stackmap.cpp

Go to the documentation of this file.

/* src/vm/stackmap.c - class attribute StackMapTable

   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 "vm/types.hpp"

#include "mm/dumpmemory.hpp"

#include "vm/exceptions.hpp"
#include "vm/stackmap.hpp"
#include "vm/statistics.hpp"
#include "vm/options.hpp"
#include "vm/suck.hpp"

STAT_DECLARE_VAR(int,size_stack_map,0)

struct classinfo;

using namespace cacao;


/* stackmap_get_verification_type_info *****************************************

   union verification_type_info {
       Top_variable_info;
       Integer_variable_info;
       Float_variable_info;
       Long_variable_info;
       Double_variable_info;
       Null_variable_info;
       UninitializedThis_variable_info;
       Object_variable_info;
       Uninitialized_variable_info;
   }

   Top_variable_info {
       u1 tag = ITEM_Top;  // 0
   }

   Integer_variable_info {
       u1 tag = ITEM_Integer;  // 1
   }

   Float_variable_info {
       u1 tag = ITEM_Float;  // 2
   }

   Long_variable_info {
       u1 tag = ITEM_Long;  // 4
   }

   Double_variable_info {
       u1 tag = ITEM_Double;  // 3
   }

   Null_variable_info {
       u1 tag = ITEM_Null;  // 5
   }

   UninitializedThis_variable_info {
       u1 tag = ITEM_UninitializedThis;  // 6
   }

   Object_variable_info {
       u1 tag = ITEM_Object;  // 7
       u2 cpool_index;
   }

   Uninitialized_variable_info {
       u1 tag = ITEM_Uninitialized;  // 8
       u2 offset;
   }

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

static bool stackmap_get_verification_type_info(ClassBuffer& cb, verification_type_info_t *verification_type_info)
{
    /* get verification type */

    if (!cb.check_size(1))
        return false;

    verification_type_info->tag = cb.read_u1();

    /* process the tag */

    switch (verification_type_info->tag) {
    case ITEM_Top:
    case ITEM_Integer:
    case ITEM_Float:
    case ITEM_Long:
    case ITEM_Double:
    case ITEM_Null:
    case ITEM_UninitializedThis:
        break;

    case ITEM_Object:
        /* get constant pool index */

        if (!cb.check_size(2))
            return false;

        verification_type_info->Object_variable_info.cpool_index = cb.read_u2();
        break;

    case ITEM_Uninitialized:
        /* get offset */

        if (!cb.check_size(2))
            return false;

        verification_type_info->Uninitialized_variable_info.offset = cb.read_u2();
        break;
    }

    return true;
}


/* stackmap_get_same_locals_1_stack_item_frame *********************************

   same_locals_1_stack_item_frame {
       u1 frame_type = SAME_LOCALS_1_STACK_ITEM;  // 64-127
       verification_type_info stack[1];
   }

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

static bool stackmap_get_same_locals_1_stack_item_frame(ClassBuffer& cb, stack_map_frame_t *stack_map_frame)
{
    same_locals_1_stack_item_frame_t *same_locals_1_stack_item_frame;

    /* for convenience */

    same_locals_1_stack_item_frame =
        &(stack_map_frame->same_locals_1_stack_item_frame);

    if (!stackmap_get_verification_type_info(cb, &(same_locals_1_stack_item_frame->stack[0])))
        return false;

    return true;
}


/* stackmap_get_same_locals_1_stack_item_frame_extended ************************

   same_locals_1_stack_item_frame_extended {
       u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED;  // 247
       u2 offset_delta;
       verification_type_info stack[1];
   }

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

static bool stackmap_get_same_locals_1_stack_item_frame_extended(ClassBuffer& cb, stack_map_frame_t *stack_map_frame)
{
    same_locals_1_stack_item_frame_extended_t *same_locals_1_stack_item_frame_extended;

    /* for convenience */

    same_locals_1_stack_item_frame_extended =
        &(stack_map_frame->same_locals_1_stack_item_frame_extended);

    /* check buffer size */

    if (!cb.check_size(2))
        return false;

    /* get offset delta */

    same_locals_1_stack_item_frame_extended->offset_delta = cb.read_u2();

    /* process stack */

    if (!stackmap_get_verification_type_info(cb, &(same_locals_1_stack_item_frame_extended->stack[0])))
        return false;

    return true;
}


/* stackmap_get_chop_frame *****************************************************

   chop_frame {
       u1 frame_type = CHOP_FRAME;  // 248-250
       u2 offset_delta;
   }

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

static bool stackmap_get_chop_frame(ClassBuffer& cb, stack_map_frame_t *stack_map_frame)
{
    chop_frame_t *chop_frame;

    /* for convenience */

    chop_frame = &(stack_map_frame->chop_frame);

    /* check buffer size */

    if (!cb.check_size(2))
        return false;

    /* get offset delta */

    chop_frame->offset_delta = cb.read_u2();

    return true;
}


/* stackmap_get_same_frame_extended ********************************************

   same_frame_extended {
       u1 frame_type = SAME_FRAME_EXTENDED;  // 251
       u2 offset_delta;
   }

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

static bool stackmap_get_same_frame_extended(ClassBuffer& cb,
                                             stack_map_frame_t *stack_map_frame)
{
    same_frame_extended_t *same_frame_extended;

    /* for convenience */

    same_frame_extended = &(stack_map_frame->same_frame_extended);

    /* check buffer size */

    if (!cb.check_size(2))
        return false;

    /* get offset delta */

    same_frame_extended->offset_delta = cb.read_u2();

    return true;
}


/* stackmap_get_append_frame ***************************************************

   append_frame {
       u1 frame_type = APPEND_FRAME;  // 252-254
       u2 offset_delta;
       verification_type_info locals[frame_Type - 251];
   }

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

static bool stackmap_get_append_frame(ClassBuffer& cb,
                                      stack_map_frame_t *stack_map_frame)
{
    append_frame_t *append_frame;
    s4              number_of_locals;
    s4              i;

    /* for convenience */

    append_frame = &(stack_map_frame->append_frame);

    /* check buffer size */

    if (!cb.check_size(2))
        return false;

    /* get offset delta */

    append_frame->offset_delta = cb.read_u2();

    /* allocate locals array */

    number_of_locals = append_frame->frame_type - 251;

    append_frame->locals = DMNEW(verification_type_info_t, number_of_locals);

    /* process all locals */

    for (i = 0; i < number_of_locals; i++)
        if (!stackmap_get_verification_type_info(cb, &(append_frame->locals[i])))
            return false;

    return true;
}


/* stackmap_get_full_frame *****************************************************

   full_frame {
       u1 frame_type = FULL_FRAME;
       u2 offset_delta;
       u2 number_of_locals;
       verification_type_info locals[number_of_locals];
       u2 number_of_stack_items;
       verification_type_info stack[number_of_stack_items];
   }

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

static bool stackmap_get_full_frame(ClassBuffer& cb,
                                    stack_map_frame_t *stack_map_frame)
{
    full_frame_t *full_frame;
    s4 i;

    /* for convenience */

    full_frame = &(stack_map_frame->full_frame);

    /* check buffer size */

    if (!cb.check_size(2 + 2))
        return false;

    /*  get offset delta */

    stack_map_frame->full_frame.offset_delta = cb.read_u2();

    /* get number of locals */

    full_frame->number_of_locals = cb.read_u2();

    /* allocate locals array */

    full_frame->locals =
        DMNEW(verification_type_info_t, full_frame->number_of_locals);

    /* process all locals */

    for (i = 0; i < full_frame->number_of_locals; i++)
        if (!stackmap_get_verification_type_info(cb, &(full_frame->locals[i])))
            return false;

    /* get number of stack items */

    if (!cb.check_size(2))
        return false;

    full_frame->number_of_stack_items = cb.read_u2();

    /* allocate stack array */

    full_frame->stack =
        DMNEW(verification_type_info_t, full_frame->number_of_stack_items);

    /* process all stack items */

    for (i = 0; i < full_frame->number_of_stack_items; i++)
        if (!stackmap_get_verification_type_info(cb, &(full_frame->stack[i])))
            return false;

    return true;
}


/* stackmap_load_attribute_stackmaptable ***************************************

   stack_map {
       u2 attribute_name_index;
       u4 attribute_length;
       u2 number_of_entries;
       stack_map_frame entries[number_of_entries];
   }

   union stack_map_frame {
       same_frame;
       same_locals_1_stack_item_frame;
       same_locals_1_stack_item_frame_extended;
       chop_frame;
       same_frame_extended;
       append_frame;
       full_frame;
   }

   same_frame {
       u1 frame_type = SAME;  // 0-63
   }

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

bool stackmap_load_attribute_stackmaptable(ClassBuffer& cb, methodinfo *m)
{
    classinfo       *c;
    stack_map_t     *stack_map;
    s4               i;
    u1               frame_type;

    /* get classinfo */

    c = cb.get_class();

    /* allocate stack map structure */

    stack_map = DNEW(stack_map_t);

    STATISTICS(size_stack_map += sizeof(stack_map_t));

    /* check buffer size */

    if (!cb.check_size(4 + 2))
        return false;

    /* attribute_length */

    stack_map->attribute_length = cb.read_u4();

    if (!cb.check_size(stack_map->attribute_length))
        return false;

    /* get number of entries */

    stack_map->number_of_entries = cb.read_u2();

    /* process all entries */

    stack_map->entries = DMNEW(stack_map_frame_t, stack_map->number_of_entries);

    for (i = 0; i < stack_map->number_of_entries; i++) {
        /* get the frame type */

        frame_type = cb.read_u1();

        stack_map->entries[i].frame_type = frame_type;

        /* process frame */

        if (frame_type <= FRAME_TYPE_SAME) {
            /* same_frame */
        }
        else if (frame_type <= FRAME_TYPE_SAME_LOCALS_1_STACK_ITEM) {
            /* same_locals_1_stack_item_frame */

            if (!stackmap_get_same_locals_1_stack_item_frame(cb, &(stack_map->entries[i])))
                return false;
        }
        else if (frame_type <= FRAME_TYPE_RESERVED) {
            /* reserved */

            exceptions_throw_classformaterror(c, "reserved frame type");
            return false;
        }
        else if (frame_type == FRAME_TYPE_SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
            /* same_locals_1_stack_item_frame_extended */

            if (!stackmap_get_same_locals_1_stack_item_frame_extended(cb, &(stack_map->entries[i])))
                return false;
        }
        else if (frame_type <= FRAME_TYPE_CHOP) {
            /* chop_frame */

            if (!stackmap_get_chop_frame(cb, &(stack_map->entries[i])))
                return false;
        }
        else if (frame_type == FRAME_TYPE_SAME_FRAME_EXTENDED) {
            /* same_frame_extended */

            if (!stackmap_get_same_frame_extended(cb, &(stack_map->entries[i])))
                return false;
        }
        else if (frame_type <= FRAME_TYPE_APPEND) {
            /* append_frame */

            if (!stackmap_get_append_frame(cb, &(stack_map->entries[i])))
                return false;
        }
        else if (frame_type == FRAME_TYPE_FULL_FRAME) {
            /* full_frame */

            if (!stackmap_get_full_frame(cb, &(stack_map->entries[i])))
                return false;
        }
    }

    /* store stack map in method structure */

#if 0
    /* currently not used */

    m->stack_map = stack_map;
#endif

    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:
 */