/*
 * Copyright (C) 2018 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 <stdlib.h>
#include "parse.h"
#include "smatch.h"
#include "smatch_slist.h"
#include "smatch_extra.h"

static int my_id;
static int barrier_id;

STATE(nospec);

static bool in_nospec_stmt;

static struct smatch_state *unmatched_state(struct sm_state *sm)
{
        struct range_list *rl;

        if (__in_function_def && !get_user_rl_var_sym(sm->name, sm->sym, &rl))
                return &nospec;
        return &undefined;
}

bool is_nospec(struct expression *expr)
{
        char *macro;

        if (in_nospec_stmt)
                return true;
        if (!expr)
                return false;
        if (get_state_expr(my_id, expr) == &nospec)
                return true;
        macro = get_macro_name(expr->pos);
        if (macro && strcmp(macro, "array_index_nospec") == 0)
                return true;
        return false;
}

static void nospec_assign(struct expression *expr)
{
        if (is_nospec(expr->right))
                set_state_expr(my_id, expr->left, &nospec);
}

static void set_param_nospec(const char *name, struct symbol *sym, char *key, char *value)
{
        char fullname[256];

        if (strcmp(key, "*$") == 0)
                snprintf(fullname, sizeof(fullname), "*%s", name);
        else if (strncmp(key, "$", 1) == 0)
                snprintf(fullname, 256, "%s%s", name, key + 1);
        else
                return;

        set_state(my_id, fullname, sym, &nospec);
}

static void match_call_info(struct expression *expr)
{
        struct expression *arg;
        int i = 0;

        FOR_EACH_PTR(expr->args, arg) {
                if (get_state_expr(my_id, arg) == &nospec)
                        sql_insert_caller_info(expr, NOSPEC, i, "$", "");
                i++;
        } END_FOR_EACH_PTR(arg);
}

static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
{
        struct range_list *rl;

        if (!get_user_rl_var_sym(sm->name, sm->sym, &rl))
                return;
        sql_insert_caller_info(call, NOSPEC, param, printed_name, "");
}

static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
{
        struct stree *start_states = get_start_states();
        struct symbol *returned_sym;
        struct sm_state *sm;
        const char *param_name;
        struct range_list *rl;
        int param;

        returned_sym = expr_to_sym(expr);

        FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
                if (get_state_stree(start_states, my_id, sm->name, sm->sym) == sm->state)
                        continue;
                param = get_param_num_from_sym(sm->sym);
                if (param < 0) {
                        if (!returned_sym || returned_sym != sm->sym)
                                continue;
                        param = -1;
                }

                param_name = get_param_name(sm);
                if (!param_name)
                        continue;
                if (param != -1 && strcmp(param_name, "$") == 0)
                        continue;

                if (!get_user_rl_var_sym(sm->name, sm->sym, &rl))
                        continue;

                sql_insert_return_states(return_id, return_ranges, NOSPEC, param, param_name, "");
        } END_FOR_EACH_SM(sm);

        if (is_nospec(expr) && get_user_rl(expr, &rl))
                sql_insert_return_states(return_id, return_ranges, NOSPEC, -1, "$", "");

        if (get_state(barrier_id, "barrier", NULL) == &nospec)
                sql_insert_return_states(return_id, return_ranges, NOSPEC_WB, -1, "", "");
}

static int is_return_statement(void)
{
        if (__cur_stmt && __cur_stmt->type == STMT_RETURN)
                return 1;
        return 0;
}

static void db_returns_nospec(struct expression *expr, int param, char *key, char *value)
{
        struct expression *call;
        struct expression *arg;
        char *name;
        struct symbol *sym;

        call = expr;
        while (call->type == EXPR_ASSIGNMENT)
                call = strip_expr(call->right);
        if (call->type != EXPR_CALL)
                return;

        if (param == -1 && expr->type == EXPR_ASSIGNMENT) {
                name = get_variable_from_key(expr->left, key, &sym);
        } else if (param == -1 && is_return_statement()) {
                in_nospec_stmt = true;
                return;
        } else {
                arg = get_argument_from_call_expr(call->args, param);
                if (!arg)
                        return;
                name = get_variable_from_key(arg, key, &sym);
        }
        if (!name || !sym)
                goto free;

        set_state(my_id, name, sym, &nospec);
free:
        free_string(name);
}

static int is_nospec_asm(struct statement *stmt)
{
        char *macro;

        if (!stmt || stmt->type != STMT_ASM)
                return 0;
        if (!stmt->asm_string)
                return 0;
        macro = get_macro_name(stmt->asm_string->pos);
        if (!macro || strcmp(macro, "CALL_NOSPEC") != 0)
                return 0;
        return 1;
}

static void match_asm(struct statement *stmt)
{
        if (is_nospec_asm(stmt))
                in_nospec_stmt = true;
}

static void match_after_nospec_asm(struct statement *stmt)
{
        in_nospec_stmt = false;
}

static void mark_user_data_as_nospec(void)
{
        struct stree *stree;
        struct symbol *type;
        struct sm_state *sm;

        stree = get_user_stree();
        FOR_EACH_SM(stree, sm) {
                if (is_whole_rl(estate_rl(sm->state)))
                        continue;
                type = estate_type(sm->state);
                if (!type || type->type != SYM_BASETYPE)
                        continue;
                if (!is_capped_var_sym(sm->name, sm->sym))
                        continue;
                set_state(my_id, sm->name, sm->sym, &nospec);
        } END_FOR_EACH_SM(sm);
        free_stree(&stree);
}

static void match_barrier(struct statement *stmt)
{
        char *macro;

        macro = get_macro_name(stmt->pos);
        if (!macro)
                return;
        if (strcmp(macro, "rmb") != 0 &&
            strcmp(macro, "smp_rmb") != 0 &&
            strcmp(macro, "barrier_nospec") != 0 &&
            strcmp(macro, "preempt_disable") != 0)
                return;

        set_state(barrier_id, "barrier", NULL, &nospec);
        mark_user_data_as_nospec();
}

static void db_returns_barrier(struct expression *expr, int param, char *key, char *value)
{
        mark_user_data_as_nospec();
}

static void select_return_stmt_cnt(struct expression *expr, int param, char *key, char *value)
{
        int cnt;

        cnt = atoi(value);
        if (cnt > 400)
                mark_user_data_as_nospec();
}

void check_nospec(int id)
{
        my_id = id;

        add_hook(&nospec_assign, ASSIGNMENT_HOOK);

        select_caller_info_hook(set_param_nospec, NOSPEC);
        add_unmatched_state_hook(my_id, &unmatched_state);

        add_hook(&match_call_info, FUNCTION_CALL_HOOK);
        add_member_info_callback(my_id, struct_member_callback);
        add_split_return_callback(&returned_struct_members);
        select_return_states_hook(NOSPEC, &db_returns_nospec);
        select_return_states_hook(NOSPEC_WB, &db_returns_barrier);
        select_return_states_hook(STMT_CNT, &select_return_stmt_cnt);

        add_hook(&match_asm, ASM_HOOK);
        add_hook(&match_after_nospec_asm, STMT_HOOK_AFTER);
}

void check_nospec_barrier(int id)
{
        barrier_id = id;

        add_hook(&match_barrier, ASM_HOOK);
}