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/*
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 * Copyright (c) 2002-2006 The TenDRA Project <http://www.tendra.org/>.
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions are met:
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 *
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 * 1. Redistributions of source code must retain the above copyright notice,
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 *    this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright notice,
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 *    this list of conditions and the following disclaimer in the documentation
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 *    and/or other materials provided with the distribution.
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 * 3. Neither the name of The TenDRA Project nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific, prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
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 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
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 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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 * EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 *
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 * $Id$
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 */
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/*
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    		 Crown Copyright (c) 1997
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    This TenDRA(r) Computer Program is subject to Copyright
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    owned by the United Kingdom Secretary of State for Defence
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    acting through the Defence Evaluation and Research Agency
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    (DERA).  It is made available to Recipients with a
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    royalty-free licence for its use, reproduction, transfer
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    to other parties and amendment for any purpose not excluding
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    product development provided that any such use et cetera
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    shall be deemed to be acceptance of the following conditions:-
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        (1) Its Recipients shall ensure that this Notice is
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        reproduced upon any copies or amended versions of it;
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        (2) Any amended version of it shall be clearly marked to
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        show both the nature of and the organisation responsible
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        for the relevant amendment or amendments;
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        (3) Its onward transfer from a recipient to another
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        party shall be deemed to be that party's acceptance of
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        these conditions;
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        (4) DERA gives no warranty or assurance as to its
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        quality or suitability for any purpose and DERA accepts
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        no liability whatsoever in relation to any use to which
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        it may be put.
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*/
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#include "config.h"
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#include "c_types.h"
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#include "exp_ops.h"
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#include "error.h"
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#include "catalog.h"
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#include "operator.h"
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#include "quality.h"
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#include "syntax.h"
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/*
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    CHECKING CONTROL FLAG
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    This flag may be set to true to temporarily disable the checks in
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    this module.
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*/
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int suppress_quality = 0;
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/*
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    TABLE OF OPERATIONS
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    This table gives the list of operations checked by check_paren.  They
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    are listed in order of decreasing precedence.  Calls to check_paren
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    give an entry point into this table beyond which checks are applied.
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    For example, left shift operations are checked from PAREN_PLUS which
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    detects 'a << b + c', 'a << b - c', 'a + b << c' and 'a - b << c'.
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*/
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static struct {
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	unsigned tag;
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	int op;
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} paren_ops[] = {
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	{ exp_or_tag, lex_or_H1 },	/* PAREN_OR */
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	{ exp_xor_tag, lex_xor_H1 },	/* PAREN_XOR */
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	{ exp_and_tag, lex_and_H1 },	/* PAREN_AND */
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	{ exp_compare_tag, lex_eq },	/* PAREN_EQUALITY */
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	{ exp_test_tag, lex_eq },	/* PAREN_RELATION */
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	{ exp_plus_tag, lex_plus },	/* PAREN_PLUS */
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	{ exp_minus_tag, lex_minus }	/* PAREN_MINUS */
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};
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/*
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    FIND AN EXPRESSION TAG
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    This routine finds the tag associated with the expression e for unusual
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    parenthesis analysis etc.  Note that an integer constant expression may
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    have been evaluated to give a simple integer constant, however the top
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    level operation giving rise to this constant is held in the etag field.
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*/
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static unsigned
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exp_tag (EXP e)
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{
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	unsigned tag = TAG_exp(e);
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	if (tag == exp_int_lit_tag) {
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		/* Allow for evaluated constants */
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		tag = DEREF_unsigned(exp_int_lit_etag(e));
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	}
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	return (tag);
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}
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/*
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    CHECK FOR DUBIOUS SHIFTS AND BIT OPERATIONS
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    For various pairs of operations, op1 and op2, the resolution of the
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    expression 'a op1 b op2 c' to '( a op1 b ) op2 c' or 'a op1 ( b op2 c )'
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    is not obvious.  This routine checks whether the expression 'a op b'
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    is of this form, checking the operations starting from position n in
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    the table paren_ops.
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*/
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void
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check_paren(int n, int op, EXP a, EXP b)
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{
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	if (!suppress_quality) {
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		int i;
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		/* Check first operand */
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		unsigned tag = exp_tag(a);
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		for (i = n; i < array_size(paren_ops); i++) {
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			if (tag == paren_ops[i].tag) {
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				int op1 = paren_ops[i].op;
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				if (op1 == lex_eq) {
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					op1 = op_token(a, op1);
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				}
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				report(crt_loc, ERR_expr_paren_left(op1, op));
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				break;
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			}
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		}
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		/* Check second operand */
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		tag = exp_tag(b);
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		for (i = n; i < array_size(paren_ops); i++) {
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			if (tag == paren_ops[i].tag) {
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				int op2 = paren_ops[i].op;
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				if (op2 == lex_eq) {
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					op2 = op_token(b, op2);
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				}
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				report(crt_loc, ERR_expr_paren_right(op, op2));
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				break;
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			}
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		}
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	}
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	return;
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}
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/*
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    CHECK FOR DUBIOUS RELATIONS
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175 
    This routine checks for dubious relations such as 'a < b < c' which
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    do not have their mathematical meaning.
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*/
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void
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check_relation(int op, EXP a, EXP b)
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{
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	if (!suppress_quality) {
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		/* Check first operand */
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		unsigned tag = exp_tag(a);
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		if (tag == exp_compare_tag) {
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			int tst = op_token(a, op);
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			report(crt_loc, ERR_expr_rel_paren(tst, op));
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		} else if (tag == exp_test_tag) {
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			int tst = op_token(a, op);
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			report(crt_loc, ERR_expr_rel_paren(tst, op));
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		}
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		/* Check second operand */
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		tag = exp_tag(b);
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		if (tag == exp_compare_tag) {
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			int tst = op_token(b, op);
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			report(crt_loc, ERR_expr_rel_paren(op, tst));
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		} else if (tag == exp_test_tag) {
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			int tst = op_token(b, op);
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			report(crt_loc, ERR_expr_rel_paren(op, tst));
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		}
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	}
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	return;
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}
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206 
 
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/*
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    CHECK FOR DUBIOUS LOGICAL EXPRESSIONS
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210 
    The resolution of 'a && b || c' to '( a && b ) || c' is odd.  This
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    routine checks a logical or expression to see if it is of this form.
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*/
213 
 
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void
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check_logic(EXP a, EXP b)
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{
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	if (!suppress_quality) {
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		if (exp_tag(a) == exp_log_and_tag) {
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			int op1 = lex_logical_Hand_H1;
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			int op2 = lex_logical_Hor_H1;
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			report(crt_loc, ERR_expr_paren_left(op1, op2));
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		}
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		if (exp_tag(b) == exp_log_and_tag) {
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			int op1 = lex_logical_Hor_H1;
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			int op2 = lex_logical_Hand_H1;
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			report(crt_loc, ERR_expr_paren_right(op1, op2));
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		}
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	}
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	return;
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}