src/share/vm/prims/unsafe.cpp

rev 13113 : 8182487: Add Unsafe.objectFieldOffset(Class, String)
Reviewed-by: dsimms, twisti, bchristi, mgerdin

*** 25,34 ****
--- 25,35 ----
  #include "precompiled.hpp"
  #include "classfile/classFileStream.hpp"
  #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"
  #include "prims/jvm.h"
  #include "prims/unsafe.hpp"
*** 581,590 ****
--- 582,614 ----
  
  UNSAFE_LEAF(jint, Unsafe_PageSize()) {
    return os::vm_page_size();
  } UNSAFE_END
  
+ static jint 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 jint 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);
    oop mirror      = java_lang_reflect_Field::clazz(reflected);
*** 605,614 ****
--- 629,642 ----
  
  UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
    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
  
  UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) {
*** 710,727 ****
    return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
  } UNSAFE_END
  
  
  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);
    if (env->ExceptionCheck()) {
      env->ExceptionClear();
!     tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", buf);
      return;
    }
  
    env->ThrowNew(cls, NULL);
  }
--- 738,751 ----
    return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
  } UNSAFE_END
  
  
  static inline void throw_new(JNIEnv *env, const char *ename) {
!   jclass cls = env->FindClass(ename);
    if (env->ExceptionCheck()) {
      env->ExceptionClear();
!     tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename);
      return;
    }
  
    env->ThrowNew(cls, NULL);
  }
*** 741,751 ****
      ClassLoader::unsafe_defineClassCallCounter()->inc();
    }
  
    body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
    if (body == NULL) {
!     throw_new(env, "OutOfMemoryError");
      return 0;
    }
  
    env->GetByteArrayRegion(data, offset, length, body);
    if (env->ExceptionOccurred()) {
--- 765,775 ----
      ClassLoader::unsafe_defineClassCallCounter()->inc();
    }
  
    body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
    if (body == NULL) {
!     throw_new(env, "java/lang/OutOfMemoryError");
      return 0;
    }
  
    env->GetByteArrayRegion(data, offset, length, body);
    if (env->ExceptionOccurred()) {
*** 757,767 ****
      int unicode_len = env->GetStringLength(name);
  
      if (len >= sizeof(buf)) {
        utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
        if (utfName == NULL) {
!         throw_new(env, "OutOfMemoryError");
          goto free_body;
        }
      } else {
        utfName = buf;
      }
--- 781,791 ----
      int unicode_len = env->GetStringLength(name);
  
      if (len >= sizeof(buf)) {
        utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
        if (utfName == NULL) {
!         throw_new(env, "java/lang/OutOfMemoryError");
          goto free_body;
        }
      } else {
        utfName = buf;
      }
*** 1180,1189 ****
--- 1204,1214 ----
      {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)},
  
      {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)},
      {CC "arrayBaseOffset0",   CC "(" CLS ")I",           FN_PTR(Unsafe_ArrayBaseOffset0)},
      {CC "arrayIndexScale0",   CC "(" CLS ")I",           FN_PTR(Unsafe_ArrayIndexScale0)},