move some files out of the llvm-mc tool into the MCParser library so

other tools can link it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94131 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 2085 insertions, 0 deletions

diff --git a/lib/MC/MCParser/AsmLexer.cpp b/lib/MC/MCParser/AsmLexer.cpp
new file mode 100644
index 0000000000..0b2e68c95b
--- /dev/null
+++ b/lib/MC/MCParser/AsmLexer.cpp
@@ -0,0 +1,304 @@
+//===- AsmLexer.cpp - Lexer for Assembly Files ----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This class implements the lexer for assembly files.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MCParser/AsmLexer.h"
+#include "llvm/Support/SMLoc.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include <cerrno>
+#include <cstdio>
+#include <cstdlib>
+using namespace llvm;
+
+AsmLexer::AsmLexer(const MCAsmInfo &_MAI) : MAI(_MAI)  {
+  CurBuf = NULL;
+  CurPtr = NULL;
+  TokStart = 0;
+}
+
+AsmLexer::~AsmLexer() {
+}
+
+void AsmLexer::setBuffer(const MemoryBuffer *buf, const char *ptr) {
+  CurBuf = buf;
+  
+  if (ptr)
+    CurPtr = ptr;
+  else
+    CurPtr = CurBuf->getBufferStart();
+  
+  TokStart = 0;
+}
+
+SMLoc AsmLexer::getLoc() const {
+  return SMLoc::getFromPointer(TokStart);
+}
+
+/// ReturnError - Set the error to the specified string at the specified
+/// location.  This is defined to always return AsmToken::Error.
+AsmToken AsmLexer::ReturnError(const char *Loc, const std::string &Msg) {
+  SetError(SMLoc::getFromPointer(Loc), Msg);
+  
+  return AsmToken(AsmToken::Error, StringRef(Loc, 0));
+}
+
+int AsmLexer::getNextChar() {
+  char CurChar = *CurPtr++;
+  switch (CurChar) {
+  default:
+    return (unsigned char)CurChar;
+  case 0:
+    // A nul character in the stream is either the end of the current buffer or
+    // a random nul in the file.  Disambiguate that here.
+    if (CurPtr-1 != CurBuf->getBufferEnd())
+      return 0;  // Just whitespace.
+    
+    // Otherwise, return end of file.
+    --CurPtr;  // Another call to lex will return EOF again.  
+    return EOF;
+  }
+}
+
+/// LexIdentifier: [a-zA-Z_.][a-zA-Z0-9_$.@]*
+AsmToken AsmLexer::LexIdentifier() {
+  while (isalnum(*CurPtr) || *CurPtr == '_' || *CurPtr == '$' ||
+         *CurPtr == '.' || *CurPtr == '@')
+    ++CurPtr;
+  return AsmToken(AsmToken::Identifier, StringRef(TokStart, CurPtr - TokStart));
+}
+
+/// LexSlash: Slash: /
+///           C-Style Comment: /* ... */
+AsmToken AsmLexer::LexSlash() {
+  switch (*CurPtr) {
+  case '*': break; // C style comment.
+  case '/': return ++CurPtr, LexLineComment();
+  default:  return AsmToken(AsmToken::Slash, StringRef(CurPtr, 1));
+  }
+
+  // C Style comment.
+  ++CurPtr;  // skip the star.
+  while (1) {
+    int CurChar = getNextChar();
+    switch (CurChar) {
+    case EOF:
+      return ReturnError(TokStart, "unterminated comment");
+    case '*':
+      // End of the comment?
+      if (CurPtr[0] != '/') break;
+      
+      ++CurPtr;   // End the */.
+      return LexToken();
+    }
+  }
+}
+
+/// LexLineComment: Comment: #[^\n]*
+///                        : //[^\n]*
+AsmToken AsmLexer::LexLineComment() {
+  // FIXME: This is broken if we happen to a comment at the end of a file, which
+  // was .included, and which doesn't end with a newline.
+  int CurChar = getNextChar();
+  while (CurChar != '\n' && CurChar != '\n' && CurChar != EOF)
+    CurChar = getNextChar();
+  
+  if (CurChar == EOF)
+    return AsmToken(AsmToken::Eof, StringRef(CurPtr, 0));
+  return AsmToken(AsmToken::EndOfStatement, StringRef(CurPtr, 0));
+}
+
+
+/// LexDigit: First character is [0-9].
+///   Local Label: [0-9][:]
+///   Forward/Backward Label: [0-9][fb]
+///   Binary integer: 0b[01]+
+///   Octal integer: 0[0-7]+
+///   Hex integer: 0x[0-9a-fA-F]+
+///   Decimal integer: [1-9][0-9]*
+/// TODO: FP literal.
+AsmToken AsmLexer::LexDigit() {
+  if (*CurPtr == ':')
+    return ReturnError(TokStart, "FIXME: local label not implemented");
+  if (*CurPtr == 'f' || *CurPtr == 'b')
+    return ReturnError(TokStart, "FIXME: directional label not implemented");
+  
+  // Decimal integer: [1-9][0-9]*
+  if (CurPtr[-1] != '0') {
+    while (isdigit(*CurPtr))
+      ++CurPtr;
+    return AsmToken(AsmToken::Integer, StringRef(TokStart, CurPtr - TokStart), 
+                    strtoll(TokStart, 0, 10));
+  }
+  
+  if (*CurPtr == 'b') {
+    ++CurPtr;
+    const char *NumStart = CurPtr;
+    while (CurPtr[0] == '0' || CurPtr[0] == '1')
+      ++CurPtr;
+    
+    // Requires at least one binary digit.
+    if (CurPtr == NumStart)
+      return ReturnError(CurPtr-2, "Invalid binary number");
+    return AsmToken(AsmToken::Integer, StringRef(TokStart, CurPtr - TokStart),
+                    strtoll(NumStart, 0, 2));
+  }
+ 
+  if (*CurPtr == 'x') {
+    ++CurPtr;
+    const char *NumStart = CurPtr;
+    while (isxdigit(CurPtr[0]))
+      ++CurPtr;
+    
+    // Requires at least one hex digit.
+    if (CurPtr == NumStart)
+      return ReturnError(CurPtr-2, "Invalid hexadecimal number");
+
+    unsigned long long Result;
+    if (StringRef(TokStart, CurPtr - TokStart).getAsInteger(0, Result))
+      return ReturnError(CurPtr-2, "Invalid hexadecimal number");
+      
+    return AsmToken(AsmToken::Integer, StringRef(TokStart, CurPtr - TokStart),
+                    (int64_t)Result);
+  }
+  
+  // Must be an octal number, it starts with 0.
+  while (*CurPtr >= '0' && *CurPtr <= '7')
+    ++CurPtr;
+  return AsmToken(AsmToken::Integer, StringRef(TokStart, CurPtr - TokStart),
+                  strtoll(TokStart, 0, 8));
+}
+
+/// LexQuote: String: "..."
+AsmToken AsmLexer::LexQuote() {
+  int CurChar = getNextChar();
+  // TODO: does gas allow multiline string constants?
+  while (CurChar != '"') {
+    if (CurChar == '\\') {
+      // Allow \", etc.
+      CurChar = getNextChar();
+    }
+    
+    if (CurChar == EOF)
+      return ReturnError(TokStart, "unterminated string constant");
+
+    CurChar = getNextChar();
+  }
+  
+  return AsmToken(AsmToken::String, StringRef(TokStart, CurPtr - TokStart));
+}
+
+StringRef AsmLexer::LexUntilEndOfStatement() {
+  TokStart = CurPtr;
+
+  while (!isAtStartOfComment(*CurPtr) && // Start of line comment.
+	  *CurPtr != ';' &&  // End of statement marker.
+         *CurPtr != '\n' &&
+         *CurPtr != '\r' &&
+         (*CurPtr != 0 || CurPtr != CurBuf->getBufferEnd())) {
+    ++CurPtr;
+  }
+  return StringRef(TokStart, CurPtr-TokStart);
+}
+
+bool AsmLexer::isAtStartOfComment(char Char) {
+  // FIXME: This won't work for multi-character comment indicators like "//".
+  return Char == *MAI.getCommentString();
+}
+
+AsmToken AsmLexer::LexToken() {
+  TokStart = CurPtr;
+  // This always consumes at least one character.
+  int CurChar = getNextChar();
+  
+  if (isAtStartOfComment(CurChar))
+    return LexLineComment();
+
+  switch (CurChar) {
+  default:
+    // Handle identifier: [a-zA-Z_.][a-zA-Z0-9_$.@]*
+    if (isalpha(CurChar) || CurChar == '_' || CurChar == '.')
+      return LexIdentifier();
+    
+    // Unknown character, emit an error.
+    return ReturnError(TokStart, "invalid character in input");
+  case EOF: return AsmToken(AsmToken::Eof, StringRef(TokStart, 0));
+  case 0:
+  case ' ':
+  case '\t':
+    // Ignore whitespace.
+    return LexToken();
+  case '\n': // FALL THROUGH.
+  case '\r': // FALL THROUGH.
+  case ';': return AsmToken(AsmToken::EndOfStatement, StringRef(TokStart, 1));
+  case ':': return AsmToken(AsmToken::Colon, StringRef(TokStart, 1));
+  case '+': return AsmToken(AsmToken::Plus, StringRef(TokStart, 1));
+  case '-': return AsmToken(AsmToken::Minus, StringRef(TokStart, 1));
+  case '~': return AsmToken(AsmToken::Tilde, StringRef(TokStart, 1));
+  case '(': return AsmToken(AsmToken::LParen, StringRef(TokStart, 1));
+  case ')': return AsmToken(AsmToken::RParen, StringRef(TokStart, 1));
+  case '[': return AsmToken(AsmToken::LBrac, StringRef(TokStart, 1));
+  case ']': return AsmToken(AsmToken::RBrac, StringRef(TokStart, 1));
+  case '{': return AsmToken(AsmToken::LCurly, StringRef(TokStart, 1));
+  case '}': return AsmToken(AsmToken::RCurly, StringRef(TokStart, 1));
+  case '*': return AsmToken(AsmToken::Star, StringRef(TokStart, 1));
+  case ',': return AsmToken(AsmToken::Comma, StringRef(TokStart, 1));
+  case '$': return AsmToken(AsmToken::Dollar, StringRef(TokStart, 1));
+  case '=': 
+    if (*CurPtr == '=')
+      return ++CurPtr, AsmToken(AsmToken::EqualEqual, StringRef(TokStart, 2));
+    return AsmToken(AsmToken::Equal, StringRef(TokStart, 1));
+  case '|': 
+    if (*CurPtr == '|')
+      return ++CurPtr, AsmToken(AsmToken::PipePipe, StringRef(TokStart, 2));
+    return AsmToken(AsmToken::Pipe, StringRef(TokStart, 1));
+  case '^': return AsmToken(AsmToken::Caret, StringRef(TokStart, 1));
+  case '&': 
+    if (*CurPtr == '&')
+      return ++CurPtr, AsmToken(AsmToken::AmpAmp, StringRef(TokStart, 2));
+    return AsmToken(AsmToken::Amp, StringRef(TokStart, 1));
+  case '!': 
+    if (*CurPtr == '=')
+      return ++CurPtr, AsmToken(AsmToken::ExclaimEqual, StringRef(TokStart, 2));
+    return AsmToken(AsmToken::Exclaim, StringRef(TokStart, 1));
+  case '%': return AsmToken(AsmToken::Percent, StringRef(TokStart, 1));
+  case '/': return LexSlash();
+  case '#': return AsmToken(AsmToken::Hash, StringRef(TokStart, 1));
+  case '"': return LexQuote();
+  case '0': case '1': case '2': case '3': case '4':
+  case '5': case '6': case '7': case '8': case '9':
+    return LexDigit();
+  case '<':
+    switch (*CurPtr) {
+    case '<': return ++CurPtr, AsmToken(AsmToken::LessLess, 
+                                        StringRef(TokStart, 2));
+    case '=': return ++CurPtr, AsmToken(AsmToken::LessEqual, 
+                                        StringRef(TokStart, 2));
+    case '>': return ++CurPtr, AsmToken(AsmToken::LessGreater, 
+                                        StringRef(TokStart, 2));
+    default: return AsmToken(AsmToken::Less, StringRef(TokStart, 1));
+    }
+  case '>':
+    switch (*CurPtr) {
+    case '>': return ++CurPtr, AsmToken(AsmToken::GreaterGreater, 
+                                        StringRef(TokStart, 2));
+    case '=': return ++CurPtr, AsmToken(AsmToken::GreaterEqual, 
+                                        StringRef(TokStart, 2));
+    default: return AsmToken(AsmToken::Greater, StringRef(TokStart, 1));
+    }
+      
+  // TODO: Quoted identifiers (objc methods etc)
+  // local labels: [0-9][:]
+  // Forward/backward labels: [0-9][fb]
+  // Integers, fp constants, character constants.
+  }
+}
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
new file mode 100644
index 0000000000..e311400d78
--- /dev/null
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -0,0 +1,1781 @@
+//===- AsmParser.cpp - Parser for Assembly Files --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This class implements the parser for assembly files.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MCParser/AsmParser.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCSectionMachO.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCValue.h"
+#include "llvm/MC/MCParser/MCParsedAsmOperand.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetAsmParser.h"
+using namespace llvm;
+
+
+enum { DEFAULT_ADDRSPACE = 0 };
+
+// Mach-O section uniquing.
+//
+// FIXME: Figure out where this should live, it should be shared by
+// TargetLoweringObjectFile.
+typedef StringMap<const MCSectionMachO*> MachOUniqueMapTy;
+
+AsmParser::AsmParser(SourceMgr &_SM, MCContext &_Ctx, MCStreamer &_Out,
+                     const MCAsmInfo &_MAI) 
+  : Lexer(_MAI), Ctx(_Ctx), Out(_Out), SrcMgr(_SM), TargetParser(0),
+    CurBuffer(0), SectionUniquingMap(0) {
+  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer));
+  
+  // Debugging directives.
+  AddDirectiveHandler(".file", &AsmParser::ParseDirectiveFile);
+  AddDirectiveHandler(".line", &AsmParser::ParseDirectiveLine);
+  AddDirectiveHandler(".loc", &AsmParser::ParseDirectiveLoc);
+}
+
+
+
+AsmParser::~AsmParser() {
+  // If we have the MachO uniquing map, free it.
+  delete (MachOUniqueMapTy*)SectionUniquingMap;
+}
+
+const MCSection *AsmParser::getMachOSection(const StringRef &Segment,
+                                            const StringRef &Section,
+                                            unsigned TypeAndAttributes,
+                                            unsigned Reserved2,
+                                            SectionKind Kind) const {
+  // We unique sections by their segment/section pair.  The returned section
+  // may not have the same flags as the requested section, if so this should be
+  // diagnosed by the client as an error.
+  
+  // Create the map if it doesn't already exist.
+  if (SectionUniquingMap == 0)
+    SectionUniquingMap = new MachOUniqueMapTy();
+  MachOUniqueMapTy &Map = *(MachOUniqueMapTy*)SectionUniquingMap;
+  
+  // Form the name to look up.
+  SmallString<64> Name;
+  Name += Segment;
+  Name.push_back(',');
+  Name += Section;
+
+  // Do the lookup, if we have a hit, return it.
+  const MCSectionMachO *&Entry = Map[Name.str()];
+
+  // FIXME: This should validate the type and attributes.
+  if (Entry) return Entry;
+
+  // Otherwise, return a new section.
+  return Entry = MCSectionMachO::Create(Segment, Section, TypeAndAttributes,
+                                        Reserved2, Kind, Ctx);
+}
+
+void AsmParser::Warning(SMLoc L, const Twine &Msg) {
+  PrintMessage(L, Msg.str(), "warning");
+}
+
+bool AsmParser::Error(SMLoc L, const Twine &Msg) {
+  PrintMessage(L, Msg.str(), "error");
+  return true;
+}
+
+bool AsmParser::TokError(const char *Msg) {
+  PrintMessage(Lexer.getLoc(), Msg, "error");
+  return true;
+}
+
+void AsmParser::PrintMessage(SMLoc Loc, const std::string &Msg, 
+                             const char *Type) const {
+  SrcMgr.PrintMessage(Loc, Msg, Type);
+}
+                  
+bool AsmParser::EnterIncludeFile(const std::string &Filename) {
+  int NewBuf = SrcMgr.AddIncludeFile(Filename, Lexer.getLoc());
+  if (NewBuf == -1)
+    return true;
+  
+  CurBuffer = NewBuf;
+  
+  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer));
+  
+  return false;
+}
+                  
+const AsmToken &AsmParser::Lex() {
+  const AsmToken *tok = &Lexer.Lex();
+  
+  if (tok->is(AsmToken::Eof)) {
+    // If this is the end of an included file, pop the parent file off the
+    // include stack.
+    SMLoc ParentIncludeLoc = SrcMgr.getParentIncludeLoc(CurBuffer);
+    if (ParentIncludeLoc != SMLoc()) {
+      CurBuffer = SrcMgr.FindBufferContainingLoc(ParentIncludeLoc);
+      Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer), 
+                      ParentIncludeLoc.getPointer());
+      tok = &Lexer.Lex();
+    }
+  }
+    
+  if (tok->is(AsmToken::Error))
+    PrintMessage(Lexer.getErrLoc(), Lexer.getErr(), "error");
+  
+  return *tok;
+}
+
+bool AsmParser::Run() {
+  // Create the initial section.
+  //
+  // FIXME: Support -n.
+  // FIXME: Target hook & command line option for initial section.
+  Out.SwitchSection(getMachOSection("__TEXT", "__text",
+                                    MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
+                                    0, SectionKind()));
+
+
+  // Prime the lexer.
+  Lex();
+  
+  bool HadError = false;
+  
+  AsmCond StartingCondState = TheCondState;
+
+  // While we have input, parse each statement.
+  while (Lexer.isNot(AsmToken::Eof)) {
+    // Handle conditional assembly here before calling ParseStatement()
+    if (Lexer.getKind() == AsmToken::Identifier) {
+      // If we have an identifier, handle it as the key symbol.
+      AsmToken ID = getTok();
+      SMLoc IDLoc = ID.getLoc();
+      StringRef IDVal = ID.getString();
+
+      if (IDVal == ".if" ||
+          IDVal == ".elseif" ||
+          IDVal == ".else" ||
+          IDVal == ".endif") {
+        if (!ParseConditionalAssemblyDirectives(IDVal, IDLoc))
+          continue;
+	HadError = true;
+	EatToEndOfStatement();
+	continue;
+      }
+    }
+    if (TheCondState.Ignore) {
+      EatToEndOfStatement();
+      continue;
+    }
+
+    if (!ParseStatement()) continue;
+  
+    // We had an error, remember it and recover by skipping to the next line.
+    HadError = true;
+    EatToEndOfStatement();
+  }
+
+  if (TheCondState.TheCond != StartingCondState.TheCond ||
+      TheCondState.Ignore != StartingCondState.Ignore)
+    return TokError("unmatched .ifs or .elses");
+  
+  if (!HadError)  
+    Out.Finish();
+
+  return HadError;
+}
+
+/// ParseConditionalAssemblyDirectives - parse the conditional assembly
+/// directives
+bool AsmParser::ParseConditionalAssemblyDirectives(StringRef Directive,
+                                                   SMLoc DirectiveLoc) {
+  if (Directive == ".if")
+    return ParseDirectiveIf(DirectiveLoc);
+  if (Directive == ".elseif")
+    return ParseDirectiveElseIf(DirectiveLoc);
+  if (Directive == ".else")
+    return ParseDirectiveElse(DirectiveLoc);
+  if (Directive == ".endif")
+    return ParseDirectiveEndIf(DirectiveLoc);
+  return true;
+}
+
+/// EatToEndOfStatement - Throw away the rest of the line for testing purposes.
+void AsmParser::EatToEndOfStatement() {
+  while (Lexer.isNot(AsmToken::EndOfStatement) &&
+         Lexer.isNot(AsmToken::Eof))
+    Lex();
+  
+  // Eat EOL.
+  if (Lexer.is(AsmToken::EndOfStatement))
+    Lex();
+}
+
+
+/// ParseParenExpr - Parse a paren expression and return it.
+/// NOTE: This assumes the leading '(' has already been consumed.
+///
+/// parenexpr ::= expr)
+///
+bool AsmParser::ParseParenExpr(const MCExpr *&Res, SMLoc &EndLoc) {
+  if (ParseExpression(Res)) return true;
+  if (Lexer.isNot(AsmToken::RParen))
+    return TokError("expected ')' in parentheses expression");
+  EndLoc = Lexer.getLoc();
+  Lex();
+  return false;
+}
+
+MCSymbol *AsmParser::CreateSymbol(StringRef Name) {
+  if (MCSymbol *S = Ctx.LookupSymbol(Name))
+    return S;
+
+  // If the label starts with L it is an assembler temporary label.
+  if (Name.startswith("L"))
+    return Ctx.CreateTemporarySymbol(Name);
+
+  return Ctx.CreateSymbol(Name);
+}
+
+/// ParsePrimaryExpr - Parse a primary expression and return it.
+///  primaryexpr ::= (parenexpr
+///  primaryexpr ::= symbol
+///  primaryexpr ::= number
+///  primaryexpr ::= ~,+,- primaryexpr
+bool AsmParser::ParsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
+  switch (Lexer.getKind()) {
+  default:
+    return TokError("unknown token in expression");
+  case AsmToken::Exclaim:
+    Lex(); // Eat the operator.
+    if (ParsePrimaryExpr(Res, EndLoc))
+      return true;
+    Res = MCUnaryExpr::CreateLNot(Res, getContext());
+    return false;
+  case AsmToken::String:
+  case AsmToken::Identifier: {
+    // This is a symbol reference.
+    MCSymbol *Sym = CreateSymbol(getTok().getIdentifier());
+    EndLoc = Lexer.getLoc();
+    Lex(); // Eat identifier.
+
+    // If this is an absolute variable reference, substitute it now to preserve
+    // semantics in the face of reassignment.
+    if (Sym->getValue() && isa<MCConstantExpr>(Sym->getValue())) {
+      Res = Sym->getValue();
+      return false;
+    }
+
+    // Otherwise create a symbol ref.
+    Res = MCSymbolRefExpr::Create(Sym, getContext());
+    return false;
+  }
+  case AsmToken::Integer:
+    Res = MCConstantExpr::Create(getTok().getIntVal(), getContext());
+    EndLoc = Lexer.getLoc();
+    Lex(); // Eat token.
+    return false;
+  case AsmToken::LParen:
+    Lex(); // Eat the '('.
+    return ParseParenExpr(Res, EndLoc);
+  case AsmToken::Minus:
+    Lex(); // Eat the operator.
+    if (ParsePrimaryExpr(Res, EndLoc))
+      return true;
+    Res = MCUnaryExpr::CreateMinus(Res, getContext());
+    return false;
+  case AsmToken::Plus:
+    Lex(); // Eat the operator.
+    if (ParsePrimaryExpr(Res, EndLoc))
+      return true;
+    Res = MCUnaryExpr::CreatePlus(Res, getContext());
+    return false;
+  case AsmToken::Tilde:
+    Lex(); // Eat the operator.
+    if (ParsePrimaryExpr(Res, EndLoc))
+      return true;
+    Res = MCUnaryExpr::CreateNot(Res, getContext());
+    return false;
+  }
+}
+
+bool AsmParser::ParseExpression(const MCExpr *&Res) {
+  SMLoc EndLoc;
+  return ParseExpression(Res, EndLoc);
+}
+
+/// ParseExpression - Parse an expression and return it.
+/// 
+///  expr ::= expr +,- expr          -> lowest.
+///  expr ::= expr |,^,&,! expr      -> middle.
+///  expr ::= expr *,/,%,<<,>> expr  -> highest.
+///  expr ::= primaryexpr
+///
+bool AsmParser::ParseExpression(const MCExpr *&Res, SMLoc &EndLoc) {
+  Res = 0;
+  return ParsePrimaryExpr(Res, EndLoc) ||
+         ParseBinOpRHS(1, Res, EndLoc);
+}
+
+bool AsmParser::ParseParenExpression(const MCExpr *&Res, SMLoc &EndLoc) {
+  if (ParseParenExpr(Res, EndLoc))
+    return true;
+
+  return false;
+}
+
+bool AsmParser::ParseAbsoluteExpression(int64_t &Res) {
+  const MCExpr *Expr;
+  
+  SMLoc StartLoc = Lexer.getLoc();
+  if (ParseExpression(Expr))
+    return true;
+
+  if (!Expr->EvaluateAsAbsolute(Res))
+    return Error(StartLoc, "expected absolute expression");
+
+  return false;
+}
+
+static unsigned getBinOpPrecedence(AsmToken::TokenKind K, 
+                                   MCBinaryExpr::Opcode &Kind) {
+  switch (K) {
+  default:
+    return 0;    // not a binop.
+
+    // Lowest Precedence: &&, ||
+  case AsmToken::AmpAmp:
+    Kind = MCBinaryExpr::LAnd;
+    return 1;
+  case AsmToken::PipePipe:
+    Kind = MCBinaryExpr::LOr;
+    return 1;
+
+    // Low Precedence: +, -, ==, !=, <>, <, <=, >, >=
+  case AsmToken::Plus:
+    Kind = MCBinaryExpr::Add;
+    return 2;
+  case AsmToken::Minus:
+    Kind = MCBinaryExpr::Sub;
+    return 2;
+  case AsmToken::EqualEqual:
+    Kind = MCBinaryExpr::EQ;
+    return 2;
+  case AsmToken::ExclaimEqual:
+  case AsmToken::LessGreater:
+    Kind = MCBinaryExpr::NE;
+    return 2;
+  case AsmToken::Less:
+    Kind = MCBinaryExpr::LT;
+    return 2;
+  case AsmToken::LessEqual:
+    Kind = MCBinaryExpr::LTE;
+    return 2;
+  case AsmToken::Greater:
+    Kind = MCBinaryExpr::GT;
+    return 2;
+  case AsmToken::GreaterEqual:
+    Kind = MCBinaryExpr::GTE;
+    return 2;
+
+    // Intermediate Precedence: |, &, ^
+    //
+    // FIXME: gas seems to support '!' as an infix operator?
+  case AsmToken::Pipe:
+    Kind = MCBinaryExpr::Or;
+    return 3;
+  case AsmToken::Caret:
+    Kind = MCBinaryExpr::Xor;
+    return 3;
+  case AsmToken::Amp:
+    Kind = MCBinaryExpr::And;
+    return 3;
+
+    // Highest Precedence: *, /, %, <<, >>
+  case AsmToken::Star:
+    Kind = MCBinaryExpr::Mul;
+    return 4;
+  case AsmToken::Slash:
+    Kind = MCBinaryExpr::Div;
+    return 4;
+  case AsmToken::Percent:
+    Kind = MCBinaryExpr::Mod;
+    return 4;
+  case AsmToken::LessLess:
+    Kind = MCBinaryExpr::Shl;
+    return 4;
+  case AsmToken::GreaterGreater:
+    Kind = MCBinaryExpr::Shr;
+    return 4;
+  }
+}
+
+
+/// ParseBinOpRHS - Parse all binary operators with precedence >= 'Precedence'.
+/// Res contains the LHS of the expression on input.
+bool AsmParser::ParseBinOpRHS(unsigned Precedence, const MCExpr *&Res,
+                              SMLoc &EndLoc) {
+  while (1) {
+    MCBinaryExpr::Opcode Kind = MCBinaryExpr::Add;
+    unsigned TokPrec = getBinOpPrecedence(Lexer.getKind(), Kind);
+    
+    // If the next token is lower precedence than we are allowed to eat, return
+    // successfully with what we ate already.
+    if (TokPrec < Precedence)
+      return false;
+    
+    Lex();
+    
+    // Eat the next primary expression.
+    const MCExpr *RHS;
+    if (ParsePrimaryExpr(RHS, EndLoc)) return true;
+    
+    // If BinOp binds less tightly with RHS than the operator after RHS, let
+    // the pending operator take RHS as its LHS.
+    MCBinaryExpr::Opcode Dummy;
+    unsigned NextTokPrec = getBinOpPrecedence(Lexer.getKind(), Dummy);
+    if (TokPrec < NextTokPrec) {
+      if (ParseBinOpRHS(Precedence+1, RHS, EndLoc)) return true;
+    }
+
+    // Merge LHS and RHS according to operator.
+    Res = MCBinaryExpr::Create(Kind, Res, RHS, getContext());
+  }
+}
+
+  
+  
+  
+/// ParseStatement:
+///   ::= EndOfStatement
+///   ::= Label* Directive ...Operands... EndOfStatement
+///   ::= Label* Identifier OperandList* EndOfStatement
+bool AsmParser::ParseStatement() {
+  if (Lexer.is(AsmToken::EndOfStatement)) {
+    Lex();
+    return false;
+  }
+
+  // Statements always start with an identifier.
+  AsmToken ID = getTok();
+  SMLoc IDLoc = ID.getLoc();
+  StringRef IDVal;
+  if (ParseIdentifier(IDVal))
+    return TokError("unexpected token at start of statement");
+
+  // FIXME: Recurse on local labels?
+
+  // See what kind of statement we have.
+  switch (Lexer.getKind()) {
+  case AsmToken::Colon: {
+    // identifier ':'   -> Label.
+    Lex();
+
+    // Diagnose attempt to use a variable as a label.
+    //
+    // FIXME: Diagnostics. Note the location of the definition as a label.
+    // FIXME: This doesn't diagnose assignment to a symbol which has been
+    // implicitly marked as external.
+    MCSymbol *Sym = CreateSymbol(IDVal);
+    if (!Sym->isUndefined())
+      return Error(IDLoc, "invalid symbol redefinition");
+    
+    // Emit the label.
+    Out.EmitLabel(Sym);
+   
+    return ParseStatement();
+  }
+
+  case AsmToken::Equal:
+    // identifier '=' ... -> assignment statement
+    Lex();
+
+    return ParseAssignment(IDVal);
+
+  default: // Normal instruction or directive.
+    break;
+  }
+  
+  // Otherwise, we have a normal instruction or directive.  
+  if (IDVal[0] == '.') {
+    // FIXME: This should be driven based on a hash lookup and callback.
+    if (IDVal == ".section")
+      return ParseDirectiveDarwinSection();
+    if (IDVal == ".text")
+      // FIXME: This changes behavior based on the -static flag to the
+      // assembler.
+      return ParseDirectiveSectionSwitch("__TEXT", "__text",
+                                     MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS);
+    if (IDVal == ".const")
+      return ParseDirectiveSectionSwitch("__TEXT", "__const");
+    if (IDVal == ".static_const")
+      return ParseDirectiveSectionSwitch("__TEXT", "__static_const");
+    if (IDVal == ".cstring")
+      return ParseDirectiveSectionSwitch("__TEXT","__cstring", 
+                                         MCSectionMachO::S_CSTRING_LITERALS);
+    if (IDVal == ".literal4")
+      return ParseDirectiveSectionSwitch("__TEXT", "__literal4",
+                                         MCSectionMachO::S_4BYTE_LITERALS,
+                                         4);
+    if (IDVal == ".literal8")
+      return ParseDirectiveSectionSwitch("__TEXT", "__literal8",
+                                         MCSectionMachO::S_8BYTE_LITERALS,
+                                         8);
+    if (IDVal == ".literal16")
+      return ParseDirectiveSectionSwitch("__TEXT","__literal16",
+                                         MCSectionMachO::S_16BYTE_LITERALS,
+                                         16);
+    if (IDVal == ".constructor")
+      return ParseDirectiveSectionSwitch("__TEXT","__constructor");
+    if (IDVal == ".destructor")
+      return ParseDirectiveSectionSwitch("__TEXT","__destructor");
+    if (IDVal == ".fvmlib_init0")
+      return ParseDirectiveSectionSwitch("__TEXT","__fvmlib_init0");
+    if (IDVal == ".fvmlib_init1")
+      return ParseDirectiveSectionSwitch("__TEXT","__fvmlib_init1");
+
+    // FIXME: The assembler manual claims that this has the self modify code
+    // flag, at least on x86-32, but that does not appear to be correct.
+    if (IDVal == ".symbol_stub")
+      return ParseDirectiveSectionSwitch("__TEXT","__symbol_stub",
+                                         MCSectionMachO::S_SYMBOL_STUBS |
+                                       MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
+                                          // FIXME: Different on PPC and ARM.
+                                         0, 16);
+    // FIXME: PowerPC only?
+    if (IDVal == ".picsymbol_stub")
+      return ParseDirectiveSectionSwitch("__TEXT","__picsymbol_stub",
+                                         MCSectionMachO::S_SYMBOL_STUBS |
+                                       MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
+                                         0, 26);
+    if (IDVal == ".data")
+      return ParseDirectiveSectionSwitch("__DATA", "__data");
+    if (IDVal == ".static_data")
+      return ParseDirectiveSectionSwitch("__DATA", "__static_data");
+
+    // FIXME: The section names of these two are misspelled in the assembler
+    // manual.
+    if (IDVal == ".non_lazy_symbol_pointer")
+      return ParseDirectiveSectionSwitch("__DATA", "__nl_symbol_ptr",
+                                     MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
+                                         4);
+    if (IDVal == ".lazy_symbol_pointer")
+      return ParseDirectiveSectionSwitch("__DATA", "__la_symbol_ptr",
+                                         MCSectionMachO::S_LAZY_SYMBOL_POINTERS,
+                                         4);
+
+    if (IDVal == ".dyld")
+      return ParseDirectiveSectionSwitch("__DATA", "__dyld");
+    if (IDVal == ".mod_init_func")
+      return ParseDirectiveSectionSwitch("__DATA", "__mod_init_func",
+                                       MCSectionMachO::S_MOD_INIT_FUNC_POINTERS,
+                                         4);
+    if (IDVal == ".mod_term_func")
+      return ParseDirectiveSectionSwitch("__DATA", "__mod_term_func",
+                                       MCSectionMachO::S_MOD_TERM_FUNC_POINTERS,
+                                         4);
+    if (IDVal == ".const_data")
+      return ParseDirectiveSectionSwitch("__DATA", "__const");
+    
+    
+    if (IDVal == ".objc_class")
+      return ParseDirectiveSectionSwitch("__OBJC", "__class", 
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_meta_class")
+      return ParseDirectiveSectionSwitch("__OBJC", "__meta_class",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_cat_cls_meth")
+      return ParseDirectiveSectionSwitch("__OBJC", "__cat_cls_meth",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_cat_inst_meth")
+      return ParseDirectiveSectionSwitch("__OBJC", "__cat_inst_meth",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_protocol")
+      return ParseDirectiveSectionSwitch("__OBJC", "__protocol",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_string_object")
+      return ParseDirectiveSectionSwitch("__OBJC", "__string_object",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_cls_meth")
+      return ParseDirectiveSectionSwitch("__OBJC", "__cls_meth",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_inst_meth")
+      return ParseDirectiveSectionSwitch("__OBJC", "__inst_meth",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_cls_refs")
+      return ParseDirectiveSectionSwitch("__OBJC", "__cls_refs",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP |
+                                         MCSectionMachO::S_LITERAL_POINTERS,
+                                         4);
+    if (IDVal == ".objc_message_refs")
+      return ParseDirectiveSectionSwitch("__OBJC", "__message_refs",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP |
+                                         MCSectionMachO::S_LITERAL_POINTERS,
+                                         4);
+    if (IDVal == ".objc_symbols")
+      return ParseDirectiveSectionSwitch("__OBJC", "__symbols",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_category")
+      return ParseDirectiveSectionSwitch("__OBJC", "__category",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_class_vars")
+      return ParseDirectiveSectionSwitch("__OBJC", "__class_vars",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_instance_vars")
+      return ParseDirectiveSectionSwitch("__OBJC", "__instance_vars",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_module_info")
+      return ParseDirectiveSectionSwitch("__OBJC", "__module_info",
+                                         MCSectionMachO::S_ATTR_NO_DEAD_STRIP);
+    if (IDVal == ".objc_class_names")
+      return ParseDirectiveSectionSwitch("__TEXT", "__cstring",
+                                         MCSectionMachO::S_CSTRING_LITERALS);
+    if (IDVal == ".objc_meth_var_types")
+      return ParseDirectiveSectionSwitch("__TEXT", "__cstring",
+                                         MCSectionMachO::S_CSTRING_LITERALS);
+    if (IDVal == ".objc_meth_var_names")
+      return ParseDirectiveSectionSwitch("__TEXT", "__cstring",
+                                         MCSectionMachO::S_CSTRING_LITERALS);
+    if (IDVal == ".objc_selector_strs")
+      return ParseDirectiveSectionSwitch("__OBJC", "__selector_strs",
+                                         MCSectionMachO::S_CSTRING_LITERALS);
+    
+    // Assembler features
+    if (IDVal == ".set")
+      return ParseDirectiveSet();
+
+    // Data directives
+
+    if (IDVal == ".ascii")
+      return ParseDirectiveAscii(false);
+    if (IDVal == ".asciz")
+      return ParseDirectiveAscii(true);
+
+    if (IDVal == ".byte")
+      return ParseDirectiveValue(1);
+    if (IDVal == ".short")
+      return ParseDirectiveValue(2);
+    if (IDVal == ".long")
+      return ParseDirectiveValue(4);
+    if (IDVal == ".quad")
+      return ParseDirectiveValue(8);
+
+    // FIXME: Target hooks for IsPow2.
+    if (IDVal == ".align")
+      return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/1);
+    if (IDVal == ".align32")
+      return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/4);
+    if (IDVal == ".balign")
+      return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/1);
+    if (IDVal == ".balignw")
+      return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/2);
+    if (IDVal == ".balignl")
+      return ParseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/4);
+    if (IDVal == ".p2align")
+      return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/1);
+    if (IDVal == ".p2alignw")
+      return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/2);
+    if (IDVal == ".p2alignl")
+      return ParseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/4);
+
+    if (IDVal == ".org")
+      return ParseDirectiveOrg();
+
+    if (IDVal == ".fill")
+      return ParseDirectiveFill();
+    if (IDVal == ".space")
+      return ParseDirectiveSpace();
+
+    // Symbol attribute directives
+
+    if (IDVal == ".globl" || IDVal == ".global")
+      return ParseDirectiveSymbolAttribute(MCStreamer::Global);
+    if (IDVal == ".hidden")
+      return ParseDirectiveSymbolAttribute(MCStreamer::Hidden);
+    if (IDVal == ".indirect_symbol")
+      return ParseDirectiveSymbolAttribute(MCStreamer::IndirectSymbol);
+    if (IDVal == ".internal")
+      return ParseDirectiveSymbolAttribute(MCStreamer::Internal);
+    if (IDVal == ".lazy_reference")
+      return ParseDirectiveSymbolAttribute(MCStreamer::LazyReference);
+    if (IDVal == ".no_dead_strip")
+      return ParseDirectiveSymbolAttribute(MCStreamer::NoDeadStrip);
+    if (IDVal == ".private_extern")
+      return ParseDirectiveSymbolAttribute(MCStreamer::PrivateExtern);
+    if (IDVal == ".protected")
+      return ParseDirectiveSymbolAttribute(MCStreamer::Protected);
+    if (IDVal == ".reference")
+      return ParseDirectiveSymbolAttribute(MCStreamer::Reference);
+    if (IDVal == ".weak")
+      return ParseDirectiveSymbolAttribute(MCStreamer::Weak);
+    if (IDVal == ".weak_definition")
+      return ParseDirectiveSymbolAttribute(MCStreamer::WeakDefinition);
+    if (IDVal == ".weak_reference")
+      return ParseDirectiveSymbolAttribute(MCStreamer::WeakReference);
+
+    if (IDVal == ".comm")
+      return ParseDirectiveComm(/*IsLocal=*/false);
+    if (IDVal == ".lcomm")
+      return ParseDirectiveComm(/*IsLocal=*/true);
+    if (IDVal == ".zerofill")
+      return ParseDirectiveDarwinZerofill();
+    if (IDVal == ".desc")
+      return ParseDirectiveDarwinSymbolDesc();
+    if (IDVal == ".lsym")
+      return ParseDirectiveDarwinLsym();
+
+    if (IDVal == ".subsections_via_symbols")
+      return ParseDirectiveDarwinSubsectionsViaSymbols();
+    if (IDVal == ".abort")
+      return ParseDirectiveAbort();
+    if (IDVal == ".include")
+      return ParseDirectiveInclude();
+    if (IDVal == ".dump")
+      return ParseDirectiveDarwinDumpOrLoad(IDLoc, /*IsDump=*/true);
+    if (IDVal == ".load")
+      return ParseDirectiveDarwinDumpOrLoad(IDLoc, /*IsLoad=*/false);
+
+    // Look up the handler in the handler table, 
+    bool(AsmParser::*Handler)(StringRef, SMLoc) = DirectiveMap[IDVal];
+    if (Handler)
+      return (this->*Handler)(IDVal, IDLoc);
+    
+    // Target hook for parsing target specific directives.
+    if (!getTargetParser().ParseDirective(ID))
+      return false;
+
+    Warning(IDLoc, "ignoring directive for now");
+    EatToEndOfStatement();
+    return false;
+  }
+
+  
+  SmallVector<MCParsedAsmOperand*, 8> ParsedOperands;
+  if (getTargetParser().ParseInstruction(IDVal, IDLoc, ParsedOperands))
+    // FIXME: Leaking ParsedOperands on failure.
+    return true;
+  
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    // FIXME: Leaking ParsedOperands on failure.
+    return TokError("unexpected token in argument list");
+
+  // Eat the end of statement marker.
+  Lex();
+  
+
+  MCInst Inst;
+
+  bool MatchFail = getTargetParser().MatchInstruction(ParsedOperands, Inst);
+
+  // Free any parsed operands.
+  for (unsigned i = 0, e = ParsedOperands.size(); i != e; ++i)
+    delete ParsedOperands[i];
+
+  if (MatchFail) {
+    // FIXME: We should give nicer diagnostics about the exact failure.
+    Error(IDLoc, "unrecognized instruction");
+    return true;
+  }
+  
+  // Instruction is good, process it.
+  Out.EmitInstruction(Inst);
+  
+  // Skip to end of line for now.
+  return false;
+}
+
+bool AsmParser::ParseAssignment(const StringRef &Name) {
+  // FIXME: Use better location, we should use proper tokens.
+  SMLoc EqualLoc = Lexer.getLoc();
+
+  const MCExpr *Value;
+  SMLoc StartLoc = Lexer.getLoc();
+  if (ParseExpression(Value))
+    return true;
+  
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in assignment");
+
+  // Eat the end of statement marker.
+  Lex();
+
+  // Validate that the LHS is allowed to be a variable (either it has not been
+  // used as a symbol, or it is an absolute symbol).
+  MCSymbol *Sym = getContext().LookupSymbol(Name);
+  if (Sym) {
+    // Diagnose assignment to a label.
+    //
+    // FIXME: Diagnostics. Note the location of the definition as a label.
+    // FIXME: Diagnose assignment to protected identifier (e.g., register name).
+    if (!Sym->isUndefined() && !Sym->isAbsolute())
+      return Error(EqualLoc, "redefinition of '" + Name + "'");
+    else if (!Sym->isVariable())
+      return Error(EqualLoc, "invalid assignment to '" + Name + "'");
+    else if (!isa<MCConstantExpr>(Sym->getValue()))
+      return Error(EqualLoc, "invalid reassignment of non-absolute variable '" +
+                   Name + "'");
+  } else
+    Sym = CreateSymbol(Name);
+
+  // FIXME: Handle '.'.
+
+  // Do the assignment.
+  Out.EmitAssignment(Sym, Value);
+
+  return false;
+}
+
+/// ParseIdentifier:
+///   ::= identifier
+///   ::= string
+bool AsmParser::ParseIdentifier(StringRef &Res) {
+  if (Lexer.isNot(AsmToken::Identifier) &&
+      Lexer.isNot(AsmToken::String))
+    return true;
+
+  Res = getTok().getIdentifier();
+
+  Lex(); // Consume the identifier token.
+
+  return false;
+}
+
+/// ParseDirectiveSet:
+///   ::= .set identifier ',' expression
+bool AsmParser::ParseDirectiveSet() {
+  StringRef Name;
+
+  if (ParseIdentifier(Name))
+    return TokError("expected identifier after '.set' directive");
+  
+  if (Lexer.isNot(AsmToken::Comma))
+    return TokError("unexpected token in '.set'");
+  Lex();
+
+  return ParseAssignment(Name);
+}
+
+/// ParseDirectiveSection:
+///   ::= .section identifier (',' identifier)*
+/// FIXME: This should actually parse out the segment, section, attributes and
+/// sizeof_stub fields.
+bool AsmParser::ParseDirectiveDarwinSection() {
+  SMLoc Loc = Lexer.getLoc();
+
+  StringRef SectionName;
+  if (ParseIdentifier(SectionName))
+    return Error(Loc, "expected identifier after '.section' directive");
+
+  // Verify there is a following comma.
+  if (!Lexer.is(AsmToken::Comma))
+    return TokError("unexpected token in '.section' directive");
+
+  std::string SectionSpec = SectionName;
+  SectionSpec += ",";
+
+  // Add all the tokens until the end of the line, ParseSectionSpecifier will
+  // handle this.
+  StringRef EOL = Lexer.LexUntilEndOfStatement();
+  SectionSpec.append(EOL.begin(), EOL.end());
+
+  Lex();
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.section' directive");
+  Lex();
+
+
+  StringRef Segment, Section;
+  unsigned TAA, StubSize;
+  std::string ErrorStr = 
+    MCSectionMachO::ParseSectionSpecifier(SectionSpec, Segment, Section,
+                                          TAA, StubSize);
+  
+  if (!ErrorStr.empty())
+    return Error(Loc, ErrorStr.c_str());
+  
+  // FIXME: Arch specific.
+  Out.SwitchSection(getMachOSection(Segment, Section, TAA, StubSize,
+                                    SectionKind()));
+  return false;
+}
+
+/// ParseDirectiveSectionSwitch - 
+bool AsmParser::ParseDirectiveSectionSwitch(const char *Segment,
+                                            const char *Section,
+                                            unsigned TAA, unsigned Align,
+                                            unsigned StubSize) {
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in section switching directive");
+  Lex();
+  
+  // FIXME: Arch specific.
+  Out.SwitchSection(getMachOSection(Segment, Section, TAA, StubSize,
+                                    SectionKind()));
+
+  // Set the implicit alignment, if any.
+  //
+  // FIXME: This isn't really what 'as' does; I think it just uses the implicit
+  // alignment on the section (e.g., if one manually inserts bytes into the
+  // section, then just issueing the section switch directive will not realign
+  // the section. However, this is arguably more reasonable behavior, and there
+  // is no good reason for someone to intentionally emit incorrectly sized
+  // values into the implicitly aligned sections.
+  if (Align)
+    Out.EmitValueToAlignment(Align, 0, 1, 0);
+
+  return false;
+}
+
+bool AsmParser::ParseEscapedString(std::string &Data) {
+  assert(Lexer.is(AsmToken::String) && "Unexpected current token!");
+
+  Data = "";
+  StringRef Str = getTok().getStringContents();
+  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
+    if (Str[i] != '\\') {
+      Data += Str[i];
+      continue;
+    }
+
+    // Recognize escaped characters. Note that this escape semantics currently
+    // loosely follows Darwin 'as'. Notably, it doesn't support hex escapes.
+    ++i;
+    if (i == e)
+      return TokError("unexpected backslash at end of string");
+
+    // Recognize octal sequences.
+    if ((unsigned) (Str[i] - '0') <= 7) {
+      // Consume up to three octal characters.
+      unsigned Value = Str[i] - '0';
+
+      if (i + 1 != e && ((unsigned) (Str[i + 1] - '0')) <= 7) {
+        ++i;
+        Value = Value * 8 + (Str[i] - '0');
+
+        if (i + 1 != e && ((unsigned) (Str[i + 1] - '0')) <= 7) {
+          ++i;
+          Value = Value * 8 + (Str[i] - '0');
+        }
+      }
+
+      if (Value > 255)
+        return TokError("invalid octal escape sequence (out of range)");
+
+      Data += (unsigned char) Value;
+      continue;
+    }
+
+    // Otherwise recognize individual escapes.
+    switch (Str[i]) {
+    default:
+      // Just reject invalid escape sequences for now.
+      return TokError("invalid escape sequence (unrecognized character)");
+
+    case 'b': Data += '\b'; break;
+    case 'f': Data += '\f'; break;
+    case 'n': Data += '\n'; break;
+    case 'r': Data += '\r'; break;
+    case 't': Data += '\t'; break;
+    case '"': Data += '"'; break;
+    case '\\': Data += '\\'; break;
+    }
+  }
+
+  return false;
+}
+
+/// ParseDirectiveAscii:
+///   ::= ( .ascii | .asciz ) [ "string" ( , "string" )* ]
+bool AsmParser::ParseDirectiveAscii(bool ZeroTerminated) {
+  if (Lexer.isNot(AsmToken::EndOfStatement)) {
+    for (;;) {
+      if (Lexer.isNot(AsmToken::String))
+        return TokError("expected string in '.ascii' or '.asciz' directive");
+      
+      std::string Data;
+      if (ParseEscapedString(Data))
+        return true;
+      
+      Out.EmitBytes(Data, DEFAULT_ADDRSPACE);
+      if (ZeroTerminated)
+        Out.EmitBytes(StringRef("\0", 1), DEFAULT_ADDRSPACE);
+      
+      Lex();
+      
+      if (Lexer.is(AsmToken::EndOfStatement))
+        break;
+
+      if (Lexer.isNot(AsmToken::Comma))
+        return TokError("unexpected token in '.ascii' or '.asciz' directive");
+      Lex();
+    }
+  }
+
+  Lex();
+  return false;
+}
+
+/// ParseDirectiveValue
+///  ::= (.byte | .short | ... ) [ expression (, expression)* ]
+bool AsmParser::ParseDirectiveValue(unsigned Size) {
+  if (Lexer.isNot(AsmToken::EndOfStatement)) {
+    for (;;) {
+      const MCExpr *Value;
+      SMLoc ATTRIBUTE_UNUSED StartLoc = Lexer.getLoc();
+      if (ParseExpression(Value))
+        return true;
+
+      Out.EmitValue(Value, Size, DEFAULT_ADDRSPACE);
+
+      if (Lexer.is(AsmToken::EndOfStatement))
+        break;
+      
+      // FIXME: Improve diagnostic.
+      if (Lexer.isNot(AsmToken::Comma))
+        return TokError("unexpected token in directive");
+      Lex();
+    }
+  }
+
+  Lex();
+  return false;
+}
+
+/// ParseDirectiveSpace
+///  ::= .space expression [ , expression ]
+bool AsmParser::ParseDirectiveSpace() {
+  int64_t NumBytes;
+  if (ParseAbsoluteExpression(NumBytes))
+    return true;
+
+  int64_t FillExpr = 0;
+  bool HasFillExpr = false;
+  if (Lexer.isNot(AsmToken::EndOfStatement)) {
+    if (Lexer.isNot(AsmToken::Comma))
+      return TokError("unexpected token in '.space' directive");
+    Lex();
+    
+    if (ParseAbsoluteExpression(FillExpr))
+      return true;
+
+    HasFillExpr = true;
+
+    if (Lexer.isNot(AsmToken::EndOfStatement))
+      return TokError("unexpected token in '.space' directive");
+  }
+
+  Lex();
+
+  if (NumBytes <= 0)
+    return TokError("invalid number of bytes in '.space' directive");
+
+  // FIXME: Sometimes the fill expr is 'nop' if it isn't supplied, instead of 0.
+  Out.EmitFill(NumBytes, FillExpr, DEFAULT_ADDRSPACE);
+
+  return false;
+}
+
+/// ParseDirectiveFill
+///  ::= .fill expression , expression , expression
+bool AsmParser::ParseDirectiveFill() {
+  int64_t NumValues;
+  if (ParseAbsoluteExpression(NumValues))
+    return true;
+
+  if (Lexer.isNot(AsmToken::Comma))
+    return TokError("unexpected token in '.fill' directive");
+  Lex();
+  
+  int64_t FillSize;
+  if (ParseAbsoluteExpression(FillSize))
+    return true;
+
+  if (Lexer.isNot(AsmToken::Comma))
+    return TokError("unexpected token in '.fill' directive");
+  Lex();
+  
+  int64_t FillExpr;
+  if (ParseAbsoluteExpression(FillExpr))
+    return true;
+
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.fill' directive");
+  
+  Lex();
+
+  if (FillSize != 1 && FillSize != 2 && FillSize != 4 && FillSize != 8)
+    return TokError("invalid '.fill' size, expected 1, 2, 4, or 8");
+
+  for (uint64_t i = 0, e = NumValues; i != e; ++i)
+    Out.EmitValue(MCConstantExpr::Create(FillExpr, getContext()), FillSize,
+                  DEFAULT_ADDRSPACE);
+
+  return false;
+}
+
+/// ParseDirectiveOrg
+///  ::= .org expression [ , expression ]
+bool AsmParser::ParseDirectiveOrg() {
+  const MCExpr *Offset;
+  SMLoc StartLoc = Lexer.getLoc();
+  if (ParseExpression(Offset))
+    return true;
+
+  // Parse optional fill expression.
+  int64_t FillExpr = 0;
+  if (Lexer.isNot(AsmToken::EndOfStatement)) {
+    if (Lexer.isNot(AsmToken::Comma))
+      return TokError("unexpected token in '.org' directive");
+    Lex();
+    
+    if (ParseAbsoluteExpression(FillExpr))
+      return true;
+
+    if (Lexer.isNot(AsmToken::EndOfStatement))
+      return TokError("unexpected token in '.org' directive");
+  }
+
+  Lex();
+
+  // FIXME: Only limited forms of relocatable expressions are accepted here, it
+  // has to be relative to the current section.
+  Out.EmitValueToOffset(Offset, FillExpr);
+
+  return false;
+}
+
+/// ParseDirectiveAlign
+///  ::= {.align, ...} expression [ , expression [ , expression ]]
+bool AsmParser::ParseDirectiveAlign(bool IsPow2, unsigned ValueSize) {
+  SMLoc AlignmentLoc = Lexer.getLoc();
+  int64_t Alignment;
+  if (ParseAbsoluteExpression(Alignment))
+    return true;
+
+  SMLoc MaxBytesLoc;
+  bool HasFillExpr = false;
+  int64_t FillExpr = 0;
+  int64_t MaxBytesToFill = 0;
+  if (Lexer.isNot(AsmToken::EndOfStatement)) {
+    if (Lexer.isNot(AsmToken::Comma))
+      return TokError("unexpected token in directive");
+    Lex();
+
+    // The fill expression can be omitted while specifying a maximum number of
+    // alignment bytes, e.g:
+    //  .align 3,,4
+    if (Lexer.isNot(AsmToken::Comma)) {
+      HasFillExpr = true;
+      if (ParseAbsoluteExpression(FillExpr))
+        return true;
+    }
+
+    if (Lexer.isNot(AsmToken::EndOfStatement)) {
+      if (Lexer.isNot(AsmToken::Comma))
+        return TokError("unexpected token in directive");
+      Lex();
+
+      MaxBytesLoc = Lexer.getLoc();
+      if (ParseAbsoluteExpression(MaxBytesToFill))
+        return true;
+      
+      if (Lexer.isNot(AsmToken::EndOfStatement))
+        return TokError("unexpected token in directive");
+    }
+  }
+
+  Lex();
+
+  if (!HasFillExpr) {
+    // FIXME: Sometimes fill with nop.
+    FillExpr = 0;
+  }
+
+  // Compute alignment in bytes.
+  if (IsPow2) {
+    // FIXME: Diagnose overflow.
+    if (Alignment >= 32) {
+      Error(AlignmentLoc, "invalid alignment value");
+      Alignment = 31;
+    }
+
+    Alignment = 1ULL << Alignment;
+  }
+
+  // Diagnose non-sensical max bytes to align.
+  if (MaxBytesLoc.isValid()) {
+    if (MaxBytesToFill < 1) {
+      Error(MaxBytesLoc, "alignment directive can never be satisfied in this "
+            "many bytes, ignoring maximum bytes expression");
+      MaxBytesToFill = 0;
+    }
+
+    if (MaxBytesToFill >= Alignment) {
+      Warning(MaxBytesLoc, "maximum bytes expression exceeds alignment and "
+              "has no effect");
+      MaxBytesToFill = 0;
+    }
+  }
+
+  // FIXME: Target specific behavior about how the "extra" bytes are filled.
+  Out.EmitValueToAlignment(Alignment, FillExpr, ValueSize, MaxBytesToFill);
+
+  return false;
+}
+
+/// ParseDirectiveSymbolAttribute
+///  ::= { ".globl", ".weak", ... } [ identifier ( , identifier )* ]
+bool AsmParser::ParseDirectiveSymbolAttribute(MCStreamer::SymbolAttr Attr) {
+  if (Lexer.isNot(AsmToken::EndOfStatement)) {
+    for (;;) {
+      StringRef Name;
+
+      if (ParseIdentifier(Name))
+        return TokError("expected identifier in directive");
+      
+      MCSymbol *Sym = CreateSymbol(Name);
+
+      Out.EmitSymbolAttribute(Sym, Attr);
+
+      if (Lexer.is(AsmToken::EndOfStatement))
+        break;
+
+      if (Lexer.isNot(AsmToken::Comma))
+        return TokError("unexpected token in directive");
+      Lex();
+    }
+  }
+
+  Lex();
+  return false;  
+}
+
+/// ParseDirectiveDarwinSymbolDesc
+///  ::= .desc identifier , expression
+bool AsmParser::ParseDirectiveDarwinSymbolDesc() {
+  StringRef Name;
+  if (ParseIdentifier(Name))
+    return TokError("expected identifier in directive");
+  
+  // Handle the identifier as the key symbol.
+  MCSymbol *Sym = CreateSymbol(Name);
+
+  if (Lexer.isNot(AsmToken::Comma))
+    return TokError("unexpected token in '.desc' directive");
+  Lex();
+
+  SMLoc DescLoc = Lexer.getLoc();
+  int64_t DescValue;
+  if (ParseAbsoluteExpression(DescValue))
+    return true;
+
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.desc' directive");
+  
+  Lex();
+
+  // Set the n_desc field of this Symbol to this DescValue
+  Out.EmitSymbolDesc(Sym, DescValue);
+
+  return false;
+}
+
+/// ParseDirectiveComm
+///  ::= ( .comm | .lcomm ) identifier , size_expression [ , align_expression ]
+bool AsmParser::ParseDirectiveComm(bool IsLocal) {
+  SMLoc IDLoc = Lexer.getLoc();
+  StringRef Name;
+  if (ParseIdentifier(Name))
+    return TokError("expected identifier in directive");
+  
+  // Handle the identifier as the key symbol.
+  MCSymbol *Sym = CreateSymbol(Name);
+
+  if (Lexer.isNot(AsmToken::Comma))
+    return TokError("unexpected token in directive");
+  Lex();
+
+  int64_t Size;
+  SMLoc SizeLoc = Lexer.getLoc();
+  if (ParseAbsoluteExpression(Size))
+    return true;
+
+  int64_t Pow2Alignment = 0;
+  SMLoc Pow2AlignmentLoc;
+  if (Lexer.is(AsmToken::Comma)) {
+    Lex();
+    Pow2AlignmentLoc = Lexer.getLoc();
+    if (ParseAbsoluteExpression(Pow2Alignment))
+      return true;
+    
+    // If this target takes alignments in bytes (not log) validate and convert.
+    if (Lexer.getMAI().getAlignmentIsInBytes()) {
+      if (!isPowerOf2_64(Pow2Alignment))
+        return Error(Pow2AlignmentLoc, "alignment must be a power of 2");
+      Pow2Alignment = Log2_64(Pow2Alignment);
+    }
+  }
+  
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.comm' or '.lcomm' directive");
+  
+  Lex();
+
+  // NOTE: a size of zero for a .comm should create a undefined symbol
+  // but a size of .lcomm creates a bss symbol of size zero.
+  if (Size < 0)
+    return Error(SizeLoc, "invalid '.comm' or '.lcomm' directive size, can't "
+                 "be less than zero");
+
+  // NOTE: The alignment in the directive is a power of 2 value, the assember
+  // may internally end up wanting an alignment in bytes.
+  // FIXME: Diagnose overflow.
+  if (Pow2Alignment < 0)
+    return Error(Pow2AlignmentLoc, "invalid '.comm' or '.lcomm' directive "
+                 "alignment, can't be less than zero");
+
+  if (!Sym->isUndefined())
+    return Error(IDLoc, "invalid symbol redefinition");
+
+  // '.lcomm' is equivalent to '.zerofill'.
+  // Create the Symbol as a common or local common with Size and Pow2Alignment
+  if (IsLocal) {
+    Out.EmitZerofill(getMachOSection("__DATA", "__bss",
+                                     MCSectionMachO::S_ZEROFILL, 0,
+                                     SectionKind()),
+                     Sym, Size, 1 << Pow2Alignment);
+    return false;
+  }
+
+  Out.EmitCommonSymbol(Sym, Size, 1 << Pow2Alignment);
+  return false;
+}
+
+/// ParseDirectiveDarwinZerofill
+///  ::= .zerofill segname , sectname [, identifier , size_expression [
+///      , align_expression ]]
+bool AsmParser::ParseDirectiveDarwinZerofill() {
+  // FIXME: Handle quoted names here.
+
+  if (Lexer.isNot(AsmToken::Identifier))
+    return TokError("expected segment name after '.zerofill' directive");
+  StringRef Segment = getTok().getString();
+  Lex();
+
+  if (Lexer.isNot(AsmToken::Comma))
+    return TokError("unexpected token in directive");
+  Lex();
+ 
+  if (Lexer.isNot(AsmToken::Identifier))
+    return TokError("expected section name after comma in '.zerofill' "
+                    "directive");
+  StringRef Section = getTok().getString();
+  Lex();
+
+  // If this is the end of the line all that was wanted was to create the
+  // the section but with no symbol.
+  if (Lexer.is(AsmToken::EndOfStatement)) {
+    // Create the zerofill section but no symbol
+    Out.EmitZerofill(getMachOSection(Segment, Section,
+                                     MCSectionMachO::S_ZEROFILL, 0,
+                                     SectionKind()));
+    return false;
+  }
+
+  if (Lexer.isNot(AsmToken::Comma))
+    return TokError("unexpected token in directive");
+  Lex();
+
+  if (Lexer.isNot(AsmToken::Identifier))
+    return TokError("expected identifier in directive");
+  
+  // handle the identifier as the key symbol.
+  SMLoc IDLoc = Lexer.getLoc();
+  MCSymbol *Sym = CreateSymbol(getTok().getString());
+  Lex();
+
+  if (Lexer.isNot(AsmToken::Comma))
+    return TokError("unexpected token in directive");
+  Lex();
+
+  int64_t Size;
+  SMLoc SizeLoc = Lexer.getLoc();
+  if (ParseAbsoluteExpression(Size))
+    return true;
+
+  int64_t Pow2Alignment = 0;
+  SMLoc Pow2AlignmentLoc;
+  if (Lexer.is(AsmToken::Comma)) {
+    Lex();
+    Pow2AlignmentLoc = Lexer.getLoc();
+    if (ParseAbsoluteExpression(Pow2Alignment))
+      return true;
+  }
+  
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.zerofill' directive");
+  
+  Lex();
+
+  if (Size < 0)
+    return Error(SizeLoc, "invalid '.zerofill' directive size, can't be less "
+                 "than zero");
+
+  // NOTE: The alignment in the directive is a power of 2 value, the assember
+  // may internally end up wanting an alignment in bytes.
+  // FIXME: Diagnose overflow.
+  if (Pow2Alignment < 0)
+    return Error(Pow2AlignmentLoc, "invalid '.zerofill' directive alignment, "
+                 "can't be less than zero");
+
+  if (!Sym->isUndefined())
+    return Error(IDLoc, "invalid symbol redefinition");
+
+  // Create the zerofill Symbol with Size and Pow2Alignment
+  //
+  // FIXME: Arch specific.
+  Out.EmitZerofill(getMachOSection(Segment, Section,
+                                 MCSectionMachO::S_ZEROFILL, 0,
+                                 SectionKind()),
+                   Sym, Size, 1 << Pow2Alignment);
+
+  return false;
+}
+
+/// ParseDirectiveDarwinSubsectionsViaSymbols
+///  ::= .subsections_via_symbols
+bool AsmParser::ParseDirectiveDarwinSubsectionsViaSymbols() {
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.subsections_via_symbols' directive");
+  
+  Lex();
+
+  Out.EmitAssemblerFlag(MCStreamer::SubsectionsViaSymbols);
+
+  return false;
+}
+
+/// ParseDirectiveAbort
+///  ::= .abort [ "abort_string" ]
+bool AsmParser::ParseDirectiveAbort() {
+  // FIXME: Use loc from directive.
+  SMLoc Loc = Lexer.getLoc();
+
+  StringRef Str = "";
+  if (Lexer.isNot(AsmToken::EndOfStatement)) {
+    if (Lexer.isNot(AsmToken::String))
+      return TokError("expected string in '.abort' directive");
+    
+    Str = getTok().getString();
+
+    Lex();
+  }
+
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.abort' directive");
+  
+  Lex();
+
+  // FIXME: Handle here.
+  if (Str.empty())
+    Error(Loc, ".abort detected. Assembly stopping.");
+  else
+    Error(Loc, ".abort '" + Str + "' detected. Assembly stopping.");
+
+  return false;
+}
+
+/// ParseDirectiveLsym
+///  ::= .lsym identifier , expression
+bool AsmParser::ParseDirectiveDarwinLsym() {
+  StringRef Name;
+  if (ParseIdentifier(Name))
+    return TokError("expected identifier in directive");
+  
+  // Handle the identifier as the key symbol.
+  MCSymbol *Sym = CreateSymbol(Name);
+
+  if (Lexer.isNot(AsmToken::Comma))
+    return TokError("unexpected token in '.lsym' directive");
+  Lex();
+
+  const MCExpr *Value;
+  SMLoc StartLoc = Lexer.getLoc();
+  if (ParseExpression(Value))
+    return true;
+
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.lsym' directive");
+  
+  Lex();
+
+  // We don't currently support this directive.
+  //
+  // FIXME: Diagnostic location!
+  (void) Sym;
+  return TokError("directive '.lsym' is unsupported");
+}
+
+/// ParseDirectiveInclude
+///  ::= .include "filename"
+bool AsmParser::ParseDirectiveInclude() {
+  if (Lexer.isNot(AsmToken::String))
+    return TokError("expected string in '.include' directive");
+  
+  std::string Filename = getTok().getString();
+  SMLoc IncludeLoc = Lexer.getLoc();
+  Lex();
+
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.include' directive");
+  
+  // Strip the quotes.
+  Filename = Filename.substr(1, Filename.size()-2);
+  
+  // Attempt to switch the lexer to the included file before consuming the end
+  // of statement to avoid losing it when we switch.
+  if (EnterIncludeFile(Filename)) {
+    PrintMessage(IncludeLoc,
+                 "Could not find include file '" + Filename + "'",
+                 "error");
+    return true;
+  }
+
+  return false;
+}
+
+/// ParseDirectiveDarwinDumpOrLoad
+///  ::= ( .dump | .load ) "filename"
+bool AsmParser::ParseDirectiveDarwinDumpOrLoad(SMLoc IDLoc, bool IsDump) {
+  if (Lexer.isNot(AsmToken::String))
+    return TokError("expected string in '.dump' or '.load' directive");
+  
+  Lex();
+
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.dump' or '.load' directive");
+  
+  Lex();
+
+  // FIXME: If/when .dump and .load are implemented they will be done in the
+  // the assembly parser and not have any need for an MCStreamer API.
+  if (IsDump)
+    Warning(IDLoc, "ignoring directive .dump for now");
+  else
+    Warning(IDLoc, "ignoring directive .load for now");
+
+  return false;
+}
+
+/// ParseDirectiveIf
+/// ::= .if expression
+bool AsmParser::ParseDirectiveIf(SMLoc DirectiveLoc) {
+  // Consume the identifier that was the .if directive
+  Lex();
+
+  TheCondStack.push_back(TheCondState);
+  TheCondState.TheCond = AsmCond::IfCond;
+  if(TheCondState.Ignore) {
+    EatToEndOfStatement();
+  }
+  else {
+    int64_t ExprValue;
+    if (ParseAbsoluteExpression(ExprValue))
+      return true;
+
+    if (Lexer.isNot(AsmToken::EndOfStatement))
+      return TokError("unexpected token in '.if' directive");
+    
+    Lex();
+
+    TheCondState.CondMet = ExprValue;
+    TheCondState.Ignore = !TheCondState.CondMet;
+  }
+
+  return false;
+}
+
+/// ParseDirectiveElseIf
+/// ::= .elseif expression
+bool AsmParser::ParseDirectiveElseIf(SMLoc DirectiveLoc) {
+  if (TheCondState.TheCond != AsmCond::IfCond &&
+      TheCondState.TheCond != AsmCond::ElseIfCond)
+      Error(DirectiveLoc, "Encountered a .elseif that doesn't follow a .if or "
+                          " an .elseif");
+  TheCondState.TheCond = AsmCond::ElseIfCond;
+
+  // Consume the identifier that was the .elseif directive
+  Lex();
+
+  bool LastIgnoreState = false;
+  if (!TheCondStack.empty())
+      LastIgnoreState = TheCondStack.back().Ignore;
+  if (LastIgnoreState || TheCondState.CondMet) {
+    TheCondState.Ignore = true;
+    EatToEndOfStatement();
+  }
+  else {
+    int64_t ExprValue;
+    if (ParseAbsoluteExpression(ExprValue))
+      return true;
+
+    if (Lexer.isNot(AsmToken::EndOfStatement))
+      return TokError("unexpected token in '.elseif' directive");
+    
+    Lex();
+    TheCondState.CondMet = ExprValue;
+    TheCondState.Ignore = !TheCondState.CondMet;
+  }
+
+  return false;
+}
+
+/// ParseDirectiveElse
+/// ::= .else
+bool AsmParser::ParseDirectiveElse(SMLoc DirectiveLoc) {
+  // Consume the identifier that was the .else directive
+  Lex();
+
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.else' directive");
+  
+  Lex();
+
+  if (TheCondState.TheCond != AsmCond::IfCond &&
+      TheCondState.TheCond != AsmCond::ElseIfCond)
+      Error(DirectiveLoc, "Encountered a .else that doesn't follow a .if or an "
+                          ".elseif");
+  TheCondState.TheCond = AsmCond::ElseCond;
+  bool LastIgnoreState = false;
+  if (!TheCondStack.empty())
+    LastIgnoreState = TheCondStack.back().Ignore;
+  if (LastIgnoreState || TheCondState.CondMet)
+    TheCondState.Ignore = true;
+  else
+    TheCondState.Ignore = false;
+
+  return false;
+}
+
+/// ParseDirectiveEndIf
+/// ::= .endif
+bool AsmParser::ParseDirectiveEndIf(SMLoc DirectiveLoc) {
+  // Consume the identifier that was the .endif directive
+  Lex();
+
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.endif' directive");
+  
+  Lex();
+
+  if ((TheCondState.TheCond == AsmCond::NoCond) ||
+      TheCondStack.empty())
+    Error(DirectiveLoc, "Encountered a .endif that doesn't follow a .if or "
+                        ".else");
+  if (!TheCondStack.empty()) {
+    TheCondState = TheCondStack.back();
+    TheCondStack.pop_back();
+  }
+
+  return false;
+}
+
+/// ParseDirectiveFile
+/// ::= .file [number] string
+bool AsmParser::ParseDirectiveFile(StringRef, SMLoc DirectiveLoc) {
+  // FIXME: I'm not sure what this is.
+  int64_t FileNumber = -1;
+  if (Lexer.is(AsmToken::Integer)) {
+    FileNumber = getTok().getIntVal();
+    Lex();
+    
+    if (FileNumber < 1)
+      return TokError("file number less than one");
+  }
+
+  if (Lexer.isNot(AsmToken::String))
+    return TokError("unexpected token in '.file' directive");
+  
+  StringRef ATTRIBUTE_UNUSED FileName = getTok().getString();
+  Lex();
+
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.file' directive");
+
+  // FIXME: Do something with the .file.
+
+  return false;
+}
+
+/// ParseDirectiveLine
+/// ::= .line [number]
+bool AsmParser::ParseDirectiveLine(StringRef, SMLoc DirectiveLoc) {
+  if (Lexer.isNot(AsmToken::EndOfStatement)) {
+    if (Lexer.isNot(AsmToken::Integer))
+      return TokError("unexpected token in '.line' directive");
+
+    int64_t LineNumber = getTok().getIntVal();
+    (void) LineNumber;
+    Lex();
+
+    // FIXME: Do something with the .line.
+  }
+
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.file' directive");
+
+  return false;
+}
+
+
+/// ParseDirectiveLoc
+/// ::= .loc number [number [number]]
+bool AsmParser::ParseDirectiveLoc(StringRef, SMLoc DirectiveLoc) {
+  if (Lexer.isNot(AsmToken::Integer))
+    return TokError("unexpected token in '.loc' directive");
+
+  // FIXME: What are these fields?
+  int64_t FileNumber = getTok().getIntVal();
+  (void) FileNumber;
+  // FIXME: Validate file.
+
+  Lex();
+  if (Lexer.isNot(AsmToken::EndOfStatement)) {
+    if (Lexer.isNot(AsmToken::Integer))
+      return TokError("unexpected token in '.loc' directive");
+
+    int64_t Param2 = getTok().getIntVal();
+    (void) Param2;
+    Lex();
+
+    if (Lexer.isNot(AsmToken::EndOfStatement)) {
+      if (Lexer.isNot(AsmToken::Integer))
+        return TokError("unexpected token in '.loc' directive");
+
+      int64_t Param3 = getTok().getIntVal();
+      (void) Param3;
+      Lex();
+
+      // FIXME: Do something with the .loc.
+    }
+  }
+
+  if (Lexer.isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.file' directive");
+
+  return false;
+}
+