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7009756: volatile variables could be broken throw reflection API

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Use Atomic::load() and Atomic::store() to access a volatile long.

Reviewed-by: iveresov, jrose, dholmes, never
This commit is contained in:
Vladimir Kozlov 2011-01-07 10:16:57 -08:00
parent 26ddf9c14a
commit afbf71368c
10 changed files with 154 additions and 62 deletions
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68
hotspot/src/share/vm/prims/unsafe.cpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2000, 2011, 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
@ -154,12 +154,11 @@ jint Unsafe_invocation_key_to_method_slot(jint key) {
#define GET_FIELD_VOLATILE(obj, offset, type_name, v) \
oop p = JNIHandles::resolve(obj); \
volatile type_name v = *(volatile type_name*)index_oop_from_field_offset_long(p, offset)
volatile type_name v = OrderAccess::load_acquire((volatile type_name*)index_oop_from_field_offset_long(p, offset));
#define SET_FIELD_VOLATILE(obj, offset, type_name, x) \
oop p = JNIHandles::resolve(obj); \
*(volatile type_name*)index_oop_from_field_offset_long(p, offset) = x; \
OrderAccess::fence();
OrderAccess::release_store_fence((volatile type_name*)index_oop_from_field_offset_long(p, offset), x);
// Macros for oops that check UseCompressedOops
@ -181,7 +180,8 @@ jint Unsafe_invocation_key_to_method_slot(jint key) {
v = oopDesc::decode_heap_oop(n); \
} else { \
v = *(volatile oop*)index_oop_from_field_offset_long(p, offset); \
}
} \
OrderAccess::acquire();
// Get/SetObject must be special-cased, since it works with handles.
@ -248,14 +248,22 @@ UNSAFE_ENTRY(void, Unsafe_SetObjectVolatile(JNIEnv *env, jobject unsafe, jobject
UnsafeWrapper("Unsafe_SetObjectVolatile");
oop x = JNIHandles::resolve(x_h);
oop p = JNIHandles::resolve(obj);
void* addr = index_oop_from_field_offset_long(p, offset);
OrderAccess::release();
if (UseCompressedOops) {
oop_store((narrowOop*)index_oop_from_field_offset_long(p, offset), x);
oop_store((narrowOop*)addr, x);
} else {
oop_store((oop*)index_oop_from_field_offset_long(p, offset), x);
oop_store((oop*)addr, x);
}
OrderAccess::fence();
UNSAFE_END
#if defined(SPARC) || defined(X86)
// Sparc and X86 have atomic jlong (8 bytes) instructions
#else
// Keep old code for platforms which may not have atomic jlong (8 bytes) instructions
// Volatile long versions must use locks if !VM_Version::supports_cx8().
// support_cx8 is a surrogate for 'supports atomic long memory ops'.
@ -291,6 +299,7 @@ UNSAFE_ENTRY(void, Unsafe_SetLongVolatile(JNIEnv *env, jobject unsafe, jobject o
}
UNSAFE_END
#endif // not SPARC and not X86
#define DEFINE_GETSETOOP(jboolean, Boolean) \
\
@ -320,6 +329,16 @@ UNSAFE_END \
\
// END DEFINE_GETSETOOP.
DEFINE_GETSETOOP(jboolean, Boolean)
DEFINE_GETSETOOP(jbyte, Byte)
DEFINE_GETSETOOP(jshort, Short);
DEFINE_GETSETOOP(jchar, Char);
DEFINE_GETSETOOP(jint, Int);
DEFINE_GETSETOOP(jlong, Long);
DEFINE_GETSETOOP(jfloat, Float);
DEFINE_GETSETOOP(jdouble, Double);
#undef DEFINE_GETSETOOP
#define DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean) \
\
@ -336,47 +355,49 @@ UNSAFE_END \
\
// END DEFINE_GETSETOOP_VOLATILE.
DEFINE_GETSETOOP(jboolean, Boolean)
DEFINE_GETSETOOP(jbyte, Byte)
DEFINE_GETSETOOP(jshort, Short);
DEFINE_GETSETOOP(jchar, Char);
DEFINE_GETSETOOP(jint, Int);
DEFINE_GETSETOOP(jlong, Long);
DEFINE_GETSETOOP(jfloat, Float);
DEFINE_GETSETOOP(jdouble, Double);
DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
DEFINE_GETSETOOP_VOLATILE(jshort, Short);
DEFINE_GETSETOOP_VOLATILE(jchar, Char);
DEFINE_GETSETOOP_VOLATILE(jint, Int);
// no long -- handled specially
DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
#undef DEFINE_GETSETOOP
#if defined(SPARC) || defined(X86)
// Sparc and X86 have atomic jlong (8 bytes) instructions
DEFINE_GETSETOOP_VOLATILE(jlong, Long);
#endif
#undef DEFINE_GETSETOOP_VOLATILE
// The non-intrinsified versions of setOrdered just use setVolatile
UNSAFE_ENTRY(void, Unsafe_SetOrderedInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint x)) \
UnsafeWrapper("Unsafe_SetOrderedInt"); \
SET_FIELD_VOLATILE(obj, offset, jint, x); \
UNSAFE_ENTRY(void, Unsafe_SetOrderedInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint x))
UnsafeWrapper("Unsafe_SetOrderedInt");
SET_FIELD_VOLATILE(obj, offset, jint, x);
UNSAFE_END
UNSAFE_ENTRY(void, Unsafe_SetOrderedObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h))
UnsafeWrapper("Unsafe_SetOrderedObject");
oop x = JNIHandles::resolve(x_h);
oop p = JNIHandles::resolve(obj);
void* addr = index_oop_from_field_offset_long(p, offset);
OrderAccess::release();
if (UseCompressedOops) {
oop_store((narrowOop*)index_oop_from_field_offset_long(p, offset), x);
oop_store((narrowOop*)addr, x);
} else {
oop_store((oop*)index_oop_from_field_offset_long(p, offset), x);
oop_store((oop*)addr, x);
}
OrderAccess::fence();
UNSAFE_END
UNSAFE_ENTRY(void, Unsafe_SetOrderedLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x))
UnsafeWrapper("Unsafe_SetOrderedLong");
#if defined(SPARC) || defined(X86)
// Sparc and X86 have atomic jlong (8 bytes) instructions
SET_FIELD_VOLATILE(obj, offset, jlong, x);
#else
// Keep old code for platforms which may not have atomic long (8 bytes) instructions
{
if (VM_Version::supports_cx8()) {
SET_FIELD_VOLATILE(obj, offset, jlong, x);
@ -388,6 +409,7 @@ UNSAFE_ENTRY(void, Unsafe_SetOrderedLong(JNIEnv *env, jobject unsafe, jobject ob
*addr = x;
}
}
#endif
UNSAFE_END
////// Data in the C heap.