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
diff --git a/lib/MC/MCParser/AsmLexer.cpp b/lib/MC/MCParser/AsmLexer.cpp
new file mode 100644
index 0000000..0b2e68c
--- /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.
+  }
+}