1 /*

     2  * Copyright (C) 2008 Apple Inc. All rights reserved.

     3  * Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>

     4  *

     5  * Redistribution and use in source and binary forms, with or without

     6  * modification, are permitted provided that the following conditions

     7  * are met:

     8  *

     9  * 1.  Redistributions of source code must retain the above copyright

    10  *     notice, this list of conditions and the following disclaimer.

    11  * 2.  Redistributions in binary form must reproduce the above copyright

    12  *     notice, this list of conditions and the following disclaimer in the

    13  *     documentation and/or other materials provided with the distribution.

    14  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of

    15  *     its contributors may be used to endorse or promote products derived

    16  *     from this software without specific prior written permission.

    17  *

    18  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY

    19  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

    20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

    21  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY

    22  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

    23  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

    24  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

    25  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

    26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

    27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    28  */

    29 

    30 #ifndef JumpTable_h

    31 #define JumpTable_h

    32 

    33 #include "MacroAssembler.h"

    34 #include "UString.h"

    35 #include <wtf/HashMap.h>

    36 #include <wtf/Vector.h>

    37 

    38 namespace JSC {

    39 

    40     struct OffsetLocation {

    41         int32_t branchOffset;

    42 #if ENABLE(JIT)

    43         CodeLocationLabel ctiOffset;

    44 #endif

    45     };

    46 

    47     struct StringJumpTable {

    48         typedef HashMap<RefPtr<UString::Rep>, OffsetLocation> StringOffsetTable;

    49         StringOffsetTable offsetTable;

    50 #if ENABLE(JIT)

    51         CodeLocationLabel ctiDefault; // FIXME: it should not be necessary to store this.

    52 #endif

    53 

    54         inline int32_t offsetForValue(UString::Rep* value, int32_t defaultOffset)

    55         {

    56             StringOffsetTable::const_iterator end = offsetTable.end();

    57             StringOffsetTable::const_iterator loc = offsetTable.find(value);

    58             if (loc == end)

    59                 return defaultOffset;

    60             return loc->second.branchOffset;

    61         }

    62 

    63 #if ENABLE(JIT)

    64         inline CodeLocationLabel ctiForValue(UString::Rep* value)

    65         {

    66             StringOffsetTable::const_iterator end = offsetTable.end();

    67             StringOffsetTable::const_iterator loc = offsetTable.find(value);

    68             if (loc == end)

    69                 return ctiDefault;

    70             return loc->second.ctiOffset;

    71         }

    72 #endif

    73     };

    74 

    75     struct SimpleJumpTable {

    76         // FIXME: The two Vectors can be combind into one Vector<OffsetLocation>

    77         Vector<int32_t> branchOffsets;

    78         int32_t min;

    79 #if ENABLE(JIT)

    80         Vector<CodeLocationLabel> ctiOffsets;

    81         CodeLocationLabel ctiDefault;

    82 #endif

    83 

    84         int32_t offsetForValue(int32_t value, int32_t defaultOffset);

    85         void add(int32_t key, int32_t offset)

    86         {

    87             if (!branchOffsets[key])

    88                 branchOffsets[key] = offset;

    89         }

    90 

    91 #if ENABLE(JIT)

    92         inline CodeLocationLabel ctiForValue(int32_t value)

    93         {

    94             if (value >= min && static_cast<uint32_t>(value - min) < ctiOffsets.size())

    95                 return ctiOffsets[value - min];

    96             return ctiDefault;

    97         }

    98 #endif

    99     };

   100 

   101 } // namespace JSC

   102 

   103 #endif // JumpTable_h