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comparison: src/share/vm/code/exceptionHandlerTable.hpp
src/share/vm/code/exceptionHandlerTable.hpp
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| 1 /* | |
| 2 * Copyright (c) 1998, 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_CODE_EXCEPTIONHANDLERTABLE_HPP | |
| 26 #define SHARE_VM_CODE_EXCEPTIONHANDLERTABLE_HPP | |
| 27 | |
| 28 #include "memory/allocation.hpp" | |
| 29 #include "oops/method.hpp" | |
| 30 | |
| 31 // A HandlerTableEntry describes an individual entry of a subtable | |
| 32 // of ExceptionHandlerTable. An entry consists of a pair(bci, pco), | |
| 33 // where bci is the exception handler bci, and pco is the pc offset | |
| 34 // relative to the nmethod code start for the compiled exception | |
| 35 // handler corresponding to the (interpreted) exception handler | |
| 36 // starting at bci. | |
| 37 // | |
| 38 // The first HandlerTableEntry of each subtable holds the length | |
| 39 // and catch_pco for the subtable (the length is the number of | |
| 40 // subtable entries w/o header). | |
| 41 | |
| 42 class HandlerTableEntry { | |
| 43 private: | |
| 44 int _bci; | |
| 45 int _pco; | |
| 46 int _scope_depth; | |
| 47 | |
| 48 public: | |
| 49 HandlerTableEntry(int bci, int pco, int scope_depth) { | |
| 50 assert( 0 <= pco, "pco must be positive"); | |
| 51 assert( 0 <= scope_depth, "scope_depth must be positive"); | |
| 52 _bci = bci; | |
| 53 _pco = pco; | |
| 54 _scope_depth = scope_depth; | |
| 55 } | |
| 56 | |
| 57 int len() const { return _bci; } // for entry at subtable begin | |
| 58 int bci() const { return _bci; } | |
| 59 int pco() const { return _pco; } | |
| 60 int scope_depth() const { return _scope_depth; } | |
| 61 }; | |
| 62 | |
| 63 | |
| 64 // An ExceptionHandlerTable is an abstraction over a list of subtables | |
| 65 // of exception handlers for CatchNodes. Each subtable has a one-entry | |
| 66 // header holding length and catch_pco of the subtable, followed | |
| 67 // by 'length' entries for each exception handler that can be reached | |
| 68 // from the corresponding CatchNode. The catch_pco is the pc offset of | |
| 69 // the CatchNode in the corresponding nmethod. Empty subtables are dis- | |
| 70 // carded. | |
| 71 // | |
| 72 // Structure of the table: | |
| 73 // | |
| 74 // table = { subtable }. | |
| 75 // subtable = header entry { entry }. | |
| 76 // header = a pair (number of subtable entries, catch pc offset, [unused]) | |
| 77 // entry = a pair (handler bci, handler pc offset, scope depth) | |
| 78 // | |
| 79 // An ExceptionHandlerTable can be created from scratch, in which case | |
| 80 // it is possible to add subtables. It can also be created from an | |
| 81 // nmethod (for lookup purposes) in which case the table cannot be | |
| 82 // modified. | |
| 83 | |
| 84 class nmethod; | |
| 85 class ExceptionHandlerTable VALUE_OBJ_CLASS_SPEC { | |
| 86 private: | |
| 87 HandlerTableEntry* _table; // the table | |
| 88 int _length; // the current length of the table | |
| 89 int _size; // the number of allocated entries | |
| 90 ReallocMark _nesting; // assertion check for reallocations | |
| 91 | |
| 92 // add the entry & grow the table if needed | |
| 93 void add_entry(HandlerTableEntry entry); | |
| 94 HandlerTableEntry* subtable_for(int catch_pco) const; | |
| 95 | |
| 96 public: | |
| 97 // (compile-time) construction within compiler | |
| 98 ExceptionHandlerTable(int initial_size = 8); | |
| 99 | |
| 100 // (run-time) construction from nmethod | |
| 101 ExceptionHandlerTable(const nmethod* nm); | |
| 102 | |
| 103 // (compile-time) add entries | |
| 104 void add_subtable( | |
| 105 int catch_pco, // the pc offset for the CatchNode | |
| 106 GrowableArray<intptr_t>* handler_bcis, // the exception handler entry point bcis | |
| 107 GrowableArray<intptr_t>* scope_depths_from_top_scope, | |
| 108 // if representing exception handlers in multiple | |
| 109 // inlined scopes, indicates which scope relative to | |
| 110 // the youngest/innermost one in which we are performing | |
| 111 // the lookup; zero (or null GrowableArray) indicates | |
| 112 // innermost scope | |
| 113 GrowableArray<intptr_t>* handler_pcos // pc offsets for the compiled handlers | |
| 114 ); | |
| 115 | |
| 116 // nmethod support | |
| 117 int size_in_bytes() const { return round_to(_length * sizeof(HandlerTableEntry), oopSize); } | |
| 118 void copy_to(nmethod* nm); | |
| 119 | |
| 120 // lookup | |
| 121 HandlerTableEntry* entry_for(int catch_pco, int handler_bci, int scope_depth) const; | |
| 122 | |
| 123 // debugging | |
| 124 void print_subtable(HandlerTableEntry* t) const; | |
| 125 void print() const; | |
| 126 void print_subtable_for(int catch_pco) const; | |
| 127 }; | |
| 128 | |
| 129 | |
| 130 // ---------------------------------------------------------------------------- | |
| 131 // Implicit null exception tables. Maps an exception PC offset to a | |
| 132 // continuation PC offset. During construction it's a variable sized | |
| 133 // array with a max size and current length. When stored inside an | |
| 134 // nmethod a zero length table takes no space. This is detected by | |
| 135 // nul_chk_table_size() == 0. Otherwise the table has a length word | |
| 136 // followed by pairs of <excp-offset, const-offset>. | |
| 137 | |
| 138 // Use 32-bit representation for offsets | |
| 139 typedef uint implicit_null_entry; | |
| 140 | |
| 141 class ImplicitExceptionTable VALUE_OBJ_CLASS_SPEC { | |
| 142 uint _size; | |
| 143 uint _len; | |
| 144 implicit_null_entry *_data; | |
| 145 implicit_null_entry *adr( uint idx ) const { return &_data[2*idx]; } | |
| 146 ReallocMark _nesting; // assertion check for reallocations | |
| 147 public: | |
| 148 ImplicitExceptionTable( ) : _data(0), _size(0), _len(0) { } | |
| 149 // (run-time) construction from nmethod | |
| 150 ImplicitExceptionTable( const nmethod *nm ); | |
| 151 | |
| 152 void set_size( uint size ); | |
| 153 void append( uint exec_off, uint cont_off ); | |
| 154 uint at( uint exec_off ) const; | |
| 155 | |
| 156 uint len() const { return _len; } | |
| 157 int size_in_bytes() const { return len() == 0 ? 0 : ((2 * len() + 1) * sizeof(implicit_null_entry)); } | |
| 158 | |
| 159 void copy_to(nmethod* nm); | |
| 160 void print(address base) const; | |
| 161 void verify(nmethod *nm) const; | |
| 162 }; | |
| 163 | |
| 164 #endif // SHARE_VM_CODE_EXCEPTIONHANDLERTABLE_HPP |
