/* Enter a block. */
PERL_CONTEXT * Perl_PushBlock(U8 t, SV** sp, U8 gimme) {
    PERL_CONTEXT *cx;
    HV *new_dynascope;
    PERL_ARGS_ASSERT_PUSHBLOCK;
    CXINC;
    cx = &cxstack[cxstack_ix];
    cx->cx_type		= t;
    cx->blk_oldsp		= sp - PL_stack_base;
    cx->blk_oldcop		= PL_curcop;
    cx->blk_oldop		= PL_op;
    cx->blk_oldmarksp	= PL_markstack_ptr - PL_markstack;
    cx->blk_oldscopesp	= PL_scopestack_ix;
    cx->blk_oldpm		= PL_curpm;
    cx->blk_gimme		= gimme;
    cx->blk_dynascope       = PL_dynamicscope;

    new_dynascope = newHV();
    if (PL_dynamicscope)
        (void)hv_stores( new_dynascope, "parent", newRV(PL_dynamicscope) );
    (void)hv_stores( new_dynascope, "onleave", avTsv(newAV()) );
    PL_dynamicscope = hvTsv(new_dynascope);

    DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n",
            (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); );
    return cx;
}

PERL_CONTEXT * Perl_PopBlock() {
    PERL_CONTEXT * cx;
    SV** onleave_ref = hv_fetchs(svThv(PL_dynamicscope), "onleave", 0);
    if (onleave_ref && SvAVOK(*onleave_ref)) {
        AV* onleave = svTav(*onleave_ref);
        while (av_len(onleave) >= 0) {
            SV* onleave_item = av_pop(onleave);
            PUSHMARK(PL_stack_sp);
            call_sv(onleave_item, G_DISCARD|G_VOID);
        }
    }

    cx = &cxstack[cxstack_ix--];
    PL_curcop	 = cx->blk_oldcop;
    PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp;
    PL_scopestack_ix = cx->blk_oldscopesp;
    SVcpSTEAL(PL_dynamicscope, cx->blk_dynascope);

    DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",
            (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]) );
    return cx;
}

void Perl_cx_free_eval(PERL_CONTEXT* cx) {
    PERL_ARGS_ASSERT_CX_FREE_EVAL;
    PL_in_eval = CxOLD_IN_EVAL(cx);
    ROOTOPcpNULL(PL_eval_root);
    PL_eval_root = cx->blk_eval.old_eval_root;
    if (cx->blk_eval.old_namesv)
        sv_2mortal(cx->blk_eval.old_namesv);
}