Mercurial > hg > graal-jvmci-8
view src/share/vm/code/compressedStream.hpp @ 3979:4dfb2df418f2
6484982: G1: process references during evacuation pauses
Summary: G1 now uses two reference processors - one is used by concurrent marking and the other is used by STW GCs (both full and incremental evacuation pauses). In an evacuation pause, the reference processor is embedded into the closures used to scan objects. Doing so causes causes reference objects to be 'discovered' by the reference processor. At the end of the evacuation pause, these discovered reference objects are processed - preserving (and copying) referent objects (and their reachable graphs) as appropriate.
Reviewed-by: ysr, jwilhelm, brutisso, stefank, tonyp
author | johnc |
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date | Thu, 22 Sep 2011 10:57:37 -0700 |
parents | f95d63e2154a |
children |
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/* * Copyright (c) 1997, 2010, 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. * */ #ifndef SHARE_VM_CODE_COMPRESSEDSTREAM_HPP #define SHARE_VM_CODE_COMPRESSEDSTREAM_HPP #include "memory/allocation.hpp" // Simple interface for filing out and filing in basic types // Used for writing out and reading in debugging information. class CompressedStream : public ResourceObj { friend class VMStructs; protected: u_char* _buffer; int _position; enum { // Constants for UNSIGNED5 coding of Pack200 lg_H = 6, H = 1<<lg_H, // number of high codes (64) L = (1<<BitsPerByte)-H, // number of low codes (192) MAX_i = 4 // bytes are numbered in (0..4), max 5 bytes }; // these inlines are defined only in compressedStream.cpp static inline juint encode_sign(jint value); // for Pack200 SIGNED5 static inline jint decode_sign(juint value); // for Pack200 SIGNED5 static inline juint reverse_int(juint bits); // to trim trailing float 0's public: CompressedStream(u_char* buffer, int position = 0) { _buffer = buffer; _position = position; } u_char* buffer() const { return _buffer; } // Positioning int position() const { return _position; } void set_position(int position) { _position = position; } }; class CompressedReadStream : public CompressedStream { private: inline u_char read() { return _buffer[_position++]; } jint read_int_mb(jint b0); // UNSIGNED5 coding, 2-5 byte cases public: CompressedReadStream(u_char* buffer, int position = 0) : CompressedStream(buffer, position) {} jboolean read_bool() { return (jboolean) read(); } jbyte read_byte() { return (jbyte ) read(); } jchar read_char() { return (jchar ) read_int(); } jshort read_short() { return (jshort ) read_signed_int(); } jint read_int() { jint b0 = read(); if (b0 < L) return b0; else return read_int_mb(b0); } jint read_signed_int(); jfloat read_float(); // jfloat_cast(reverse_int(read_int())) jdouble read_double(); // jdouble_cast(2*reverse_int(read_int)) jlong read_long(); // jlong_from(2*read_signed_int()) }; class CompressedWriteStream : public CompressedStream { private: bool full() { return _position >= _size; } void store(u_char b) { _buffer[_position++] = b; } void write(u_char b) { if (full()) grow(); store(b); } void grow(); void write_int_mb(jint value); // UNSIGNED5 coding, 1-5 byte cases protected: int _size; public: CompressedWriteStream(int initial_size); CompressedWriteStream(u_char* buffer, int initial_size, int position = 0) : CompressedStream(buffer, position) { _size = initial_size; } void write_bool(jboolean value) { write(value); } void write_byte(jbyte value) { write(value); } void write_char(jchar value) { write_int(value); } void write_short(jshort value) { write_signed_int(value); } void write_int(jint value) { if ((juint)value < L && !full()) store((u_char)value); else write_int_mb(value); } void write_signed_int(jint value); // write_int(encode_sign(value)) void write_float(jfloat value); // write_int(reverse_int(jint_cast(v))) void write_double(jdouble value); // write_int(reverse_int(<low,high>)) void write_long(jlong value); // write_signed_int(<low,high>) }; #endif // SHARE_VM_CODE_COMPRESSEDSTREAM_HPP