1 /*
2 * Copyright (c) 1997, 2014, 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/instanceKlass.hpp"
31 #include "oops/klassVtable.hpp"
32 #include "runtime/sharedRuntime.hpp"
33 #include "vmreg_x86.inline.hpp"
34 #ifdef COMPILER2
35 #include "opto/runtime.hpp"
36 #endif
37
38 // machine-dependent part of VtableStubs: create VtableStub of correct size and
39 // initialize its code
40
41 #define __ masm->
42
43 #ifndef PRODUCT
44 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index);
45 #endif
46
47 // These stubs are used by the compiler only.
48 // Argument registers, which must be preserved:
49 // rcx - receiver (always first argument)
50 // rdx - second argument (if any)
51 // Other registers that might be usable:
52 // rax - inline cache register (is interface for itable stub)
53 // rbx - method (used when calling out to interpreter)
54 // Available now, but may become callee-save at some point:
55 // rsi, rdi
56 // Note that rax and rdx are also used for return values.
57 //
58 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {
59 const int i486_code_length = VtableStub::pd_code_size_limit(true);
60 VtableStub* s = new(i486_code_length) VtableStub(true, vtable_index);
61 // Can be NULL if there is no free space in the code cache.
62 if (s == NULL) {
63 return NULL;
64 }
65
66 ResourceMark rm;
67 CodeBuffer cb(s->entry_point(), i486_code_length);
68 MacroAssembler* masm = new MacroAssembler(&cb);
69
70 #ifndef PRODUCT
71
72 if (CountCompiledCalls) {
73 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
74 }
75 #endif /* PRODUCT */
76
77 // get receiver (need to skip return address on top of stack)
78 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
79
80 // get receiver klass
81 address npe_addr = __ pc();
82 __ movptr(rax, Address(rcx, oopDesc::klass_offset_in_bytes()));
83
84 #ifndef PRODUCT
85 if (DebugVtables) {
86 Label L;
87 // check offset vs vtable length
88 __ cmpl(Address(rax, InstanceKlass::vtable_length_offset()*wordSize), vtable_index*vtableEntry::size());
89 __ jcc(Assembler::greater, L);
90 __ movl(rbx, vtable_index);
91 __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), rcx, rbx);
92 __ bind(L);
93 }
94 #endif // PRODUCT
95
96 const Register method = rbx;
97
98 // load Method* and target address
99 __ lookup_virtual_method(rax, vtable_index, method);
100
101 if (DebugVtables) {
102 Label L;
103 __ cmpptr(method, (int32_t)NULL_WORD);
104 __ jcc(Assembler::equal, L);
105 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
106 __ jcc(Assembler::notZero, L);
107 __ stop("Vtable entry is NULL");
108 __ bind(L);
109 }
110
111 // rax,: receiver klass
112 // method (rbx): Method*
113 // rcx: receiver
114 address ame_addr = __ pc();
115 __ jmp( Address(method, Method::from_compiled_offset()));
116
117 masm->flush();
118
119 if (PrintMiscellaneous && (WizardMode || Verbose)) {
120 tty->print_cr("vtable #%d at " PTR_FORMAT "[%d] left over: %d",
121 vtable_index, p2i(s->entry_point()),
122 (int)(s->code_end() - s->entry_point()),
123 (int)(s->code_end() - __ pc()));
124 }
125 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
126 // shut the door on sizing bugs
127 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
128 assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
129
130 s->set_exception_points(npe_addr, ame_addr);
131 return s;
132 }
133
134
135 VtableStub* VtableStubs::create_itable_stub(int itable_index) {
136 // Note well: pd_code_size_limit is the absolute minimum we can get away with. If you
137 // add code here, bump the code stub size returned by pd_code_size_limit!
138 const int i486_code_length = VtableStub::pd_code_size_limit(false);
139 VtableStub* s = new(i486_code_length) VtableStub(false, itable_index);
140 // Can be NULL if there is no free space in the code cache.
141 if (s == NULL) {
142 return NULL;
143 }
144
145 ResourceMark rm;
146 CodeBuffer cb(s->entry_point(), i486_code_length);
147 MacroAssembler* masm = new MacroAssembler(&cb);
148
149 // Entry arguments:
150 // rax,: Interface
151 // rcx: Receiver
152
153 #ifndef PRODUCT
154 if (CountCompiledCalls) {
155 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
156 }
157 #endif /* PRODUCT */
158 // get receiver (need to skip return address on top of stack)
159
160 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
161
162 // get receiver klass (also an implicit null-check)
163 address npe_addr = __ pc();
164 __ movptr(rsi, Address(rcx, oopDesc::klass_offset_in_bytes()));
165
166 // Most registers are in use; we'll use rax, rbx, rsi, rdi
167 // (If we need to make rsi, rdi callee-save, do a push/pop here.)
168 const Register method = rbx;
169 Label throw_icce;
170
171 // Get Method* and entrypoint for compiler
172 __ lookup_interface_method(// inputs: rec. class, interface, itable index
173 rsi, rax, itable_index,
174 // outputs: method, scan temp. reg
175 method, rdi,
176 throw_icce);
177
178 // method (rbx): Method*
179 // rcx: receiver
180
181 #ifdef ASSERT
182 if (DebugVtables) {
183 Label L1;
184 __ cmpptr(method, (int32_t)NULL_WORD);
185 __ jcc(Assembler::equal, L1);
186 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
187 __ jcc(Assembler::notZero, L1);
188 __ stop("Method* is null");
189 __ bind(L1);
190 }
191 #endif // ASSERT
192
193 address ame_addr = __ pc();
194 __ jmp(Address(method, Method::from_compiled_offset()));
195
196 __ bind(throw_icce);
197 __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));
198 masm->flush();
199
200 if (PrintMiscellaneous && (WizardMode || Verbose)) {
201 tty->print_cr("itable #%d at " PTR_FORMAT "[%d] left over: %d",
202 itable_index, p2i(s->entry_point()),
203 (int)(s->code_end() - s->entry_point()),
204 (int)(s->code_end() - __ pc()));
205 }
206 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
207 // shut the door on sizing bugs
208 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
209 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
210
211 s->set_exception_points(npe_addr, ame_addr);
212 return s;
213 }
214
215
216
217 int VtableStub::pd_code_size_limit(bool is_vtable_stub) {
218 if (is_vtable_stub) {
219 // Vtable stub size
220 return (DebugVtables ? 210 : 16) + (CountCompiledCalls ? 6 : 0);
221 } else {
222 // Itable stub size
223 return (DebugVtables ? 256 : 66) + (CountCompiledCalls ? 6 : 0);
224 }
225 // In order to tune these parameters, run the JVM with VM options
226 // +PrintMiscellaneous and +WizardMode to see information about
227 // actual itable stubs. Look for lines like this:
228 // itable #1 at 0x5551212[65] left over: 3
229 // Reduce the constants so that the "left over" number is >=3
230 // for the common cases.
231 // Do not aim at a left-over number of zero, because a
232 // large vtable or itable index (> 16) will require a 32-bit
233 // immediate displacement instead of an 8-bit one.
234 //
235 // The JVM98 app. _202_jess has a megamorphic interface call.
236 // The itable code looks like this:
237 // Decoding VtableStub itbl[1]@1
238 // mov 0x4(%ecx),%esi
239 // mov 0xe8(%esi),%edi
240 // lea 0x130(%esi,%edi,4),%edi
241 // add $0x7,%edi
242 // and $0xfffffff8,%edi
243 // lea 0x4(%esi),%esi
244 // mov (%edi),%ebx
245 // cmp %ebx,%eax
246 // je success
247 // loop:
248 // test %ebx,%ebx
249 // je throw_icce
250 // add $0x8,%edi
251 // mov (%edi),%ebx
252 // cmp %ebx,%eax
253 // jne loop
254 // success:
255 // mov 0x4(%edi),%edi
256 // mov (%esi,%edi,1),%ebx
257 // jmp *0x44(%ebx)
258 // throw_icce:
259 // jmp throw_ICCE_entry
260 }
261
262 int VtableStub::pd_code_alignment() {
263 return wordSize;
264 }