LiteralSupport.cpp revision ac92d829111bc19d1cc97cd85c3c04bc39b969d1 
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        hadError = true;
384      }
385    } else if (saw_period) {
386      PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin),
387              diag::err_hexconstant_requires_exponent);
388      hadError = true;
389    }
390    return;
391  }
392
393  // Handle simple binary numbers 0b01010
394  if (*s == 'b' || *s == 'B') {
395    // 0b101010 is a GCC extension.
396    PP.Diag(TokLoc, diag::ext_binary_literal);
397    ++s;
398    radix = 2;
399    DigitsBegin = s;
400    s = SkipBinaryDigits(s);
401    if (s == ThisTokEnd) {
402      // Done.
403    } else if (isxdigit(*s)) {
404      PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin),
405              diag::err_invalid_binary_digit) << std::string(s, s+1);
406      hadError = true;
407    }
408    // Other suffixes will be diagnosed by the caller.
409    return;
410  }
411
412  // For now, the radix is set to 8. If we discover that we have a
413  // floating point constant, the radix will change to 10. Octal floating
414  // point constants are not permitted (only decimal and hexadecimal).
415  radix = 8;
416  DigitsBegin = s;
417  s = SkipOctalDigits(s);
418  if (s == ThisTokEnd)
419    return; // Done, simple octal number like 01234
420
421  // If we have some other non-octal digit that *is* a decimal digit, see if
422  // this is part of a floating point number like 094.123 or 09e1.
423  if (isdigit(*s)) {
424    const char *EndDecimal = SkipDigits(s);
425    if (EndDecimal[0] == '.' || EndDecimal[0] == 'e' || EndDecimal[0] == 'E') {
426      s = EndDecimal;
427      radix = 10;
428    }
429  }
430
431  // If we have a hex digit other than 'e' (which denotes a FP exponent) then
432  // the code is using an incorrect base.
433  if (isxdigit(*s) && *s != 'e' && *s != 'E') {
434    PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin),
435            diag::err_invalid_octal_digit) << std::string(s, s+1);
436    hadError = true;
437    return;
438  }
439
440  if (*s == '.') {
441    s++;
442    radix = 10;
443    saw_period = true;
444    s = SkipDigits(s); // Skip suffix.
445  }
446  if (*s == 'e' || *s == 'E') { // exponent
447    const char *Exponent = s;
448    s++;
449    radix = 10;
450    saw_exponent = true;
451    if (*s == '+' || *s == '-')  s++; // sign
452    const char *first_non_digit = SkipDigits(s);
453    if (first_non_digit != s) {
454      s = first_non_digit;
455    } else {
456      PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Exponent-ThisTokBegin),
457              diag::err_exponent_has_no_digits);
458      hadError = true;
459      return;
460    }
461  }
462}
463
464
465/// GetIntegerValue - Convert this numeric literal value to an APInt that
466/// matches Val's input width.  If there is an overflow, set Val to the low bits
467/// of the result and return true.  Otherwise, return false.
468bool NumericLiteralParser::GetIntegerValue(llvm::APInt &Val) {
469  // Fast path: Compute a conservative bound on the maximum number of
470  // bits per digit in this radix. If we can't possibly overflow a
471  // uint64 based on that bound then do the simple conversion to
472  // integer. This avoids the expensive overflow checking below, and
473  // handles the common cases that matter (small decimal integers and
474  // hex/octal values which don't overflow).
475  unsigned MaxBitsPerDigit = 1;
476  while ((1U << MaxBitsPerDigit) < radix)
477    MaxBitsPerDigit += 1;
478  if ((SuffixBegin - DigitsBegin) * MaxBitsPerDigit <= 64) {
479    uint64_t N = 0;
480    for (s = DigitsBegin; s != SuffixBegin; ++s)
481      N = N*radix + HexDigitValue(*s);
482
483    // This will truncate the value to Val's input width. Simply check
484    // for overflow by comparing.
485    Val = N;
486    return Val.getZExtValue() != N;
487  }
488
489  Val = 0;
490  s = DigitsBegin;
491
492  llvm::APInt RadixVal(Val.getBitWidth(), radix);
493  llvm::APInt CharVal(Val.getBitWidth(), 0);
494  llvm::APInt OldVal = Val;
495
496  bool OverflowOccurred = false;
497  while (s < SuffixBegin) {
498    unsigned C = HexDigitValue(*s++);
499
500    // If this letter is out of bound for this radix, reject it.
501    assert(C < radix && "NumericLiteralParser ctor should have rejected this");
502
503    CharVal = C;
504
505    // Add the digit to the value in the appropriate radix.  If adding in digits
506    // made the value smaller, then this overflowed.
507    OldVal = Val;
508
509    // Multiply by radix, did overflow occur on the multiply?
510    Val *= RadixVal;
511    OverflowOccurred |= Val.udiv(RadixVal) != OldVal;
512
513    // Add value, did overflow occur on the value?
514    //   (a + b) ult b  <=> overflow
515    Val += CharVal;
516    OverflowOccurred |= Val.ult(CharVal);
517  }
518  return OverflowOccurred;
519}
520
521llvm::APFloat NumericLiteralParser::
522GetFloatValue(const llvm::fltSemantics &Format, bool* isExact) {
523  using llvm::APFloat;
524
525  llvm::SmallVector<char,256> floatChars;
526  for (unsigned i = 0, n = ThisTokEnd-ThisTokBegin; i != n; ++i)
527    floatChars.push_back(ThisTokBegin[i]);
528
529  floatChars.push_back('\0');
530
531  APFloat V (Format, APFloat::fcZero, false);
532  APFloat::opStatus status;
533
534  status = V.convertFromString(&floatChars[0],APFloat::rmNearestTiesToEven);
535
536  if (isExact)
537    *isExact = status == APFloat::opOK;
538
539  return V;
540}
541
542
543CharLiteralParser::CharLiteralParser(const char *begin, const char *end,
544                                     SourceLocation Loc, Preprocessor &PP) {
545  // At this point we know that the character matches the regex "L?'.*'".
546  HadError = false;
547  Value = 0;
548
549  // Determine if this is a wide character.
550  IsWide = begin[0] == 'L';
551  if (IsWide) ++begin;
552
553  // Skip over the entry quote.
554  assert(begin[0] == '\'' && "Invalid token lexed");
555  ++begin;
556
557  // FIXME: This assumes that 'int' is 32-bits in overflow calculation, and the
558  // size of "value".
559  assert(PP.getTargetInfo().getIntWidth() == 32 &&
560         "Assumes sizeof(int) == 4 for now");
561  // FIXME: This assumes that wchar_t is 32-bits for now.
562  assert(PP.getTargetInfo().getWCharWidth() == 32 &&
563         "Assumes sizeof(wchar_t) == 4 for now");
564  // FIXME: This extensively assumes that 'char' is 8-bits.
565  assert(PP.getTargetInfo().getCharWidth() == 8 &&
566         "Assumes char is 8 bits");
567
568  bool isFirstChar = true;
569  bool isMultiChar = false;
570  while (begin[0] != '\'') {
571    unsigned ResultChar;
572    if (begin[0] != '\\')     // If this is a normal character, consume it.
573      ResultChar = *begin++;
574    else                      // Otherwise, this is an escape character.
575      ResultChar = ProcessCharEscape(begin, end, HadError, Loc, IsWide, PP);
576
577    // If this is a multi-character constant (e.g. 'abc'), handle it.  These are
578    // implementation defined (C99 6.4.4.4p10).
579    if (!isFirstChar) {
580      // If this is the second character being processed, do special handling.
581      if (!isMultiChar) {
582        isMultiChar = true;
583
584        // Warn about discarding the top bits for multi-char wide-character
585        // constants (L'abcd').
586        if (IsWide)
587          PP.Diag(Loc, diag::warn_extraneous_wide_char_constant);
588      }
589
590      if (IsWide) {
591        // Emulate GCC's (unintentional?) behavior: L'ab' -> L'b'.
592        Value = 0;
593      } else {
594        // Narrow character literals act as though their value is concatenated
595        // in this implementation.
596        if (((Value << 8) >> 8) != Value)
597          PP.Diag(Loc, diag::warn_char_constant_too_large);
598        Value <<= 8;
599      }
600    }
601
602    Value += ResultChar;
603    isFirstChar = false;
604  }
605
606  // If this is a single narrow character, sign extend it (e.g. '\xFF' is "-1")
607  // if 'char' is signed for this target (C99 6.4.4.4p10).  Note that multiple
608  // character constants are not sign extended in the this implementation:
609  // '\xFF\xFF' = 65536 and '\x0\xFF' = 255, which matches GCC.
610  if (!IsWide && !isMultiChar && (Value & 128) &&
611      PP.getTargetInfo().isCharSigned())
612    Value = (signed char)Value;
613}
614
615
616///       string-literal: [C99 6.4.5]
617///          " [s-char-sequence] "
618///         L" [s-char-sequence] "
619///       s-char-sequence:
620///         s-char
621///         s-char-sequence s-char
622///       s-char:
623///         any source character except the double quote ",
624///           backslash \, or newline character
625///         escape-character
626///         universal-character-name
627///       escape-character: [C99 6.4.4.4]
628///         \ escape-code
629///         universal-character-name
630///       escape-code:
631///         character-escape-code
632///         octal-escape-code
633///         hex-escape-code
634///       character-escape-code: one of
635///         n t b r f v a
636///         \ ' " ?
637///       octal-escape-code:
638///         octal-digit
639///         octal-digit octal-digit
640///         octal-digit octal-digit octal-digit
641///       hex-escape-code:
642///         x hex-digit
643///         hex-escape-code hex-digit
644///       universal-character-name:
645///         \u hex-quad
646///         \U hex-quad hex-quad
647///       hex-quad:
648///         hex-digit hex-digit hex-digit hex-digit
649///
650StringLiteralParser::
651StringLiteralParser(const Token *StringToks, unsigned NumStringToks,
652                    Preprocessor &pp, TargetInfo &t)
653  : PP(pp), Target(t) {
654  // Scan all of the string portions, remember the max individual token length,
655  // computing a bound on the concatenated string length, and see whether any
656  // piece is a wide-string.  If any of the string portions is a wide-string
657  // literal, the result is a wide-string literal [C99 6.4.5p4].
658  MaxTokenLength = StringToks[0].getLength();
659  SizeBound = StringToks[0].getLength()-2;  // -2 for "".
660  AnyWide = StringToks[0].is(tok::wide_string_literal);
661
662  hadError = false;
663
664  // Implement Translation Phase #6: concatenation of string literals
665  /// (C99 5.1.1.2p1).  The common case is only one string fragment.
666  for (unsigned i = 1; i != NumStringToks; ++i) {
667    // The string could be shorter than this if it needs cleaning, but this is a
668    // reasonable bound, which is all we need.
669    SizeBound += StringToks[i].getLength()-2;  // -2 for "".
670
671    // Remember maximum string piece length.
672    if (StringToks[i].getLength() > MaxTokenLength)
673      MaxTokenLength = StringToks[i].getLength();
674
675    // Remember if we see any wide strings.
676    AnyWide |= StringToks[i].is(tok::wide_string_literal);
677  }
678
679
680  // Include space for the null terminator.
681  ++SizeBound;
682
683  // TODO: K&R warning: "traditional C rejects string constant concatenation"
684
685  // Get the width in bytes of wchar_t.  If no wchar_t strings are used, do not
686  // query the target.  As such, wchar_tByteWidth is only valid if AnyWide=true.
687  wchar_tByteWidth = ~0U;
688  if (AnyWide) {
689    wchar_tByteWidth = Target.getWCharWidth();
690    assert((wchar_tByteWidth & 7) == 0 && "Assumes wchar_t is byte multiple!");
691    wchar_tByteWidth /= 8;
692  }
693
694  // The output buffer size needs to be large enough to hold wide characters.
695  // This is a worst-case assumption which basically corresponds to L"" "long".
696  if (AnyWide)
697    SizeBound *= wchar_tByteWidth;
698
699  // Size the temporary buffer to hold the result string data.
700  ResultBuf.resize(SizeBound);
701
702  // Likewise, but for each string piece.
703  llvm::SmallString<512> TokenBuf;
704  TokenBuf.resize(MaxTokenLength);
705
706  // Loop over all the strings, getting their spelling, and expanding them to
707  // wide strings as appropriate.
708  ResultPtr = &ResultBuf[0];   // Next byte to fill in.
709
710  Pascal = false;
711
712  for (unsigned i = 0, e = NumStringToks; i != e; ++i) {
713    const char *ThisTokBuf = &TokenBuf[0];
714    // Get the spelling of the token, which eliminates trigraphs, etc.  We know
715    // that ThisTokBuf points to a buffer that is big enough for the whole token
716    // and 'spelled' tokens can only shrink.
717    unsigned ThisTokLen = PP.getSpelling(StringToks[i], ThisTokBuf);
718    const char *ThisTokEnd = ThisTokBuf+ThisTokLen-1;  // Skip end quote.
719
720    // TODO: Input character set mapping support.
721
722    // Skip L marker for wide strings.
723    bool ThisIsWide = false;
724    if (ThisTokBuf[0] == 'L') {
725      ++ThisTokBuf;
726      ThisIsWide = true;
727    }
728
729    assert(ThisTokBuf[0] == '"' && "Expected quote, lexer broken?");
730    ++ThisTokBuf;
731
732    // Check if this is a pascal string
733    if (pp.getLangOptions().PascalStrings && ThisTokBuf + 1 != ThisTokEnd &&
734        ThisTokBuf[0] == '\\' && ThisTokBuf[1] == 'p') {
735
736      // If the \p sequence is found in the first token, we have a pascal string
737      // Otherwise, if we already have a pascal string, ignore the first \p
738      if (i == 0) {
739        ++ThisTokBuf;
740        Pascal = true;
741      } else if (Pascal)
742        ThisTokBuf += 2;
743    }
744
745    while (ThisTokBuf != ThisTokEnd) {
746      // Is this a span of non-escape characters?
747      if (ThisTokBuf[0] != '\\') {
748        const char *InStart = ThisTokBuf;
749        do {
750          ++ThisTokBuf;
751        } while (ThisTokBuf != ThisTokEnd && ThisTokBuf[0] != '\\');
752
753        // Copy the character span over.
754        unsigned Len = ThisTokBuf-InStart;
755        if (!AnyWide) {
756          memcpy(ResultPtr, InStart, Len);
757          ResultPtr += Len;
758        } else {
759          // Note: our internal rep of wide char tokens is always little-endian.
760          for (; Len; --Len, ++InStart) {
761            *ResultPtr++ = InStart[0];
762            // Add zeros at the end.
763            for (unsigned i = 1, e = wchar_tByteWidth; i != e; ++i)
764            *ResultPtr++ = 0;
765          }
766        }
767        continue;
768      }
769
770      // Otherwise, this is an escape character.  Process it.
771      unsigned ResultChar = ProcessCharEscape(ThisTokBuf, ThisTokEnd, hadError,
772                                              StringToks[i].getLocation(),
773                                              ThisIsWide, PP);
774
775      // Note: our internal rep of wide char tokens is always little-endian.
776      *ResultPtr++ = ResultChar & 0xFF;
777
778      if (AnyWide) {
779        for (unsigned i = 1, e = wchar_tByteWidth; i != e; ++i)
780          *ResultPtr++ = ResultChar >> i*8;
781      }
782    }
783  }
784
785  // Add zero terminator.
786  *ResultPtr = 0;
787  if (AnyWide) {
788    for (unsigned i = 1, e = wchar_tByteWidth; i != e; ++i)
789    *ResultPtr++ = 0;
790  }
791
792  if (Pascal)
793    ResultBuf[0] = ResultPtr-&ResultBuf[0]-1;
794}
795