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6924259: Remove String.count/String.offset

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Allow a version of String class that doesn't have count and offset fields.

Reviewed-by: never, coleenp
This commit is contained in:
Vladimir Kozlov 2012-05-14 09:36:00 -07:00
parent 17b26a6a0c
commit eb4a860bc3
12 changed files with 365 additions and 191 deletions
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42
hotspot/src/share/vm/classfile/javaClasses.cpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2012, 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
@ -143,7 +143,27 @@ compute_optional_offset(int& dest_offset,
}
int java_lang_String::value_offset = 0;
int java_lang_String::offset_offset = 0;
int java_lang_String::count_offset = 0;
int java_lang_String::hash_offset = 0;
bool java_lang_String::initialized = false;
void java_lang_String::compute_offsets() {
assert(!initialized, "offsets should be initialized only once");
klassOop k = SystemDictionary::String_klass();
compute_offset(value_offset, k, vmSymbols::value_name(), vmSymbols::char_array_signature());
compute_optional_offset(offset_offset, k, vmSymbols::offset_name(), vmSymbols::int_signature());
compute_optional_offset(count_offset, k, vmSymbols::count_name(), vmSymbols::int_signature());
compute_optional_offset(hash_offset, k, vmSymbols::hash_name(), vmSymbols::int_signature());
initialized = true;
}
Handle java_lang_String::basic_create(int length, bool tenured, TRAPS) {
assert(initialized, "Must be initialized");
// Create the String object first, so there's a chance that the String
// and the char array it points to end up in the same cache line.
oop obj;
@ -2837,10 +2857,6 @@ int java_lang_System::err_offset_in_bytes() {
int java_lang_String::value_offset;
int java_lang_String::offset_offset;
int java_lang_String::count_offset;
int java_lang_String::hash_offset;
int java_lang_Class::_klass_offset;
int java_lang_Class::_array_klass_offset;
int java_lang_Class::_resolved_constructor_offset;
@ -3000,12 +3016,6 @@ void JavaClasses::compute_hard_coded_offsets() {
const int x = heapOopSize;
const int header = instanceOopDesc::base_offset_in_bytes();
// Do the String Class
java_lang_String::value_offset = java_lang_String::hc_value_offset * x + header;
java_lang_String::offset_offset = java_lang_String::hc_offset_offset * x + header;
java_lang_String::count_offset = java_lang_String::offset_offset + sizeof (jint);
java_lang_String::hash_offset = java_lang_String::count_offset + sizeof (jint);
// Throwable Class
java_lang_Throwable::backtrace_offset = java_lang_Throwable::hc_backtrace_offset * x + header;
java_lang_Throwable::detailMessage_offset = java_lang_Throwable::hc_detailMessage_offset * x + header;
@ -3200,9 +3210,13 @@ void JavaClasses::check_offsets() {
// java.lang.String
CHECK_OFFSET("java/lang/String", java_lang_String, value, "[C");
CHECK_OFFSET("java/lang/String", java_lang_String, offset, "I");
CHECK_OFFSET("java/lang/String", java_lang_String, count, "I");
CHECK_OFFSET("java/lang/String", java_lang_String, hash, "I");
if (java_lang_String::has_offset_field()) {
CHECK_OFFSET("java/lang/String", java_lang_String, offset, "I");
CHECK_OFFSET("java/lang/String", java_lang_String, count, "I");
}
if (java_lang_String::has_hash_field()) {
CHECK_OFFSET("java/lang/String", java_lang_String, hash, "I");
}
// java.lang.Class