--- old/src/share/vm/prims/unsafe.cpp 2016-05-03 11:37:49.825076368 -0700 +++ new/src/share/vm/prims/unsafe.cpp 2016-05-03 11:37:49.729074658 -0700 @@ -131,38 +131,140 @@ } -///// Data in the Java heap. +///// Data read/writes on the Java heap and in native (off-heap) memory -#define truncate_jboolean(x) ((x) & 1) -#define truncate_jbyte(x) (x) -#define truncate_jshort(x) (x) -#define truncate_jchar(x) (x) -#define truncate_jint(x) (x) -#define truncate_jlong(x) (x) -#define truncate_jfloat(x) (x) -#define truncate_jdouble(x) (x) - -#define GET_FIELD(obj, offset, type_name, v) \ - oop p = JNIHandles::resolve(obj); \ - type_name v = *(type_name*)index_oop_from_field_offset_long(p, offset) - -#define SET_FIELD(obj, offset, type_name, x) \ - oop p = JNIHandles::resolve(obj); \ - *(type_name*)index_oop_from_field_offset_long(p, offset) = truncate_##type_name(x) - -#define GET_FIELD_VOLATILE(obj, offset, type_name, v) \ - oop p = JNIHandles::resolve(obj); \ - if (support_IRIW_for_not_multiple_copy_atomic_cpu) { \ - OrderAccess::fence(); \ - } \ - 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); \ - OrderAccess::release_store_fence((volatile type_name*)index_oop_from_field_offset_long(p, offset), truncate_##type_name(x)); +/** + * Helper class for accessing memory. + * + * Normalizes values and wraps accesses in + * JavaThread::doing_unsafe_access() if needed. + */ +class MemoryAccess : StackObj { + JavaThread* _thread; + jobject _obj; + jlong _offset; + + // Resolves and returns the address of the memory access + void* addr() { + return index_oop_from_field_offset_long(JNIHandles::resolve(_obj), _offset); + } + + template + T normalize(T x) { + return x; + } + + jboolean normalize(jboolean x) { + return x & 1; + } + + /** + * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access() + */ + class GuardUnsafeAccess { + JavaThread* _thread; + bool _active; + + public: + GuardUnsafeAccess(JavaThread* thread, jobject _obj) : _thread(thread) { + if (JNIHandles::resolve(_obj) == NULL) { + // native/off-heap access which may raise SIGBUS if accessing + // memory mapped file data in a region of the file which has + // been truncated and is now invalid + _thread->set_doing_unsafe_access(true); + _active = true; + } else { + _active = false; + } + } + + ~GuardUnsafeAccess() { + if (_active) { + _thread->set_doing_unsafe_access(false); + } + } + }; + +public: + MemoryAccess(JavaThread* thread, jobject obj, jlong offset) + : _thread(thread), _obj(obj), _offset(offset) { + } + + template + T get() { + GuardUnsafeAccess guard(_thread, _obj); + + T* p = (T*)addr(); + + T x = *p; + + return x; + } + + template + void put(T x) { + GuardUnsafeAccess guard(_thread, _obj); + + T* p = (T*)addr(); + + *p = normalize(x); + } + + + template + T get_volatile() { + GuardUnsafeAccess guard(_thread, _obj); + + T* p = (T*)addr(); + + if (support_IRIW_for_not_multiple_copy_atomic_cpu) { + OrderAccess::fence(); + } + T x = OrderAccess::load_acquire((volatile T*)p); -// Get/SetObject must be special-cased, since it works with handles. + return x; + } + + template + void put_volatile(T x) { + GuardUnsafeAccess guard(_thread, _obj); + + T* p = (T*)addr(); + + OrderAccess::release_store_fence((volatile T*)p, normalize(x)); + } + + +#ifndef SUPPORTS_NATIVE_CX8 + // + template + T get_mutex() { + GuardUnsafeAccess guard(_thread, _obj); + + MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag); + + T* p = (T*)addr(); + + T x = Atomic::load(p); + + return x; + } + + template + void put_mutex(T x) { + GuardUnsafeAccess guard(_thread, _obj); + + MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag); + + T* p = (T*)addr(); + + Atomic::store(normalize(x), p); + } +#endif +}; + +// Get/PutObject must be special-cased, since it works with handles. // These functions allow a null base pointer with an arbitrary address. // But if the base pointer is non-null, the offset should make some sense. @@ -208,7 +310,7 @@ return ret; } UNSAFE_END -UNSAFE_ENTRY(void, Unsafe_SetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) { +UNSAFE_ENTRY(void, Unsafe_PutObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) { oop x = JNIHandles::resolve(x_h); oop p = JNIHandles::resolve(obj); @@ -236,7 +338,7 @@ return JNIHandles::make_local(env, v); } UNSAFE_END -UNSAFE_ENTRY(void, Unsafe_SetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) { +UNSAFE_ENTRY(void, Unsafe_PutObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) { oop x = JNIHandles::resolve(x_h); oop p = JNIHandles::resolve(obj); void* addr = index_oop_from_field_offset_long(p, offset); @@ -301,25 +403,17 @@ UNSAFE_ENTRY(jlong, Unsafe_GetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { if (VM_Version::supports_cx8()) { - GET_FIELD_VOLATILE(obj, offset, jlong, v); - return v; + return MemoryAccess(thread, obj, offset).get_volatile(); } else { - Handle p (THREAD, JNIHandles::resolve(obj)); - jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset)); - MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag); - jlong value = Atomic::load(addr); - return value; + return MemoryAccess(thread, obj, offset).get_mutex(); } } UNSAFE_END -UNSAFE_ENTRY(void, Unsafe_SetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x)) { +UNSAFE_ENTRY(void, Unsafe_PutLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x)) { if (VM_Version::supports_cx8()) { - SET_FIELD_VOLATILE(obj, offset, jlong, x); + MemoryAccess(thread, obj, offset).put_volatile(x); } else { - Handle p (THREAD, JNIHandles::resolve(obj)); - jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset)); - MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag); - Atomic::store(x, addr); + MemoryAccess(thread, obj, offset).put_mutex(x); } } UNSAFE_END @@ -337,15 +431,14 @@ return UseUnalignedAccesses; } UNSAFE_END -#define DEFINE_GETSETOOP(java_type, Type) \ +#define DEFINE_GETSETOOP(java_type, Type) \ \ UNSAFE_ENTRY(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \ - GET_FIELD(obj, offset, java_type, v); \ - return v; \ + return MemoryAccess(thread, obj, offset).get(); \ } UNSAFE_END \ \ -UNSAFE_ENTRY(void, Unsafe_Set##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \ - SET_FIELD(obj, offset, java_type, x); \ +UNSAFE_ENTRY(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \ + MemoryAccess(thread, obj, offset).put(x); \ } UNSAFE_END \ \ // END DEFINE_GETSETOOP. @@ -364,12 +457,11 @@ #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \ \ UNSAFE_ENTRY(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \ - GET_FIELD_VOLATILE(obj, offset, java_type, v); \ - return v; \ + return MemoryAccess(thread, obj, offset).get_volatile(); \ } UNSAFE_END \ \ -UNSAFE_ENTRY(void, Unsafe_Set##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \ - SET_FIELD_VOLATILE(obj, offset, java_type, x); \ +UNSAFE_ENTRY(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \ + MemoryAccess(thread, obj, offset).put_volatile(x); \ } UNSAFE_END \ \ // END DEFINE_GETSETOOP_VOLATILE. @@ -400,98 +492,6 @@ OrderAccess::fence(); } UNSAFE_END -////// Data in the C heap. - -// Note: These do not throw NullPointerException for bad pointers. -// They just crash. Only a oop base pointer can generate a NullPointerException. -// -#define DEFINE_GETSETNATIVE(java_type, Type, native_type) \ - \ -UNSAFE_ENTRY(java_type, Unsafe_GetNative##Type(JNIEnv *env, jobject unsafe, jlong addr)) { \ - void* p = addr_from_java(addr); \ - JavaThread* t = JavaThread::current(); \ - t->set_doing_unsafe_access(true); \ - java_type x = *(volatile native_type*)p; \ - t->set_doing_unsafe_access(false); \ - return x; \ -} UNSAFE_END \ - \ -UNSAFE_ENTRY(void, Unsafe_SetNative##Type(JNIEnv *env, jobject unsafe, jlong addr, java_type x)) { \ - JavaThread* t = JavaThread::current(); \ - t->set_doing_unsafe_access(true); \ - void* p = addr_from_java(addr); \ - *(volatile native_type*)p = x; \ - t->set_doing_unsafe_access(false); \ -} UNSAFE_END \ - \ -// END DEFINE_GETSETNATIVE. - -DEFINE_GETSETNATIVE(jbyte, Byte, signed char) -DEFINE_GETSETNATIVE(jshort, Short, signed short); -DEFINE_GETSETNATIVE(jchar, Char, unsigned short); -DEFINE_GETSETNATIVE(jint, Int, jint); -// no long -- handled specially -DEFINE_GETSETNATIVE(jfloat, Float, float); -DEFINE_GETSETNATIVE(jdouble, Double, double); - -#undef DEFINE_GETSETNATIVE - -UNSAFE_ENTRY(jlong, Unsafe_GetNativeLong(JNIEnv *env, jobject unsafe, jlong addr)) { - JavaThread* t = JavaThread::current(); - // We do it this way to avoid problems with access to heap using 64 - // bit loads, as jlong in heap could be not 64-bit aligned, and on - // some CPUs (SPARC) it leads to SIGBUS. - t->set_doing_unsafe_access(true); - void* p = addr_from_java(addr); - jlong x; - - if (is_ptr_aligned(p, sizeof(jlong)) == 0) { - // jlong is aligned, do a volatile access - x = *(volatile jlong*)p; - } else { - jlong_accessor acc; - acc.words[0] = ((volatile jint*)p)[0]; - acc.words[1] = ((volatile jint*)p)[1]; - x = acc.long_value; - } - - t->set_doing_unsafe_access(false); - - return x; -} UNSAFE_END - -UNSAFE_ENTRY(void, Unsafe_SetNativeLong(JNIEnv *env, jobject unsafe, jlong addr, jlong x)) { - JavaThread* t = JavaThread::current(); - // see comment for Unsafe_GetNativeLong - t->set_doing_unsafe_access(true); - void* p = addr_from_java(addr); - - if (is_ptr_aligned(p, sizeof(jlong))) { - // jlong is aligned, do a volatile access - *(volatile jlong*)p = x; - } else { - jlong_accessor acc; - acc.long_value = x; - ((volatile jint*)p)[0] = acc.words[0]; - ((volatile jint*)p)[1] = acc.words[1]; - } - - t->set_doing_unsafe_access(false); -} UNSAFE_END - - -UNSAFE_LEAF(jlong, Unsafe_GetNativeAddress(JNIEnv *env, jobject unsafe, jlong addr)) { - void* p = addr_from_java(addr); - - return addr_to_java(*(void**)p); -} UNSAFE_END - -UNSAFE_LEAF(void, Unsafe_SetNativeAddress(JNIEnv *env, jobject unsafe, jlong addr, jlong x)) { - void* p = addr_from_java(addr); - *(void**)p = addr_from_java(x); -} UNSAFE_END - - ////// Allocation requests UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) { @@ -980,8 +980,8 @@ } UNSAFE_END UNSAFE_ENTRY(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) { - Handle p (THREAD, JNIHandles::resolve(obj)); - jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset)); + Handle p(THREAD, JNIHandles::resolve(obj)); + jlong* addr = (jlong*)index_oop_from_field_offset_long(p(), offset); #ifdef SUPPORTS_NATIVE_CX8 return (jlong)(Atomic::cmpxchg(x, addr, e)); @@ -1017,7 +1017,7 @@ UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) { oop p = JNIHandles::resolve(obj); - jint* addr = (jint *) index_oop_from_field_offset_long(p, offset); + jint* addr = (jint *)index_oop_from_field_offset_long(p, offset); return (jint)(Atomic::cmpxchg(x, addr, e)) == e; } UNSAFE_END @@ -1143,20 +1143,16 @@ #define DECLARE_GETPUTOOP(Type, Desc) \ {CC "get" #Type, CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type)}, \ - {CC "put" #Type, CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Set##Type)}, \ + {CC "put" #Type, CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type)}, \ {CC "get" #Type "Volatile", CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type##Volatile)}, \ - {CC "put" #Type "Volatile", CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Set##Type##Volatile)} - + {CC "put" #Type "Volatile", CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type##Volatile)} -#define DECLARE_GETPUTNATIVE(Byte, B) \ - {CC "get" #Byte, CC "(" ADR ")" #B, FN_PTR(Unsafe_GetNative##Byte)}, \ - {CC "put" #Byte, CC "(" ADR#B ")V", FN_PTR(Unsafe_SetNative##Byte)} static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = { {CC "getObject", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObject)}, - {CC "putObject", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_SetObject)}, + {CC "putObject", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutObject)}, {CC "getObjectVolatile",CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObjectVolatile)}, - {CC "putObjectVolatile",CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_SetObjectVolatile)}, + {CC "putObjectVolatile",CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutObjectVolatile)}, {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)}, {CC "getJavaMirror", CC "(" ADR ")" CLS, FN_PTR(Unsafe_GetJavaMirror)}, @@ -1171,17 +1167,6 @@ DECLARE_GETPUTOOP(Float, F), DECLARE_GETPUTOOP(Double, D), - DECLARE_GETPUTNATIVE(Byte, B), - DECLARE_GETPUTNATIVE(Short, S), - DECLARE_GETPUTNATIVE(Char, C), - DECLARE_GETPUTNATIVE(Int, I), - DECLARE_GETPUTNATIVE(Long, J), - DECLARE_GETPUTNATIVE(Float, F), - DECLARE_GETPUTNATIVE(Double, D), - - {CC "getAddress", CC "(" ADR ")" ADR, FN_PTR(Unsafe_GetNativeAddress)}, - {CC "putAddress", CC "(" ADR "" ADR ")V", FN_PTR(Unsafe_SetNativeAddress)}, - {CC "allocateMemory0", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory0)}, {CC "reallocateMemory0", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory0)}, {CC "freeMemory0", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory0)}, @@ -1239,7 +1224,6 @@ #undef DAC_Args #undef DECLARE_GETPUTOOP -#undef DECLARE_GETPUTNATIVE // This function is exported, used by NativeLookup.