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#ifndef FRAME_LAYOUT_H
#include "forkable_stack.h"
#include "bytecode.h"
struct closure {
struct bytecode* bc;
stack_idx env;
};
struct continuation {
struct bytecode* bc;
stack_idx env;
uint16_t* retaddr;
// FIXME: probably not necessary as a separate field
int is_backtrack_frame;
};
typedef union frame_elem {
FORKABLE_STACK_HEADER;
struct continuation cont;
struct closure closure;
jv jsonval;
} *frame_ptr;
/*
* Frame layout
* fr[0] - FORKABLE_STACK_HEADER (next pointer)
* fr[1] - self (used to store return addresses, etc)
* fr[2...nclosures+2] - closure params
* fr[nclosures+2..nclosures+nlocals+2] - local variables
*/
static int frame_size(struct bytecode* bc) {
return sizeof(union frame_elem) * (bc->nclosures + bc->nlocals + 2);
}
static struct continuation* frame_self(frame_ptr fr) {
return &fr[1].cont;
}
static struct closure* frame_closure_arg(frame_ptr fr, int closure) {
assert(closure >= 0);
assert(closure < frame_self(fr)->bc->nclosures);
return &fr[2+closure].closure;
}
static jv* frame_local_var(frame_ptr fr, int var) {
assert(var >= 0);
assert(var < frame_self(fr)->bc->nlocals);
return &fr[2 + frame_self(fr)->bc->nclosures + var].jsonval;
}
static frame_ptr frame_current(struct forkable_stack* stk) {
frame_ptr fp = forkable_stack_peek(stk);
if (forkable_stack_peek_next(stk, fp)) {
struct bytecode* bc = frame_self(forkable_stack_peek_next(stk, fp))->bc;
assert(frame_self(fp)->retaddr >= bc->code && frame_self(fp)->retaddr < bc->code + bc->codelen);
} else {
assert(frame_self(fp)->retaddr == 0);
}
return fp;
}
static struct bytecode* frame_current_bytecode(struct forkable_stack* stk) {
return frame_self(frame_current(stk))->bc;
}
static uint16_t** frame_current_retaddr(struct forkable_stack* stk) {
return &frame_self(frame_current(stk))->retaddr;
}
static frame_ptr frame_get_parent(struct forkable_stack* stk, frame_ptr fr) {
return forkable_stack_from_idx(stk, frame_self(fr)->env);
}
static frame_ptr frame_get_level(struct forkable_stack* stk, frame_ptr fr, int level) {
for (int i=0; i<level; i++) {
fr = frame_get_parent(stk, fr);
}
return fr;
}
static frame_ptr frame_push(struct forkable_stack* stk, struct closure cl, uint16_t* retaddr) {
frame_ptr fp = forkable_stack_push(stk, frame_size(cl.bc));
struct continuation* cc = frame_self(fp);
cc->bc = cl.bc;
cc->env = cl.env;
cc->retaddr = retaddr;
cc->is_backtrack_frame = 0;
for (int i=0; i<cl.bc->nlocals; i++) {
*frame_local_var(fp, i) = jv_invalid();
}
return fp;
}
static frame_ptr frame_push_backtrack(struct forkable_stack* stk, uint16_t* retaddr) {
struct continuation cc = *frame_self(frame_current(stk));
frame_ptr fp = forkable_stack_push(stk, sizeof(union frame_elem) * 2);
assert(!cc.is_backtrack_frame);
cc.is_backtrack_frame = 1;
cc.retaddr = retaddr;
*frame_self(fp) = cc;
return fp;
}
static void frame_pop(struct forkable_stack* stk) {
frame_ptr fp = frame_current(stk);
if (forkable_stack_pop_will_free(stk) &&
!frame_self(fp)->is_backtrack_frame) {
int nlocals = frame_self(fp)->bc->nlocals;
for (int i=0; i<nlocals; i++) {
jv_free(*frame_local_var(fp, i));
}
}
forkable_stack_pop(stk);
}
#endif