/*
 * Copyright (C) 2008 Dan Carpenter.
 *
 * 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
 */

/*
 * smatch_extra.c is supposed to track the value of every variable.
 *
 */

#define _GNU_SOURCE
#include <string.h>

#include <stdlib.h>
#include <errno.h>
#ifndef __USE_ISOC99
#define __USE_ISOC99
#endif
#include <limits.h>
#include "parse.h"
#include "smatch.h"
#include "smatch_slist.h"
#include "smatch_extra.h"

static int my_id;
static int link_id;

static void match_link_modify(struct sm_state *sm, struct expression *mod_expr);

struct string_list *__ignored_macros = NULL;
int in_warn_on_macro(void)
{
        struct statement *stmt;
        char *tmp;
        char *macro;

        stmt = get_current_statement();
        if (!stmt)
                return 0;
        macro = get_macro_name(stmt->pos);
        if (!macro)
                return 0;

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

typedef void (mod_hook)(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state);
DECLARE_PTR_LIST(void_fn_list, mod_hook *);
static struct void_fn_list *extra_mod_hooks;
static struct void_fn_list *extra_nomod_hooks;

void add_extra_mod_hook(mod_hook *fn)
{
        mod_hook **p = malloc(sizeof(mod_hook *));
        *p = fn;
        add_ptr_list(&extra_mod_hooks, p);
}

void add_extra_nomod_hook(mod_hook *fn)
{
        mod_hook **p = malloc(sizeof(mod_hook *));
        *p = fn;
        add_ptr_list(&extra_nomod_hooks, p);
}

void call_extra_hooks(struct void_fn_list *hooks, const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
{
        mod_hook **fn;

        FOR_EACH_PTR(hooks, fn) {
                (*fn)(name, sym, expr, state);
        } END_FOR_EACH_PTR(fn);
}

void call_extra_mod_hooks(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
{
        call_extra_hooks(extra_mod_hooks, name, sym, expr, state);
}

void call_extra_nomod_hooks(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
{
        call_extra_hooks(extra_nomod_hooks, name, sym, expr, state);
}

static void set_union_info(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
{
        struct symbol *type, *tmp, *inner_type, *inner, *new_type;
        struct expression *deref, *member_expr;
        struct smatch_state *new;
        int offset, inner_offset;
        static bool in_recurse;
        char *member_name;

        if (__in_fake_assign)
                return;

        if (in_recurse)
                return;
        in_recurse = true;

        if (!expr || expr->type != EXPR_DEREF || !expr->member)
                goto done;
        offset = get_member_offset_from_deref(expr);
        if (offset < 0)
                goto done;

        deref = strip_expr(expr->deref);
        type = get_type(deref);
        if (type_is_ptr(type))
                type = get_real_base_type(type);
        if (!type || type->type != SYM_STRUCT)
                goto done;

        FOR_EACH_PTR(type->symbol_list, tmp) {
                inner_type = get_real_base_type(tmp);
                if (!inner_type || inner_type->type != SYM_UNION)
                        continue;

                inner = first_ptr_list((struct ptr_list *)inner_type->symbol_list);
                if (!inner || !inner->ident)
                        continue;

                inner_offset = get_member_offset(type, inner->ident->name);
                if (inner_offset < offset)
                        continue;
                if (inner_offset > offset)
                        goto done;

                FOR_EACH_PTR(inner_type->symbol_list, inner) {
                        struct symbol *tmp_type;

                        if (!inner->ident || inner->ident == expr->member)
                                continue;
                        tmp_type = get_real_base_type(inner);
                        if (tmp_type && tmp_type->type == SYM_STRUCT)
                                continue;
                        member_expr = deref;
                        if (tmp->ident)
                                member_expr = member_expression(member_expr, '.', tmp->ident);
                        member_expr = member_expression(member_expr, expr->op, inner->ident);
                        member_name = expr_to_var(member_expr);
                        if (!member_name)
                                continue;
                        new_type = get_real_base_type(inner);
                        new = alloc_estate_rl(cast_rl(new_type, estate_rl(state)));
                        set_extra_mod_helper(member_name, sym, member_expr, new);
                        free_string(member_name);
                } END_FOR_EACH_PTR(inner);
        } END_FOR_EACH_PTR(tmp);

done:
        in_recurse = false;
}

static bool in_param_set;
void set_extra_mod_helper(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
{
        struct expression *faked;

        if (!expr)
                expr = gen_expression_from_name_sym(name, sym);
        remove_from_equiv(name, sym);
        set_union_info(name, sym, expr, state);
        call_extra_mod_hooks(name, sym, expr, state);
        faked = get_faked_expression();
        if (!faked ||
            (faked->type == EXPR_ASSIGNMENT && is_fresh_alloc(faked->right)))
                update_mtag_data(expr, state);
        if (in_param_set &&
            estate_is_unknown(state) && !get_state(SMATCH_EXTRA, name, sym))
                return;
        set_state(SMATCH_EXTRA, name, sym, state);
}

static void set_extra_nomod_helper(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
{
        call_extra_nomod_hooks(name, sym, expr, state);
        set_state(SMATCH_EXTRA, name, sym, state);
}

static char *get_pointed_at(const char *name, struct symbol *sym, struct symbol **new_sym)
{
        struct expression *assigned;

        /*
         * Imagine we have an assignment: "foo = &addr;" then the other name
         * of "*foo" is addr.
         */

        if (name[0] != '*')
                return NULL;
        if (strcmp(name + 1, sym->ident->name) != 0)
                return NULL;

        assigned = get_assigned_expr_name_sym(sym->ident->name, sym);
        if (!assigned)
                return NULL;
        assigned = strip_parens(assigned);
        if (assigned->type != EXPR_PREOP || assigned->op != '&')
                return NULL;

        return expr_to_var_sym(assigned->unop, new_sym);
}

char *get_other_name_sym_from_chunk(const char *name, const char *chunk, int len, struct symbol *sym, struct symbol **new_sym)
{
        struct expression *assigned;
        char *orig_name = NULL;
        char buf[256];
        char *ret;

        assigned = get_assigned_expr_name_sym(chunk, sym);
        if (!assigned)
                return NULL;
        if (assigned->type == EXPR_CALL)
                return map_call_to_other_name_sym(name, sym, new_sym);
        if (assigned->type == EXPR_PREOP && assigned->op == '&') {

                orig_name = expr_to_var_sym(assigned, new_sym);
                if (!orig_name || !*new_sym)
                        goto free;

                snprintf(buf, sizeof(buf), "%s.%s", orig_name + 1, name + len);
                ret = alloc_string(buf);
                free_string(orig_name);
                return ret;
        }

        orig_name = expr_to_var_sym(assigned, new_sym);
        if (!orig_name || !*new_sym)
                goto free;

        snprintf(buf, sizeof(buf), "%s->%s", orig_name, name + len);
        ret = alloc_string(buf);
        free_string(orig_name);
        return ret;
free:
        free_string(orig_name);
        return NULL;
}

static char *get_long_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym, bool use_stack)
{
        struct expression *tmp;
        struct sm_state *sm;
        char buf[256];

        /*
         * Just prepend the name with a different name/sym and return that.
         * For example, if we set "foo->bar = bar;" then the other name
         * for "bar->baz" is "foo->bar->baz".  Or if we have "foo = bar;" then
         * the other name for "bar" is "foo".  A third option is if we have
         * "foo = bar;" then another name for "*bar" is "*foo".
         */

        FOR_EACH_MY_SM(check_assigned_expr_id, __get_cur_stree(), sm) {
                tmp = sm->state->data;
                if (!tmp || tmp->type != EXPR_SYMBOL)
                        continue;
                if (tmp->symbol == sym)
                        goto found;
        } END_FOR_EACH_SM(sm);

        return NULL;

found:
        if (!use_stack && name[tmp->symbol->ident->len] != '-')
                return NULL;

        if (name[0] == '*' && strcmp(name + 1, tmp->symbol_name->name) == 0)
                snprintf(buf, sizeof(buf), "*%s", sm->name);
        else if (name[tmp->symbol->ident->len] == '-' ||
                 name[tmp->symbol->ident->len] == '.')
                snprintf(buf, sizeof(buf), "%s%s", sm->name, name + tmp->symbol->ident->len);
        else if (strcmp(name, tmp->symbol_name->name) == 0)
                snprintf(buf, sizeof(buf), "%s", sm->name);
        else
                return NULL;

        *new_sym = sm->sym;
        return alloc_string(buf);
}

char *get_other_name_sym_helper(const char *name, struct symbol *sym, struct symbol **new_sym, bool use_stack)
{
        char buf[256];
        char *ret;
        int len;

        *new_sym = NULL;

        if (!sym || !sym->ident)
                return NULL;

        ret = get_pointed_at(name, sym, new_sym);
        if (ret)
                return ret;

        ret = map_long_to_short_name_sym(name, sym, new_sym, use_stack);
        if (ret)
                return ret;

        len = snprintf(buf, sizeof(buf), "%s", name);
        if (len >= sizeof(buf) - 2)
                return NULL;

        while (use_stack && len >= 1) {
                if (buf[len] == '>' && buf[len - 1] == '-') {
                        len--;
                        buf[len] = '\0';
                        ret = get_other_name_sym_from_chunk(name, buf, len + 2, sym, new_sym);
                        if (ret)
                                return ret;
                }
                len--;
        }

        ret = get_long_name_sym(name, sym, new_sym, use_stack);
        if (ret)
                return ret;

        return NULL;
}

char *get_other_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym)
{
        return get_other_name_sym_helper(name, sym, new_sym, true);
}

char *get_other_name_sym_nostack(const char *name, struct symbol *sym, struct symbol **new_sym)
{
        return get_other_name_sym_helper(name, sym, new_sym, false);
}

void set_extra_mod(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
{
        char *new_name;
        struct symbol *new_sym;

        set_extra_mod_helper(name, sym, expr, state);
        new_name = get_other_name_sym_nostack(name, sym, &new_sym);
        if (new_name && new_sym)
                set_extra_mod_helper(new_name, new_sym, NULL, state);
        free_string(new_name);
}

static struct expression *chunk_get_array_base(struct expression *expr)
{
        /*
         * The problem with is_array() is that it only returns true for things
         * like foo[1] but not for foo[1].bar.
         *
         */
        expr = strip_expr(expr);
        while (expr && expr->type == EXPR_DEREF)
                expr = strip_expr(expr->deref);
        return get_array_base(expr);
}

static int chunk_has_array(struct expression *expr)
{
        return !!chunk_get_array_base(expr);
}

static void clear_array_states(struct expression *array)
{
        struct sm_state *sm;

        sm = get_sm_state_expr(link_id, array);
        if (sm)
                match_link_modify(sm, NULL);
}

static void set_extra_array_mod(struct expression *expr, struct smatch_state *state)
{
        struct expression *array;
        struct var_sym_list *vsl;
        struct var_sym *vs;
        char *name;
        struct symbol *sym;

        array = chunk_get_array_base(expr);

        name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
        if (!name || !vsl) {
                clear_array_states(array);
                goto free;
        }

        FOR_EACH_PTR(vsl, vs) {
                store_link(link_id, vs->var, vs->sym, name, sym);
        } END_FOR_EACH_PTR(vs);

        call_extra_mod_hooks(name, sym, expr, state);
        set_state(SMATCH_EXTRA, name, sym, state);
free:
        free_string(name);
}

void set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
{
        struct symbol *sym;
        char *name;

        if (chunk_has_array(expr)) {
                set_extra_array_mod(expr, state);
                return;
        }

        expr = strip_expr(expr);
        name = expr_to_var_sym(expr, &sym);
        if (!name || !sym)
                goto free;
        set_extra_mod(name, sym, expr, state);
free:
        free_string(name);
}

void set_extra_nomod(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
{
        char *new_name;
        struct symbol *new_sym;
        struct relation *rel;
        struct smatch_state *orig_state;

        orig_state = get_state(SMATCH_EXTRA, name, sym);

        /* don't save unknown states if leaving it blank is the same */
        if (!orig_state && estate_is_unknown(state))
                return;

        new_name = get_other_name_sym(name, sym, &new_sym);
        if (new_name && new_sym)
                set_extra_nomod_helper(new_name, new_sym, expr, state);
        free_string(new_name);

        if (!estate_related(orig_state)) {
                set_extra_nomod_helper(name, sym, expr, state);
                return;
        }

        set_related(state, estate_related(orig_state));
        FOR_EACH_PTR(estate_related(orig_state), rel) {
                struct smatch_state *estate;

                estate = get_state(SMATCH_EXTRA, rel->name, rel->sym);
                if (!estate)
                        continue;
                set_extra_nomod_helper(rel->name, rel->sym, expr, clone_estate_cast(estate_type(estate), state));
        } END_FOR_EACH_PTR(rel);
}

void set_extra_nomod_vsl(const char *name, struct symbol *sym, struct var_sym_list *vsl, struct expression *expr, struct smatch_state *state)
{
        struct var_sym *vs;

        FOR_EACH_PTR(vsl, vs) {
                store_link(link_id, vs->var, vs->sym, name, sym);
        } END_FOR_EACH_PTR(vs);

        set_extra_nomod(name, sym, expr, state);
}

/*
 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
 */
void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
{
        struct var_sym_list *vsl;
        struct var_sym *vs;
        char *name;
        struct symbol *sym;

        name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
        if (!name || !vsl)
                goto free;
        FOR_EACH_PTR(vsl, vs) {
                store_link(link_id, vs->var, vs->sym, name, sym);
        } END_FOR_EACH_PTR(vs);

        set_extra_nomod(name, sym, expr, state);
free:
        free_string(name);
}

static void set_extra_true_false(const char *name, struct symbol *sym,
                        struct smatch_state *true_state,
                        struct smatch_state *false_state)
{
        char *new_name;
        struct symbol *new_sym;
        struct relation *rel;
        struct smatch_state *orig_state;

        if (!true_state && !false_state)
                return;

        if (in_warn_on_macro())
                return;

        new_name = get_other_name_sym(name, sym, &new_sym);
        if (new_name && new_sym)
                set_true_false_states(SMATCH_EXTRA, new_name, new_sym, true_state, false_state);
        free_string(new_name);

        orig_state = get_state(SMATCH_EXTRA, name, sym);

        if (!estate_related(orig_state)) {
                set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
                return;
        }

        if (true_state)
                set_related(true_state, estate_related(orig_state));
        if (false_state)
                set_related(false_state, estate_related(orig_state));

        FOR_EACH_PTR(estate_related(orig_state), rel) {
                set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
                                true_state, false_state);
        } END_FOR_EACH_PTR(rel);
}

static void set_extra_chunk_true_false(struct expression *expr,
                                       struct smatch_state *true_state,
                                       struct smatch_state *false_state)
{
        struct var_sym_list *vsl;
        struct var_sym *vs;
        struct symbol *type;
        char *name;
        struct symbol *sym;

        if (in_warn_on_macro())
                return;

        type = get_type(expr);
        if (!type)
                return;

        name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
        if (!name || !vsl)
                goto free;
        FOR_EACH_PTR(vsl, vs) {
                store_link(link_id, vs->var, vs->sym, name, sym);
        } END_FOR_EACH_PTR(vs);

        set_true_false_states(SMATCH_EXTRA, name, sym,
                              clone_estate(true_state),
                              clone_estate(false_state));
free:
        free_string(name);
}

static void set_extra_expr_true_false(struct expression *expr,
                struct smatch_state *true_state,
                struct smatch_state *false_state)
{
        char *name;
        struct symbol *sym;
        sval_t sval;

        if (!true_state && !false_state)
                return;

        if (get_value(expr, &sval))
                return;

        expr = strip_expr(expr);
        name = expr_to_var_sym(expr, &sym);
        if (!name || !sym) {
                free_string(name);
                set_extra_chunk_true_false(expr, true_state, false_state);
                return;
        }
        set_extra_true_false(name, sym, true_state, false_state);
        free_string(name);
}

static int get_countdown_info(struct expression *condition, struct expression **unop, int *op, sval_t *right)
{
        struct expression *unop_expr;
        int comparison;
        sval_t limit;

        right->type = &int_ctype;
        right->value = 0;

        condition = strip_expr(condition);

        if (condition->type == EXPR_COMPARE) {
                comparison = remove_unsigned_from_comparison(condition->op);

                if (comparison != SPECIAL_GTE && comparison != '>')
                        return 0;
                if (!get_value(condition->right, &limit))
                        return 0;

                unop_expr = condition->left;
                if (unop_expr->type != EXPR_PREOP && unop_expr->type != EXPR_POSTOP)
                        return 0;
                if (unop_expr->op != SPECIAL_DECREMENT)
                        return 0;

                *unop = unop_expr;
                *op = comparison;
                *right = limit;

                return 1;
        }

        if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
                return 0;
        if (condition->op != SPECIAL_DECREMENT)
                return 0;

        *unop = condition;
        *op = '>';

        return 1;
}

static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
{
        struct expression *iter_var;
        struct expression *condition, *unop;
        struct symbol *type;
        struct sm_state *sm;
        struct smatch_state *estate;
        int op;
        sval_t start, right;

        right.type = &int_ctype;
        right.value = 0;

        condition = strip_expr(loop->iterator_pre_condition);
        if (!condition)
                return NULL;

        if (!get_countdown_info(condition, &unop, &op, &right))
                return NULL;

        iter_var = unop->unop;

        sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
        if (!sm)
                return NULL;
        if (sval_cmp(estate_min(sm->state), right) < 0)
                return NULL;
        start = estate_max(sm->state);

        type = get_type(iter_var);
        right = sval_cast(type, right);
        start = sval_cast(type, start);

        if  (sval_cmp(start, right) <= 0)
                return NULL;
        if (!sval_is_max(start))
                start.value--;

        if (op == SPECIAL_GTE)
                right.value--;

        if (unop->type == EXPR_PREOP) {
                right.value++;
                estate = alloc_estate_range(right, start);
                if (estate_has_hard_max(sm->state))
                        estate_set_hard_max(estate);
                estate_copy_fuzzy_max(estate, sm->state);
                set_extra_expr_mod(iter_var, estate);
        }
        if (unop->type == EXPR_POSTOP) {
                estate = alloc_estate_range(right, start);
                if (estate_has_hard_max(sm->state))
                        estate_set_hard_max(estate);
                estate_copy_fuzzy_max(estate, sm->state);
                set_extra_expr_mod(iter_var, estate);
        }
        return get_sm_state_expr(SMATCH_EXTRA, iter_var);
}

static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
                                                struct expression *condition)
{
        struct expression *iter_var;
        struct sm_state *sm;
        struct smatch_state *estate;
        sval_t start, end, max;
        struct symbol *type;

        iter_var = iter_expr->unop;
        sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
        if (!sm)
                return NULL;
        if (!estate_get_single_value(sm->state, &start))
                return NULL;
        if (!get_implied_value(condition->right, &end))
                return NULL;

        if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
                return NULL;

        switch (condition->op) {
        case SPECIAL_UNSIGNED_LT:
        case SPECIAL_NOTEQUAL:
        case '<':
                if (!sval_is_min(end))
                        end.value--;
                break;
        case SPECIAL_UNSIGNED_LTE:
        case SPECIAL_LTE:
                break;
        default:
                return NULL;
        }
        if (sval_cmp(end, start) < 0)
                return NULL;
        type = get_type(iter_var);
        start = sval_cast(type, start);
        end = sval_cast(type, end);
        estate = alloc_estate_range(start, end);
        if (get_hard_max(condition->right, &max)) {
                if (!get_macro_name(condition->pos))
                        estate_set_hard_max(estate);
                if (condition->op == '<' ||
                    condition->op == SPECIAL_UNSIGNED_LT ||
                    condition->op == SPECIAL_NOTEQUAL)
                        max.value--;
                max = sval_cast(type, max);
                estate_set_fuzzy_max(estate, max);
        }
        set_extra_expr_mod(iter_var, estate);
        return get_sm_state_expr(SMATCH_EXTRA, iter_var);
}

static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
                                                struct expression *condition)
{
        struct expression *iter_var;
        struct sm_state *sm;
        struct smatch_state *estate;
        sval_t start, end;

        iter_var = iter_expr->unop;
        sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
        if (!sm)
                return NULL;
        if (!estate_get_single_value(sm->state, &start))
                return NULL;
        if (!get_implied_min(condition->right, &end))
                end = sval_type_min(get_type(iter_var));
        end = sval_cast(estate_type(sm->state), end);
        if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
                return NULL;

        switch (condition->op) {
        case SPECIAL_NOTEQUAL:
        case '>':
                if (!sval_is_max(end))
                        end.value++;
                break;
        case SPECIAL_GTE:
                break;
        default:
                return NULL;
        }
        if (sval_cmp(end, start) > 0)
                return NULL;
        estate = alloc_estate_range(end, start);
        estate_set_hard_max(estate);
        estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
        set_extra_expr_mod(iter_var, estate);
        return get_sm_state_expr(SMATCH_EXTRA, iter_var);
}

static struct sm_state *handle_canonical_for_loops(struct statement *loop)
{
        struct expression *iter_expr;
        struct expression *condition;

        if (!loop->iterator_post_statement)
                return NULL;
        if (loop->iterator_post_statement->type != STMT_EXPRESSION)
                return NULL;
        iter_expr = loop->iterator_post_statement->expression;
        if (!loop->iterator_pre_condition)
                return NULL;
        if (loop->iterator_pre_condition->type != EXPR_COMPARE)
                return NULL;
        condition = loop->iterator_pre_condition;

        if (iter_expr->op == SPECIAL_INCREMENT)
                return handle_canonical_for_inc(iter_expr, condition);
        if (iter_expr->op == SPECIAL_DECREMENT)
                return handle_canonical_for_dec(iter_expr, condition);
        return NULL;
}

struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
{
        struct sm_state *ret;

        /*
         * Canonical loops are a hack.  The proper way to handle this is to
         * use two passes, but unfortunately, doing two passes makes parsing
         * code twice as slow.
         *
         * What we do is we set the inside state here, which overwrites whatever
         * __extra_match_condition() does.  Then we set the outside state in
         * __extra_pre_loop_hook_after().
         *
         */
        __push_fake_cur_stree();
        if (!loop->iterator_post_statement)
                ret = handle_canonical_while_count_down(loop);
        else
                ret = handle_canonical_for_loops(loop);
        *stree = __pop_fake_cur_stree();
        return ret;
}

int __iterator_unchanged(struct sm_state *sm)
{
        if (!sm)
                return 0;
        if (get_sm_state(my_id, sm->name, sm->sym) == sm)
                return 1;
        return 0;
}

static void while_count_down_after(struct sm_state *sm, struct expression *condition)
{
        struct expression *unop;
        int op;
        sval_t limit, after_value;

        if (!get_countdown_info(condition, &unop, &op, &limit))
                return;
        after_value = estate_min(sm->state);
        after_value.value--;
        set_extra_mod(sm->name, sm->sym, condition->unop, alloc_estate_sval(after_value));
}

void __extra_pre_loop_hook_after(struct sm_state *sm,
                                struct statement *iterator,
                                struct expression *condition)
{
        struct expression *iter_expr;
        sval_t limit;
        struct smatch_state *state;

        if (!iterator) {
                while_count_down_after(sm, condition);
                return;
        }

        iter_expr = iterator->expression;

        if (condition->type != EXPR_COMPARE)
                return;
        if (iter_expr->op == SPECIAL_INCREMENT) {
                limit = sval_binop(estate_max(sm->state), '+',
                                   sval_type_val(estate_type(sm->state), 1));
        } else {
                limit = sval_binop(estate_min(sm->state), '-',
                                   sval_type_val(estate_type(sm->state), 1));
        }
        limit = sval_cast(estate_type(sm->state), limit);
        if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
                if (iter_expr->op == SPECIAL_INCREMENT)
                        state = alloc_estate_range(estate_min(sm->state), limit);
                else
                        state = alloc_estate_range(limit, estate_max(sm->state));
        } else {
                state = alloc_estate_sval(limit);
        }
        if (!estate_has_hard_max(sm->state)) {
                estate_clear_hard_max(state);
        }
        if (estate_has_fuzzy_max(sm->state)) {
                sval_t hmax = estate_get_fuzzy_max(sm->state);
                sval_t max = estate_max(sm->state);

                if (sval_cmp(hmax, max) != 0)
                        estate_clear_fuzzy_max(state);
        } else if (!estate_has_fuzzy_max(sm->state)) {
                estate_clear_fuzzy_max(state);
        }

        set_extra_mod(sm->name, sm->sym, iter_expr, state);
}

static bool get_global_rl(const char *name, struct symbol *sym, struct range_list **rl)
{
        struct expression *expr;

        if (!sym || !(sym->ctype.modifiers & MOD_TOPLEVEL) || !sym->ident)
                return false;
        if (strcmp(sym->ident->name, name) != 0)
                return false;

        expr = symbol_expression(sym);
        return get_implied_rl(expr, rl);
}

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

        if (unmatched_stree) {
                state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
                if (state)
                        return state;
        }
        if (parent_is_gone_var_sym(sm->name, sm->sym))
                return alloc_estate_empty();
        if (get_global_rl(sm->name, sm->sym, &rl))
                return alloc_estate_rl(rl);
        return alloc_estate_whole(estate_type(sm->state));
}

static void clear_the_pointed_at(struct expression *expr)
{
        struct stree *stree;
        char *name;
        struct symbol *sym;
        struct sm_state *tmp;

        name = expr_to_var_sym(expr, &sym);
        if (!name || !sym)
                goto free;

        stree = __get_cur_stree();
        FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
                if (tmp->name[0] != '*')
                        continue;
                if (tmp->sym != sym)
                        continue;
                if (strcmp(tmp->name + 1, name) != 0)
                        continue;
                set_extra_mod(tmp->name, tmp->sym, expr, alloc_estate_whole(estate_type(tmp->state)));
        } END_FOR_EACH_SM(tmp);

free:
        free_string(name);
}

static int is_const_param(struct expression *expr, int param)
{
        struct symbol *type;

        type = get_arg_type(expr, param);
        if (!type)
                return 0;
        if (type->ctype.modifiers & MOD_CONST)
                return 1;
        return 0;
}

static void match_function_call(struct expression *expr)
{
        struct expression *arg;
        struct expression *tmp;
        int param = -1;

        /* if we have the db this is handled in smatch_function_hooks.c */
        if (!option_no_db)
                return;
        if (inlinable(expr->fn))
                return;

        FOR_EACH_PTR(expr->args, arg) {
                param++;
                if (is_const_param(expr->fn, param))
                        continue;
                tmp = strip_expr(arg);
                if (tmp->type == EXPR_PREOP && tmp->op == '&')
                        set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
                else
                        clear_the_pointed_at(tmp);
        } END_FOR_EACH_PTR(arg);
}

int values_fit_type(struct expression *left, struct expression *right)
{
        struct range_list *rl;
        struct symbol *type;

        type = get_type(left);
        if (!type)
                return 0;
        get_absolute_rl(right, &rl);
        if (type == rl_type(rl))
                return 1;
        if (type_unsigned(type) && sval_is_negative(rl_min(rl)))
                return 0;
        if (sval_cmp(sval_type_min(type), rl_min(rl)) > 0)
                return 0;
        if (sval_cmp(sval_type_max(type), rl_max(rl)) < 0)
                return 0;
        return 1;
}

static void save_chunk_info(struct expression *left, struct expression *right)
{
        struct var_sym_list *vsl;
        struct var_sym *vs;
        struct expression *add_expr;
        struct symbol *type;
        sval_t sval;
        char *name;
        struct symbol *sym;

        if (right->type != EXPR_BINOP || right->op != '-')
                return;
        if (!get_value(right->left, &sval))
                return;
        if (!expr_to_sym(right->right))
                return;

        add_expr = binop_expression(left, '+', right->right);
        type = get_type(add_expr);
        if (!type)
                return;
        name = expr_to_chunk_sym_vsl(add_expr, &sym, &vsl);
        if (!name || !vsl)
                goto free;
        FOR_EACH_PTR(vsl, vs) {
                store_link(link_id, vs->var, vs->sym, name, sym);
        } END_FOR_EACH_PTR(vs);

        set_state(SMATCH_EXTRA, name, sym, alloc_estate_sval(sval_cast(type, sval)));
free:
        free_string(name);
}

static void do_array_assign(struct expression *left, int op, struct expression *right)
{
        struct range_list *rl;

        if (op == '=') {
                get_absolute_rl(right, &rl);
                rl = cast_rl(get_type(left), rl);
        } else {
                rl = alloc_whole_rl(get_type(left));
        }

        set_extra_array_mod(left, alloc_estate_rl(rl));
}

static void match_vanilla_assign(struct expression *left, struct expression *right)
{
        struct range_list *orig_rl = NULL;
        struct range_list *rl = NULL;
        struct symbol *right_sym;
        struct symbol *left_type;
        struct symbol *right_type;
        char *right_name = NULL;
        struct symbol *sym;
        char *name;
        sval_t sval, max;
        struct smatch_state *state;
        int comparison;

        if (is_struct(left))
                return;

        save_chunk_info(left, right);

        name = expr_to_var_sym(left, &sym);
        if (!name) {
                if (chunk_has_array(left))
                        do_array_assign(left, '=', right);
                return;
        }

        left_type = get_type(left);
        right_type = get_type(right);

        right_name = expr_to_var_sym(right, &right_sym);

        if (!__in_fake_assign &&
            !(right->type == EXPR_PREOP && right->op == '&') &&
            right_name && right_sym &&
            values_fit_type(left, strip_expr(right)) &&
            !has_symbol(right, sym)) {
                set_equiv(left, right);
                goto free;
        }

        if (get_implied_value(right, &sval)) {
                state = alloc_estate_sval(sval_cast(left_type, sval));
                goto done;
        }

        if (__in_fake_assign) {
                struct smatch_state *right_state;
                sval_t sval;

                if (get_value(right, &sval)) {
                        sval = sval_cast(left_type, sval);
                        state = alloc_estate_sval(sval);
                        goto done;
                }

                right_state = get_state(SMATCH_EXTRA, right_name, right_sym);
                if (right_state) {
                        /* simple assignment */
                        state = clone_estate(right_state);
                        goto done;
                }

                state = alloc_estate_rl(alloc_whole_rl(left_type));
                goto done;
        }

        comparison = get_comparison_no_extra(left, right);
        if (comparison) {
                comparison = flip_comparison(comparison);
                get_implied_rl(left, &orig_rl);
        }

        if (get_implied_rl(right, &rl)) {
                rl = cast_rl(left_type, rl);
                if (orig_rl)
                        filter_by_comparison(&rl, comparison, orig_rl);
                state = alloc_estate_rl(rl);
                if (get_hard_max(right, &max)) {
                        estate_set_hard_max(state);
                        estate_set_fuzzy_max(state, max);
                }
        } else {
                rl = alloc_whole_rl(right_type);
                rl = cast_rl(left_type, rl);
                if (orig_rl)
                        filter_by_comparison(&rl, comparison, orig_rl);
                state = alloc_estate_rl(rl);
        }

done:
        set_extra_mod(name, sym, left, state);
free:
        free_string(right_name);
}

static void match_assign(struct expression *expr)
{
        struct range_list *rl = NULL;
        struct expression *left;
        struct expression *right;
        struct expression *binop_expr;
        struct symbol *left_type;
        struct symbol *sym;
        char *name;

        left = strip_expr(expr->left);

        right = strip_parens(expr->right);
        if (right->type == EXPR_CALL && sym_name_is("__builtin_expect", right->fn))
                right = get_argument_from_call_expr(right->args, 0);
        while (right->type == EXPR_ASSIGNMENT && right->op == '=')
                right = strip_parens(right->left);

        if (expr->op == '=' && is_condition(expr->right))
                return; /* handled in smatch_condition.c */
        if (expr->op == '=' && right->type == EXPR_CALL)
                return; /* handled in smatch_function_hooks.c */
        if (expr->op == '=') {
                match_vanilla_assign(left, right);
                return;
        }

        name = expr_to_var_sym(left, &sym);
        if (!name)
                return;

        left_type = get_type(left);

        switch (expr->op) {
        case SPECIAL_ADD_ASSIGN:
        case SPECIAL_SUB_ASSIGN:
        case SPECIAL_AND_ASSIGN:
        case SPECIAL_MOD_ASSIGN:
        case SPECIAL_SHL_ASSIGN:
        case SPECIAL_SHR_ASSIGN:
        case SPECIAL_OR_ASSIGN:
        case SPECIAL_XOR_ASSIGN:
        case SPECIAL_MUL_ASSIGN:
        case SPECIAL_DIV_ASSIGN:
                binop_expr = binop_expression(expr->left,
                                              op_remove_assign(expr->op),
                                              expr->right);
                get_absolute_rl(binop_expr, &rl);
                rl = cast_rl(left_type, rl);
                if (inside_loop()) {
                        if (expr->op == SPECIAL_ADD_ASSIGN)
                                add_range(&rl, rl_max(rl), sval_type_max(rl_type(rl)));

                        if (expr->op == SPECIAL_SUB_ASSIGN &&
                            !sval_is_negative(rl_min(rl))) {
                                sval_t zero = { .type = rl_type(rl) };

                                add_range(&rl, rl_min(rl), zero);
                        }
                }
                set_extra_mod(name, sym, left, alloc_estate_rl(rl));
                goto free;
        }
        set_extra_mod(name, sym, left, alloc_estate_whole(left_type));
free:
        free_string(name);
}

static struct smatch_state *increment_state(struct smatch_state *state)
{
        sval_t min = estate_min(state);
        sval_t max = estate_max(state);

        if (!estate_rl(state))
                return NULL;

        if (inside_loop())
                max = sval_type_max(max.type);

        if (!sval_is_min(min) && !sval_is_max(min))
                min.value++;
        if (!sval_is_min(max) && !sval_is_max(max))
                max.value++;
        return alloc_estate_range(min, max);
}

static struct smatch_state *decrement_state(struct smatch_state *state)
{
        sval_t min = estate_min(state);
        sval_t max = estate_max(state);

        if (!estate_rl(state))
                return NULL;

        if (inside_loop())
                min = sval_type_min(min.type);

        if (!sval_is_min(min) && !sval_is_max(min))
                min.value--;
        if (!sval_is_min(max) && !sval_is_max(max))
                max.value--;
        return alloc_estate_range(min, max);
}

static void clear_pointed_at_state(struct expression *expr)
{
        struct symbol *type;

        /*
         * ALERT: This is sort of a mess.  If it's is a struct assigment like
         * "foo = bar;", then that's handled by smatch_struct_assignment.c.
         * the same thing for p++ where "p" is a struct.  Most modifications
         * are handled by the assignment hook or the db.  Smatch_extra.c doesn't
         * use smatch_modification.c because we have to get the ordering right
         * or something.  So if you have p++ where p is a pointer to a standard
         * c type then we handle that here.  What a mess.
         */
        expr = strip_expr(expr);
        type = get_type(expr);
        if (!type || type->type != SYM_PTR)
                return;
        type = get_real_base_type(type);
        if (!type || type->type != SYM_BASETYPE)
                return;
        set_extra_expr_nomod(deref_expression(expr), alloc_estate_whole(type));
}

static void unop_expr(struct expression *expr)
{
        struct smatch_state *state;

        if (expr->smatch_flags & Handled)
                return;

        switch (expr->op) {
        case SPECIAL_INCREMENT:
                state = get_state_expr(SMATCH_EXTRA, expr->unop);
                state = increment_state(state);
                if (!state)
                        state = alloc_estate_whole(get_type(expr));
                set_extra_expr_mod(expr->unop, state);
                clear_pointed_at_state(expr->unop);
                break;
        case SPECIAL_DECREMENT:
                state = get_state_expr(SMATCH_EXTRA, expr->unop);
                state = decrement_state(state);
                if (!state)
                        state = alloc_estate_whole(get_type(expr));
                set_extra_expr_mod(expr->unop, state);
                clear_pointed_at_state(expr->unop);
                break;
        default:
                return;
        }
}

static void asm_expr(struct statement *stmt)
{

        struct expression *expr;
        struct symbol *type;

        FOR_EACH_PTR(stmt->asm_outputs, expr) {
                if (expr->type != EXPR_ASM_OPERAND) {
                        sm_perror("unexpected asm param type %d", expr->type);
                        continue;
                }
                type = get_type(strip_expr(expr->expr));
                set_extra_expr_mod(expr->expr, alloc_estate_whole(type));
        } END_FOR_EACH_PTR(expr);
}

static void check_dereference(struct expression *expr)
{
        struct smatch_state *state;

        if (__in_fake_assign)
                return;
        if (outside_of_function())
                return;
        state = get_extra_state(expr);
        if (state) {
                struct range_list *rl;

                rl = rl_intersection(estate_rl(state), valid_ptr_rl);
                if (rl_equiv(rl, estate_rl(state)))
                        return;
                set_extra_expr_nomod(expr, alloc_estate_rl(rl));
        } else {
                struct range_list *rl;

                if (get_mtag_rl(expr, &rl))
                        rl = rl_intersection(rl, valid_ptr_rl);
                else
                        rl = clone_rl(valid_ptr_rl);

                set_extra_expr_nomod(expr, alloc_estate_rl(rl));
        }
}

static void match_dereferences(struct expression *expr)
{
        if (expr->type != EXPR_PREOP)
                return;
        if (getting_address(expr))
                return;
        /* it's saying that foo[1] = bar dereferences foo[1] */
        if (is_array(expr))
                return;
        check_dereference(expr->unop);
}

static void match_pointer_as_array(struct expression *expr)
{
        if (!is_array(expr))
                return;
        check_dereference(get_array_base(expr));
}

static void find_dereferences(struct expression *expr)
{
        while (expr->type == EXPR_PREOP) {
                if (expr->op == '*')
                        check_dereference(expr->unop);
                expr = strip_expr(expr->unop);
        }
}

static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused)
{
        struct symbol *sym;
        char *name;

        name = get_variable_from_key(arg, key, &sym);
        if (name && sym) {
                struct smatch_state *orig, *new;
                struct range_list *rl;

                orig = get_state(SMATCH_EXTRA, name, sym);
                if (orig) {
                        rl = rl_intersection(estate_rl(orig),
                                             alloc_rl(valid_ptr_min_sval,
                                                      valid_ptr_max_sval));
                        new = alloc_estate_rl(rl);
                } else {
                        new = alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval);
                }

                set_extra_nomod(name, sym, NULL, new);
        }
        free_string(name);

        find_dereferences(arg);
}

static sval_t add_one(sval_t sval)
{
        sval.value++;
        return sval;
}

static int handle_postop_inc(struct expression *left, int op, struct expression *right)
{
        struct statement *stmt;
        struct expression *cond;
        struct smatch_state *true_state, *false_state;
        struct symbol *type;
        sval_t start;
        sval_t limit;

        /*
         * If we're decrementing here then that's a canonical while count down
         * so it's handled already.  We're only handling loops like:
         * i = 0;
         * do { ... } while (i++ < 3);
         */

        if (left->type != EXPR_POSTOP || left->op != SPECIAL_INCREMENT)
                return 0;

        stmt = __cur_stmt->parent;
        if (!stmt)
                return 0;
        if (stmt->type == STMT_COMPOUND)
                stmt = stmt->parent;
        if (!stmt || stmt->type != STMT_ITERATOR || !stmt->iterator_post_condition)
                return 0;

        cond = strip_expr(stmt->iterator_post_condition);
        if (cond->type != EXPR_COMPARE || cond->op != op)
                return 0;
        if (left != strip_expr(cond->left) || right != strip_expr(cond->right))
                return 0;

        if (!get_implied_value(left->unop, &start))
                return 0;
        if (!get_implied_value(right, &limit))
                return 0;
        type = get_type(left->unop);
        limit = sval_cast(type, limit);
        if (sval_cmp(start, limit) > 0)
                return 0;

        switch (op) {
        case '<':
        case SPECIAL_UNSIGNED_LT:
                break;
        case SPECIAL_LTE:
        case SPECIAL_UNSIGNED_LTE:
                limit = add_one(limit);
        default:
                return 0;

        }

        true_state = alloc_estate_range(add_one(start), limit);
        false_state = alloc_estate_range(add_one(limit), add_one(limit));

        /* Currently we just discard the false state but when two passes is
         * implimented correctly then it will use it.
         */

        set_extra_expr_true_false(left->unop, true_state, false_state);

        return 1;
}

bool is_impossible_variable(struct expression *expr)
{
        struct smatch_state *state;

        state = get_extra_state(expr);
        if (state && !estate_rl(state))
                return true;
        return false;
}

static bool in_macro(struct expression *left, struct expression *right)
{
        if (!left || !right)
                return 0;
        if (left->pos.line != right->pos.line || left->pos.pos != right->pos.pos)
                return 0;
        if (get_macro_name(left->pos))
                return 1;
        return 0;
}

static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
{
        struct range_list *left_orig;
        struct range_list *left_true;
        struct range_list *left_false;
        struct range_list *right_orig;
        struct range_list *right_true;
        struct range_list *right_false;
        struct smatch_state *left_true_state;
        struct smatch_state *left_false_state;
        struct smatch_state *right_true_state;
        struct smatch_state *right_false_state;
        sval_t dummy, hard_max;
        int left_postop = 0;
        int right_postop = 0;

        if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
                if (left->type == EXPR_POSTOP) {
                        left->smatch_flags |= Handled;
                        left_postop = left->op;
                        if (handle_postop_inc(left, op, right))
                                return;
                }
                left = strip_parens(left->unop);
        }
        while (left->type == EXPR_ASSIGNMENT)
                left = strip_parens(left->left);

        if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
                if (right->type == EXPR_POSTOP) {
                        right->smatch_flags |= Handled;
                        right_postop = right->op;
                }
                right = strip_parens(right->unop);
        }

        if (is_impossible_variable(left) || is_impossible_variable(right))
                return;

        get_real_absolute_rl(left, &left_orig);
        left_orig = cast_rl(type, left_orig);

        get_real_absolute_rl(right, &right_orig);
        right_orig = cast_rl(type, right_orig);

        split_comparison_rl(left_orig, op, right_orig, &left_true, &left_false, &right_true, &right_false);

        left_true = rl_truncate_cast(get_type(strip_expr(left)), left_true);
        left_false = rl_truncate_cast(get_type(strip_expr(left)), left_false);
        right_true = rl_truncate_cast(get_type(strip_expr(right)), right_true);
        right_false = rl_truncate_cast(get_type(strip_expr(right)), right_false);

        if (!left_true || !left_false) {
                struct range_list *tmp_true, *tmp_false;

                split_comparison_rl(alloc_whole_rl(type), op, right_orig, &tmp_true, &tmp_false, NULL, NULL);
                tmp_true = rl_truncate_cast(get_type(strip_expr(left)), tmp_true);
                tmp_false = rl_truncate_cast(get_type(strip_expr(left)), tmp_false);
                if (tmp_true && tmp_false)
                        __save_imaginary_state(left, tmp_true, tmp_false);
        }

        if (!right_true || !right_false) {
                struct range_list *tmp_true, *tmp_false;

                split_comparison_rl(alloc_whole_rl(type), op, right_orig, NULL, NULL, &tmp_true, &tmp_false);
                tmp_true = rl_truncate_cast(get_type(strip_expr(right)), tmp_true);
                tmp_false = rl_truncate_cast(get_type(strip_expr(right)), tmp_false);
                if (tmp_true && tmp_false)
                        __save_imaginary_state(right, tmp_true, tmp_false);
        }

        left_true_state = alloc_estate_rl(left_true);
        left_false_state = alloc_estate_rl(left_false);
        right_true_state = alloc_estate_rl(right_true);
        right_false_state = alloc_estate_rl(right_false);

        switch (op) {
        case '<':
        case SPECIAL_UNSIGNED_LT:
        case SPECIAL_UNSIGNED_LTE:
        case SPECIAL_LTE:
                if (get_implied_value(right, &dummy) && !in_macro(left, right))
                        estate_set_hard_max(left_true_state);
                if (get_implied_value(left, &dummy) && !in_macro(left, right))
                        estate_set_hard_max(right_false_state);
                break;
        case '>':
        case SPECIAL_UNSIGNED_GT:
        case SPECIAL_UNSIGNED_GTE:
        case SPECIAL_GTE:
                if (get_implied_value(left, &dummy) && !in_macro(left, right))
                        estate_set_hard_max(right_true_state);
                if (get_implied_value(right, &dummy) && !in_macro(left, right))
                        estate_set_hard_max(left_false_state);
                break;
        }

        switch (op) {
        case '<':
        case SPECIAL_UNSIGNED_LT:
        case SPECIAL_UNSIGNED_LTE:
        case SPECIAL_LTE:
                if (get_hard_max(right, &hard_max)) {
                        if (op == '<' || op == SPECIAL_UNSIGNED_LT)
                                hard_max.value--;
                        estate_set_fuzzy_max(left_true_state, hard_max);
                }
                if (get_implied_value(right, &hard_max)) {
                        if (op == SPECIAL_UNSIGNED_LTE ||
                            op == SPECIAL_LTE)
                                hard_max.value++;
                        estate_set_fuzzy_max(left_false_state, hard_max);
                }
                if (get_hard_max(left, &hard_max)) {
                        if (op == SPECIAL_UNSIGNED_LTE ||
                            op == SPECIAL_LTE)
                                hard_max.value--;
                        estate_set_fuzzy_max(right_false_state, hard_max);
                }
                if (get_implied_value(left, &hard_max)) {
                        if (op == '<' || op == SPECIAL_UNSIGNED_LT)
                                hard_max.value++;
                        estate_set_fuzzy_max(right_true_state, hard_max);
                }
                break;
        case '>':
        case SPECIAL_UNSIGNED_GT:
        case SPECIAL_UNSIGNED_GTE:
        case SPECIAL_GTE:
                if (get_hard_max(left, &hard_max)) {
                        if (op == '>' || op == SPECIAL_UNSIGNED_GT)
                                hard_max.value--;
                        estate_set_fuzzy_max(right_true_state, hard_max);
                }
                if (get_implied_value(left, &hard_max)) {
                        if (op == SPECIAL_UNSIGNED_GTE ||
                            op == SPECIAL_GTE)
                                hard_max.value++;
                        estate_set_fuzzy_max(right_false_state, hard_max);
                }
                if (get_hard_max(right, &hard_max)) {
                        if (op == SPECIAL_UNSIGNED_LTE ||
                            op == SPECIAL_LTE)
                                hard_max.value--;
                        estate_set_fuzzy_max(left_false_state, hard_max);
                }
                if (get_implied_value(right, &hard_max)) {
                        if (op == '>' ||
                            op == SPECIAL_UNSIGNED_GT)
                                hard_max.value++;
                        estate_set_fuzzy_max(left_true_state, hard_max);
                }
                break;
        case SPECIAL_EQUAL:
                if (get_hard_max(left, &hard_max))
                        estate_set_fuzzy_max(right_true_state, hard_max);
                if (get_hard_max(right, &hard_max))
                        estate_set_fuzzy_max(left_true_state, hard_max);
                break;
        }

        if (get_hard_max(left, &hard_max)) {
                estate_set_hard_max(left_true_state);
                estate_set_hard_max(left_false_state);
        }
        if (get_hard_max(right, &hard_max)) {
                estate_set_hard_max(right_true_state);
                estate_set_hard_max(right_false_state);
        }

        if (left_postop == SPECIAL_INCREMENT) {
                left_true_state = increment_state(left_true_state);
                left_false_state = increment_state(left_false_state);
        }
        if (left_postop == SPECIAL_DECREMENT) {
                left_true_state = decrement_state(left_true_state);
                left_false_state = decrement_state(left_false_state);
        }
        if (right_postop == SPECIAL_INCREMENT) {
                right_true_state = increment_state(right_true_state);
                right_false_state = increment_state(right_false_state);
        }
        if (right_postop == SPECIAL_DECREMENT) {
                right_true_state = decrement_state(right_true_state);
                right_false_state = decrement_state(right_false_state);
        }

        if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
                left_true_state = NULL;
                left_false_state = NULL;
        }

        if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
                right_true_state = NULL;
                right_false_state = NULL;
        }

        /* Don't introduce new states for known true/false conditions */
        if (rl_equiv(left_orig, estate_rl(left_true_state)))
                left_true_state = NULL;
        if (rl_equiv(left_orig, estate_rl(left_false_state)))
                left_false_state = NULL;
        if (rl_equiv(right_orig, estate_rl(right_true_state)))
                right_true_state = NULL;
        if (rl_equiv(right_orig, estate_rl(right_false_state)))
                right_false_state = NULL;

        set_extra_expr_true_false(left, left_true_state, left_false_state);
        set_extra_expr_true_false(right, right_true_state, right_false_state);
}

static int is_simple_math(struct expression *expr)
{
        if (!expr)
                return 0;
        if (expr->type != EXPR_BINOP)
                return 0;
        switch (expr->op) {
        case '+':
        case '-':
        case '*':
                return 1;
        }
        return 0;
}

static int flip_op(int op)
{
        /* We only care about simple math */
        switch (op) {
        case '+':
                return '-';
        case '-':
                return '+';
        case '*':
                return '/';
        }
        return 0;
}

static void move_known_to_rl(struct expression **expr_p, struct range_list **rl_p)
{
        struct expression *expr = *expr_p;
        struct range_list *rl = *rl_p;
        sval_t sval;

        if (!is_simple_math(expr))
                return;

        if (get_implied_value(expr->right, &sval)) {
                *expr_p = expr->left;
                *rl_p = rl_binop(rl, flip_op(expr->op), alloc_rl(sval, sval));
                move_known_to_rl(expr_p, rl_p);
                return;
        }
        if (expr->op == '-')
                return;
        if (get_implied_value(expr->left, &sval)) {
                *expr_p = expr->right;
                *rl_p = rl_binop(rl, flip_op(expr->op), alloc_rl(sval, sval));
                move_known_to_rl(expr_p, rl_p);
                return;
        }
}

static void move_known_values(struct expression **left_p, struct expression **right_p)
{
        struct expression *left = *left_p;
        struct expression *right = *right_p;
        sval_t sval, dummy;

        if (get_implied_value(left, &sval)) {
                if (!is_simple_math(right))
                        return;
                if (get_implied_value(right, &dummy))
                        return;
                if (right->op == '*') {
                        sval_t divisor;

                        if (!get_value(right->right, &divisor))
                                return;
                        if (divisor.value == 0)
                                return;
                        *left_p = binop_expression(left, invert_op(right->op), right->right);
                        *right_p = right->left;
                        return;
                }
                if (right->op == '+' && get_value(right->left, &sval)) {
                        *left_p = binop_expression(left, invert_op(right->op), right->left);
                        *right_p = right->right;
                        return;
                }
                if (get_value(right->right, &sval)) {
                        *left_p = binop_expression(left, invert_op(right->op), right->right);
                        *right_p = right->left;
                        return;
                }
                return;
        }
        if (get_implied_value(right, &sval)) {
                if (!is_simple_math(left))
                        return;
                if (get_implied_value(left, &dummy))
                        return;
                if (left->op == '*') {
                        sval_t divisor;

                        if (!get_value(left->right, &divisor))
                                return;
                        if (divisor.value == 0)
                                return;
                        *right_p = binop_expression(right, invert_op(left->op), left->right);
                        *left_p = left->left;
                        return;
                }
                if (left->op == '+' && get_value(left->left, &sval)) {
                        *right_p = binop_expression(right, invert_op(left->op), left->left);
                        *left_p = left->right;
                        return;
                }

                if (get_value(left->right, &sval)) {
                        *right_p = binop_expression(right, invert_op(left->op), left->right);
                        *left_p = left->left;
                        return;
                }
                return;
        }
}

/*
 * The reason for do_simple_algebra() is to solve things like:
 * if (foo > 66 || foo + bar > 64) {
 * "foo" is not really a known variable so it won't be handled by
 * move_known_variables() but it's a super common idiom.
 *
 */
static int do_simple_algebra(struct expression **left_p, struct expression **right_p)
{
        struct expression *left = *left_p;
        struct expression *right = *right_p;
        struct range_list *rl;
        sval_t tmp;

        if (left->type != EXPR_BINOP || left->op != '+')
                return 0;
        if (can_integer_overflow(get_type(left), left))
                return 0;
        if (!get_implied_value(right, &tmp))
                return 0;

        if (!get_implied_value(left->left, &tmp) &&
            get_implied_rl(left->left, &rl) &&
            !is_whole_rl(rl)) {
                *right_p = binop_expression(right, '-', left->left);
                *left_p = left->right;
                return 1;
        }
        if (!get_implied_value(left->right, &tmp) &&
            get_implied_rl(left->right, &rl) &&
            !is_whole_rl(rl)) {
                *right_p = binop_expression(right, '-', left->right);
                *left_p = left->left;
                return 1;
        }

        return 0;
}

static int match_func_comparison(struct expression *expr)
{
        struct expression *left = strip_expr(expr->left);
        struct expression *right = strip_expr(expr->right);

        if (left->type == EXPR_CALL || right->type == EXPR_CALL) {
                function_comparison(left, expr->op, right);
                return 1;
        }

        return 0;
}

/* Handle conditions like "if (foo + bar < foo) {" */
static int handle_integer_overflow_test(struct expression *expr)
{
        struct expression *left, *right;
        struct symbol *type;
        sval_t left_min, right_min, min, max;

        if (expr->op != '<' && expr->op != SPECIAL_UNSIGNED_LT)
                return 0;

        left = strip_parens(expr->left);
        right = strip_parens(expr->right);

        if (left->op != '+')
                return 0;

        type = get_type(expr);
        if (!type)
                return 0;
        if (type_positive_bits(type) == 32) {
                max.type = &uint_ctype;
                max.uvalue = (unsigned int)-1;
        } else if (type_positive_bits(type) == 64) {
                max.type = &ulong_ctype;
                max.value = (unsigned long long)-1;
        } else {
                return 0;
        }

        if (!expr_equiv(left->left, right) && !expr_equiv(left->right, right))
                return 0;

        get_absolute_min(left->left, &left_min);
        get_absolute_min(left->right, &right_min);
        min = sval_binop(left_min, '+', right_min);

        type = get_type(left);
        min = sval_cast(type, min);
        max = sval_cast(type, max);

        set_extra_chunk_true_false(left, NULL, alloc_estate_range(min, max));
        return 1;
}

static void match_comparison(struct expression *expr)
{
        struct expression *left_orig = strip_parens(expr->left);
        struct expression *right_orig = strip_parens(expr->right);
        struct expression *left, *right, *tmp;
        struct expression *prev;
        struct symbol *type;
        int redo, count;

        if (match_func_comparison(expr))
                return;

        type = get_type(expr);
        if (!type)
                type = &llong_ctype;

        if (handle_integer_overflow_test(expr))
                return;

        left = left_orig;
        right = right_orig;
        move_known_values(&left, &right);
        handle_comparison(type, left, expr->op, right);

        left = left_orig;
        right = right_orig;
        if (do_simple_algebra(&left, &right))
                handle_comparison(type, left, expr->op, right);

        prev = get_assigned_expr(left_orig);
        if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
                left = prev;
                right = right_orig;
                move_known_values(&left, &right);
                handle_comparison(type, left, expr->op, right);
        }

        prev = get_assigned_expr(right_orig);
        if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
                left = left_orig;
                right = prev;
                move_known_values(&left, &right);
                handle_comparison(type, left, expr->op, right);
        }

        redo = 0;
        left = left_orig;
        right = right_orig;
        if (get_last_expr_from_expression_stmt(left_orig)) {
                left = get_last_expr_from_expression_stmt(left_orig);
                redo = 1;
        }
        if (get_last_expr_from_expression_stmt(right_orig)) {
                right = get_last_expr_from_expression_stmt(right_orig);
                redo = 1;
        }

        if (!redo)
                return;

        count = 0;
        while ((tmp = get_assigned_expr(left))) {
                if (count++ > 3)
                        break;
                left = strip_expr(tmp);
        }
        count = 0;
        while ((tmp = get_assigned_expr(right))) {
                if (count++ > 3)
                        break;
                right = strip_expr(tmp);
        }

        handle_comparison(type, left, expr->op, right);
}

static sval_t get_high_mask(sval_t known)
{
        sval_t ret;
        int i;

        ret = known;
        ret.value = 0;

        for (i = type_bits(known.type) - 1; i >= 0; i--) {
                if (known.uvalue & (1ULL << i))
                        ret.uvalue |= (1ULL << i);
                else
                        return ret;

        }
        return ret;
}

static bool handle_bit_test(struct expression *expr)
{
        struct range_list *orig_rl, *rl;
        struct expression *shift, *mask, *var;
        struct bit_info *bit_info;
        sval_t sval;
        sval_t high = { .type = &int_ctype };
        sval_t low = { .type = &int_ctype };

        shift = strip_expr(expr->right);
        mask = strip_expr(expr->left);
        if (shift->type != EXPR_BINOP || shift->op != SPECIAL_LEFTSHIFT) {
                shift = strip_expr(expr->left);
                mask = strip_expr(expr->right);
                if (shift->type != EXPR_BINOP || shift->op != SPECIAL_LEFTSHIFT)
                        return false;
        }
        if (!get_implied_value(shift->left, &sval) || sval.value != 1)
                return false;
        var = strip_expr(shift->right);

        bit_info = get_bit_info(mask);
        if (!bit_info)
                return false;
        if (!bit_info->possible)
                return false;

        get_absolute_rl(var, &orig_rl);
        if (sval_is_negative(rl_min(orig_rl)) ||
            rl_max(orig_rl).uvalue > type_bits(get_type(shift->left)))
                return false;

        low.value = ffsll(bit_info->possible);
        high.value = sm_fls64(bit_info->possible);
        rl = alloc_rl(low, high);
        rl = cast_rl(get_type(var), rl);
        rl = rl_intersection(orig_rl, rl);
        if (!rl)
                return false;

        set_extra_expr_true_false(shift->right, alloc_estate_rl(rl), NULL);

        return true;
}

static void handle_AND_op(struct expression *var, sval_t known)
{
        struct range_list *orig_rl;
        struct range_list *true_rl = NULL;
        struct range_list *false_rl = NULL;
        int bit;
        sval_t low_mask = known;
        sval_t high_mask;
        sval_t max;

        get_absolute_rl(var, &orig_rl);

        if (known.value > 0) {
                bit = ffsll(known.value) - 1;
                low_mask.uvalue = (1ULL << bit) - 1;
                true_rl = remove_range(orig_rl, sval_type_val(known.type, 0), low_mask);
        }
        high_mask = get_high_mask(known);
        if (high_mask.value) {
                bit = ffsll(high_mask.value) - 1;
                low_mask.uvalue = (1ULL << bit) - 1;

                false_rl = orig_rl;
                if (sval_is_negative(rl_min(orig_rl)))
                        false_rl = remove_range(false_rl, sval_type_min(known.type), sval_type_val(known.type, -1));
                false_rl = remove_range(false_rl, low_mask, sval_type_max(known.type));
                if (type_signed(high_mask.type) && type_unsigned(rl_type(false_rl))) {
                        false_rl = remove_range(false_rl,
                                                sval_type_val(rl_type(false_rl), sval_type_max(known.type).uvalue),
                                        sval_type_val(rl_type(false_rl), -1));
                }
        } else if (known.value == 1 &&
                   get_hard_max(var, &max) &&
                   sval_cmp(max, rl_max(orig_rl)) == 0 &&
                   max.value & 1) {
                false_rl = remove_range(orig_rl, max, max);
        }
        set_extra_expr_true_false(var,
                                  true_rl ? alloc_estate_rl(true_rl) : NULL,
                                  false_rl ? alloc_estate_rl(false_rl) : NULL);
}

static void handle_AND_condition(struct expression *expr)
{
        sval_t known;

        if (handle_bit_test(expr))
                return;

        if (get_implied_value(expr->left, &known))
                handle_AND_op(expr->right, known);
        else if (get_implied_value(expr->right, &known))
                handle_AND_op(expr->left, known);
}

static void handle_MOD_condition(struct expression *expr)
{
        struct range_list *orig_rl;
        struct range_list *true_rl;
        struct range_list *false_rl = NULL;
        sval_t right;
        sval_t zero = { 0, };

        if (!get_implied_value(expr->right, &right) || right.value == 0)
                return;
        get_absolute_rl(expr->left, &orig_rl);

        zero.value = 0;
        zero.type = rl_type(orig_rl);

        /* We're basically dorking around the min and max here */
        true_rl = remove_range(orig_rl, zero, zero);
        if (!sval_is_max(rl_max(true_rl)) &&
            !(rl_max(true_rl).value % right.value))
                true_rl = remove_range(true_rl, rl_max(true_rl), rl_max(true_rl));

        if (rl_equiv(true_rl, orig_rl))
                true_rl = NULL;

        if (sval_is_positive(rl_min(orig_rl)) &&
            (rl_max(orig_rl).value - rl_min(orig_rl).value) / right.value < 5) {
                sval_t add;
                int i;

                add = rl_min(orig_rl);
                add.value += right.value - (add.value % right.value);
                add.value -= right.value;

                for (i = 0; i < 5; i++) {
                        add.value += right.value;
                        if (add.value > rl_max(orig_rl).value)
                                break;
                        add_range(&false_rl, add, add);
                }
        } else {
                if (rl_min(orig_rl).uvalue != 0 &&
                    rl_min(orig_rl).uvalue < right.uvalue) {
                        sval_t chop = right;
                        chop.value--;
                        false_rl = remove_range(orig_rl, zero, chop);
                }

                if (!sval_is_max(rl_max(orig_rl)) &&
                    (rl_max(orig_rl).value % right.value)) {
                        sval_t chop = rl_max(orig_rl);
                        chop.value -= chop.value % right.value;
                        chop.value++;
                        if (!false_rl)
                                false_rl = clone_rl(orig_rl);
                        false_rl = remove_range(false_rl, chop, rl_max(orig_rl));
                }
        }

        set_extra_expr_true_false(expr->left,
                                  true_rl ? alloc_estate_rl(true_rl) : NULL,
                                  false_rl ? alloc_estate_rl(false_rl) : NULL);
}

/* this is actually hooked from smatch_implied.c...  it's hacky, yes */
void __extra_match_condition(struct expression *expr)
{
        expr = strip_expr(expr);
        switch (expr->type) {
        case EXPR_CALL:
                function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
                return;
        case EXPR_PREOP:
        case EXPR_SYMBOL:
        case EXPR_DEREF:
                handle_comparison(get_type(expr), expr, SPECIAL_NOTEQUAL, zero_expr());
                return;
        case EXPR_COMPARE:
                match_comparison(expr);
                return;
        case EXPR_ASSIGNMENT:
                __extra_match_condition(expr->left);
                return;
        case EXPR_BINOP:
                if (expr->op == '&')
                        handle_AND_condition(expr);
                if (expr->op == '%')
                        handle_MOD_condition(expr);
                return;
        }
}

static void assume_indexes_are_valid(struct expression *expr)
{
        struct expression *array_expr;
        int array_size;
        struct expression *offset;
        struct symbol *offset_type;
        struct range_list *rl_before;
        struct range_list *rl_after;
        struct range_list *filter = NULL;
        sval_t size;

        expr = strip_expr(expr);
        if (!is_array(expr))
                return;

        offset = get_array_offset(expr);
        offset_type = get_type(offset);
        if (offset_type && type_signed(offset_type)) {
                filter = alloc_rl(sval_type_min(offset_type),
                                  sval_type_val(offset_type, -1));
        }

        array_expr = get_array_base(expr);
        array_size = get_real_array_size(array_expr);
        if (array_size > 1) {
                size = sval_type_val(offset_type, array_size);
                add_range(&filter, size, sval_type_max(offset_type));
        }

        if (!filter)
                return;
        get_absolute_rl(offset, &rl_before);
        rl_after = rl_filter(rl_before, filter);
        if (rl_equiv(rl_before, rl_after))
                return;
        set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
}

/* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
int implied_not_equal(struct expression *expr, long long val)
{
        return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
}

int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
{
        struct smatch_state *estate;

        estate = get_state(SMATCH_EXTRA, name, sym);
        if (!estate)
                return 0;
        if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
                return 1;
        return 0;
}

int parent_is_null_var_sym(const char *name, struct symbol *sym)
{
        char buf[256];
        char *start;
        char *end;
        struct smatch_state *state;

        strncpy(buf, name, sizeof(buf) - 1);
        buf[sizeof(buf) - 1] = '\0';

        start = &buf[0];
        while (*start == '*') {
                start++;
                state = __get_state(SMATCH_EXTRA, start, sym);
                if (!state)
                        continue;
                if (!estate_rl(state))
                        return 1;
                if (estate_min(state).value == 0 &&
                    estate_max(state).value == 0)
                        return 1;
        }

        start = &buf[0];
        while (*start == '&')
                start++;

        while ((end = strrchr(start, '-'))) {
                *end = '\0';
                state = __get_state(SMATCH_EXTRA, start, sym);
                if (!state)
                        continue;
                if (estate_min(state).value == 0 &&
                    estate_max(state).value == 0)
                        return 1;
        }
        return 0;
}

int parent_is_null(struct expression *expr)
{
        struct symbol *sym;
        char *var;
        int ret = 0;

        expr = strip_expr(expr);
        var = expr_to_var_sym(expr, &sym);
        if (!var || !sym)
                goto free;
        ret = parent_is_null_var_sym(var, sym);
free:
        free_string(var);
        return ret;
}

static int param_used_callback(void *found, int argc, char **argv, char **azColName)
{
        *(int *)found = 1;
        return 0;
}

static int is_kzalloc_info(struct sm_state *sm)
{
        sval_t sval;

        /*
         * kzalloc() information is treated as special because so there is just
         * a lot of stuff initialized to zero and it makes building the database
         * take hours and hours.
         *
         * In theory, we should just remove this line and not pass any unused
         * information, but I'm not sure enough that this code works so I want
         * to hold off on that for now.
         */
        if (!estate_get_single_value(sm->state, &sval))
                return 0;
        if (sval.value != 0)
                return 0;
        return 1;
}

static int is_really_long(struct sm_state *sm)
{
        const char *p;
        int cnt = 0;

        p = sm->name;
        while ((p = strstr(p, "->"))) {
                p += 2;
                cnt++;
        }

        if (cnt < 3 ||
            strlen(sm->name) < 40)
                return 0;
        return 1;
}

static int filter_unused_param_value_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
{
        int found = 0;

        /* for function pointers assume everything is used */
        if (call->fn->type != EXPR_SYMBOL)
                return 0;

        /*
         * This is to handle __builtin_mul_overflow().  In an ideal world we
         * would only need this for invalid code.
         *
         */
        if (!call->fn->symbol)
                return 0;

        if (!is_kzalloc_info(sm) && !is_really_long(sm))
                return 0;

        run_sql(&param_used_callback, &found,
                "select * from return_implies where %s and type = %d and parameter = %d and key = '%s';",
                get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
        if (found)
                return 0;

        /* If the database is not built yet, then assume everything is used */
        run_sql(&param_used_callback, &found,
                "select * from return_implies where %s and type = %d;",
                get_static_filter(call->fn->symbol), PARAM_USED);
        if (!found)
                return 0;

        return 1;
}

struct range_list *intersect_with_real_abs_var_sym(const char *name, struct symbol *sym, struct range_list *start)
{
        struct smatch_state *state;

        /*
         * Here is the difference between implied value and real absolute, say
         * you have:
         *
         *      int a = (u8)x;
         *
         * Then you know that a is 0-255.  That's real absolute.  But you don't
         * know for sure that it actually goes up to 255.  So it's not implied.
         * Implied indicates a degree of certainty.
         *
         * But then say you cap "a" at 8.  That means you know it goes up to
         * 8.  So now the implied value is s32min-8.  But you can combine it
         * with the real absolute to say that actually it's 0-8.
         *
         * We are combining it here.  But now that I think about it, this is
         * probably not the ideal place to combine it because it should proably
         * be done earlier.  Oh well, this is an improvement on what was there
         * before so I'm going to commit this code.
         *
         */

        state = get_real_absolute_state_var_sym(name, sym);
        if (!state || !estate_rl(state))
                return start;

        return rl_intersection(estate_rl(state), start);
}

struct range_list *intersect_with_real_abs_expr(struct expression *expr, struct range_list *start)
{
        struct smatch_state *state;
        struct range_list *abs_rl;

        state = get_real_absolute_state(expr);
        if (!state || !estate_rl(state))
                return start;

        abs_rl = cast_rl(rl_type(start), estate_rl(state));
        return rl_intersection(abs_rl, start);
}

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

        if (estate_is_whole(sm->state) || !estate_rl(sm->state))
                return;
        if (filter_unused_param_value_info(call, param, printed_name, sm))
                return;
        rl = estate_rl(sm->state);
        rl = intersect_with_real_abs_var_sym(sm->name, sm->sym, rl);
        if (!rl)
                return;
        sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, show_rl(rl));
        if (!estate_get_single_value(sm->state, &dummy)) {
                if (estate_has_hard_max(sm->state))
                        sql_insert_caller_info(call, HARD_MAX, param, printed_name,
                                               sval_to_str(estate_max(sm->state)));
                if (estate_has_fuzzy_max(sm->state))
                        sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
                                               sval_to_str(estate_get_fuzzy_max(sm->state)));
        }
}

static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
{
        struct symbol *returned_sym;
        char *returned_name;
        struct sm_state *sm;
        char *compare_str;
        char name_buf[256];
        char val_buf[256];
        int len;

        // FIXME handle *$

        if (!is_pointer(expr))
                return;

        returned_name = expr_to_var_sym(expr, &returned_sym);
        if (!returned_name || !returned_sym)
                goto free;
        len = strlen(returned_name);

        FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
                if (!estate_rl(sm->state))
                        continue;
                if (returned_sym != sm->sym)
                        continue;
                if (strncmp(returned_name, sm->name, len) != 0)
                        continue;
                if (sm->name[len] != '-')
                        continue;

                snprintf(name_buf, sizeof(name_buf), "$%s", sm->name + len);

                compare_str = name_sym_to_param_comparison(sm->name, sm->sym);
                if (!compare_str && estate_is_whole(sm->state))
                        continue;
                snprintf(val_buf, sizeof(val_buf), "%s%s", sm->state->name, compare_str ?: "");

                sql_insert_return_states(return_id, return_ranges, PARAM_VALUE,
                                         -1, name_buf, val_buf);
        } END_FOR_EACH_SM(sm);

free:
        free_string(returned_name);
}

static void db_limited_before(void)
{
        unmatched_stree = clone_stree(__get_cur_stree());
}

static void db_limited_after(void)
{
        free_stree(&unmatched_stree);
}

static int basically_the_same(struct range_list *orig, struct range_list *new)
{
        if (rl_equiv(orig, new))
                return 1;

        /*
         * The whole range is essentially the same as 0,4096-27777777777 so
         * don't overwrite the implications just to store that.
         *
         */
        if (rl_type(orig)->type == SYM_PTR &&
            is_whole_rl(orig) &&
            rl_min(new).value == 0 &&
            rl_max(new).value == valid_ptr_max)
                return 1;
        return 0;
}

static void db_param_limit_binops(struct expression *arg, char *key, struct range_list *rl)
{
        struct range_list *left_rl;
        sval_t zero = { .type = rl_type(rl), };
        sval_t sval;

        if (arg->op != '*')
                return;
        if (!get_implied_value(arg->right, &sval))
                return;
        if (can_integer_overflow(get_type(arg), arg))
                return;

        left_rl = rl_binop(rl, '/', alloc_rl(sval, sval));
        if (!rl_has_sval(rl, zero))
                left_rl = remove_range(left_rl, zero, zero);

        set_extra_expr_nomod(arg->left, alloc_estate_rl(left_rl));
}

static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
{
        struct expression *arg;
        char *name;
        struct symbol *sym;
        struct var_sym_list *vsl = NULL;
        struct sm_state *sm;
        struct symbol *compare_type, *var_type;
        struct range_list *rl;
        struct range_list *limit;
        struct range_list *new;
        char *other_name;
        struct symbol *other_sym;

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

        arg = get_argument_from_call_expr(expr->args, param);
        if (!arg)
                return;

        if (strcmp(key, "$") == 0)
                compare_type = get_arg_type(expr->fn, param);
        else
                compare_type = get_member_type_from_key(arg, key);

        call_results_to_rl(expr, compare_type, value, &limit);
        if (strcmp(key, "$") == 0)
                move_known_to_rl(&arg, &limit);
        name = get_chunk_from_key(arg, key, &sym, &vsl);
        if (!name)
                return;
        if (op != PARAM_LIMIT && !sym)
                goto free;

        sm = get_sm_state(SMATCH_EXTRA, name, sym);
        if (sm)
                rl = estate_rl(sm->state);
        else
                rl = alloc_whole_rl(compare_type);

        if (op == PARAM_LIMIT && !rl_fits_in_type(rl, compare_type))
                goto free;

        new = rl_intersection(rl, limit);

        var_type = get_member_type_from_key(arg, key);
        new = cast_rl(var_type, new);

        /* We want to preserve the implications here */
        if (sm && basically_the_same(rl, new))
                goto free;
        other_name = get_other_name_sym(name, sym, &other_sym);

        if (op == PARAM_LIMIT)
                set_extra_nomod_vsl(name, sym, vsl, NULL, alloc_estate_rl(new));
        else
                set_extra_mod(name, sym, NULL, alloc_estate_rl(new));

        if (other_name && other_sym) {
                if (op == PARAM_LIMIT)
                        set_extra_nomod_vsl(other_name, other_sym, vsl, NULL, alloc_estate_rl(new));
                else
                        set_extra_mod(other_name, other_sym, NULL, alloc_estate_rl(new));
        }

        if (op == PARAM_LIMIT && arg->type == EXPR_BINOP)
                db_param_limit_binops(arg, key, new);
free:
        free_string(name);
}

static void db_param_limit(struct expression *expr, int param, char *key, char *value)
{
        db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
}

static void db_param_filter(struct expression *expr, int param, char *key, char *value)
{
        db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
}

static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
{
        struct expression *arg, *gen_expr;
        char *name;
        char *other_name = NULL;
        struct symbol *sym, *other_sym;
        struct symbol *param_type, *arg_type;
        struct smatch_state *state;
        struct range_list *new = NULL;
        struct range_list *added = NULL;

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

        arg = get_argument_from_call_expr(expr->args, param);
        if (!arg)
                return;

        arg_type = get_arg_type_from_key(expr->fn, param, arg, key);
        param_type = get_member_type_from_key(arg, key);
        if (param_type && param_type->type == SYM_STRUCT)
                return;
        name = get_variable_from_key(arg, key, &sym);
        if (!name || !sym)
                goto free;
        gen_expr = gen_expression_from_key(arg, key);

        state = get_state(SMATCH_EXTRA, name, sym);
        if (state)
                new = estate_rl(state);

        call_results_to_rl(expr, arg_type, value, &added);
        added = cast_rl(param_type, added);
        if (op == PARAM_SET)
                new = added;
        else
                new = rl_union(new, added);

        other_name = get_other_name_sym_nostack(name, sym, &other_sym);
        set_extra_mod(name, sym, gen_expr, alloc_estate_rl(new));
        if (other_name && other_sym)
                set_extra_mod(other_name, other_sym, gen_expr, alloc_estate_rl(new));
free:
        free_string(other_name);
        free_string(name);
}

static void db_param_add(struct expression *expr, int param, char *key, char *value)
{
        in_param_set = true;
        db_param_add_set(expr, param, key, value, PARAM_ADD);
        in_param_set = false;
}

static void db_param_set(struct expression *expr, int param, char *key, char *value)
{
        in_param_set = true;
        db_param_add_set(expr, param, key, value, PARAM_SET);
        in_param_set = false;
}

static void match_lost_param(struct expression *call, int param)
{
        struct expression *arg;

        if (is_const_param(call->fn, param))
                return;

        arg = get_argument_from_call_expr(call->args, param);
        if (!arg)
                return;

        arg = strip_expr(arg);
        if (arg->type == EXPR_PREOP && arg->op == '&')
                set_extra_expr_mod(arg->unop, alloc_estate_whole(get_type(arg->unop)));
        else
                ; /* if pointer then set struct members, maybe?*/
}

static void db_param_value(struct expression *expr, int param, char *key, char *value)
{
        struct expression *call;
        char *name;
        struct symbol *sym;
        struct symbol *type;
        struct range_list *rl = NULL;

        if (param != -1)
                return;

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

        type = get_member_type_from_key(expr->left, key);
        name = get_variable_from_key(expr->left, key, &sym);
        if (!name || !sym)
                goto free;

        call_results_to_rl(call, type, value, &rl);

        set_extra_mod(name, sym, NULL, alloc_estate_rl(rl));
free:
        free_string(name);
}

static void match_call_info(struct expression *expr)
{
        struct smatch_state *state;
        struct range_list *rl = NULL;
        struct expression *arg;
        struct symbol *type;
        sval_t dummy;
        int i = 0;

        FOR_EACH_PTR(expr->args, arg) {
                type = get_arg_type(expr->fn, i);

                get_absolute_rl(arg, &rl);
                rl = cast_rl(type, rl);

                if (!is_whole_rl(rl)) {
                        rl = intersect_with_real_abs_expr(arg, rl);
                        sql_insert_caller_info(expr, PARAM_VALUE, i, "$", show_rl(rl));
                }
                state = get_state_expr(SMATCH_EXTRA, arg);
                if (!estate_get_single_value(state, &dummy) && estate_has_hard_max(state)) {
                        sql_insert_caller_info(expr, HARD_MAX, i, "$",
                                               sval_to_str(estate_max(state)));
                }
                if (estate_has_fuzzy_max(state)) {
                        sql_insert_caller_info(expr, FUZZY_MAX, i, "$",
                                               sval_to_str(estate_get_fuzzy_max(state)));
                }
                i++;
        } END_FOR_EACH_PTR(arg);
}

static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
{
        struct expression *expr;
        struct range_list *rl = NULL;
        struct smatch_state *state;
        struct symbol *type;
        char *key_orig = key;
        char *fullname;
        sval_t dummy;

        expr = symbol_expression(sym);
        fullname = get_variable_from_key(expr, key, NULL);
        if (!fullname)
                return;

        type = get_member_type_from_key(expr, key_orig);
        str_to_rl(type, value, &rl);
        state = alloc_estate_rl(rl);
        if (estate_get_single_value(state, &dummy))
                estate_set_hard_max(state);
        set_state(SMATCH_EXTRA, fullname, sym, state);
}

static void set_param_fuzzy_max(const char *name, struct symbol *sym, char *key, char *value)
{
        struct expression *expr;
        struct range_list *rl = NULL;
        struct smatch_state *state;
        struct symbol *type;
        char *fullname;
        sval_t max;

        expr = symbol_expression(sym);
        fullname = get_variable_from_key(expr, key, NULL);
        if (!fullname)
                return;

        state = get_state(SMATCH_EXTRA, fullname, sym);
        if (!state)
                return;
        type = estate_type(state);
        str_to_rl(type, value, &rl);
        if (!rl_to_sval(rl, &max))
                return;
        estate_set_fuzzy_max(state, max);
}

static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
{
        struct smatch_state *state;
        struct expression *expr;
        char *fullname;

        expr = symbol_expression(sym);
        fullname = get_variable_from_key(expr, key, NULL);
        if (!fullname)
                return;

        state = get_state(SMATCH_EXTRA, fullname, sym);
        if (!state)
                return;
        estate_set_hard_max(state);
}

struct sm_state *get_extra_sm_state(struct expression *expr)
{
        char *name;
        struct symbol *sym;
        struct sm_state *ret = NULL;

        name = expr_to_known_chunk_sym(expr, &sym);
        if (!name)
                goto free;

        ret = get_sm_state(SMATCH_EXTRA, name, sym);
free:
        free_string(name);
        return ret;
}

struct smatch_state *get_extra_state(struct expression *expr)
{
        struct sm_state *sm;

        sm = get_extra_sm_state(expr);
        if (!sm)
                return NULL;
        return sm->state;
}

void register_smatch_extra(int id)
{
        my_id = id;

        set_dynamic_states(my_id);
        add_merge_hook(my_id, &merge_estates);
        add_unmatched_state_hook(my_id, &unmatched_state);
        select_caller_info_hook(set_param_value, PARAM_VALUE);
        select_caller_info_hook(set_param_fuzzy_max, FUZZY_MAX);
        select_caller_info_hook(set_param_hard_max, HARD_MAX);
        select_return_states_before(&db_limited_before);
        select_return_states_hook(PARAM_LIMIT, &db_param_limit);
        select_return_states_hook(PARAM_FILTER, &db_param_filter);
        select_return_states_hook(PARAM_ADD, &db_param_add);
        select_return_states_hook(PARAM_SET, &db_param_set);
        add_lost_param_hook(&match_lost_param);
        select_return_states_hook(PARAM_VALUE, &db_param_value);
        select_return_states_after(&db_limited_after);
}

static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
{
        struct var_sym_list *links;
        struct var_sym *tmp;
        struct smatch_state *state;

        links = sm->state->data;

        FOR_EACH_PTR(links, tmp) {
                if (sm->sym == tmp->sym &&
                    strcmp(sm->name, tmp->var) == 0)
                        continue;
                state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
                if (!state)
                        continue;
                set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
        } END_FOR_EACH_PTR(tmp);
        set_state(link_id, sm->name, sm->sym, &undefined);
}

void register_smatch_extra_links(int id)
{
        link_id = id;
        set_dynamic_states(link_id);
}

void register_smatch_extra_late(int id)
{
        add_merge_hook(link_id, &merge_link_states);
        add_modification_hook(link_id, &match_link_modify);
        add_hook(&match_dereferences, DEREF_HOOK);
        add_hook(&match_pointer_as_array, OP_HOOK);
        select_return_implies_hook(DEREFERENCE, &set_param_dereferenced);
        add_hook(&match_function_call, FUNCTION_CALL_HOOK);
        add_hook(&match_assign, ASSIGNMENT_HOOK);
        add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
        add_hook(&unop_expr, OP_HOOK);
        add_hook(&asm_expr, ASM_HOOK);

        add_hook(&match_call_info, FUNCTION_CALL_HOOK);
        add_member_info_callback(my_id, struct_member_callback);
        add_split_return_callback(&returned_struct_members);

//      add_hook(&assume_indexes_are_valid, OP_HOOK);
}