1 /* Parse C expressions for cpplib.
2 Copyright (C) 1987, 1992, 1994, 1995, 1997, 1998, 1999, 2000, 2001
3 Free Software Foundation.
4 Contributed by Per Bothner, 1994.
6 This program is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /* Parse a C expression from text in a string */
28 #ifndef MAX_CHAR_TYPE_SIZE
29 #define MAX_CHAR_TYPE_SIZE CHAR_TYPE_SIZE
32 #ifndef MAX_INT_TYPE_SIZE
33 #define MAX_INT_TYPE_SIZE INT_TYPE_SIZE
36 #ifndef MAX_LONG_TYPE_SIZE
37 #define MAX_LONG_TYPE_SIZE LONG_TYPE_SIZE
40 #ifndef MAX_WCHAR_TYPE_SIZE
41 #define MAX_WCHAR_TYPE_SIZE WCHAR_TYPE_SIZE
44 #define MAX_CHAR_TYPE_MASK (MAX_CHAR_TYPE_SIZE < HOST_BITS_PER_WIDEST_INT \
45 ? (~(~(HOST_WIDEST_INT) 0 << MAX_CHAR_TYPE_SIZE)) \
46 : ~ (HOST_WIDEST_INT) 0)
48 #define MAX_WCHAR_TYPE_MASK (MAX_WCHAR_TYPE_SIZE < HOST_BITS_PER_WIDEST_INT \
49 ? ~(~(HOST_WIDEST_INT) 0 << MAX_WCHAR_TYPE_SIZE) \
50 : ~ (HOST_WIDEST_INT) 0)
52 /* Yield nonzero if adding two numbers with A's and B's signs can yield a
53 number with SUM's sign, where A, B, and SUM are all C integers. */
54 #define possible_sum_sign(a, b, sum) ((((a) ^ (b)) | ~ ((a) ^ (sum))) < 0)
56 static void integer_overflow PARAMS ((cpp_reader *));
57 static HOST_WIDEST_INT left_shift PARAMS ((cpp_reader *, HOST_WIDEST_INT,
59 unsigned HOST_WIDEST_INT));
60 static HOST_WIDEST_INT right_shift PARAMS ((cpp_reader *, HOST_WIDEST_INT,
62 unsigned HOST_WIDEST_INT));
63 static struct op parse_number PARAMS ((cpp_reader *, const cpp_token *));
64 static struct op parse_charconst PARAMS ((cpp_reader *, const cpp_token *));
65 static struct op parse_defined PARAMS ((cpp_reader *));
66 static HOST_WIDEST_INT parse_escape PARAMS ((cpp_reader *, const U_CHAR **,
67 const U_CHAR *, HOST_WIDEST_INT));
68 static struct op lex PARAMS ((cpp_reader *, int, cpp_token *));
69 static const unsigned char *op_as_text PARAMS ((cpp_reader *, enum cpp_ttype));
74 U_CHAR prio; /* Priority of op. */
76 U_CHAR unsignedp; /* True if value should be treated as unsigned. */
77 HOST_WIDEST_INT value; /* The value logically "right" of op. */
80 /* There is no "error" token, but we can't get comments in #if, so we can
81 abuse that token type. */
82 #define CPP_ERROR CPP_COMMENT
84 /* With -O2, gcc appears to produce nice code, moving the error
85 message load and subsequent jump completely out of the main path. */
86 #define CPP_ICE(msgid) \
87 do { cpp_ice (pfile, msgid); goto syntax_error; } while(0)
88 #define SYNTAX_ERROR(msgid) \
89 do { cpp_error (pfile, msgid); goto syntax_error; } while(0)
90 #define SYNTAX_ERROR2(msgid, arg) \
91 do { cpp_error (pfile, msgid, arg); goto syntax_error; } while(0)
93 /* Parse and convert an integer for #if. Accepts decimal, hex, or octal
94 with or without size suffixes. */
102 const struct suffix vsuf_1[] = {
103 { "u", 1, 0 }, { "U", 1, 0 },
104 { "l", 0, 1 }, { "L", 0, 1 }
107 const struct suffix vsuf_2[] = {
108 { "ul", 1, 1 }, { "UL", 1, 1 }, { "uL", 1, 1 }, { "Ul", 1, 1 },
109 { "lu", 1, 1 }, { "LU", 1, 1 }, { "Lu", 1, 1 }, { "lU", 1, 1 },
110 { "ll", 0, 2 }, { "LL", 0, 2 }
113 const struct suffix vsuf_3[] = {
114 { "ull", 1, 2 }, { "ULL", 1, 2 }, { "uLL", 1, 2 }, { "Ull", 1, 2 },
115 { "llu", 1, 2 }, { "LLU", 1, 2 }, { "LLu", 1, 2 }, { "llU", 1, 2 }
117 #define Nsuff(tab) (sizeof tab / sizeof (struct suffix))
120 parse_number (pfile, tok)
122 const cpp_token *tok;
125 const U_CHAR *start = tok->val.str.text;
126 const U_CHAR *end = start + tok->val.str.len;
127 const U_CHAR *p = start;
129 unsigned HOST_WIDEST_INT n = 0, nd, MAX_over_base;
132 int digit, largest_digit = 0;
133 const struct suffix *sufftab;
139 if (end - start >= 3 && (p[1] == 'x' || p[1] == 'X'))
151 /* Some buggy compilers (e.g. MPW C) seem to need both casts. */
152 MAX_over_base = (((unsigned HOST_WIDEST_INT) -1)
153 / ((unsigned HOST_WIDEST_INT) base));
159 if (c >= '0' && c <= '9')
161 /* We believe that in all live character sets, a-f are
162 consecutive, and so are A-F. */
163 else if (base == 16 && c >= 'a' && c <= 'f')
164 digit = c - 'a' + 10;
165 else if (base == 16 && c >= 'A' && c <= 'F')
166 digit = c - 'A' + 10;
170 if (largest_digit < digit)
171 largest_digit = digit;
172 nd = n * base + digit;
173 overflow |= MAX_over_base < n || nd < n;
179 /* Check for a floating point constant. Note that float constants
180 with an exponent or suffix but no decimal point are technically
181 invalid (C99 6.4.4.2) but accepted elsewhere. */
182 if ((c == '.' || c == 'F' || c == 'f')
183 || (base == 10 && (c == 'E' || c == 'e')
184 && p+1 < end && (p[1] == '+' || p[1] == '-'))
185 || (base == 16 && (c == 'P' || c == 'p')
186 && p+1 < end && (p[1] == '+' || p[1] == '-')))
187 SYNTAX_ERROR ("floating point numbers are not valid in #if");
189 /* Determine the suffix. l means long, and u means unsigned.
190 See the suffix tables, above. */
193 case 1: sufftab = vsuf_1; nsuff = Nsuff(vsuf_1); break;
194 case 2: sufftab = vsuf_2; nsuff = Nsuff(vsuf_2); break;
195 case 3: sufftab = vsuf_3; nsuff = Nsuff(vsuf_3); break;
196 default: goto invalid_suffix;
199 for (i = 0; i < nsuff; i++)
200 if (memcmp (p, sufftab[i].s, end - p) == 0)
204 op.unsignedp = sufftab[i].u;
206 if (CPP_WTRADITIONAL (pfile) && sufftab[i].u)
207 cpp_warning (pfile, "traditional C rejects the `U' suffix");
208 if (sufftab[i].l == 2 && CPP_OPTION (pfile, pedantic)
209 && ! CPP_OPTION (pfile, c99))
210 cpp_pedwarn (pfile, "too many 'l' suffixes in integer constant");
213 if (base <= largest_digit)
214 cpp_pedwarn (pfile, "integer constant contains digits beyond the radix");
217 cpp_pedwarn (pfile, "integer constant out of range");
219 /* If too big to be signed, consider it unsigned. */
220 else if ((HOST_WIDEST_INT) n < 0 && ! op.unsignedp)
223 cpp_warning (pfile, "integer constant is so large that it is unsigned");
232 cpp_error (pfile, "invalid suffix '%.*s' on integer constant",
239 /* Parse and convert a character constant for #if. Understands backslash
240 escapes (\n, \031) and multibyte characters (if so configured). */
242 parse_charconst (pfile, tok)
244 const cpp_token *tok;
247 HOST_WIDEST_INT result = 0;
250 unsigned int width = MAX_CHAR_TYPE_SIZE;
251 HOST_WIDEST_INT mask = MAX_CHAR_TYPE_MASK;
253 const U_CHAR *ptr = tok->val.str.text;
254 const U_CHAR *end = ptr + tok->val.str.len;
258 if (tok->type == CPP_WCHAR)
259 width = MAX_WCHAR_TYPE_SIZE, mask = MAX_WCHAR_TYPE_MASK;
260 max_chars = MAX_LONG_TYPE_SIZE / width;
266 CPP_ICE ("unescaped ' in character constant");
269 c = parse_escape (pfile, &ptr, end, mask);
270 if (width < HOST_BITS_PER_INT
271 && (unsigned int) c >= (unsigned int)(1 << width))
273 "escape sequence out of range for character");
276 /* Merge character into result; ignore excess chars. */
277 if (++num_chars <= max_chars)
279 if (width < HOST_BITS_PER_INT)
280 result = (result << width) | (c & ((1 << width) - 1));
287 SYNTAX_ERROR ("empty character constant");
288 else if (num_chars > max_chars)
289 SYNTAX_ERROR ("character constant too long");
290 else if (num_chars != 1)
291 cpp_warning (pfile, "multi-character character constant");
293 /* If char type is signed, sign-extend the constant. */
294 num_bits = num_chars * width;
296 if (pfile->spec_nodes.n__CHAR_UNSIGNED__->type == NT_MACRO
297 || ((result >> (num_bits - 1)) & 1) == 0)
298 op.value = result & ((unsigned HOST_WIDEST_INT) ~0
299 >> (HOST_BITS_PER_WIDEST_INT - num_bits));
301 op.value = result | ~((unsigned HOST_WIDEST_INT) ~0
302 >> (HOST_BITS_PER_WIDEST_INT - num_bits));
304 /* This is always a signed type. */
315 parse_defined (pfile)
319 cpp_hashnode *node = 0;
323 /* Don't expand macros. */
324 pfile->state.prevent_expansion++;
326 cpp_get_token (pfile, &token);
327 if (token.type == CPP_OPEN_PAREN)
330 cpp_get_token (pfile, &token);
333 if (token.type == CPP_NAME)
335 node = token.val.node;
338 cpp_get_token (pfile, &token);
339 if (token.type != CPP_CLOSE_PAREN)
341 cpp_error (pfile, "missing ')' after \"defined\"");
348 cpp_error (pfile, "operator \"defined\" requires an identifier");
349 if (token.flags & NAMED_OP)
354 op.type = token.type;
356 "(\"%s\" is an alternative token for \"%s\" in C++)",
357 cpp_token_as_text (pfile, &token),
358 cpp_token_as_text (pfile, &op));
366 op.value = node->type == NT_MACRO;
370 /* No macros? At top of file? */
371 if (pfile->mi_state == MI_OUTSIDE && pfile->mi_cmacro == 0
372 && pfile->mi_if_not_defined == MI_IND_NOT && pfile->mi_lexed == 1)
374 cpp_start_lookahead (pfile);
375 cpp_get_token (pfile, &token);
376 if (token.type == CPP_EOF)
377 pfile->mi_ind_cmacro = node;
378 cpp_stop_lookahead (pfile, 0);
382 pfile->state.prevent_expansion--;
386 /* Read one token. */
389 lex (pfile, skip_evaluation, token)
396 cpp_get_token (pfile, token);
402 return parse_number (pfile, token);
406 return parse_charconst (pfile, token);
410 SYNTAX_ERROR ("string constants are not valid in #if");
413 SYNTAX_ERROR ("floating point numbers are not valid in #if");
416 if (ISGRAPH (token->val.c))
417 SYNTAX_ERROR2 ("invalid character '%c' in #if", token->val.c);
419 SYNTAX_ERROR2 ("invalid character '\\%03o' in #if", token->val.c);
422 if (token->val.node == pfile->spec_nodes.n_defined)
424 if (pfile->context->prev && CPP_PEDANTIC (pfile))
425 cpp_pedwarn (pfile, "\"defined\" operator appears during macro expansion");
427 return parse_defined (pfile);
429 else if (CPP_OPTION (pfile, cplusplus)
430 && (token->val.node == pfile->spec_nodes.n_true
431 || token->val.node == pfile->spec_nodes.n_false))
435 op.value = (token->val.node == pfile->spec_nodes.n_true);
437 /* Warn about use of true or false in #if when pedantic
438 and stdbool.h has not been included. */
439 if (CPP_PEDANTIC (pfile)
440 && ! cpp_defined (pfile, DSC("__bool_true_false_are_defined")))
441 cpp_pedwarn (pfile, "ISO C++ does not permit \"%s\" in #if",
442 token->val.node->name);
447 /* Controlling #if expressions cannot contain identifiers (they
448 could become macros in the future). */
449 pfile->mi_state = MI_FAILED;
455 if (CPP_OPTION (pfile, warn_undef) && !skip_evaluation)
456 cpp_warning (pfile, "\"%s\" is not defined", token->val.node->name);
465 if (_cpp_test_assertion (pfile, &temp))
473 /* We don't worry about its position here. */
474 pfile->mi_if_not_defined = MI_IND_NOT;
478 if ((token->type > CPP_EQ && token->type < CPP_PLUS_EQ)
479 || token->type == CPP_EOF)
485 SYNTAX_ERROR2 ("\"%s\" is not valid in #if expressions",
486 cpp_token_as_text (pfile, token));
494 /* Parse a C escape sequence. STRING_PTR points to a variable
495 containing a pointer to the string to parse. That pointer
496 is updated past the characters we use. The value of the
497 escape sequence is returned.
499 If \ is followed by 000, we return 0 and leave the string pointer
500 after the zeros. A value of 0 does not mean end of string. */
502 static HOST_WIDEST_INT
503 parse_escape (pfile, string_ptr, limit, result_mask)
505 const U_CHAR **string_ptr;
507 HOST_WIDEST_INT result_mask;
509 const U_CHAR *ptr = *string_ptr;
510 /* We know we have at least one following character. */
514 case 'a': c = TARGET_BELL; break;
515 case 'b': c = TARGET_BS; break;
516 case 'f': c = TARGET_FF; break;
517 case 'n': c = TARGET_NEWLINE; break;
518 case 'r': c = TARGET_CR; break;
519 case 't': c = TARGET_TAB; break;
520 case 'v': c = TARGET_VT; break;
523 if (CPP_PEDANTIC (pfile))
524 cpp_pedwarn (pfile, "non-ISO-standard escape sequence, '\\%c'", c);
528 case '0': case '1': case '2': case '3':
529 case '4': case '5': case '6': case '7':
531 unsigned int i = c - '0';
539 if (c < '0' || c > '7')
542 i = (i << 3) + c - '0';
544 if (i != (i & result_mask))
547 cpp_pedwarn (pfile, "octal escape sequence out of range");
555 unsigned int i = 0, overflow = 0;
556 int digits_found = 0, digit;
562 if (c >= '0' && c <= '9')
564 else if (c >= 'a' && c <= 'f')
565 digit = c - 'a' + 10;
566 else if (c >= 'A' && c <= 'F')
567 digit = c - 'A' + 10;
571 overflow |= i ^ (i << 4 >> 4);
572 i = (i << 4) + digit;
576 cpp_error (pfile, "\\x used with no following hex digits");
577 if (overflow | (i != (i & result_mask)))
580 cpp_pedwarn (pfile, "hex escape sequence out of range");
591 integer_overflow (pfile)
594 if (CPP_PEDANTIC (pfile))
595 cpp_pedwarn (pfile, "integer overflow in preprocessor expression");
598 static HOST_WIDEST_INT
599 left_shift (pfile, a, unsignedp, b)
602 unsigned int unsignedp;
603 unsigned HOST_WIDEST_INT b;
605 if (b >= HOST_BITS_PER_WIDEST_INT)
607 if (! unsignedp && a != 0)
608 integer_overflow (pfile);
612 return (unsigned HOST_WIDEST_INT) a << b;
615 HOST_WIDEST_INT l = a << b;
617 integer_overflow (pfile);
622 static HOST_WIDEST_INT
623 right_shift (pfile, a, unsignedp, b)
624 cpp_reader *pfile ATTRIBUTE_UNUSED;
626 unsigned int unsignedp;
627 unsigned HOST_WIDEST_INT b;
629 if (b >= HOST_BITS_PER_WIDEST_INT)
630 return unsignedp ? 0 : a >> (HOST_BITS_PER_WIDEST_INT - 1);
632 return (unsigned HOST_WIDEST_INT) a >> b;
637 /* Operator precedence and flags table.
639 After an operator is returned from the lexer, if it has priority less
640 than or equal to the operator on the top of the stack, we reduce the
641 stack by one operator and repeat the test. Since equal priorities
642 reduce, this is naturally left-associative.
644 We handle right-associative operators by clearing the lower bit of all
645 left-associative operators, and setting it for right-associative ones.
646 After the reduction phase of a new operator, just before it is pushed
647 onto the stack, its RIGHT_ASSOC bit is cleared. The effect is that
648 during the reduction phase, the current right-associative operator has
649 a priority one greater than any other operator of otherwise equal
650 precedence that has been pushed on the top of the stack. This avoids
651 a reduction pass, and effectively makes the logic right-associative.
653 The remaining cases are '(' and ')'. We handle '(' by skipping the
654 reduction phase completely. ')' is given lower priority than
655 everything else, including '(', effectively forcing a reduction of the
656 parenthesised expression. If there is no matching '(', the stack will
657 be reduced all the way to the beginning, exiting the parser in the
658 same way as the ultra-low priority end-of-expression dummy operator.
659 The exit code checks to see if the operator that caused it is ')', and
660 if so outputs an appropriate error message.
662 The parser assumes all shifted operators require a right operand
663 unless the flag NO_R_OPERAND is set, and similarly for NO_L_OPERAND.
664 These semantics are automatically checked, any extra semantics need to
665 be handled with operator-specific code. */
668 #define FLAG_MASK ((1 << FLAG_BITS) - 1)
669 #define PRIO_SHIFT (FLAG_BITS + 1)
670 #define EXTRACT_PRIO(cnst) (cnst >> FLAG_BITS)
671 #define EXTRACT_FLAGS(cnst) (cnst & FLAG_MASK)
674 #define HAVE_VALUE (1 << 0)
675 #define NO_L_OPERAND (1 << 1)
676 #define NO_R_OPERAND (1 << 2)
677 #define SHORT_CIRCUIT (1 << 3)
679 /* Priority and flag combinations. */
680 #define RIGHT_ASSOC (1 << FLAG_BITS)
681 #define FORCE_REDUCE_PRIO (0 << PRIO_SHIFT)
682 #define CLOSE_PAREN_PRIO (1 << PRIO_SHIFT)
683 #define OPEN_PAREN_PRIO ((2 << PRIO_SHIFT) | NO_L_OPERAND)
684 #define COMMA_PRIO (3 << PRIO_SHIFT)
685 #define COND_PRIO ((4 << PRIO_SHIFT) | RIGHT_ASSOC | SHORT_CIRCUIT)
686 #define COLON_PRIO ((5 << PRIO_SHIFT) | SHORT_CIRCUIT)
687 #define OROR_PRIO ((6 << PRIO_SHIFT) | SHORT_CIRCUIT)
688 #define ANDAND_PRIO ((7 << PRIO_SHIFT) | SHORT_CIRCUIT)
689 #define OR_PRIO (8 << PRIO_SHIFT)
690 #define XOR_PRIO (9 << PRIO_SHIFT)
691 #define AND_PRIO (10 << PRIO_SHIFT)
692 #define MINMAX_PRIO (11 << PRIO_SHIFT)
693 #define EQUAL_PRIO (12 << PRIO_SHIFT)
694 #define LESS_PRIO (13 << PRIO_SHIFT)
695 #define SHIFT_PRIO (14 << PRIO_SHIFT)
696 #define PLUS_PRIO (15 << PRIO_SHIFT)
697 #define MUL_PRIO (16 << PRIO_SHIFT)
698 #define UNARY_PRIO ((17 << PRIO_SHIFT) | RIGHT_ASSOC | NO_L_OPERAND)
700 /* Operator to priority map. Must be in the same order as the first
701 N entries of enum cpp_ttype. */
705 /* EQ */ 0, /* dummy entry - can't happen */
706 /* NOT */ UNARY_PRIO,
707 /* GREATER */ LESS_PRIO,
708 /* LESS */ LESS_PRIO,
709 /* PLUS */ UNARY_PRIO, /* note these two can be unary */
710 /* MINUS */ UNARY_PRIO, /* or binary */
717 /* RSHIFT */ SHIFT_PRIO,
718 /* LSHIFT */ SHIFT_PRIO,
719 /* MIN */ MINMAX_PRIO, /* C++ specific */
720 /* MAX */ MINMAX_PRIO, /* extensions */
722 /* COMPL */ UNARY_PRIO,
723 /* AND_AND */ ANDAND_PRIO,
724 /* OR_OR */ OROR_PRIO,
725 /* QUERY */ COND_PRIO,
726 /* COLON */ COLON_PRIO,
727 /* COMMA */ COMMA_PRIO,
728 /* OPEN_PAREN */ OPEN_PAREN_PRIO,
729 /* CLOSE_PAREN */ CLOSE_PAREN_PRIO,
730 /* EQ_EQ */ EQUAL_PRIO,
731 /* NOT_EQ */ EQUAL_PRIO,
732 /* GREATER_EQ */ LESS_PRIO,
733 /* LESS_EQ */ LESS_PRIO
736 #define COMPARE(OP) \
737 top->unsignedp = 0; \
738 top->value = (unsigned1 | unsigned2) \
739 ? (unsigned HOST_WIDEST_INT) v1 OP (unsigned HOST_WIDEST_INT) v2 \
741 #define EQUALITY(OP) \
742 top->value = v1 OP v2; \
744 #define BITWISE(OP) \
745 top->value = v1 OP v2; \
746 top->unsignedp = unsigned1 | unsigned2;
748 top->value = (v1 OP v2) ? v1 : v2; \
749 top->unsignedp = unsigned1 | unsigned2;
751 top->value = OP v2; \
752 top->unsignedp = unsigned2; \
753 top->flags |= HAVE_VALUE;
754 #define SHIFT(PSH, MSH) \
755 if (skip_evaluation) \
757 top->unsignedp = unsigned1; \
758 if (v2 < 0 && ! unsigned2) \
759 top->value = MSH (pfile, v1, unsigned1, -v2); \
761 top->value = PSH (pfile, v1, unsigned1, v2);
763 /* Parse and evaluate a C expression, reading from PFILE.
764 Returns the truth value of the expression. */
767 _cpp_parse_expr (pfile)
770 /* The implementation is an operator precedence parser, i.e. a
771 bottom-up parser, using a stack for not-yet-reduced tokens.
773 The stack base is 'stack', and the current stack pointer is 'top'.
774 There is a stack element for each operator (only),
775 and the most recently pushed operator is 'top->op'.
776 An operand (value) is stored in the 'value' field of the stack
777 element of the operator that precedes it.
778 In that case the 'flags' field has the HAVE_VALUE flag set. */
780 #define INIT_STACK_SIZE 20
781 struct op init_stack[INIT_STACK_SIZE];
782 struct op *stack = init_stack;
783 struct op *limit = stack + INIT_STACK_SIZE;
785 register struct op *top = stack + 1;
786 int skip_evaluation = 0;
789 /* Set up detection of #if ! defined(). */
791 pfile->mi_if_not_defined = MI_IND_NONE;
793 /* We've finished when we try to reduce this. */
795 /* Nifty way to catch missing '('. */
796 top->prio = EXTRACT_PRIO(CLOSE_PAREN_PRIO);
797 /* Avoid missing right operand checks. */
798 top->flags = NO_R_OPERAND;
807 op = lex (pfile, skip_evaluation, &token);
810 /* If the token is an operand, push its value and get next
811 token. If it is an operator, get its priority and flags, and
812 try to reduce the expression on the stack. */
819 /* Push a value onto the stack. */
820 if (top->flags & HAVE_VALUE)
821 SYNTAX_ERROR ("missing binary operator");
822 top->value = op.value;
823 top->unsignedp = op.unsignedp;
824 top->flags |= HAVE_VALUE;
827 case CPP_EOF: prio = FORCE_REDUCE_PRIO; break;
829 case CPP_MINUS: prio = PLUS_PRIO; if (top->flags & HAVE_VALUE) break;
830 /* else unary; fall through */
831 default: prio = op_to_prio[op.op]; break;
834 /* Separate the operator's code into priority and flags. */
835 flags = EXTRACT_FLAGS(prio);
836 prio = EXTRACT_PRIO(prio);
837 if (prio == EXTRACT_PRIO(OPEN_PAREN_PRIO))
840 /* Check for reductions. Then push the operator. */
841 while (prio <= top->prio)
843 HOST_WIDEST_INT v1, v2;
844 unsigned int unsigned1, unsigned2;
846 /* Most operators that can appear on the stack require a
847 right operand. Check this before trying to reduce. */
848 if ((top->flags & (HAVE_VALUE | NO_R_OPERAND)) == 0)
850 if (top->op == CPP_OPEN_PAREN)
851 SYNTAX_ERROR ("void expression between '(' and ')'");
853 SYNTAX_ERROR2 ("operator '%s' has no right operand",
854 op_as_text (pfile, top->op));
857 unsigned2 = top->unsignedp, v2 = top->value;
859 unsigned1 = top->unsignedp, v1 = top->value;
861 /* Now set top->value = (top[1].op)(v1, v2); */
865 cpp_ice (pfile, "impossible operator '%s'",
866 op_as_text (pfile, top[1].op));
869 case CPP_NOT: UNARY(!); break;
870 case CPP_COMPL: UNARY(~); break;
871 case CPP_LESS: COMPARE(<); break;
872 case CPP_GREATER: COMPARE(>); break;
873 case CPP_LESS_EQ: COMPARE(<=); break;
874 case CPP_GREATER_EQ: COMPARE(>=); break;
875 case CPP_EQ_EQ: EQUALITY(==); break;
876 case CPP_NOT_EQ: EQUALITY(!=); break;
877 case CPP_AND: BITWISE(&); break;
878 case CPP_XOR: BITWISE(^); break;
879 case CPP_OR: BITWISE(|); break;
880 case CPP_LSHIFT: SHIFT(left_shift, right_shift); break;
881 case CPP_RSHIFT: SHIFT(right_shift, left_shift); break;
882 case CPP_MIN: MINMAX(<); break;
883 case CPP_MAX: MINMAX(>); break;
886 if (!(top->flags & HAVE_VALUE))
888 /* Can't use UNARY(+) because K+R C did not have unary
889 plus. Can't use UNARY() because some compilers object
890 to the empty argument. */
892 top->unsignedp = unsigned2;
893 top->flags |= HAVE_VALUE;
895 if (CPP_WTRADITIONAL (pfile))
897 "traditional C rejects the unary plus operator");
901 top->value = v1 + v2;
902 top->unsignedp = unsigned1 | unsigned2;
903 if (! top->unsignedp && ! skip_evaluation
904 && ! possible_sum_sign (v1, v2, top->value))
905 integer_overflow (pfile);
909 if (!(top->flags & HAVE_VALUE))
912 if (!skip_evaluation && (top->value & v2) < 0 && !unsigned2)
913 integer_overflow (pfile);
917 top->value = v1 - v2;
918 top->unsignedp = unsigned1 | unsigned2;
919 if (! top->unsignedp && ! skip_evaluation
920 && ! possible_sum_sign (top->value, v2, v1))
921 integer_overflow (pfile);
925 top->unsignedp = unsigned1 | unsigned2;
927 top->value = (unsigned HOST_WIDEST_INT) v1 * v2;
928 else if (!skip_evaluation)
930 top->value = v1 * v2;
931 if (v1 && (top->value / v1 != v2
932 || (top->value & v1 & v2) < 0))
933 integer_overflow (pfile);
941 SYNTAX_ERROR ("division by zero in #if");
942 top->unsignedp = unsigned1 | unsigned2;
943 if (top[1].op == CPP_DIV)
946 top->value = (unsigned HOST_WIDEST_INT) v1 / v2;
949 top->value = v1 / v2;
950 if ((top->value & v1 & v2) < 0)
951 integer_overflow (pfile);
957 top->value = (unsigned HOST_WIDEST_INT) v1 % v2;
959 top->value = v1 % v2;
964 top->value = v1 || v2;
966 if (v1) skip_evaluation--;
969 top->value = v1 && v2;
971 if (!v1) skip_evaluation--;
974 if (CPP_PEDANTIC (pfile))
975 cpp_pedwarn (pfile, "comma operator in operand of #if");
977 top->unsignedp = unsigned2;
980 SYNTAX_ERROR ("syntax error '?' without following ':'");
982 if (top[0].op != CPP_QUERY)
983 SYNTAX_ERROR ("syntax error ':' without preceding '?'");
985 if (top->value) skip_evaluation--;
986 top->value = top->value ? v1 : v2;
987 top->unsignedp = unsigned1 | unsigned2;
990 if (op.op != CPP_CLOSE_PAREN)
991 SYNTAX_ERROR ("missing ')' in expression");
993 op.unsignedp = unsigned2;
996 /* Reducing this dummy operator indicates we've finished. */
997 if (op.op == CPP_CLOSE_PAREN)
998 SYNTAX_ERROR ("missing '(' in expression");
1003 /* Handle short-circuit evaluations. */
1004 if (flags & SHORT_CIRCUIT)
1007 case CPP_OR_OR: if (top->value) skip_evaluation++; break;
1009 case CPP_QUERY: if (!top->value) skip_evaluation++; break;
1011 if (top[-1].value) /* Was '?' condition true? */
1020 /* Check we have a left operand iff we need one. */
1021 if (flags & NO_L_OPERAND)
1023 if (top->flags & HAVE_VALUE)
1024 SYNTAX_ERROR2 ("missing binary operator before '%s'",
1025 op_as_text (pfile, top->op));
1029 if (!(top->flags & HAVE_VALUE))
1030 SYNTAX_ERROR2 ("operator '%s' has no left operand",
1031 op_as_text (pfile, top->op));
1034 /* Check for and handle stack overflow. */
1038 struct op *new_stack;
1039 int old_size = (char *) limit - (char *) stack;
1040 int new_size = 2 * old_size;
1041 if (stack != init_stack)
1042 new_stack = (struct op *) xrealloc (stack, new_size);
1045 new_stack = (struct op *) xmalloc (new_size);
1046 memcpy (new_stack, stack, old_size);
1049 top = (struct op *) ((char *) new_stack + old_size);
1050 limit = (struct op *) ((char *) new_stack + new_size);
1054 top->prio = prio & ~EXTRACT_PRIO(RIGHT_ASSOC);
1059 result = (top[1].value != 0);
1061 CPP_ICE ("unbalanced stack in #if");
1062 else if (!(top[1].flags & HAVE_VALUE))
1064 SYNTAX_ERROR ("#if with no expression");
1066 result = 0; /* Return 0 on syntax error. */
1069 /* Free dynamic stack if we allocated one. */
1070 if (stack != init_stack)
1075 static const unsigned char *
1076 op_as_text (pfile, op)
1084 return cpp_token_as_text (pfile, &token);