view src/share/vm/oops/symbolOop.cpp @ 2149:7e37af9d69ef

7011379: G1: overly long concurrent marking cycles Summary: This changeset introduces filtering of SATB buffers at the point when they are about to be enqueued. If this filtering clears enough entries on each buffer, the buffer can then be re-used and not enqueued. This cuts down the number of SATB buffers that need to be processed by the concurrent marking threads. Reviewed-by: johnc, ysr
author tonyp
date Wed, 19 Jan 2011 09:35:17 -0500
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.
 *
 */

#include "precompiled.hpp"
#include "oops/oop.inline.hpp"
#include "oops/symbolOop.hpp"


// ------------------------------------------------------------------
// symbolOopDesc::equals
//
// Compares the symbol with a string of the given length.
bool symbolOopDesc::equals(const char* str, int len) const {
  int l = utf8_length();
  if (l != len) return false;
  while (l-- > 0) {
    if (str[l] != (char) byte_at(l))
      return false;
  }
  assert(l == -1, "we should be at the beginning");
  return true;
}


// ------------------------------------------------------------------
// symbolOopDesc::starts_with
//
// Tests if the symbol starts with the specified prefix of the given
// length.
bool symbolOopDesc::starts_with(const char* prefix, int len) const {
  if (len > utf8_length()) return false;
  while (len-- > 0) {
    if (prefix[len] != (char) byte_at(len))
      return false;
  }
  assert(len == -1, "we should be at the beginning");
  return true;
}


// ------------------------------------------------------------------
// symbolOopDesc::index_of
//
// Finds if the given string is a substring of this symbol's utf8 bytes.
// Return -1 on failure.  Otherwise return the first index where str occurs.
int symbolOopDesc::index_of_at(int i, const char* str, int len) const {
  assert(i >= 0 && i <= utf8_length(), "oob");
  if (len <= 0)  return 0;
  char first_char = str[0];
  address bytes = (address) ((symbolOopDesc*)this)->base();
  address limit = bytes + utf8_length() - len;  // inclusive limit
  address scan = bytes + i;
  if (scan > limit)
    return -1;
  for (;;) {
    scan = (address) memchr(scan, first_char, (limit + 1 - scan));
    if (scan == NULL)
      return -1;  // not found
    assert(scan >= bytes+i && scan <= limit, "scan oob");
    if (memcmp(scan, str, len) == 0)
      return (int)(scan - bytes);
  }
}


char* symbolOopDesc::as_C_string(char* buf, int size) const {
  if (size > 0) {
    int len = MIN2(size - 1, utf8_length());
    for (int i = 0; i < len; i++) {
      buf[i] = byte_at(i);
    }
    buf[len] = '\0';
  }
  return buf;
}

char* symbolOopDesc::as_C_string() const {
  int len = utf8_length();
  char* str = NEW_RESOURCE_ARRAY(char, len + 1);
  return as_C_string(str, len + 1);
}

char* symbolOopDesc::as_C_string_flexible_buffer(Thread* t,
                                                 char* buf, int size) const {
  char* str;
  int len = utf8_length();
  int buf_len = len + 1;
  if (size < buf_len) {
    str = NEW_RESOURCE_ARRAY(char, buf_len);
  } else {
    str = buf;
  }
  return as_C_string(str, buf_len);
}

void symbolOopDesc::print_symbol_on(outputStream* st) {
  st = st ? st : tty;
  int length = UTF8::unicode_length((const char*)bytes(), utf8_length());
  const char *ptr = (const char *)bytes();
  jchar value;
  for (int index = 0; index < length; index++) {
    ptr = UTF8::next(ptr, &value);
    if (value >= 32 && value < 127 || value == '\'' || value == '\\') {
      st->put(value);
    } else {
      st->print("\\u%04x", value);
    }
  }
}

jchar* symbolOopDesc::as_unicode(int& length) const {
  symbolOopDesc* this_ptr = (symbolOopDesc*)this;
  length = UTF8::unicode_length((char*)this_ptr->bytes(), utf8_length());
  jchar* result = NEW_RESOURCE_ARRAY(jchar, length);
  if (length > 0) {
    UTF8::convert_to_unicode((char*)this_ptr->bytes(), result, length);
  }
  return result;
}

const char* symbolOopDesc::as_klass_external_name(char* buf, int size) const {
  if (size > 0) {
    char* str    = as_C_string(buf, size);
    int   length = (int)strlen(str);
    // Turn all '/'s into '.'s (also for array klasses)
    for (int index = 0; index < length; index++) {
      if (str[index] == '/') {
        str[index] = '.';
      }
    }
    return str;
  } else {
    return buf;
  }
}

const char* symbolOopDesc::as_klass_external_name() const {
  char* str    = as_C_string();
  int   length = (int)strlen(str);
  // Turn all '/'s into '.'s (also for array klasses)
  for (int index = 0; index < length; index++) {
    if (str[index] == '/') {
      str[index] = '.';
    }
  }
  return str;
}