stubs.hpp revision 3465:d2a62e0f25eb
1/* 2 * Copyright (c) 1997, 2010, 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_STUBS_HPP 26#define SHARE_VM_CODE_STUBS_HPP 27 28#include "memory/allocation.hpp" 29#ifdef TARGET_OS_FAMILY_linux 30# include "os_linux.inline.hpp" 31#endif 32#ifdef TARGET_OS_FAMILY_solaris 33# include "os_solaris.inline.hpp" 34#endif 35#ifdef TARGET_OS_FAMILY_windows 36# include "os_windows.inline.hpp" 37#endif 38#ifdef TARGET_OS_FAMILY_bsd 39# include "os_bsd.inline.hpp" 40#endif 41 42// The classes in this file provide a simple framework for the 43// management of little pieces of machine code - or stubs - 44// created on the fly and frequently discarded. In this frame- 45// work stubs are stored in a queue. 46 47 48// Stub serves as abstract base class. A concrete stub 49// implementation is a subclass of Stub, implementing 50// all (non-virtual!) functions required sketched out 51// in the Stub class. 52// 53// A concrete stub layout may look like this (both data 54// and code sections could be empty as well): 55// 56// ________ 57// stub -->| | <--+ 58// | data | | 59// |________| | 60// code_begin -->| | | 61// | | | 62// | code | | size 63// | | | 64// |________| | 65// code_end -->| | | 66// | data | | 67// |________| | 68// <--+ 69 70 71class Stub VALUE_OBJ_CLASS_SPEC { 72 public: 73 // Initialization/finalization 74 void initialize(int size) { ShouldNotCallThis(); } // called to initialize/specify the stub's size 75 void finalize() { ShouldNotCallThis(); } // called before the stub is deallocated 76 77 // General info/converters 78 int size() const { ShouldNotCallThis(); return 0; } // must return the size provided by initialize 79 static int code_size_to_size(int code_size) { ShouldNotCallThis(); return 0; } // computes the size given the code size 80 81 // Code info 82 address code_begin() const { ShouldNotCallThis(); return NULL; } // points to the first byte of the code 83 address code_end() const { ShouldNotCallThis(); return NULL; } // points to the first byte after the code 84 85 // Debugging 86 void verify() { ShouldNotCallThis(); } // verifies the Stub 87 void print() { ShouldNotCallThis(); } // prints some information about the stub 88}; 89 90 91// A stub interface defines the interface between a stub queue 92// and the stubs it queues. In order to avoid a vtable and 93// (and thus the extra word) in each stub, a concrete stub 94// interface object is created and associated with a stub 95// buffer which in turn uses the stub interface to interact 96// with its stubs. 97// 98// StubInterface serves as an abstract base class. A concrete 99// stub interface implementation is a subclass of StubInterface, 100// forwarding its virtual function calls to non-virtual calls 101// of the concrete stub (see also macro below). There's exactly 102// one stub interface instance required per stub queue. 103 104class StubInterface: public CHeapObj<mtCode> { 105 public: 106 // Initialization/finalization 107 virtual void initialize(Stub* self, int size) = 0; // called after creation (called twice if allocated via (request, commit)) 108 virtual void finalize(Stub* self) = 0; // called before deallocation 109 110 // General info/converters 111 virtual int size(Stub* self) const = 0; // the total size of the stub in bytes (must be a multiple of CodeEntryAlignment) 112 virtual int code_size_to_size(int code_size) const = 0; // computes the total stub size in bytes given the code size in bytes 113 114 // Code info 115 virtual address code_begin(Stub* self) const = 0; // points to the first code byte 116 virtual address code_end(Stub* self) const = 0; // points to the first byte after the code 117 118 // Debugging 119 virtual void verify(Stub* self) = 0; // verifies the stub 120 virtual void print(Stub* self) = 0; // prints information about the stub 121}; 122 123 124// DEF_STUB_INTERFACE is used to create a concrete stub interface 125// class, forwarding stub interface calls to the corresponding 126// stub calls. 127 128#define DEF_STUB_INTERFACE(stub) \ 129 class stub##Interface: public StubInterface { \ 130 private: \ 131 static stub* cast(Stub* self) { return (stub*)self; } \ 132 \ 133 public: \ 134 /* Initialization/finalization */ \ 135 virtual void initialize(Stub* self, int size) { cast(self)->initialize(size); } \ 136 virtual void finalize(Stub* self) { cast(self)->finalize(); } \ 137 \ 138 /* General info */ \ 139 virtual int size(Stub* self) const { return cast(self)->size(); } \ 140 virtual int code_size_to_size(int code_size) const { return stub::code_size_to_size(code_size); } \ 141 \ 142 /* Code info */ \ 143 virtual address code_begin(Stub* self) const { return cast(self)->code_begin(); } \ 144 virtual address code_end(Stub* self) const { return cast(self)->code_end(); } \ 145 \ 146 /* Debugging */ \ 147 virtual void verify(Stub* self) { cast(self)->verify(); } \ 148 virtual void print(Stub* self) { cast(self)->print(); } \ 149 }; 150 151 152// A StubQueue maintains a queue of stubs. 153// Note: All sizes (spaces) are given in bytes. 154 155class StubQueue: public CHeapObj<mtCode> { 156 friend class VMStructs; 157 private: 158 StubInterface* _stub_interface; // the interface prototype 159 address _stub_buffer; // where all stubs are stored 160 int _buffer_size; // the buffer size in bytes 161 int _buffer_limit; // the (byte) index of the actual buffer limit (_buffer_limit <= _buffer_size) 162 int _queue_begin; // the (byte) index of the first queue entry (word-aligned) 163 int _queue_end; // the (byte) index of the first entry after the queue (word-aligned) 164 int _number_of_stubs; // the number of buffered stubs 165 Mutex* const _mutex; // the lock used for a (request, commit) transaction 166 167 void check_index(int i) const { assert(0 <= i && i < _buffer_limit && i % CodeEntryAlignment == 0, "illegal index"); } 168 bool is_contiguous() const { return _queue_begin <= _queue_end; } 169 int index_of(Stub* s) const { int i = (address)s - _stub_buffer; check_index(i); return i; } 170 Stub* stub_at(int i) const { check_index(i); return (Stub*)(_stub_buffer + i); } 171 Stub* current_stub() const { return stub_at(_queue_end); } 172 173 // Stub functionality accessed via interface 174 void stub_initialize(Stub* s, int size) { assert(size % CodeEntryAlignment == 0, "size not aligned"); _stub_interface->initialize(s, size); } 175 void stub_finalize(Stub* s) { _stub_interface->finalize(s); } 176 int stub_size(Stub* s) const { return _stub_interface->size(s); } 177 bool stub_contains(Stub* s, address pc) const { return _stub_interface->code_begin(s) <= pc && pc < _stub_interface->code_end(s); } 178 int stub_code_size_to_size(int code_size) const { return _stub_interface->code_size_to_size(code_size); } 179 void stub_verify(Stub* s) { _stub_interface->verify(s); } 180 void stub_print(Stub* s) { _stub_interface->print(s); } 181 182 static void register_queue(StubQueue*); 183 184 public: 185 StubQueue(StubInterface* stub_interface, int buffer_size, Mutex* lock, 186 const char* name); 187 ~StubQueue(); 188 189 // General queue info 190 bool is_empty() const { return _queue_begin == _queue_end; } 191 int total_space() const { return _buffer_size - 1; } 192 int available_space() const { int d = _queue_begin - _queue_end - 1; return d < 0 ? d + _buffer_size : d; } 193 int used_space() const { return total_space() - available_space(); } 194 int number_of_stubs() const { return _number_of_stubs; } 195 bool contains(address pc) const { return _stub_buffer <= pc && pc < _stub_buffer + _buffer_limit; } 196 Stub* stub_containing(address pc) const; 197 address code_start() const { return _stub_buffer; } 198 address code_end() const { return _stub_buffer + _buffer_limit; } 199 200 // Stub allocation (atomic transactions) 201 Stub* request_committed(int code_size); // request a stub that provides exactly code_size space for code 202 Stub* request(int requested_code_size); // request a stub with a (maximum) code space - locks the queue 203 void commit (int committed_code_size); // commit the previously requested stub - unlocks the queue 204 205 // Stub deallocation 206 void remove_first(); // remove the first stub in the queue 207 void remove_first(int n); // remove the first n stubs in the queue 208 void remove_all(); // remove all stubs in the queue 209 210 // Iteration 211 static void queues_do(void f(StubQueue* s)); // call f with each StubQueue 212 void stubs_do(void f(Stub* s)); // call f with all stubs 213 Stub* first() const { return number_of_stubs() > 0 ? stub_at(_queue_begin) : NULL; } 214 Stub* next(Stub* s) const { int i = index_of(s) + stub_size(s); 215 if (i == _buffer_limit) i = 0; 216 return (i == _queue_end) ? NULL : stub_at(i); 217 } 218 219 address stub_code_begin(Stub* s) const { return _stub_interface->code_begin(s); } 220 address stub_code_end(Stub* s) const { return _stub_interface->code_end(s); } 221 222 // Debugging/printing 223 void verify(); // verifies the stub queue 224 void print(); // prints information about the stub queue 225}; 226 227#endif // SHARE_VM_CODE_STUBS_HPP 228