/*
 * Copyright (C) 2012 Oracle.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
 */

#include "scope.h"
#include "smatch.h"
#include "smatch_slist.h"
#include "smatch_expression_stacks.h"

static int my_id;

static struct string_list *ignored_macros;
static struct position old_pos;

static struct smatch_state *alloc_my_state(struct expression *expr)
{
        struct smatch_state *state;
        char *name;

        expr = strip_expr(expr);
        name = expr_to_str(expr);
        if (!name)
                return NULL;

        state = __alloc_smatch_state(0);
        state->name = alloc_sname(name);
        free_string(name);
        state->data = expr;
        return state;
}

static int defined_inside_macro(struct position macro_pos, struct expression *expr)
{
        char *name;
        struct symbol *sym;
        int ret = 0;

        name = expr_to_var_sym(expr, &sym);
        if (!name || !sym)
                goto free;
        if (!sym->scope || !sym->scope->token)
                goto free;
        if (positions_eq(macro_pos, sym->scope->token->pos))
                ret = 1;
free:
        free_string(name);
        return ret;
}

static int affected_inside_macro_before(struct expression *expr)
{
        struct sm_state *sm;
        struct sm_state *tmp;
        struct expression *old_mod;

        sm = get_sm_state_expr(my_id, expr);
        if (!sm)
                return 0;

        FOR_EACH_PTR(sm->possible, tmp) {
                old_mod = tmp->state->data;
                if (!old_mod)
                        continue;
                if (positions_eq(old_mod->pos, expr->pos))
                        return 1;
        } END_FOR_EACH_PTR(tmp);
        return 0;
}

static int is_ignored_macro(const char *macro)
{
        char *tmp;

        FOR_EACH_PTR(ignored_macros, tmp) {
                if (!strcmp(tmp, macro))
                        return 1;
        } END_FOR_EACH_PTR(tmp);
        return 0;
}

static void match_unop(struct expression *raw_expr)
{
        struct expression *expr;
        char *macro, *name;

        if (raw_expr->op != SPECIAL_INCREMENT && raw_expr->op != SPECIAL_DECREMENT)
                return;

        macro = get_macro_name(raw_expr->pos);
        if (!macro)
                return;

        expr = strip_expr(raw_expr->unop);

        if (defined_inside_macro(expr->pos, expr))
                return;

        if (is_ignored_macro(macro))
                return;

        if (!affected_inside_macro_before(expr)) {
                set_state_expr(my_id, expr, alloc_my_state(expr));
                old_pos = expr->pos;
                return;
        }

        if (!positions_eq(old_pos, expr->pos))
                return;

        name = expr_to_str(raw_expr);
        sm_warning("side effect in macro '%s' doing '%s'",
                macro, name);
        free_string(name);
}

static void match_stmt(struct statement *stmt)
{
        if (!positions_eq(old_pos, stmt->pos))
                old_pos.line = 0;
}

static void register_ignored_macros(void)
{
        struct token *token;
        char *macro;
        char name[256];

        snprintf(name, 256, "%s.ignore_side_effects", option_project_str);

        token = get_tokens_file(name);
        if (!token)
                return;
        if (token_type(token) != TOKEN_STREAMBEGIN)
                return;
        token = token->next;
        while (token_type(token) != TOKEN_STREAMEND) {
                if (token_type(token) != TOKEN_IDENT)
                        return;
                macro = alloc_string(show_ident(token->ident));
                add_ptr_list(&ignored_macros, macro);
                token = token->next;
        }
        clear_token_alloc();
}

void check_macro_side_effects(int id)
{
        my_id = id;

        if (!option_spammy)
                return;

        set_dynamic_states(my_id);
        add_hook(&match_unop, OP_HOOK);
        add_hook(&match_stmt, STMT_HOOK);
        register_ignored_macros();
}