143 lines
		
	
	
		
			4.6 KiB
		
	
	
	
		
			C++
		
	
	
			
		
		
	
	
			143 lines
		
	
	
		
			4.6 KiB
		
	
	
	
		
			C++
		
	
	
#include "master.hpp"
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namespace factor {
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/* Allocates memory (allot) */
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callstack* factor_vm::allot_callstack(cell size) {
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  callstack* stack = allot<callstack>(callstack_object_size(size));
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  stack->length = tag_fixnum(size);
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  return stack;
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}
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/* We ignore the two topmost frames, the 'callstack' primitive
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frame itself, and the frame calling the 'callstack' primitive,
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so that set-callstack doesn't get stuck in an infinite loop.
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This means that if 'callstack' is called in tail position, we
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will have popped a necessary frame... however this word is only
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called by continuation implementation, and user code shouldn't
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be calling it at all, so we leave it as it is for now. */
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void* factor_vm::second_from_top_stack_frame(context* ctx) {
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  void* frame_top = ctx->callstack_top;
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  for (cell i = 0; i < 2; ++i) {
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    void* pred = frame_predecessor(frame_top);
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    if (pred >= ctx->callstack_bottom)
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      return frame_top;
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    frame_top = pred;
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  }
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  return frame_top;
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}
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/* Allocates memory (allot_callstack) */
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cell factor_vm::capture_callstack(context* ctx) {
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  void* top = second_from_top_stack_frame(ctx);
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  void* bottom = ctx->callstack_bottom;
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  fixnum size = std::max((fixnum)0, (fixnum)bottom - (fixnum)top);
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  callstack* stack = allot_callstack(size);
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  memcpy(stack->top(), top, size);
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  return tag<callstack>(stack);
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}
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/* Allocates memory (capture_callstack) */
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void factor_vm::primitive_callstack() { ctx->push(capture_callstack(ctx)); }
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/* Allocates memory (capture_callstack) */
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void factor_vm::primitive_callstack_for() {
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  context* other_ctx = (context*)pinned_alien_offset(ctx->peek());
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  ctx->replace(capture_callstack(other_ctx));
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}
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void* factor_vm::frame_predecessor(void* frame_top) {
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  void* addr = frame_return_address((void*)frame_top);
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  FACTOR_ASSERT(addr != 0);
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  code_block* owner = code->code_block_for_address((cell)addr);
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  cell frame_size = owner->stack_frame_size_for_address((cell)addr);
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  return (void*)((char*)frame_top + frame_size);
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}
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struct stack_frame_accumulator {
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  factor_vm* parent;
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  growable_array frames;
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  /* Allocates memory (frames is a growable_array, constructor allocates) */
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  explicit stack_frame_accumulator(factor_vm* parent)
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      : parent(parent), frames(parent) {}
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  /* Allocates memory (frames.add()) */
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  void operator()(void* frame_top, cell frame_size, code_block* owner,
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                  void* addr) {
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    data_root<object> executing_quot(owner->owner_quot(), parent);
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    data_root<object> executing(owner->owner, parent);
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    data_root<object> scan(owner->scan(parent, addr), parent);
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    frames.add(executing.value());
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    frames.add(executing_quot.value());
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    frames.add(scan.value());
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  }
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};
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struct stack_frame_in_array {
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  cell cells[3];
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};
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void factor_vm::primitive_callstack_to_array() {
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  data_root<callstack> callstack(ctx->peek(), this);
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  stack_frame_accumulator accum(this);
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  iterate_callstack_object(callstack.untagged(), accum);
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  /* The callstack iterator visits frames in reverse order (top to bottom) */
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  std::reverse((stack_frame_in_array*)accum.frames.elements->data(),
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               (stack_frame_in_array*)(accum.frames.elements->data() +
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                                       accum.frames.count));
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  accum.frames.trim();
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  ctx->replace(accum.frames.elements.value());
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}
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/* Some primitives implementing a limited form of callstack mutation.
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Used by the single stepper. */
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void factor_vm::primitive_innermost_stack_frame_executing() {
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  callstack* stack = untag_check<callstack>(ctx->peek());
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  void* frame = stack->top();
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  void* addr = frame_return_address(frame);
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  ctx->replace(code->code_block_for_address((cell)addr)->owner_quot());
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}
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void factor_vm::primitive_innermost_stack_frame_scan() {
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  callstack* stack = untag_check<callstack>(ctx->peek());
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  void* frame = stack->top();
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  void* addr = frame_return_address(frame);
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  ctx->replace(code->code_block_for_address((cell)addr)->scan(this, addr));
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}
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/* Allocates memory (jit_compile_quot) */
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void factor_vm::primitive_set_innermost_stack_frame_quot() {
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  data_root<callstack> stack(ctx->pop(), this);
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  data_root<quotation> quot(ctx->pop(), this);
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  stack.untag_check(this);
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  quot.untag_check(this);
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  jit_compile_quot(quot.value(), true);
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  void* inner = stack->top();
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  void* addr = frame_return_address(inner);
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  code_block* block = code->code_block_for_address((cell)addr);
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  cell offset = block->offset(addr);
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  set_frame_return_address(inner, (char*)quot->entry_point + offset);
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}
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/* Allocates memory (allot_alien) */
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void factor_vm::primitive_callstack_bounds() {
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  ctx->push(allot_alien((void*)ctx->callstack_seg->start));
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  ctx->push(allot_alien((void*)ctx->callstack_seg->end));
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}
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}
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