cosmopolitan/third_party/quickjs/shape.c

/*
 * QuickJS Javascript Engine
 *
 * Copyright (c) 2017-2021 Fabrice Bellard
 * Copyright (c) 2017-2021 Charlie Gordon
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include "libc/assert.h"
#include "third_party/quickjs/internal.h"

asm(".ident\t\"\\n\\n\
QuickJS (MIT License)\\n\
Copyright (c) 2017-2021 Fabrice Bellard\\n\
Copyright (c) 2017-2021 Charlie Gordon\"");
asm(".include \"libc/disclaimer.inc\"");
/* clang-format off */

int init_shape_hash(JSRuntime *rt)
{
    rt->shape_hash_bits = 4;   /* 16 shapes */
    rt->shape_hash_size = 1 << rt->shape_hash_bits;
    rt->shape_hash_count = 0;
    rt->shape_hash = js_mallocz_rt(rt, sizeof(rt->shape_hash[0]) *
                                   rt->shape_hash_size);
    if (!rt->shape_hash)
        return -1;
    return 0;
}

/* same magic hash multiplier as the Linux kernel */
static uint32_t shape_hash(uint32_t h, uint32_t val)
{
    return (h + val) * 0x9e370001;
}

/* truncate the shape hash to 'hash_bits' bits */
static uint32_t get_shape_hash(uint32_t h, int hash_bits)
{
    return h >> (32 - hash_bits);
}

static uint32_t shape_initial_hash(JSObject *proto)
{
    uint32_t h;
    h = shape_hash(1, (uintptr_t)proto);
    if (sizeof(proto) > 4)
        h = shape_hash(h, (uint64_t)(uintptr_t)proto >> 32);
    return h;
}

static int resize_shape_hash(JSRuntime *rt, int new_shape_hash_bits)
{
    int new_shape_hash_size, i;
    uint32_t h;
    JSShape **new_shape_hash, *sh, *sh_next;
    new_shape_hash_size = 1 << new_shape_hash_bits;
    new_shape_hash = js_mallocz_rt(rt, sizeof(rt->shape_hash[0]) *
                                   new_shape_hash_size);
    if (!new_shape_hash)
        return -1;
    for(i = 0; i < rt->shape_hash_size; i++) {
        for(sh = rt->shape_hash[i]; sh != NULL; sh = sh_next) {
            sh_next = sh->shape_hash_next;
            h = get_shape_hash(sh->hash, new_shape_hash_bits);
            sh->shape_hash_next = new_shape_hash[h];
            new_shape_hash[h] = sh;
        }
    }
    js_free_rt(rt, rt->shape_hash);
    rt->shape_hash_bits = new_shape_hash_bits;
    rt->shape_hash_size = new_shape_hash_size;
    rt->shape_hash = new_shape_hash;
    return 0;
}

void js_shape_hash_link(JSRuntime *rt, JSShape *sh)
{
    uint32_t h;
    h = get_shape_hash(sh->hash, rt->shape_hash_bits);
    sh->shape_hash_next = rt->shape_hash[h];
    rt->shape_hash[h] = sh;
    rt->shape_hash_count++;
}

void js_shape_hash_unlink(JSRuntime *rt, JSShape *sh)
{
    uint32_t h;
    JSShape **psh;
    h = get_shape_hash(sh->hash, rt->shape_hash_bits);
    psh = &rt->shape_hash[h];
    while (*psh != sh)
        psh = &(*psh)->shape_hash_next;
    *psh = sh->shape_hash_next;
    rt->shape_hash_count--;
}

/* create a new empty shape with prototype 'proto' */
JSShape *js_new_shape2(JSContext *ctx, JSObject *proto, int hash_size, int prop_size)
{
    JSRuntime *rt = ctx->rt;
    void *sh_alloc;
    JSShape *sh;
    /* resize the shape hash table if necessary */
    if (2 * (rt->shape_hash_count + 1) > rt->shape_hash_size) {
        resize_shape_hash(rt, rt->shape_hash_bits + 1);
    }
    sh_alloc = js_malloc(ctx, get_shape_size(hash_size, prop_size));
    if (!sh_alloc)
        return NULL;
    sh = get_shape_from_alloc(sh_alloc, hash_size);
    sh->header.ref_count = 1;
    add_gc_object(rt, &sh->header, JS_GC_OBJ_TYPE_SHAPE);
    if (proto)
        JS_DupValue(ctx, JS_MKPTR(JS_TAG_OBJECT, proto));
    sh->proto = proto;
    bzero(prop_hash_end(sh) - hash_size, sizeof(prop_hash_end(sh)[0]) *
           hash_size);
    sh->prop_hash_mask = hash_size - 1;
    sh->prop_size = prop_size;
    sh->prop_count = 0;
    sh->deleted_prop_count = 0;
    /* insert in the hash table */
    sh->hash = shape_initial_hash(proto);
    sh->is_hashed = TRUE;
    sh->has_small_array_index = FALSE;
    js_shape_hash_link(ctx->rt, sh);
    return sh;
}

JSShape *js_new_shape(JSContext *ctx, JSObject *proto)
{
    return js_new_shape2(ctx, proto, JS_PROP_INITIAL_HASH_SIZE,
                         JS_PROP_INITIAL_SIZE);
}

/* The shape is cloned. The new shape is not inserted in the shape
   hash table */
JSShape *js_clone_shape(JSContext *ctx, JSShape *sh1)
{
    JSShape *sh;
    void *sh_alloc, *sh_alloc1;
    size_t size;
    JSShapeProperty *pr;
    uint32_t i, hash_size;
    hash_size = sh1->prop_hash_mask + 1;
    size = get_shape_size(hash_size, sh1->prop_size);
    sh_alloc = js_malloc(ctx, size);
    if (!sh_alloc)
        return NULL;
    sh_alloc1 = get_alloc_from_shape(sh1);
    memcpy(sh_alloc, sh_alloc1, size);
    sh = get_shape_from_alloc(sh_alloc, hash_size);
    sh->header.ref_count = 1;
    add_gc_object(ctx->rt, &sh->header, JS_GC_OBJ_TYPE_SHAPE);
    sh->is_hashed = FALSE;
    if (sh->proto) {
        JS_DupValue(ctx, JS_MKPTR(JS_TAG_OBJECT, sh->proto));
    }
    for(i = 0, pr = get_shape_prop(sh); i < sh->prop_count; i++, pr++) {
        JS_DupAtom(ctx, pr->atom);
    }
    return sh;
}

JSShape *js_dup_shape(JSShape *sh)
{
    sh->header.ref_count++;
    return sh;
}

static void js_free_shape0(JSRuntime *rt, JSShape *sh)
{
    uint32_t i;
    JSShapeProperty *pr;
    assert(sh->header.ref_count == 0);
    if (sh->is_hashed)
        js_shape_hash_unlink(rt, sh);
    if (sh->proto != NULL) {
        JS_FreeValueRT(rt, JS_MKPTR(JS_TAG_OBJECT, sh->proto));
    }
    pr = get_shape_prop(sh);
    for(i = 0; i < sh->prop_count; i++) {
        JS_FreeAtomRT(rt, pr->atom);
        pr++;
    }
    remove_gc_object(&sh->header);
    js_free_rt(rt, get_alloc_from_shape(sh));
}

void js_free_shape(JSRuntime *rt, JSShape *sh)
{
    if (UNLIKELY(--sh->header.ref_count <= 0)) {
        js_free_shape0(rt, sh);
    }
}

int add_shape_property(JSContext *ctx, JSShape **psh,
                       JSObject *p, JSAtom atom, int prop_flags)
{
    JSRuntime *rt = ctx->rt;
    JSShape *sh = *psh;
    JSShapeProperty *pr, *prop;
    uint32_t hash_mask, new_shape_hash = 0;
    intptr_t h;
    /* update the shape hash */
    if (sh->is_hashed) {
        js_shape_hash_unlink(rt, sh);
        new_shape_hash = shape_hash(shape_hash(sh->hash, atom), prop_flags);
    }
    if (UNLIKELY(sh->prop_count >= sh->prop_size)) {
        if (resize_properties(ctx, psh, p, sh->prop_count + 1)) {
            /* in case of error, reinsert in the hash table.
               sh is still valid if resize_properties() failed */
            if (sh->is_hashed)
                js_shape_hash_link(rt, sh);
            return -1;
        }
        sh = *psh;
    }
    if (sh->is_hashed) {
        sh->hash = new_shape_hash;
        js_shape_hash_link(rt, sh);
    }
    /* Initialize the new shape property.
       The object property at p->prop[sh->prop_count] is uninitialized */
    prop = get_shape_prop(sh);
    pr = &prop[sh->prop_count++];
    pr->atom = JS_DupAtom(ctx, atom);
    pr->flags = prop_flags;
    sh->has_small_array_index |= __JS_AtomIsTaggedInt(atom);
    /* add in hash table */
    hash_mask = sh->prop_hash_mask;
    h = atom & hash_mask;
    pr->hash_next = prop_hash_end(sh)[-h - 1];
    prop_hash_end(sh)[-h - 1] = sh->prop_count;
    return 0;
}

/* find a hashed empty shape matching the prototype. Return NULL if
   not found */
JSShape *find_hashed_shape_proto(JSRuntime *rt, JSObject *proto)
{
    JSShape *sh1;
    uint32_t h, h1;
    h = shape_initial_hash(proto);
    h1 = get_shape_hash(h, rt->shape_hash_bits);
    for(sh1 = rt->shape_hash[h1]; sh1 != NULL; sh1 = sh1->shape_hash_next) {
        if (sh1->hash == h &&
            sh1->proto == proto &&
            sh1->prop_count == 0) {
            return sh1;
        }
    }
    return NULL;
}

/* find a hashed shape matching sh + (prop, prop_flags). Return NULL if
   not found */
JSShape *find_hashed_shape_prop(JSRuntime *rt, JSShape *sh, JSAtom atom, int prop_flags)
{
    JSShape *sh1;
    uint32_t h, h1, i, n;
    h = sh->hash;
    h = shape_hash(h, atom);
    h = shape_hash(h, prop_flags);
    h1 = get_shape_hash(h, rt->shape_hash_bits);
    for(sh1 = rt->shape_hash[h1]; sh1 != NULL; sh1 = sh1->shape_hash_next) {
        /* we test the hash first so that the rest is done only if the
           shapes really match */
        if (sh1->hash == h &&
            sh1->proto == sh->proto &&
            sh1->prop_count == ((n = sh->prop_count) + 1)) {
            for(i = 0; i < n; i++) {
                if (UNLIKELY(sh1->prop[i].atom != sh->prop[i].atom) ||
                    UNLIKELY(sh1->prop[i].flags != sh->prop[i].flags))
                    goto next;
            }
            if (UNLIKELY(sh1->prop[n].atom != atom) ||
                UNLIKELY(sh1->prop[n].flags != prop_flags))
                goto next;
            return sh1;
        }
    next: ;
    }
    return NULL;
}

static __maybe_unused void JS_DumpShape(JSRuntime *rt, int i, JSShape *sh)
{
    char atom_buf[ATOM_GET_STR_BUF_SIZE];
    int j;
    /* XXX: should output readable class prototype */
    printf("%5d %3d%c %14p %5d %5d", i,
           sh->header.ref_count, " *"[sh->is_hashed],
           (void *)sh->proto, sh->prop_size, sh->prop_count);
    for(j = 0; j < sh->prop_count; j++) {
        printf(" %s", JS_AtomGetStrRT(rt, atom_buf, sizeof(atom_buf),
                                      sh->prop[j].atom));
    }
    printf("\n");
}

static __maybe_unused void JS_DumpShapes(JSRuntime *rt)
{
    int i;
    JSShape *sh;
    struct list_head *el;
    JSObject *p;
    JSGCObjectHeader *gp;
    printf("JSShapes: {\n");
    printf("%5s %4s %14s %5s %5s %s\n", "SLOT", "REFS", "PROTO", "SIZE", "COUNT", "PROPS");
    for(i = 0; i < rt->shape_hash_size; i++) {
        for(sh = rt->shape_hash[i]; sh != NULL; sh = sh->shape_hash_next) {
            JS_DumpShape(rt, i, sh);
            assert(sh->is_hashed);
        }
    }
    /* dump non-hashed shapes */
    list_for_each(el, &rt->gc_obj_list) {
        gp = list_entry(el, JSGCObjectHeader, link);
        if (gp->gc_obj_type == JS_GC_OBJ_TYPE_JS_OBJECT) {
            p = (JSObject *)gp;
            if (!p->shape->is_hashed) {
                JS_DumpShape(rt, -1, p->shape);
            }
        }
    }
    printf("}\n");
}

JSValue JS_NewObjectFromShape(JSContext *ctx, JSShape *sh, JSClassID class_id)
{
    JSObject *p;
    js_trigger_gc(ctx->rt, sizeof(JSObject));
    p = js_malloc(ctx, sizeof(JSObject));
    if (UNLIKELY(!p))
        goto fail;
    p->class_id = class_id;
    p->extensible = TRUE;
    p->free_mark = 0;
    p->is_exotic = 0;
    p->fast_array = 0;
    p->is_constructor = 0;
    p->is_uncatchable_error = 0;
    p->tmp_mark = 0;
    p->is_HTMLDDA = 0;
    p->first_weak_ref = NULL;
    p->u.opaque = NULL;
    p->shape = sh;
    p->prop = js_malloc(ctx, sizeof(JSProperty) * sh->prop_size);
    if (UNLIKELY(!p->prop)) {
        js_free(ctx, p);
    fail:
        js_free_shape(ctx->rt, sh);
        return JS_EXCEPTION;
    }
    switch(class_id) {
    case JS_CLASS_OBJECT:
        break;
    case JS_CLASS_ARRAY:
        {
            JSProperty *pr;
            p->is_exotic = 1;
            p->fast_array = 1;
            p->u.array.u.values = NULL;
            p->u.array.count = 0;
            p->u.array.u1.size = 0;
            /* the length property is always the first one */
            if (LIKELY(sh == ctx->array_shape)) {
                pr = &p->prop[0];
            } else {
                /* only used for the first array */
                /* cannot fail */
                pr = add_property(ctx, p, JS_ATOM_length,
                                  JS_PROP_WRITABLE | JS_PROP_LENGTH);
            }
            pr->u.value = JS_NewInt32(ctx, 0);
        }
        break;
    case JS_CLASS_C_FUNCTION:
        p->prop[0].u.value = JS_UNDEFINED;
        break;
    case JS_CLASS_ARGUMENTS:
    case JS_CLASS_UINT8C_ARRAY:
    case JS_CLASS_INT8_ARRAY:
    case JS_CLASS_UINT8_ARRAY:
    case JS_CLASS_INT16_ARRAY:
    case JS_CLASS_UINT16_ARRAY:
    case JS_CLASS_INT32_ARRAY:
    case JS_CLASS_UINT32_ARRAY:
#ifdef CONFIG_BIGNUM
    case JS_CLASS_BIG_INT64_ARRAY:
    case JS_CLASS_BIG_UINT64_ARRAY:
#endif
    case JS_CLASS_FLOAT32_ARRAY:
    case JS_CLASS_FLOAT64_ARRAY:
        p->is_exotic = 1;
        p->fast_array = 1;
        p->u.array.u.ptr = NULL;
        p->u.array.count = 0;
        break;
    case JS_CLASS_DATAVIEW:
        p->u.array.u.ptr = NULL;
        p->u.array.count = 0;
        break;
    case JS_CLASS_NUMBER:
    case JS_CLASS_STRING:
    case JS_CLASS_BOOLEAN:
    case JS_CLASS_SYMBOL:
    case JS_CLASS_DATE:
#ifdef CONFIG_BIGNUM
    case JS_CLASS_BIG_INT:
    case JS_CLASS_BIG_FLOAT:
    case JS_CLASS_BIG_DECIMAL:
#endif
        p->u.object_data = JS_UNDEFINED;
        goto set_exotic;
    case JS_CLASS_REGEXP:
        p->u.regexp.pattern = NULL;
        p->u.regexp.bytecode = NULL;
        goto set_exotic;
    default:
    set_exotic:
        if (ctx->rt->class_array[class_id].exotic) {
            p->is_exotic = 1;
        }
        break;
    }
    p->header.ref_count = 1;
    add_gc_object(ctx->rt, &p->header, JS_GC_OBJ_TYPE_JS_OBJECT);
    return JS_MKPTR(JS_TAG_OBJECT, p);
}