1 /*
2 * Copyright (c) 2003, 2023, 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/compiledIC.hpp"
28 #include "code/vtableStubs.hpp"
29 #include "interp_masm_x86.hpp"
30 #include "memory/resourceArea.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) {
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 VtableStub* s = new(stub_code_length) VtableStub(true, vtable_index);
52 // Can be null if there is no free space in the code cache.
53 if (s == nullptr) {
54 return nullptr;
55 }
56
57 // Count unused bytes in instruction sequences of variable size.
58 // We add them to the computed buffer size in order to avoid
59 // overflow in subsequently generated stubs.
60 address start_pc;
61 int slop_bytes = 0;
62 int slop_delta = 0;
63 // No variance was detected in vtable stub sizes. Setting index_dependent_slop == 0 will unveil any deviation from this observation.
64 const int index_dependent_slop = 0;
65
66 ResourceMark rm;
67 CodeBuffer cb(s->entry_point(), stub_code_length);
68 MacroAssembler* masm = new MacroAssembler(&cb);
69
70 #if (!defined(PRODUCT) && defined(COMPILER2))
71 if (CountCompiledCalls) {
72 __ incrementq(ExternalAddress(SharedRuntime::nof_megamorphic_calls_addr()), rscratch1);
73 }
74 #endif
75
76 // get receiver (need to skip return address on top of stack)
77 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");
78
79 // Free registers (non-args) are rax, rbx
80
81 // get receiver klass
82 address npe_addr = __ pc();
83 __ load_klass(rax, j_rarg0, rscratch1);
84
85 #ifndef PRODUCT
86 if (DebugVtables) {
87 Label L;
88 start_pc = __ pc();
89 // check offset vs vtable length
90 __ cmpl(Address(rax, Klass::vtable_length_offset()), vtable_index*vtableEntry::size());
91 slop_delta = 12 - (__ pc() - start_pc); // cmpl varies in length, depending on data
92 slop_bytes += slop_delta;
93 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
94
95 __ jcc(Assembler::greater, L);
96 __ movl(rbx, vtable_index);
97 // VTABLE TODO: find upper bound for call_VM length.
98 start_pc = __ pc();
99 __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), j_rarg0, rbx);
100 slop_delta = 550 - (__ pc() - start_pc);
101 slop_bytes += slop_delta;
102 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
103 __ bind(L);
104 }
105 #endif // PRODUCT
106
107 const Register method = rbx;
108
109 // load Method* and target address
110 start_pc = __ pc();
111 __ lookup_virtual_method(rax, vtable_index, method);
112 slop_delta = 8 - (int)(__ pc() - start_pc);
113 slop_bytes += slop_delta;
114 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
115
116 #ifndef PRODUCT
117 if (DebugVtables) {
118 Label L;
119 __ cmpptr(method, NULL_WORD);
120 __ jcc(Assembler::equal, L);
121 __ cmpptr(Address(method, Method::from_compiled_offset()), NULL_WORD);
122 __ jcc(Assembler::notZero, L);
123 __ stop("Vtable entry is null");
124 __ bind(L);
125 }
126 #endif // PRODUCT
127
128 // rax: receiver klass
129 // method (rbx): Method*
130 // rcx: receiver
131 address ame_addr = __ pc();
132 __ jmp( Address(rbx, Method::from_compiled_offset()));
133
134 masm->flush();
135 slop_bytes += index_dependent_slop; // add'l slop for size variance due to large itable offsets
136 bookkeeping(masm, tty, s, npe_addr, ame_addr, true, vtable_index, slop_bytes, index_dependent_slop);
137
138 return s;
139 }
140
141
142 VtableStub* VtableStubs::create_itable_stub(int itable_index) {
143 // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing.
144 const int stub_code_length = code_size_limit(false);
145 VtableStub* s = new(stub_code_length) VtableStub(false, itable_index);
146 // Can be null if there is no free space in the code cache.
147 if (s == nullptr) {
148 return nullptr;
149 }
150
151 // Count unused bytes in instruction sequences of variable size.
152 // We add them to the computed buffer size in order to avoid
153 // overflow in subsequently generated stubs.
154 address start_pc;
155 int slop_bytes = 0;
156 int slop_delta = 0;
157 const int index_dependent_slop = (itable_index == 0) ? 4 : // code size change with transition from 8-bit to 32-bit constant (@index == 16).
158 (itable_index < 16) ? 3 : 0; // index == 0 generates even shorter code.
159
160 ResourceMark rm;
161 CodeBuffer cb(s->entry_point(), stub_code_length);
162 MacroAssembler *masm = new MacroAssembler(&cb);
163
164 #if (!defined(PRODUCT) && defined(COMPILER2))
165 if (CountCompiledCalls) {
166 __ incrementq(ExternalAddress(SharedRuntime::nof_megamorphic_calls_addr()), rscratch1);
167 }
168 #endif // PRODUCT
169
170 // Entry arguments:
171 // rax: CompiledICData
172 // j_rarg0: Receiver
173
174 // Most registers are in use; we'll use rax, rbx, r10, r11
175 // (various calling sequences use r[cd]x, r[sd]i, r[89]; stay away from them)
176 const Register recv_klass_reg = r10;
177 const Register holder_klass_reg = rax; // declaring interface klass (DEFC)
178 const Register resolved_klass_reg = r14; // resolved interface klass (REFC)
179 const Register temp_reg = r11;
180 const Register temp_reg2 = r13;
181 const Register method = rbx;
182 const Register icdata_reg = rax;
183
184 __ movptr(resolved_klass_reg, Address(icdata_reg, CompiledICData::itable_refc_klass_offset()));
185 __ movptr(holder_klass_reg, Address(icdata_reg, CompiledICData::itable_defc_klass_offset()));
186
187 Label L_no_such_interface;
188
189 // get receiver klass (also an implicit null-check)
190 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");
191 address npe_addr = __ pc();
192 __ load_klass(recv_klass_reg, j_rarg0, temp_reg);
193
194 start_pc = __ pc();
195
196 // Receiver subtype check against REFC.
197 // Get selected method from declaring class and itable index
198 __ lookup_interface_method_stub(recv_klass_reg, // input
199 holder_klass_reg, // input
200 resolved_klass_reg, // input
201 method, // output
202 temp_reg,
203 temp_reg2,
204 noreg,
205 itable_index,
206 L_no_such_interface);
207
208 const ptrdiff_t lookupSize = __ pc() - start_pc;
209
210 // We expect we need index_dependent_slop extra bytes. Reason:
211 // The emitted code in lookup_interface_method changes when itable_index exceeds 15.
212 // For linux, a very narrow estimate would be 112, but Solaris requires some more space (130).
213 const ptrdiff_t estimate = 136;
214 const ptrdiff_t codesize = lookupSize + index_dependent_slop;
215 slop_delta = (int)(estimate - codesize);
216 slop_bytes += slop_delta;
217 assert(slop_delta >= 0, "itable #%d: Code size estimate (%d) for lookup_interface_method too small, required: %d", itable_index, (int)estimate, (int)codesize);
218
219 // If we take a trap while this arg is on the stack we will not
220 // be able to walk the stack properly. This is not an issue except
221 // when there are mistakes in this assembly code that could generate
222 // a spurious fault. Ask me how I know...
223
224 // method (rbx): Method*
225 // j_rarg0: receiver
226
227 #ifdef ASSERT
228 if (DebugVtables) {
229 Label L2;
230 __ cmpptr(method, NULL_WORD);
231 __ jcc(Assembler::equal, L2);
232 __ cmpptr(Address(method, Method::from_compiled_offset()), NULL_WORD);
233 __ jcc(Assembler::notZero, L2);
234 __ stop("compiler entrypoint is null");
235 __ bind(L2);
236 }
237 #endif // ASSERT
238
239 address ame_addr = __ pc();
240 __ jmp(Address(method, Method::from_compiled_offset()));
241
242 __ bind(L_no_such_interface);
243 // Handle IncompatibleClassChangeError in itable stubs.
244 // More detailed error message.
245 // We force resolving of the call site by jumping to the "handle
246 // wrong method" stub, and so let the interpreter runtime do all the
247 // dirty work.
248 __ jump(RuntimeAddress(SharedRuntime::get_handle_wrong_method_stub()));
249
250 masm->flush();
251 slop_bytes += index_dependent_slop; // add'l slop for size variance due to large itable offsets
252 bookkeeping(masm, tty, s, npe_addr, ame_addr, false, itable_index, slop_bytes, index_dependent_slop);
253
254 return s;
255 }
256
257 int VtableStub::pd_code_alignment() {
258 // x86 cache line size is 64 bytes, but we want to limit alignment loss.
259 const unsigned int icache_line_size = wordSize;
260 return icache_line_size;
261 }