#include <scc_mir.h>

void scc_mir_func_meta_init(scc_mir_func_meta_t *func_meta) {
    func_meta->frame_size = 0;
    func_meta->stack_alignment = 0;
    func_meta->vregs_count = 0;
    scc_vec_init(func_meta->stack_slots);

    // For null stack slot
    scc_vec_push(func_meta->stack_slots, (scc_mir_stack_slot_t){0});
    scc_hashtable_usize_init(&func_meta->vreg2physic);
}

int scc_mir_alloc_vreg(scc_mir_func_t *func) {
    scc_mir_func_meta_t *meta = SCC_MIR_FUNC_META(func);
    return meta->vregs_count++;
}

void scc_mir_vreg_op(const scc_mir_func_t *func, int vreg,
                     scc_mir_operand_t *out) {
    scc_mir_func_meta_t *meta = SCC_MIR_FUNC_META(func);
    isize idx =
        (isize)scc_hashtable_get(&meta->vreg2physic, (void *)(usize)vreg);
    if (idx == 0) {
        out->kind = SCC_MIR_OP_VREG;
        out->vreg = vreg;
    } else if (idx < 0) {
        out->kind = SCC_MIR_OP_PREG;
        out->preg = (int)-idx;
    } else {
        out->kind = SCC_MIR_OP_STACK_SLOT;
        Assert(idx < scc_vec_size(meta->stack_slots));
        out->stack_slot = (int)(usize)idx;
    }
}

void scc_mir_vreg_map2preg(scc_mir_func_t *func, int vreg, int preg) {
    scc_mir_func_meta_t *meta = SCC_MIR_FUNC_META(func);
    isize val =
        (isize)scc_hashtable_get(&meta->vreg2physic, (void *)(usize)vreg);
    if (val != 0) {
        Panic("vreg %d already mapped", vreg);
        return;
    }
    scc_hashtable_set(&meta->vreg2physic, (void *)(usize)vreg,
                      (void *)(usize)(isize)-preg);
}

int scc_mir_vreg_map2slot(scc_mir_func_t *func, int vreg, int size, int align) {
    scc_mir_func_meta_t *meta = SCC_MIR_FUNC_META(func);
    isize val =
        (isize)scc_hashtable_get(&meta->vreg2physic, (void *)(usize)vreg);
    if (val != 0) {
        Panic("vreg %d already mapped", vreg);
        return 0;
    }
    int new_slot = scc_vec_size(meta->stack_slots);
    scc_mir_stack_slot_t s = {
        .slot_id = new_slot, .size = size, .alignment = align, .offset = 0};
    scc_vec_push(meta->stack_slots, s);
    scc_hashtable_set(&meta->vreg2physic, (void *)(usize)vreg,
                      (void *)(usize)new_slot);
    return new_slot;
}