stubs.hpp revision 1472:c18cbe5936b8
1/* 2 * Copyright (c) 1997, 2002, 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// The classes in this file provide a simple framework for the 26// management of little pieces of machine code - or stubs - 27// created on the fly and frequently discarded. In this frame- 28// work stubs are stored in a queue. 29 30 31// Stub serves as abstract base class. A concrete stub 32// implementation is a subclass of Stub, implementing 33// all (non-virtual!) functions required sketched out 34// in the Stub class. 35// 36// A concrete stub layout may look like this (both data 37// and code sections could be empty as well): 38// 39// ________ 40// stub -->| | <--+ 41// | data | | 42// |________| | 43// code_begin -->| | | 44// | | | 45// | code | | size 46// | | | 47// |________| | 48// code_end -->| | | 49// | data | | 50// |________| | 51// <--+ 52 53 54class Stub VALUE_OBJ_CLASS_SPEC { 55 public: 56 // Initialization/finalization 57 void initialize(int size) { ShouldNotCallThis(); } // called to initialize/specify the stub's size 58 void finalize() { ShouldNotCallThis(); } // called before the stub is deallocated 59 60 // General info/converters 61 int size() const { ShouldNotCallThis(); return 0; } // must return the size provided by initialize 62 static int code_size_to_size(int code_size) { ShouldNotCallThis(); return 0; } // computes the size given the code size 63 64 // Code info 65 address code_begin() const { ShouldNotCallThis(); return NULL; } // points to the first byte of the code 66 address code_end() const { ShouldNotCallThis(); return NULL; } // points to the first byte after the code 67 68 // Debugging 69 void verify() { ShouldNotCallThis(); } // verifies the Stub 70 void print() { ShouldNotCallThis(); } // prints some information about the stub 71}; 72 73 74// A stub interface defines the interface between a stub queue 75// and the stubs it queues. In order to avoid a vtable and 76// (and thus the extra word) in each stub, a concrete stub 77// interface object is created and associated with a stub 78// buffer which in turn uses the stub interface to interact 79// with its stubs. 80// 81// StubInterface serves as an abstract base class. A concrete 82// stub interface implementation is a subclass of StubInterface, 83// forwarding its virtual function calls to non-virtual calls 84// of the concrete stub (see also macro below). There's exactly 85// one stub interface instance required per stub queue. 86 87class StubInterface: public CHeapObj { 88 public: 89 // Initialization/finalization 90 virtual void initialize(Stub* self, int size) = 0; // called after creation (called twice if allocated via (request, commit)) 91 virtual void finalize(Stub* self) = 0; // called before deallocation 92 93 // General info/converters 94 virtual int size(Stub* self) const = 0; // the total size of the stub in bytes (must be a multiple of CodeEntryAlignment) 95 virtual int code_size_to_size(int code_size) const = 0; // computes the total stub size in bytes given the code size in bytes 96 97 // Code info 98 virtual address code_begin(Stub* self) const = 0; // points to the first code byte 99 virtual address code_end(Stub* self) const = 0; // points to the first byte after the code 100 101 // Debugging 102 virtual void verify(Stub* self) = 0; // verifies the stub 103 virtual void print(Stub* self) = 0; // prints information about the stub 104}; 105 106 107// DEF_STUB_INTERFACE is used to create a concrete stub interface 108// class, forwarding stub interface calls to the corresponding 109// stub calls. 110 111#define DEF_STUB_INTERFACE(stub) \ 112 class stub##Interface: public StubInterface { \ 113 private: \ 114 static stub* cast(Stub* self) { return (stub*)self; } \ 115 \ 116 public: \ 117 /* Initialization/finalization */ \ 118 virtual void initialize(Stub* self, int size) { cast(self)->initialize(size); } \ 119 virtual void finalize(Stub* self) { cast(self)->finalize(); } \ 120 \ 121 /* General info */ \ 122 virtual int size(Stub* self) const { return cast(self)->size(); } \ 123 virtual int code_size_to_size(int code_size) const { return stub::code_size_to_size(code_size); } \ 124 \ 125 /* Code info */ \ 126 virtual address code_begin(Stub* self) const { return cast(self)->code_begin(); } \ 127 virtual address code_end(Stub* self) const { return cast(self)->code_end(); } \ 128 \ 129 /* Debugging */ \ 130 virtual void verify(Stub* self) { cast(self)->verify(); } \ 131 virtual void print(Stub* self) { cast(self)->print(); } \ 132 }; 133 134 135// A StubQueue maintains a queue of stubs. 136// Note: All sizes (spaces) are given in bytes. 137 138class StubQueue: public CHeapObj { 139 friend class VMStructs; 140 private: 141 StubInterface* _stub_interface; // the interface prototype 142 address _stub_buffer; // where all stubs are stored 143 int _buffer_size; // the buffer size in bytes 144 int _buffer_limit; // the (byte) index of the actual buffer limit (_buffer_limit <= _buffer_size) 145 int _queue_begin; // the (byte) index of the first queue entry (word-aligned) 146 int _queue_end; // the (byte) index of the first entry after the queue (word-aligned) 147 int _number_of_stubs; // the number of buffered stubs 148 Mutex* const _mutex; // the lock used for a (request, commit) transaction 149 150 void check_index(int i) const { assert(0 <= i && i < _buffer_limit && i % CodeEntryAlignment == 0, "illegal index"); } 151 bool is_contiguous() const { return _queue_begin <= _queue_end; } 152 int index_of(Stub* s) const { int i = (address)s - _stub_buffer; check_index(i); return i; } 153 Stub* stub_at(int i) const { check_index(i); return (Stub*)(_stub_buffer + i); } 154 Stub* current_stub() const { return stub_at(_queue_end); } 155 156 // Stub functionality accessed via interface 157 void stub_initialize(Stub* s, int size) { assert(size % CodeEntryAlignment == 0, "size not aligned"); _stub_interface->initialize(s, size); } 158 void stub_finalize(Stub* s) { _stub_interface->finalize(s); } 159 int stub_size(Stub* s) const { return _stub_interface->size(s); } 160 bool stub_contains(Stub* s, address pc) const { return _stub_interface->code_begin(s) <= pc && pc < _stub_interface->code_end(s); } 161 int stub_code_size_to_size(int code_size) const { return _stub_interface->code_size_to_size(code_size); } 162 void stub_verify(Stub* s) { _stub_interface->verify(s); } 163 void stub_print(Stub* s) { _stub_interface->print(s); } 164 165 static void register_queue(StubQueue*); 166 167 public: 168 StubQueue(StubInterface* stub_interface, int buffer_size, Mutex* lock, 169 const char* name); 170 ~StubQueue(); 171 172 // General queue info 173 bool is_empty() const { return _queue_begin == _queue_end; } 174 int total_space() const { return _buffer_size - 1; } 175 int available_space() const { int d = _queue_begin - _queue_end - 1; return d < 0 ? d + _buffer_size : d; } 176 int used_space() const { return total_space() - available_space(); } 177 int number_of_stubs() const { return _number_of_stubs; } 178 bool contains(address pc) const { return _stub_buffer <= pc && pc < _stub_buffer + _buffer_limit; } 179 Stub* stub_containing(address pc) const; 180 address code_start() const { return _stub_buffer; } 181 address code_end() const { return _stub_buffer + _buffer_limit; } 182 183 // Stub allocation (atomic transactions) 184 Stub* request_committed(int code_size); // request a stub that provides exactly code_size space for code 185 Stub* request(int requested_code_size); // request a stub with a (maximum) code space - locks the queue 186 void commit (int committed_code_size); // commit the previously requested stub - unlocks the queue 187 188 // Stub deallocation 189 void remove_first(); // remove the first stub in the queue 190 void remove_first(int n); // remove the first n stubs in the queue 191 void remove_all(); // remove all stubs in the queue 192 193 // Iteration 194 static void queues_do(void f(StubQueue* s)); // call f with each StubQueue 195 void stubs_do(void f(Stub* s)); // call f with all stubs 196 Stub* first() const { return number_of_stubs() > 0 ? stub_at(_queue_begin) : NULL; } 197 Stub* next(Stub* s) const { int i = index_of(s) + stub_size(s); 198 if (i == _buffer_limit) i = 0; 199 return (i == _queue_end) ? NULL : stub_at(i); 200 } 201 202 address stub_code_begin(Stub* s) const { return _stub_interface->code_begin(s); } 203 address stub_code_end(Stub* s) const { return _stub_interface->code_end(s); } 204 205 // Debugging/printing 206 void verify(); // verifies the stub queue 207 void print(); // prints information about the stub queue 208}; 209