TGLexer.cpp revision d04a8d4b33ff316ca4cf961e06c9e312eff8e64f 
1//===- TGLexer.cpp - Lexer for TableGen -----------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// Implement the Lexer for TableGen.
11//
12//===----------------------------------------------------------------------===//
13
14#include "TGLexer.h"
15#include "llvm/ADT/StringSwitch.h"
16#include "llvm/ADT/Twine.h"
17#include "llvm/Config/config.h" // for strtoull()/strtoll() define
18#include "llvm/Support/MemoryBuffer.h"
19#include "llvm/Support/SourceMgr.h"
20#include "llvm/TableGen/Error.h"
21#include <cctype>
22#include <cerrno>
23#include <cstdio>
24#include <cstdlib>
25#include <cstring>
26
27using namespace llvm;
28
29TGLexer::TGLexer(SourceMgr &SM) : SrcMgr(SM) {
30  CurBuffer = 0;
31  CurBuf = SrcMgr.getMemoryBuffer(CurBuffer);
32  CurPtr = CurBuf->getBufferStart();
33  TokStart = 0;
34}
35
36SMLoc TGLexer::getLoc() const {
37  return SMLoc::getFromPointer(TokStart);
38}
39
40/// ReturnError - Set the error to the specified string at the specified
41/// location.  This is defined to always return tgtok::Error.
42tgtok::TokKind TGLexer::ReturnError(const char *Loc, const Twine &Msg) {
43  PrintError(Loc, Msg);
44  return tgtok::Error;
45}
46
47int TGLexer::getNextChar() {
48  char CurChar = *CurPtr++;
49  switch (CurChar) {
50  default:
51    return (unsigned char)CurChar;
52  case 0: {
53    // A nul character in the stream is either the end of the current buffer or
54    // a random nul in the file.  Disambiguate that here.
55    if (CurPtr-1 != CurBuf->getBufferEnd())
56      return 0;  // Just whitespace.
57
58    // If this is the end of an included file, pop the parent file off the
59    // include stack.
60    SMLoc ParentIncludeLoc = SrcMgr.getParentIncludeLoc(CurBuffer);
61    if (ParentIncludeLoc != SMLoc()) {
62      CurBuffer = SrcMgr.FindBufferContainingLoc(ParentIncludeLoc);
63      CurBuf = SrcMgr.getMemoryBuffer(CurBuffer);
64      CurPtr = ParentIncludeLoc.getPointer();
65      return getNextChar();
66    }
67
68    // Otherwise, return end of file.
69    --CurPtr;  // Another call to lex will return EOF again.
70    return EOF;
71  }
72  case '\n':
73  case '\r':
74    // Handle the newline character by ignoring it and incrementing the line
75    // count.  However, be careful about 'dos style' files with \n\r in them.
76    // Only treat a \n\r or \r\n as a single line.
77    if ((*CurPtr == '\n' || (*CurPtr == '\r')) &&
78        *CurPtr != CurChar)
79      ++CurPtr;  // Eat the two char newline sequence.
80    return '\n';
81  }
82}
83
84int TGLexer::peekNextChar(int Index) {
85  return *(CurPtr + Index);
86}
87
88tgtok::TokKind TGLexer::LexToken() {
89  TokStart = CurPtr;
90  // This always consumes at least one character.
91  int CurChar = getNextChar();
92
93  switch (CurChar) {
94  default:
95    // Handle letters: [a-zA-Z_]
96    if (isalpha(CurChar) || CurChar == '_')
97      return LexIdentifier();
98
99    // Unknown character, emit an error.
100    return ReturnError(TokStart, "Unexpected character");
101  case EOF: return tgtok::Eof;
102  case ':': return tgtok::colon;
103  case ';': return tgtok::semi;
104  case '.': return tgtok::period;
105  case ',': return tgtok::comma;
106  case '<': return tgtok::less;
107  case '>': return tgtok::greater;
108  case ']': return tgtok::r_square;
109  case '{': return tgtok::l_brace;
110  case '}': return tgtok::r_brace;
111  case '(': return tgtok::l_paren;
112  case ')': return tgtok::r_paren;
113  case '=': return tgtok::equal;
114  case '?': return tgtok::question;
115  case '#': return tgtok::paste;
116
117  case 0:
118  case ' ':
119  case '\t':
120  case '\n':
121  case '\r':
122    // Ignore whitespace.
123    return LexToken();
124  case '/':
125    // If this is the start of a // comment, skip until the end of the line or
126    // the end of the buffer.
127    if (*CurPtr == '/')
128      SkipBCPLComment();
129    else if (*CurPtr == '*') {
130      if (SkipCComment())
131        return tgtok::Error;
132    } else // Otherwise, this is an error.
133      return ReturnError(TokStart, "Unexpected character");
134    return LexToken();
135  case '-': case '+':
136  case '0': case '1': case '2': case '3': case '4': case '5': case '6':
137  case '7': case '8': case '9': {
138    int NextChar = 0;
139    if (isdigit(CurChar)) {
140      // Allow identifiers to start with a number if it is followed by
141      // an identifier.  This can happen with paste operations like
142      // foo#8i.
143      int i = 0;
144      do {
145        NextChar = peekNextChar(i++);
146      } while (isdigit(NextChar));
147
148      if (NextChar == 'x' || NextChar == 'b') {
149        // If this is [0-9]b[01] or [0-9]x[0-9A-fa-f] this is most
150        // likely a number.
151        int NextNextChar = peekNextChar(i);
152        switch (NextNextChar) {
153        default:
154          break;
155        case '0': case '1':
156          if (NextChar == 'b')
157            return LexNumber();
158          // Fallthrough
159        case '2': case '3': case '4': case '5':
160        case '6': case '7': case '8': case '9':
161        case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
162        case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
163          if (NextChar == 'x')
164            return LexNumber();
165          break;
166        }
167      }
168    }
169
170    if (isalpha(NextChar) || NextChar == '_')
171      return LexIdentifier();
172
173    return LexNumber();
174  }
175  case '"': return LexString();
176  case '$': return LexVarName();
177  case '[': return LexBracket();
178  case '!': return LexExclaim();
179  }
180}
181
182/// LexString - Lex "[^"]*"
183tgtok::TokKind TGLexer::LexString() {
184  const char *StrStart = CurPtr;
185
186  CurStrVal = "";
187
188  while (*CurPtr != '"') {
189    // If we hit the end of the buffer, report an error.
190    if (*CurPtr == 0 && CurPtr == CurBuf->getBufferEnd())
191      return ReturnError(StrStart, "End of file in string literal");
192
193    if (*CurPtr == '\n' || *CurPtr == '\r')
194      return ReturnError(StrStart, "End of line in string literal");
195
196    if (*CurPtr != '\\') {
197      CurStrVal += *CurPtr++;
198      continue;
199    }
200
201    ++CurPtr;
202
203    switch (*CurPtr) {
204    case '\\': case '\'': case '"':
205      // These turn into their literal character.
206      CurStrVal += *CurPtr++;
207      break;
208    case 't':
209      CurStrVal += '\t';
210      ++CurPtr;
211      break;
212    case 'n':
213      CurStrVal += '\n';
214      ++CurPtr;
215      break;
216
217    case '\n':
218    case '\r':
219      return ReturnError(CurPtr, "escaped newlines not supported in tblgen");
220
221    // If we hit the end of the buffer, report an error.
222    case '\0':
223      if (CurPtr == CurBuf->getBufferEnd())
224        return ReturnError(StrStart, "End of file in string literal");
225      // FALL THROUGH
226    default:
227      return ReturnError(CurPtr, "invalid escape in string literal");
228    }
229  }
230
231  ++CurPtr;
232  return tgtok::StrVal;
233}
234
235tgtok::TokKind TGLexer::LexVarName() {
236  if (!isalpha(CurPtr[0]) && CurPtr[0] != '_')
237    return ReturnError(TokStart, "Invalid variable name");
238
239  // Otherwise, we're ok, consume the rest of the characters.
240  const char *VarNameStart = CurPtr++;
241
242  while (isalpha(*CurPtr) || isdigit(*CurPtr) || *CurPtr == '_')
243    ++CurPtr;
244
245  CurStrVal.assign(VarNameStart, CurPtr);
246  return tgtok::VarName;
247}
248
249
250tgtok::TokKind TGLexer::LexIdentifier() {
251  // The first letter is [a-zA-Z_#].
252  const char *IdentStart = TokStart;
253
254  // Match the rest of the identifier regex: [0-9a-zA-Z_#]*
255  while (isalpha(*CurPtr) || isdigit(*CurPtr) || *CurPtr == '_')
256    ++CurPtr;
257
258  // Check to see if this identifier is a keyword.
259  StringRef Str(IdentStart, CurPtr-IdentStart);
260
261  if (Str == "include") {
262    if (LexInclude()) return tgtok::Error;
263    return Lex();
264  }
265
266  tgtok::TokKind Kind = StringSwitch<tgtok::TokKind>(Str)
267    .Case("int", tgtok::Int)
268    .Case("bit", tgtok::Bit)
269    .Case("bits", tgtok::Bits)
270    .Case("string", tgtok::String)
271    .Case("list", tgtok::List)
272    .Case("code", tgtok::Code)
273    .Case("dag", tgtok::Dag)
274    .Case("class", tgtok::Class)
275    .Case("def", tgtok::Def)
276    .Case("foreach", tgtok::Foreach)
277    .Case("defm", tgtok::Defm)
278    .Case("multiclass", tgtok::MultiClass)
279    .Case("field", tgtok::Field)
280    .Case("let", tgtok::Let)
281    .Case("in", tgtok::In)
282    .Default(tgtok::Id);
283
284  if (Kind == tgtok::Id)
285    CurStrVal.assign(Str.begin(), Str.end());
286  return Kind;
287}
288
289/// LexInclude - We just read the "include" token.  Get the string token that
290/// comes next and enter the include.
291bool TGLexer::LexInclude() {
292  // The token after the include must be a string.
293  tgtok::TokKind Tok = LexToken();
294  if (Tok == tgtok::Error) return true;
295  if (Tok != tgtok::StrVal) {
296    PrintError(getLoc(), "Expected filename after include");
297    return true;
298  }
299
300  // Get the string.
301  std::string Filename = CurStrVal;
302  std::string IncludedFile;
303
304
305  CurBuffer = SrcMgr.AddIncludeFile(Filename, SMLoc::getFromPointer(CurPtr),
306                                    IncludedFile);
307  if (CurBuffer == -1) {
308    PrintError(getLoc(), "Could not find include file '" + Filename + "'");
309    return true;
310  }
311
312  Dependencies.push_back(IncludedFile);
313  // Save the line number and lex buffer of the includer.
314  CurBuf = SrcMgr.getMemoryBuffer(CurBuffer);
315  CurPtr = CurBuf->getBufferStart();
316  return false;
317}
318
319void TGLexer::SkipBCPLComment() {
320  ++CurPtr;  // skip the second slash.
321  while (1) {
322    switch (*CurPtr) {
323    case '\n':
324    case '\r':
325      return;  // Newline is end of comment.
326    case 0:
327      // If this is the end of the buffer, end the comment.
328      if (CurPtr == CurBuf->getBufferEnd())
329        return;
330      break;
331    }
332    // Otherwise, skip the character.
333    ++CurPtr;
334  }
335}
336
337/// SkipCComment - This skips C-style /**/ comments.  The only difference from C
338/// is that we allow nesting.
339bool TGLexer::SkipCComment() {
340  ++CurPtr;  // skip the star.
341  unsigned CommentDepth = 1;
342
343  while (1) {
344    int CurChar = getNextChar();
345    switch (CurChar) {
346    case EOF:
347      PrintError(TokStart, "Unterminated comment!");
348      return true;
349    case '*':
350      // End of the comment?
351      if (CurPtr[0] != '/') break;
352
353      ++CurPtr;   // End the */.
354      if (--CommentDepth == 0)
355        return false;
356      break;
357    case '/':
358      // Start of a nested comment?
359      if (CurPtr[0] != '*') break;
360      ++CurPtr;
361      ++CommentDepth;
362      break;
363    }
364  }
365}
366
367/// LexNumber - Lex:
368///    [-+]?[0-9]+
369///    0x[0-9a-fA-F]+
370///    0b[01]+
371tgtok::TokKind TGLexer::LexNumber() {
372  if (CurPtr[-1] == '0') {
373    if (CurPtr[0] == 'x') {
374      ++CurPtr;
375      const char *NumStart = CurPtr;
376      while (isxdigit(CurPtr[0]))
377        ++CurPtr;
378
379      // Requires at least one hex digit.
380      if (CurPtr == NumStart)
381        return ReturnError(TokStart, "Invalid hexadecimal number");
382
383      errno = 0;
384      CurIntVal = strtoll(NumStart, 0, 16);
385      if (errno == EINVAL)
386        return ReturnError(TokStart, "Invalid hexadecimal number");
387      if (errno == ERANGE) {
388        errno = 0;
389        CurIntVal = (int64_t)strtoull(NumStart, 0, 16);
390        if (errno == EINVAL)
391          return ReturnError(TokStart, "Invalid hexadecimal number");
392        if (errno == ERANGE)
393          return ReturnError(TokStart, "Hexadecimal number out of range");
394      }
395      return tgtok::IntVal;
396    } else if (CurPtr[0] == 'b') {
397      ++CurPtr;
398      const char *NumStart = CurPtr;
399      while (CurPtr[0] == '0' || CurPtr[0] == '1')
400        ++CurPtr;
401
402      // Requires at least one binary digit.
403      if (CurPtr == NumStart)
404        return ReturnError(CurPtr-2, "Invalid binary number");
405      CurIntVal = strtoll(NumStart, 0, 2);
406      return tgtok::IntVal;
407    }
408  }
409
410  // Check for a sign without a digit.
411  if (!isdigit(CurPtr[0])) {
412    if (CurPtr[-1] == '-')
413      return tgtok::minus;
414    else if (CurPtr[-1] == '+')
415      return tgtok::plus;
416  }
417
418  while (isdigit(CurPtr[0]))
419    ++CurPtr;
420  CurIntVal = strtoll(TokStart, 0, 10);
421  return tgtok::IntVal;
422}
423
424/// LexBracket - We just read '['.  If this is a code block, return it,
425/// otherwise return the bracket.  Match: '[' and '[{ ( [^}]+ | }[^]] )* }]'
426tgtok::TokKind TGLexer::LexBracket() {
427  if (CurPtr[0] != '{')
428    return tgtok::l_square;
429  ++CurPtr;
430  const char *CodeStart = CurPtr;
431  while (1) {
432    int Char = getNextChar();
433    if (Char == EOF) break;
434
435    if (Char != '}') continue;
436
437    Char = getNextChar();
438    if (Char == EOF) break;
439    if (Char == ']') {
440      CurStrVal.assign(CodeStart, CurPtr-2);
441      return tgtok::CodeFragment;
442    }
443  }
444
445  return ReturnError(CodeStart-2, "Unterminated Code Block");
446}
447
448/// LexExclaim - Lex '!' and '![a-zA-Z]+'.
449tgtok::TokKind TGLexer::LexExclaim() {
450  if (!isalpha(*CurPtr))
451    return ReturnError(CurPtr - 1, "Invalid \"!operator\"");
452
453  const char *Start = CurPtr++;
454  while (isalpha(*CurPtr))
455    ++CurPtr;
456
457  // Check to see which operator this is.
458  tgtok::TokKind Kind =
459    StringSwitch<tgtok::TokKind>(StringRef(Start, CurPtr - Start))
460    .Case("eq", tgtok::XEq)
461    .Case("if", tgtok::XIf)
462    .Case("head", tgtok::XHead)
463    .Case("tail", tgtok::XTail)
464    .Case("con", tgtok::XConcat)
465    .Case("shl", tgtok::XSHL)
466    .Case("sra", tgtok::XSRA)
467    .Case("srl", tgtok::XSRL)
468    .Case("cast", tgtok::XCast)
469    .Case("empty", tgtok::XEmpty)
470    .Case("subst", tgtok::XSubst)
471    .Case("foreach", tgtok::XForEach)
472    .Case("strconcat", tgtok::XStrConcat)
473    .Default(tgtok::Error);
474
475  return Kind != tgtok::Error ? Kind : ReturnError(Start-1, "Unknown operator");
476}
477
478