stubs.hpp revision 5776:de6a9e811145
1/* 2 * Copyright (c) 1997, 2013, 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 "asm/codeBuffer.hpp" 29#include "memory/allocation.hpp" 30#ifdef TARGET_OS_FAMILY_linux 31# include "os_linux.inline.hpp" 32#endif 33#ifdef TARGET_OS_FAMILY_solaris 34# include "os_solaris.inline.hpp" 35#endif 36#ifdef TARGET_OS_FAMILY_windows 37# include "os_windows.inline.hpp" 38#endif 39#ifdef TARGET_OS_FAMILY_bsd 40# include "os_bsd.inline.hpp" 41#endif 42 43// The classes in this file provide a simple framework for the 44// management of little pieces of machine code - or stubs - 45// created on the fly and frequently discarded. In this frame- 46// work stubs are stored in a queue. 47 48 49// Stub serves as abstract base class. A concrete stub 50// implementation is a subclass of Stub, implementing 51// all (non-virtual!) functions required sketched out 52// in the Stub class. 53// 54// A concrete stub layout may look like this (both data 55// and code sections could be empty as well): 56// 57// ________ 58// stub -->| | <--+ 59// | data | | 60// |________| | 61// code_begin -->| | | 62// | | | 63// | code | | size 64// | | | 65// |________| | 66// code_end -->| | | 67// | data | | 68// |________| | 69// <--+ 70 71 72class Stub VALUE_OBJ_CLASS_SPEC { 73 public: 74 // Initialization/finalization 75 void initialize(int size, 76 CodeStrings& strings) { ShouldNotCallThis(); } // called to initialize/specify the stub's size 77 void finalize() { ShouldNotCallThis(); } // called before the stub is deallocated 78 79 // General info/converters 80 int size() const { ShouldNotCallThis(); return 0; } // must return the size provided by initialize 81 static int code_size_to_size(int code_size) { ShouldNotCallThis(); return 0; } // computes the size given the code size 82 83 // Code info 84 address code_begin() const { ShouldNotCallThis(); return NULL; } // points to the first byte of the code 85 address code_end() const { ShouldNotCallThis(); return NULL; } // points to the first byte after the code 86 87 // Debugging 88 void verify() { ShouldNotCallThis(); } // verifies the Stub 89 void print() { ShouldNotCallThis(); } // prints some information about the stub 90}; 91 92 93// A stub interface defines the interface between a stub queue 94// and the stubs it queues. In order to avoid a vtable and 95// (and thus the extra word) in each stub, a concrete stub 96// interface object is created and associated with a stub 97// buffer which in turn uses the stub interface to interact 98// with its stubs. 99// 100// StubInterface serves as an abstract base class. A concrete 101// stub interface implementation is a subclass of StubInterface, 102// forwarding its virtual function calls to non-virtual calls 103// of the concrete stub (see also macro below). There's exactly 104// one stub interface instance required per stub queue. 105 106class StubInterface: public CHeapObj<mtCode> { 107 public: 108 // Initialization/finalization 109 virtual void initialize(Stub* self, int size, 110 CodeStrings& strings) = 0; // called after creation (called twice if allocated via (request, commit)) 111 virtual void finalize(Stub* self) = 0; // called before deallocation 112 113 // General info/converters 114 virtual int size(Stub* self) const = 0; // the total size of the stub in bytes (must be a multiple of CodeEntryAlignment) 115 virtual int code_size_to_size(int code_size) const = 0; // computes the total stub size in bytes given the code size in bytes 116 117 // Code info 118 virtual address code_begin(Stub* self) const = 0; // points to the first code byte 119 virtual address code_end(Stub* self) const = 0; // points to the first byte after the code 120 121 // Debugging 122 virtual void verify(Stub* self) = 0; // verifies the stub 123 virtual void print(Stub* self) = 0; // prints information about the stub 124}; 125 126 127// DEF_STUB_INTERFACE is used to create a concrete stub interface 128// class, forwarding stub interface calls to the corresponding 129// stub calls. 130 131#define DEF_STUB_INTERFACE(stub) \ 132 class stub##Interface: public StubInterface { \ 133 private: \ 134 static stub* cast(Stub* self) { return (stub*)self; } \ 135 \ 136 public: \ 137 /* Initialization/finalization */ \ 138 virtual void initialize(Stub* self, int size, \ 139 CodeStrings& strings) { cast(self)->initialize(size, strings); } \ 140 virtual void finalize(Stub* self) { cast(self)->finalize(); } \ 141 \ 142 /* General info */ \ 143 virtual int size(Stub* self) const { return cast(self)->size(); } \ 144 virtual int code_size_to_size(int code_size) const { return stub::code_size_to_size(code_size); } \ 145 \ 146 /* Code info */ \ 147 virtual address code_begin(Stub* self) const { return cast(self)->code_begin(); } \ 148 virtual address code_end(Stub* self) const { return cast(self)->code_end(); } \ 149 \ 150 /* Debugging */ \ 151 virtual void verify(Stub* self) { cast(self)->verify(); } \ 152 virtual void print(Stub* self) { cast(self)->print(); } \ 153 }; 154 155 156// A StubQueue maintains a queue of stubs. 157// Note: All sizes (spaces) are given in bytes. 158 159class StubQueue: public CHeapObj<mtCode> { 160 friend class VMStructs; 161 private: 162 StubInterface* _stub_interface; // the interface prototype 163 address _stub_buffer; // where all stubs are stored 164 int _buffer_size; // the buffer size in bytes 165 int _buffer_limit; // the (byte) index of the actual buffer limit (_buffer_limit <= _buffer_size) 166 int _queue_begin; // the (byte) index of the first queue entry (word-aligned) 167 int _queue_end; // the (byte) index of the first entry after the queue (word-aligned) 168 int _number_of_stubs; // the number of buffered stubs 169 Mutex* const _mutex; // the lock used for a (request, commit) transaction 170 171 void check_index(int i) const { assert(0 <= i && i < _buffer_limit && i % CodeEntryAlignment == 0, "illegal index"); } 172 bool is_contiguous() const { return _queue_begin <= _queue_end; } 173 int index_of(Stub* s) const { int i = (address)s - _stub_buffer; check_index(i); return i; } 174 Stub* stub_at(int i) const { check_index(i); return (Stub*)(_stub_buffer + i); } 175 Stub* current_stub() const { return stub_at(_queue_end); } 176 177 // Stub functionality accessed via interface 178 void stub_initialize(Stub* s, int size, 179 CodeStrings& strings) { assert(size % CodeEntryAlignment == 0, "size not aligned"); _stub_interface->initialize(s, size, strings); } 180 void stub_finalize(Stub* s) { _stub_interface->finalize(s); } 181 int stub_size(Stub* s) const { return _stub_interface->size(s); } 182 bool stub_contains(Stub* s, address pc) const { return _stub_interface->code_begin(s) <= pc && pc < _stub_interface->code_end(s); } 183 int stub_code_size_to_size(int code_size) const { return _stub_interface->code_size_to_size(code_size); } 184 void stub_verify(Stub* s) { _stub_interface->verify(s); } 185 void stub_print(Stub* s) { _stub_interface->print(s); } 186 187 static void register_queue(StubQueue*); 188 189 public: 190 StubQueue(StubInterface* stub_interface, int buffer_size, Mutex* lock, 191 const char* name); 192 ~StubQueue(); 193 194 // General queue info 195 bool is_empty() const { return _queue_begin == _queue_end; } 196 int total_space() const { return _buffer_size - 1; } 197 int available_space() const { int d = _queue_begin - _queue_end - 1; return d < 0 ? d + _buffer_size : d; } 198 int used_space() const { return total_space() - available_space(); } 199 int number_of_stubs() const { return _number_of_stubs; } 200 bool contains(address pc) const { return _stub_buffer <= pc && pc < _stub_buffer + _buffer_limit; } 201 Stub* stub_containing(address pc) const; 202 address code_start() const { return _stub_buffer; } 203 address code_end() const { return _stub_buffer + _buffer_limit; } 204 205 // Stub allocation (atomic transactions) 206 Stub* request_committed(int code_size); // request a stub that provides exactly code_size space for code 207 Stub* request(int requested_code_size); // request a stub with a (maximum) code space - locks the queue 208 void commit (int committed_code_size, 209 CodeStrings& strings); // commit the previously requested stub - unlocks the queue 210 211 // Stub deallocation 212 void remove_first(); // remove the first stub in the queue 213 void remove_first(int n); // remove the first n stubs in the queue 214 void remove_all(); // remove all stubs in the queue 215 216 // Iteration 217 static void queues_do(void f(StubQueue* s)); // call f with each StubQueue 218 void stubs_do(void f(Stub* s)); // call f with all stubs 219 Stub* first() const { return number_of_stubs() > 0 ? stub_at(_queue_begin) : NULL; } 220 Stub* next(Stub* s) const { int i = index_of(s) + stub_size(s); 221 if (i == _buffer_limit) i = 0; 222 return (i == _queue_end) ? NULL : stub_at(i); 223 } 224 225 address stub_code_begin(Stub* s) const { return _stub_interface->code_begin(s); } 226 address stub_code_end(Stub* s) const { return _stub_interface->code_end(s); } 227 228 // Debugging/printing 229 void verify(); // verifies the stub queue 230 void print(); // prints information about the stub queue 231}; 232 233#endif // SHARE_VM_CODE_STUBS_HPP 234