LiteralSupport.cpp revision 4984212fced6d9c6538ebb7319839105e3880b45 
1//===--- LiteralSupport.cpp - Code to parse and process literals ----------===//
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// This file implements the NumericLiteralParser, CharLiteralParser, and
11// StringLiteralParser interfaces.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/Lex/LiteralSupport.h"
16#include "clang/Lex/Preprocessor.h"
17#include "clang/Basic/Diagnostic.h"
18#include "clang/Basic/TargetInfo.h"
19#include "llvm/ADT/StringExtras.h"
20using namespace clang;
21
22/// HexDigitValue - Return the value of the specified hex digit, or -1 if it's
23/// not valid.
24static int HexDigitValue(char C) {
25  if (C >= '0' && C <= '9') return C-'0';
26  if (C >= 'a' && C <= 'f') return C-'a'+10;
27  if (C >= 'A' && C <= 'F') return C-'A'+10;
28  return -1;
29}
30
31/// ProcessCharEscape - Parse a standard C escape sequence, which can occur in
32/// either a character or a string literal.
33static unsigned ProcessCharEscape(const char *&ThisTokBuf,
34                                  const char *ThisTokEnd, bool &HadError,
35                                  SourceLocation Loc, bool IsWide,
36                                  Preprocessor &PP) {
37  // Skip the '\' char.
38  ++ThisTokBuf;
39
40  // We know that this character can't be off the end of the buffer, because
41  // that would have been \", which would not have been the end of string.
42  unsigned ResultChar = *ThisTokBuf++;
43  switch (ResultChar) {
44  // These map to themselves.
45  case '\\': case '\'': case '"': case '?': break;
46
47    // These have fixed mappings.
48  case 'a':
49    // TODO: K&R: the meaning of '\\a' is different in traditional C
50    ResultChar = 7;
51    break;
52  case 'b':
53    ResultChar = 8;
54    break;
55  case 'e':
56    PP.Diag(Loc, diag::ext_nonstandard_escape) << "e";
57    ResultChar = 27;
58    break;
59  case 'f':
60    ResultChar = 12;
61    break;
62  case 'n':
63    ResultChar = 10;
64    break;
65  case 'r':
66    ResultChar = 13;
67    break;
68  case 't':
69    ResultChar = 9;
70    break;
71  case 'v':
72    ResultChar = 11;
73    break;
74
75    //case 'u': case 'U':  // FIXME: UCNs.
76  case 'x': { // Hex escape.
77    ResultChar = 0;
78    if (ThisTokBuf == ThisTokEnd || !isxdigit(*ThisTokBuf)) {
79      PP.Diag(Loc, diag::err_hex_escape_no_digits);
80      HadError = 1;
81      break;
82    }
83
84    // Hex escapes are a maximal series of hex digits.
85    bool Overflow = false;
86    for (; ThisTokBuf != ThisTokEnd; ++ThisTokBuf) {
87      int CharVal = HexDigitValue(ThisTokBuf[0]);
88      if (CharVal == -1) break;
89      // About to shift out a digit?
90      Overflow |= (ResultChar & 0xF0000000) ? true : false;
91      ResultChar <<= 4;
92      ResultChar |= CharVal;
93    }
94
95    // See if any bits will be truncated when evaluated as a character.
96    unsigned CharWidth = PP.getTargetInfo().getCharWidth(IsWide);
97
98    if (CharWidth != 32 && (ResultChar >> CharWidth) != 0) {
99      Overflow = true;
100      ResultChar &= ~0U >> (32-CharWidth);
101    }
102
103    // Check for overflow.
104    if (Overflow)   // Too many digits to fit in
105      PP.Diag(Loc, diag::warn_hex_escape_too_large);
106    break;
107  }
108  case '0': case '1': case '2': case '3':
109  case '4': case '5': case '6': case '7': {
110    // Octal escapes.
111    --ThisTokBuf;
112    ResultChar = 0;
113
114    // Octal escapes are a series of octal digits with maximum length 3.
115    // "\0123" is a two digit sequence equal to "\012" "3".
116    unsigned NumDigits = 0;
117    do {
118      ResultChar <<= 3;
119      ResultChar |= *ThisTokBuf++ - '0';
120      ++NumDigits;
121    } while (ThisTokBuf != ThisTokEnd && NumDigits < 3 &&
122             ThisTokBuf[0] >= '0' && ThisTokBuf[0] <= '7');
123
124    // Check for overflow.  Reject '\777', but not L'\777'.
125    unsigned CharWidth = PP.getTargetInfo().getCharWidth(IsWide);
126
127    if (CharWidth != 32 && (ResultChar >> CharWidth) != 0) {
128      PP.Diag(Loc, diag::warn_octal_escape_too_large);
129      ResultChar &= ~0U >> (32-CharWidth);
130    }
131    break;
132  }
133
134    // Otherwise, these are not valid escapes.
135  case '(': case '{': case '[': case '%':
136    // GCC accepts these as extensions.  We warn about them as such though.
137    if (!PP.getLangOptions().NoExtensions) {
138      PP.Diag(Loc, diag::ext_nonstandard_escape)
139        << std::string()+(char)ResultChar;
140      break;
141    }
142    // FALL THROUGH.
143  default:
144    if (isgraph(ThisTokBuf[0]))
145      PP.Diag(Loc, diag::ext_unknown_escape) << std::string()+(char)ResultChar;
146    else
147      PP.Diag(Loc, diag::ext_unknown_escape) << "x"+llvm::utohexstr(ResultChar);
148    break;
149  }
150
151  return ResultChar;
152}
153
154
155
156
157///       integer-constant: [C99 6.4.4.1]
158///         decimal-constant integer-suffix
159///         octal-constant integer-suffix
160///         hexadecimal-constant integer-suffix
161///       decimal-constant:
162///         nonzero-digit
163///         decimal-constant digit
164///       octal-constant:
165///         0
166///         octal-constant octal-digit
167///       hexadecimal-constant:
168///         hexadecimal-prefix hexadecimal-digit
169///         hexadecimal-constant hexadecimal-digit
170///       hexadecimal-prefix: one of
171///         0x 0X
172///       integer-suffix:
173///         unsigned-suffix [long-suffix]
174///         unsigned-suffix [long-long-suffix]
175///         long-suffix [unsigned-suffix]
176///         long-long-suffix [unsigned-sufix]
177///       nonzero-digit:
178///         1 2 3 4 5 6 7 8 9
179///       octal-digit:
180///         0 1 2 3 4 5 6 7
181///       hexadecimal-digit:
182///         0 1 2 3 4 5 6 7 8 9
183///         a b c d e f
184///         A B C D E F
185///       unsigned-suffix: one of
186///         u U
187///       long-suffix: one of
188///         l L
189///       long-long-suffix: one of
190///         ll LL
191///
192///       floating-constant: [C99 6.4.4.2]
193///         TODO: add rules...
194///
195NumericLiteralParser::
196NumericLiteralParser(const char *begin, const char *end,
197                     SourceLocation TokLoc, Preprocessor &pp)
198  : PP(pp), ThisTokBegin(begin), ThisTokEnd(end) {
199
200  // This routine assumes that the range begin/end matches the regex for integer
201  // and FP constants (specifically, the 'pp-number' regex), and assumes that
202  // the byte at "*end" is both valid and not part of the regex.  Because of
203  // this, it doesn't have to check for 'overscan' in various places.
204  assert(!isalnum(*end) && *end != '.' && *end != '_' &&
205         "Lexer didn't maximally munch?");
206
207  s = DigitsBegin = begin;
208  saw_exponent = false;
209  saw_period = false;
210  isLong = false;
211  isUnsigned = false;
212  isLongLong = false;
213  isFloat = false;
214  isImaginary = false;
215  hadError = false;
216
217  if (*s == '0') { // parse radix
218    ParseNumberStartingWithZero(TokLoc);
219    if (hadError)
220      return;
221  } else { // the first digit is non-zero
222    radix = 10;
223    s = SkipDigits(s);
224    if (s == ThisTokEnd) {
225      // Done.
226    } else if (isxdigit(*s) && !(*s == 'e' || *s == 'E')) {
227      PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-begin),
228              diag::err_invalid_decimal_digit) << std::string(s, s+1);
229      hadError = true;
230      return;
231    } else if (*s == '.') {
232      s++;
233      saw_period = true;
234      s = SkipDigits(s);
235    }
236    if ((*s == 'e' || *s == 'E')) { // exponent
237      const char *Exponent = s;
238      s++;
239      saw_exponent = true;
240      if (*s == '+' || *s == '-')  s++; // sign
241      const char *first_non_digit = SkipDigits(s);
242      if (first_non_digit != s) {
243        s = first_non_digit;
244      } else {
245        PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Exponent-begin),
246                diag::err_exponent_has_no_digits);
247        hadError = true;
248        return;
249      }
250    }
251  }
252
253  SuffixBegin = s;
254
255  // Parse the suffix.  At this point we can classify whether we have an FP or
256  // integer constant.
257  bool isFPConstant = isFloatingLiteral();
258
259  // Loop over all of the characters of the suffix.  If we see something bad,
260  // we break out of the loop.
261  for (; s != ThisTokEnd; ++s) {
262    switch (*s) {
263    case 'f':      // FP Suffix for "float"
264    case 'F':
265      if (!isFPConstant) break;  // Error for integer constant.
266      if (isFloat || isLong) break; // FF, LF invalid.
267      isFloat = true;
268      continue;  // Success.
269    case 'u':
270    case 'U':
271      if (isFPConstant) break;  // Error for floating constant.
272      if (isUnsigned) break;    // Cannot be repeated.
273      isUnsigned = true;
274      continue;  // Success.
275    case 'l':
276    case 'L':
277      if (isLong || isLongLong) break;  // Cannot be repeated.
278      if (isFloat) break;               // LF invalid.
279
280      // Check for long long.  The L's need to be adjacent and the same case.
281      if (s+1 != ThisTokEnd && s[1] == s[0]) {
282        if (isFPConstant) break;        // long long invalid for floats.
283        isLongLong = true;
284        ++s;  // Eat both of them.
285      } else {
286        isLong = true;
287      }
288      continue;  // Success.
289    case 'i':
290      if (PP.getLangOptions().Microsoft) {
291        // Allow i8, i16, i32, i64, and i128.
292        if (++s == ThisTokEnd) break;
293        switch (*s) {
294          case '8':
295            s++; // i8 suffix
296            break;
297          case '1':
298            if (++s == ThisTokEnd) break;
299            if (*s == '6') s++; // i16 suffix
300            else if (*s == '2') {
301              if (++s == ThisTokEnd) break;
302              if (*s == '8') s++; // i128 suffix
303            }
304            break;
305          case '3':
306            if (++s == ThisTokEnd) break;
307            if (*s == '2') s++; // i32 suffix
308            break;
309          case '6':
310            if (++s == ThisTokEnd) break;
311            if (*s == '4') s++; // i64 suffix
312            break;
313          default:
314            break;
315        }
316        break;
317      }
318      // fall through.
319    case 'I':
320    case 'j':
321    case 'J':
322      if (isImaginary) break;   // Cannot be repeated.
323      PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-begin),
324              diag::ext_imaginary_constant);
325      isImaginary = true;
326      continue;  // Success.
327    }
328    // If we reached here, there was an error.
329    break;
330  }
331
332  // Report an error if there are any.
333  if (s != ThisTokEnd) {
334    PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-begin),
335            isFPConstant ? diag::err_invalid_suffix_float_constant :
336                           diag::err_invalid_suffix_integer_constant)
337      << std::string(SuffixBegin, ThisTokEnd);
338    hadError = true;
339    return;
340  }
341}
342
343/// ParseNumberStartingWithZero - This method is called when the first character
344/// of the number is found to be a zero.  This means it is either an octal
345/// number (like '04') or a hex number ('0x123a') a binary number ('0b1010') or
346/// a floating point number (01239.123e4).  Eat the prefix, determining the
347/// radix etc.
348void NumericLiteralParser::ParseNumberStartingWithZero(SourceLocation TokLoc) {
349  assert(s[0] == '0' && "Invalid method call");
350  s++;
351
352  // Handle a hex number like 0x1234.
353  if ((*s == 'x' || *s == 'X') && (isxdigit(s[1]) || s[1] == '.')) {
354    s++;
355    radix = 16;
356    DigitsBegin = s;
357    s = SkipHexDigits(s);
358    if (s == ThisTokEnd) {
359      // Done.
360    } else if (*s == '.') {
361      s++;
362      saw_period = true;
363      s = SkipHexDigits(s);
364    }
365    // A binary exponent can appear with or with a '.'. If dotted, the
366    // binary exponent is required.
367    if (*s == 'p' || *s == 'P') {
368      const char *Exponent = s;
369      s++;
370      saw_exponent = true;
371      if (*s == '+' || *s == '-')  s++; // sign
372      const char *first_non_digit = SkipDigits(s);
373      if (first_non_digit == s) {
374        PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Exponent-ThisTokBegin),
375                diag::err_exponent_has_no_digits);
376        hadError = true;
377        return;
378      }
379      s = first_non_digit;
380
381      if (!PP.getLangOptions().HexFloats)
382        PP.Diag(TokLoc, diag::ext_hexconstant_invalid);
383    } else if (saw_period) {
384      PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin),
385              diag::err_hexconstant_requires_exponent);
386      hadError = true;
387    }
388    return;
389  }
390
391  // Handle simple binary numbers 0b01010
392  if (*s == 'b' || *s == 'B') {
393    // 0b101010 is a GCC extension.
394    PP.Diag(TokLoc, diag::ext_binary_literal);
395    ++s;
396    radix = 2;
397    DigitsBegin = s;
398    s = SkipBinaryDigits(s);
399    if (s == ThisTokEnd) {
400      // Done.
401    } else if (isxdigit(*s)) {
402      PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin),
403              diag::err_invalid_binary_digit) << std::string(s, s+1);
404      hadError = true;
405    }
406    // Other suffixes will be diagnosed by the caller.
407    return;
408  }
409
410  // For now, the radix is set to 8. If we discover that we have a
411  // floating point constant, the radix will change to 10. Octal floating
412  // point constants are not permitted (only decimal and hexadecimal).
413  radix = 8;
414  DigitsBegin = s;
415  s = SkipOctalDigits(s);
416  if (s == ThisTokEnd)
417    return; // Done, simple octal number like 01234
418
419  // If we have some other non-octal digit that *is* a decimal digit, see if
420  // this is part of a floating point number like 094.123 or 09e1.
421  if (isdigit(*s)) {
422    const char *EndDecimal = SkipDigits(s);
423    if (EndDecimal[0] == '.' || EndDecimal[0] == 'e' || EndDecimal[0] == 'E') {
424      s = EndDecimal;
425      radix = 10;
426    }
427  }
428
429  // If we have a hex digit other than 'e' (which denotes a FP exponent) then
430  // the code is using an incorrect base.
431  if (isxdigit(*s) && *s != 'e' && *s != 'E') {
432    PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin),
433            diag::err_invalid_octal_digit) << std::string(s, s+1);
434    hadError = true;
435    return;
436  }
437
438  if (*s == '.') {
439    s++;
440    radix = 10;
441    saw_period = true;
442    s = SkipDigits(s); // Skip suffix.
443  }
444  if (*s == 'e' || *s == 'E') { // exponent
445    const char *Exponent = s;
446    s++;
447    radix = 10;
448    saw_exponent = true;
449    if (*s == '+' || *s == '-')  s++; // sign
450    const char *first_non_digit = SkipDigits(s);
451    if (first_non_digit != s) {
452      s = first_non_digit;
453    } else {
454      PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Exponent-ThisTokBegin),
455              diag::err_exponent_has_no_digits);
456      hadError = true;
457      return;
458    }
459  }
460}
461
462
463/// GetIntegerValue - Convert this numeric literal value to an APInt that
464/// matches Val's input width.  If there is an overflow, set Val to the low bits
465/// of the result and return true.  Otherwise, return false.
466bool NumericLiteralParser::GetIntegerValue(llvm::APInt &Val) {
467  // Fast path: Compute a conservative bound on the maximum number of
468  // bits per digit in this radix. If we can't possibly overflow a
469  // uint64 based on that bound then do the simple conversion to
470  // integer. This avoids the expensive overflow checking below, and
471  // handles the common cases that matter (small decimal integers and
472  // hex/octal values which don't overflow).
473  unsigned MaxBitsPerDigit = 1;
474  while ((1U << MaxBitsPerDigit) < radix)
475    MaxBitsPerDigit += 1;
476  if ((SuffixBegin - DigitsBegin) * MaxBitsPerDigit <= 64) {
477    uint64_t N = 0;
478    for (s = DigitsBegin; s != SuffixBegin; ++s)
479      N = N*radix + HexDigitValue(*s);
480
481    // This will truncate the value to Val's input width. Simply check
482    // for overflow by comparing.
483    Val = N;
484    return Val.getZExtValue() != N;
485  }
486
487  Val = 0;
488  s = DigitsBegin;
489
490  llvm::APInt RadixVal(Val.getBitWidth(), radix);
491  llvm::APInt CharVal(Val.getBitWidth(), 0);
492  llvm::APInt OldVal = Val;
493
494  bool OverflowOccurred = false;
495  while (s < SuffixBegin) {
496    unsigned C = HexDigitValue(*s++);
497
498    // If this letter is out of bound for this radix, reject it.
499    assert(C < radix && "NumericLiteralParser ctor should have rejected this");
500
501    CharVal = C;
502
503    // Add the digit to the value in the appropriate radix.  If adding in digits
504    // made the value smaller, then this overflowed.
505    OldVal = Val;
506
507    // Multiply by radix, did overflow occur on the multiply?
508    Val *= RadixVal;
509    OverflowOccurred |= Val.udiv(RadixVal) != OldVal;
510
511    // Add value, did overflow occur on the value?
512    //   (a + b) ult b  <=> overflow
513    Val += CharVal;
514    OverflowOccurred |= Val.ult(CharVal);
515  }
516  return OverflowOccurred;
517}
518
519llvm::APFloat NumericLiteralParser::
520GetFloatValue(const llvm::fltSemantics &Format, bool* isExact) {
521  using llvm::APFloat;
522
523  llvm::SmallVector<char,256> floatChars;
524  for (unsigned i = 0, n = ThisTokEnd-ThisTokBegin; i != n; ++i)
525    floatChars.push_back(ThisTokBegin[i]);
526
527  floatChars.push_back('\0');
528
529  APFloat V (Format, APFloat::fcZero, false);
530  APFloat::opStatus status;
531
532  status = V.convertFromString(&floatChars[0],APFloat::rmNearestTiesToEven);
533
534  if (isExact)
535    *isExact = status == APFloat::opOK;
536
537  return V;
538}
539
540
541CharLiteralParser::CharLiteralParser(const char *begin, const char *end,
542                                     SourceLocation Loc, Preprocessor &PP) {
543  // At this point we know that the character matches the regex "L?'.*'".
544  HadError = false;
545  Value = 0;
546
547  // Determine if this is a wide character.
548  IsWide = begin[0] == 'L';
549  if (IsWide) ++begin;
550
551  // Skip over the entry quote.
552  assert(begin[0] == '\'' && "Invalid token lexed");
553  ++begin;
554
555  // FIXME: This assumes that 'int' is 32-bits in overflow calculation, and the
556  // size of "value".
557  assert(PP.getTargetInfo().getIntWidth() == 32 &&
558         "Assumes sizeof(int) == 4 for now");
559  // FIXME: This assumes that wchar_t is 32-bits for now.
560  assert(PP.getTargetInfo().getWCharWidth() == 32 &&
561         "Assumes sizeof(wchar_t) == 4 for now");
562  // FIXME: This extensively assumes that 'char' is 8-bits.
563  assert(PP.getTargetInfo().getCharWidth() == 8 &&
564         "Assumes char is 8 bits");
565
566  bool isFirstChar = true;
567  bool isMultiChar = false;
568  while (begin[0] != '\'') {
569    unsigned ResultChar;
570    if (begin[0] != '\\')     // If this is a normal character, consume it.
571      ResultChar = *begin++;
572    else                      // Otherwise, this is an escape character.
573      ResultChar = ProcessCharEscape(begin, end, HadError, Loc, IsWide, PP);
574
575    // If this is a multi-character constant (e.g. 'abc'), handle it.  These are
576    // implementation defined (C99 6.4.4.4p10).
577    if (!isFirstChar) {
578      // If this is the second character being processed, do special handling.
579      if (!isMultiChar) {
580        isMultiChar = true;
581
582        // Warn about discarding the top bits for multi-char wide-character
583        // constants (L'abcd').
584        if (IsWide)
585          PP.Diag(Loc, diag::warn_extraneous_wide_char_constant);
586      }
587
588      if (IsWide) {
589        // Emulate GCC's (unintentional?) behavior: L'ab' -> L'b'.
590        Value = 0;
591      } else {
592        // Narrow character literals act as though their value is concatenated
593        // in this implementation.
594        if (((Value << 8) >> 8) != Value)
595          PP.Diag(Loc, diag::warn_char_constant_too_large);
596        Value <<= 8;
597      }
598    }
599
600    Value += ResultChar;
601    isFirstChar = false;
602  }
603
604  // If this is a single narrow character, sign extend it (e.g. '\xFF' is "-1")
605  // if 'char' is signed for this target (C99 6.4.4.4p10).  Note that multiple
606  // character constants are not sign extended in the this implementation:
607  // '\xFF\xFF' = 65536 and '\x0\xFF' = 255, which matches GCC.
608  if (!IsWide && !isMultiChar && (Value & 128) &&
609      PP.getTargetInfo().isCharSigned())
610    Value = (signed char)Value;
611}
612
613
614///       string-literal: [C99 6.4.5]
615///          " [s-char-sequence] "
616///         L" [s-char-sequence] "
617///       s-char-sequence:
618///         s-char
619///         s-char-sequence s-char
620///       s-char:
621///         any source character except the double quote ",
622///           backslash \, or newline character
623///         escape-character
624///         universal-character-name
625///       escape-character: [C99 6.4.4.4]
626///         \ escape-code
627///         universal-character-name
628///       escape-code:
629///         character-escape-code
630///         octal-escape-code
631///         hex-escape-code
632///       character-escape-code: one of
633///         n t b r f v a
634///         \ ' " ?
635///       octal-escape-code:
636///         octal-digit
637///         octal-digit octal-digit
638///         octal-digit octal-digit octal-digit
639///       hex-escape-code:
640///         x hex-digit
641///         hex-escape-code hex-digit
642///       universal-character-name:
643///         \u hex-quad
644///         \U hex-quad hex-quad
645///       hex-quad:
646///         hex-digit hex-digit hex-digit hex-digit
647///
648StringLiteralParser::
649StringLiteralParser(const Token *StringToks, unsigned NumStringToks,
650                    Preprocessor &pp, TargetInfo &t)
651  : PP(pp), Target(t) {
652  // Scan all of the string portions, remember the max individual token length,
653  // computing a bound on the concatenated string length, and see whether any
654  // piece is a wide-string.  If any of the string portions is a wide-string
655  // literal, the result is a wide-string literal [C99 6.4.5p4].
656  MaxTokenLength = StringToks[0].getLength();
657  SizeBound = StringToks[0].getLength()-2;  // -2 for "".
658  AnyWide = StringToks[0].is(tok::wide_string_literal);
659
660  hadError = false;
661
662  // Implement Translation Phase #6: concatenation of string literals
663  /// (C99 5.1.1.2p1).  The common case is only one string fragment.
664  for (unsigned i = 1; i != NumStringToks; ++i) {
665    // The string could be shorter than this if it needs cleaning, but this is a
666    // reasonable bound, which is all we need.
667    SizeBound += StringToks[i].getLength()-2;  // -2 for "".
668
669    // Remember maximum string piece length.
670    if (StringToks[i].getLength() > MaxTokenLength)
671      MaxTokenLength = StringToks[i].getLength();
672
673    // Remember if we see any wide strings.
674    AnyWide |= StringToks[i].is(tok::wide_string_literal);
675  }
676
677
678  // Include space for the null terminator.
679  ++SizeBound;
680
681  // TODO: K&R warning: "traditional C rejects string constant concatenation"
682
683  // Get the width in bytes of wchar_t.  If no wchar_t strings are used, do not
684  // query the target.  As such, wchar_tByteWidth is only valid if AnyWide=true.
685  wchar_tByteWidth = ~0U;
686  if (AnyWide) {
687    wchar_tByteWidth = Target.getWCharWidth();
688    assert((wchar_tByteWidth & 7) == 0 && "Assumes wchar_t is byte multiple!");
689    wchar_tByteWidth /= 8;
690  }
691
692  // The output buffer size needs to be large enough to hold wide characters.
693  // This is a worst-case assumption which basically corresponds to L"" "long".
694  if (AnyWide)
695    SizeBound *= wchar_tByteWidth;
696
697  // Size the temporary buffer to hold the result string data.
698  ResultBuf.resize(SizeBound);
699
700  // Likewise, but for each string piece.
701  llvm::SmallString<512> TokenBuf;
702  TokenBuf.resize(MaxTokenLength);
703
704  // Loop over all the strings, getting their spelling, and expanding them to
705  // wide strings as appropriate.
706  ResultPtr = &ResultBuf[0];   // Next byte to fill in.
707
708  Pascal = false;
709
710  for (unsigned i = 0, e = NumStringToks; i != e; ++i) {
711    const char *ThisTokBuf = &TokenBuf[0];
712    // Get the spelling of the token, which eliminates trigraphs, etc.  We know
713    // that ThisTokBuf points to a buffer that is big enough for the whole token
714    // and 'spelled' tokens can only shrink.
715    unsigned ThisTokLen = PP.getSpelling(StringToks[i], ThisTokBuf);
716    const char *ThisTokEnd = ThisTokBuf+ThisTokLen-1;  // Skip end quote.
717
718    // TODO: Input character set mapping support.
719
720    // Skip L marker for wide strings.
721    bool ThisIsWide = false;
722    if (ThisTokBuf[0] == 'L') {
723      ++ThisTokBuf;
724      ThisIsWide = true;
725    }
726
727    assert(ThisTokBuf[0] == '"' && "Expected quote, lexer broken?");
728    ++ThisTokBuf;
729
730    // Check if this is a pascal string
731    if (pp.getLangOptions().PascalStrings && ThisTokBuf + 1 != ThisTokEnd &&
732        ThisTokBuf[0] == '\\' && ThisTokBuf[1] == 'p') {
733
734      // If the \p sequence is found in the first token, we have a pascal string
735      // Otherwise, if we already have a pascal string, ignore the first \p
736      if (i == 0) {
737        ++ThisTokBuf;
738        Pascal = true;
739      } else if (Pascal)
740        ThisTokBuf += 2;
741    }
742
743    while (ThisTokBuf != ThisTokEnd) {
744      // Is this a span of non-escape characters?
745      if (ThisTokBuf[0] != '\\') {
746        const char *InStart = ThisTokBuf;
747        do {
748          ++ThisTokBuf;
749        } while (ThisTokBuf != ThisTokEnd && ThisTokBuf[0] != '\\');
750
751        // Copy the character span over.
752        unsigned Len = ThisTokBuf-InStart;
753        if (!AnyWide) {
754          memcpy(ResultPtr, InStart, Len);
755          ResultPtr += Len;
756        } else {
757          // Note: our internal rep of wide char tokens is always little-endian.
758          for (; Len; --Len, ++InStart) {
759            *ResultPtr++ = InStart[0];
760            // Add zeros at the end.
761            for (unsigned i = 1, e = wchar_tByteWidth; i != e; ++i)
762            *ResultPtr++ = 0;
763          }
764        }
765        continue;
766      }
767
768      // Otherwise, this is an escape character.  Process it.
769      unsigned ResultChar = ProcessCharEscape(ThisTokBuf, ThisTokEnd, hadError,
770                                              StringToks[i].getLocation(),
771                                              ThisIsWide, PP);
772
773      // Note: our internal rep of wide char tokens is always little-endian.
774      *ResultPtr++ = ResultChar & 0xFF;
775
776      if (AnyWide) {
777        for (unsigned i = 1, e = wchar_tByteWidth; i != e; ++i)
778          *ResultPtr++ = ResultChar >> i*8;
779      }
780    }
781  }
782
783  // Add zero terminator.
784  *ResultPtr = 0;
785  if (AnyWide) {
786    for (unsigned i = 1, e = wchar_tByteWidth; i != e; ++i)
787    *ResultPtr++ = 0;
788  }
789
790  if (Pascal)
791    ResultBuf[0] = ResultPtr-&ResultBuf[0]-1;
792}
793