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      1 //===- DarwinAsmParser.cpp - Darwin (Mach-O) Assembly Parser --------------===//
      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 #include "llvm/MC/MCParser/MCAsmParserExtension.h"
     11 #include "llvm/MC/MCContext.h"
     12 #include "llvm/MC/MCSectionMachO.h"
     13 #include "llvm/MC/MCStreamer.h"
     14 #include "llvm/MC/MCSymbol.h"
     15 #include "llvm/MC/MCParser/MCAsmLexer.h"
     16 #include "llvm/MC/MCParser/MCAsmParser.h"
     17 #include "llvm/ADT/StringRef.h"
     18 #include "llvm/ADT/Twine.h"
     19 #include "llvm/Support/MemoryBuffer.h"
     20 #include "llvm/Support/SourceMgr.h"
     21 using namespace llvm;
     22 
     23 namespace {
     24 
     25 /// \brief Implementation of directive handling which is shared across all
     26 /// Darwin targets.
     27 class DarwinAsmParser : public MCAsmParserExtension {
     28   template<bool (DarwinAsmParser::*Handler)(StringRef, SMLoc)>
     29   void AddDirectiveHandler(StringRef Directive) {
     30     getParser().AddDirectiveHandler(this, Directive,
     31                                     HandleDirective<DarwinAsmParser, Handler>);
     32   }
     33 
     34   bool ParseSectionSwitch(const char *Segment, const char *Section,
     35                           unsigned TAA = 0, unsigned ImplicitAlign = 0,
     36                           unsigned StubSize = 0);
     37 
     38 public:
     39   DarwinAsmParser() {}
     40 
     41   virtual void Initialize(MCAsmParser &Parser) {
     42     // Call the base implementation.
     43     this->MCAsmParserExtension::Initialize(Parser);
     44 
     45     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveDesc>(".desc");
     46     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveLsym>(".lsym");
     47     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveSubsectionsViaSymbols>(
     48       ".subsections_via_symbols");
     49     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveDumpOrLoad>(".dump");
     50     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveDumpOrLoad>(".load");
     51     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveSection>(".section");
     52     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveSecureLogUnique>(
     53       ".secure_log_unique");
     54     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveSecureLogReset>(
     55       ".secure_log_reset");
     56     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveTBSS>(".tbss");
     57     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveZerofill>(".zerofill");
     58 
     59     // Special section directives.
     60     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveConst>(".const");
     61     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveConstData>(".const_data");
     62     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveConstructor>(".constructor");
     63     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveCString>(".cstring");
     64     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveData>(".data");
     65     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveDestructor>(".destructor");
     66     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveDyld>(".dyld");
     67     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveFVMLibInit0>(".fvmlib_init0");
     68     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveFVMLibInit1>(".fvmlib_init1");
     69     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveLazySymbolPointers>(".lazy_symbol_pointer");
     70     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveLiteral16>(".literal16");
     71     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveLiteral4>(".literal4");
     72     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveLiteral8>(".literal8");
     73     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveModInitFunc>(".mod_init_func");
     74     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveModTermFunc>(".mod_term_func");
     75     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveNonLazySymbolPointers>(".non_lazy_symbol_pointer");
     76     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCCatClsMeth>(".objc_cat_cls_meth");
     77     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCCatInstMeth>(".objc_cat_inst_meth");
     78     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCCategory>(".objc_category");
     79     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCClass>(".objc_class");
     80     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCClassNames>(".objc_class_names");
     81     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCClassVars>(".objc_class_vars");
     82     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCClsMeth>(".objc_cls_meth");
     83     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCClsRefs>(".objc_cls_refs");
     84     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCInstMeth>(".objc_inst_meth");
     85     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCInstanceVars>(".objc_instance_vars");
     86     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCMessageRefs>(".objc_message_refs");
     87     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCMetaClass>(".objc_meta_class");
     88     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCMethVarNames>(".objc_meth_var_names");
     89     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCMethVarTypes>(".objc_meth_var_types");
     90     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCModuleInfo>(".objc_module_info");
     91     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCProtocol>(".objc_protocol");
     92     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCSelectorStrs>(".objc_selector_strs");
     93     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCStringObject>(".objc_string_object");
     94     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveObjCSymbols>(".objc_symbols");
     95     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectivePICSymbolStub>(".picsymbol_stub");
     96     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveStaticConst>(".static_const");
     97     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveStaticData>(".static_data");
     98     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveSymbolStub>(".symbol_stub");
     99     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveTData>(".tdata");
    100     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveText>(".text");
    101     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveThreadInitFunc>(".thread_init_func");
    102     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveTLV>(".tlv");
    103 
    104     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveIdent>(".ident");
    105   }
    106 
    107   bool ParseDirectiveDesc(StringRef, SMLoc);
    108   bool ParseDirectiveDumpOrLoad(StringRef, SMLoc);
    109   bool ParseDirectiveLsym(StringRef, SMLoc);
    110   bool ParseDirectiveSection(StringRef, SMLoc);
    111   bool ParseDirectiveSecureLogReset(StringRef, SMLoc);
    112   bool ParseDirectiveSecureLogUnique(StringRef, SMLoc);
    113   bool ParseDirectiveSubsectionsViaSymbols(StringRef, SMLoc);
    114   bool ParseDirectiveTBSS(StringRef, SMLoc);
    115   bool ParseDirectiveZerofill(StringRef, SMLoc);
    116 
    117   // Named Section Directive
    118   bool ParseSectionDirectiveConst(StringRef, SMLoc) {
    119     return ParseSectionSwitch("__TEXT", "__const");
    120   }
    121   bool ParseSectionDirectiveStaticConst(StringRef, SMLoc) {
    122     return ParseSectionSwitch("__TEXT", "__static_const");
    123   }
    124   bool ParseSectionDirectiveCString(StringRef, SMLoc) {
    125     return ParseSectionSwitch("__TEXT","__cstring",
    126                               MCSectionMachO::S_CSTRING_LITERALS);
    127   }
    128   bool ParseSectionDirectiveLiteral4(StringRef, SMLoc) {
    129     return ParseSectionSwitch("__TEXT", "__literal4",
    130                               MCSectionMachO::S_4BYTE_LITERALS, 4);
    131   }
    132   bool ParseSectionDirectiveLiteral8(StringRef, SMLoc) {
    133     return ParseSectionSwitch("__TEXT", "__literal8",
    134                               MCSectionMachO::S_8BYTE_LITERALS, 8);
    135   }
    136   bool ParseSectionDirectiveLiteral16(StringRef, SMLoc) {
    137     return ParseSectionSwitch("__TEXT","__literal16",
    138                               MCSectionMachO::S_16BYTE_LITERALS, 16);
    139   }
    140   bool ParseSectionDirectiveConstructor(StringRef, SMLoc) {
    141     return ParseSectionSwitch("__TEXT","__constructor");
    142   }
    143   bool ParseSectionDirectiveDestructor(StringRef, SMLoc) {
    144     return ParseSectionSwitch("__TEXT","__destructor");
    145   }
    146   bool ParseSectionDirectiveFVMLibInit0(StringRef, SMLoc) {
    147     return ParseSectionSwitch("__TEXT","__fvmlib_init0");
    148   }
    149   bool ParseSectionDirectiveFVMLibInit1(StringRef, SMLoc) {
    150     return ParseSectionSwitch("__TEXT","__fvmlib_init1");
    151   }
    152   bool ParseSectionDirectiveSymbolStub(StringRef, SMLoc) {
    153     return ParseSectionSwitch("__TEXT","__symbol_stub",
    154                               MCSectionMachO::S_SYMBOL_STUBS |
    155                               MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
    156                               // FIXME: Different on PPC and ARM.
    157                               0, 16);
    158   }
    159   bool ParseSectionDirectivePICSymbolStub(StringRef, SMLoc) {
    160     return ParseSectionSwitch("__TEXT","__picsymbol_stub",
    161                               MCSectionMachO::S_SYMBOL_STUBS |
    162                               MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS, 0, 26);
    163   }
    164   bool ParseSectionDirectiveData(StringRef, SMLoc) {
    165     return ParseSectionSwitch("__DATA", "__data");
    166   }
    167   bool ParseSectionDirectiveStaticData(StringRef, SMLoc) {
    168     return ParseSectionSwitch("__DATA", "__static_data");
    169   }
    170   bool ParseSectionDirectiveNonLazySymbolPointers(StringRef, SMLoc) {
    171     return ParseSectionSwitch("__DATA", "__nl_symbol_ptr",
    172                               MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS, 4);
    173   }
    174   bool ParseSectionDirectiveLazySymbolPointers(StringRef, SMLoc) {
    175     return ParseSectionSwitch("__DATA", "__la_symbol_ptr",
    176                               MCSectionMachO::S_LAZY_SYMBOL_POINTERS, 4);
    177   }
    178   bool ParseSectionDirectiveDyld(StringRef, SMLoc) {
    179     return ParseSectionSwitch("__DATA", "__dyld");
    180   }
    181   bool ParseSectionDirectiveModInitFunc(StringRef, SMLoc) {
    182     return ParseSectionSwitch("__DATA", "__mod_init_func",
    183                               MCSectionMachO::S_MOD_INIT_FUNC_POINTERS, 4);
    184   }
    185   bool ParseSectionDirectiveModTermFunc(StringRef, SMLoc) {
    186     return ParseSectionSwitch("__DATA", "__mod_term_func",
    187                               MCSectionMachO::S_MOD_TERM_FUNC_POINTERS, 4);
    188   }
    189   bool ParseSectionDirectiveConstData(StringRef, SMLoc) {
    190     return ParseSectionSwitch("__DATA", "__const");
    191   }
    192   bool ParseSectionDirectiveObjCClass(StringRef, SMLoc) {
    193     return ParseSectionSwitch("__OBJC", "__class",
    194                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    195   }
    196   bool ParseSectionDirectiveObjCMetaClass(StringRef, SMLoc) {
    197     return ParseSectionSwitch("__OBJC", "__meta_class",
    198                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    199   }
    200   bool ParseSectionDirectiveObjCCatClsMeth(StringRef, SMLoc) {
    201     return ParseSectionSwitch("__OBJC", "__cat_cls_meth",
    202                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    203   }
    204   bool ParseSectionDirectiveObjCCatInstMeth(StringRef, SMLoc) {
    205     return ParseSectionSwitch("__OBJC", "__cat_inst_meth",
    206                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    207   }
    208   bool ParseSectionDirectiveObjCProtocol(StringRef, SMLoc) {
    209     return ParseSectionSwitch("__OBJC", "__protocol",
    210                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    211   }
    212   bool ParseSectionDirectiveObjCStringObject(StringRef, SMLoc) {
    213     return ParseSectionSwitch("__OBJC", "__string_object",
    214                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    215   }
    216   bool ParseSectionDirectiveObjCClsMeth(StringRef, SMLoc) {
    217     return ParseSectionSwitch("__OBJC", "__cls_meth",
    218                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    219   }
    220   bool ParseSectionDirectiveObjCInstMeth(StringRef, SMLoc) {
    221     return ParseSectionSwitch("__OBJC", "__inst_meth",
    222                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    223   }
    224   bool ParseSectionDirectiveObjCClsRefs(StringRef, SMLoc) {
    225     return ParseSectionSwitch("__OBJC", "__cls_refs",
    226                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP |
    227                               MCSectionMachO::S_LITERAL_POINTERS, 4);
    228   }
    229   bool ParseSectionDirectiveObjCMessageRefs(StringRef, SMLoc) {
    230     return ParseSectionSwitch("__OBJC", "__message_refs",
    231                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP |
    232                               MCSectionMachO::S_LITERAL_POINTERS, 4);
    233   }
    234   bool ParseSectionDirectiveObjCSymbols(StringRef, SMLoc) {
    235     return ParseSectionSwitch("__OBJC", "__symbols",
    236                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    237   }
    238   bool ParseSectionDirectiveObjCCategory(StringRef, SMLoc) {
    239     return ParseSectionSwitch("__OBJC", "__category",
    240                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    241   }
    242   bool ParseSectionDirectiveObjCClassVars(StringRef, SMLoc) {
    243     return ParseSectionSwitch("__OBJC", "__class_vars",
    244                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    245   }
    246   bool ParseSectionDirectiveObjCInstanceVars(StringRef, SMLoc) {
    247     return ParseSectionSwitch("__OBJC", "__instance_vars",
    248                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    249   }
    250   bool ParseSectionDirectiveObjCModuleInfo(StringRef, SMLoc) {
    251     return ParseSectionSwitch("__OBJC", "__module_info",
    252                               MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
    253   }
    254   bool ParseSectionDirectiveObjCClassNames(StringRef, SMLoc) {
    255     return ParseSectionSwitch("__TEXT", "__cstring",
    256                               MCSectionMachO::S_CSTRING_LITERALS);
    257   }
    258   bool ParseSectionDirectiveObjCMethVarTypes(StringRef, SMLoc) {
    259     return ParseSectionSwitch("__TEXT", "__cstring",
    260                               MCSectionMachO::S_CSTRING_LITERALS);
    261   }
    262   bool ParseSectionDirectiveObjCMethVarNames(StringRef, SMLoc) {
    263     return ParseSectionSwitch("__TEXT", "__cstring",
    264                               MCSectionMachO::S_CSTRING_LITERALS);
    265   }
    266   bool ParseSectionDirectiveObjCSelectorStrs(StringRef, SMLoc) {
    267     return ParseSectionSwitch("__OBJC", "__selector_strs",
    268                               MCSectionMachO::S_CSTRING_LITERALS);
    269   }
    270   bool ParseSectionDirectiveTData(StringRef, SMLoc) {
    271     return ParseSectionSwitch("__DATA", "__thread_data",
    272                               MCSectionMachO::S_THREAD_LOCAL_REGULAR);
    273   }
    274   bool ParseSectionDirectiveText(StringRef, SMLoc) {
    275     return ParseSectionSwitch("__TEXT", "__text",
    276                               MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS);
    277   }
    278   bool ParseSectionDirectiveTLV(StringRef, SMLoc) {
    279     return ParseSectionSwitch("__DATA", "__thread_vars",
    280                               MCSectionMachO::S_THREAD_LOCAL_VARIABLES);
    281   }
    282   bool ParseSectionDirectiveIdent(StringRef, SMLoc) {
    283     // Darwin silently ignores the .ident directive.
    284     getParser().EatToEndOfStatement();
    285     return false;
    286   }
    287   bool ParseSectionDirectiveThreadInitFunc(StringRef, SMLoc) {
    288     return ParseSectionSwitch("__DATA", "__thread_init",
    289                          MCSectionMachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS);
    290   }
    291 
    292 };
    293 
    294 }
    295 
    296 bool DarwinAsmParser::ParseSectionSwitch(const char *Segment,
    297                                          const char *Section,
    298                                          unsigned TAA, unsigned Align,
    299                                          unsigned StubSize) {
    300   if (getLexer().isNot(AsmToken::EndOfStatement))
    301     return TokError("unexpected token in section switching directive");
    302   Lex();
    303 
    304   // FIXME: Arch specific.
    305   bool isText = StringRef(Segment) == "__TEXT";  // FIXME: Hack.
    306   getStreamer().SwitchSection(getContext().getMachOSection(
    307                                 Segment, Section, TAA, StubSize,
    308                                 isText ? SectionKind::getText()
    309                                        : SectionKind::getDataRel()));
    310 
    311   // Set the implicit alignment, if any.
    312   //
    313   // FIXME: This isn't really what 'as' does; I think it just uses the implicit
    314   // alignment on the section (e.g., if one manually inserts bytes into the
    315   // section, then just issuing the section switch directive will not realign
    316   // the section. However, this is arguably more reasonable behavior, and there
    317   // is no good reason for someone to intentionally emit incorrectly sized
    318   // values into the implicitly aligned sections.
    319   if (Align)
    320     getStreamer().EmitValueToAlignment(Align, 0, 1, 0);
    321 
    322   return false;
    323 }
    324 
    325 /// ParseDirectiveDesc
    326 ///  ::= .desc identifier , expression
    327 bool DarwinAsmParser::ParseDirectiveDesc(StringRef, SMLoc) {
    328   StringRef Name;
    329   if (getParser().ParseIdentifier(Name))
    330     return TokError("expected identifier in directive");
    331 
    332   // Handle the identifier as the key symbol.
    333   MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
    334 
    335   if (getLexer().isNot(AsmToken::Comma))
    336     return TokError("unexpected token in '.desc' directive");
    337   Lex();
    338 
    339   int64_t DescValue;
    340   if (getParser().ParseAbsoluteExpression(DescValue))
    341     return true;
    342 
    343   if (getLexer().isNot(AsmToken::EndOfStatement))
    344     return TokError("unexpected token in '.desc' directive");
    345 
    346   Lex();
    347 
    348   // Set the n_desc field of this Symbol to this DescValue
    349   getStreamer().EmitSymbolDesc(Sym, DescValue);
    350 
    351   return false;
    352 }
    353 
    354 /// ParseDirectiveDumpOrLoad
    355 ///  ::= ( .dump | .load ) "filename"
    356 bool DarwinAsmParser::ParseDirectiveDumpOrLoad(StringRef Directive,
    357                                                SMLoc IDLoc) {
    358   bool IsDump = Directive == ".dump";
    359   if (getLexer().isNot(AsmToken::String))
    360     return TokError("expected string in '.dump' or '.load' directive");
    361 
    362   Lex();
    363 
    364   if (getLexer().isNot(AsmToken::EndOfStatement))
    365     return TokError("unexpected token in '.dump' or '.load' directive");
    366 
    367   Lex();
    368 
    369   // FIXME: If/when .dump and .load are implemented they will be done in the
    370   // the assembly parser and not have any need for an MCStreamer API.
    371   if (IsDump)
    372     return Warning(IDLoc, "ignoring directive .dump for now");
    373   else
    374     return Warning(IDLoc, "ignoring directive .load for now");
    375 }
    376 
    377 /// ParseDirectiveLsym
    378 ///  ::= .lsym identifier , expression
    379 bool DarwinAsmParser::ParseDirectiveLsym(StringRef, SMLoc) {
    380   StringRef Name;
    381   if (getParser().ParseIdentifier(Name))
    382     return TokError("expected identifier in directive");
    383 
    384   // Handle the identifier as the key symbol.
    385   MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
    386 
    387   if (getLexer().isNot(AsmToken::Comma))
    388     return TokError("unexpected token in '.lsym' directive");
    389   Lex();
    390 
    391   const MCExpr *Value;
    392   if (getParser().ParseExpression(Value))
    393     return true;
    394 
    395   if (getLexer().isNot(AsmToken::EndOfStatement))
    396     return TokError("unexpected token in '.lsym' directive");
    397 
    398   Lex();
    399 
    400   // We don't currently support this directive.
    401   //
    402   // FIXME: Diagnostic location!
    403   (void) Sym;
    404   return TokError("directive '.lsym' is unsupported");
    405 }
    406 
    407 /// ParseDirectiveSection:
    408 ///   ::= .section identifier (',' identifier)*
    409 bool DarwinAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
    410   SMLoc Loc = getLexer().getLoc();
    411 
    412   StringRef SectionName;
    413   if (getParser().ParseIdentifier(SectionName))
    414     return Error(Loc, "expected identifier after '.section' directive");
    415 
    416   // Verify there is a following comma.
    417   if (!getLexer().is(AsmToken::Comma))
    418     return TokError("unexpected token in '.section' directive");
    419 
    420   std::string SectionSpec = SectionName;
    421   SectionSpec += ",";
    422 
    423   // Add all the tokens until the end of the line, ParseSectionSpecifier will
    424   // handle this.
    425   StringRef EOL = getLexer().LexUntilEndOfStatement();
    426   SectionSpec.append(EOL.begin(), EOL.end());
    427 
    428   Lex();
    429   if (getLexer().isNot(AsmToken::EndOfStatement))
    430     return TokError("unexpected token in '.section' directive");
    431   Lex();
    432 
    433 
    434   StringRef Segment, Section;
    435   unsigned StubSize;
    436   unsigned TAA;
    437   bool TAAParsed;
    438   std::string ErrorStr =
    439     MCSectionMachO::ParseSectionSpecifier(SectionSpec, Segment, Section,
    440                                           TAA, TAAParsed, StubSize);
    441 
    442   if (!ErrorStr.empty())
    443     return Error(Loc, ErrorStr.c_str());
    444 
    445   // FIXME: Arch specific.
    446   bool isText = Segment == "__TEXT";  // FIXME: Hack.
    447   getStreamer().SwitchSection(getContext().getMachOSection(
    448                                 Segment, Section, TAA, StubSize,
    449                                 isText ? SectionKind::getText()
    450                                 : SectionKind::getDataRel()));
    451   return false;
    452 }
    453 
    454 /// ParseDirectiveSecureLogUnique
    455 ///  ::= .secure_log_unique ... message ...
    456 bool DarwinAsmParser::ParseDirectiveSecureLogUnique(StringRef, SMLoc IDLoc) {
    457   StringRef LogMessage = getParser().ParseStringToEndOfStatement();
    458   if (getLexer().isNot(AsmToken::EndOfStatement))
    459     return TokError("unexpected token in '.secure_log_unique' directive");
    460 
    461   if (getContext().getSecureLogUsed() != false)
    462     return Error(IDLoc, ".secure_log_unique specified multiple times");
    463 
    464   // Get the secure log path.
    465   const char *SecureLogFile = getContext().getSecureLogFile();
    466   if (SecureLogFile == NULL)
    467     return Error(IDLoc, ".secure_log_unique used but AS_SECURE_LOG_FILE "
    468                  "environment variable unset.");
    469 
    470   // Open the secure log file if we haven't already.
    471   raw_ostream *OS = getContext().getSecureLog();
    472   if (OS == NULL) {
    473     std::string Err;
    474     OS = new raw_fd_ostream(SecureLogFile, Err, raw_fd_ostream::F_Append);
    475     if (!Err.empty()) {
    476        delete OS;
    477        return Error(IDLoc, Twine("can't open secure log file: ") +
    478                     SecureLogFile + " (" + Err + ")");
    479     }
    480     getContext().setSecureLog(OS);
    481   }
    482 
    483   // Write the message.
    484   int CurBuf = getSourceManager().FindBufferContainingLoc(IDLoc);
    485   *OS << getSourceManager().getBufferInfo(CurBuf).Buffer->getBufferIdentifier()
    486       << ":" << getSourceManager().FindLineNumber(IDLoc, CurBuf) << ":"
    487       << LogMessage + "\n";
    488 
    489   getContext().setSecureLogUsed(true);
    490 
    491   return false;
    492 }
    493 
    494 /// ParseDirectiveSecureLogReset
    495 ///  ::= .secure_log_reset
    496 bool DarwinAsmParser::ParseDirectiveSecureLogReset(StringRef, SMLoc IDLoc) {
    497   if (getLexer().isNot(AsmToken::EndOfStatement))
    498     return TokError("unexpected token in '.secure_log_reset' directive");
    499 
    500   Lex();
    501 
    502   getContext().setSecureLogUsed(false);
    503 
    504   return false;
    505 }
    506 
    507 /// ParseDirectiveSubsectionsViaSymbols
    508 ///  ::= .subsections_via_symbols
    509 bool DarwinAsmParser::ParseDirectiveSubsectionsViaSymbols(StringRef, SMLoc) {
    510   if (getLexer().isNot(AsmToken::EndOfStatement))
    511     return TokError("unexpected token in '.subsections_via_symbols' directive");
    512 
    513   Lex();
    514 
    515   getStreamer().EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
    516 
    517   return false;
    518 }
    519 
    520 /// ParseDirectiveTBSS
    521 ///  ::= .tbss identifier, size, align
    522 bool DarwinAsmParser::ParseDirectiveTBSS(StringRef, SMLoc) {
    523   SMLoc IDLoc = getLexer().getLoc();
    524   StringRef Name;
    525   if (getParser().ParseIdentifier(Name))
    526     return TokError("expected identifier in directive");
    527 
    528   // Handle the identifier as the key symbol.
    529   MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
    530 
    531   if (getLexer().isNot(AsmToken::Comma))
    532     return TokError("unexpected token in directive");
    533   Lex();
    534 
    535   int64_t Size;
    536   SMLoc SizeLoc = getLexer().getLoc();
    537   if (getParser().ParseAbsoluteExpression(Size))
    538     return true;
    539 
    540   int64_t Pow2Alignment = 0;
    541   SMLoc Pow2AlignmentLoc;
    542   if (getLexer().is(AsmToken::Comma)) {
    543     Lex();
    544     Pow2AlignmentLoc = getLexer().getLoc();
    545     if (getParser().ParseAbsoluteExpression(Pow2Alignment))
    546       return true;
    547   }
    548 
    549   if (getLexer().isNot(AsmToken::EndOfStatement))
    550     return TokError("unexpected token in '.tbss' directive");
    551 
    552   Lex();
    553 
    554   if (Size < 0)
    555     return Error(SizeLoc, "invalid '.tbss' directive size, can't be less than"
    556                  "zero");
    557 
    558   // FIXME: Diagnose overflow.
    559   if (Pow2Alignment < 0)
    560     return Error(Pow2AlignmentLoc, "invalid '.tbss' alignment, can't be less"
    561                  "than zero");
    562 
    563   if (!Sym->isUndefined())
    564     return Error(IDLoc, "invalid symbol redefinition");
    565 
    566   getStreamer().EmitTBSSSymbol(getContext().getMachOSection(
    567                                  "__DATA", "__thread_bss",
    568                                  MCSectionMachO::S_THREAD_LOCAL_ZEROFILL,
    569                                  0, SectionKind::getThreadBSS()),
    570                                Sym, Size, 1 << Pow2Alignment);
    571 
    572   return false;
    573 }
    574 
    575 /// ParseDirectiveZerofill
    576 ///  ::= .zerofill segname , sectname [, identifier , size_expression [
    577 ///      , align_expression ]]
    578 bool DarwinAsmParser::ParseDirectiveZerofill(StringRef, SMLoc) {
    579   StringRef Segment;
    580   if (getParser().ParseIdentifier(Segment))
    581     return TokError("expected segment name after '.zerofill' directive");
    582 
    583   if (getLexer().isNot(AsmToken::Comma))
    584     return TokError("unexpected token in directive");
    585   Lex();
    586 
    587   StringRef Section;
    588   if (getParser().ParseIdentifier(Section))
    589     return TokError("expected section name after comma in '.zerofill' "
    590                     "directive");
    591 
    592   // If this is the end of the line all that was wanted was to create the
    593   // the section but with no symbol.
    594   if (getLexer().is(AsmToken::EndOfStatement)) {
    595     // Create the zerofill section but no symbol
    596     getStreamer().EmitZerofill(getContext().getMachOSection(
    597                                  Segment, Section, MCSectionMachO::S_ZEROFILL,
    598                                  0, SectionKind::getBSS()));
    599     return false;
    600   }
    601 
    602   if (getLexer().isNot(AsmToken::Comma))
    603     return TokError("unexpected token in directive");
    604   Lex();
    605 
    606   SMLoc IDLoc = getLexer().getLoc();
    607   StringRef IDStr;
    608   if (getParser().ParseIdentifier(IDStr))
    609     return TokError("expected identifier in directive");
    610 
    611   // handle the identifier as the key symbol.
    612   MCSymbol *Sym = getContext().GetOrCreateSymbol(IDStr);
    613 
    614   if (getLexer().isNot(AsmToken::Comma))
    615     return TokError("unexpected token in directive");
    616   Lex();
    617 
    618   int64_t Size;
    619   SMLoc SizeLoc = getLexer().getLoc();
    620   if (getParser().ParseAbsoluteExpression(Size))
    621     return true;
    622 
    623   int64_t Pow2Alignment = 0;
    624   SMLoc Pow2AlignmentLoc;
    625   if (getLexer().is(AsmToken::Comma)) {
    626     Lex();
    627     Pow2AlignmentLoc = getLexer().getLoc();
    628     if (getParser().ParseAbsoluteExpression(Pow2Alignment))
    629       return true;
    630   }
    631 
    632   if (getLexer().isNot(AsmToken::EndOfStatement))
    633     return TokError("unexpected token in '.zerofill' directive");
    634 
    635   Lex();
    636 
    637   if (Size < 0)
    638     return Error(SizeLoc, "invalid '.zerofill' directive size, can't be less "
    639                  "than zero");
    640 
    641   // NOTE: The alignment in the directive is a power of 2 value, the assembler
    642   // may internally end up wanting an alignment in bytes.
    643   // FIXME: Diagnose overflow.
    644   if (Pow2Alignment < 0)
    645     return Error(Pow2AlignmentLoc, "invalid '.zerofill' directive alignment, "
    646                  "can't be less than zero");
    647 
    648   if (!Sym->isUndefined())
    649     return Error(IDLoc, "invalid symbol redefinition");
    650 
    651   // Create the zerofill Symbol with Size and Pow2Alignment
    652   //
    653   // FIXME: Arch specific.
    654   getStreamer().EmitZerofill(getContext().getMachOSection(
    655                                Segment, Section, MCSectionMachO::S_ZEROFILL,
    656                                0, SectionKind::getBSS()),
    657                              Sym, Size, 1 << Pow2Alignment);
    658 
    659   return false;
    660 }
    661 
    662 namespace llvm {
    663 
    664 MCAsmParserExtension *createDarwinAsmParser() {
    665   return new DarwinAsmParser;
    666 }
    667 
    668 }
    669