1 /*
2 * Copyright (c) 2003, 2021, 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 #include "precompiled.hpp"
26 #include "asm/macroAssembler.hpp"
27 #include "code/vtableStubs.hpp"
28 #include "interp_masm_x86.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "oops/compiledICHolder.hpp"
31 #include "oops/instanceKlass.hpp"
32 #include "oops/klassVtable.hpp"
33 #include "runtime/sharedRuntime.hpp"
34 #include "vmreg_x86.inline.hpp"
35 #ifdef COMPILER2
36 #include "opto/runtime.hpp"
37 #endif
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 VtableStub* VtableStubs::create_vtable_stub(int vtable_index, bool caller_is_c1) {
49 // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing.
50 const int stub_code_length = code_size_limit(true);
51 Register tmp_load_klass = rscratch1;
52 VtableStub* s = new(stub_code_length) VtableStub(true, vtable_index, caller_is_c1);
53 // Can be NULL if there is no free space in the code cache.
54 if (s == NULL) {
55 return NULL;
56 }
57
58 // Count unused bytes in instruction sequences of variable size.
59 // We add them to the computed buffer size in order to avoid
60 // overflow in subsequently generated stubs.
61 address start_pc;
62 int slop_bytes = 0;
63 int slop_delta = 0;
64 // No variance was detected in vtable stub sizes. Setting index_dependent_slop == 0 will unveil any deviation from this observation.
65 const int index_dependent_slop = 0;
66 ByteSize entry_offset = caller_is_c1 ? Method::from_compiled_inline_offset() : Method::from_compiled_inline_ro_offset();
67
68 ResourceMark rm;
69 CodeBuffer cb(s->entry_point(), stub_code_length);
70 MacroAssembler* masm = new MacroAssembler(&cb);
71
72 #if (!defined(PRODUCT) && defined(COMPILER2))
73 if (CountCompiledCalls) {
74 __ incrementq(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
75 }
76 #endif
77
78 // get receiver (need to skip return address on top of stack)
79 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");
80
81 // Free registers (non-args) are rax, rbx
82
83 // get receiver klass
84 address npe_addr = __ pc();
85 __ load_klass(rax, j_rarg0, tmp_load_klass);
86
87 #ifndef PRODUCT
88 if (DebugVtables) {
89 Label L;
90 start_pc = __ pc();
91 // check offset vs vtable length
92 __ cmpl(Address(rax, Klass::vtable_length_offset()), vtable_index*vtableEntry::size());
93 slop_delta = 12 - (__ pc() - start_pc); // cmpl varies in length, depending on data
94 slop_bytes += slop_delta;
95 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
96
97 __ jcc(Assembler::greater, L);
98 __ movl(rbx, vtable_index);
99 // VTABLE TODO: find upper bound for call_VM length.
100 start_pc = __ pc();
101 __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), j_rarg0, rbx);
102 slop_delta = 550 - (__ pc() - start_pc);
103 slop_bytes += slop_delta;
104 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
105 __ bind(L);
106 }
107 #endif // PRODUCT
108
109 const Register method = rbx;
110
111 // load Method* and target address
112 start_pc = __ pc();
113 __ lookup_virtual_method(rax, vtable_index, method);
114 slop_delta = 8 - (int)(__ pc() - start_pc);
115 slop_bytes += slop_delta;
116 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
117
118 #ifndef PRODUCT
119 if (DebugVtables) {
120 Label L;
121 __ cmpptr(method, (int32_t)NULL_WORD);
122 __ jcc(Assembler::equal, L);
123 __ cmpptr(Address(method, entry_offset), (int32_t)NULL_WORD);
124 __ jcc(Assembler::notZero, L);
125 __ stop("Vtable entry is NULL");
126 __ bind(L);
127 }
128 #endif // PRODUCT
129
130 // rax: receiver klass
131 // method (rbx): Method*
132 // rcx: receiver
133 address ame_addr = __ pc();
134 __ jmp( Address(rbx, entry_offset));
135
136 masm->flush();
137 slop_bytes += index_dependent_slop; // add'l slop for size variance due to large itable offsets
138 bookkeeping(masm, tty, s, npe_addr, ame_addr, true, vtable_index, slop_bytes, index_dependent_slop);
139
140 return s;
141 }
142
143
144 VtableStub* VtableStubs::create_itable_stub(int itable_index, bool caller_is_c1) {
145 // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing.
146 const int stub_code_length = code_size_limit(false);
147 ByteSize entry_offset = caller_is_c1 ? Method::from_compiled_inline_offset() : Method::from_compiled_inline_ro_offset();
148 VtableStub* s = new(stub_code_length) VtableStub(false, itable_index, caller_is_c1);
149 // Can be NULL if there is no free space in the code cache.
150 if (s == NULL) {
151 return NULL;
152 }
153
154 // Count unused bytes in instruction sequences of variable size.
155 // We add them to the computed buffer size in order to avoid
156 // overflow in subsequently generated stubs.
157 address start_pc;
158 int slop_bytes = 0;
159 int slop_delta = 0;
160 const int index_dependent_slop = (itable_index == 0) ? 4 : // code size change with transition from 8-bit to 32-bit constant (@index == 16).
161 (itable_index < 16) ? 3 : 0; // index == 0 generates even shorter code.
162
163 ResourceMark rm;
164 CodeBuffer cb(s->entry_point(), stub_code_length);
165 MacroAssembler *masm = new MacroAssembler(&cb);
166
167 #if (!defined(PRODUCT) && defined(COMPILER2))
168 if (CountCompiledCalls) {
169 __ incrementq(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
170 }
171 #endif // PRODUCT
172
173 // Entry arguments:
174 // rax: CompiledICHolder
175 // j_rarg0: Receiver
176
177 // Most registers are in use; we'll use rax, rbx, r10, r11
178 // (various calling sequences use r[cd]x, r[sd]i, r[89]; stay away from them)
179 const Register recv_klass_reg = r10;
180 const Register holder_klass_reg = rax; // declaring interface klass (DECC)
181 const Register resolved_klass_reg = rbx; // resolved interface klass (REFC)
182 const Register temp_reg = r11;
183
184 const Register icholder_reg = rax;
185 __ movptr(resolved_klass_reg, Address(icholder_reg, CompiledICHolder::holder_klass_offset()));
186 __ movptr(holder_klass_reg, Address(icholder_reg, CompiledICHolder::holder_metadata_offset()));
187
188 Label L_no_such_interface;
189
190 // get receiver klass (also an implicit null-check)
191 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");
192 address npe_addr = __ pc();
193 __ load_klass(recv_klass_reg, j_rarg0, temp_reg);
194
195 start_pc = __ pc();
196
197 // Receiver subtype check against REFC.
198 // Destroys recv_klass_reg value.
199 __ lookup_interface_method(// inputs: rec. class, interface
200 recv_klass_reg, resolved_klass_reg, noreg,
201 // outputs: scan temp. reg1, scan temp. reg2
202 recv_klass_reg, temp_reg,
203 L_no_such_interface,
204 /*return_method=*/false);
205
206 const ptrdiff_t typecheckSize = __ pc() - start_pc;
207 start_pc = __ pc();
208
209 // Get selected method from declaring class and itable index
210 const Register method = rbx;
211 __ load_klass(recv_klass_reg, j_rarg0, temp_reg); // restore recv_klass_reg
212 __ lookup_interface_method(// inputs: rec. class, interface, itable index
213 recv_klass_reg, holder_klass_reg, itable_index,
214 // outputs: method, scan temp. reg
215 method, temp_reg,
216 L_no_such_interface);
217
218 const ptrdiff_t lookupSize = __ pc() - start_pc;
219
220 // We expect we need index_dependent_slop extra bytes. Reason:
221 // The emitted code in lookup_interface_method changes when itable_index exceeds 15.
222 // For linux, a very narrow estimate would be 112, but Solaris requires some more space (130).
223 const ptrdiff_t estimate = 144;
224 const ptrdiff_t codesize = typecheckSize + lookupSize + index_dependent_slop;
225 slop_delta = (int)(estimate - codesize);
226 slop_bytes += slop_delta;
227 assert(slop_delta >= 0, "itable #%d: Code size estimate (%d) for lookup_interface_method too small, required: %d", itable_index, (int)estimate, (int)codesize);
228
229 // If we take a trap while this arg is on the stack we will not
230 // be able to walk the stack properly. This is not an issue except
231 // when there are mistakes in this assembly code that could generate
232 // a spurious fault. Ask me how I know...
233
234 // method (rbx): Method*
235 // j_rarg0: receiver
236
237 #ifdef ASSERT
238 if (DebugVtables) {
239 Label L2;
240 __ cmpptr(method, (int32_t)NULL_WORD);
241 __ jcc(Assembler::equal, L2);
242 __ cmpptr(Address(method, entry_offset), (int32_t)NULL_WORD);
243 __ jcc(Assembler::notZero, L2);
244 __ stop("compiler entrypoint is null");
245 __ bind(L2);
246 }
247 #endif // ASSERT
248
249 address ame_addr = __ pc();
250 __ jmp(Address(method, entry_offset));
251
252 __ bind(L_no_such_interface);
253 // Handle IncompatibleClassChangeError in itable stubs.
254 // More detailed error message.
255 // We force resolving of the call site by jumping to the "handle
256 // wrong method" stub, and so let the interpreter runtime do all the
257 // dirty work.
258 __ jump(RuntimeAddress(SharedRuntime::get_handle_wrong_method_stub()));
259
260 masm->flush();
261 slop_bytes += index_dependent_slop; // add'l slop for size variance due to large itable offsets
262 bookkeeping(masm, tty, s, npe_addr, ame_addr, false, itable_index, slop_bytes, index_dependent_slop);
263
264 return s;
265 }
266
267 int VtableStub::pd_code_alignment() {
268 // x86 cache line size is 64 bytes, but we want to limit alignment loss.
269 const unsigned int icache_line_size = wordSize;
270 return icache_line_size;
271 }