duke@435: /*
coleenp@4037:  * Copyright (c) 1998, 2012, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #ifndef SHARE_VM_CODE_EXCEPTIONHANDLERTABLE_HPP
stefank@2314: #define SHARE_VM_CODE_EXCEPTIONHANDLERTABLE_HPP
stefank@2314: 
stefank@2314: #include "memory/allocation.hpp"
coleenp@4037: #include "oops/method.hpp"
stefank@2314: 
duke@435: // A HandlerTableEntry describes an individual entry of a subtable
duke@435: // of ExceptionHandlerTable. An entry consists of a pair(bci, pco),
duke@435: // where bci is the exception handler bci, and pco is the pc offset
duke@435: // relative to the nmethod code start for the compiled exception
duke@435: // handler corresponding to the (interpreted) exception handler
duke@435: // starting at bci.
duke@435: //
duke@435: // The first HandlerTableEntry of each subtable holds the length
duke@435: // and catch_pco for the subtable (the length is the number of
duke@435: // subtable entries w/o header).
duke@435: 
duke@435: class HandlerTableEntry {
duke@435:  private:
duke@435:   int _bci;
duke@435:   int _pco;
duke@435:   int _scope_depth;
duke@435: 
duke@435:  public:
duke@435:   HandlerTableEntry(int bci, int pco, int scope_depth) {
duke@435:     assert( 0 <= pco, "pco must be positive");
duke@435:     assert( 0 <= scope_depth, "scope_depth must be positive");
duke@435:     _bci = bci;
duke@435:     _pco = pco;
duke@435:     _scope_depth = scope_depth;
duke@435:   }
duke@435: 
duke@435:   int len() const { return _bci; } // for entry at subtable begin
duke@435:   int bci() const { return _bci; }
duke@435:   int pco() const { return _pco; }
duke@435:   int scope_depth() const { return _scope_depth; }
duke@435: };
duke@435: 
duke@435: 
duke@435: // An ExceptionHandlerTable is an abstraction over a list of subtables
duke@435: // of exception handlers for CatchNodes. Each subtable has a one-entry
duke@435: // header holding length and catch_pco of the subtable, followed
duke@435: // by 'length' entries for each exception handler that can be reached
duke@435: // from the corresponding CatchNode. The catch_pco is the pc offset of
duke@435: // the CatchNode in the corresponding nmethod. Empty subtables are dis-
duke@435: // carded.
duke@435: //
duke@435: // Structure of the table:
duke@435: //
duke@435: // table    = { subtable }.
duke@435: // subtable = header entry { entry }.
duke@435: // header   = a pair (number of subtable entries, catch pc offset, [unused])
duke@435: // entry    = a pair (handler bci, handler pc offset, scope depth)
duke@435: //
duke@435: // An ExceptionHandlerTable can be created from scratch, in which case
duke@435: // it is possible to add subtables. It can also be created from an
duke@435: // nmethod (for lookup purposes) in which case the table cannot be
duke@435: // modified.
duke@435: 
duke@435: class nmethod;
duke@435: class ExceptionHandlerTable VALUE_OBJ_CLASS_SPEC {
duke@435:  private:
duke@435:   HandlerTableEntry* _table;    // the table
duke@435:   int                _length;   // the current length of the table
duke@435:   int                _size;     // the number of allocated entries
duke@435:   ReallocMark        _nesting;  // assertion check for reallocations
duke@435: 
duke@435:   // add the entry & grow the table if needed
duke@435:   void add_entry(HandlerTableEntry entry);
duke@435:   HandlerTableEntry* subtable_for(int catch_pco) const;
duke@435: 
duke@435:  public:
duke@435:   // (compile-time) construction within compiler
duke@435:   ExceptionHandlerTable(int initial_size = 8);
duke@435: 
duke@435:   // (run-time) construction from nmethod
duke@435:   ExceptionHandlerTable(const nmethod* nm);
duke@435: 
duke@435:   // (compile-time) add entries
duke@435:   void add_subtable(
duke@435:     int                 catch_pco, // the pc offset for the CatchNode
duke@435:     GrowableArray<intptr_t>* handler_bcis, // the exception handler entry point bcis
duke@435:     GrowableArray<intptr_t>* scope_depths_from_top_scope,
duke@435:                                            // if representing exception handlers in multiple
duke@435:                                            // inlined scopes, indicates which scope relative to
duke@435:                                            // the youngest/innermost one in which we are performing
duke@435:                                            // the lookup; zero (or null GrowableArray) indicates
duke@435:                                            // innermost scope
duke@435:     GrowableArray<intptr_t>* handler_pcos  // pc offsets for the compiled handlers
duke@435:   );
duke@435: 
duke@435:   // nmethod support
duke@435:   int  size_in_bytes() const { return round_to(_length * sizeof(HandlerTableEntry), oopSize); }
duke@435:   void copy_to(nmethod* nm);
duke@435: 
duke@435:   // lookup
duke@435:   HandlerTableEntry* entry_for(int catch_pco, int handler_bci, int scope_depth) const;
duke@435: 
duke@435:   // debugging
duke@435:   void print_subtable(HandlerTableEntry* t) const;
duke@435:   void print() const;
duke@435:   void print_subtable_for(int catch_pco) const;
duke@435: };
duke@435: 
duke@435: 
duke@435: // ----------------------------------------------------------------------------
duke@435: // Implicit null exception tables.  Maps an exception PC offset to a
duke@435: // continuation PC offset.  During construction it's a variable sized
duke@435: // array with a max size and current length.  When stored inside an
duke@435: // nmethod a zero length table takes no space.  This is detected by
duke@435: // nul_chk_table_size() == 0.  Otherwise the table has a length word
duke@435: // followed by pairs of <excp-offset, const-offset>.
duke@435: 
duke@435: // Use 32-bit representation for offsets
duke@435: typedef  uint              implicit_null_entry;
duke@435: 
duke@435: class ImplicitExceptionTable VALUE_OBJ_CLASS_SPEC {
duke@435:   uint _size;
duke@435:   uint _len;
duke@435:   implicit_null_entry *_data;
duke@435:   implicit_null_entry *adr( uint idx ) const { return &_data[2*idx]; }
duke@435:   ReallocMark          _nesting;  // assertion check for reallocations
duke@435: public:
duke@435:   ImplicitExceptionTable( ) :  _data(0), _size(0), _len(0) { }
duke@435:   // (run-time) construction from nmethod
duke@435:   ImplicitExceptionTable( const nmethod *nm );
duke@435: 
duke@435:   void set_size( uint size );
duke@435:   void append( uint exec_off, uint cont_off );
duke@435:   uint at( uint exec_off ) const;
duke@435: 
duke@435:   uint len() const { return _len; }
duke@435:   int size_in_bytes() const { return len() == 0 ? 0 : ((2 * len() + 1) * sizeof(implicit_null_entry)); }
duke@435: 
duke@435:   void copy_to(nmethod* nm);
duke@435:   void print(address base) const;
duke@435:   void verify(nmethod *nm) const;
duke@435: };
stefank@2314: 
stefank@2314: #endif // SHARE_VM_CODE_EXCEPTIONHANDLERTABLE_HPP