| /* | |
| * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved. | |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| * | |
| * This code is free software; you can redistribute it and/or modify it | |
| * under the terms of the GNU General Public License version 2 only, as | |
| * published by the Free Software Foundation. | |
| * | |
| * This code is distributed in the hope that it will be useful, but WITHOUT | |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| * version 2 for more details (a copy is included in the LICENSE file that | |
| * accompanied this code). | |
| * | |
| * You should have received a copy of the GNU General Public License version | |
| * 2 along with this work; if not, write to the Free Software Foundation, | |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| * | |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
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| * | |
| */ | |
| #ifndef SHARE_CODE_STUBS_HPP | |
| #define SHARE_CODE_STUBS_HPP | |
| #include "asm/codeBuffer.hpp" | |
| #include "memory/allocation.hpp" | |
| class Mutex; | |
| // The classes in this file provide a simple framework for the | |
| // management of little pieces of machine code - or stubs - | |
| // created on the fly and frequently discarded. In this frame- | |
| // work stubs are stored in a queue. | |
| // Stub serves as abstract base class. A concrete stub | |
| // implementation is a subclass of Stub, implementing | |
| // all (non-virtual!) functions required sketched out | |
| // in the Stub class. | |
| // | |
| // A concrete stub layout may look like this (both data | |
| // and code sections could be empty as well): | |
| // | |
| // | |
| // stub -->|--------| <--+ <--- aligned by alignment() | |
| // | | | | |
| // | data | | | |
| // | | | | |
| // code_begin -->|--------| | <--- aligned by code_alignment() | |
| // | | | | |
| // | | | | |
| // | code | | size | |
| // | | | | |
| // | | | | |
| // code_end -->|--------| <--+ | |
| // | |
| class Stub { | |
| public: | |
| // Initialization/finalization | |
| void initialize(int size) { ShouldNotCallThis(); } // called to initialize/specify the stub's size | |
| void finalize() { ShouldNotCallThis(); } // called before the stub is deallocated | |
| // General info/converters | |
| int size() const { ShouldNotCallThis(); return 0; } // must return the size provided by initialize | |
| // Code info | |
| address code_begin() const { ShouldNotCallThis(); return nullptr; } // points to the first byte of the code | |
| address code_end() const { ShouldNotCallThis(); return nullptr; } // points to the first byte after the code | |
| // Debugging | |
| void verify() { ShouldNotCallThis(); } // verifies the Stub | |
| void print() { ShouldNotCallThis(); } // prints some information about the stub | |
| }; | |
| // A stub interface defines the interface between a stub queue | |
| // and the stubs it queues. In order to avoid a vtable and | |
| // (and thus the extra word) in each stub, a concrete stub | |
| // interface object is created and associated with a stub | |
| // buffer which in turn uses the stub interface to interact | |
| // with its stubs. | |
| // | |
| // StubInterface serves as an abstract base class. A concrete | |
| // stub interface implementation is a subclass of StubInterface, | |
| // forwarding its virtual function calls to non-virtual calls | |
| // of the concrete stub (see also macro below). There's exactly | |
| // one stub interface instance required per stub queue. | |
| class StubInterface: public CHeapObj<mtCode> { | |
| public: | |
| // Initialization/finalization | |
| virtual void initialize(Stub* self, int size) = 0; // called after creation (called twice if allocated via (request, commit)) | |
| virtual void finalize(Stub* self) = 0; // called before deallocation | |
| // General info/converters | |
| virtual int size(Stub* self) const = 0; // the total size of the stub in bytes (must be a multiple of HeapWordSize) | |
| virtual int alignment() const = 0; // computes the alignment | |
| virtual int code_alignment() const = 0; // computes the code alignment | |
| // Code info | |
| virtual address code_begin(Stub* self) const = 0; // points to the first code byte | |
| virtual address code_end(Stub* self) const = 0; // points to the first byte after the code | |
| // Debugging | |
| virtual void verify(Stub* self) = 0; // verifies the stub | |
| virtual void print(Stub* self) = 0; // prints information about the stub | |
| }; | |
| // DEF_STUB_INTERFACE is used to create a concrete stub interface | |
| // class, forwarding stub interface calls to the corresponding | |
| // stub calls. | |
| #define DEF_STUB_INTERFACE(stub) \ | |
| class stub##Interface: public StubInterface { \ | |
| private: \ | |
| static stub* cast(Stub* self) { return (stub*)self; } \ | |
| \ | |
| public: \ | |
| /* Initialization/finalization */ \ | |
| virtual void initialize(Stub* self, int size) { cast(self)->initialize(size); } \ | |
| virtual void finalize(Stub* self) { cast(self)->finalize(); } \ | |
| \ | |
| /* General info */ \ | |
| virtual int size(Stub* self) const { return cast(self)->size(); } \ | |
| virtual int alignment() const { return stub::alignment(); } \ | |
| virtual int code_alignment() const { return stub::code_alignment(); } \ | |
| \ | |
| /* Code info */ \ | |
| virtual address code_begin(Stub* self) const { return cast(self)->code_begin(); } \ | |
| virtual address code_end(Stub* self) const { return cast(self)->code_end(); } \ | |
| \ | |
| /* Debugging */ \ | |
| virtual void verify(Stub* self) { cast(self)->verify(); } \ | |
| virtual void print(Stub* self) { cast(self)->print(); } \ | |
| }; | |
| // A StubQueue maintains a queue of stubs. | |
| // Note: All sizes (spaces) are given in bytes. | |
| class StubQueue: public CHeapObj<mtCode> { | |
| friend class VMStructs; | |
| private: | |
| StubInterface* _stub_interface; // the interface prototype | |
| address _stub_buffer; // where all stubs are stored | |
| int _buffer_size; // the buffer size in bytes | |
| int _buffer_limit; // the (byte) index of the actual buffer limit (_buffer_limit <= _buffer_size) | |
| int _queue_begin; // the (byte) index of the first queue entry (word-aligned) | |
| int _queue_end; // the (byte) index of the first entry after the queue (word-aligned) | |
| int _number_of_stubs; // the number of buffered stubs | |
| Mutex* const _mutex; // the lock used for a (request, commit) transaction | |
| void check_index(int i) const { assert(0 <= i && i < _buffer_limit && i % stub_alignment() == 0, "illegal index"); } | |
| void check_stub_align(Stub* s) const { assert(((intptr_t)s) % stub_alignment() == 0, "incorrect stub alignment"); } | |
| bool is_contiguous() const { return _queue_begin <= _queue_end; } | |
| int index_of(Stub* s) const { int i = (int)((address)s - _stub_buffer); check_index(i); return i; } | |
| Stub* stub_at(int i) const { check_index(i); Stub* s = (Stub*)(_stub_buffer + i); check_stub_align(s); return s; } | |
| Stub* current_stub() const { return stub_at(_queue_end); } | |
| // Stub functionality accessed via interface | |
| void stub_initialize(Stub* s, int size) { assert(size % stub_alignment() == 0, "size not aligned"); _stub_interface->initialize(s, size); } | |
| void stub_finalize(Stub* s) { _stub_interface->finalize(s); } | |
| int stub_size(Stub* s) const { return _stub_interface->size(s); } | |
| bool stub_contains(Stub* s, address pc) const { return _stub_interface->code_begin(s) <= pc && pc < _stub_interface->code_end(s); } | |
| int stub_alignment() const { return _stub_interface->alignment(); } | |
| address stub_code_begin(Stub* s) const { return _stub_interface->code_begin(s); } | |
| void stub_verify(Stub* s) { _stub_interface->verify(s); } | |
| void stub_print(Stub* s) { _stub_interface->print(s); } | |
| // Helpers | |
| int compute_stub_size(Stub* stub, int code_size); | |
| public: | |
| StubQueue(StubInterface* stub_interface, int buffer_size, Mutex* lock, | |
| const char* name); | |
| ~StubQueue(); | |
| // General queue info | |
| bool is_empty() const { return _queue_begin == _queue_end; } | |
| int total_space() const { return _buffer_size - 1; } | |
| int available_space() const { int d = _queue_begin - _queue_end - 1; return d < 0 ? d + _buffer_size : d; } | |
| int used_space() const { return total_space() - available_space(); } | |
| int number_of_stubs() const { return _number_of_stubs; } | |
| bool contains(address pc) const { return _stub_buffer <= pc && pc < _stub_buffer + _buffer_limit; } | |
| Stub* stub_containing(address pc) const; | |
| address code_start() const { return _stub_buffer; } | |
| address code_end() const { return _stub_buffer + _buffer_limit; } | |
| // Stub allocation (atomic transactions) | |
| Stub* request_committed(int code_size); // request a stub that provides exactly code_size space for code | |
| Stub* request(int requested_code_size); // request a stub with a (maximum) code space - locks the queue | |
| void commit (int committed_code_size); // commit the previously requested stub - unlocks the queue | |
| // Stub deallocation | |
| void remove_first(); // remove the first stub in the queue | |
| void remove_first(int n); // remove the first n stubs in the queue | |
| void remove_all(); // remove all stubs in the queue | |
| void deallocate_unused_tail(); // deallocate the unused tail of the underlying CodeBlob | |
| // only used from TemplateInterpreter::initialize() | |
| // Iteration | |
| Stub* first() const { return number_of_stubs() > 0 ? stub_at(_queue_begin) : nullptr; } | |
| Stub* next(Stub* s) const { int i = index_of(s) + stub_size(s); | |
| // Only wrap around in the non-contiguous case (see stubss.cpp) | |
| if (i == _buffer_limit && _queue_end < _buffer_limit) i = 0; | |
| return (i == _queue_end) ? nullptr : stub_at(i); | |
| } | |
| // Debugging/printing | |
| void verify(); // verifies the stub queue | |
| void print(); // prints information about the stub queue | |
| }; | |
| #endif // SHARE_CODE_STUBS_HPP |