stubs.hpp revision 12422:98fe046473c9
1/* 2 * Copyright (c) 1997, 2016, 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 31// The classes in this file provide a simple framework for the 32// management of little pieces of machine code - or stubs - 33// created on the fly and frequently discarded. In this frame- 34// work stubs are stored in a queue. 35 36 37// Stub serves as abstract base class. A concrete stub 38// implementation is a subclass of Stub, implementing 39// all (non-virtual!) functions required sketched out 40// in the Stub class. 41// 42// A concrete stub layout may look like this (both data 43// and code sections could be empty as well): 44// 45// ________ 46// stub -->| | <--+ 47// | data | | 48// |________| | 49// code_begin -->| | | 50// | | | 51// | code | | size 52// | | | 53// |________| | 54// code_end -->| | | 55// | data | | 56// |________| | 57// <--+ 58 59 60class Stub VALUE_OBJ_CLASS_SPEC { 61 public: 62 // Initialization/finalization 63 void initialize(int size, 64 CodeStrings& strings) { ShouldNotCallThis(); } // called to initialize/specify the stub's size 65 void finalize() { ShouldNotCallThis(); } // called before the stub is deallocated 66 67 // General info/converters 68 int size() const { ShouldNotCallThis(); return 0; } // must return the size provided by initialize 69 static int code_size_to_size(int code_size) { ShouldNotCallThis(); return 0; } // computes the size given the code size 70 71 // Code info 72 address code_begin() const { ShouldNotCallThis(); return NULL; } // points to the first byte of the code 73 address code_end() const { ShouldNotCallThis(); return NULL; } // points to the first byte after the code 74 75 // Debugging 76 void verify() { ShouldNotCallThis(); } // verifies the Stub 77 void print() { ShouldNotCallThis(); } // prints some information about the stub 78}; 79 80 81// A stub interface defines the interface between a stub queue 82// and the stubs it queues. In order to avoid a vtable and 83// (and thus the extra word) in each stub, a concrete stub 84// interface object is created and associated with a stub 85// buffer which in turn uses the stub interface to interact 86// with its stubs. 87// 88// StubInterface serves as an abstract base class. A concrete 89// stub interface implementation is a subclass of StubInterface, 90// forwarding its virtual function calls to non-virtual calls 91// of the concrete stub (see also macro below). There's exactly 92// one stub interface instance required per stub queue. 93 94class StubInterface: public CHeapObj<mtCode> { 95 public: 96 // Initialization/finalization 97 virtual void initialize(Stub* self, int size, 98 CodeStrings& strings) = 0; // called after creation (called twice if allocated via (request, commit)) 99 virtual void finalize(Stub* self) = 0; // called before deallocation 100 101 // General info/converters 102 virtual int size(Stub* self) const = 0; // the total size of the stub in bytes (must be a multiple of CodeEntryAlignment) 103 virtual int code_size_to_size(int code_size) const = 0; // computes the total stub size in bytes given the code size in bytes 104 105 // Code info 106 virtual address code_begin(Stub* self) const = 0; // points to the first code byte 107 virtual address code_end(Stub* self) const = 0; // points to the first byte after the code 108 109 // Debugging 110 virtual void verify(Stub* self) = 0; // verifies the stub 111 virtual void print(Stub* self) = 0; // prints information about the stub 112}; 113 114 115// DEF_STUB_INTERFACE is used to create a concrete stub interface 116// class, forwarding stub interface calls to the corresponding 117// stub calls. 118 119#define DEF_STUB_INTERFACE(stub) \ 120 class stub##Interface: public StubInterface { \ 121 private: \ 122 static stub* cast(Stub* self) { return (stub*)self; } \ 123 \ 124 public: \ 125 /* Initialization/finalization */ \ 126 virtual void initialize(Stub* self, int size, \ 127 CodeStrings& strings) { cast(self)->initialize(size, strings); } \ 128 virtual void finalize(Stub* self) { cast(self)->finalize(); } \ 129 \ 130 /* General info */ \ 131 virtual int size(Stub* self) const { return cast(self)->size(); } \ 132 virtual int code_size_to_size(int code_size) const { return stub::code_size_to_size(code_size); } \ 133 \ 134 /* Code info */ \ 135 virtual address code_begin(Stub* self) const { return cast(self)->code_begin(); } \ 136 virtual address code_end(Stub* self) const { return cast(self)->code_end(); } \ 137 \ 138 /* Debugging */ \ 139 virtual void verify(Stub* self) { cast(self)->verify(); } \ 140 virtual void print(Stub* self) { cast(self)->print(); } \ 141 }; 142 143 144// A StubQueue maintains a queue of stubs. 145// Note: All sizes (spaces) are given in bytes. 146 147class StubQueue: public CHeapObj<mtCode> { 148 friend class VMStructs; 149 private: 150 StubInterface* _stub_interface; // the interface prototype 151 address _stub_buffer; // where all stubs are stored 152 int _buffer_size; // the buffer size in bytes 153 int _buffer_limit; // the (byte) index of the actual buffer limit (_buffer_limit <= _buffer_size) 154 int _queue_begin; // the (byte) index of the first queue entry (word-aligned) 155 int _queue_end; // the (byte) index of the first entry after the queue (word-aligned) 156 int _number_of_stubs; // the number of buffered stubs 157 Mutex* const _mutex; // the lock used for a (request, commit) transaction 158 159 void check_index(int i) const { assert(0 <= i && i < _buffer_limit && i % CodeEntryAlignment == 0, "illegal index"); } 160 bool is_contiguous() const { return _queue_begin <= _queue_end; } 161 int index_of(Stub* s) const { int i = (address)s - _stub_buffer; check_index(i); return i; } 162 Stub* stub_at(int i) const { check_index(i); return (Stub*)(_stub_buffer + i); } 163 Stub* current_stub() const { return stub_at(_queue_end); } 164 165 // Stub functionality accessed via interface 166 void stub_initialize(Stub* s, int size, 167 CodeStrings& strings) { assert(size % CodeEntryAlignment == 0, "size not aligned"); _stub_interface->initialize(s, size, strings); } 168 void stub_finalize(Stub* s) { _stub_interface->finalize(s); } 169 int stub_size(Stub* s) const { return _stub_interface->size(s); } 170 bool stub_contains(Stub* s, address pc) const { return _stub_interface->code_begin(s) <= pc && pc < _stub_interface->code_end(s); } 171 int stub_code_size_to_size(int code_size) const { return _stub_interface->code_size_to_size(code_size); } 172 void stub_verify(Stub* s) { _stub_interface->verify(s); } 173 void stub_print(Stub* s) { _stub_interface->print(s); } 174 175 static void register_queue(StubQueue*); 176 177 public: 178 StubQueue(StubInterface* stub_interface, int buffer_size, Mutex* lock, 179 const char* name); 180 ~StubQueue(); 181 182 // General queue info 183 bool is_empty() const { return _queue_begin == _queue_end; } 184 int total_space() const { return _buffer_size - 1; } 185 int available_space() const { int d = _queue_begin - _queue_end - 1; return d < 0 ? d + _buffer_size : d; } 186 int used_space() const { return total_space() - available_space(); } 187 int number_of_stubs() const { return _number_of_stubs; } 188 bool contains(address pc) const { return _stub_buffer <= pc && pc < _stub_buffer + _buffer_limit; } 189 Stub* stub_containing(address pc) const; 190 address code_start() const { return _stub_buffer; } 191 address code_end() const { return _stub_buffer + _buffer_limit; } 192 193 // Stub allocation (atomic transactions) 194 Stub* request_committed(int code_size); // request a stub that provides exactly code_size space for code 195 Stub* request(int requested_code_size); // request a stub with a (maximum) code space - locks the queue 196 void commit (int committed_code_size, 197 CodeStrings& strings); // commit the previously requested stub - unlocks the queue 198 199 // Stub deallocation 200 void remove_first(); // remove the first stub in the queue 201 void remove_first(int n); // remove the first n stubs in the queue 202 void remove_all(); // remove all stubs in the queue 203 204 // Iteration 205 static void queues_do(void f(StubQueue* s)); // call f with each StubQueue 206 void stubs_do(void f(Stub* s)); // call f with all stubs 207 Stub* first() const { return number_of_stubs() > 0 ? stub_at(_queue_begin) : NULL; } 208 Stub* next(Stub* s) const { int i = index_of(s) + stub_size(s); 209 if (i == _buffer_limit) i = 0; 210 return (i == _queue_end) ? NULL : stub_at(i); 211 } 212 213 address stub_code_begin(Stub* s) const { return _stub_interface->code_begin(s); } 214 address stub_code_end(Stub* s) const { return _stub_interface->code_end(s); } 215 216 // Debugging/printing 217 void verify(); // verifies the stub queue 218 void print(); // prints information about the stub queue 219 220}; 221 222#endif // SHARE_VM_CODE_STUBS_HPP 223