factor/vm/callstack.cpp

108 lines
3.4 KiB
C++

#include "master.hpp"
namespace factor {
// Allocates memory (allot)
callstack* factor_vm::allot_callstack(cell size) {
callstack* stack = allot<callstack>(callstack_object_size(size));
stack->length = tag_fixnum(size);
return stack;
}
// We ignore the two topmost frames, the 'callstack' primitive
// frame itself, and the frame calling the 'callstack' primitive,
// so that set-callstack doesn't get stuck in an infinite loop.
// This means that if 'callstack' is called in tail position, we
// will have popped a necessary frame... however this word is only
// called by continuation implementation, and user code shouldn't
// be calling it at all, so we leave it as it is for now.
cell factor_vm::second_from_top_stack_frame(context* ctx) {
cell frame_top = ctx->callstack_top;
for (cell i = 0; i < 2; ++i) {
cell pred = code->frame_predecessor(frame_top);
if (pred >= ctx->callstack_bottom)
return frame_top;
frame_top = pred;
}
return frame_top;
}
// Allocates memory (allot_callstack)
cell factor_vm::capture_callstack(context* ctx) {
cell top = second_from_top_stack_frame(ctx);
cell bottom = ctx->callstack_bottom;
fixnum size = std::max((cell)0, bottom - top);
callstack* stack = allot_callstack(size);
memcpy(stack->top(), (void *)top, size);
return tag<callstack>(stack);
}
// Allocates memory (capture_callstack)
void factor_vm::primitive_callstack_for() {
context* other_ctx = (context*)pinned_alien_offset(ctx->peek());
ctx->replace(capture_callstack(other_ctx));
}
// Allocates memory (frames.trim()), iterate_callstack_object()
void factor_vm::primitive_callstack_to_array() {
data_root<callstack> callstack(ctx->peek(), this);
// Allocates memory here.
growable_array frames(this);
auto stack_frame_accumulator = [&](cell frame_top,
cell size,
code_block* owner,
cell addr) {
data_root<object> executing_quot(owner->owner_quot(), this);
data_root<object> executing(owner->owner, this);
data_root<object> scan(owner->scan(this, addr), this);
frames.add(executing.value());
frames.add(executing_quot.value());
frames.add(scan.value());
};
iterate_callstack_object(callstack.untagged(), stack_frame_accumulator);
frames.trim();
ctx->replace(frames.elements.value());
}
// Some primitives implementing a limited form of callstack mutation.
// Used by the single stepper.
void factor_vm::primitive_innermost_stack_frame_executing() {
callstack* stack = untag_check<callstack>(ctx->peek());
void* frame = stack->top();
cell addr = *(cell*)frame;
ctx->replace(code->code_block_for_address(addr)->owner_quot());
}
void factor_vm::primitive_innermost_stack_frame_scan() {
callstack* stack = untag_check<callstack>(ctx->peek());
void* frame = stack->top();
cell addr = *(cell*)frame;
ctx->replace(code->code_block_for_address(addr)->scan(this, addr));
}
// Allocates memory (jit_compile_quotation)
void factor_vm::primitive_set_innermost_stack_frame_quotation() {
data_root<callstack> stack(ctx->pop(), this);
data_root<quotation> quot(ctx->pop(), this);
check_tagged(stack);
check_tagged(quot);
jit_compile_quotation(quot.value(), true);
void* inner = stack->top();
cell addr = *(cell*)inner;
code_block* block = code->code_block_for_address(addr);
cell offset = block->offset(addr);
*(cell*)inner = quot->entry_point + offset;
}
}