diff -r 2f5e556a6037 -r ae5c415036b0 hotspot/src/share/vm/runtime/jniHandles.hpp --- a/hotspot/src/share/vm/runtime/jniHandles.hpp Wed Feb 15 22:19:13 2017 -0500 +++ b/hotspot/src/share/vm/runtime/jniHandles.hpp Thu Feb 16 10:41:19 2017 -0800 @@ -1,5 +1,5 @@ /* - * Copyright (c) 1998, 2017, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 1998, 2014, 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 @@ -40,28 +40,7 @@ static JNIHandleBlock* _weak_global_handles; // First weak global handle block static oop _deleted_handle; // Sentinel marking deleted handles - inline static bool is_jweak(jobject handle); - inline static oop& jobject_ref(jobject handle); // NOT jweak! - inline static oop& jweak_ref(jobject handle); - - template inline static oop guard_value(oop value); - template inline static oop resolve_impl(jobject handle); - template static oop resolve_jweak(jweak handle); - public: - // Low tag bit in jobject used to distinguish a jweak. jweak is - // type equivalent to jobject, but there are places where we need to - // be able to distinguish jweak values from other jobjects, and - // is_weak_global_handle is unsuitable for performance reasons. To - // provide such a test we add weak_tag_value to the (aligned) byte - // address designated by the jobject to produce the corresponding - // jweak. Accessing the value of a jobject must account for it - // being a possibly offset jweak. - static const uintptr_t weak_tag_size = 1; - static const uintptr_t weak_tag_alignment = (1u << weak_tag_size); - static const uintptr_t weak_tag_mask = weak_tag_alignment - 1; - static const int weak_tag_value = 1; - // Resolve handle into oop inline static oop resolve(jobject handle); // Resolve externally provided handle into oop with some guards @@ -197,85 +176,36 @@ #endif }; -inline bool JNIHandles::is_jweak(jobject handle) { - STATIC_ASSERT(weak_tag_size == 1); - STATIC_ASSERT(weak_tag_value == 1); - return (reinterpret_cast(handle) & weak_tag_mask) != 0; -} - -inline oop& JNIHandles::jobject_ref(jobject handle) { - assert(!is_jweak(handle), "precondition"); - return *reinterpret_cast(handle); -} - -inline oop& JNIHandles::jweak_ref(jobject handle) { - assert(is_jweak(handle), "precondition"); - char* ptr = reinterpret_cast(handle) - weak_tag_value; - return *reinterpret_cast(ptr); -} - -// external_guard is true if called from resolve_external_guard. -// Treat deleted (and possibly zapped) as NULL for external_guard, -// else as (asserted) error. -template -inline oop JNIHandles::guard_value(oop value) { - if (!external_guard) { - assert(value != badJNIHandle, "Pointing to zapped jni handle area"); - assert(value != deleted_handle(), "Used a deleted global handle"); - } else if ((value == badJNIHandle) || (value == deleted_handle())) { - value = NULL; - } - return value; -} - -// external_guard is true if called from resolve_external_guard. -template -inline oop JNIHandles::resolve_impl(jobject handle) { - assert(handle != NULL, "precondition"); - oop result; - if (is_jweak(handle)) { // Unlikely - result = resolve_jweak(handle); - } else { - result = jobject_ref(handle); - // Construction of jobjects canonicalize a null value into a null - // jobject, so for non-jweak the pointee should never be null. - assert(external_guard || result != NULL, - "Invalid value read from jni handle"); - result = guard_value(result); - } - return result; -} inline oop JNIHandles::resolve(jobject handle) { - oop result = NULL; - if (handle != NULL) { - result = resolve_impl(handle); - } + oop result = (handle == NULL ? (oop)NULL : *(oop*)handle); + assert(result != NULL || (handle == NULL || !CheckJNICalls || is_weak_global_handle(handle)), "Invalid value read from jni handle"); + assert(result != badJNIHandle, "Pointing to zapped jni handle area"); return result; -} +}; + -// Resolve some erroneous cases to NULL, rather than treating them as -// possibly unchecked errors. In particular, deleted handles are -// treated as NULL (though a deleted and later reallocated handle -// isn't detected). inline oop JNIHandles::resolve_external_guard(jobject handle) { - oop result = NULL; - if (handle != NULL) { - result = resolve_impl(handle); - } + if (handle == NULL) return NULL; + oop result = *(oop*)handle; + if (result == NULL || result == badJNIHandle) return NULL; return result; -} +}; + inline oop JNIHandles::resolve_non_null(jobject handle) { assert(handle != NULL, "JNI handle should not be null"); - oop result = resolve_impl(handle); - assert(result != NULL, "NULL read from jni handle"); + oop result = *(oop*)handle; + assert(result != NULL, "Invalid value read from jni handle"); + assert(result != badJNIHandle, "Pointing to zapped jni handle area"); + // Don't let that private _deleted_handle object escape into the wild. + assert(result != deleted_handle(), "Used a deleted global handle."); return result; -} +}; inline void JNIHandles::destroy_local(jobject handle) { if (handle != NULL) { - jobject_ref(handle) = deleted_handle(); + *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it } }