1 //===- AsmLexer.cpp - Lexer for Assembly Files ----------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This class implements the lexer for assembly files.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/MC/MCParser/AsmLexer.h"
15 #include "llvm/MC/MCAsmInfo.h"
16 #include "llvm/Support/MemoryBuffer.h"
17 #include "llvm/Support/SMLoc.h"
24 AsmLexer::AsmLexer(const MCAsmInfo &_MAI) : MAI(_MAI) {
27 isAtStartOfLine = true;
28 AllowAtInIdentifier = !StringRef(MAI.getCommentString()).startswith("@");
31 AsmLexer::~AsmLexer() {
34 void AsmLexer::setBuffer(const MemoryBuffer *buf, const char *ptr) {
40 CurPtr = CurBuf->getBufferStart();
45 /// ReturnError - Set the error to the specified string at the specified
46 /// location. This is defined to always return AsmToken::Error.
47 AsmToken AsmLexer::ReturnError(const char *Loc, const std::string &Msg) {
48 SetError(SMLoc::getFromPointer(Loc), Msg);
50 return AsmToken(AsmToken::Error, StringRef(Loc, 0));
53 int AsmLexer::getNextChar() {
54 char CurChar = *CurPtr++;
57 return (unsigned char)CurChar;
59 // A nul character in the stream is either the end of the current buffer or
60 // a random nul in the file. Disambiguate that here.
61 if (CurPtr-1 != CurBuf->getBufferEnd())
62 return 0; // Just whitespace.
64 // Otherwise, return end of file.
65 --CurPtr; // Another call to lex will return EOF again.
70 /// LexFloatLiteral: [0-9]*[.][0-9]*([eE][+-]?[0-9]*)?
72 /// The leading integral digit sequence and dot should have already been
73 /// consumed, some or all of the fractional digit sequence *can* have been
75 AsmToken AsmLexer::LexFloatLiteral() {
76 // Skip the fractional digit sequence.
77 while (isdigit(*CurPtr))
80 // Check for exponent; we intentionally accept a slighlty wider set of
81 // literals here and rely on the upstream client to reject invalid ones (e.g.,
83 if (*CurPtr == 'e' || *CurPtr == 'E') {
85 if (*CurPtr == '-' || *CurPtr == '+')
87 while (isdigit(*CurPtr))
91 return AsmToken(AsmToken::Real,
92 StringRef(TokStart, CurPtr - TokStart));
95 /// LexHexFloatLiteral matches essentially (.[0-9a-fA-F]*)?[pP][+-]?[0-9a-fA-F]+
96 /// while making sure there are enough actual digits around for the constant to
99 /// The leading "0x[0-9a-fA-F]*" (i.e. integer part) has already been consumed
100 /// before we get here.
101 AsmToken AsmLexer::LexHexFloatLiteral(bool NoIntDigits) {
102 assert((*CurPtr == 'p' || *CurPtr == 'P' || *CurPtr == '.') &&
103 "unexpected parse state in floating hex");
104 bool NoFracDigits = true;
106 // Skip the fractional part if there is one
107 if (*CurPtr == '.') {
110 const char *FracStart = CurPtr;
111 while (isxdigit(*CurPtr))
114 NoFracDigits = CurPtr == FracStart;
117 if (NoIntDigits && NoFracDigits)
118 return ReturnError(TokStart, "invalid hexadecimal floating-point constant: "
119 "expected at least one significand digit");
121 // Make sure we do have some kind of proper exponent part
122 if (*CurPtr != 'p' && *CurPtr != 'P')
123 return ReturnError(TokStart, "invalid hexadecimal floating-point constant: "
124 "expected exponent part 'p'");
127 if (*CurPtr == '+' || *CurPtr == '-')
130 // N.b. exponent digits are *not* hex
131 const char *ExpStart = CurPtr;
132 while (isdigit(*CurPtr))
135 if (CurPtr == ExpStart)
136 return ReturnError(TokStart, "invalid hexadecimal floating-point constant: "
137 "expected at least one exponent digit");
139 return AsmToken(AsmToken::Real, StringRef(TokStart, CurPtr - TokStart));
142 /// LexIdentifier: [a-zA-Z_.][a-zA-Z0-9_$.@?]*
143 static bool IsIdentifierChar(char c, bool AllowAt) {
144 return isalnum(c) || c == '_' || c == '$' || c == '.' ||
145 (c == '@' && AllowAt) || c == '?';
147 AsmToken AsmLexer::LexIdentifier() {
148 // Check for floating point literals.
149 if (CurPtr[-1] == '.' && isdigit(*CurPtr)) {
150 // Disambiguate a .1243foo identifier from a floating literal.
151 while (isdigit(*CurPtr))
153 if (*CurPtr == 'e' || *CurPtr == 'E' ||
154 !IsIdentifierChar(*CurPtr, AllowAtInIdentifier))
155 return LexFloatLiteral();
158 while (IsIdentifierChar(*CurPtr, AllowAtInIdentifier))
161 // Handle . as a special case.
162 if (CurPtr == TokStart+1 && TokStart[0] == '.')
163 return AsmToken(AsmToken::Dot, StringRef(TokStart, 1));
165 return AsmToken(AsmToken::Identifier, StringRef(TokStart, CurPtr - TokStart));
168 /// LexSlash: Slash: /
169 /// C-Style Comment: /* ... */
170 AsmToken AsmLexer::LexSlash() {
172 case '*': break; // C style comment.
173 case '/': return ++CurPtr, LexLineComment();
174 default: return AsmToken(AsmToken::Slash, StringRef(CurPtr-1, 1));
178 ++CurPtr; // skip the star.
180 int CurChar = getNextChar();
183 return ReturnError(TokStart, "unterminated comment");
185 // End of the comment?
186 if (CurPtr[0] != '/') break;
188 ++CurPtr; // End the */.
194 /// LexLineComment: Comment: #[^\n]*
196 AsmToken AsmLexer::LexLineComment() {
197 // FIXME: This is broken if we happen to a comment at the end of a file, which
198 // was .included, and which doesn't end with a newline.
199 int CurChar = getNextChar();
200 while (CurChar != '\n' && CurChar != '\r' && CurChar != EOF)
201 CurChar = getNextChar();
204 return AsmToken(AsmToken::Eof, StringRef(CurPtr, 0));
205 return AsmToken(AsmToken::EndOfStatement, StringRef(CurPtr, 0));
208 static void SkipIgnoredIntegerSuffix(const char *&CurPtr) {
209 // Skip ULL, UL, U, L and LL suffices.
210 if (CurPtr[0] == 'U')
212 if (CurPtr[0] == 'L')
214 if (CurPtr[0] == 'L')
218 // Look ahead to search for first non-hex digit, if it's [hH], then we treat the
219 // integer as a hexadecimal, possibly with leading zeroes.
220 static unsigned doLookAhead(const char *&CurPtr, unsigned DefaultRadix) {
221 const char *FirstHex = 0;
222 const char *LookAhead = CurPtr;
224 if (isdigit(*LookAhead)) {
226 } else if (isxdigit(*LookAhead)) {
228 FirstHex = LookAhead;
234 bool isHex = *LookAhead == 'h' || *LookAhead == 'H';
235 CurPtr = isHex || !FirstHex ? LookAhead : FirstHex;
241 /// LexDigit: First character is [0-9].
242 /// Local Label: [0-9][:]
243 /// Forward/Backward Label: [0-9][fb]
244 /// Binary integer: 0b[01]+
245 /// Octal integer: 0[0-7]+
246 /// Hex integer: 0x[0-9a-fA-F]+ or [0x]?[0-9][0-9a-fA-F]*[hH]
247 /// Decimal integer: [1-9][0-9]*
248 AsmToken AsmLexer::LexDigit() {
249 // Decimal integer: [1-9][0-9]*
250 if (CurPtr[-1] != '0' || CurPtr[0] == '.') {
251 unsigned Radix = doLookAhead(CurPtr, 10);
252 bool isHex = Radix == 16;
253 // Check for floating point literals.
254 if (!isHex && (*CurPtr == '.' || *CurPtr == 'e')) {
256 return LexFloatLiteral();
259 StringRef Result(TokStart, CurPtr - TokStart);
262 if (Result.getAsInteger(Radix, Value)) {
263 // Allow positive values that are too large to fit into a signed 64-bit
264 // integer, but that do fit in an unsigned one, we just convert them over.
265 unsigned long long UValue;
266 if (Result.getAsInteger(Radix, UValue))
267 return ReturnError(TokStart, !isHex ? "invalid decimal number" :
268 "invalid hexdecimal number");
269 Value = (long long)UValue;
272 // Consume the [bB][hH].
273 if (Radix == 2 || Radix == 16)
276 // The darwin/x86 (and x86-64) assembler accepts and ignores type
277 // suffices on integer literals.
278 SkipIgnoredIntegerSuffix(CurPtr);
280 return AsmToken(AsmToken::Integer, Result, Value);
283 if (*CurPtr == 'b') {
285 // See if we actually have "0b" as part of something like "jmp 0b\n"
286 if (!isdigit(CurPtr[0])) {
288 StringRef Result(TokStart, CurPtr - TokStart);
289 return AsmToken(AsmToken::Integer, Result, 0);
291 const char *NumStart = CurPtr;
292 while (CurPtr[0] == '0' || CurPtr[0] == '1')
295 // Requires at least one binary digit.
296 if (CurPtr == NumStart)
297 return ReturnError(TokStart, "invalid binary number");
299 StringRef Result(TokStart, CurPtr - TokStart);
302 if (Result.substr(2).getAsInteger(2, Value))
303 return ReturnError(TokStart, "invalid binary number");
305 // The darwin/x86 (and x86-64) assembler accepts and ignores ULL and LL
306 // suffixes on integer literals.
307 SkipIgnoredIntegerSuffix(CurPtr);
309 return AsmToken(AsmToken::Integer, Result, Value);
312 if (*CurPtr == 'x') {
314 const char *NumStart = CurPtr;
315 while (isxdigit(CurPtr[0]))
318 // "0x.0p0" is valid, and "0x0p0" (but not "0xp0" for example, which will be
319 // diagnosed by LexHexFloatLiteral).
320 if (CurPtr[0] == '.' || CurPtr[0] == 'p' || CurPtr[0] == 'P')
321 return LexHexFloatLiteral(NumStart == CurPtr);
323 // Otherwise requires at least one hex digit.
324 if (CurPtr == NumStart)
325 return ReturnError(CurPtr-2, "invalid hexadecimal number");
327 unsigned long long Result;
328 if (StringRef(TokStart, CurPtr - TokStart).getAsInteger(0, Result))
329 return ReturnError(TokStart, "invalid hexadecimal number");
331 // Consume the optional [hH].
332 if (*CurPtr == 'h' || *CurPtr == 'H')
335 // The darwin/x86 (and x86-64) assembler accepts and ignores ULL and LL
336 // suffixes on integer literals.
337 SkipIgnoredIntegerSuffix(CurPtr);
339 return AsmToken(AsmToken::Integer, StringRef(TokStart, CurPtr - TokStart),
343 // Either octal or hexadecimal.
345 unsigned Radix = doLookAhead(CurPtr, 8);
346 bool isHex = Radix == 16;
347 StringRef Result(TokStart, CurPtr - TokStart);
348 if (Result.getAsInteger(Radix, Value))
349 return ReturnError(TokStart, !isHex ? "invalid octal number" :
350 "invalid hexdecimal number");
356 // The darwin/x86 (and x86-64) assembler accepts and ignores ULL and LL
357 // suffixes on integer literals.
358 SkipIgnoredIntegerSuffix(CurPtr);
360 return AsmToken(AsmToken::Integer, Result, Value);
363 /// LexSingleQuote: Integer: 'b'
364 AsmToken AsmLexer::LexSingleQuote() {
365 int CurChar = getNextChar();
368 CurChar = getNextChar();
371 return ReturnError(TokStart, "unterminated single quote");
373 CurChar = getNextChar();
376 return ReturnError(TokStart, "single quote way too long");
378 // The idea here being that 'c' is basically just an integral
380 StringRef Res = StringRef(TokStart,CurPtr - TokStart);
383 if (Res.startswith("\'\\")) {
384 char theChar = Res[2];
386 default: Value = theChar; break;
387 case '\'': Value = '\''; break;
388 case 't': Value = '\t'; break;
389 case 'n': Value = '\n'; break;
390 case 'b': Value = '\b'; break;
395 return AsmToken(AsmToken::Integer, Res, Value);
399 /// LexQuote: String: "..."
400 AsmToken AsmLexer::LexQuote() {
401 int CurChar = getNextChar();
402 // TODO: does gas allow multiline string constants?
403 while (CurChar != '"') {
404 if (CurChar == '\\') {
406 CurChar = getNextChar();
410 return ReturnError(TokStart, "unterminated string constant");
412 CurChar = getNextChar();
415 return AsmToken(AsmToken::String, StringRef(TokStart, CurPtr - TokStart));
418 StringRef AsmLexer::LexUntilEndOfStatement() {
421 while (!isAtStartOfComment(*CurPtr) && // Start of line comment.
422 !isAtStatementSeparator(CurPtr) && // End of statement marker.
425 (*CurPtr != 0 || CurPtr != CurBuf->getBufferEnd())) {
428 return StringRef(TokStart, CurPtr-TokStart);
431 StringRef AsmLexer::LexUntilEndOfLine() {
434 while (*CurPtr != '\n' &&
436 (*CurPtr != 0 || CurPtr != CurBuf->getBufferEnd())) {
439 return StringRef(TokStart, CurPtr-TokStart);
442 bool AsmLexer::isAtStartOfComment(char Char) {
443 // FIXME: This won't work for multi-character comment indicators like "//".
444 return Char == *MAI.getCommentString();
447 bool AsmLexer::isAtStatementSeparator(const char *Ptr) {
448 return strncmp(Ptr, MAI.getSeparatorString(),
449 strlen(MAI.getSeparatorString())) == 0;
452 AsmToken AsmLexer::LexToken() {
454 // This always consumes at least one character.
455 int CurChar = getNextChar();
457 if (isAtStartOfComment(CurChar)) {
458 // If this comment starts with a '#', then return the Hash token and let
459 // the assembler parser see if it can be parsed as a cpp line filename
460 // comment. We do this only if we are at the start of a line.
461 if (CurChar == '#' && isAtStartOfLine)
462 return AsmToken(AsmToken::Hash, StringRef(TokStart, 1));
463 isAtStartOfLine = true;
464 return LexLineComment();
466 if (isAtStatementSeparator(TokStart)) {
467 CurPtr += strlen(MAI.getSeparatorString()) - 1;
468 return AsmToken(AsmToken::EndOfStatement,
469 StringRef(TokStart, strlen(MAI.getSeparatorString())));
472 // If we're missing a newline at EOF, make sure we still get an
473 // EndOfStatement token before the Eof token.
474 if (CurChar == EOF && !isAtStartOfLine) {
475 isAtStartOfLine = true;
476 return AsmToken(AsmToken::EndOfStatement, StringRef(TokStart, 1));
479 isAtStartOfLine = false;
482 // Handle identifier: [a-zA-Z_.][a-zA-Z0-9_$.@]*
483 if (isalpha(CurChar) || CurChar == '_' || CurChar == '.')
484 return LexIdentifier();
486 // Unknown character, emit an error.
487 return ReturnError(TokStart, "invalid character in input");
488 case EOF: return AsmToken(AsmToken::Eof, StringRef(TokStart, 0));
493 // Ignore whitespace.
497 while (*CurPtr==' ' || *CurPtr=='\t') {
501 return AsmToken(AsmToken::Space, StringRef(TokStart, len));
503 case '\n': // FALL THROUGH.
505 isAtStartOfLine = true;
506 return AsmToken(AsmToken::EndOfStatement, StringRef(TokStart, 1));
507 case ':': return AsmToken(AsmToken::Colon, StringRef(TokStart, 1));
508 case '+': return AsmToken(AsmToken::Plus, StringRef(TokStart, 1));
509 case '-': return AsmToken(AsmToken::Minus, StringRef(TokStart, 1));
510 case '~': return AsmToken(AsmToken::Tilde, StringRef(TokStart, 1));
511 case '(': return AsmToken(AsmToken::LParen, StringRef(TokStart, 1));
512 case ')': return AsmToken(AsmToken::RParen, StringRef(TokStart, 1));
513 case '[': return AsmToken(AsmToken::LBrac, StringRef(TokStart, 1));
514 case ']': return AsmToken(AsmToken::RBrac, StringRef(TokStart, 1));
515 case '{': return AsmToken(AsmToken::LCurly, StringRef(TokStart, 1));
516 case '}': return AsmToken(AsmToken::RCurly, StringRef(TokStart, 1));
517 case '*': return AsmToken(AsmToken::Star, StringRef(TokStart, 1));
518 case ',': return AsmToken(AsmToken::Comma, StringRef(TokStart, 1));
519 case '$': return AsmToken(AsmToken::Dollar, StringRef(TokStart, 1));
520 case '@': return AsmToken(AsmToken::At, StringRef(TokStart, 1));
521 case '\\': return AsmToken(AsmToken::BackSlash, StringRef(TokStart, 1));
524 return ++CurPtr, AsmToken(AsmToken::EqualEqual, StringRef(TokStart, 2));
525 return AsmToken(AsmToken::Equal, StringRef(TokStart, 1));
528 return ++CurPtr, AsmToken(AsmToken::PipePipe, StringRef(TokStart, 2));
529 return AsmToken(AsmToken::Pipe, StringRef(TokStart, 1));
530 case '^': return AsmToken(AsmToken::Caret, StringRef(TokStart, 1));
533 return ++CurPtr, AsmToken(AsmToken::AmpAmp, StringRef(TokStart, 2));
534 return AsmToken(AsmToken::Amp, StringRef(TokStart, 1));
537 return ++CurPtr, AsmToken(AsmToken::ExclaimEqual, StringRef(TokStart, 2));
538 return AsmToken(AsmToken::Exclaim, StringRef(TokStart, 1));
539 case '%': return AsmToken(AsmToken::Percent, StringRef(TokStart, 1));
540 case '/': return LexSlash();
541 case '#': return AsmToken(AsmToken::Hash, StringRef(TokStart, 1));
542 case '\'': return LexSingleQuote();
543 case '"': return LexQuote();
544 case '0': case '1': case '2': case '3': case '4':
545 case '5': case '6': case '7': case '8': case '9':
549 case '<': return ++CurPtr, AsmToken(AsmToken::LessLess,
550 StringRef(TokStart, 2));
551 case '=': return ++CurPtr, AsmToken(AsmToken::LessEqual,
552 StringRef(TokStart, 2));
553 case '>': return ++CurPtr, AsmToken(AsmToken::LessGreater,
554 StringRef(TokStart, 2));
555 default: return AsmToken(AsmToken::Less, StringRef(TokStart, 1));
559 case '>': return ++CurPtr, AsmToken(AsmToken::GreaterGreater,
560 StringRef(TokStart, 2));
561 case '=': return ++CurPtr, AsmToken(AsmToken::GreaterEqual,
562 StringRef(TokStart, 2));
563 default: return AsmToken(AsmToken::Greater, StringRef(TokStart, 1));
566 // TODO: Quoted identifiers (objc methods etc)
567 // local labels: [0-9][:]
568 // Forward/backward labels: [0-9][fb]
569 // Integers, fp constants, character constants.