1 /*
2 * Copyright (c) 1997, 2012, 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_32.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 ResourceMark rm;
62 CodeBuffer cb(s->entry_point(), i486_code_length);
63 MacroAssembler* masm = new MacroAssembler(&cb);
64
65 #ifndef PRODUCT
66
67 if (CountCompiledCalls) {
68 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
69 }
70 #endif /* PRODUCT */
71
72 // get receiver (need to skip return address on top of stack)
73 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
74
75 // get receiver klass
76 address npe_addr = __ pc();
77 __ movptr(rax, Address(rcx, oopDesc::klass_offset_in_bytes()));
78
79 #ifndef PRODUCT
80 if (DebugVtables) {
81 Label L;
82 // check offset vs vtable length
83 __ cmpl(Address(rax, InstanceKlass::vtable_length_offset()*wordSize), vtable_index*vtableEntry::size());
84 __ jcc(Assembler::greater, L);
85 __ movl(rbx, vtable_index);
86 __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), rcx, rbx);
87 __ bind(L);
88 }
89 #endif // PRODUCT
90
91 const Register method = rbx;
92
93 // load Method* and target address
94 __ lookup_virtual_method(rax, vtable_index, method);
95
96 if (DebugVtables) {
97 Label L;
98 __ cmpptr(method, (int32_t)NULL_WORD);
99 __ jcc(Assembler::equal, L);
100 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
101 __ jcc(Assembler::notZero, L);
102 __ stop("Vtable entry is NULL");
103 __ bind(L);
104 }
105
106 // rax,: receiver klass
107 // method (rbx): Method*
108 // rcx: receiver
109 address ame_addr = __ pc();
110 __ jmp( Address(method, Method::from_compiled_offset()));
111
112 masm->flush();
113
114 if (PrintMiscellaneous && (WizardMode || Verbose)) {
115 tty->print_cr("vtable #%d at "PTR_FORMAT"[%d] left over: %d",
116 vtable_index, s->entry_point(),
117 (int)(s->code_end() - s->entry_point()),
118 (int)(s->code_end() - __ pc()));
119 }
120 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
121 // shut the door on sizing bugs
122 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
123 assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
124
125 s->set_exception_points(npe_addr, ame_addr);
126 return s;
127 }
128
129
130 VtableStub* VtableStubs::create_itable_stub(int itable_index) {
131 // Note well: pd_code_size_limit is the absolute minimum we can get away with. If you
132 // add code here, bump the code stub size returned by pd_code_size_limit!
133 const int i486_code_length = VtableStub::pd_code_size_limit(false);
134 VtableStub* s = new(i486_code_length) VtableStub(false, itable_index);
135 ResourceMark rm;
136 CodeBuffer cb(s->entry_point(), i486_code_length);
137 MacroAssembler* masm = new MacroAssembler(&cb);
138
139 // Entry arguments:
140 // rax,: Interface
141 // rcx: Receiver
142
143 #ifndef PRODUCT
144 if (CountCompiledCalls) {
145 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
146 }
147 #endif /* PRODUCT */
148 // get receiver (need to skip return address on top of stack)
149
150 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");
151
152 // get receiver klass (also an implicit null-check)
153 address npe_addr = __ pc();
154 __ movptr(rsi, Address(rcx, oopDesc::klass_offset_in_bytes()));
155
156 // Most registers are in use; we'll use rax, rbx, rsi, rdi
157 // (If we need to make rsi, rdi callee-save, do a push/pop here.)
158 const Register method = rbx;
159 Label throw_icce;
160
161 // Get Method* and entrypoint for compiler
162 __ lookup_interface_method(// inputs: rec. class, interface, itable index
163 rsi, rax, itable_index,
164 // outputs: method, scan temp. reg
165 method, rdi,
166 throw_icce);
167
168 // method (rbx): Method*
169 // rcx: receiver
170
171 #ifdef ASSERT
172 if (DebugVtables) {
173 Label L1;
174 __ cmpptr(method, (int32_t)NULL_WORD);
175 __ jcc(Assembler::equal, L1);
176 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);
177 __ jcc(Assembler::notZero, L1);
178 __ stop("Method* is null");
179 __ bind(L1);
180 }
181 #endif // ASSERT
182
183 address ame_addr = __ pc();
184 __ jmp(Address(method, Method::from_compiled_offset()));
185
186 __ bind(throw_icce);
187 __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));
188 masm->flush();
189
190 if (PrintMiscellaneous && (WizardMode || Verbose)) {
191 tty->print_cr("itable #%d at "PTR_FORMAT"[%d] left over: %d",
192 itable_index, s->entry_point(),
193 (int)(s->code_end() - s->entry_point()),
194 (int)(s->code_end() - __ pc()));
195 }
196 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
197 // shut the door on sizing bugs
198 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
199 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
200
201 s->set_exception_points(npe_addr, ame_addr);
202 return s;
203 }
204
205
206
207 int VtableStub::pd_code_size_limit(bool is_vtable_stub) {
208 if (is_vtable_stub) {
209 // Vtable stub size
210 return (DebugVtables ? 210 : 16) + (CountCompiledCalls ? 6 : 0);
211 } else {
212 // Itable stub size
213 return (DebugVtables ? 256 : 66) + (CountCompiledCalls ? 6 : 0);
214 }
215 // In order to tune these parameters, run the JVM with VM options
216 // +PrintMiscellaneous and +WizardMode to see information about
217 // actual itable stubs. Look for lines like this:
218 // itable #1 at 0x5551212[65] left over: 3
219 // Reduce the constants so that the "left over" number is >=3
220 // for the common cases.
221 // Do not aim at a left-over number of zero, because a
222 // large vtable or itable index (> 16) will require a 32-bit
223 // immediate displacement instead of an 8-bit one.
224 //
225 // The JVM98 app. _202_jess has a megamorphic interface call.
226 // The itable code looks like this:
227 // Decoding VtableStub itbl[1]@1
228 // mov 0x4(%ecx),%esi
229 // mov 0xe8(%esi),%edi
230 // lea 0x130(%esi,%edi,4),%edi
231 // add $0x7,%edi
232 // and $0xfffffff8,%edi
233 // lea 0x4(%esi),%esi
234 // mov (%edi),%ebx
235 // cmp %ebx,%eax
236 // je success
237 // loop:
238 // test %ebx,%ebx
239 // je throw_icce
240 // add $0x8,%edi
241 // mov (%edi),%ebx
242 // cmp %ebx,%eax
243 // jne loop
244 // success:
245 // mov 0x4(%edi),%edi
246 // mov (%esi,%edi,1),%ebx
247 // jmp *0x44(%ebx)
248 // throw_icce:
249 // jmp throw_ICCE_entry
250 }
251
252 int VtableStub::pd_code_alignment() {
253 return wordSize;
254 }