1 /*

     2  * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #ifndef SHARE_VM_CLASSFILE_BYTECODEASSEMBLER_HPP

    26 #define SHARE_VM_CLASSFILE_BYTECODEASSEMBLER_HPP

    27 

    28 #include "memory/allocation.hpp"

    29 #include "oops/method.hpp"

    30 #include "oops/symbol.hpp"

    31 #include "utilities/globalDefinitions.hpp"

    32 #include "utilities/growableArray.hpp"

    33 #include "utilities/resourceHash.hpp"

    34 

    35 

    36 /**

    37  * Bytecode Assembler

    38  *

    39  * These classes are used to synthesize code for creating new methods from

    40  * within the VM.  This is only a partial implementation of an assembler;

    41  * only the bytecodes that are needed by clients are implemented at this time.

    42  * This is used during default method analysis to create overpass methods

    43  * and add them to a call during parsing.  Other uses (such as creating

    44  * bridges) may come later.  Any missing bytecodes can be implemented on an

    45  * as-need basis.

    46  */

    47 

    48 class BytecodeBuffer : public GrowableArray<u1> {

    49  public:

    50   BytecodeBuffer() : GrowableArray<u1>(20) {}

    51 };

    52 

    53 // Entries in a yet-to-be-created constant pool.  Limited types for now.

    54 class BytecodeCPEntry VALUE_OBJ_CLASS_SPEC {

    55  public:

    56   enum tag {

    57     ERROR_TAG,

    58     UTF8,

    59     KLASS,

    60     STRING,

    61     NAME_AND_TYPE,

    62     METHODREF

    63   };

    64 

    65   u1 _tag;

    66   union {

    67     Symbol* utf8;

    68     u2 klass;

    69     u2 string;

    70     struct {

    71       u2 name_index;

    72       u2 type_index;

    73     } name_and_type;

    74     struct {

    75       u2 class_index;

    76       u2 name_and_type_index;

    77     } methodref;

    78     uintptr_t hash;

    79   } _u;

    80 

    81   BytecodeCPEntry() : _tag(ERROR_TAG) { _u.hash = 0; }

    82   BytecodeCPEntry(u1 tag) : _tag(tag) { _u.hash = 0; }

    83 

    84   static BytecodeCPEntry utf8(Symbol* symbol) {

    85     BytecodeCPEntry bcpe(UTF8);

    86     bcpe._u.utf8 = symbol;

    87     return bcpe;

    88   }

    89 

    90   static BytecodeCPEntry klass(u2 index) {

    91     BytecodeCPEntry bcpe(KLASS);

    92     bcpe._u.klass = index;

    93     return bcpe;

    94   }

    95 

    96   static BytecodeCPEntry string(u2 index) {

    97     BytecodeCPEntry bcpe(STRING);

    98     bcpe._u.string = index;

    99     return bcpe;

   100   }

   101 

   102   static BytecodeCPEntry name_and_type(u2 name, u2 type) {

   103     BytecodeCPEntry bcpe(NAME_AND_TYPE);

   104     bcpe._u.name_and_type.name_index = name;

   105     bcpe._u.name_and_type.type_index = type;

   106     return bcpe;

   107   }

   108 

   109   static BytecodeCPEntry methodref(u2 class_index, u2 nat) {

   110     BytecodeCPEntry bcpe(METHODREF);

   111     bcpe._u.methodref.class_index = class_index;

   112     bcpe._u.methodref.name_and_type_index = nat;

   113     return bcpe;

   114   }

   115 

   116   static bool equals(BytecodeCPEntry const& e0, BytecodeCPEntry const& e1) {

   117     return e0._tag == e1._tag && e0._u.hash == e1._u.hash;

   118   }

   119 

   120   static unsigned hash(BytecodeCPEntry const& e0) {

   121     return (unsigned)(e0._tag ^ e0._u.hash);

   122   }

   123 };

   124 

   125 class BytecodeConstantPool : ResourceObj {

   126  private:

   127   typedef ResourceHashtable<BytecodeCPEntry, u2,

   128       &BytecodeCPEntry::hash, &BytecodeCPEntry::equals> IndexHash;

   129 

   130   ConstantPool* _orig;

   131   GrowableArray<BytecodeCPEntry> _entries;

   132   IndexHash _indices;

   133 

   134   u2 find_or_add(BytecodeCPEntry const& bcpe);

   135 

   136  public:

   137 

   138   BytecodeConstantPool(ConstantPool* orig) : _orig(orig) {}

   139 

   140   BytecodeCPEntry const& at(u2 index) const { return _entries.at(index); }

   141 

   142   InstanceKlass* pool_holder() const {

   143     return InstanceKlass::cast(_orig->pool_holder());

   144   }

   145 

   146   u2 utf8(Symbol* sym) {

   147     return find_or_add(BytecodeCPEntry::utf8(sym));

   148   }

   149 

   150   u2 klass(Symbol* class_name) {

   151     return find_or_add(BytecodeCPEntry::klass(utf8(class_name)));

   152   }

   153 

   154   u2 string(Symbol* str) {

   155     return find_or_add(BytecodeCPEntry::string(utf8(str)));

   156   }

   157 

   158   u2 name_and_type(Symbol* name, Symbol* sig) {

   159     return find_or_add(BytecodeCPEntry::name_and_type(utf8(name), utf8(sig)));

   160   }

   161 

   162   u2 methodref(Symbol* class_name, Symbol* name, Symbol* sig) {

   163     return find_or_add(BytecodeCPEntry::methodref(

   164         klass(class_name), name_and_type(name, sig)));

   165   }

   166 

   167   ConstantPool* create_constant_pool(TRAPS) const;

   168 };

   169 

   170 // Partial bytecode assembler - only what we need for creating

   171 // overpass methods for default methods is implemented

   172 class BytecodeAssembler : StackObj {

   173  private:

   174   BytecodeBuffer* _code;

   175   BytecodeConstantPool* _cp;

   176 

   177   void append(u1 imm_u1);

   178   void append(u2 imm_u2);

   179   void append(u4 imm_u4);

   180 

   181   void xload(u4 index, u1 quick, u1 twobyte);

   182 

   183  public:

   184   BytecodeAssembler(BytecodeBuffer* buffer, BytecodeConstantPool* cp)

   185     : _code(buffer), _cp(cp) {}

   186 

   187   void aload(u4 index);

   188   void areturn();

   189   void athrow();

   190   void checkcast(Symbol* sym);

   191   void dload(u4 index);

   192   void dreturn();

   193   void dup();

   194   void fload(u4 index);

   195   void freturn();

   196   void iload(u4 index);

   197   void invokespecial(Method* method);

   198   void invokespecial(Symbol* cls, Symbol* name, Symbol* sig);

   199   void invokevirtual(Method* method);

   200   void invokevirtual(Symbol* cls, Symbol* name, Symbol* sig);

   201   void ireturn();

   202   void ldc(u1 index);

   203   void ldc_w(u2 index);

   204   void lload(u4 index);

   205   void lreturn();

   206   void _new(Symbol* sym);

   207   void _return();

   208 

   209   void load_string(Symbol* sym);

   210   void load(BasicType bt, u4 index);

   211   void _return(BasicType bt);

   212 };

   213 

   214 #endif // SHARE_VM_CLASSFILE_BYTECODEASSEMBLER_HPP