/*      $NetBSD: mem1.c,v 1.77 2023/12/03 18:17:41 rillig Exp $ */

/*
 * Copyright (c) 1994, 1995 Jochen Pohl
 * All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Jochen Pohl for
 *      The NetBSD Project.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
#if defined(__RCSID)
__RCSID("$NetBSD: mem1.c,v 1.77 2023/12/03 18:17:41 rillig Exp $");
#endif

#include <sys/param.h>
#include <stdlib.h>
#include <string.h>

#include "lint1.h"

/*
 * Filenames allocated by record_filename are shared and have unlimited
 * lifetime.
 */
struct filename {
        const char *fn_name;
        size_t  fn_len;
        int     fn_id;
        struct filename *fn_next;
};

static struct filename *filenames;      /* null-terminated array */
static int next_filename_id;

/* Find the given filename, or return NULL. */
static const struct filename *
search_filename(const char *s, size_t len)
{
        const struct filename *fn;

        for (fn = filenames; fn != NULL; fn = fn->fn_next) {
                if (fn->fn_len == len && memcmp(fn->fn_name, s, len) == 0)
                        break;
        }
        return fn;
}

struct filename_replacement {
        const char *orig;
        size_t orig_len;
        const char *repl;
        const struct filename_replacement *next;
};

static struct filename_replacement *filename_replacements;

void
add_directory_replacement(char *arg)
{
        struct filename_replacement *r = xmalloc(sizeof(*r));

        char *sep = strchr(arg, '=');
        if (sep == NULL)
                err(1, "Bad replacement directory spec `%s'", arg);
        *sep = '\0';

        r->orig = arg;
        r->orig_len = (size_t)(sep - arg);
        r->repl = sep + 1;
        r->next = filename_replacements;
        filename_replacements = r;
}

const char *
transform_filename(const char *name, size_t len)
{
        static char buf[MAXPATHLEN];
        const struct filename_replacement *r;

        for (r = filename_replacements; r != NULL; r = r->next)
                if (r->orig_len < len &&
                    memcmp(name, r->orig, r->orig_len) == 0)
                        break;
        if (r == NULL)
                return name;
        (void)snprintf(buf, sizeof(buf), "%s%s", r->repl, name + r->orig_len);
        return buf;
}

/*
 * Return a copy of the filename s with unlimited lifetime.
 * If the filename is new, write it to the output file.
 */
const char *
record_filename(const char *s, size_t slen)
{

        const struct filename *existing_fn = search_filename(s, slen);
        if (existing_fn != NULL)
                return existing_fn->fn_name;

        char *name = xmalloc(slen + 1);
        (void)memcpy(name, s, slen);
        name[slen] = '\0';

        struct filename *fn = xmalloc(sizeof(*fn));
        fn->fn_name = name;
        fn->fn_len = slen;
        fn->fn_id = next_filename_id++;
        fn->fn_next = filenames;
        filenames = fn;

        outint(fn->fn_id);
        outchar('s');
        outstrg(transform_filename(fn->fn_name, fn->fn_len));
        outchar('\n');

        return fn->fn_name;
}

/* Get the ID of a filename. */
int
get_filename_id(const char *s)
{
        const struct filename *fn;

        if (s == NULL || (fn = search_filename(s, strlen(s))) == NULL)
                return -1;
        return fn->fn_id;
}

typedef struct memory_pools {
        struct memory_pool *pools;
        size_t  cap;
} memory_pools;

/* Array of memory pools, indexed by mem_block_level. */
static memory_pools mpools;

/* The pool for the current expression is independent of any block level. */
static memory_pool expr_pool;

static void
mpool_add(memory_pool *pool, struct memory_pool_item item)
{

        if (pool->len >= pool->cap) {
                pool->cap = 2 * pool->len + 16;
                pool->items = xrealloc(pool->items,
                    sizeof(*pool->items) * pool->cap);
        }
        pool->items[pool->len++] = item;
}

#ifdef DEBUG_MEM
static void
debug_memory_pool_item(const struct memory_pool_item *item)
{
        void *p = item->p;
        size_t size = item->size;
        const char *descr = item->descr;

        if (strcmp(descr, "string") == 0) {
                const char *str = p;
                debug_step("%s: freeing string '%s'", __func__, str);
        } else if (strcmp(descr, "sym") == 0) {
                const sym_t *sym = p;
                debug_step("%s: freeing symbol '%s'", __func__, sym->s_name);
        } else if (strcmp(descr, "type") == 0) {
                const type_t *tp = p;
                debug_step("%s: freeing type '%s'", __func__, type_name(tp));
        } else if (strcmp(descr, "tnode") == 0) {
                const tnode_t *tn = p;
                debug_step("%s: freeing node '%s' with type '%s'",
                    __func__, op_name(tn->tn_op), type_name(tn->tn_type));
        } else
                debug_step("%s: freeing '%s' with %zu bytes",
                    __func__, descr, size);
}
#endif

static void
mpool_free(memory_pool *pool)
{

#ifdef DEBUG_MEM
        for (size_t i = pool->len; i-- > 0; )
                debug_memory_pool_item(pool->items + i);
#endif

        for (size_t i = pool->len; i-- > 0;) {
#ifdef DEBUG_MEM
                static void *(*volatile set)(void *, int, size_t) = memset;
                set(pool->items[i].p, 'Z', pool->items[i].size);
#endif
                free(pool->items[i].p);
        }
        pool->len = 0;
}

static void *
#ifdef DEBUG_MEM
mpool_zero_alloc(memory_pool *pool, size_t size, const char *descr)
#else
mpool_zero_alloc(memory_pool *pool, size_t size)
#endif
{

        void *mem = xmalloc(size);
        memset(mem, 0, size);
#if DEBUG_MEM
        mpool_add(pool, (struct memory_pool_item){ mem, size, descr });
#else
        mpool_add(pool, (struct memory_pool_item){ mem });
#endif
        return mem;
}

static memory_pool *
mpool_at(size_t level)
{

        if (level >= mpools.cap) {
                size_t prev_cap = mpools.cap;
                mpools.cap = level + 16;
                mpools.pools = xrealloc(mpools.pools,
                    sizeof(*mpools.pools) * mpools.cap);
                for (size_t i = prev_cap; i < mpools.cap; i++)
                        mpools.pools[i] = (memory_pool){ NULL, 0, 0 };
        }
        return mpools.pools + level;
}


/* Allocate memory associated with the level, initialized with zero. */
#ifdef DEBUG_MEM
void *
level_zero_alloc(size_t level, size_t size, const char *descr)
{

        debug_step("%s: %s at level %zu", __func__, descr, level);
        return mpool_zero_alloc(mpool_at(level), size, descr);
}
#else
void *
(level_zero_alloc)(size_t level, size_t size)
{

        return mpool_zero_alloc(mpool_at(level), size);
}
#endif

/* Allocate memory that is freed at the end of the current block. */
#ifdef DEBUG_MEM
void *
block_zero_alloc(size_t size, const char *descr)
{

        return level_zero_alloc(mem_block_level, size, descr);
}
#else
void *
(block_zero_alloc)(size_t size)
{

        return (level_zero_alloc)(mem_block_level, size);
}
#endif

void
level_free_all(size_t level)
{

        debug_step("+ %s %zu", __func__, level);
        debug_indent_inc();
        mpool_free(mpool_at(level));
        debug_leave();
}

/* Allocate memory that is freed at the end of the current expression. */
#if DEBUG_MEM
void *
expr_zero_alloc(size_t s, const char *descr)
{

        return mpool_zero_alloc(&expr_pool, s, descr);
}
#else
void *
(expr_zero_alloc)(size_t size)
{

        return mpool_zero_alloc(&expr_pool, size);
}
#endif

static bool
str_ends_with(const char *haystack, const char *needle)
{
        size_t hlen = strlen(haystack);
        size_t nlen = strlen(needle);

        return nlen <= hlen &&
            memcmp(haystack + hlen - nlen, needle, nlen) == 0;
}

/*
 * Return a freshly allocated tree node that is freed at the end of the
 * current expression.
 *
 * The node records whether it comes from a system file, which makes strict
 * bool mode less restrictive.
 */
tnode_t *
expr_alloc_tnode(void)
{
        tnode_t *tn = expr_zero_alloc(sizeof(*tn), "tnode");
        /*
         * files named *.c that are different from the main translation unit
         * typically contain generated code that cannot be influenced, such as
         * a flex lexer or a yacc parser.
         */
        tn->tn_sys = in_system_header ||
                     (curr_pos.p_file != csrc_pos.p_file &&
                      str_ends_with(curr_pos.p_file, ".c"));
        return tn;
}

/* Free all memory which is allocated by the current expression. */
void
expr_free_all(void)
{

        debug_step("%s", __func__);
        mpool_free(&expr_pool);
}

/*
 * Save the memory which is used by the current expression. This memory
 * is not freed by the next expr_free_all() call. The returned value can be
 * used to restore the memory.
 */
memory_pool
expr_save_memory(void)
{

        memory_pool saved_pool = expr_pool;
        expr_pool = (memory_pool){ NULL, 0, 0 };
        return saved_pool;
}

/*
 * Free all memory used for the current expression and restore the memory used
 * by a previous expression and saved by expr_save_memory(). The next call to
 * expr_free_all() frees the restored memory.
 */
void
expr_restore_memory(memory_pool saved_pool)
{

        expr_free_all();
        free(expr_pool.items);
        expr_pool = saved_pool;
}