1 /*

     2  * Copyright (c) 1999, 2016, 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_CI_CISTREAMS_HPP

    26 #define SHARE_VM_CI_CISTREAMS_HPP

    27 

    28 #include "ci/ciClassList.hpp"

    29 #include "ci/ciExceptionHandler.hpp"

    30 #include "ci/ciInstanceKlass.hpp"

    31 #include "ci/ciMethod.hpp"

    32 #include "interpreter/bytecode.hpp"

    33 

    34 // ciBytecodeStream

    35 //

    36 // The class is used to iterate over the bytecodes of a method.

    37 // It hides the details of constant pool structure/access by

    38 // providing accessors for constant pool items.  It returns only pure

    39 // Java bytecodes; VM-internal _fast bytecodes are translated back to

    40 // their original form during iteration.

    41 class ciBytecodeStream : StackObj {

    42 private:

    43   // Handling for the weird bytecodes

    44   Bytecodes::Code next_wide_or_table(Bytecodes::Code); // Handle _wide & complicated inline table

    45 

    46   static Bytecodes::Code check_java(Bytecodes::Code c) {

    47     assert(Bytecodes::is_java_code(c), "should not return _fast bytecodes");

    48     return c;

    49   }

    50 

    51   static Bytecodes::Code check_defined(Bytecodes::Code c) {

    52     assert(Bytecodes::is_defined(c), "");

    53     return c;

    54   }

    55 

    56   ciMethod* _method;           // the method

    57   ciInstanceKlass* _holder;

    58   address _bc_start;            // Start of current bytecode for table

    59   address _was_wide;            // Address past last wide bytecode

    60   jint* _table_base;            // Aligned start of last table or switch

    61 

    62   address _start;                  // Start of bytecodes

    63   address _end;                    // Past end of bytecodes

    64   address _pc;                     // Current PC

    65   Bytecodes::Code _bc;             // Current bytecode

    66   Bytecodes::Code _raw_bc;         // Current bytecode, raw form

    67 

    68   void reset( address base, unsigned int size ) {

    69     _bc_start =_was_wide = 0;

    70     _start = _pc = base; _end = base + size;

    71   }

    72 

    73   void assert_wide(bool require_wide) const {

    74     if (require_wide)

    75          { assert(is_wide(),  "must be a wide instruction"); }

    76     else { assert(!is_wide(), "must not be a wide instruction"); }

    77   }

    78 

    79   Bytecode bytecode() const { return Bytecode(this, _bc_start); }

    80   Bytecode next_bytecode() const { return Bytecode(this, _pc); }

    81 

    82 public:

    83   // End-Of-Bytecodes

    84   static Bytecodes::Code EOBC() {

    85     return Bytecodes::_illegal;

    86   }

    87 

    88   ciBytecodeStream(ciMethod* m) {

    89     reset_to_method(m);

    90   }

    91 

    92   ciBytecodeStream() {

    93     reset_to_method(NULL);

    94   }

    95 

    96   ciMethod* method() const { return _method; }

    97 

    98   void reset_to_method(ciMethod* m) {

    99     _method = m;

   100     if (m == NULL) {

   101       _holder = NULL;

   102       reset(NULL, 0);

   103     } else {

   104       _holder = m->holder();

   105       reset(m->code(), m->code_size());

   106     }

   107   }

   108 

   109   void reset_to_bci( int bci );

   110 

   111   // Force the iterator to report a certain bci.

   112   void force_bci(int bci);

   113 

   114   void set_max_bci( int max ) {

   115     _end = _start + max;

   116   }

   117 

   118   address cur_bcp() const       { return _bc_start; }  // Returns bcp to current instruction

   119   int next_bci() const          { return _pc - _start; }

   120   int cur_bci() const           { return _bc_start - _start; }

   121   int instruction_size() const  { return _pc - _bc_start; }

   122 

   123   Bytecodes::Code cur_bc() const{ return check_java(_bc); }

   124   Bytecodes::Code cur_bc_raw() const { return check_defined(_raw_bc); }

   125   Bytecodes::Code next_bc()     { return Bytecodes::java_code((Bytecodes::Code)* _pc); }

   126 

   127   // Return current ByteCode and increment PC to next bytecode, skipping all

   128   // intermediate constants.  Returns EOBC at end.

   129   // Expected usage:

   130   //     ciBytecodeStream iter(m);

   131   //     while (iter.next() != ciBytecodeStream::EOBC()) { ... }

   132   Bytecodes::Code next() {

   133     _bc_start = _pc;                        // Capture start of bc

   134     if( _pc >= _end ) return EOBC();        // End-Of-Bytecodes

   135 

   136     // Fetch Java bytecode

   137     // All rewritten bytecodes maintain the size of original bytecode.

   138     _bc = Bytecodes::java_code(_raw_bc = (Bytecodes::Code)*_pc);

   139     int csize = Bytecodes::length_for(_bc); // Expected size

   140     _pc += csize;                           // Bump PC past bytecode

   141     if (csize == 0) {

   142       _bc = next_wide_or_table(_bc);

   143     }

   144     return check_java(_bc);

   145   }

   146 

   147   bool is_wide() const { return ( _pc == _was_wide ); }

   148 

   149   // Does this instruction contain an index which refes into the CP cache?

   150   bool has_cache_index() const { return Bytecodes::uses_cp_cache(cur_bc_raw()); }

   151 

   152   bool has_optional_appendix() { return Bytecodes::has_optional_appendix(cur_bc_raw()); }

   153 

   154   int get_index_u1() const {

   155     return bytecode().get_index_u1(cur_bc_raw());

   156   }

   157 

   158   int get_index_u1_cpcache() const {

   159     return bytecode().get_index_u1_cpcache(cur_bc_raw());

   160   }

   161 

   162   // Get a byte index following this bytecode.

   163   // If prefixed with a wide bytecode, get a wide index.

   164   int get_index() const {

   165     assert(!has_cache_index(), "else use cpcache variant");

   166     return (_pc == _was_wide)   // was widened?

   167       ? get_index_u2(true)      // yes, return wide index

   168       : get_index_u1();         // no, return narrow index

   169   }

   170 

   171   // Get 2-byte index (byte swapping depending on which bytecode)

   172   int get_index_u2(bool is_wide = false) const {

   173     return bytecode().get_index_u2(cur_bc_raw(), is_wide);

   174   }

   175 

   176   // Get 2-byte index in native byte order.  (Rewriter::rewrite makes these.)

   177   int get_index_u2_cpcache() const {

   178     return bytecode().get_index_u2_cpcache(cur_bc_raw());

   179   }

   180 

   181   // Get 4-byte index, for invokedynamic.

   182   int get_index_u4() const {

   183     return bytecode().get_index_u4(cur_bc_raw());

   184   }

   185 

   186   bool has_index_u4() const {

   187     return bytecode().has_index_u4(cur_bc_raw());

   188   }

   189 

   190   // Get dimensions byte (multinewarray)

   191   int get_dimensions() const { return *(unsigned char*)(_pc-1); }

   192 

   193   // Sign-extended index byte/short, no widening

   194   int get_constant_u1()                     const { return bytecode().get_constant_u1(instruction_size()-1, cur_bc_raw()); }

   195   int get_constant_u2(bool is_wide = false) const { return bytecode().get_constant_u2(instruction_size()-2, cur_bc_raw(), is_wide); }

   196 

   197   // Get a byte signed constant for "iinc".  Invalid for other bytecodes.

   198   // If prefixed with a wide bytecode, get a wide constant

   199   int get_iinc_con() const {return (_pc==_was_wide) ? (jshort) get_constant_u2(true) : (jbyte) get_constant_u1();}

   200 

   201   // 2-byte branch offset from current pc

   202   int get_dest() const {

   203     return cur_bci() + bytecode().get_offset_s2(cur_bc_raw());

   204   }

   205 

   206   // 2-byte branch offset from next pc

   207   int next_get_dest() const {

   208     assert(_pc < _end, "");

   209     return next_bci() + next_bytecode().get_offset_s2(Bytecodes::_ifeq);

   210   }

   211 

   212   // 4-byte branch offset from current pc

   213   int get_far_dest() const {

   214     return cur_bci() + bytecode().get_offset_s4(cur_bc_raw());

   215   }

   216 

   217   // For a lookup or switch table, return target destination

   218   int get_int_table( int index ) const {

   219     return Bytes::get_Java_u4((address)&_table_base[index]); }

   220 

   221   // For tableswitch - get length of offset part

   222   int get_tableswitch_length()  { return get_int_table(2)-get_int_table(1)+1; }

   223 

   224   int get_dest_table( int index ) const {

   225     return cur_bci() + get_int_table(index); }

   226 

   227   // --- Constant pool access ---

   228   int get_constant_raw_index() const;

   229   int get_constant_pool_index() const;

   230   int get_constant_cache_index() const;

   231   int get_field_index();

   232   int get_method_index();

   233 

   234   // If this bytecode is a new, newarray, multianewarray, instanceof,

   235   // or checkcast, get the referenced klass.

   236   ciKlass* get_klass(bool& will_link);

   237   int get_klass_index() const;

   238 

   239   // If this bytecode is one of the ldc variants, get the referenced

   240   // constant.  Do not attempt to resolve it, since that would require

   241   // execution of Java code.  If it is not resolved, return an unloaded

   242   // object (ciConstant.as_object()->is_loaded() == false).

   243   ciConstant get_constant();

   244   constantTag get_constant_pool_tag(int index) const;

   245 

   246   // True if the klass-using bytecode points to an unresolved klass

   247   bool is_unresolved_klass() const {

   248     constantTag tag = get_constant_pool_tag(get_klass_index());

   249     return tag.is_unresolved_klass();

   250   }

   251 

   252   // If this bytecode is one of get_field, get_static, put_field,

   253   // or put_static, get the referenced field.

   254   ciField* get_field(bool& will_link);

   255 

   256   ciInstanceKlass* get_declared_field_holder();

   257   int      get_field_holder_index();

   258   int      get_field_signature_index();

   259 

   260   ciMethod*     get_method(bool& will_link, ciSignature* *declared_signature_result);

   261   bool          has_appendix();

   262   ciObject*     get_appendix();

   263   bool          has_method_type();

   264   ciMethodType* get_method_type();

   265   ciKlass*      get_declared_method_holder();

   266   int           get_method_holder_index();

   267   int           get_method_signature_index(const constantPoolHandle& cpool);

   268 

   269   // Get the resolved references arrays from the constant pool

   270   ciObjArray* get_resolved_references();

   271 };

   272 

   273 

   274 // ciSignatureStream

   275 //

   276 // The class is used to iterate over the elements of a method signature.

   277 class ciSignatureStream : public StackObj {

   278 private:

   279   ciSignature* _sig;

   280   int          _pos;

   281   // holder is a method's holder

   282   ciKlass*     _holder;

   283 public:

   284   ciSignatureStream(ciSignature* signature, ciKlass* holder = NULL) {

   285     _sig = signature;

   286     _pos = 0;

   287     _holder = holder;

   288   }

   289 

   290   bool at_return_type() { return _pos == _sig->count(); }

   291 

   292   bool is_done() { return _pos > _sig->count(); }

   293 

   294   void next() {

   295     if (_pos <= _sig->count()) {

   296       _pos++;

   297     }

   298   }

   299 

   300   ciType* type() {

   301     if (at_return_type()) {

   302       return _sig->return_type();

   303     } else {

   304       return _sig->type_at(_pos);

   305     }

   306   }

   307 

   308   // next klass in the signature

   309   ciKlass* next_klass() {

   310     ciKlass* sig_k;

   311     if (_holder != NULL) {

   312       sig_k = _holder;

   313       _holder = NULL;

   314     } else {

   315       while (!type()->is_klass()) {

   316         next();

   317       }

   318       assert(!at_return_type(), "passed end of signature");

   319       sig_k = type()->as_klass();

   320       next();

   321     }

   322     return sig_k;

   323   }

   324 };

   325 

   326 

   327 // ciExceptionHandlerStream

   328 //

   329 // The class is used to iterate over the exception handlers of

   330 // a method.

   331 class ciExceptionHandlerStream : public StackObj {

   332 private:

   333   // The method whose handlers we are traversing

   334   ciMethod* _method;

   335 

   336   // Our current position in the list of handlers

   337   int        _pos;

   338   int        _end;

   339 

   340   ciInstanceKlass*  _exception_klass;

   341   int        _bci;

   342   bool       _is_exact;

   343 

   344 public:

   345   ciExceptionHandlerStream(ciMethod* method) {

   346     _method = method;

   347 

   348     // Force loading of method code and handlers.

   349     _method->code();

   350 

   351     _pos = 0;

   352     _end = _method->_handler_count;

   353     _exception_klass = NULL;

   354     _bci    = -1;

   355     _is_exact = false;

   356   }

   357 

   358   ciExceptionHandlerStream(ciMethod* method, int bci,

   359                            ciInstanceKlass* exception_klass = NULL,

   360                            bool is_exact = false) {

   361     _method = method;

   362 

   363     // Force loading of method code and handlers.

   364     _method->code();

   365 

   366     _pos = -1;

   367     _end = _method->_handler_count + 1; // include the rethrow handler

   368     _exception_klass = (exception_klass != NULL && exception_klass->is_loaded()

   369                           ? exception_klass

   370                           : NULL);

   371     _bci = bci;

   372     assert(_bci >= 0, "bci out of range");

   373     _is_exact = is_exact;

   374     next();

   375   }

   376 

   377   // These methods are currently implemented in an odd way.

   378   // Count the number of handlers the iterator has ever produced

   379   // or will ever produce.  Do not include the final rethrow handler.

   380   // That is, a trivial exception handler stream will have a count

   381   // of zero and produce just the rethrow handler.

   382   int count();

   383 

   384   // Count the number of handlers this stream will produce from now on.

   385   // Include the current handler, and the final rethrow handler.

   386   // The remaining count will be zero iff is_done() is true,

   387   int count_remaining();

   388 

   389   bool is_done() {

   390     return (_pos >= _end);

   391   }

   392 

   393   void next() {

   394     _pos++;

   395     if (_bci != -1) {

   396       // We are not iterating over all handlers...

   397       while (!is_done()) {

   398         ciExceptionHandler* handler = _method->_exception_handlers[_pos];

   399         if (handler->is_in_range(_bci)) {

   400           if (handler->is_catch_all()) {

   401             // Found final active catch block.

   402             _end = _pos+1;

   403             return;

   404           } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) {

   405             // We cannot do any type analysis here.  Must conservatively assume

   406             // catch block is reachable.

   407             return;

   408           } else if (_exception_klass->is_subtype_of(handler->catch_klass())) {

   409             // This catch clause will definitely catch the exception.

   410             // Final candidate.

   411             _end = _pos+1;

   412             return;

   413           } else if (!_is_exact &&

   414                      handler->catch_klass()->is_subtype_of(_exception_klass)) {

   415             // This catch block may be reachable.

   416             return;

   417           }

   418         }

   419 

   420         // The catch block was not pertinent.  Go on.

   421         _pos++;

   422       }

   423     } else {

   424       // This is an iteration over all handlers.

   425       return;

   426     }

   427   }

   428 

   429   ciExceptionHandler* handler() {

   430     return _method->_exception_handlers[_pos];

   431   }

   432 };

   433 

   434 

   435 

   436 // Implementation for declarations in bytecode.hpp

   437 Bytecode::Bytecode(const ciBytecodeStream* stream, address bcp): _bcp(bcp != NULL ? bcp : stream->cur_bcp()), _code(Bytecodes::code_at(NULL, addr_at(0))) {}

   438 Bytecode_lookupswitch::Bytecode_lookupswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); }

   439 Bytecode_tableswitch::Bytecode_tableswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); }

   440 

   441 #endif // SHARE_VM_CI_CISTREAMS_HPP