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/*
* Copyright (c) 2002-2006 The TenDRA Project <http://www.tendra.org/>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of The TenDRA Project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific, prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
* IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $Id$
*/
/*
Crown Copyright (c) 1997
This TenDRA(r) Computer Program is subject to Copyright
owned by the United Kingdom Secretary of State for Defence
acting through the Defence Evaluation and Research Agency
(DERA). It is made available to Recipients with a
royalty-free licence for its use, reproduction, transfer
to other parties and amendment for any purpose not excluding
product development provided that any such use et cetera
shall be deemed to be acceptance of the following conditions:-
(1) Its Recipients shall ensure that this Notice is
reproduced upon any copies or amended versions of it;
(2) Any amended version of it shall be clearly marked to
show both the nature of and the organisation responsible
for the relevant amendment or amendments;
(3) Its onward transfer from a recipient to another
party shall be deemed to be that party's acceptance of
these conditions;
(4) DERA gives no warranty or assurance as to its
quality or suitability for any purpose and DERA accepts
no liability whatsoever in relation to any use to which
it may be put.
*/
#include "config.h"
#include "c_types.h"
#include "exp_ops.h"
#include "error.h"
#include "catalog.h"
#include "operator.h"
#include "quality.h"
#include "syntax.h"
/*
CHECKING CONTROL FLAG
This flag may be set to true to temporarily disable the checks in
this module.
*/
int suppress_quality = 0;
/*
TABLE OF OPERATIONS
This table gives the list of operations checked by check_paren. They
are listed in order of decreasing precedence. Calls to check_paren
give an entry point into this table beyond which checks are applied.
For example, left shift operations are checked from PAREN_PLUS which
detects 'a << b + c', 'a << b - c', 'a + b << c' and 'a - b << c'.
*/
static struct {
unsigned tag;
int op;
} paren_ops[] = {
{ exp_or_tag, lex_or_H1 }, /* PAREN_OR */
{ exp_xor_tag, lex_xor_H1 }, /* PAREN_XOR */
{ exp_and_tag, lex_and_H1 }, /* PAREN_AND */
{ exp_compare_tag, lex_eq }, /* PAREN_EQUALITY */
{ exp_test_tag, lex_eq }, /* PAREN_RELATION */
{ exp_plus_tag, lex_plus }, /* PAREN_PLUS */
{ exp_minus_tag, lex_minus } /* PAREN_MINUS */
};
/*
FIND AN EXPRESSION TAG
This routine finds the tag associated with the expression e for unusual
parenthesis analysis etc. Note that an integer constant expression may
have been evaluated to give a simple integer constant, however the top
level operation giving rise to this constant is held in the etag field.
*/
static unsigned
exp_tag (EXP e)
{
unsigned tag = TAG_exp(e);
if (tag == exp_int_lit_tag) {
/* Allow for evaluated constants */
tag = DEREF_unsigned(exp_int_lit_etag(e));
}
return (tag);
}
/*
CHECK FOR DUBIOUS SHIFTS AND BIT OPERATIONS
For various pairs of operations, op1 and op2, the resolution of the
expression 'a op1 b op2 c' to '( a op1 b ) op2 c' or 'a op1 ( b op2 c )'
is not obvious. This routine checks whether the expression 'a op b'
is of this form, checking the operations starting from position n in
the table paren_ops.
*/
void
check_paren(int n, int op, EXP a, EXP b)
{
if (!suppress_quality) {
int i;
/* Check first operand */
unsigned tag = exp_tag(a);
for (i = n; i < array_size(paren_ops); i++) {
if (tag == paren_ops[i].tag) {
int op1 = paren_ops[i].op;
if (op1 == lex_eq) {
op1 = op_token(a, op1);
}
report(crt_loc, ERR_expr_paren_left(op1, op));
break;
}
}
/* Check second operand */
tag = exp_tag(b);
for (i = n; i < array_size(paren_ops); i++) {
if (tag == paren_ops[i].tag) {
int op2 = paren_ops[i].op;
if (op2 == lex_eq) {
op2 = op_token(b, op2);
}
report(crt_loc, ERR_expr_paren_right(op, op2));
break;
}
}
}
return;
}
/*
CHECK FOR DUBIOUS RELATIONS
This routine checks for dubious relations such as 'a < b < c' which
do not have their mathematical meaning.
*/
void
check_relation(int op, EXP a, EXP b)
{
if (!suppress_quality) {
/* Check first operand */
unsigned tag = exp_tag(a);
if (tag == exp_compare_tag) {
int tst = op_token(a, op);
report(crt_loc, ERR_expr_rel_paren(tst, op));
} else if (tag == exp_test_tag) {
int tst = op_token(a, op);
report(crt_loc, ERR_expr_rel_paren(tst, op));
}
/* Check second operand */
tag = exp_tag(b);
if (tag == exp_compare_tag) {
int tst = op_token(b, op);
report(crt_loc, ERR_expr_rel_paren(op, tst));
} else if (tag == exp_test_tag) {
int tst = op_token(b, op);
report(crt_loc, ERR_expr_rel_paren(op, tst));
}
}
return;
}
/*
CHECK FOR DUBIOUS LOGICAL EXPRESSIONS
The resolution of 'a && b || c' to '( a && b ) || c' is odd. This
routine checks a logical or expression to see if it is of this form.
*/
void
check_logic(EXP a, EXP b)
{
if (!suppress_quality) {
if (exp_tag(a) == exp_log_and_tag) {
int op1 = lex_logical_Hand_H1;
int op2 = lex_logical_Hor_H1;
report(crt_loc, ERR_expr_paren_left(op1, op2));
}
if (exp_tag(b) == exp_log_and_tag) {
int op1 = lex_logical_Hor_H1;
int op2 = lex_logical_Hand_H1;
report(crt_loc, ERR_expr_paren_right(op1, op2));
}
}
return;
}