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8182487: Add Unsafe.objectFieldOffset(Class, String)

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Reviewed-by: dsimms, twisti, bchristi, mgerdin, psandoz, chegar
This commit is contained in:
Claes Redestad 2017-06-22 15:53:07 +02:00
parent 06cee886b1
commit 92c45050f9
1 changed files with 34 additions and 9 deletions
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43
hotspot/src/share/vm/prims/unsafe.cpp
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@ -27,6 +27,7 @@
#include "classfile/vmSymbols.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/resourceArea.hpp"
#include "oops/fieldStreams.hpp"
#include "oops/objArrayOop.inline.hpp"
#include "oops/oop.inline.hpp"
#include "prims/jni.h"
@ -583,7 +584,30 @@ UNSAFE_LEAF(jint, Unsafe_PageSize()) {
return os::vm_page_size();
} UNSAFE_END
static jint find_field_offset(jobject field, int must_be_static, TRAPS) {
static jlong find_field_offset(jclass clazz, jstring name, TRAPS) {
assert(clazz != NULL, "clazz must not be NULL");
assert(name != NULL, "name must not be NULL");
ResourceMark rm(THREAD);
char *utf_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name));
InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(clazz)));
jint offset = -1;
for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
Symbol *name = fs.name();
if (name->equals(utf_name)) {
offset = fs.offset();
break;
}
}
if (offset < 0) {
THROW_0(vmSymbols::java_lang_InternalError());
}
return field_offset_from_byte_offset(offset);
}
static jlong find_field_offset(jobject field, int must_be_static, TRAPS) {
assert(field != NULL, "field must not be NULL");
oop reflected = JNIHandles::resolve_non_null(field);
@ -607,6 +631,10 @@ UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobje
return find_field_offset(field, 0, THREAD);
} UNSAFE_END
UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset1(JNIEnv *env, jobject unsafe, jclass c, jstring name)) {
return find_field_offset(c, name, THREAD);
} UNSAFE_END
UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
return find_field_offset(field, 1, THREAD);
} UNSAFE_END
@ -712,14 +740,10 @@ UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass c
static inline void throw_new(JNIEnv *env, const char *ename) {
char buf[100];
jio_snprintf(buf, 100, "%s%s", "java/lang/", ename);
jclass cls = env->FindClass(buf);
jclass cls = env->FindClass(ename);
if (env->ExceptionCheck()) {
env->ExceptionClear();
tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", buf);
tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename);
return;
}
@ -743,7 +767,7 @@ static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data
body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
if (body == NULL) {
throw_new(env, "OutOfMemoryError");
throw_new(env, "java/lang/OutOfMemoryError");
return 0;
}
@ -759,7 +783,7 @@ static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data
if (len >= sizeof(buf)) {
utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
if (utfName == NULL) {
throw_new(env, "OutOfMemoryError");
throw_new(env, "java/lang/OutOfMemoryError");
goto free_body;
}
} else {
@ -1182,6 +1206,7 @@ static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
{CC "freeMemory0", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory0)},
{CC "objectFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset0)},
{CC "objectFieldOffset1", CC "(" CLS LANG "String;)J", FN_PTR(Unsafe_ObjectFieldOffset1)},
{CC "staticFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset0)},
{CC "staticFieldBase0", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBase0)},
{CC "ensureClassInitialized0", CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized0)},