1 /*
   2  * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_RUNTIME_JAVACALLS_HPP
  26 #define SHARE_VM_RUNTIME_JAVACALLS_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "oops/method.hpp"
  30 #include "runtime/handles.hpp"
  31 #include "runtime/javaFrameAnchor.hpp"
  32 #include "runtime/thread.hpp"
  33 #include "runtime/vmThread.hpp"
  34 #include "utilities/macros.hpp"
  35 
  36 #include CPU_HEADER(jniTypes)
  37 
  38 // A JavaCallWrapper is constructed before each JavaCall and destructed after the call.
  39 // Its purpose is to allocate/deallocate a new handle block and to save/restore the last
  40 // Java fp/sp. A pointer to the JavaCallWrapper is stored on the stack.
  41 
  42 class JavaCallWrapper: StackObj {
  43   friend class VMStructs;
  44  private:
  45   JavaThread*      _thread;                 // the thread to which this call belongs
  46   JNIHandleBlock*  _handles;                // the saved handle block
  47   Method*          _callee_method;          // to be able to collect arguments if entry frame is top frame
  48   oop              _receiver;               // the receiver of the call (if a non-static call)
  49 
  50   JavaFrameAnchor  _anchor;                 // last thread anchor state that we must restore
  51 
  52   JavaValue*       _result;                 // result value
  53 
  54  public:
  55   // Construction/destruction
  56    JavaCallWrapper(methodHandle callee_method, Handle receiver, JavaValue* result, TRAPS);
  57   ~JavaCallWrapper();
  58 
  59   // Accessors
  60   JavaThread*      thread() const           { return _thread; }
  61   JNIHandleBlock*  handles() const          { return _handles; }
  62 
  63   JavaFrameAnchor* anchor(void)             { return &_anchor; }
  64 
  65   JavaValue*       result() const           { return _result; }
  66   // GC support
  67   Method*          callee_method()          { return _callee_method; }
  68   oop              receiver()               { return _receiver; }
  69   void             oops_do(OopClosure* f);
  70 
  71   bool             is_first_frame() const   { return _anchor.last_Java_sp() == NULL; }
  72 
  73 };
  74 
  75 
  76 // Encapsulates arguments to a JavaCall (faster, safer, and more convenient than using var-args)
  77 class JavaCallArguments : public StackObj {
  78  private:
  79   enum Constants {
  80    _default_size = 8    // Must be at least # of arguments in JavaCalls methods
  81   };
  82 
  83   intptr_t    _value_buffer [_default_size + 1];
  84   bool        _is_oop_buffer[_default_size + 1];
  85 
  86   intptr_t*   _value;
  87   bool*       _is_oop;
  88   int         _size;
  89   int         _max_size;
  90   bool        _start_at_zero;      // Support late setting of receiver
  91   JVMCI_ONLY(nmethod*    _alternative_target;) // Nmethod that should be called instead of normal target
  92 
  93   void initialize() {
  94     // Starts at first element to support set_receiver.
  95     _value    = &_value_buffer[1];
  96     _is_oop   = &_is_oop_buffer[1];
  97 
  98     _max_size = _default_size;
  99     _size = 0;
 100     _start_at_zero = false;
 101     JVMCI_ONLY(_alternative_target = NULL;)
 102   }
 103 
 104  public:
 105   JavaCallArguments() { initialize(); }
 106 
 107   JavaCallArguments(Handle receiver) {
 108     initialize();
 109     push_oop(receiver);
 110   }
 111 
 112   JavaCallArguments(int max_size) {
 113     if (max_size > _default_size) {
 114       _value  = NEW_RESOURCE_ARRAY(intptr_t, max_size + 1);
 115       _is_oop = NEW_RESOURCE_ARRAY(bool, max_size + 1);
 116 
 117       // Reserve room for potential receiver in value and is_oop
 118       _value++; _is_oop++;
 119 
 120       _max_size = max_size;
 121       _size = 0;
 122       _start_at_zero = false;
 123       JVMCI_ONLY(_alternative_target = NULL;)
 124     } else {
 125       initialize();
 126     }
 127   }
 128 
 129 #if INCLUDE_JVMCI
 130   void set_alternative_target(nmethod* target) {
 131     _alternative_target = target;
 132   }
 133 
 134   nmethod* alternative_target() {
 135     return _alternative_target;
 136   }
 137 #endif
 138 
 139   inline void push_oop(Handle h)    { _is_oop[_size] = true;
 140                                JNITypes::put_obj((oop)h.raw_value(), _value, _size); }
 141 
 142   inline void push_int(int i)       { _is_oop[_size] = false;
 143                                JNITypes::put_int(i, _value, _size); }
 144 
 145   inline void push_double(double d) { _is_oop[_size] = false; _is_oop[_size + 1] = false;
 146                                JNITypes::put_double(d, _value, _size); }
 147 
 148   inline void push_long(jlong l)    { _is_oop[_size] = false; _is_oop[_size + 1] = false;
 149                                JNITypes::put_long(l, _value, _size); }
 150 
 151   inline void push_float(float f)   { _is_oop[_size] = false;
 152                                JNITypes::put_float(f, _value, _size); }
 153 
 154   // receiver
 155   Handle receiver() {
 156     assert(_size > 0, "must at least be one argument");
 157     assert(_is_oop[0], "first argument must be an oop");
 158     assert(_value[0] != 0, "receiver must be not-null");
 159     return Handle((oop*)_value[0], false);
 160   }
 161 
 162   void set_receiver(Handle h) {
 163     assert(_start_at_zero == false, "can only be called once");
 164     _start_at_zero = true;
 165     _is_oop--;
 166     _value--;
 167     _size++;
 168     _is_oop[0] = true;
 169     _value[0] = (intptr_t)h.raw_value();
 170   }
 171 
 172   // Converts all Handles to oops, and returns a reference to parameter vector
 173   intptr_t* parameters() ;
 174   int   size_of_parameters() const { return _size; }
 175 
 176   // Verify that pushed arguments fits a given method
 177   void verify(const methodHandle& method, BasicType return_type, Thread *thread);
 178 };
 179 
 180 // All calls to Java have to go via JavaCalls. Sets up the stack frame
 181 // and makes sure that the last_Java_frame pointers are chained correctly.
 182 //
 183 
 184 class JavaCalls: AllStatic {
 185   static void call_helper(JavaValue* result, const methodHandle& method, JavaCallArguments* args, TRAPS);
 186  public:
 187   // call_special
 188   // ------------
 189   // The receiver must be first oop in argument list
 190   static void call_special(JavaValue* result, KlassHandle klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS);
 191 
 192   static void call_special(JavaValue* result, Handle receiver, KlassHandle klass, Symbol* name, Symbol* signature, TRAPS); // No args
 193   static void call_special(JavaValue* result, Handle receiver, KlassHandle klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS);
 194   static void call_special(JavaValue* result, Handle receiver, KlassHandle klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS);
 195 
 196   // virtual call
 197   // ------------
 198 
 199   // The receiver must be first oop in argument list
 200   static void call_virtual(JavaValue* result, KlassHandle spec_klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS);
 201 
 202   static void call_virtual(JavaValue* result, Handle receiver, KlassHandle spec_klass, Symbol* name, Symbol* signature, TRAPS); // No args
 203   static void call_virtual(JavaValue* result, Handle receiver, KlassHandle spec_klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS);
 204   static void call_virtual(JavaValue* result, Handle receiver, KlassHandle spec_klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS);
 205 
 206   // Static call
 207   // -----------
 208   static void call_static(JavaValue* result, KlassHandle klass, Symbol* name, Symbol* signature, JavaCallArguments* args, TRAPS);
 209 
 210   static void call_static(JavaValue* result, KlassHandle klass, Symbol* name, Symbol* signature, TRAPS);
 211   static void call_static(JavaValue* result, KlassHandle klass, Symbol* name, Symbol* signature, Handle arg1, TRAPS);
 212   static void call_static(JavaValue* result, KlassHandle klass, Symbol* name, Symbol* signature, Handle arg1, Handle arg2, TRAPS);
 213 
 214   // Low-level interface
 215   static void call(JavaValue* result, const methodHandle& method, JavaCallArguments* args, TRAPS);
 216 };
 217 
 218 #endif // SHARE_VM_RUNTIME_JAVACALLS_HPP