Mercurial > hg > graal-jvmci-8
view src/share/vm/runtime/javaCalls.hpp @ 1716:be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
Summary: GC workers now recognize an intermediate transient state of blocks which are allocated but have not yet completed initialization. blk_start() calls do not attempt to determine the size of a block in the transient state, rather waiting for the block to become initialized so that it is safe to query its size. Audited and ensured the order of initialization of object fields (klass, free bit and size) to respect block state transition protocol. Also included some new assertion checking code enabled in debug mode.
Reviewed-by: chrisphi, johnc, poonam
author | ysr |
---|---|
date | Mon, 16 Aug 2010 15:58:42 -0700 |
parents | c18cbe5936b8 |
children | 2d26b0046e0d f95d63e2154a |
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/* * Copyright (c) 1997, 2008, 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 * or visit www.oracle.com if you need additional information or have any * questions. * */ // A JavaCallWrapper is constructed before each JavaCall and destructed after the call. // Its purpose is to allocate/deallocate a new handle block and to save/restore the last // Java fp/sp. A pointer to the JavaCallWrapper is stored on the stack. class JavaCallWrapper: StackObj { friend class VMStructs; private: JavaThread* _thread; // the thread to which this call belongs JNIHandleBlock* _handles; // the saved handle block methodOop _callee_method; // to be able to collect arguments if entry frame is top frame oop _receiver; // the receiver of the call (if a non-static call) JavaFrameAnchor _anchor; // last thread anchor state that we must restore JavaValue* _result; // result value public: // Construction/destruction JavaCallWrapper(methodHandle callee_method, Handle receiver, JavaValue* result, TRAPS); ~JavaCallWrapper(); // Accessors JavaThread* thread() const { return _thread; } JNIHandleBlock* handles() const { return _handles; } JavaFrameAnchor* anchor(void) { return &_anchor; } JavaValue* result() const { return _result; } // GC support methodOop callee_method() { return _callee_method; } oop receiver() { return _receiver; } void oops_do(OopClosure* f); }; // Encapsulates arguments to a JavaCall (faster, safer, and more convenient than using var-args) class JavaCallArguments : public StackObj { private: enum Constants { _default_size = 8 // Must be at least # of arguments in JavaCalls methods }; intptr_t _value_buffer [_default_size + 1]; bool _is_oop_buffer[_default_size + 1]; intptr_t* _value; bool* _is_oop; int _size; int _max_size; bool _start_at_zero; // Support late setting of receiver void initialize() { // Starts at first element to support set_receiver. _value = &_value_buffer[1]; _is_oop = &_is_oop_buffer[1]; _max_size = _default_size; _size = 0; _start_at_zero = false; } public: JavaCallArguments() { initialize(); } JavaCallArguments(Handle receiver) { initialize(); push_oop(receiver); } JavaCallArguments(int max_size) { if (max_size > _default_size) { _value = NEW_RESOURCE_ARRAY(intptr_t, max_size + 1); _is_oop = NEW_RESOURCE_ARRAY(bool, max_size + 1); // Reserve room for potential receiver in value and is_oop _value++; _is_oop++; _max_size = max_size; _size = 0; _start_at_zero = false; } else { initialize(); } } inline void push_oop(Handle h) { _is_oop[_size] = true; JNITypes::put_obj((oop)h.raw_value(), _value, _size); } inline void push_int(int i) { _is_oop[_size] = false; JNITypes::put_int(i, _value, _size); } inline void push_double(double d) { _is_oop[_size] = false; _is_oop[_size + 1] = false; JNITypes::put_double(d, _value, _size); } inline void push_long(jlong l) { _is_oop[_size] = false; _is_oop[_size + 1] = false; JNITypes::put_long(l, _value, _size); } inline void push_float(float f) { _is_oop[_size] = false; JNITypes::put_float(f, _value, _size); } // receiver Handle receiver() { assert(_size > 0, "must at least be one argument"); assert(_is_oop[0], "first argument must be an oop"); assert(_value[0] != 0, "receiver must be not-null"); return Handle((oop*)_value[0], false); } void set_receiver(Handle h) { assert(_start_at_zero == false, "can only be called once"); _start_at_zero = true; _is_oop--; _value--; _size++; _is_oop[0] = true; _value[0] = (intptr_t)h.raw_value(); } // Converts all Handles to oops, and returns a reference to parameter vector intptr_t* parameters() ; int size_of_parameters() const { return _size; } // Verify that pushed arguments fits a given method void verify(methodHandle method, BasicType return_type, Thread *thread); }; // All calls to Java have to go via JavaCalls. Sets up the stack frame // and makes sure that the last_Java_frame pointers are chained correctly. // class JavaCalls: AllStatic { static void call_helper(JavaValue* result, methodHandle* method, JavaCallArguments* args, TRAPS); public: // Optimized Constuctor call static void call_default_constructor(JavaThread* thread, methodHandle method, Handle receiver, TRAPS); // call_special // ------------ // The receiver must be first oop in argument list static void call_special(JavaValue* result, KlassHandle klass, symbolHandle name, symbolHandle signature, JavaCallArguments* args, TRAPS); static void call_special(JavaValue* result, Handle receiver, KlassHandle klass, symbolHandle name, symbolHandle signature, TRAPS); // No args static void call_special(JavaValue* result, Handle receiver, KlassHandle klass, symbolHandle name, symbolHandle signature, Handle arg1, TRAPS); static void call_special(JavaValue* result, Handle receiver, KlassHandle klass, symbolHandle name, symbolHandle signature, Handle arg1, Handle arg2, TRAPS); // virtual call // ------------ // The receiver must be first oop in argument list static void call_virtual(JavaValue* result, KlassHandle spec_klass, symbolHandle name, symbolHandle signature, JavaCallArguments* args, TRAPS); static void call_virtual(JavaValue* result, Handle receiver, KlassHandle spec_klass, symbolHandle name, symbolHandle signature, TRAPS); // No args static void call_virtual(JavaValue* result, Handle receiver, KlassHandle spec_klass, symbolHandle name, symbolHandle signature, Handle arg1, TRAPS); static void call_virtual(JavaValue* result, Handle receiver, KlassHandle spec_klass, symbolHandle name, symbolHandle signature, Handle arg1, Handle arg2, TRAPS); // Static call // ----------- static void call_static(JavaValue* result, KlassHandle klass, symbolHandle name, symbolHandle signature, JavaCallArguments* args, TRAPS); static void call_static(JavaValue* result, KlassHandle klass, symbolHandle name, symbolHandle signature, TRAPS); static void call_static(JavaValue* result, KlassHandle klass, symbolHandle name, symbolHandle signature, Handle arg1, TRAPS); static void call_static(JavaValue* result, KlassHandle klass, symbolHandle name, symbolHandle signature, Handle arg1, Handle arg2, TRAPS); // Low-level interface static void call(JavaValue* result, methodHandle method, JavaCallArguments* args, TRAPS); };