factor/vm/callbacks.cpp

111 lines
3.3 KiB
C++

#include "master.hpp"
namespace factor {
bool return_takes_param_p() {
#if defined(FACTOR_X86) || defined(FACTOR_AMD64)
return true;
#else
return false;
#endif
}
callback_heap::callback_heap(cell size, factor_vm* parent) {
seg = new segment(size, true);
if (!seg)
fatal_error("Out of memory in callback_heap constructor", size);
allocator = new free_list_allocator<code_block>(size, seg->start);
this->parent = parent;
}
callback_heap::~callback_heap() {
delete allocator;
allocator = NULL;
delete seg;
seg = NULL;
}
instruction_operand callback_heap::callback_operand(code_block* stub,
cell index) {
tagged<array> code_template(parent->special_objects[CALLBACK_STUB]);
tagged<byte_array> relocation_template(
array_nth(code_template.untagged(), 0));
relocation_entry entry(relocation_template->data<relocation_entry>()[index]);
return instruction_operand(entry, stub, 0);
}
void callback_heap::store_callback_operand(code_block* stub, cell index,
cell value) {
instruction_operand op = callback_operand(stub, index);
op.store_value(value);
}
void callback_heap::update(code_block* stub) {
word* w = untag<word>(stub->owner);
store_callback_operand(stub, 1, w->entry_point);
stub->flush_icache();
}
code_block* callback_heap::add(cell owner, cell return_rewind) {
// code_template is a 2-tuple where the first element contains the
// relocations and the second a byte array of compiled assembly
// code. The code assumes that there are four relocations on x86 and
// three on ppc.
tagged<array> code_template(parent->special_objects[CALLBACK_STUB]);
tagged<byte_array> insns(array_nth(code_template.untagged(), 1));
cell size = array_capacity(insns.untagged());
cell bump = align(size + sizeof(code_block), data_alignment);
code_block* stub = allocator->allot(bump);
if (!stub) {
parent->general_error(ERROR_CALLBACK_SPACE_OVERFLOW,
false_object,
false_object);
}
stub->header = bump & ~7;
stub->owner = owner;
stub->parameters = false_object;
stub->relocation = false_object;
memcpy((void*)stub->entry_point(), insns->data<void>(), size);
// Store VM pointer in two relocations.
store_callback_operand(stub, 0, (cell)parent);
store_callback_operand(stub, 2, (cell)parent);
// On x86, the RET instruction takes an argument which depends on
// the callback's calling convention
if (return_takes_param_p())
store_callback_operand(stub, 3, return_rewind);
update(stub);
return stub;
}
// Allocates memory (add(), allot_alien())
void factor_vm::primitive_callback() {
cell return_rewind = to_cell(ctx->pop());
tagged<word> w(ctx->pop());
check_tagged(w);
cell func = callbacks->add(w.value(), return_rewind)->entry_point();
CODE_TO_FUNCTION_POINTER_CALLBACK(this, func);
ctx->push(allot_alien(func));
}
void factor_vm::primitive_free_callback() {
void* entry_point = alien_offset(ctx->pop());
code_block* stub = (code_block*)entry_point - 1;
callbacks->allocator->free(stub);
}
// Allocates memory
void factor_vm::primitive_callback_room() {
allocator_room room = callbacks->allocator->as_allocator_room();
ctx->push(tag<byte_array>(byte_array_from_value(&room)));
}
}