1 /*
   2  * Copyright (c) 2010, 2011, 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 // Platform-specific definitions for method handles.
  26 // These definitions are inlined into class MethodHandles.
  27 
  28 // Adapters
  29 enum /* platform_dependent_constants */ {
  30   adapter_code_size = NOT_LP64(30000 DEBUG_ONLY(+ 10000)) LP64_ONLY(80000 DEBUG_ONLY(+ 120000))
  31 };
  32 
  33 public:
  34 
  35 // The stack just after the recursive call from a ricochet frame
  36 // looks something like this.  Offsets are marked in words, not bytes.
  37 // rsi (r13 on LP64) is part of the interpreter calling sequence
  38 // which tells the callee where is my real rsp (for frame walking).
  39 // (...lower memory addresses)
  40 // rsp:     [ return pc                 ]   always the global RicochetBlob::bounce_addr
  41 // rsp+1:   [ recursive arg N           ]
  42 // rsp+2:   [ recursive arg N-1         ]
  43 // ...
  44 // rsp+N:   [ recursive arg 1           ]
  45 // rsp+N+1: [ recursive method handle   ]
  46 // ...
  47 // rbp-6:   [ cleanup continuation pc   ]   <-- (struct RicochetFrame)
  48 // rbp-5:   [ saved target MH           ]   the MH we will call on the saved args
  49 // rbp-4:   [ saved args layout oop     ]   an int[] array which describes argument layout
  50 // rbp-3:   [ saved args pointer        ]   address of transformed adapter arg M (slot 0)
  51 // rbp-2:   [ conversion                ]   information about how the return value is used
  52 // rbp-1:   [ exact sender sp           ]   exact TOS (rsi/r13) of original sender frame
  53 // rbp+0:   [ saved sender fp           ]   (for original sender of AMH)
  54 // rbp+1:   [ saved sender pc           ]   (back to original sender of AMH)
  55 // rbp+2:   [ transformed adapter arg M ]   <-- (extended TOS of original sender)
  56 // rbp+3:   [ transformed adapter arg M-1]
  57 // ...
  58 // rbp+M+1: [ transformed adapter arg 1 ]
  59 // rbp+M+2: [ padding                   ] <-- (rbp + saved args base offset)
  60 // ...      [ optional padding]
  61 // (higher memory addresses...)
  62 //
  63 // The arguments originally passed by the original sender
  64 // are lost, and arbitrary amounts of stack motion might have
  65 // happened due to argument transformation.
  66 // (This is done by C2I/I2C adapters and non-direct method handles.)
  67 // This is why there is an unpredictable amount of memory between
  68 // the extended and exact TOS of the sender.
  69 // The ricochet adapter itself will also (in general) perform
  70 // transformations before the recursive call.
  71 //
  72 // The transformed and saved arguments, immediately above the saved
  73 // return PC, are a well-formed method handle invocation ready to execute.
  74 // When the GC needs to walk the stack, these arguments are described
  75 // via the saved arg types oop, an int[] array with a private format.
  76 // This array is derived from the type of the transformed adapter
  77 // method handle, which also sits at the base of the saved argument
  78 // bundle.  Since the GC may not be able to fish out the int[]
  79 // array, so it is pushed explicitly on the stack.  This may be
  80 // an unnecessary expense.
  81 //
  82 // The following register conventions are significant at this point:
  83 // rsp       the thread stack, as always; preserved by caller
  84 // rsi/r13   exact TOS of recursive frame (contents of [rbp-2])
  85 // rcx       recursive method handle (contents of [rsp+N+1])
  86 // rbp       preserved by caller (not used by caller)
  87 // Unless otherwise specified, all registers can be blown by the call.
  88 //
  89 // If this frame must be walked, the transformed adapter arguments
  90 // will be found with the help of the saved arguments descriptor.
  91 //
  92 // Therefore, the descriptor must match the referenced arguments.
  93 // The arguments must be followed by at least one word of padding,
  94 // which will be necessary to complete the final method handle call.
  95 // That word is not treated as holding an oop.  Neither is the word
  96 //
  97 // The word pointed to by the return argument pointer is not
  98 // treated as an oop, even if points to a saved argument.
  99 // This allows the saved argument list to have a "hole" in it
 100 // to receive an oop from the recursive call.
 101 // (The hole might temporarily contain RETURN_VALUE_PLACEHOLDER.)
 102 //
 103 // When the recursive callee returns, RicochetBlob::bounce_addr will
 104 // immediately jump to the continuation stored in the RF.
 105 // This continuation will merge the recursive return value
 106 // into the saved argument list.  At that point, the original
 107 // rsi, rbp, and rsp will be reloaded, the ricochet frame will
 108 // disappear, and the final target of the adapter method handle
 109 // will be invoked on the transformed argument list.
 110 
 111 class RicochetFrame {
 112   friend class MethodHandles;
 113 
 114  private:
 115   intptr_t* _continuation;          // what to do when control gets back here
 116   oopDesc*  _saved_target;          // target method handle to invoke on saved_args
 117   oopDesc*  _saved_args_layout;     // caching point for MethodTypeForm.vmlayout cookie
 118   intptr_t* _saved_args_base;       // base of pushed arguments (slot 0, arg N) (-3)
 119   intptr_t  _conversion;            // misc. information from original AdapterMethodHandle (-2)
 120   intptr_t* _exact_sender_sp;       // parallel to interpreter_frame_sender_sp (-1)
 121   intptr_t* _sender_link;           // *must* coincide with frame::link_offset (0)
 122   address   _sender_pc;             // *must* coincide with frame::return_addr_offset (1)
 123 
 124  public:
 125   intptr_t* continuation() const        { return _continuation; }
 126   oop       saved_target() const        { return _saved_target; }
 127   oop       saved_args_layout() const   { return _saved_args_layout; }
 128   intptr_t* saved_args_base() const     { return _saved_args_base; }
 129   intptr_t  conversion() const          { return _conversion; }
 130   intptr_t* exact_sender_sp() const     { return _exact_sender_sp; }
 131   intptr_t* sender_link() const         { return _sender_link; }
 132   address   sender_pc() const           { return _sender_pc; }
 133 
 134   intptr_t* extended_sender_sp() const  { return saved_args_base(); }
 135 
 136   intptr_t  return_value_slot_number() const {
 137     return adapter_conversion_vminfo(conversion());
 138   }
 139   BasicType return_value_type() const {
 140     return adapter_conversion_dest_type(conversion());
 141   }
 142   bool has_return_value_slot() const {
 143     return return_value_type() != T_VOID;
 144   }
 145   intptr_t* return_value_slot_addr() const {
 146     assert(has_return_value_slot(), "");
 147     return saved_arg_slot_addr(return_value_slot_number());
 148   }
 149   intptr_t* saved_target_slot_addr() const {
 150     return saved_arg_slot_addr(saved_args_length());
 151   }
 152   intptr_t* saved_arg_slot_addr(int slot) const {
 153     assert(slot >= 0, "");
 154     return (intptr_t*)( (address)saved_args_base() + (slot * Interpreter::stackElementSize) );
 155   }
 156 
 157   jint      saved_args_length() const;
 158   jint      saved_arg_offset(int arg) const;
 159 
 160   // GC interface
 161   oop*  saved_target_addr()                     { return (oop*)&_saved_target; }
 162   oop*  saved_args_layout_addr()                { return (oop*)&_saved_args_layout; }
 163 
 164   oop  compute_saved_args_layout(bool read_cache, bool write_cache);
 165 
 166   // Compiler/assembler interface.
 167   static int continuation_offset_in_bytes()     { return offset_of(RicochetFrame, _continuation); }
 168   static int saved_target_offset_in_bytes()     { return offset_of(RicochetFrame, _saved_target); }
 169   static int saved_args_layout_offset_in_bytes(){ return offset_of(RicochetFrame, _saved_args_layout); }
 170   static int saved_args_base_offset_in_bytes()  { return offset_of(RicochetFrame, _saved_args_base); }
 171   static int conversion_offset_in_bytes()       { return offset_of(RicochetFrame, _conversion); }
 172   static int exact_sender_sp_offset_in_bytes()  { return offset_of(RicochetFrame, _exact_sender_sp); }
 173   static int sender_link_offset_in_bytes()      { return offset_of(RicochetFrame, _sender_link); }
 174   static int sender_pc_offset_in_bytes()        { return offset_of(RicochetFrame, _sender_pc); }
 175 
 176   // This value is not used for much, but it apparently must be nonzero.
 177   static int frame_size_in_bytes()              { return sender_link_offset_in_bytes(); }
 178 
 179 #ifdef ASSERT
 180   // The magic number is supposed to help find ricochet frames within the bytes of stack dumps.
 181   enum { MAGIC_NUMBER_1 = 0xFEED03E, MAGIC_NUMBER_2 = 0xBEEF03E };
 182   static int magic_number_1_offset_in_bytes()   { return -wordSize; }
 183   static int magic_number_2_offset_in_bytes()   { return sizeof(RicochetFrame); }
 184   intptr_t magic_number_1() const               { return *(intptr_t*)((address)this + magic_number_1_offset_in_bytes()); };
 185   intptr_t magic_number_2() const               { return *(intptr_t*)((address)this + magic_number_2_offset_in_bytes()); };
 186 #endif //ASSERT
 187 
 188   enum { RETURN_VALUE_PLACEHOLDER = (NOT_DEBUG(0) DEBUG_ONLY(42)) };
 189 
 190   static void verify_offsets() NOT_DEBUG_RETURN;
 191   void verify() const NOT_DEBUG_RETURN; // check for MAGIC_NUMBER, etc.
 192   void zap_arguments() NOT_DEBUG_RETURN;
 193 
 194   static void generate_ricochet_blob(MacroAssembler* _masm,
 195                                      // output params:
 196                                      int* bounce_offset,
 197                                      int* exception_offset,
 198                                      int* frame_size_in_words);
 199 
 200   static void enter_ricochet_frame(MacroAssembler* _masm,
 201                                    Register rcx_recv,
 202                                    Register rax_argv,
 203                                    address return_handler,
 204                                    Register rbx_temp);
 205   static void leave_ricochet_frame(MacroAssembler* _masm,
 206                                    Register rcx_recv,
 207                                    Register new_sp_reg,
 208                                    Register sender_pc_reg);
 209 
 210   static Address frame_address(int offset = 0) {
 211     // The RicochetFrame is found by subtracting a constant offset from rbp.
 212     return Address(rbp, - sender_link_offset_in_bytes() + offset);
 213   }
 214 
 215   static RicochetFrame* from_frame(const frame& fr) {
 216     address bp = (address) fr.fp();
 217     RicochetFrame* rf = (RicochetFrame*)(bp - sender_link_offset_in_bytes());
 218     rf->verify();
 219     return rf;
 220   }
 221 
 222   static void verify_clean(MacroAssembler* _masm) NOT_DEBUG_RETURN;
 223 };
 224 
 225 // Additional helper methods for MethodHandles code generation:
 226 public:
 227   static void load_klass_from_Class(MacroAssembler* _masm, Register klass_reg);
 228   static void load_conversion_vminfo(MacroAssembler* _masm, Register reg, Address conversion_field_addr);
 229   static void load_conversion_dest_type(MacroAssembler* _masm, Register reg, Address conversion_field_addr);
 230 
 231   static void load_stack_move(MacroAssembler* _masm,
 232                               Register rdi_stack_move,
 233                               Register rcx_amh,
 234                               bool might_be_negative);
 235 
 236   static void insert_arg_slots(MacroAssembler* _masm,
 237                                RegisterOrConstant arg_slots,
 238                                Register rax_argslot,
 239                                Register rbx_temp, Register rdx_temp);
 240 
 241   static void remove_arg_slots(MacroAssembler* _masm,
 242                                RegisterOrConstant arg_slots,
 243                                Register rax_argslot,
 244                                Register rbx_temp, Register rdx_temp);
 245 
 246   static void push_arg_slots(MacroAssembler* _masm,
 247                                    Register rax_argslot,
 248                                    RegisterOrConstant slot_count,
 249                                    int skip_words_count,
 250                                    Register rbx_temp, Register rdx_temp);
 251 
 252   static void move_arg_slots_up(MacroAssembler* _masm,
 253                                 Register rbx_bottom,  // invariant
 254                                 Address  top_addr,    // can use rax_temp
 255                                 RegisterOrConstant positive_distance_in_slots,
 256                                 Register rax_temp, Register rdx_temp);
 257 
 258   static void move_arg_slots_down(MacroAssembler* _masm,
 259                                   Address  bottom_addr,  // can use rax_temp
 260                                   Register rbx_top,      // invariant
 261                                   RegisterOrConstant negative_distance_in_slots,
 262                                   Register rax_temp, Register rdx_temp);
 263 
 264   static void move_typed_arg(MacroAssembler* _masm,
 265                              BasicType type, bool is_element,
 266                              Address slot_dest, Address value_src,
 267                              Register rbx_temp, Register rdx_temp);
 268 
 269   static void move_return_value(MacroAssembler* _masm, BasicType type,
 270                                 Address return_slot);
 271 
 272   static void verify_argslot(MacroAssembler* _masm, Register argslot_reg,
 273                              const char* error_message) NOT_DEBUG_RETURN;
 274 
 275   static void verify_argslots(MacroAssembler* _masm,
 276                               RegisterOrConstant argslot_count,
 277                               Register argslot_reg,
 278                               bool negate_argslot,
 279                               const char* error_message) NOT_DEBUG_RETURN;
 280 
 281   static void verify_stack_move(MacroAssembler* _masm,
 282                                 RegisterOrConstant arg_slots,
 283                                 int direction) NOT_DEBUG_RETURN;
 284 
 285   static void verify_klass(MacroAssembler* _masm,
 286                            Register obj, KlassHandle klass,
 287                            const char* error_message = "wrong klass") NOT_DEBUG_RETURN;
 288 
 289   static void verify_method_handle(MacroAssembler* _masm, Register mh_reg) {
 290     verify_klass(_masm, mh_reg, SystemDictionaryHandles::MethodHandle_klass(),
 291                  "reference is a MH");
 292   }
 293 
 294   // Similar to InterpreterMacroAssembler::jump_from_interpreted.
 295   // Takes care of special dispatch from single stepping too.
 296   static void jump_from_method_handle(MacroAssembler* _masm, Register method, Register temp);
 297 
 298   static void trace_method_handle(MacroAssembler* _masm, const char* adaptername) PRODUCT_RETURN;
 299 
 300   static Register saved_last_sp_register() {
 301     // Should be in sharedRuntime, not here.
 302     return LP64_ONLY(r13) NOT_LP64(rsi);
 303   }