152 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C++
		
	
	
			
		
		
	
	
			152 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C++
		
	
	
#include "master.hpp"
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namespace factor {
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callback_heap::callback_heap(cell size, factor_vm* parent) {
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  seg = new segment(size, true);
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  if (!seg)
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    fatal_error("Out of memory in callback_heap constructor", size);
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  allocator = new free_list_allocator<code_block>(size, seg->start);
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  this->parent = parent;
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}
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callback_heap::~callback_heap() {
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  delete allocator;
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  allocator = NULL;
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  delete seg;
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  seg = NULL;
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}
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void factor_vm::init_callbacks(cell size) {
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  callbacks = new callback_heap(size, this);
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}
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bool callback_heap::setup_seh_p() {
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#if defined(WINDOWS) && defined(FACTOR_X86)
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  return true;
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#else
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  return false;
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#endif
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}
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bool callback_heap::return_takes_param_p() {
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#if defined(FACTOR_X86) || defined(FACTOR_AMD64)
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  return true;
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#else
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  return false;
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#endif
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}
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instruction_operand callback_heap::callback_operand(code_block* stub,
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                                                    cell index) {
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  tagged<array> code_template(parent->special_objects[CALLBACK_STUB]);
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  tagged<byte_array> relocation_template(
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      array_nth(code_template.untagged(), 0));
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  relocation_entry entry(relocation_template->data<relocation_entry>()[index]);
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  return instruction_operand(entry, stub, 0);
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}
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void callback_heap::store_callback_operand(code_block* stub, cell index) {
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  parent->store_external_address(callback_operand(stub, index));
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}
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void callback_heap::store_callback_operand(code_block* stub, cell index,
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                                           cell value) {
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  callback_operand(stub, index).store_value(value);
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}
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void callback_heap::update(code_block* stub) {
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  store_callback_operand(stub, setup_seh_p() ? 2 : 1,
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                         (cell)callback_entry_point(stub));
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  stub->flush_icache();
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}
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code_block* callback_heap::add(cell owner, cell return_rewind) {
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  tagged<array> code_template(parent->special_objects[CALLBACK_STUB]);
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  tagged<byte_array> insns(array_nth(code_template.untagged(), 1));
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  cell size = array_capacity(insns.untagged());
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  cell bump = align(size + sizeof(code_block), data_alignment);
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  code_block* stub = allocator->allot(bump);
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  if (!stub) {
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    parent->general_error(ERROR_CALLBACK_SPACE_OVERFLOW,
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                          false_object,
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                          false_object);
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  }
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  stub->header = bump & ~7;
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  stub->owner = owner;
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  stub->parameters = false_object;
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  stub->relocation = false_object;
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  memcpy(stub->entry_point(), insns->data<void>(), size);
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  /* Store VM pointer */
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  store_callback_operand(stub, 0, (cell)parent);
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  cell index;
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  if (setup_seh_p()) {
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    store_callback_operand(stub, 1);
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    index = 1;
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  } else
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    index = 0;
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  /* Store VM pointer */
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  store_callback_operand(stub, index + 2, (cell) parent);
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  /* On x86, the RET instruction takes an argument which depends on
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     the callback's calling convention */
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  if (return_takes_param_p())
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    store_callback_operand(stub, index + 3, return_rewind);
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  update(stub);
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  return stub;
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}
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struct callback_updater {
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  callback_heap* callbacks;
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  explicit callback_updater(callback_heap* callbacks)
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      : callbacks(callbacks) {}
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  void operator()(code_block* stub, cell size) {
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    callbacks->update(stub);
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  }
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};
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void callback_heap::update() {
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  callback_updater updater(this);
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  allocator->iterate(updater);
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}
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/* Allocates memory */
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void factor_vm::primitive_callback() {
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  cell return_rewind = to_cell(ctx->pop());
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  tagged<word> w(ctx->pop());
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  w.untag_check(this);
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  void* func = callbacks->add(w.value(), return_rewind)->entry_point();
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  CODE_TO_FUNCTION_POINTER_CALLBACK(this, func);
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  ctx->push(allot_alien(func));
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}
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void factor_vm::primitive_free_callback() {
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  void* entry_point = alien_offset(ctx->pop());
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  code_block* stub = (code_block*)entry_point - 1;
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  callbacks->allocator->free(stub);
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}
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/* Allocates memory */
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void factor_vm::primitive_callback_room() {
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  allocator_room room = callbacks->allocator->as_allocator_room();
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  ctx->push(tag<byte_array>(byte_array_from_value(&room)));
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}
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}
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