namespace factor {
-/* The callback heap is used to store the machine code that alien-callbacks
-actually jump to when C code invokes them.
+// The callback heap is used to store the machine code that alien-callbacks
+// actually jump to when C code invokes them.
-The callback heap has entries that look like code_blocks from the code heap, but
-callback heap entries are allocated contiguously, never deallocated, and all
-fields but the owner are set to false_object. The owner points to the callback
-bottom word, whose entry point is the callback body itself, generated by the
-optimizing compiler. The machine code that follows a callback stub consists of a
-single CALLBACK_STUB machine code template, which performs a jump to a "far"
-address (on PowerPC and x86-64, its loaded into a register first).
+// The callback heap has entries that look like code_blocks from the code heap, but
+// callback heap entries are allocated contiguously, never deallocated, and all
+// fields but the owner are set to false_object. The owner points to the callback
+// bottom word, whose entry point is the callback body itself, generated by the
+// optimizing compiler. The machine code that follows a callback stub consists of a
+// single CALLBACK_STUB machine code template, which performs a jump to a "far"
+// address (on PowerPC and x86-64, its loaded into a register first).
-GC updates the CALLBACK_STUB code if the code block of the callback bottom word
-is ever moved. The callback stub itself won't move, though, and is never
-deallocated. This means that the callback stub itself is a stable function
-pointer that C code can hold on to until the associated Factor VM exits.
+// GC updates the CALLBACK_STUB code if the code block of the callback bottom word
+// is ever moved. The callback stub itself won't move, though, and is never
+// deallocated. This means that the callback stub itself is a stable function
+// pointer that C code can hold on to until the associated Factor VM exits.
-Since callback stubs are GC roots, and are never deallocated, the associated
-callback code in the code heap is also never deallocated.
+// Since callback stubs are GC roots, and are never deallocated, the associated
+// callback code in the code heap is also never deallocated.
-The callback heap is not saved in the image. Running GC in a new session after
-saving the image will deallocate any code heap entries that were only reachable
-from the callback heap in the previous session when the image was saved. */
+// The callback heap is not saved in the image. Running GC in a new session after
+// saving the image will deallocate any code heap entries that were only reachable
+// from the callback heap in the previous session when the image was saved.
struct callback_heap {
segment* seg;
- cell here;
+ free_list_allocator<code_block>* allocator;
factor_vm* parent;
callback_heap(cell size, factor_vm* parent);
~callback_heap();
- void* callback_entry_point(code_block* stub) {
- word* w = (word*)UNTAG(stub->owner);
- return w->entry_point;
- }
-
- bool setup_seh_p();
- bool return_takes_param_p();
instruction_operand callback_operand(code_block* stub, cell index);
- void store_callback_operand(code_block* stub, cell index);
void store_callback_operand(code_block* stub, cell index, cell value);
-
void update(code_block* stub);
-
code_block* add(cell owner, cell return_rewind);
-
- void update();
-
- code_block* next(code_block* stub) {
- return (code_block*)((cell) stub + stub->size());
- }
-
- template <typename Iterator> void each_callback(Iterator& iter) {
- code_block* scan = (code_block*)seg->start;
- code_block* end = (code_block*)here;
- while (scan < end) {
- iter(scan);
- scan = next(scan);
- }
- }
};
}