/* This file contains a number of functions that do lookups of data held in

 * data structures outside of the realm of spesh. We need to be very careful

 * how we do these, in various cases. For example, in the past we had cases

 * where we tried to look up a method, which in turn triggered method cache

 * deserialization, which acquired a mutex, which would block for GC and so

 * could end up with a collection taking place while spesh was working. This

 * broke the "no GC during spesh" invariant. */

#include "moar.h"

/* Tries to get the HOW (meta-object) of an object - but only if it's already

 * available (e.g. deserialized). In the case it's not, returns NULL. */

MVMObject * MVM_spesh_try_get_how(MVMThreadContext *tc, MVMObject *obj) {

    return STABLE(obj)->HOW;

}

/* Tries to look up the method using the method cache, provided that the

 * method cache has already been deserialized. */

MVMObject * MVM_spesh_try_find_method(MVMThreadContext *tc, MVMObject *obj, MVMString *name) {

    return STABLE(obj)->method_cache

        ? MVM_6model_find_method_cache_only(tc, obj, name)

        : NULL;

}

/* Tries to check if the method exists on the object using the method cache,

 * provided the method cache has already been deserialized. */

MVMint64 MVM_spesh_try_can_method(MVMThreadContext *tc, MVMObject *obj, MVMString *name) {

    return STABLE(obj)->method_cache

        ? MVM_6model_can_method_cache_only(tc, obj, name)

        : -1;

}

MVMint8 MVM_spesh_get_reg_type(MVMThreadContext *tc, MVMSpeshGraph *sg, MVMuint16 reg) {

    return sg->local_types ? sg->local_types[reg] : sg->sf->body.local_types[reg];

}

MVMint8 MVM_spesh_get_lex_type(MVMThreadContext *tc, MVMSpeshGraph *sg, MVMuint16 outers, MVMuint16 idx) {

    if (outers == 0) {

        return sg->lexical_types ? sg->lexical_types[idx] : sg->sf->body.lexical_types[idx];

    } else {

        MVMStaticFrame *sf;

        for (sf = sg->sf; sf != NULL && outers--; sf = sf->body.outer);

        return sf->body.lexical_types[idx];

    }

}