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llvm-project/clang/lib/Lex/LiteralSupport.cpp

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//===--- 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.
if (!PP.getLangOptions().NoExtensions) {
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;
Value = 0;
// 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: This assumes that 'int' is 32-bits in overflow calculation, and the
// size of "value".
assert(PP.getTargetInfo().getIntWidth() == 32 &&
"Assumes sizeof(int) == 4 for now");
// FIXME: This assumes that wchar_t is 32-bits for now.
assert(PP.getTargetInfo().getWCharWidth() == 32 &&
"Assumes sizeof(wchar_t) == 4 for now");
// FIXME: This extensively assumes that 'char' is 8-bits.
assert(PP.getTargetInfo().getCharWidth() == 8 &&
"Assumes char is 8 bits");
bool isFirstChar = true;
bool isMultiChar = false;
while (begin[0] != '\'') {
unsigned 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 (!isFirstChar) {
// If this is the second character being processed, do special handling.
if (!isMultiChar) {
isMultiChar = true;
// 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);
}
if (IsWide) {
// Emulate GCC's (unintentional?) behavior: L'ab' -> L'b'.
Value = 0;
} else {
// Narrow character literals act as though their value is concatenated
// in this implementation.
if (((Value << 8) >> 8) != Value)
PP.Diag(Loc, diag::warn_char_constant_too_large);
Value <<= 8;
}
}
Value += ResultChar;
isFirstChar = false;
}
// 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 && !isMultiChar && (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;
}
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