lex();
1133
1134  if (FillSize != 1 && FillSize != 2 && FillSize != 4 && FillSize != 8)
1135    return TokError("invalid '.fill' size, expected 1, 2, 4, or 8");
1136
1137  for (uint64_t i = 0, e = NumValues; i != e; ++i)
1138    Out.EmitValue(MCConstantExpr::Create(FillExpr, getContext()), FillSize,
1139                  DEFAULT_ADDRSPACE);
1140
1141  return false;
1142}
1143
1144/// ParseDirectiveOrg
1145///  ::= .org expression [ , expression ]
1146bool AsmParser::ParseDirectiveOrg() {
1147  const MCExpr *Offset;
1148  SMLoc StartLoc = Lexer.getLoc();
1149  if (ParseExpression(Offset))
1150    return true;
1151
1152  // Parse optional fill expression.
1153  int64_t FillExpr = 0;
1154  if (Lexer.isNot(AsmToken::EndOfStatement)) {
1155    if (Lexer.isNot(AsmToken::Comma))
1156      return TokError("unexpected token in '.org' directive");
1157    Lex();
1158
1159    if (ParseAbsoluteExpression(FillExpr))
1160      return true;
1161
1162    if (Lexer.isNot(AsmToken::EndOfStatement))
1163      return TokError("unexpected token in '.org' directive");
1164  }
1165
1166  Lex();
1167
1168  // FIXME: Only limited forms of relocatable expressions are accepted here, it
1169  // has to be relative to the current section.
1170  Out.EmitValueToOffset(Offset, FillExpr);
1171
1172  return false;
1173}
1174
1175/// ParseDirectiveAlign
1176///  ::= {.align, ...} expression [ , expression [ , expression ]]
1177bool AsmParser::ParseDirectiveAlign(bool IsPow2, unsigned ValueSize) {
1178  SMLoc AlignmentLoc = Lexer.getLoc();
1179  int64_t Alignment;
1180  if (ParseAbsoluteExpression(Alignment))
1181    return true;
1182
1183  SMLoc MaxBytesLoc;
1184  bool HasFillExpr = false;
1185  int64_t FillExpr = 0;
1186  int64_t MaxBytesToFill = 0;
1187  if (Lexer.isNot(AsmToken::EndOfStatement)) {
1188    if (Lexer.isNot(AsmToken::Comma))
1189      return TokError("unexpected token in directive");
1190    Lex();
1191
1192    // The fill expression can be omitted while specifying a maximum number of
1193    // alignment bytes, e.g:
1194    //  .align 3,,4
1195    if (Lexer.isNot(AsmToken::Comma)) {
1196      HasFillExpr = true;
1197      if (ParseAbsoluteExpression(FillExpr))
1198        return true;
1199    }
1200
1201    if (Lexer.isNot(AsmToken::EndOfStatement)) {
1202      if (Lexer.isNot(AsmToken::Comma))
1203        return TokError("unexpected token in directive");
1204      Lex();
1205
1206      MaxBytesLoc = Lexer.getLoc();
1207      if (ParseAbsoluteExpression(MaxBytesToFill))
1208        return true;
1209
1210      if (Lexer.isNot(AsmToken::EndOfStatement))
1211        return TokError("unexpected token in directive");
1212    }
1213  }
1214
1215  Lex();
1216
1217  if (!HasFillExpr) {
1218    // FIXME: Sometimes fill with nop.
1219    FillExpr = 0;
1220  }
1221
1222  // Compute alignment in bytes.
1223  if (IsPow2) {
1224    // FIXME: Diagnose overflow.
1225    if (Alignment >= 32) {
1226      Error(AlignmentLoc, "invalid alignment value");
1227      Alignment = 31;
1228    }
1229
1230    Alignment = 1ULL << Alignment;
1231  }
1232
1233  // Diagnose non-sensical max bytes to align.
1234  if (MaxBytesLoc.isValid()) {
1235    if (MaxBytesToFill < 1) {
1236      Error(MaxBytesLoc, "alignment directive can never be satisfied in this "
1237            "many bytes, ignoring maximum bytes expression");
1238      MaxBytesToFill = 0;
1239    }
1240
1241    if (MaxBytesToFill >= Alignment) {
1242      Warning(MaxBytesLoc, "maximum bytes expression exceeds alignment and "
1243              "has no effect");
1244      MaxBytesToFill = 0;
1245    }
1246  }
1247
1248  // FIXME: hard code the parser to use EmitCodeAlignment for text when using
1249  // the TextAlignFillValue.
1250  if(Out.getCurrentSection()->getKind().isText() &&
1251     Lexer.getMAI().getTextAlignFillValue() == FillExpr)
1252    Out.EmitCodeAlignment(Alignment, MaxBytesToFill);
1253  else
1254    // FIXME: Target specific behavior about how the "extra" bytes are filled.
1255    Out.EmitValueToAlignment(Alignment, FillExpr, ValueSize, MaxBytesToFill);
1256
1257  return false;
1258}
1259
1260/// ParseDirectiveSymbolAttribute
1261///  ::= { ".globl", ".weak", ... } [ identifier ( , identifier )* ]
1262bool AsmParser::ParseDirectiveSymbolAttribute(MCSymbolAttr Attr) {
1263  if (Lexer.isNot(AsmToken::EndOfStatement)) {
1264    for (;;) {
1265      StringRef Name;
1266
1267      if (ParseIdentifier(Name))
1268        return TokError("expected identifier in directive");
1269
1270      MCSymbol *Sym = CreateSymbol(Name);
1271
1272      Out.EmitSymbolAttribute(Sym, Attr);
1273
1274      if (Lexer.is(AsmToken::EndOfStatement))
1275        break;
1276
1277      if (Lexer.isNot(AsmToken::Comma))
1278        return TokError("unexpected token in directive");
1279      Lex();
1280    }
1281  }
1282
1283  Lex();
1284  return false;
1285}
1286
1287/// ParseDirectiveDarwinSymbolDesc
1288///  ::= .desc identifier , expression
1289bool AsmParser::ParseDirectiveDarwinSymbolDesc() {
1290  StringRef Name;
1291  if (ParseIdentifier(Name))
1292    return TokError("expected identifier in directive");
1293
1294  // Handle the identifier as the key symbol.
1295  MCSymbol *Sym = CreateSymbol(Name);
1296
1297  if (Lexer.isNot(AsmToken::Comma))
1298    return TokError("unexpected token in '.desc' directive");
1299  Lex();
1300
1301  SMLoc DescLoc = Lexer.getLoc();
1302  int64_t DescValue;
1303  if (ParseAbsoluteExpression(DescValue))
1304    return true;
1305
1306  if (Lexer.isNot(AsmToken::EndOfStatement))
1307    return TokError("unexpected token in '.desc' directive");
1308
1309  Lex();
1310
1311  // Set the n_desc field of this Symbol to this DescValue
1312  Out.EmitSymbolDesc(Sym, DescValue);
1313
1314  return false;
1315}
1316
1317/// ParseDirectiveComm
1318///  ::= ( .comm | .lcomm ) identifier , size_expression [ , align_expression ]
1319bool AsmParser::ParseDirectiveComm(bool IsLocal) {
1320  SMLoc IDLoc = Lexer.getLoc();
1321  StringRef Name;
1322  if (ParseIdentifier(Name))
1323    return TokError("expected identifier in directive");
1324
1325  // Handle the identifier as the key symbol.
1326  MCSymbol *Sym = CreateSymbol(Name);
1327
1328  if (Lexer.isNot(AsmToken::Comma))
1329    return TokError("unexpected token in directive");
1330  Lex();
1331
1332  int64_t Size;
1333  SMLoc SizeLoc = Lexer.getLoc();
1334  if (ParseAbsoluteExpression(Size))
1335    return true;
1336
1337  int64_t Pow2Alignment = 0;
1338  SMLoc Pow2AlignmentLoc;
1339  if (Lexer.is(AsmToken::Comma)) {
1340    Lex();
1341    Pow2AlignmentLoc = Lexer.getLoc();
1342    if (ParseAbsoluteExpression(Pow2Alignment))
1343      return true;
1344
1345    // If this target takes alignments in bytes (not log) validate and convert.
1346    if (Lexer.getMAI().getAlignmentIsInBytes()) {
1347      if (!isPowerOf2_64(Pow2Alignment))
1348        return Error(Pow2AlignmentLoc, "alignment must be a power of 2");
1349      Pow2Alignment = Log2_64(Pow2Alignment);
1350    }
1351  }
1352
1353  if (Lexer.isNot(AsmToken::EndOfStatement))
1354    return TokError("unexpected token in '.comm' or '.lcomm' directive");
1355
1356  Lex();
1357
1358  // NOTE: a size of zero for a .comm should create a undefined symbol
1359  // but a size of .lcomm creates a bss symbol of size zero.
1360  if (Size < 0)
1361    return Error(SizeLoc, "invalid '.comm' or '.lcomm' directive size, can't "
1362                 "be less than zero");
1363
1364  // NOTE: The alignment in the directive is a power of 2 value, the assember
1365  // may internally end up wanting an alignment in bytes.
1366  // FIXME: Diagnose overflow.
1367  if (Pow2Alignment < 0)
1368    return Error(Pow2AlignmentLoc, "invalid '.comm' or '.lcomm' directive "
1369                 "alignment, can't be less than zero");
1370
1371  if (!Sym->isUndefined())
1372    return Error(IDLoc, "invalid symbol redefinition");
1373
1374  // '.lcomm' is equivalent to '.zerofill'.
1375  // Create the Symbol as a common or local common with Size and Pow2Alignment
1376  if (IsLocal) {
1377    Out.EmitZerofill(getMachOSection("__DATA", "__bss",
1378                                     MCSectionMachO::S_ZEROFILL, 0,
1379                                     SectionKind::getBSS()),
1380                     Sym, Size, 1 << Pow2Alignment);
1381    return false;
1382  }
1383
1384  Out.EmitCommonSymbol(Sym, Size, 1 << Pow2Alignment);
1385  return false;
1386}
1387
1388/// ParseDirectiveDarwinZerofill
1389///  ::= .zerofill segname , sectname [, identifier , size_expression [
1390///      , align_expression ]]
1391bool AsmParser::ParseDirectiveDarwinZerofill() {
1392  // FIXME: Handle quoted names here.
1393
1394  if (Lexer.isNot(AsmToken::Identifier))
1395    return TokError("expected segment name after '.zerofill' directive");
1396  StringRef Segment = getTok().getString();
1397  Lex();
1398
1399  if (Lexer.isNot(AsmToken::Comma))
1400    return TokError("unexpected token in directive");
1401  Lex();
1402
1403  if (Lexer.isNot(AsmToken::Identifier))
1404    return TokError("expected section name after comma in '.zerofill' "
1405                    "directive");
1406  StringRef Section = getTok().getString();
1407  Lex();
1408
1409  // If this is the end of the line all that was wanted was to create the
1410  // the section but with no symbol.
1411  if (Lexer.is(AsmToken::EndOfStatement)) {
1412    // Create the zerofill section but no symbol
1413    Out.EmitZerofill(getMachOSection(Segment, Section,
1414                                     MCSectionMachO::S_ZEROFILL, 0,
1415                                     SectionKind::getBSS()));
1416    return false;
1417  }
1418
1419  if (Lexer.isNot(AsmToken::Comma))
1420    return TokError("unexpected token in directive");
1421  Lex();
1422
1423  if (Lexer.isNot(AsmToken::Identifier))
1424    return TokError("expected identifier in directive");
1425
1426  // handle the identifier as the key symbol.
1427  SMLoc IDLoc = Lexer.getLoc();
1428  MCSymbol *Sym = CreateSymbol(getTok().getString());
1429  Lex();
1430
1431  if (Lexer.isNot(AsmToken::Comma))
1432    return TokError("unexpected token in directive");
1433  Lex();
1434
1435  int64_t Size;
1436  SMLoc SizeLoc = Lexer.getLoc();
1437  if (ParseAbsoluteExpression(Size))
1438    return true;
1439
1440  int64_t Pow2Alignment = 0;
1441  SMLoc Pow2AlignmentLoc;
1442  if (Lexer.is(AsmToken::Comma)) {
1443    Lex();
1444    Pow2AlignmentLoc = Lexer.getLoc();
1445    if (ParseAbsoluteExpression(Pow2Alignment))
1446      return true;
1447  }
1448
1449  if (Lexer.isNot(AsmToken::EndOfStatement))
1450    return TokError("unexpected token in '.zerofill' directive");
1451
1452  Lex();
1453
1454  if (Size < 0)
1455    return Error(SizeLoc, "invalid '.zerofill' directive size, can't be less "
1456                 "than zero");
1457
1458  // NOTE: The alignment in the directive is a power of 2 value, the assember
1459  // may internally end up wanting an alignment in bytes.
1460  // FIXME: Diagnose overflow.
1461  if (Pow2Alignment < 0)
1462    return Error(Pow2AlignmentLoc, "invalid '.zerofill' directive alignment, "
1463                 "can't be less than zero");
1464
1465  if (!Sym->isUndefined())
1466    return Error(IDLoc, "invalid symbol redefinition");
1467
1468  // Create the zerofill Symbol with Size and Pow2Alignment
1469  //
1470  // FIXME: Arch specific.
1471  Out.EmitZerofill(getMachOSection(Segment, Section,
1472                                 MCSectionMachO::S_ZEROFILL, 0,
1473                                 SectionKind::getBSS()),
1474                   Sym, Size, 1 << Pow2Alignment);
1475
1476  return false;
1477}
1478
1479/// ParseDirectiveDarwinSubsectionsViaSymbols
1480///  ::= .subsections_via_symbols
1481bool AsmParser::ParseDirectiveDarwinSubsectionsViaSymbols() {
1482  if (Lexer.isNot(AsmToken::EndOfStatement))
1483    return TokError("unexpected token in '.subsections_via_symbols' directive");
1484
1485  Lex();
1486
1487  Out.EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
1488
1489  return false;
1490}
1491
1492/// ParseDirectiveAbort
1493///  ::= .abort [ "abort_string" ]
1494bool AsmParser::ParseDirectiveAbort() {
1495  // FIXME: Use loc from directive.
1496  SMLoc Loc = Lexer.getLoc();
1497
1498  StringRef Str = "";
1499  if (Lexer.isNot(AsmToken::EndOfStatement)) {
1500    if (Lexer.isNot(AsmToken::String))
1501      return TokError("expected string in '.abort' directive");
1502
1503    Str = getTok().getString();
1504
1505    Lex();
1506  }
1507
1508  if (Lexer.isNot(AsmToken::EndOfStatement))
1509    return TokError("unexpected token in '.abort' directive");
1510
1511  Lex();
1512
1513  // FIXME: Handle here.
1514  if (Str.empty())
1515    Error(Loc, ".abort detected. Assembly stopping.");
1516  else
1517    Error(Loc, ".abort '" + Str + "' detected. Assembly stopping.");
1518
1519  return false;
1520}
1521
1522/// ParseDirectiveLsym
1523///  ::= .lsym identifier , expression
1524bool AsmParser::ParseDirectiveDarwinLsym() {
1525  StringRef Name;
1526  if (ParseIdentifier(Name))
1527    return TokError("expected identifier in directive");
1528
1529  // Handle the identifier as the key symbol.
1530  MCSymbol *Sym = CreateSymbol(Name);
1531
1532  if (Lexer.isNot(AsmToken::Comma))
1533    return TokError("unexpected token in '.lsym' directive");
1534  Lex();
1535
1536  const MCExpr *Value;
1537  SMLoc StartLoc = Lexer.getLoc();
1538  if (ParseExpression(Value))
1539    return true;
1540
1541  if (Lexer.isNot(AsmToken::EndOfStatement))
1542    return TokError("unexpected token in '.lsym' directive");
1543
1544  Lex();
1545
1546  // We don't currently support this directive.
1547  //
1548  // FIXME: Diagnostic location!
1549  (void) Sym;
1550  return TokError("directive '.lsym' is unsupported");
1551}
1552
1553/// ParseDirectiveInclude
1554///  ::= .include "filename"
1555bool AsmParser::ParseDirectiveInclude() {
1556  if (Lexer.isNot(AsmToken::String))
1557    return TokError("expected string in '.include' directive");
1558
1559  std::string Filename = getTok().getString();
1560  SMLoc IncludeLoc = Lexer.getLoc();
1561  Lex();
1562
1563  if (Lexer.isNot(AsmToken::EndOfStatement))
1564    return TokError("unexpected token in '.include' directive");
1565
1566  // Strip the quotes.
1567  Filename = Filename.substr(1, Filename.size()-2);
1568
1569  // Attempt to switch the lexer to the included file before consuming the end
1570  // of statement to avoid losing it when we switch.
1571  if (EnterIncludeFile(Filename)) {
1572    PrintMessage(IncludeLoc,
1573                 "Could not find include file '" + Filename + "'",
1574                 "error");
1575    return true;
1576  }
1577
1578  return false;
1579}
1580
1581/// ParseDirectiveDarwinDumpOrLoad
1582///  ::= ( .dump | .load ) "filename"
1583bool AsmParser::ParseDirectiveDarwinDumpOrLoad(SMLoc IDLoc, bool IsDump) {
1584  if (Lexer.isNot(AsmToken::String))
1585    return TokError("expected string in '.dump' or '.load' directive");
1586
1587  Lex();
1588
1589  if (Lexer.isNot(AsmToken::EndOfStatement))
1590    return TokError("unexpected token in '.dump' or '.load' directive");
1591
1592  Lex();
1593
1594  // FIXME: If/when .dump and .load are implemented they will be done in the
1595  // the assembly parser and not have any need for an MCStreamer API.
1596  if (IsDump)
1597    Warning(IDLoc, "ignoring directive .dump for now");
1598  else
1599    Warning(IDLoc, "ignoring directive .load for now");
1600
1601  return false;
1602}
1603
1604/// ParseDirectiveIf
1605/// ::= .if expression
1606bool AsmParser::ParseDirectiveIf(SMLoc DirectiveLoc) {
1607  // Consume the identifier that was the .if directive
1608  Lex();
1609
1610  TheCondStack.push_back(TheCondState);
1611  TheCondState.TheCond = AsmCond::IfCond;
1612  if(TheCondState.Ignore) {
1613    EatToEndOfStatement();
1614  }
1615  else {
1616    int64_t ExprValue;
1617    if (ParseAbsoluteExpression(ExprValue))
1618      return true;
1619
1620    if (Lexer.isNot(AsmToken::EndOfStatement))
1621      return TokError("unexpected token in '.if' directive");
1622
1623    Lex();
1624
1625    TheCondState.CondMet = ExprValue;
1626    TheCondState.Ignore = !TheCondState.CondMet;
1627  }
1628
1629  return false;
1630}
1631
1632/// ParseDirectiveElseIf
1633/// ::= .elseif expression
1634bool AsmParser::ParseDirectiveElseIf(SMLoc DirectiveLoc) {
1635  if (TheCondState.TheCond != AsmCond::IfCond &&
1636      TheCondState.TheCond != AsmCond::ElseIfCond)
1637      Error(DirectiveLoc, "Encountered a .elseif that doesn't follow a .if or "
1638                          " an .elseif");
1639  TheCondState.TheCond = AsmCond::ElseIfCond;
1640
1641  // Consume the identifier that was the .elseif directive
1642  Lex();
1643
1644  bool LastIgnoreState = false;
1645  if (!TheCondStack.empty())
1646      LastIgnoreState = TheCondStack.back().Ignore;
1647  if (LastIgnoreState || TheCondState.CondMet) {
1648    TheCondState.Ignore = true;
1649    EatToEndOfStatement();
1650  }
1651  else {
1652    int64_t ExprValue;
1653    if (ParseAbsoluteExpression(ExprValue))
1654      return true;
1655
1656    if (Lexer.isNot(AsmToken::EndOfStatement))
1657      return TokError("unexpected token in '.elseif' directive");
1658
1659    Lex();
1660    TheCondState.CondMet = ExprValue;
1661    TheCondState.Ignore = !TheCondState.CondMet;
1662  }
1663
1664  return false;
1665}
1666
1667/// ParseDirectiveElse
1668/// ::= .else
1669bool AsmParser::ParseDirectiveElse(SMLoc DirectiveLoc) {
1670  // Consume the identifier that was the .else directive
1671  Lex();
1672
1673  if (Lexer.isNot(AsmToken::EndOfStatement))
1674    return TokError("unexpected token in '.else' directive");
1675
1676  Lex();
1677
1678  if (TheCondState.TheCond != AsmCond::IfCond &&
1679      TheCondState.TheCond != AsmCond::ElseIfCond)
1680      Error(DirectiveLoc, "Encountered a .else that doesn't follow a .if or an "
1681                          ".elseif");
1682  TheCondState.TheCond = AsmCond::ElseCond;
1683  bool LastIgnoreState = false;
1684  if (!TheCondStack.empty())
1685    LastIgnoreState = TheCondStack.back().Ignore;
1686  if (LastIgnoreState || TheCondState.CondMet)
1687    TheCondState.Ignore = true;
1688  else
1689    TheCondState.Ignore = false;
1690
1691  return false;
1692}
1693
1694/// ParseDirectiveEndIf
1695/// ::= .endif
1696bool AsmParser::ParseDirectiveEndIf(SMLoc DirectiveLoc) {
1697  // Consume the identifier that was the .endif directive
1698  Lex();
1699
1700  if (Lexer.isNot(AsmToken::EndOfStatement))
1701    return TokError("unexpected token in '.endif' directive");
1702
1703  Lex();
1704
1705  if ((TheCondState.TheCond == AsmCond::NoCond) ||
1706      TheCondStack.empty())
1707    Error(DirectiveLoc, "Encountered a .endif that doesn't follow a .if or "
1708                        ".else");
1709  if (!TheCondStack.empty()) {
1710    TheCondState = TheCondStack.back();
1711    TheCondStack.pop_back();
1712  }
1713
1714  return false;
1715}
1716
1717/// ParseDirectiveFile
1718/// ::= .file [number] string
1719bool AsmParser::ParseDirectiveFile(StringRef, SMLoc DirectiveLoc) {
1720  // FIXME: I'm not sure what this is.
1721  int64_t FileNumber = -1;
1722  if (Lexer.is(AsmToken::Integer)) {
1723    FileNumber = getTok().getIntVal();
1724    Lex();
1725
1726    if (FileNumber < 1)
1727      return TokError("file number less than one");
1728  }
1729
1730  if (Lexer.isNot(AsmToken::String))
1731    return TokError("unexpected token in '.file' directive");
1732
1733  StringRef Filename = getTok().getString();
1734  Filename = Filename.substr(1, Filename.size()-2);
1735  Lex();
1736
1737  if (Lexer.isNot(AsmToken::EndOfStatement))
1738    return TokError("unexpected token in '.file' directive");
1739
1740  if (FileNumber == -1)
1741    Out.EmitFileDirective(Filename);
1742  else
1743    Out.EmitDwarfFileDirective(FileNumber, Filename);
1744
1745  return false;
1746}
1747
1748/// ParseDirectiveLine
1749/// ::= .line [number]
1750bool AsmParser::ParseDirectiveLine(StringRef, SMLoc DirectiveLoc) {
1751  if (Lexer.isNot(AsmToken::EndOfStatement)) {
1752    if (Lexer.isNot(AsmToken::Integer))
1753      return TokError("unexpected token in '.line' directive");
1754
1755    int64_t LineNumber = getTok().getIntVal();
1756    (void) LineNumber;
1757    Lex();
1758
1759    // FIXME: Do something with the .line.
1760  }
1761
1762  if (Lexer.isNot(AsmToken::EndOfStatement))
1763    return TokError("unexpected token in '.file' directive");
1764
1765  return false;
1766}
1767
1768
1769/// ParseDirectiveLoc
1770/// ::= .loc number [number [number]]
1771bool AsmParser::ParseDirectiveLoc(StringRef, SMLoc DirectiveLoc) {
1772  if (Lexer.isNot(AsmToken::Integer))
1773    return TokError("unexpected token in '.loc' directive");
1774
1775  // FIXME: What are these fields?
1776  int64_t FileNumber = getTok().getIntVal();
1777  (void) FileNumber;
1778  // FIXME: Validate file.
1779
1780  Lex();
1781  if (Lexer.isNot(AsmToken::EndOfStatement)) {
1782    if (Lexer.isNot(AsmToken::Integer))
1783      return TokError("unexpected token in '.loc' directive");
1784
1785    int64_t Param2 = getTok().getIntVal();
1786    (void) Param2;
1787    Lex();
1788
1789    if (Lexer.isNot(AsmToken::EndOfStatement)) {
1790      if (Lexer.isNot(AsmToken::Integer))
1791        return TokError("unexpected token in '.loc' directive");
1792
1793      int64_t Param3 = getTok().getIntVal();
1794      (void) Param3;
1795      Lex();
1796
1797      // FIXME: Do something with the .loc.
1798    }
1799  }
1800
1801  if (Lexer.isNot(AsmToken::EndOfStatement))
1802    return TokError("unexpected token in '.file' directive");
1803
1804  return false;
1805}
1806
1807