147 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			C++
		
	
	
			
		
		
	
	
			147 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			C++
		
	
	
#include "master.hpp"
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namespace factor
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{
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callstack *factor_vm::allot_callstack(cell size)
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{
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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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{
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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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	{
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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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cell factor_vm::capture_callstack(context *ctx)
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{
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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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void factor_vm::primitive_callstack()
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{
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	ctx->push(capture_callstack(ctx));
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}
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void factor_vm::primitive_callstack_for()
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{
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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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{
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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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	explicit stack_frame_accumulator(factor_vm *parent_)
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		: parent(parent_), frames(parent_) {}
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	void operator()(void *frame_top, cell frame_size, code_block *owner, void *addr)
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	{
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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 { cell cells[3]; };
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void factor_vm::primitive_callstack_to_array()
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{
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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(
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		(stack_frame_in_array*)accum.frames.elements->data(),
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		(stack_frame_in_array*)(accum.frames.elements->data() + 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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{
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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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{
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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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void factor_vm::primitive_set_innermost_stack_frame_quot()
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{
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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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void factor_vm::primitive_callstack_bounds()
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{
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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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