factor/vm/callstack.cpp

133 lines
4.3 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 = 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() { ctx->push(capture_callstack(ctx)); }
/* 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));
}
cell factor_vm::frame_predecessor(cell frame_top) {
cell addr = *(cell*)frame_top;
FACTOR_ASSERT(addr != 0);
code_block* owner = code->code_block_for_address(addr);
cell frame_size = owner->stack_frame_size_for_address(addr);
return frame_top + frame_size;
}
struct stack_frame_in_array {
cell cells[3];
};
/* 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);
/* The callstack iterator visits frames in reverse order (top to bottom) */
std::reverse((stack_frame_in_array*)frames.elements->data(),
(stack_frame_in_array*)(frames.elements->data() +
frames.count));
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);
stack.untag_check(this);
quot.untag_check(this);
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;
}
/* Allocates memory (allot_alien) */
void factor_vm::primitive_callstack_bounds() {
ctx->push(allot_alien((void*)ctx->callstack_seg->start));
ctx->push(allot_alien((void*)ctx->callstack_seg->end));
}
}