text: /*
   * Copyright (c) 1997, 2013, 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
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   *
   */
  
  #include "precompiled.hpp"
  #include "classfile/systemDictionary.hpp"
  #include "classfile/vmSymbols.hpp"
  #include "code/nmethod.hpp"
  #include "compiler/compileBroker.hpp"
  #include "interpreter/interpreter.hpp"
  #include "interpreter/linkResolver.hpp"
  #include "memory/universe.inline.hpp"
  #include "oops/oop.inline.hpp"
  #include "prims/jniCheck.hpp"
  #include "runtime/compilationPolicy.hpp"
  #include "runtime/handles.inline.hpp"
  #include "runtime/interfaceSupport.hpp"
  #include "runtime/javaCalls.hpp"
  #include "runtime/mutexLocker.hpp"
  #include "runtime/signature.hpp"
  #include "runtime/stubRoutines.hpp"
  #include "runtime/thread.inline.hpp"
  
  // -----------------------------------------------------
  // Implementation of JavaCallWrapper
  
  JavaCallWrapper::JavaCallWrapper(methodHandle callee_method, Handle receiver, JavaValue* result, TRAPS) {
    JavaThread* thread = (JavaThread *)THREAD;
    bool clear_pending_exception = true;
  
    guarantee(thread->is_Java_thread(), "crucial check - the VM thread cannot and must not escape to Java code");
    assert(!thread->owns_locks(), "must release all locks when leaving VM");
    guarantee(!thread->is_Compiler_thread(), "cannot make java calls from the compiler");
    _result   = result;
  
    // Allocate handle block for Java code. This must be done before we change thread_state to _thread_in_Java_or_stub,
    // since it can potentially block.
    JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(thread);
  
    // After this, we are official in JavaCode. This needs to be done before we change any of the thread local
    // info, since we cannot find oops before the new information is set up completely.
    ThreadStateTransition::transition(thread, _thread_in_vm, _thread_in_Java);
  
    // Make sure that we handle asynchronous stops and suspends _before_ we clear all thread state
    // in JavaCallWrapper::JavaCallWrapper(). This way, we can decide if we need to do any pd actions
    // to prepare for stop/suspend (flush register windows on sparcs, cache sp, or other state).
    if (thread->has_special_runtime_exit_condition()) {
      thread->handle_special_runtime_exit_condition();
      if (HAS_PENDING_EXCEPTION) {
        clear_pending_exception = false;
      }
    }
  
  
    // Make sure to set the oop's after the thread transition - since we can block there. No one is GC'ing
    // the JavaCallWrapper before the entry frame is on the stack.
    _callee_method = callee_method();
    _receiver = receiver();
  
  #ifdef CHECK_UNHANDLED_OOPS
    THREAD->allow_unhandled_oop(&_receiver);
  #endif // CHECK_UNHANDLED_OOPS
  
    _thread       = (JavaThread *)thread;
    _handles      = _thread->active_handles();    // save previous handle block & Java frame linkage
  
    // For the profiler, the last_Java_frame information in thread must always be in
    // legal state. We have no last Java frame if last_Java_sp == NULL so
    // the valid transition is to clear _last_Java_sp and then reset the rest of
    // the (platform specific) state.
  
    _anchor.copy(_thread->frame_anchor());
    _thread->frame_anchor()->clear();
  
    debug_only(_thread->inc_java_call_counter());
    _thread->set_active_handles(new_handles);     // install new handle block and reset Java frame linkage
  
    assert (_thread->thread_state() != _thread_in_native, "cannot set native pc to NULL");
  
    // clear any pending exception in thread (native calls start with no exception pending)
    if(clear_pending_exception) {
      _thread->clear_pending_exception();
    }
  
    if (_anchor.last_Java_sp() == NULL) {
      _thread->record_base_of_stack_pointer();
    }
  }
  
  
  JavaCallWrapper::~JavaCallWrapper() {
    assert(_thread == JavaThread::current(), "must still be the same thread");
  
    // restore previous handle block & Java frame linkage
    JNIHandleBlock *_old_handles = _thread->active_handles();
    _thread->set_active_handles(_handles);
  
    _thread->frame_anchor()->zap();
  
    debug_only(_thread->dec_java_call_counter());
  
    if (_anchor.last_Java_sp() == NULL) {
      _thread->set_base_of_stack_pointer(NULL);
    }
  
  
    // Old thread-local info. has been restored. We are not back in the VM.
    ThreadStateTransition::transition_from_java(_thread, _thread_in_vm);
  
    // State has been restored now make the anchor frame visible for the profiler.
    // Do this after the transition because this allows us to put an assert
    // the Java->vm transition which checks to see that stack is not walkable
    // on sparc/ia64 which will catch violations of the reseting of last_Java_frame
    // invariants (i.e. _flags always cleared on return to Java)
  
    _thread->frame_anchor()->copy(&_anchor);
  
    // Release handles after we are marked as being inside the VM again, since this
    // operation might block
    JNIHandleBlock::release_block(_old_handles, _thread);
  }
  
  
  void JavaCallWrapper::oops_do(OopClosure* f) {
    f->do_oop((oop*)&_receiver);
    handles()->oops_do(f);
  }
  
  
  // Helper methods
  static BasicType runtime_type_from(JavaValue* result) {
    switch (result->get_type()) {
      case T_BOOLEAN: // fall through
      case T_CHAR   : // fall through
      case T_SHORT  : // fall through
      case T_INT    : // fall through
  #ifndef _LP64
      case T_OBJECT : // fall through
      case T_ARRAY  : // fall through
  #endif
      case T_BYTE   : // fall through
      case T_VOID   : return T_INT;
      case T_LONG   : return T_LONG;
      case T_FLOAT  : return T_FLOAT;
      case T_DOUBLE : return T_DOUBLE;
  #ifdef _LP64
      case T_ARRAY  : // fall through
      case T_OBJECT:  return T_OBJECT;
  #endif
    }
    ShouldNotReachHere();
    return T_ILLEGAL;
  }
  
  // ===== object constructor calls =====
  
  void JavaCalls::call_default_constructor(JavaThread* thread, methodHandle method, Handle receiver, TRAPS) {
    assert(method->name() == vmSymbols::object_initializer_name(),    "Should only be called for default constructor");
    assert(method->signature() == vmSymbols::void_method_signature(), "Should only be called for default constructor");
  
    InstanceKlass* ik = method->method_holder();
    if (ik->is_initialized() && ik->has_vanilla_constructor()) {
      // safe to skip constructor call
    } else {
      static JavaValue result(T_VOID);
      JavaCallArguments args(receiver);
      call(&result, method, &args, CHECK);
    }
  }
  
  // ============ Virtual calls ============
  
  void JavaCalls::call_virtual(JavaValue* result, KlassHandle spec_klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS) {
    CallInfo callinfo;
    Handle receiver = args->receiver();
    KlassHandle recvrKlass(THREAD, receiver.is_null() ? (Klass*)NULL : receiver->klass());
    LinkResolver::resolve_virtual_call(
            callinfo, receiver, recvrKlass, spec_klass, name, signature,
            KlassHandle(), false, true, CHECK);
    methodHandle method = callinfo.selected_method();
    assert(method.not_null(), "should have thrown exception");
  
    // Invoke the method
    JavaCalls::call(result, method, args, CHECK);
  }
  
  
  void JavaCalls::call_virtual(JavaValue* result, Handle receiver, KlassHandle spec_klass, Symbol* name, Symbol* signature, TRAPS) {
    JavaCallArguments args(receiver); // One oop argument
    call_virtual(result, spec_klass, name, signature, &args, CHECK);
  }
  
  
  void JavaCalls::call_virtual(JavaValue* result, Handle receiver, KlassHandle spec_klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS) {
    JavaCallArguments args(receiver); // One oop argument
    args.push_oop(arg1);
    call_virtual(result, spec_klass, name, signature, &args, CHECK);
  }
  
  
  
  void JavaCalls::call_virtual(JavaValue* result, Handle receiver, KlassHandle spec_klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS) {
    JavaCallArguments args(receiver); // One oop argument
    args.push_oop(arg1);
    args.push_oop(arg2);
    call_virtual(result, spec_klass, name, signature, &args, CHECK);
  }
  
  
  // ============ Special calls ============
  
  void JavaCalls::call_special(JavaValue* result, KlassHandle klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS) {
    CallInfo callinfo;
    LinkResolver::resolve_special_call(callinfo, klass, name, signature, KlassHandle(), false, CHECK);
    methodHandle method = callinfo.selected_method();
    assert(method.not_null(), "should have thrown exception");
  
    // Invoke the method
    JavaCalls::call(result, method, args, CHECK);
  }
  
  
  void JavaCalls::call_special(JavaValue* result, Handle receiver, KlassHandle klass, Symbol* name, Symbol* signature, TRAPS) {
    JavaCallArguments args(receiver); // One oop argument
    call_special(result, klass, name, signature, &args, CHECK);
  }
  
  
  void JavaCalls::call_special(JavaValue* result, Handle receiver, KlassHandle klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS) {
    JavaCallArguments args(receiver); // One oop argument
    args.push_oop(arg1);
    call_special(result, klass, name, signature, &args, CHECK);
  }
  
  
  void JavaCalls::call_special(JavaValue* result, Handle receiver, KlassHandle klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS) {
    JavaCallArguments args(receiver); // One oop argument
    args.push_oop(arg1);
    args.push_oop(arg2);
    call_special(result, klass, name, signature, &args, CHECK);
  }
  
  
  // ============ Static calls ============
  
  void JavaCalls::call_static(JavaValue* result, KlassHandle klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS) {
    CallInfo callinfo;
    LinkResolver::resolve_static_call(callinfo, klass, name, signature, KlassHandle(), false, true, CHECK);
    methodHandle method = callinfo.selected_method();
    assert(method.not_null(), "should have thrown exception");
  
    // Invoke the method
    JavaCalls::call(result, method, args, CHECK);
  }
  
  
  void JavaCalls::call_static(JavaValue* result, KlassHandle klass, Symbol* name, Symbol* signature, TRAPS) {
    JavaCallArguments args; // No argument
    call_static(result, klass, name, signature, &args, CHECK);
  }
  
  
  void JavaCalls::call_static(JavaValue* result, KlassHandle klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS) {
    JavaCallArguments args(arg1); // One oop argument
    call_static(result, klass, name, signature, &args, CHECK);
  }
  
  
  void JavaCalls::call_static(JavaValue* result, KlassHandle klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS) {
    JavaCallArguments args; // One oop argument
    args.push_oop(arg1);
    args.push_oop(arg2);
    call_static(result, klass, name, signature, &args, CHECK);
  }
  
  
  // -------------------------------------------------
  // Implementation of JavaCalls (low level)
  
  
  void JavaCalls::call(JavaValue* result, methodHandle method, JavaCallArguments* args, TRAPS) {
    // Check if we need to wrap a potential OS exception handler around thread
    // This is used for e.g. Win32 structured exception handlers
    assert(THREAD->is_Java_thread(), "only JavaThreads can make JavaCalls");
    // Need to wrap each and everytime, since there might be native code down the
    // stack that has installed its own exception handlers
    os::os_exception_wrapper(call_helper, result, &method, args, THREAD);
  }
  
  void JavaCalls::call_helper(JavaValue* result, methodHandle* m, JavaCallArguments* args, TRAPS) {
    methodHandle method = *m;
    JavaThread* thread = (JavaThread*)THREAD;
    assert(thread->is_Java_thread(), "must be called by a java thread");
    assert(method.not_null(), "must have a method to call");
    assert(!SafepointSynchronize::is_at_safepoint(), "call to Java code during VM operation");
    assert(!thread->handle_area()->no_handle_mark_active(), "cannot call out to Java here");
  
  
    CHECK_UNHANDLED_OOPS_ONLY(thread->clear_unhandled_oops();)
  
    // Verify the arguments
  
    if (CheckJNICalls)  {
      args->verify(method, result->get_type(), thread);
    }
    else debug_only(args->verify(method, result->get_type(), thread));
  
    // Ignore call if method is empty
    if (method->is_empty_method()) {
      assert(result->get_type() == T_VOID, "an empty method must return a void value");
      return;
    }
  
  
  #ifdef ASSERT
    { InstanceKlass* holder = method->method_holder();
      // A klass might not be initialized since JavaCall's might be used during the executing of
      // the <clinit>. For example, a Thread.start might start executing on an object that is
      // not fully initialized! (bad Java programming style)
      assert(holder->is_linked(), "rewritting must have taken place");
    }
  #endif
  
  
    assert(!thread->is_Compiler_thread(), "cannot compile from the compiler");
    if (CompilationPolicy::must_be_compiled(method)) {
      CompileBroker::compile_method(method, InvocationEntryBci,
                                    CompilationPolicy::policy()->initial_compile_level(),
                                    methodHandle(), 0, "must_be_compiled", CHECK);
    }
  
    // Since the call stub sets up like the interpreter we call the from_interpreted_entry
    // so we can go compiled via a i2c. Otherwise initial entry method will always
    // run interpreted.
    address entry_point = method->from_interpreted_entry();
    if (JvmtiExport::can_post_interpreter_events() && thread->is_interp_only_mode()) {
      entry_point = method->interpreter_entry();
    }
  
    // Figure out if the result value is an oop or not (Note: This is a different value
    // than result_type. result_type will be T_INT of oops. (it is about size)
    BasicType result_type = runtime_type_from(result);
    bool oop_result_flag = (result->get_type() == T_OBJECT || result->get_type() == T_ARRAY);
  
    // NOTE: if we move the computation of the result_val_address inside
    // the call to call_stub, the optimizer produces wrong code.
    intptr_t* result_val_address = (intptr_t*)(result->get_value_addr());
  
    // Find receiver
    Handle receiver = (!method->is_static()) ? args->receiver() : Handle();
  
    // When we reenter Java, we need to reenable the yellow zone which
    // might already be disabled when we are in VM.
    if (thread->stack_yellow_zone_disabled()) {
      thread->reguard_stack();
    }
  
    // Check that there are shadow pages available before changing thread state
    // to Java
    if (!os::stack_shadow_pages_available(THREAD, method)) {
      // Throw stack overflow exception with preinitialized exception.
      Exceptions::throw_stack_overflow_exception(THREAD, __FILE__, __LINE__, method);
      return;
    } else {
      // Touch pages checked if the OS needs them to be touched to be mapped.
      os::bang_stack_shadow_pages();
    }
  
    // do call
    { JavaCallWrapper link(method, receiver, result, CHECK);
      { HandleMark hm(thread);  // HandleMark used by HandleMarkCleaner
  
        StubRoutines::call_stub()(
          (address)&link,
          // (intptr_t*)&(result->_value), // see NOTE above (compiler problem)
          result_val_address,          // see NOTE above (compiler problem)
          result_type,
          method(),
          entry_point,
          args->parameters(),
          args->size_of_parameters(),
          CHECK
        );
  
        result = link.result();  // circumvent MS C++ 5.0 compiler bug (result is clobbered across call)
        // Preserve oop return value across possible gc points
        if (oop_result_flag) {
          thread->set_vm_result((oop) result->get_jobject());
        }
      }
    } // Exit JavaCallWrapper (can block - potential return oop must be preserved)
  
    // Check if a thread stop or suspend should be executed
    // The following assert was not realistic.  Thread.stop can set that bit at any moment.
    //assert(!thread->has_special_runtime_exit_condition(), "no async. exceptions should be installed");
  
    // Restore possible oop return
    if (oop_result_flag) {
      result->set_jobject((jobject)thread->vm_result());
      thread->set_vm_result(NULL);
    }
  }
  
  
  //--------------------------------------------------------------------------------------
  // Implementation of JavaCallArguments
  
  intptr_t* JavaCallArguments::parameters() {
    // First convert all handles to oops
    for(int i = 0; i < _size; i++) {
      if (_is_oop[i]) {
        // Handle conversion
        _value[i] = cast_from_oop<intptr_t>(Handle::raw_resolve((oop *)_value[i]));
      }
    }
    // Return argument vector
    return _value;
  }
  
  
  class SignatureChekker : public SignatureIterator {
   private:
     bool *_is_oop;
     int   _pos;
     BasicType _return_type;
     intptr_t*   _value;
     Thread* _thread;
  
   public:
    bool _is_return;
  
    SignatureChekker(Symbol* signature, BasicType return_type, bool is_static, bool* is_oop, intptr_t* value, Thread* thread) : SignatureIterator(signature) {
      _is_oop = is_oop;
      _is_return = false;
      _return_type = return_type;
      _pos = 0;
      _value = value;
      _thread = thread;
  
      if (!is_static) {
        check_value(true); // Receiver must be an oop
      }
    }
  
    void check_value(bool type) {
      guarantee(_is_oop[_pos++] == type, "signature does not match pushed arguments");
    }
  
    void check_doing_return(bool state) { _is_return = state; }
  
    void check_return_type(BasicType t) {
      guarantee(_is_return && t == _return_type, "return type does not match");
    }
  
    void check_int(BasicType t) {
      if (_is_return) {
        check_return_type(t);
        return;
      }
      check_value(false);
    }
  
    void check_double(BasicType t) { check_long(t); }
  
    void check_long(BasicType t) {
      if (_is_return) {
        check_return_type(t);
        return;
      }
  
      check_value(false);
      check_value(false);
    }
  
    void check_obj(BasicType t) {
      if (_is_return) {
        check_return_type(t);
        return;
      }
  
      // verify handle and the oop pointed to by handle
      int p = _pos;
      bool bad = false;
      // If argument is oop
      if (_is_oop[p]) {
        intptr_t v = _value[p];
        if (v != 0 ) {
          size_t t = (size_t)v;
          bad = (t < (size_t)os::vm_page_size() ) || !Handle::raw_resolve((oop *)v)->is_oop_or_null(true);
          if (CheckJNICalls && bad) {
            ReportJNIFatalError((JavaThread*)_thread, "Bad JNI oop argument");
          }
        }
        // for the regular debug case.
        assert(!bad, "Bad JNI oop argument");
      }
  
      check_value(true);
    }
  
    void do_bool()                       { check_int(T_BOOLEAN);       }
    void do_char()                       { check_int(T_CHAR);          }
    void do_float()                      { check_int(T_FLOAT);         }
    void do_double()                     { check_double(T_DOUBLE);     }
    void do_byte()                       { check_int(T_BYTE);          }
    void do_short()                      { check_int(T_SHORT);         }
    void do_int()                        { check_int(T_INT);           }
    void do_long()                       { check_long(T_LONG);         }
    void do_void()                       { check_return_type(T_VOID);  }
    void do_object(int begin, int end)   { check_obj(T_OBJECT);        }
    void do_array(int begin, int end)    { check_obj(T_OBJECT);        }
  };
  
  
  void JavaCallArguments::verify(methodHandle method, BasicType return_type,
    Thread *thread) {
    guarantee(method->size_of_parameters() == size_of_parameters(), "wrong no. of arguments pushed");
  
    // Treat T_OBJECT and T_ARRAY as the same
    if (return_type == T_ARRAY) return_type = T_OBJECT;
  
    // Check that oop information is correct
    Symbol* signature = method->signature();
  
    SignatureChekker sc(signature, return_type, method->is_static(),_is_oop, _value, thread);
    sc.iterate_parameters();
    sc.check_doing_return(true);
    sc.iterate_returntype();
  }
  