patcher.cpp

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/* src/vm/jit/s390/patcher.cpp - s390 code patching functions

   Copyright (C) 1996-2013
   CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO

   This file is part of CACAO.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.

*/


#include "config.h"

#include <assert.h>
#include <stdint.h>

#include "mm/memory.hpp"
#include "native/native.hpp"

#include "vm/jit/builtin.hpp"
#include "vm/class.hpp"
#include "vm/field.hpp"
#include "vm/initialize.hpp"
#include "vm/options.hpp"
#include "vm/references.hpp"
#include "vm/resolve.hpp"
#include "vm/types.hpp"

#include "vm/jit/patcher-common.hpp"
#include "vm/jit/s390/codegen.hpp"
#include "vm/jit/s390/md-abi.hpp"


#define PATCH_BACK_ORIGINAL_MCODE \
    *((u2 *) pr->mpc) = (u2) pr->mcode;

#define PATCHER_TRACE 


/* patcher_patch_code **********************************************************

   Just patches back the original machine code.

*******************************************************************************/

void patcher_patch_code(patchref_t *pr)
{
    PATCH_BACK_ORIGINAL_MCODE;
}


/* patcher_get_putstatic *******************************************************

   Machine code:

*******************************************************************************/

bool patcher_get_putstatic(patchref_t *pr)
{
    unresolved_field *uf;
    u1               *datap;
    fieldinfo        *fi;

    PATCHER_TRACE;

    /* get stuff from the stack */

    uf    = (unresolved_field *) pr->ref;
    datap = (u1 *)               pr->datap;

    /* get the fieldinfo */

    if (!(fi = resolve_field_eager(uf)))
        return false;

    /* check if the field's class is initialized */

    if (!(fi->clazz->state & CLASS_INITIALIZED))
        if (!initialize_class(fi->clazz))
            return false;

    PATCH_BACK_ORIGINAL_MCODE;

    /* patch the field value's address */

    *((intptr_t *) datap) = (intptr_t) fi->value;

    return true;
}


/* patcher_get_putfield ********************************************************

   Machine code:

*******************************************************************************/

bool patcher_get_putfield(patchref_t *pr)
{
    u1               *ra;
    unresolved_field *uf;
    fieldinfo        *fi;
    s4                disp;

    PATCHER_TRACE;

    /* get stuff from the stack */

    ra    = (u1 *)               pr->mpc;
    uf    = (unresolved_field *) pr->ref;
    disp  =                      pr->disp;

    /* get the fieldinfo */

    if (!(fi = resolve_field_eager(uf)))
        return false;

    PATCH_BACK_ORIGINAL_MCODE;

    /* If there is an operand load before, skip the load size passed in disp (see ICMD_PUTFIELD) */

    ra += disp;

    /* patch correct offset */

    if (fi->type == TYPE_LNG) {
        ASSERT_VALID_DISP(fi->offset + 4);
        /* 2 RX operations, for 2 words; each already contains a 0 or 4 offset. */
        N_RX_SET_DISP(ra, fi->offset + N_RX_GET_DISP(ra));
        ra += SZ_RX;
        N_RX_SET_DISP(ra, fi->offset + N_RX_GET_DISP(ra));
    } else {
        ASSERT_VALID_DISP(fi->offset);
        /* 1 RX operation */
        N_RX_SET_DISP(ra, fi->offset);
    }

    return true;
}

/* patcher_invokestatic_special ************************************************

   Machine code:

*******************************************************************************/

bool patcher_invokestatic_special(patchref_t *pr)
{
    unresolved_method *um;
    u1                *datap;
    methodinfo        *m;

    PATCHER_TRACE;

    /* get stuff from the stack */

    um    = (unresolved_method *) pr->ref;
    datap = (u1 *)                pr->datap;

    /* get the fieldinfo */

    if (!(m = resolve_method_eager(um)))
        return false;

    PATCH_BACK_ORIGINAL_MCODE;

    /* patch stubroutine */

    *((ptrint *) datap) = (ptrint) m->stubroutine;

    return true;
}

/* patcher_invokevirtual *******************************************************

   Machine code:

*******************************************************************************/

bool patcher_invokevirtual(patchref_t *pr)
{
    u1                *ra;
    unresolved_method *um;
    methodinfo        *m;
    s4                 off;

    PATCHER_TRACE;

    /* get stuff from the stack */

    ra    = (u1 *)                pr->mpc;
    um    = (unresolved_method *) pr->ref;

    /* get the fieldinfo */

    if (!(m = resolve_method_eager(um)))
        return false;

    /* patch back original code */

    PATCH_BACK_ORIGINAL_MCODE;

    /* patch vftbl index */


    off = (s4) (OFFSET(vftbl_t, table[0]) +
                                   sizeof(methodptr) * m->vftblindex);

    ASSERT_VALID_DISP(off);

    N_RX_SET_DISP(ra + SZ_RX, off);

    return true;
}


/* patcher_invokeinterface *****************************************************

   Machine code:

*******************************************************************************/

bool patcher_invokeinterface(patchref_t *pr)
{
    u1                *ra;
    unresolved_method *um;
    methodinfo        *m;
    s4                 idx, off;

    PATCHER_TRACE;

    /* get stuff from the stack */

    ra    = (u1 *)                pr->mpc;
    um    = (unresolved_method *) pr->ref;

    /* get the fieldinfo */

    if (!(m = resolve_method_eager(um)))
        return false;

    /* patch back original code */

    PATCH_BACK_ORIGINAL_MCODE;

    /* get interfacetable index */

    idx = (s4) (OFFSET(vftbl_t, interfacetable[0]) -
        sizeof(methodptr) * m->clazz->index);

    ASSERT_VALID_IMM(idx);

    /* get method offset */

    off =
        (s4) (sizeof(methodptr) * (m - m->clazz->methods));

    ASSERT_VALID_DISP(off);

    /* patch them */

    N_RI_SET_IMM(ra + SZ_L, idx);
    N_RX_SET_DISP(ra + SZ_L + SZ_LHI + SZ_L, off);

    return true;
}


/* patcher_resolve_classref_to_flags *******************************************

   CHECKCAST/INSTANCEOF:

   <patched call position>

*******************************************************************************/

bool patcher_resolve_classref_to_flags(patchref_t *pr)
{
    constant_classref *cr;
    u1                *datap;
    classinfo         *c;

    PATCHER_TRACE;

    /* get stuff from the stack */

    cr    = (constant_classref *) pr->ref;
    datap = (u1 *)                pr->datap;

    /* get the fieldinfo */

    if (!(c = resolve_classref_eager(cr)))
        return false;

    PATCH_BACK_ORIGINAL_MCODE;

    /* patch class flags */

    *((s4 *) datap) = (s4) c->flags;

    return true;
}

/* patcher_resolve_classref_to_classinfo ***************************************

   ACONST:
   MULTIANEWARRAY:
   ARRAYCHECKCAST:

*******************************************************************************/

bool patcher_resolve_classref_to_classinfo(patchref_t *pr)
{
    constant_classref *cr;
    u1                *datap;
    classinfo         *c;

    PATCHER_TRACE;

    /* get stuff from the stack */

    cr    = (constant_classref *) pr->ref;
    datap = (u1 *)                pr->datap;

    /* get the classinfo */

    if (!(c = resolve_classref_eager(cr)))
        return false;

    PATCH_BACK_ORIGINAL_MCODE;

    /* patch the classinfo pointer */

    *((ptrint *) datap) = (ptrint) c;

    return true;
}

/* patcher_resolve_classref_to_vftbl *******************************************

   CHECKCAST (class):
   INSTANCEOF (class):

*******************************************************************************/

bool patcher_resolve_classref_to_vftbl(patchref_t *pr)
{
    constant_classref *cr;
    u1                *datap;
    classinfo         *c;

    PATCHER_TRACE;

    /* get stuff from the stack */

    cr    = (constant_classref *) pr->ref;
    datap = (u1 *)                pr->datap;

    /* get the fieldinfo */

    if (!(c = resolve_classref_eager(cr)))
        return false;

    PATCH_BACK_ORIGINAL_MCODE;

    /* patch super class' vftbl */

    *((ptrint *) datap) = (ptrint) c->vftbl;

    return true;
}

/* patcher_checkcast_instanceof_interface **************************************

   Machine code:

*******************************************************************************/

bool patcher_checkcast_instanceof_interface(patchref_t *pr)
{

    u1                *ra;
    constant_classref *cr;
    classinfo         *c;

    PATCHER_TRACE;

    /* get stuff from the stack */

    ra    = (u1 *)                pr->mpc;
    cr    = (constant_classref *) pr->ref;

    /* get the fieldinfo */

    if (!(c = resolve_classref_eager(cr)))
        return false;

    /* patch back original code */

    PATCH_BACK_ORIGINAL_MCODE;

    /* patch super class index */

    /* From here, split your editor and open codegen.c */

    switch (N_RX_GET_REG(ra)) {
        case REG_ITMP1: 
            /* First M_ALD is into ITMP1 */
            /* INSTANCEOF code */

            N_RI_SET_IMM(ra + SZ_L + SZ_L, - c->index);
            N_RI_SET_IMM(
                ra + SZ_L + SZ_L + SZ_AHI + SZ_BRC,
                (int16_t)(OFFSET(vftbl_t, interfacetable[0]) - c->index * sizeof(methodptr*))
            );
            break;

        case REG_ITMP2:
            /* First M_ALD is into ITMP2 */
            /* CHECKCAST code */

            N_RI_SET_IMM(ra + SZ_L + SZ_L, - c->index);
            N_RI_SET_IMM(
                ra + SZ_L + SZ_L + SZ_AHI + SZ_BRC + SZ_ILL,
                (int16_t)(OFFSET(vftbl_t, interfacetable[0]) - c->index * sizeof(methodptr*))
            );
            break;

        default:
            assert(0);
            break;
    }

    return true;
}


/*
 * These are local overrides for various environment variables in Emacs.
 * Please do not remove this and leave it at the end of the file, where
 * Emacs will automagically detect them.
 * ---------------------------------------------------------------------
 * Local variables:
 * mode: c++
 * indent-tabs-mode: t
 * c-basic-offset: 4
 * tab-width: 4
 * End:
 * vim:noexpandtab:sw=4:ts=4:
 */