source: examples/gc_no_raii/src/internal/collector.c @ 17bc05b

#include "collector.h"

#ifdef __cforall
extern "C" {
#endif
#include <string.h>
#ifdef __cforall
}
#endif

#include <fstream.hfa>

#include "state.h"
#include "gcpointers.h"
#include "memory_pool.h"

void* gc_finish_alloc_block(void* block, size_t actual_size, size_t target_size);
void gc_assign_reference(void** ref, gc_object_header* ptr);

gcpointer_t** gc_find_previous_ref(gcpointer_t* target)
{
        if(!(target)) return NULL;

        bool managed = gc_is_managed(target);
        gc_object_header* obj = gc_get_object_ptr((void*)target->ptr);

        check(is_valid(obj));

        gcpointer_t** prev_next_ptr = managed ? &obj->type_chain : &obj->root_chain;
        while((*prev_next_ptr) && (*prev_next_ptr) != target)
        {
                prev_next_ptr = &(*prev_next_ptr)->next;
        }

        return prev_next_ptr;
}

void* gc_allocate(size_t target_size)
{
        // sout | "Allocating " | target_size | " bytes";

        size_t size = gc_compute_size(target_size + sizeof(gc_object_header));

        // sout | "Object header size: " | sizeof(gc_object_header) | " bytes";
        // sout | "Actual allocation size: " | size | " bytes";

        check(size < POOL_SIZE_BYTES);

        void* block = NULL;
        gc_state* gc = gc_get_state();

        if((intptr_t)(block = gc_try_allocate(gc, size))) return gc_finish_alloc_block(block, size, target_size);

        gc_collect(gc);

        if((intptr_t)(block = gc_try_allocate(gc, size))) return gc_finish_alloc_block(block, size, target_size);

        gc_allocate_pool(gc);

        if((intptr_t)(block = gc_try_allocate(gc, size))) return gc_finish_alloc_block(block, size, target_size);

        checkf( (int) 0, "ERROR: allocation in new pool failed");

        return NULL;
}

void* gc_finish_alloc_block(void* block, size_t actual_size, size_t target_size)
{
        intptr_t data = ((intptr_t)block) + sizeof(gc_object_header);
        void* header = block;

        check( data > ((intptr_t)block));
        check( data >= ((intptr_t)header));
        check( gc_is_aligned( (void*)data ) );
        check( data + target_size <= ((intptr_t)block) + actual_size );

        gc_object_header* obj = placement_ctor(header, actual_size);

        (void)obj; //remove unsused warning since this is for debug
        check(obj == gc_get_object_ptr( (void*)data ));

        gc_register_allocation(gc_get_state(), actual_size);

        return (void*)data;
}

void gc_process_reference(void** ref, worklist_t* worklist)
{
        check(!gc_is_in_heap(gc_get_state(), ref));

        gc_object_header* ptr = gc_get_object_ptr(*ref);
        if(ptr)
        {
                if(!ptr->is_forwarded)
                {
                        gc_copy_object(ptr);

                        gc_scan_object(ptr->forward, worklist);

                        gc_assign_reference(ref, ptr->forward);
                }
                else
                {
                        //duplication to help debug
                        gc_assign_reference(ref, ptr->forward);
                }
        }
}

void gc_assign_reference(void** ref, gc_object_header* ptr)
{
        void* address = (void*)(((intptr_t)ptr) + sizeof(gc_object_header));

        gc_write_aligned_ptr(ref, address);
}

gc_object_header* gc_copy_object(gc_object_header* ptr)
{
        check(!ptr->forward);
        check(!ptr->is_forwarded);
        check(gc_pool_is_from_space(gc_pool_of(ptr)));

        gc_memory_pool* pool = gc_pool_of(ptr)->mirror;

        void* new_block = gc_pool_allocate(pool, ptr->size, true);

        memcpy(new_block, ptr, ptr->size);

        gc_object_header* fwd_ptr = placement_copy_ctor(new_block, ptr);

        ptr->forward = fwd_ptr;
        ptr->is_forwarded = true;

        return fwd_ptr;
}

void gc_scan_object(gc_object_header* object, worklist_t* worklist)
{
        gcpointer_t* field = object->type_chain;
        while(field)
        {
                check(((intptr_t)field) > ((intptr_t)object));
                check(((intptr_t)field) < ((intptr_t)((intptr_t)object) + object->size));

                check(gc_is_in_to_space(gc_get_state(), &field->ptr));

                intptr_t* ref = &field->ptr;
                push_back(worklist, ref);

                field = field->next;
        }
}