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/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 VtableStub* s = new(stub_code_length) VtableStub(true, vtable_index, caller_is_c1);
52 // Can be nullptr 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 ByteSize entry_offset = caller_is_c1 ? Method::from_compiled_inline_offset() : Method::from_compiled_inline_ro_offset();
66
67 ResourceMark rm;
68 CodeBuffer cb(s->entry_point(), stub_code_length);
69 MacroAssembler* masm = new MacroAssembler(&cb);
70
71 #if (!defined(PRODUCT) && defined(COMPILER2))
72 if (CountCompiledCalls) {
73 __ incrementq(ExternalAddress(SharedRuntime::nof_megamorphic_calls_addr()), rscratch1);
74 }
75 #endif
76
77 // get receiver (need to skip return address on top of stack)
78 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");
79
80 // Free registers (non-args) are rax, rbx
81
82 // get receiver klass
83 address npe_addr = __ pc();
84 __ load_klass(rax, j_rarg0, rscratch1);
85
86 #ifndef PRODUCT
87 if (DebugVtables) {
88 Label L;
89 start_pc = __ pc();
90 // check offset vs vtable length
91 __ cmpl(Address(rax, Klass::vtable_length_offset()), vtable_index*vtableEntry::size());
92 slop_delta = 12 - (__ pc() - start_pc); // cmpl varies in length, depending on data
93 slop_bytes += slop_delta;
94 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
95
96 __ jcc(Assembler::greater, L);
97 __ movl(rbx, vtable_index);
98 // VTABLE TODO: find upper bound for call_VM length.
99 start_pc = __ pc();
100 __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), j_rarg0, rbx);
101 slop_delta = 550 - (__ pc() - start_pc);
102 slop_bytes += slop_delta;
103 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
104 __ bind(L);
105 }
106 #endif // PRODUCT
107
108 const Register method = rbx;
109
110 // load Method* and target address
111 start_pc = __ pc();
112 __ lookup_virtual_method(rax, vtable_index, method);
113 slop_delta = 8 - (int)(__ pc() - start_pc);
114 slop_bytes += slop_delta;
115 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
116
117 #ifndef PRODUCT
118 if (DebugVtables) {
119 Label L;
120 __ cmpptr(method, NULL_WORD);
121 __ jcc(Assembler::equal, L);
122 __ cmpptr(Address(method, entry_offset), NULL_WORD);
123 __ jcc(Assembler::notZero, L);
124 __ stop("Vtable entry is null");
125 __ bind(L);
126 }
127 #endif // PRODUCT
128
129 // rax: receiver klass
130 // method (rbx): Method*
131 // rcx: receiver
132 address ame_addr = __ pc();
133 __ jmp( Address(rbx, entry_offset));
134
135 masm->flush();
136 slop_bytes += index_dependent_slop; // add'l slop for size variance due to large itable offsets
137 bookkeeping(masm, tty, s, npe_addr, ame_addr, true, vtable_index, slop_bytes, index_dependent_slop);
138
139 return s;
140 }
141
142
143 VtableStub* VtableStubs::create_itable_stub(int itable_index, bool caller_is_c1) {
144 // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing.
145 const int stub_code_length = code_size_limit(false);
146 ByteSize entry_offset = caller_is_c1 ? Method::from_compiled_inline_offset() : Method::from_compiled_inline_ro_offset();
147 VtableStub* s = new(stub_code_length) VtableStub(false, itable_index, caller_is_c1);
148 // Can be nullptr if there is no free space in the code cache.
149 if (s == nullptr) {
150 return nullptr;
151 }
152
153 // Count unused bytes in instruction sequences of variable size.
154 // We add them to the computed buffer size in order to avoid
155 // overflow in subsequently generated stubs.
156 address start_pc;
157 int slop_bytes = 0;
158 int slop_delta = 0;
159 const int index_dependent_slop = (itable_index == 0) ? 4 : // code size change with transition from 8-bit to 32-bit constant (@index == 16).
160 (itable_index < 16) ? 3 : 0; // index == 0 generates even shorter code.
161
162 ResourceMark rm;
163 CodeBuffer cb(s->entry_point(), stub_code_length);
164 MacroAssembler *masm = new MacroAssembler(&cb);
165
166 #if (!defined(PRODUCT) && defined(COMPILER2))
167 if (CountCompiledCalls) {
168 __ incrementq(ExternalAddress(SharedRuntime::nof_megamorphic_calls_addr()), rscratch1);
169 }
170 #endif // PRODUCT
171
172 // Entry arguments:
173 // rax: CompiledICHolder
174 // j_rarg0: Receiver
175
176 // Most registers are in use; we'll use rax, rbx, r10, r11
177 // (various calling sequences use r[cd]x, r[sd]i, r[89]; stay away from them)
178 const Register recv_klass_reg = r10;
179 const Register holder_klass_reg = rax; // declaring interface klass (DECC)
180 const Register resolved_klass_reg = r14; // resolved interface klass (REFC)
181 const Register temp_reg = r11;
182 const Register temp_reg2 = r13;
183 const Register method = rbx;
184 const Register icholder_reg = rax;
185
186 __ movptr(resolved_klass_reg, Address(icholder_reg, CompiledICHolder::holder_klass_offset()));
187 __ movptr(holder_klass_reg, Address(icholder_reg, CompiledICHolder::holder_metadata_offset()));
188
189 Label L_no_such_interface;
190
191 // get receiver klass (also an implicit null-check)
192 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");
193 address npe_addr = __ pc();
194 __ load_klass(recv_klass_reg, j_rarg0, temp_reg);
195
196 start_pc = __ pc();
197
198 // Receiver subtype check against REFC.
199 // Get selected method from declaring class and itable index
200 __ lookup_interface_method_stub(recv_klass_reg, // input
201 holder_klass_reg, // input
202 resolved_klass_reg, // input
203 method, // output
204 temp_reg,
205 temp_reg2,
206 noreg,
207 itable_index,
208 L_no_such_interface);
209
210 const ptrdiff_t lookupSize = __ pc() - start_pc;
211
212 // We expect we need index_dependent_slop extra bytes. Reason:
213 // The emitted code in lookup_interface_method changes when itable_index exceeds 15.
214 // For linux, a very narrow estimate would be 112, but Solaris requires some more space (130).
215 const ptrdiff_t estimate = 144;
216 const ptrdiff_t codesize = lookupSize + index_dependent_slop;
217 slop_delta = (int)(estimate - codesize);
218 slop_bytes += slop_delta;
219 assert(slop_delta >= 0, "itable #%d: Code size estimate (%d) for lookup_interface_method too small, required: %d", itable_index, (int)estimate, (int)codesize);
220
221 // If we take a trap while this arg is on the stack we will not
222 // be able to walk the stack properly. This is not an issue except
223 // when there are mistakes in this assembly code that could generate
224 // a spurious fault. Ask me how I know...
225
226 // method (rbx): Method*
227 // j_rarg0: receiver
228
229 #ifdef ASSERT
230 if (DebugVtables) {
231 Label L2;
232 __ cmpptr(method, NULL_WORD);
233 __ jcc(Assembler::equal, L2);
234 __ cmpptr(Address(method, entry_offset), NULL_WORD);
235 __ jcc(Assembler::notZero, L2);
236 __ stop("compiler entrypoint is null");
237 __ bind(L2);
238 }
239 #endif // ASSERT
240
241 address ame_addr = __ pc();
242 __ jmp(Address(method, entry_offset));
243
244 __ bind(L_no_such_interface);
245 // Handle IncompatibleClassChangeError in itable stubs.
246 // More detailed error message.
247 // We force resolving of the call site by jumping to the "handle
248 // wrong method" stub, and so let the interpreter runtime do all the
249 // dirty work.
250 __ jump(RuntimeAddress(SharedRuntime::get_handle_wrong_method_stub()));
251
252 masm->flush();
253 slop_bytes += index_dependent_slop; // add'l slop for size variance due to large itable offsets
254 bookkeeping(masm, tty, s, npe_addr, ame_addr, false, itable_index, slop_bytes, index_dependent_slop);
255
256 return s;
257 }
258
259 int VtableStub::pd_code_alignment() {
260 // x86 cache line size is 64 bytes, but we want to limit alignment loss.
261 const unsigned int icache_line_size = wordSize;
262 return icache_line_size;
263 }