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 *
38
39 // machine-dependent part of VtableStubs: create VtableStub of correct size and
40 // initialize its code
41
42 #define __ masm->
43
44 #ifndef PRODUCT
45 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index);
46 #endif
47
48 // These stubs are used by the compiler only.
49 // Argument registers, which must be preserved:
50 // rcx - receiver (always first argument)
51 // rdx - second argument (if any)
52 // Other registers that might be usable:
53 // rax - inline cache register (is interface for itable stub)
54 // rbx - method (used when calling out to interpreter)
55 // Available now, but may become callee-save at some point:
56 // rsi, rdi
57 // Note that rax and rdx are also used for return values.
58 //
59 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {
60 const int i486_code_length = VtableStub::pd_code_size_limit(true);
61 VtableStub* s = new(i486_code_length) VtableStub(true, vtable_index);
62 // Can be NULL if there is no free space in the code cache.
63 if (s == NULL) {
64 return NULL;
65 }
66
67 ResourceMark rm;
68 CodeBuffer cb(s->entry_point(), i486_code_length);
69 MacroAssembler* masm = new MacroAssembler(&cb);
70
71 #ifndef PRODUCT
72
73 if (CountCompiledCalls) {
74 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
75 }
76 #endif /* PRODUCT */
77
78 // get receiver (need to skip return address on top of stack)
79 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
80
81 // get receiver klass
82 address npe_addr = __ pc();
83 __ movptr(rax, Address(rcx, oopDesc::klass_offset_in_bytes()));
84
85 #ifndef PRODUCT
86 if (DebugVtables) {
87 Label L;
88 // check offset vs vtable length
89 __ cmpl(Address(rax, Klass::vtable_length_offset()), vtable_index*vtableEntry::size());
90 __ jcc(Assembler::greater, L);
91 __ movl(rbx, vtable_index);
92 __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), rcx, rbx);
93 __ bind(L);
94 }
95 #endif // PRODUCT
96
97 const Register method = rbx;
98
99 // load Method* and target address
100 __ lookup_virtual_method(rax, vtable_index, method);
101
102 if (DebugVtables) {
103 Label L;
104 __ cmpptr(method, (int32_t)NULL_WORD);
105 __ jcc(Assembler::equal, L);
106 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
107 __ jcc(Assembler::notZero, L);
108 __ stop("Vtable entry is NULL");
109 __ bind(L);
110 }
111
112 // rax,: receiver klass
113 // method (rbx): Method*
114 // rcx: receiver
115 address ame_addr = __ pc();
116 __ jmp( Address(method, Method::from_compiled_offset()));
117
118 masm->flush();
119
120 if (PrintMiscellaneous && (WizardMode || Verbose)) {
121 tty->print_cr("vtable #%d at " PTR_FORMAT "[%d] left over: %d",
122 vtable_index, p2i(s->entry_point()),
123 (int)(s->code_end() - s->entry_point()),
124 (int)(s->code_end() - __ pc()));
125 }
126 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
127 // shut the door on sizing bugs
128 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
129 assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
130
131 s->set_exception_points(npe_addr, ame_addr);
132 return s;
133 }
134
135
136 VtableStub* VtableStubs::create_itable_stub(int itable_index) {
137 // Note well: pd_code_size_limit is the absolute minimum we can get away with. If you
138 // add code here, bump the code stub size returned by pd_code_size_limit!
139 const int i486_code_length = VtableStub::pd_code_size_limit(false);
140 VtableStub* s = new(i486_code_length) VtableStub(false, itable_index);
141 // Can be NULL if there is no free space in the code cache.
142 if (s == NULL) {
143 return NULL;
144 }
145
146 ResourceMark rm;
147 CodeBuffer cb(s->entry_point(), i486_code_length);
148 MacroAssembler* masm = new MacroAssembler(&cb);
149
150 // Entry arguments:
151 // rax: CompiledICHolder
152 // rcx: Receiver
153
154 #ifndef PRODUCT
155 if (CountCompiledCalls) {
156 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
157 }
158 #endif /* PRODUCT */
159
160 // Most registers are in use; we'll use rax, rbx, rsi, rdi
161 // (If we need to make rsi, rdi callee-save, do a push/pop here.)
162 const Register recv_klass_reg = rsi;
163 const Register holder_klass_reg = rax; // declaring interface klass (DECC)
164 const Register resolved_klass_reg = rbx; // resolved interface klass (REFC)
165 const Register temp_reg = rdi;
166
167 const Register icholder_reg = rax;
168 __ movptr(resolved_klass_reg, Address(icholder_reg, CompiledICHolder::holder_klass_offset()));
169 __ movptr(holder_klass_reg, Address(icholder_reg, CompiledICHolder::holder_metadata_offset()));
170
171 Label L_no_such_interface;
172
173 // get receiver klass (also an implicit null-check)
174 address npe_addr = __ pc();
175 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
176 __ load_klass(recv_klass_reg, rcx);
177
178 // Receiver subtype check against REFC.
179 // Destroys recv_klass_reg value.
180 __ lookup_interface_method(// inputs: rec. class, interface
181 recv_klass_reg, resolved_klass_reg, noreg,
182 // outputs: scan temp. reg1, scan temp. reg2
183 recv_klass_reg, temp_reg,
184 L_no_such_interface,
185 /*return_method=*/false);
186
187 // Get selected method from declaring class and itable index
188 const Register method = rbx;
189 __ load_klass(recv_klass_reg, rcx); // restore recv_klass_reg
190 __ lookup_interface_method(// inputs: rec. class, interface, itable index
191 recv_klass_reg, holder_klass_reg, itable_index,
192 // outputs: method, scan temp. reg
193 method, temp_reg,
194 L_no_such_interface);
195
196 // method (rbx): Method*
197 // rcx: receiver
198
199 #ifdef ASSERT
200 if (DebugVtables) {
201 Label L1;
202 __ cmpptr(method, (int32_t)NULL_WORD);
203 __ jcc(Assembler::equal, L1);
204 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
205 __ jcc(Assembler::notZero, L1);
206 __ stop("Method* is null");
207 __ bind(L1);
208 }
209 #endif // ASSERT
210
211 address ame_addr = __ pc();
212 __ jmp(Address(method, Method::from_compiled_offset()));
213
214 __ bind(L_no_such_interface);
215 // Handle IncompatibleClassChangeError in itable stubs.
216 // More detailed error message.
217 // We force resolving of the call site by jumping to the "handle
218 // wrong method" stub, and so let the interpreter runtime do all the
219 // dirty work.
220 __ jump(RuntimeAddress(SharedRuntime::get_handle_wrong_method_stub()));
221
222 __ flush();
223
224 if (PrintMiscellaneous && (WizardMode || Verbose)) {
225 tty->print_cr("itable #%d at " PTR_FORMAT "[%d] left over: %d",
226 itable_index, p2i(s->entry_point()),
227 (int)(s->code_end() - s->entry_point()),
228 (int)(s->code_end() - __ pc()));
229 }
230 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
231 // shut the door on sizing bugs
232 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
233 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
234
235 s->set_exception_points(npe_addr, ame_addr);
236 return s;
237 }
238
239
240
241 int VtableStub::pd_code_size_limit(bool is_vtable_stub) {
242 if (is_vtable_stub) {
243 // Vtable stub size
244 return (DebugVtables ? 210 : 16) + (CountCompiledCalls ? 6 : 0);
245 } else {
246 // Itable stub size
247 return (DebugVtables ? 256 : 110) + (CountCompiledCalls ? 6 : 0);
248 }
249 // In order to tune these parameters, run the JVM with VM options
250 // +PrintMiscellaneous and +WizardMode to see information about
251 // actual itable stubs. Look for lines like this:
252 // itable #1 at 0x5551212[65] left over: 3
253 // Reduce the constants so that the "left over" number is >=3
254 // for the common cases.
255 // Do not aim at a left-over number of zero, because a
256 // large vtable or itable index (> 16) will require a 32-bit
257 // immediate displacement instead of an 8-bit one.
258 //
259 // The JVM98 app. _202_jess has a megamorphic interface call.
260 // The itable code looks like this:
261 // Decoding VtableStub itbl[1]@1
262 // mov 0x4(%ecx),%esi
263 // mov 0xe8(%esi),%edi
264 // lea 0x130(%esi,%edi,4),%edi
265 // add $0x7,%edi
266 // and $0xfffffff8,%edi
267 // lea 0x4(%esi),%esi
268 // mov (%edi),%ebx
269 // cmp %ebx,%eax
270 // je success
271 // loop:
272 // test %ebx,%ebx
273 // je throw_icce
274 // add $0x8,%edi
275 // mov (%edi),%ebx
276 // cmp %ebx,%eax
277 // jne loop
278 // success:
279 // mov 0x4(%edi),%edi
280 // mov (%esi,%edi,1),%ebx
281 // jmp *0x44(%ebx)
282 // throw_icce:
283 // jmp throw_ICCE_entry
284 }
285
286 int VtableStub::pd_code_alignment() {
287 return wordSize;
288 }
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1 /*
2 * Copyright (c) 1997, 2018, 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 *
38
39 // machine-dependent part of VtableStubs: create VtableStub of correct size and
40 // initialize its code
41
42 #define __ masm->
43
44 #ifndef PRODUCT
45 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index);
46 #endif
47
48 // These stubs are used by the compiler only.
49 // Argument registers, which must be preserved:
50 // rcx - receiver (always first argument)
51 // rdx - second argument (if any)
52 // Other registers that might be usable:
53 // rax - inline cache register (is interface for itable stub)
54 // rbx - method (used when calling out to interpreter)
55 // Available now, but may become callee-save at some point:
56 // rsi, rdi
57 // Note that rax and rdx are also used for return values.
58
59 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {
60 // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing.
61 const int stub_code_length = VtableStub::code_size_limit(true);
62 VtableStub* s = new(stub_code_length) VtableStub(true, vtable_index);
63 // Can be NULL if there is no free space in the code cache.
64 if (s == NULL) {
65 return NULL;
66 }
67
68 // Count unused bytes in instruction sequences of variable size.
69 // We add them to the computed buffer size in order to avoid
70 // overflow in subsequently generated stubs.
71 address start_pc;
72 int slop_bytes = 0;
73 int slop_delta = 0;
74 // No variance was detected in vtable stub sizes. Setting slop32 == 0 will unveil any deviation from this observation.
75 const int slop32 = 0;
76 // const int slop32 = (vtable_index == 0) ? 4 : // code size change with transition from 8-bit to 32-bit constant (@index == 32).
77 // (vtable_index < 32) ? 3 : 0; // index == 0 generates even shorter code.
78
79 ResourceMark rm;
80 CodeBuffer cb(s->entry_point(), stub_code_length);
81 MacroAssembler* masm = new MacroAssembler(&cb);
82
83 #if (!defined(PRODUCT) && defined(COMPILER2))
84 if (CountCompiledCalls) {
85 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
86 }
87 #endif
88
89 // get receiver (need to skip return address on top of stack)
90 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
91
92 // get receiver klass
93 address npe_addr = __ pc();
94 __ movptr(rax, Address(rcx, oopDesc::klass_offset_in_bytes()));
95
96 #ifndef PRODUCT
97 if (DebugVtables) {
98 Label L;
99 start_pc = __ pc();
100 // check offset vs vtable length
101 __ cmpl(Address(rax, Klass::vtable_length_offset()), vtable_index*vtableEntry::size());
102 slop_delta = 6 - (__ pc() - start_pc); // cmpl varies in length, depending on data
103 slop_bytes += slop_delta;
104 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
105
106 __ jcc(Assembler::greater, L);
107 __ movl(rbx, vtable_index);
108 // VTABLE TODO: find upper bound for call_VM length.
109 start_pc = __ pc();
110 __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), rcx, rbx);
111 slop_delta = 470 - (__ pc() - start_pc); // cmpl varies in length, depending on data
112 slop_bytes += slop_delta;
113 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
114 __ bind(L);
115 }
116 #endif // PRODUCT
117
118 const Register method = rbx;
119
120 // load Method* and target address
121 start_pc = __ pc();
122 __ lookup_virtual_method(rax, vtable_index, method);
123 slop_delta = 6 - (int)(__ pc() - start_pc);
124 slop_bytes += slop_delta;
125 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
126
127 #ifndef PRODUCT
128 if (DebugVtables) {
129 Label L;
130 __ cmpptr(method, (int32_t)NULL_WORD);
131 __ jcc(Assembler::equal, L);
132 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
133 __ jcc(Assembler::notZero, L);
134 __ stop("Vtable entry is NULL");
135 __ bind(L);
136 }
137 #endif // PRODUCT
138
139 // rax: receiver klass
140 // method (rbx): Method*
141 // rcx: receiver
142 address ame_addr = __ pc();
143 __ jmp( Address(method, Method::from_compiled_offset()));
144
145 masm->flush();
146 slop_bytes += slop32; // add'l slop for size variance due to large itable offsets
147 bookkeeping(masm, tty, s, npe_addr, ame_addr, true, vtable_index, slop_bytes, slop32);
148
149 return s;
150 }
151
152
153 VtableStub* VtableStubs::create_itable_stub(int itable_index) {
154 // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing.
155 const int stub_code_length = VtableStub::code_size_limit(false);
156 VtableStub* s = new(stub_code_length) VtableStub(false, itable_index);
157 // Can be NULL if there is no free space in the code cache.
158 if (s == NULL) {
159 return NULL;
160 }
161 // Count unused bytes in instruction sequences of variable size.
162 // We add them to the computed buffer size in order to avoid
163 // overflow in subsequently generated stubs.
164 address start_pc;
165 int slop_bytes = 0;
166 int slop_delta = 0;
167 const int slop32 = (itable_index == 0) ? 4 : // code size change with transition from 8-bit to 32-bit constant (@index == 32).
168 (itable_index < 32) ? 3 : 0; // index == 0 generates even shorter code.
169
170 ResourceMark rm;
171 CodeBuffer cb(s->entry_point(), stub_code_length);
172 MacroAssembler* masm = new MacroAssembler(&cb);
173
174 #if (!defined(PRODUCT) && defined(COMPILER2))
175 if (CountCompiledCalls) {
176 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
177 }
178 #endif /* PRODUCT */
179
180 // Entry arguments:
181 // rax: CompiledICHolder
182 // rcx: Receiver
183
184 // Most registers are in use; we'll use rax, rbx, rsi, rdi
185 // (If we need to make rsi, rdi callee-save, do a push/pop here.)
186 const Register recv_klass_reg = rsi;
187 const Register holder_klass_reg = rax; // declaring interface klass (DECC)
188 const Register resolved_klass_reg = rbx; // resolved interface klass (REFC)
189 const Register temp_reg = rdi;
190
191 const Register icholder_reg = rax;
192 __ movptr(resolved_klass_reg, Address(icholder_reg, CompiledICHolder::holder_klass_offset()));
193 __ movptr(holder_klass_reg, Address(icholder_reg, CompiledICHolder::holder_metadata_offset()));
194
195 Label L_no_such_interface;
196
197 // get receiver klass (also an implicit null-check)
198 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
199 address npe_addr = __ pc();
200 __ load_klass(recv_klass_reg, rcx);
201
202 start_pc = __ pc();
203
204 // Receiver subtype check against REFC.
205 // Destroys recv_klass_reg value.
206 __ lookup_interface_method(// inputs: rec. class, interface
207 recv_klass_reg, resolved_klass_reg, noreg,
208 // outputs: scan temp. reg1, scan temp. reg2
209 recv_klass_reg, temp_reg,
210 L_no_such_interface,
211 /*return_method=*/false);
212
213 const ptrdiff_t typecheckSize = __ pc() - start_pc;
214 start_pc = __ pc();
215
216 // Get selected method from declaring class and itable index
217 const Register method = rbx;
218 __ load_klass(recv_klass_reg, rcx); // restore recv_klass_reg
219 __ lookup_interface_method(// inputs: rec. class, interface, itable index
220 recv_klass_reg, holder_klass_reg, itable_index,
221 // outputs: method, scan temp. reg
222 method, temp_reg,
223 L_no_such_interface);
224
225 const ptrdiff_t lookupSize = __ pc() - start_pc;
226
227 // We expect we need slop32 extra bytes. Reason:
228 // The emitted code in lookup_interface_method changes when itable_index exceeds 31.
229 // For windows, a narrow estimate was found to be 104. Other OSes not tested.
230 const ptrdiff_t estimate = 104;
231 const ptrdiff_t codesize = typecheckSize + lookupSize + slop32;
232 slop_delta = (int)(estimate - codesize);
233 slop_bytes += slop_delta;
234 assert(slop_delta >= 0, "itable #%d: Code size estimate (%d) for lookup_interface_method too small, required: %d", itable_index, (int)estimate, (int)codesize);
235
236 // method (rbx): Method*
237 // rcx: receiver
238
239 #ifdef ASSERT
240 if (DebugVtables) {
241 Label L1;
242 __ cmpptr(method, (int32_t)NULL_WORD);
243 __ jcc(Assembler::equal, L1);
244 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
245 __ jcc(Assembler::notZero, L1);
246 __ stop("Method* is null");
247 __ bind(L1);
248 }
249 #endif // ASSERT
250
251 address ame_addr = __ pc();
252 __ jmp(Address(method, Method::from_compiled_offset()));
253
254 __ bind(L_no_such_interface);
255 // Handle IncompatibleClassChangeError in itable stubs.
256 // More detailed error message.
257 // We force resolving of the call site by jumping to the "handle
258 // wrong method" stub, and so let the interpreter runtime do all the
259 // dirty work.
260 __ jump(RuntimeAddress(SharedRuntime::get_handle_wrong_method_stub()));
261
262 masm->flush();
263 slop_bytes += slop32; // add'l slop for size variance due to large itable offsets
264 bookkeeping(masm, tty, s, npe_addr, ame_addr, false, itable_index, slop_bytes, slop32);
265
266 return s;
267 }
268
269 int VtableStub::pd_code_alignment() {
270 // x86 cache line size is 64 bytes, but we want to limit alignment loss.
271 const unsigned int icache_line_size = wordSize;
272 return icache_line_size;
273 }
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