mirror of
https://github.com/janet-lang/janet
synced 2024-11-15 13:14:48 +00:00
363 lines
11 KiB
C
363 lines
11 KiB
C
/*
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* Copyright (c) 2017 Calvin Rose
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include <dst/dst.h>
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#include "symcache.h"
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#include "gc.h"
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/* GC State */
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void *dst_vm_blocks;
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uint32_t dst_vm_gc_interval;
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uint32_t dst_vm_next_collection;
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/* Roots */
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DstValue *dst_vm_roots;
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uint32_t dst_vm_root_count;
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uint32_t dst_vm_root_capacity;
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/* Helpers for marking the various gc types */
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static void dst_mark_funcenv(DstFuncEnv *env);
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static void dst_mark_funcdef(DstFuncDef *def);
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static void dst_mark_function(DstFunction *func);
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static void dst_mark_array(DstArray *array);
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static void dst_mark_table(DstTable *table);
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static void dst_mark_struct(const DstValue *st);
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static void dst_mark_tuple(const DstValue *tuple);
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static void dst_mark_buffer(DstBuffer *buffer);
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static void dst_mark_string(const uint8_t *str);
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static void dst_mark_fiber(DstFiber *fiber);
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static void dst_mark_udata(void *udata);
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/* Mark a value */
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void dst_mark(DstValue x) {
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switch (dst_type(x)) {
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default: break;
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case DST_STRING:
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case DST_SYMBOL: dst_mark_string(dst_unwrap_string(x)); break;
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case DST_FUNCTION: dst_mark_function(dst_unwrap_function(x)); break;
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case DST_ARRAY: dst_mark_array(dst_unwrap_array(x)); break;
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case DST_TABLE: dst_mark_table(dst_unwrap_table(x)); break;
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case DST_STRUCT: dst_mark_struct(dst_unwrap_struct(x)); break;
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case DST_TUPLE: dst_mark_tuple(dst_unwrap_tuple(x)); break;
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case DST_BUFFER: dst_mark_buffer(dst_unwrap_buffer(x)); break;
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case DST_FIBER: dst_mark_fiber(dst_unwrap_fiber(x)); break;
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case DST_USERDATA: dst_mark_udata(dst_unwrap_pointer(x)); break;
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}
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}
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static void dst_mark_string(const uint8_t *str) {
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dst_gc_mark(dst_string_raw(str));
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}
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static void dst_mark_buffer(DstBuffer *buffer) {
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dst_gc_mark(buffer);
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}
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static void dst_mark_udata(void *udata) {
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dst_gc_mark(dst_userdata_header(udata));
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}
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/* Mark a bunch of items in memory */
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static void dst_mark_many(const DstValue *values, int32_t n) {
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const DstValue *end = values + n;
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while (values < end) {
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dst_mark(*values);
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values += 1;
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}
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}
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static void dst_mark_array(DstArray *array) {
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if (dst_gc_reachable(array))
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return;
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dst_gc_mark(array);
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dst_mark_many(array->data, array->count);
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}
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static void dst_mark_table(DstTable *table) {
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if (dst_gc_reachable(table))
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return;
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dst_gc_mark(table);
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dst_mark_many(table->data, table->capacity);
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}
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static void dst_mark_struct(const DstValue *st) {
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if (dst_gc_reachable(dst_struct_raw(st)))
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return;
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dst_gc_mark(dst_struct_raw(st));
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dst_mark_many(st, dst_struct_capacity(st));
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}
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static void dst_mark_tuple(const DstValue *tuple) {
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if (dst_gc_reachable(dst_tuple_raw(tuple)))
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return;
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dst_gc_mark(dst_tuple_raw(tuple));
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dst_mark_many(tuple, dst_tuple_length(tuple));
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}
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/* Helper to mark function environments */
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static void dst_mark_funcenv(DstFuncEnv *env) {
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if (dst_gc_reachable(env))
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return;
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dst_gc_mark(env);
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if (env->offset) {
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/* On stack */
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dst_mark_fiber(env->as.fiber);
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} else {
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/* Not on stack */
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dst_mark_many(env->as.values, env->length);
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}
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}
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/* GC helper to mark a FuncDef */
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static void dst_mark_funcdef(DstFuncDef *def) {
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int32_t count, i;
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if (dst_gc_reachable(def))
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return;
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dst_gc_mark(def);
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if (def->constants) {
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count = def->constants_length;
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for (i = 0; i < count; ++i) {
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DstValue v = def->constants[i];
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/* Funcdefs use nil literals to store other funcdefs */
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if (dst_checktype(v, DST_NIL)) {
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dst_mark_funcdef((DstFuncDef *) dst_unwrap_pointer(v));
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} else {
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dst_mark(v);
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}
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}
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}
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if (def->source)
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dst_mark_string(def->source);
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if (def->sourcepath)
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dst_mark_string(def->sourcepath);
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}
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static void dst_mark_function(DstFunction *func) {
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int32_t i;
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int32_t numenvs;
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if (dst_gc_reachable(func))
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return;
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dst_gc_mark(func);
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numenvs = func->def->environments_length;
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if (NULL != func->envs)
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for (i = 0; i < numenvs; ++i)
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if (NULL != func->envs[i])
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dst_mark_funcenv(func->envs[i]);
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dst_mark_funcdef(func->def);
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}
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static void dst_mark_fiber(DstFiber *fiber) {
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int32_t i, j;
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DstStackFrame *frame;
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if (dst_gc_reachable(fiber))
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return;
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dst_gc_mark(fiber);
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i = fiber->frame;
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j = fiber->frametop;
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while (i > 0) {
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frame = (DstStackFrame *)(fiber->data + i - DST_FRAME_SIZE);
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if (NULL != frame->func)
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dst_mark_function(frame->func);
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/* Mark all values in the stack frame */
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dst_mark_many(fiber->data + i, j - i);
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j = i - DST_FRAME_SIZE;
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i = frame->prevframe;
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}
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if (NULL != fiber->parent)
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dst_mark_fiber(fiber->parent);
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dst_mark(fiber->ret);
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}
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/* Deinitialize a block of memory */
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static void dst_deinit_block(DstGCMemoryHeader *block) {
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void *mem = ((char *)(block + 1));
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DstUserdataHeader *h = (DstUserdataHeader *)mem;
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switch (block->flags & DST_MEM_TYPEBITS) {
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default:
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break; /* Do nothing for non gc types */
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case DST_MEMORY_SYMBOL:
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dst_symbol_deinit((const uint8_t *)mem + 2 * sizeof(int32_t));
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break;
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case DST_MEMORY_ARRAY:
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dst_array_deinit((DstArray*) mem);
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break;
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case DST_MEMORY_TABLE:
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dst_table_deinit((DstTable*) mem);
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break;
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case DST_MEMORY_FIBER:
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free(((DstFiber *) mem)->data);
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break;
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case DST_MEMORY_BUFFER:
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dst_buffer_deinit((DstBuffer *) mem);
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break;
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case DST_MEMORY_FUNCTION:
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free(((DstFunction *)mem)->envs);
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break;
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case DST_MEMORY_USERDATA:
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if (h->type->finalize)
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h->type->finalize((void *)(h + 1), h->size);
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break;
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case DST_MEMORY_FUNCENV:
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{
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DstFuncEnv *env = (DstFuncEnv *)mem;
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if (0 == env->offset)
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free(env->as.values);
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}
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break;
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case DST_MEMORY_FUNCDEF:
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{
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DstFuncDef *def = (DstFuncDef *)mem;
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/* TODO - get this all with one alloc and one free */
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free(def->environments);
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free(def->constants);
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free(def->bytecode);
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free(def->sourcemap);
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}
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break;
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}
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}
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/* Iterate over all allocated memory, and free memory that is not
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* marked as reachable. Flip the gc color flag for next sweep. */
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void dst_sweep() {
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DstGCMemoryHeader *previous = NULL;
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DstGCMemoryHeader *current = dst_vm_blocks;
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DstGCMemoryHeader *next;
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while (NULL != current) {
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next = current->next;
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if (current->flags & (DST_MEM_REACHABLE | DST_MEM_DISABLED)) {
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previous = current;
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current->flags &= ~DST_MEM_REACHABLE;
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} else {
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dst_deinit_block(current);
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if (NULL != previous) {
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previous->next = next;
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} else {
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dst_vm_blocks = next;
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}
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free(current);
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}
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current = next;
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}
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}
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/* Allocate some memory that is tracked for garbage collection */
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void *dst_gcalloc(DstMemoryType type, size_t size) {
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DstGCMemoryHeader *mdata;
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size_t total = size + sizeof(DstGCMemoryHeader);
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/* Make sure everything is inited */
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dst_assert(NULL != dst_vm_cache, "please initialize dst before use");
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void *mem = malloc(total);
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/* Check for bad malloc */
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if (NULL == mem) {
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DST_OUT_OF_MEMORY;
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}
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mdata = (DstGCMemoryHeader *)mem;
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/* Configure block */
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mdata->flags = type;
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/* Prepend block to heap list */
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dst_vm_next_collection += size;
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mdata->next = dst_vm_blocks;
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dst_vm_blocks = mdata;
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return mem + sizeof(DstGCMemoryHeader);
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}
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/* Run garbage collection */
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void dst_collect() {
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uint32_t i;
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if (dst_vm_fiber)
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dst_mark_fiber(dst_vm_fiber);
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for (i = 0; i < dst_vm_root_count; i++)
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dst_mark(dst_vm_roots[i]);
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dst_sweep();
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dst_vm_next_collection = 0;
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}
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/* Add a root value to the GC. This prevents the GC from removing a value
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* and all of its children. If gcroot is called on a value n times, unroot
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* must also be called n times to remove it as a gc root. */
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void dst_gcroot(DstValue root) {
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uint32_t newcount = dst_vm_root_count + 1;
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if (newcount > dst_vm_root_capacity) {
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uint32_t newcap = 2 * newcount;
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dst_vm_roots = realloc(dst_vm_roots, sizeof(DstValue) * newcap);
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if (NULL == dst_vm_roots) {
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DST_OUT_OF_MEMORY;
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}
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dst_vm_root_capacity = newcap;
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}
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dst_vm_roots[dst_vm_root_count] = root;
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dst_vm_root_count = newcount;
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}
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/* Remove a root value from the GC. This allows the gc to potentially reclaim
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* a value and all its children. */
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int dst_gcunroot(DstValue root) {
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DstValue *vtop = dst_vm_roots + dst_vm_root_count;
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DstValue *v = dst_vm_roots;
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/* Search from top to bottom as access is most likely LIFO */
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for (v = dst_vm_roots; v < vtop; v++) {
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if (dst_equals(root, *v)) {
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*v = dst_vm_roots[--dst_vm_root_count];
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return 1;
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}
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}
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return 0;
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}
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/* Remove a root value from the GC. This sets the effective reference count to 0. */
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int dst_gcunrootall(DstValue root) {
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DstValue *vtop = dst_vm_roots + dst_vm_root_count;
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DstValue *v = dst_vm_roots;
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int ret = 0;
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/* Search from top to bottom as access is most likely LIFO */
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for (v = dst_vm_roots; v < vtop; v++) {
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if (dst_equals(root, *v)) {
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*v = dst_vm_roots[--dst_vm_root_count];
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vtop--;
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ret = 1;
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}
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}
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return ret;
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}
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/* Free all allocated memory */
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void dst_clear_memory() {
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DstGCMemoryHeader *current = dst_vm_blocks;
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while (current) {
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dst_deinit_block(current);
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DstGCMemoryHeader *next = current->next;
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free(current);
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current = next;
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}
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dst_vm_blocks = NULL;
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}
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