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