aoqi@0: /*
aoqi@0:  * Copyright (c) 1998, 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #ifndef SHARE_VM_CODE_EXCEPTIONHANDLERTABLE_HPP
aoqi@0: #define SHARE_VM_CODE_EXCEPTIONHANDLERTABLE_HPP
aoqi@0: 
aoqi@0: #include "memory/allocation.hpp"
aoqi@0: #include "oops/method.hpp"
aoqi@0: 
aoqi@0: // A HandlerTableEntry describes an individual entry of a subtable
aoqi@0: // of ExceptionHandlerTable. An entry consists of a pair(bci, pco),
aoqi@0: // where bci is the exception handler bci, and pco is the pc offset
aoqi@0: // relative to the nmethod code start for the compiled exception
aoqi@0: // handler corresponding to the (interpreted) exception handler
aoqi@0: // starting at bci.
aoqi@0: //
aoqi@0: // The first HandlerTableEntry of each subtable holds the length
aoqi@0: // and catch_pco for the subtable (the length is the number of
aoqi@0: // subtable entries w/o header).
aoqi@0: 
aoqi@0: class HandlerTableEntry {
aoqi@0:  private:
aoqi@0:   int _bci;
aoqi@0:   int _pco;
aoqi@0:   int _scope_depth;
aoqi@0: 
aoqi@0:  public:
aoqi@0:   HandlerTableEntry(int bci, int pco, int scope_depth) {
aoqi@0:     assert( 0 <= pco, "pco must be positive");
aoqi@0:     assert( 0 <= scope_depth, "scope_depth must be positive");
aoqi@0:     _bci = bci;
aoqi@0:     _pco = pco;
aoqi@0:     _scope_depth = scope_depth;
aoqi@0:   }
aoqi@0: 
aoqi@0:   int len() const { return _bci; } // for entry at subtable begin
aoqi@0:   int bci() const { return _bci; }
aoqi@0:   int pco() const { return _pco; }
aoqi@0:   int scope_depth() const { return _scope_depth; }
aoqi@0: };
aoqi@0: 
aoqi@0: 
aoqi@0: // An ExceptionHandlerTable is an abstraction over a list of subtables
aoqi@0: // of exception handlers for CatchNodes. Each subtable has a one-entry
aoqi@0: // header holding length and catch_pco of the subtable, followed
aoqi@0: // by 'length' entries for each exception handler that can be reached
aoqi@0: // from the corresponding CatchNode. The catch_pco is the pc offset of
aoqi@0: // the CatchNode in the corresponding nmethod. Empty subtables are dis-
aoqi@0: // carded.
aoqi@0: //
aoqi@0: // Structure of the table:
aoqi@0: //
aoqi@0: // table    = { subtable }.
aoqi@0: // subtable = header entry { entry }.
aoqi@0: // header   = a pair (number of subtable entries, catch pc offset, [unused])
aoqi@0: // entry    = a pair (handler bci, handler pc offset, scope depth)
aoqi@0: //
aoqi@0: // An ExceptionHandlerTable can be created from scratch, in which case
aoqi@0: // it is possible to add subtables. It can also be created from an
aoqi@0: // nmethod (for lookup purposes) in which case the table cannot be
aoqi@0: // modified.
aoqi@0: 
aoqi@0: class nmethod;
aoqi@0: class ExceptionHandlerTable VALUE_OBJ_CLASS_SPEC {
aoqi@0:  private:
aoqi@0:   HandlerTableEntry* _table;    // the table
aoqi@0:   int                _length;   // the current length of the table
aoqi@0:   int                _size;     // the number of allocated entries
aoqi@0:   ReallocMark        _nesting;  // assertion check for reallocations
aoqi@0: 
aoqi@0:   // add the entry & grow the table if needed
aoqi@0:   void add_entry(HandlerTableEntry entry);
aoqi@0:   HandlerTableEntry* subtable_for(int catch_pco) const;
aoqi@0: 
aoqi@0:  public:
aoqi@0:   // (compile-time) construction within compiler
aoqi@0:   ExceptionHandlerTable(int initial_size = 8);
aoqi@0: 
aoqi@0:   // (run-time) construction from nmethod
aoqi@0:   ExceptionHandlerTable(const nmethod* nm);
aoqi@0: 
aoqi@0:   // (compile-time) add entries
aoqi@0:   void add_subtable(
aoqi@0:     int                 catch_pco, // the pc offset for the CatchNode
aoqi@0:     GrowableArray<intptr_t>* handler_bcis, // the exception handler entry point bcis
aoqi@0:     GrowableArray<intptr_t>* scope_depths_from_top_scope,
aoqi@0:                                            // if representing exception handlers in multiple
aoqi@0:                                            // inlined scopes, indicates which scope relative to
aoqi@0:                                            // the youngest/innermost one in which we are performing
aoqi@0:                                            // the lookup; zero (or null GrowableArray) indicates
aoqi@0:                                            // innermost scope
aoqi@0:     GrowableArray<intptr_t>* handler_pcos  // pc offsets for the compiled handlers
aoqi@0:   );
aoqi@0: 
aoqi@0:   // nmethod support
aoqi@0:   int  size_in_bytes() const { return round_to(_length * sizeof(HandlerTableEntry), oopSize); }
aoqi@0:   void copy_to(nmethod* nm);
aoqi@0: 
aoqi@0:   // lookup
aoqi@0:   HandlerTableEntry* entry_for(int catch_pco, int handler_bci, int scope_depth) const;
aoqi@0: 
aoqi@0:   // debugging
aoqi@0:   void print_subtable(HandlerTableEntry* t) const;
aoqi@0:   void print() const;
aoqi@0:   void print_subtable_for(int catch_pco) const;
aoqi@0: };
aoqi@0: 
aoqi@0: 
aoqi@0: // ----------------------------------------------------------------------------
aoqi@0: // Implicit null exception tables.  Maps an exception PC offset to a
aoqi@0: // continuation PC offset.  During construction it's a variable sized
aoqi@0: // array with a max size and current length.  When stored inside an
aoqi@0: // nmethod a zero length table takes no space.  This is detected by
aoqi@0: // nul_chk_table_size() == 0.  Otherwise the table has a length word
aoqi@0: // followed by pairs of <excp-offset, const-offset>.
aoqi@0: 
aoqi@0: // Use 32-bit representation for offsets
aoqi@0: typedef  uint              implicit_null_entry;
aoqi@0: 
aoqi@0: class ImplicitExceptionTable VALUE_OBJ_CLASS_SPEC {
aoqi@0:   uint _size;
aoqi@0:   uint _len;
aoqi@0:   implicit_null_entry *_data;
aoqi@0:   implicit_null_entry *adr( uint idx ) const { return &_data[2*idx]; }
aoqi@0:   ReallocMark          _nesting;  // assertion check for reallocations
aoqi@0: public:
aoqi@0:   ImplicitExceptionTable( ) :  _data(0), _size(0), _len(0) { }
aoqi@0:   // (run-time) construction from nmethod
aoqi@0:   ImplicitExceptionTable( const nmethod *nm );
aoqi@0: 
aoqi@0:   void set_size( uint size );
aoqi@0:   void append( uint exec_off, uint cont_off );
aoqi@0:   uint at( uint exec_off ) const;
aoqi@0: 
aoqi@0:   uint len() const { return _len; }
aoqi@0:   int size_in_bytes() const { return len() == 0 ? 0 : ((2 * len() + 1) * sizeof(implicit_null_entry)); }
aoqi@0: 
aoqi@0:   void copy_to(nmethod* nm);
aoqi@0:   void print(address base) const;
aoqi@0:   void verify(nmethod *nm) const;
aoqi@0: };
aoqi@0: 
aoqi@0: #endif // SHARE_VM_CODE_EXCEPTIONHANDLERTABLE_HPP