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Diffstat (limited to 'lib/Lex/LiteralSupport.cpp')
| -rw-r--r-- | lib/Lex/LiteralSupport.cpp | 929 |
1 files changed, 929 insertions, 0 deletions
diff --git a/lib/Lex/LiteralSupport.cpp b/lib/Lex/LiteralSupport.cpp new file mode 100644 index 0000000..0324c0b --- /dev/null +++ b/lib/Lex/LiteralSupport.cpp @@ -0,0 +1,929 @@ +//===--- LiteralSupport.cpp - Code to parse and process literals ----------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements the NumericLiteralParser, CharLiteralParser, and +// StringLiteralParser interfaces. +// +//===----------------------------------------------------------------------===// + +#include "clang/Lex/LiteralSupport.h" +#include "clang/Lex/Preprocessor.h" +#include "clang/Lex/LexDiagnostic.h" +#include "clang/Basic/TargetInfo.h" +#include "llvm/ADT/StringExtras.h" +using namespace clang; + +/// HexDigitValue - Return the value of the specified hex digit, or -1 if it's +/// not valid. +static int HexDigitValue(char C) { + if (C >= '0' && C <= '9') return C-'0'; + if (C >= 'a' && C <= 'f') return C-'a'+10; + if (C >= 'A' && C <= 'F') return C-'A'+10; + return -1; +} + +/// ProcessCharEscape - Parse a standard C escape sequence, which can occur in +/// either a character or a string literal. +static unsigned ProcessCharEscape(const char *&ThisTokBuf, + const char *ThisTokEnd, bool &HadError, + SourceLocation Loc, bool IsWide, + Preprocessor &PP) { + // Skip the '\' char. + ++ThisTokBuf; + + // We know that this character can't be off the end of the buffer, because + // that would have been \", which would not have been the end of string. + unsigned ResultChar = *ThisTokBuf++; + switch (ResultChar) { + // These map to themselves. + case '\\': case '\'': case '"': case '?': break; + + // These have fixed mappings. + case 'a': + // TODO: K&R: the meaning of '\\a' is different in traditional C + ResultChar = 7; + break; + case 'b': + ResultChar = 8; + break; + case 'e': + PP.Diag(Loc, diag::ext_nonstandard_escape) << "e"; + ResultChar = 27; + break; + case 'f': + ResultChar = 12; + break; + case 'n': + ResultChar = 10; + break; + case 'r': + ResultChar = 13; + break; + case 't': + ResultChar = 9; + break; + case 'v': + ResultChar = 11; + break; + case 'x': { // Hex escape. + ResultChar = 0; + if (ThisTokBuf == ThisTokEnd || !isxdigit(*ThisTokBuf)) { + PP.Diag(Loc, diag::err_hex_escape_no_digits); + HadError = 1; + break; + } + + // Hex escapes are a maximal series of hex digits. + bool Overflow = false; + for (; ThisTokBuf != ThisTokEnd; ++ThisTokBuf) { + int CharVal = HexDigitValue(ThisTokBuf[0]); + if (CharVal == -1) break; + // About to shift out a digit? + Overflow |= (ResultChar & 0xF0000000) ? true : false; + ResultChar <<= 4; + ResultChar |= CharVal; + } + + // See if any bits will be truncated when evaluated as a character. + unsigned CharWidth = PP.getTargetInfo().getCharWidth(IsWide); + + if (CharWidth != 32 && (ResultChar >> CharWidth) != 0) { + Overflow = true; + ResultChar &= ~0U >> (32-CharWidth); + } + + // Check for overflow. + if (Overflow) // Too many digits to fit in + PP.Diag(Loc, diag::warn_hex_escape_too_large); + break; + } + case '0': case '1': case '2': case '3': + case '4': case '5': case '6': case '7': { + // Octal escapes. + --ThisTokBuf; + ResultChar = 0; + + // Octal escapes are a series of octal digits with maximum length 3. + // "\0123" is a two digit sequence equal to "\012" "3". + unsigned NumDigits = 0; + do { + ResultChar <<= 3; + ResultChar |= *ThisTokBuf++ - '0'; + ++NumDigits; + } while (ThisTokBuf != ThisTokEnd && NumDigits < 3 && + ThisTokBuf[0] >= '0' && ThisTokBuf[0] <= '7'); + + // Check for overflow. Reject '\777', but not L'\777'. + unsigned CharWidth = PP.getTargetInfo().getCharWidth(IsWide); + + if (CharWidth != 32 && (ResultChar >> CharWidth) != 0) { + PP.Diag(Loc, diag::warn_octal_escape_too_large); + ResultChar &= ~0U >> (32-CharWidth); + } + break; + } + + // Otherwise, these are not valid escapes. + case '(': case '{': case '[': case '%': + // GCC accepts these as extensions. We warn about them as such though. + PP.Diag(Loc, diag::ext_nonstandard_escape) + << std::string()+(char)ResultChar; + break; + // FALL THROUGH. + default: + if (isgraph(ThisTokBuf[0])) + PP.Diag(Loc, diag::ext_unknown_escape) << std::string()+(char)ResultChar; + else + PP.Diag(Loc, diag::ext_unknown_escape) << "x"+llvm::utohexstr(ResultChar); + break; + } + + return ResultChar; +} + +/// ProcessUCNEscape - Read the Universal Character Name, check constraints and +/// convert the UTF32 to UTF8. This is a subroutine of StringLiteralParser. +/// When we decide to implement UCN's for character constants and identifiers, +/// we will likely rework our support for UCN's. +static void ProcessUCNEscape(const char *&ThisTokBuf, const char *ThisTokEnd, + char *&ResultBuf, bool &HadError, + SourceLocation Loc, bool IsWide, Preprocessor &PP) +{ + // FIXME: Add a warning - UCN's are only valid in C++ & C99. + // FIXME: Handle wide strings. + + // Save the beginning of the string (for error diagnostics). + const char *ThisTokBegin = ThisTokBuf; + + // Skip the '\u' char's. + ThisTokBuf += 2; + + if (ThisTokBuf == ThisTokEnd || !isxdigit(*ThisTokBuf)) { + PP.Diag(Loc, diag::err_ucn_escape_no_digits); + HadError = 1; + return; + } + typedef uint32_t UTF32; + + UTF32 UcnVal = 0; + unsigned short UcnLen = (ThisTokBuf[-1] == 'u' ? 4 : 8); + for (; ThisTokBuf != ThisTokEnd && UcnLen; ++ThisTokBuf, UcnLen--) { + int CharVal = HexDigitValue(ThisTokBuf[0]); + if (CharVal == -1) break; + UcnVal <<= 4; + UcnVal |= CharVal; + } + // If we didn't consume the proper number of digits, there is a problem. + if (UcnLen) { + PP.Diag(PP.AdvanceToTokenCharacter(Loc, ThisTokBuf-ThisTokBegin), + diag::err_ucn_escape_incomplete); + HadError = 1; + return; + } + // Check UCN constraints (C99 6.4.3p2). + if ((UcnVal < 0xa0 && + (UcnVal != 0x24 && UcnVal != 0x40 && UcnVal != 0x60 )) // $, @, ` + || (UcnVal >= 0xD800 && UcnVal <= 0xDFFF) + || (UcnVal > 0x10FFFF)) /* the maximum legal UTF32 value */ { + PP.Diag(Loc, diag::err_ucn_escape_invalid); + HadError = 1; + return; + } + // Now that we've parsed/checked the UCN, we convert from UTF32->UTF8. + // The conversion below was inspired by: + // http://www.unicode.org/Public/PROGRAMS/CVTUTF/ConvertUTF.c + // First, we determine how many bytes the result will require. + typedef uint8_t UTF8; + + unsigned short bytesToWrite = 0; + if (UcnVal < (UTF32)0x80) + bytesToWrite = 1; + else if (UcnVal < (UTF32)0x800) + bytesToWrite = 2; + else if (UcnVal < (UTF32)0x10000) + bytesToWrite = 3; + else + bytesToWrite = 4; + + const unsigned byteMask = 0xBF; + const unsigned byteMark = 0x80; + + // Once the bits are split out into bytes of UTF8, this is a mask OR-ed + // into the first byte, depending on how many bytes follow. + static const UTF8 firstByteMark[5] = { + 0x00, 0x00, 0xC0, 0xE0, 0xF0 + }; + // Finally, we write the bytes into ResultBuf. + ResultBuf += bytesToWrite; + switch (bytesToWrite) { // note: everything falls through. + case 4: *--ResultBuf = (UTF8)((UcnVal | byteMark) & byteMask); UcnVal >>= 6; + case 3: *--ResultBuf = (UTF8)((UcnVal | byteMark) & byteMask); UcnVal >>= 6; + case 2: *--ResultBuf = (UTF8)((UcnVal | byteMark) & byteMask); UcnVal >>= 6; + case 1: *--ResultBuf = (UTF8) (UcnVal | firstByteMark[bytesToWrite]); + } + // Update the buffer. + ResultBuf += bytesToWrite; +} + + +/// integer-constant: [C99 6.4.4.1] +/// decimal-constant integer-suffix +/// octal-constant integer-suffix +/// hexadecimal-constant integer-suffix +/// decimal-constant: +/// nonzero-digit +/// decimal-constant digit +/// octal-constant: +/// 0 +/// octal-constant octal-digit +/// hexadecimal-constant: +/// hexadecimal-prefix hexadecimal-digit +/// hexadecimal-constant hexadecimal-digit +/// hexadecimal-prefix: one of +/// 0x 0X +/// integer-suffix: +/// unsigned-suffix [long-suffix] +/// unsigned-suffix [long-long-suffix] +/// long-suffix [unsigned-suffix] +/// long-long-suffix [unsigned-sufix] +/// nonzero-digit: +/// 1 2 3 4 5 6 7 8 9 +/// octal-digit: +/// 0 1 2 3 4 5 6 7 +/// hexadecimal-digit: +/// 0 1 2 3 4 5 6 7 8 9 +/// a b c d e f +/// A B C D E F +/// unsigned-suffix: one of +/// u U +/// long-suffix: one of +/// l L +/// long-long-suffix: one of +/// ll LL +/// +/// floating-constant: [C99 6.4.4.2] +/// TODO: add rules... +/// +NumericLiteralParser:: +NumericLiteralParser(const char *begin, const char *end, + SourceLocation TokLoc, Preprocessor &pp) + : PP(pp), ThisTokBegin(begin), ThisTokEnd(end) { + + // This routine assumes that the range begin/end matches the regex for integer + // and FP constants (specifically, the 'pp-number' regex), and assumes that + // the byte at "*end" is both valid and not part of the regex. Because of + // this, it doesn't have to check for 'overscan' in various places. + assert(!isalnum(*end) && *end != '.' && *end != '_' && + "Lexer didn't maximally munch?"); + + s = DigitsBegin = begin; + saw_exponent = false; + saw_period = false; + isLong = false; + isUnsigned = false; + isLongLong = false; + isFloat = false; + isImaginary = false; + hadError = false; + + if (*s == '0') { // parse radix + ParseNumberStartingWithZero(TokLoc); + if (hadError) + return; + } else { // the first digit is non-zero + radix = 10; + s = SkipDigits(s); + if (s == ThisTokEnd) { + // Done. + } else if (isxdigit(*s) && !(*s == 'e' || *s == 'E')) { + PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-begin), + diag::err_invalid_decimal_digit) << std::string(s, s+1); + hadError = true; + return; + } else if (*s == '.') { + s++; + saw_period = true; + s = SkipDigits(s); + } + if ((*s == 'e' || *s == 'E')) { // exponent + const char *Exponent = s; + s++; + saw_exponent = true; + if (*s == '+' || *s == '-') s++; // sign + const char *first_non_digit = SkipDigits(s); + if (first_non_digit != s) { + s = first_non_digit; + } else { + PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Exponent-begin), + diag::err_exponent_has_no_digits); + hadError = true; + return; + } + } + } + + SuffixBegin = s; + + // Parse the suffix. At this point we can classify whether we have an FP or + // integer constant. + bool isFPConstant = isFloatingLiteral(); + + // Loop over all of the characters of the suffix. If we see something bad, + // we break out of the loop. + for (; s != ThisTokEnd; ++s) { + switch (*s) { + case 'f': // FP Suffix for "float" + case 'F': + if (!isFPConstant) break; // Error for integer constant. + if (isFloat || isLong) break; // FF, LF invalid. + isFloat = true; + continue; // Success. + case 'u': + case 'U': + if (isFPConstant) break; // Error for floating constant. + if (isUnsigned) break; // Cannot be repeated. + isUnsigned = true; + continue; // Success. + case 'l': + case 'L': + if (isLong || isLongLong) break; // Cannot be repeated. + if (isFloat) break; // LF invalid. + + // Check for long long. The L's need to be adjacent and the same case. + if (s+1 != ThisTokEnd && s[1] == s[0]) { + if (isFPConstant) break; // long long invalid for floats. + isLongLong = true; + ++s; // Eat both of them. + } else { + isLong = true; + } + continue; // Success. + case 'i': + if (PP.getLangOptions().Microsoft) { + // Allow i8, i16, i32, i64, and i128. + if (++s == ThisTokEnd) break; + switch (*s) { + case '8': + s++; // i8 suffix + break; + case '1': + if (++s == ThisTokEnd) break; + if (*s == '6') s++; // i16 suffix + else if (*s == '2') { + if (++s == ThisTokEnd) break; + if (*s == '8') s++; // i128 suffix + } + break; + case '3': + if (++s == ThisTokEnd) break; + if (*s == '2') s++; // i32 suffix + break; + case '6': + if (++s == ThisTokEnd) break; + if (*s == '4') s++; // i64 suffix + break; + default: + break; + } + break; + } + // fall through. + case 'I': + case 'j': + case 'J': + if (isImaginary) break; // Cannot be repeated. + PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-begin), + diag::ext_imaginary_constant); + isImaginary = true; + continue; // Success. + } + // If we reached here, there was an error. + break; + } + + // Report an error if there are any. + if (s != ThisTokEnd) { + PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-begin), + isFPConstant ? diag::err_invalid_suffix_float_constant : + diag::err_invalid_suffix_integer_constant) + << std::string(SuffixBegin, ThisTokEnd); + hadError = true; + return; + } +} + +/// ParseNumberStartingWithZero - This method is called when the first character +/// of the number is found to be a zero. This means it is either an octal +/// number (like '04') or a hex number ('0x123a') a binary number ('0b1010') or +/// a floating point number (01239.123e4). Eat the prefix, determining the +/// radix etc. +void NumericLiteralParser::ParseNumberStartingWithZero(SourceLocation TokLoc) { + assert(s[0] == '0' && "Invalid method call"); + s++; + + // Handle a hex number like 0x1234. + if ((*s == 'x' || *s == 'X') && (isxdigit(s[1]) || s[1] == '.')) { + s++; + radix = 16; + DigitsBegin = s; + s = SkipHexDigits(s); + if (s == ThisTokEnd) { + // Done. + } else if (*s == '.') { + s++; + saw_period = true; + s = SkipHexDigits(s); + } + // A binary exponent can appear with or with a '.'. If dotted, the + // binary exponent is required. + if (*s == 'p' || *s == 'P') { + const char *Exponent = s; + s++; + saw_exponent = true; + if (*s == '+' || *s == '-') s++; // sign + const char *first_non_digit = SkipDigits(s); + if (first_non_digit == s) { + PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Exponent-ThisTokBegin), + diag::err_exponent_has_no_digits); + hadError = true; + return; + } + s = first_non_digit; + + if (!PP.getLangOptions().HexFloats) + PP.Diag(TokLoc, diag::ext_hexconstant_invalid); + } else if (saw_period) { + PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin), + diag::err_hexconstant_requires_exponent); + hadError = true; + } + return; + } + + // Handle simple binary numbers 0b01010 + if (*s == 'b' || *s == 'B') { + // 0b101010 is a GCC extension. + PP.Diag(TokLoc, diag::ext_binary_literal); + ++s; + radix = 2; + DigitsBegin = s; + s = SkipBinaryDigits(s); + if (s == ThisTokEnd) { + // Done. + } else if (isxdigit(*s)) { + PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin), + diag::err_invalid_binary_digit) << std::string(s, s+1); + hadError = true; + } + // Other suffixes will be diagnosed by the caller. + return; + } + + // For now, the radix is set to 8. If we discover that we have a + // floating point constant, the radix will change to 10. Octal floating + // point constants are not permitted (only decimal and hexadecimal). + radix = 8; + DigitsBegin = s; + s = SkipOctalDigits(s); + if (s == ThisTokEnd) + return; // Done, simple octal number like 01234 + + // If we have some other non-octal digit that *is* a decimal digit, see if + // this is part of a floating point number like 094.123 or 09e1. + if (isdigit(*s)) { + const char *EndDecimal = SkipDigits(s); + if (EndDecimal[0] == '.' || EndDecimal[0] == 'e' || EndDecimal[0] == 'E') { + s = EndDecimal; + radix = 10; + } + } + + // If we have a hex digit other than 'e' (which denotes a FP exponent) then + // the code is using an incorrect base. + if (isxdigit(*s) && *s != 'e' && *s != 'E') { + PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin), + diag::err_invalid_octal_digit) << std::string(s, s+1); + hadError = true; + return; + } + + if (*s == '.') { + s++; + radix = 10; + saw_period = true; + s = SkipDigits(s); // Skip suffix. + } + if (*s == 'e' || *s == 'E') { // exponent + const char *Exponent = s; + s++; + radix = 10; + saw_exponent = true; + if (*s == '+' || *s == '-') s++; // sign + const char *first_non_digit = SkipDigits(s); + if (first_non_digit != s) { + s = first_non_digit; + } else { + PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Exponent-ThisTokBegin), + diag::err_exponent_has_no_digits); + hadError = true; + return; + } + } +} + + +/// GetIntegerValue - Convert this numeric literal value to an APInt that +/// matches Val's input width. If there is an overflow, set Val to the low bits +/// of the result and return true. Otherwise, return false. +bool NumericLiteralParser::GetIntegerValue(llvm::APInt &Val) { + // Fast path: Compute a conservative bound on the maximum number of + // bits per digit in this radix. If we can't possibly overflow a + // uint64 based on that bound then do the simple conversion to + // integer. This avoids the expensive overflow checking below, and + // handles the common cases that matter (small decimal integers and + // hex/octal values which don't overflow). + unsigned MaxBitsPerDigit = 1; + while ((1U << MaxBitsPerDigit) < radix) + MaxBitsPerDigit += 1; + if ((SuffixBegin - DigitsBegin) * MaxBitsPerDigit <= 64) { + uint64_t N = 0; + for (s = DigitsBegin; s != SuffixBegin; ++s) + N = N*radix + HexDigitValue(*s); + + // This will truncate the value to Val's input width. Simply check + // for overflow by comparing. + Val = N; + return Val.getZExtValue() != N; + } + + Val = 0; + s = DigitsBegin; + + llvm::APInt RadixVal(Val.getBitWidth(), radix); + llvm::APInt CharVal(Val.getBitWidth(), 0); + llvm::APInt OldVal = Val; + + bool OverflowOccurred = false; + while (s < SuffixBegin) { + unsigned C = HexDigitValue(*s++); + + // If this letter is out of bound for this radix, reject it. + assert(C < radix && "NumericLiteralParser ctor should have rejected this"); + + CharVal = C; + + // Add the digit to the value in the appropriate radix. If adding in digits + // made the value smaller, then this overflowed. + OldVal = Val; + + // Multiply by radix, did overflow occur on the multiply? + Val *= RadixVal; + OverflowOccurred |= Val.udiv(RadixVal) != OldVal; + + // Add value, did overflow occur on the value? + // (a + b) ult b <=> overflow + Val += CharVal; + OverflowOccurred |= Val.ult(CharVal); + } + return OverflowOccurred; +} + +llvm::APFloat NumericLiteralParser:: +GetFloatValue(const llvm::fltSemantics &Format, bool* isExact) { + using llvm::APFloat; + + llvm::SmallVector<char,256> floatChars; + for (unsigned i = 0, n = ThisTokEnd-ThisTokBegin; i != n; ++i) + floatChars.push_back(ThisTokBegin[i]); + + floatChars.push_back('\0'); + + APFloat V (Format, APFloat::fcZero, false); + APFloat::opStatus status; + + status = V.convertFromString(&floatChars[0],APFloat::rmNearestTiesToEven); + + if (isExact) + *isExact = status == APFloat::opOK; + + return V; +} + + +CharLiteralParser::CharLiteralParser(const char *begin, const char *end, + SourceLocation Loc, Preprocessor &PP) { + // At this point we know that the character matches the regex "L?'.*'". + HadError = false; + + // Determine if this is a wide character. + IsWide = begin[0] == 'L'; + if (IsWide) ++begin; + + // Skip over the entry quote. + assert(begin[0] == '\'' && "Invalid token lexed"); + ++begin; + + // FIXME: The "Value" is an uint64_t so we can handle char literals of + // upto 64-bits. + // FIXME: This extensively assumes that 'char' is 8-bits. + assert(PP.getTargetInfo().getCharWidth() == 8 && + "Assumes char is 8 bits"); + assert(PP.getTargetInfo().getIntWidth() <= 64 && + (PP.getTargetInfo().getIntWidth() & 7) == 0 && + "Assumes sizeof(int) on target is <= 64 and a multiple of char"); + assert(PP.getTargetInfo().getWCharWidth() <= 64 && + "Assumes sizeof(wchar) on target is <= 64"); + + // This is what we will use for overflow detection + llvm::APInt LitVal(PP.getTargetInfo().getIntWidth(), 0); + + unsigned NumCharsSoFar = 0; + while (begin[0] != '\'') { + uint64_t ResultChar; + if (begin[0] != '\\') // If this is a normal character, consume it. + ResultChar = *begin++; + else // Otherwise, this is an escape character. + ResultChar = ProcessCharEscape(begin, end, HadError, Loc, IsWide, PP); + + // If this is a multi-character constant (e.g. 'abc'), handle it. These are + // implementation defined (C99 6.4.4.4p10). + if (NumCharsSoFar) { + if (IsWide) { + // Emulate GCC's (unintentional?) behavior: L'ab' -> L'b'. + LitVal = 0; + } else { + // Narrow character literals act as though their value is concatenated + // in this implementation, but warn on overflow. + if (LitVal.countLeadingZeros() < 8) + PP.Diag(Loc, diag::warn_char_constant_too_large); + LitVal <<= 8; + } + } + + LitVal = LitVal + ResultChar; + ++NumCharsSoFar; + } + + // If this is the second character being processed, do special handling. + if (NumCharsSoFar > 1) { + // Warn about discarding the top bits for multi-char wide-character + // constants (L'abcd'). + if (IsWide) + PP.Diag(Loc, diag::warn_extraneous_wide_char_constant); + else if (NumCharsSoFar != 4) + PP.Diag(Loc, diag::ext_multichar_character_literal); + else + PP.Diag(Loc, diag::ext_four_char_character_literal); + IsMultiChar = true; + } + + // Transfer the value from APInt to uint64_t + Value = LitVal.getZExtValue(); + + // If this is a single narrow character, sign extend it (e.g. '\xFF' is "-1") + // if 'char' is signed for this target (C99 6.4.4.4p10). Note that multiple + // character constants are not sign extended in the this implementation: + // '\xFF\xFF' = 65536 and '\x0\xFF' = 255, which matches GCC. + if (!IsWide && NumCharsSoFar == 1 && (Value & 128) && + PP.getTargetInfo().isCharSigned()) + Value = (signed char)Value; +} + + +/// string-literal: [C99 6.4.5] +/// " [s-char-sequence] " +/// L" [s-char-sequence] " +/// s-char-sequence: +/// s-char +/// s-char-sequence s-char +/// s-char: +/// any source character except the double quote ", +/// backslash \, or newline character +/// escape-character +/// universal-character-name +/// escape-character: [C99 6.4.4.4] +/// \ escape-code +/// universal-character-name +/// escape-code: +/// character-escape-code +/// octal-escape-code +/// hex-escape-code +/// character-escape-code: one of +/// n t b r f v a +/// \ ' " ? +/// octal-escape-code: +/// octal-digit +/// octal-digit octal-digit +/// octal-digit octal-digit octal-digit +/// hex-escape-code: +/// x hex-digit +/// hex-escape-code hex-digit +/// universal-character-name: +/// \u hex-quad +/// \U hex-quad hex-quad +/// hex-quad: +/// hex-digit hex-digit hex-digit hex-digit +/// +StringLiteralParser:: +StringLiteralParser(const Token *StringToks, unsigned NumStringToks, + Preprocessor &pp) : PP(pp) { + // Scan all of the string portions, remember the max individual token length, + // computing a bound on the concatenated string length, and see whether any + // piece is a wide-string. If any of the string portions is a wide-string + // literal, the result is a wide-string literal [C99 6.4.5p4]. + MaxTokenLength = StringToks[0].getLength(); + SizeBound = StringToks[0].getLength()-2; // -2 for "". + AnyWide = StringToks[0].is(tok::wide_string_literal); + + hadError = false; + + // Implement Translation Phase #6: concatenation of string literals + /// (C99 5.1.1.2p1). The common case is only one string fragment. + for (unsigned i = 1; i != NumStringToks; ++i) { + // The string could be shorter than this if it needs cleaning, but this is a + // reasonable bound, which is all we need. + SizeBound += StringToks[i].getLength()-2; // -2 for "". + + // Remember maximum string piece length. + if (StringToks[i].getLength() > MaxTokenLength) + MaxTokenLength = StringToks[i].getLength(); + + // Remember if we see any wide strings. + AnyWide |= StringToks[i].is(tok::wide_string_literal); + } + + // Include space for the null terminator. + ++SizeBound; + + // TODO: K&R warning: "traditional C rejects string constant concatenation" + + // Get the width in bytes of wchar_t. If no wchar_t strings are used, do not + // query the target. As such, wchar_tByteWidth is only valid if AnyWide=true. + wchar_tByteWidth = ~0U; + if (AnyWide) { + wchar_tByteWidth = PP.getTargetInfo().getWCharWidth(); + assert((wchar_tByteWidth & 7) == 0 && "Assumes wchar_t is byte multiple!"); + wchar_tByteWidth /= 8; + } + + // The output buffer size needs to be large enough to hold wide characters. + // This is a worst-case assumption which basically corresponds to L"" "long". + if (AnyWide) + SizeBound *= wchar_tByteWidth; + + // Size the temporary buffer to hold the result string data. + ResultBuf.resize(SizeBound); + + // Likewise, but for each string piece. + llvm::SmallString<512> TokenBuf; + TokenBuf.resize(MaxTokenLength); + + // Loop over all the strings, getting their spelling, and expanding them to + // wide strings as appropriate. + ResultPtr = &ResultBuf[0]; // Next byte to fill in. + + Pascal = false; + + for (unsigned i = 0, e = NumStringToks; i != e; ++i) { + const char *ThisTokBuf = &TokenBuf[0]; + // Get the spelling of the token, which eliminates trigraphs, etc. We know + // that ThisTokBuf points to a buffer that is big enough for the whole token + // and 'spelled' tokens can only shrink. + unsigned ThisTokLen = PP.getSpelling(StringToks[i], ThisTokBuf); + const char *ThisTokEnd = ThisTokBuf+ThisTokLen-1; // Skip end quote. + + // TODO: Input character set mapping support. + + // Skip L marker for wide strings. + bool ThisIsWide = false; + if (ThisTokBuf[0] == 'L') { + ++ThisTokBuf; + ThisIsWide = true; + } + + assert(ThisTokBuf[0] == '"' && "Expected quote, lexer broken?"); + ++ThisTokBuf; + + // Check if this is a pascal string + if (pp.getLangOptions().PascalStrings && ThisTokBuf + 1 != ThisTokEnd && + ThisTokBuf[0] == '\\' && ThisTokBuf[1] == 'p') { + + // If the \p sequence is found in the first token, we have a pascal string + // Otherwise, if we already have a pascal string, ignore the first \p + if (i == 0) { + ++ThisTokBuf; + Pascal = true; + } else if (Pascal) + ThisTokBuf += 2; + } + + while (ThisTokBuf != ThisTokEnd) { + // Is this a span of non-escape characters? + if (ThisTokBuf[0] != '\\') { + const char *InStart = ThisTokBuf; + do { + ++ThisTokBuf; + } while (ThisTokBuf != ThisTokEnd && ThisTokBuf[0] != '\\'); + + // Copy the character span over. + unsigned Len = ThisTokBuf-InStart; + if (!AnyWide) { + memcpy(ResultPtr, InStart, Len); + ResultPtr += Len; + } else { + // Note: our internal rep of wide char tokens is always little-endian. + for (; Len; --Len, ++InStart) { + *ResultPtr++ = InStart[0]; + // Add zeros at the end. + for (unsigned i = 1, e = wchar_tByteWidth; i != e; ++i) + *ResultPtr++ = 0; + } + } + continue; + } + // Is this a Universal Character Name escape? + if (ThisTokBuf[1] == 'u' || ThisTokBuf[1] == 'U') { + ProcessUCNEscape(ThisTokBuf, ThisTokEnd, ResultPtr, + hadError, StringToks[i].getLocation(), ThisIsWide, PP); + continue; + } + // Otherwise, this is a non-UCN escape character. Process it. + unsigned ResultChar = ProcessCharEscape(ThisTokBuf, ThisTokEnd, hadError, + StringToks[i].getLocation(), + ThisIsWide, PP); + + // Note: our internal rep of wide char tokens is always little-endian. + *ResultPtr++ = ResultChar & 0xFF; + + if (AnyWide) { + for (unsigned i = 1, e = wchar_tByteWidth; i != e; ++i) + *ResultPtr++ = ResultChar >> i*8; + } + } + } + + if (Pascal) { + ResultBuf[0] = ResultPtr-&ResultBuf[0]-1; + + // Verify that pascal strings aren't too large. + if (GetStringLength() > 256) { + PP.Diag(StringToks[0].getLocation(), diag::err_pascal_string_too_long) + << SourceRange(StringToks[0].getLocation(), + StringToks[NumStringToks-1].getLocation()); + hadError = 1; + return; + } + } +} + + +/// getOffsetOfStringByte - This function returns the offset of the +/// specified byte of the string data represented by Token. This handles +/// advancing over escape sequences in the string. +unsigned StringLiteralParser::getOffsetOfStringByte(const Token &Tok, + unsigned ByteNo, + Preprocessor &PP) { + // Get the spelling of the token. + llvm::SmallString<16> SpellingBuffer; + SpellingBuffer.resize(Tok.getLength()); + + const char *SpellingPtr = &SpellingBuffer[0]; + unsigned TokLen = PP.getSpelling(Tok, SpellingPtr); + + assert(SpellingPtr[0] != 'L' && "Doesn't handle wide strings yet"); + + + const char *SpellingStart = SpellingPtr; + const char *SpellingEnd = SpellingPtr+TokLen; + + // Skip over the leading quote. + assert(SpellingPtr[0] == '"' && "Should be a string literal!"); + ++SpellingPtr; + + // Skip over bytes until we find the offset we're looking for. + while (ByteNo) { + assert(SpellingPtr < SpellingEnd && "Didn't find byte offset!"); + + // Step over non-escapes simply. + if (*SpellingPtr != '\\') { + ++SpellingPtr; + --ByteNo; + continue; + } + + // Otherwise, this is an escape character. Advance over it. + bool HadError = false; + ProcessCharEscape(SpellingPtr, SpellingEnd, HadError, + Tok.getLocation(), false, PP); + assert(!HadError && "This method isn't valid on erroneous strings"); + --ByteNo; + } + + return SpellingPtr-SpellingStart; +} |
