Thu, 07 Apr 2011 17:02:30 -0700
6981791: remove experimental code for JSR 292
Reviewed-by: twisti
1 /*
2 * Copyright (c) 1998, 2011, 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.
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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
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23 */
25 #include "precompiled.hpp"
26 #include "interpreter/bytecodes.hpp"
27 #include "interpreter/interpreter.hpp"
28 #include "interpreter/rewriter.hpp"
29 #include "memory/gcLocker.hpp"
30 #include "memory/oopFactory.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "oops/generateOopMap.hpp"
33 #include "oops/objArrayOop.hpp"
34 #include "oops/oop.inline.hpp"
35 #include "prims/methodComparator.hpp"
37 // Computes a CPC map (new_index -> original_index) for constant pool entries
38 // that are referred to by the interpreter at runtime via the constant pool cache.
39 // Also computes a CP map (original_index -> new_index).
40 // Marks entries in CP which require additional processing.
41 void Rewriter::compute_index_maps() {
42 const int length = _pool->length();
43 init_cp_map(length);
44 jint tag_mask = 0;
45 for (int i = 0; i < length; i++) {
46 int tag = _pool->tag_at(i).value();
47 tag_mask |= (1 << tag);
48 switch (tag) {
49 case JVM_CONSTANT_InterfaceMethodref:
50 case JVM_CONSTANT_Fieldref : // fall through
51 case JVM_CONSTANT_Methodref : // fall through
52 case JVM_CONSTANT_MethodHandle : // fall through
53 case JVM_CONSTANT_MethodType : // fall through
54 case JVM_CONSTANT_InvokeDynamic : // fall through
55 add_cp_cache_entry(i);
56 break;
57 }
58 }
60 guarantee((int)_cp_cache_map.length()-1 <= (int)((u2)-1),
61 "all cp cache indexes fit in a u2");
63 _have_invoke_dynamic = ((tag_mask & (1 << JVM_CONSTANT_InvokeDynamic)) != 0);
64 }
67 // Creates a constant pool cache given a CPC map
68 void Rewriter::make_constant_pool_cache(TRAPS) {
69 const int length = _cp_cache_map.length();
70 constantPoolCacheOop cache =
71 oopFactory::new_constantPoolCache(length, CHECK);
72 No_Safepoint_Verifier nsv;
73 cache->initialize(_cp_cache_map);
75 // Don't bother with the next pass if there is no JVM_CONSTANT_InvokeDynamic.
76 if (_have_invoke_dynamic) {
77 for (int i = 0; i < length; i++) {
78 int pool_index = cp_cache_entry_pool_index(i);
79 if (pool_index >= 0 &&
80 _pool->tag_at(pool_index).is_invoke_dynamic()) {
81 int bsm_index = _pool->invoke_dynamic_bootstrap_method_ref_index_at(pool_index);
82 assert(_pool->tag_at(bsm_index).is_method_handle(), "must be a MH constant");
83 // There is a CP cache entry holding the BSM for these calls.
84 int bsm_cache_index = cp_entry_to_cp_cache(bsm_index);
85 cache->entry_at(i)->initialize_bootstrap_method_index_in_cache(bsm_cache_index);
86 }
87 }
88 }
90 _pool->set_cache(cache);
91 cache->set_constant_pool(_pool());
92 }
96 // The new finalization semantics says that registration of
97 // finalizable objects must be performed on successful return from the
98 // Object.<init> constructor. We could implement this trivially if
99 // <init> were never rewritten but since JVMTI allows this to occur, a
100 // more complicated solution is required. A special return bytecode
101 // is used only by Object.<init> to signal the finalization
102 // registration point. Additionally local 0 must be preserved so it's
103 // available to pass to the registration function. For simplicty we
104 // require that local 0 is never overwritten so it's available as an
105 // argument for registration.
107 void Rewriter::rewrite_Object_init(methodHandle method, TRAPS) {
108 RawBytecodeStream bcs(method);
109 while (!bcs.is_last_bytecode()) {
110 Bytecodes::Code opcode = bcs.raw_next();
111 switch (opcode) {
112 case Bytecodes::_return: *bcs.bcp() = Bytecodes::_return_register_finalizer; break;
114 case Bytecodes::_istore:
115 case Bytecodes::_lstore:
116 case Bytecodes::_fstore:
117 case Bytecodes::_dstore:
118 case Bytecodes::_astore:
119 if (bcs.get_index() != 0) continue;
121 // fall through
122 case Bytecodes::_istore_0:
123 case Bytecodes::_lstore_0:
124 case Bytecodes::_fstore_0:
125 case Bytecodes::_dstore_0:
126 case Bytecodes::_astore_0:
127 THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(),
128 "can't overwrite local 0 in Object.<init>");
129 break;
130 }
131 }
132 }
135 // Rewrite a classfile-order CP index into a native-order CPC index.
136 void Rewriter::rewrite_member_reference(address bcp, int offset) {
137 address p = bcp + offset;
138 int cp_index = Bytes::get_Java_u2(p);
139 int cache_index = cp_entry_to_cp_cache(cp_index);
140 Bytes::put_native_u2(p, cache_index);
141 }
144 void Rewriter::rewrite_invokedynamic(address bcp, int offset) {
145 address p = bcp + offset;
146 assert(p[-1] == Bytecodes::_invokedynamic, "");
147 int cp_index = Bytes::get_Java_u2(p);
148 int cpc = maybe_add_cp_cache_entry(cp_index); // add lazily
149 int cpc2 = add_secondary_cp_cache_entry(cpc);
151 // Replace the trailing four bytes with a CPC index for the dynamic
152 // call site. Unlike other CPC entries, there is one per bytecode,
153 // not just one per distinct CP entry. In other words, the
154 // CPC-to-CP relation is many-to-one for invokedynamic entries.
155 // This means we must use a larger index size than u2 to address
156 // all these entries. That is the main reason invokedynamic
157 // must have a five-byte instruction format. (Of course, other JVM
158 // implementations can use the bytes for other purposes.)
159 Bytes::put_native_u4(p, constantPoolCacheOopDesc::encode_secondary_index(cpc2));
160 // Note: We use native_u4 format exclusively for 4-byte indexes.
161 }
164 // Rewrite some ldc bytecodes to _fast_aldc
165 void Rewriter::maybe_rewrite_ldc(address bcp, int offset, bool is_wide) {
166 assert((*bcp) == (is_wide ? Bytecodes::_ldc_w : Bytecodes::_ldc), "");
167 address p = bcp + offset;
168 int cp_index = is_wide ? Bytes::get_Java_u2(p) : (u1)(*p);
169 constantTag tag = _pool->tag_at(cp_index).value();
170 if (tag.is_method_handle() || tag.is_method_type()) {
171 int cache_index = cp_entry_to_cp_cache(cp_index);
172 if (is_wide) {
173 (*bcp) = Bytecodes::_fast_aldc_w;
174 assert(cache_index == (u2)cache_index, "");
175 Bytes::put_native_u2(p, cache_index);
176 } else {
177 (*bcp) = Bytecodes::_fast_aldc;
178 assert(cache_index == (u1)cache_index, "");
179 (*p) = (u1)cache_index;
180 }
181 }
182 }
185 // Rewrites a method given the index_map information
186 void Rewriter::scan_method(methodOop method) {
188 int nof_jsrs = 0;
189 bool has_monitor_bytecodes = false;
191 {
192 // We cannot tolerate a GC in this block, because we've
193 // cached the bytecodes in 'code_base'. If the methodOop
194 // moves, the bytecodes will also move.
195 No_Safepoint_Verifier nsv;
196 Bytecodes::Code c;
198 // Bytecodes and their length
199 const address code_base = method->code_base();
200 const int code_length = method->code_size();
202 int bc_length;
203 for (int bci = 0; bci < code_length; bci += bc_length) {
204 address bcp = code_base + bci;
205 int prefix_length = 0;
206 c = (Bytecodes::Code)(*bcp);
208 // Since we have the code, see if we can get the length
209 // directly. Some more complicated bytecodes will report
210 // a length of zero, meaning we need to make another method
211 // call to calculate the length.
212 bc_length = Bytecodes::length_for(c);
213 if (bc_length == 0) {
214 bc_length = Bytecodes::length_at(method, bcp);
216 // length_at will put us at the bytecode after the one modified
217 // by 'wide'. We don't currently examine any of the bytecodes
218 // modified by wide, but in case we do in the future...
219 if (c == Bytecodes::_wide) {
220 prefix_length = 1;
221 c = (Bytecodes::Code)bcp[1];
222 }
223 }
225 assert(bc_length != 0, "impossible bytecode length");
227 switch (c) {
228 case Bytecodes::_lookupswitch : {
229 #ifndef CC_INTERP
230 Bytecode_lookupswitch bc(method, bcp);
231 (*bcp) = (
232 bc.number_of_pairs() < BinarySwitchThreshold
233 ? Bytecodes::_fast_linearswitch
234 : Bytecodes::_fast_binaryswitch
235 );
236 #endif
237 break;
238 }
239 case Bytecodes::_getstatic : // fall through
240 case Bytecodes::_putstatic : // fall through
241 case Bytecodes::_getfield : // fall through
242 case Bytecodes::_putfield : // fall through
243 case Bytecodes::_invokevirtual : // fall through
244 case Bytecodes::_invokespecial : // fall through
245 case Bytecodes::_invokestatic :
246 case Bytecodes::_invokeinterface:
247 rewrite_member_reference(bcp, prefix_length+1);
248 break;
249 case Bytecodes::_invokedynamic:
250 rewrite_invokedynamic(bcp, prefix_length+1);
251 break;
252 case Bytecodes::_ldc:
253 maybe_rewrite_ldc(bcp, prefix_length+1, false);
254 break;
255 case Bytecodes::_ldc_w:
256 maybe_rewrite_ldc(bcp, prefix_length+1, true);
257 break;
258 case Bytecodes::_jsr : // fall through
259 case Bytecodes::_jsr_w : nof_jsrs++; break;
260 case Bytecodes::_monitorenter : // fall through
261 case Bytecodes::_monitorexit : has_monitor_bytecodes = true; break;
262 }
263 }
264 }
266 // Update access flags
267 if (has_monitor_bytecodes) {
268 method->set_has_monitor_bytecodes();
269 }
271 // The present of a jsr bytecode implies that the method might potentially
272 // have to be rewritten, so we run the oopMapGenerator on the method
273 if (nof_jsrs > 0) {
274 method->set_has_jsrs();
275 // Second pass will revisit this method.
276 assert(method->has_jsrs(), "");
277 }
278 }
280 // After constant pool is created, revisit methods containing jsrs.
281 methodHandle Rewriter::rewrite_jsrs(methodHandle method, TRAPS) {
282 ResolveOopMapConflicts romc(method);
283 methodHandle original_method = method;
284 method = romc.do_potential_rewrite(CHECK_(methodHandle()));
285 if (method() != original_method()) {
286 // Insert invalid bytecode into original methodOop and set
287 // interpreter entrypoint, so that a executing this method
288 // will manifest itself in an easy recognizable form.
289 address bcp = original_method->bcp_from(0);
290 *bcp = (u1)Bytecodes::_shouldnotreachhere;
291 int kind = Interpreter::method_kind(original_method);
292 original_method->set_interpreter_kind(kind);
293 }
295 // Update monitor matching info.
296 if (romc.monitor_safe()) {
297 method->set_guaranteed_monitor_matching();
298 }
300 return method;
301 }
304 void Rewriter::rewrite(instanceKlassHandle klass, TRAPS) {
305 ResourceMark rm(THREAD);
306 Rewriter rw(klass, klass->constants(), klass->methods(), CHECK);
307 // (That's all, folks.)
308 }
311 void Rewriter::rewrite(instanceKlassHandle klass, constantPoolHandle cpool, objArrayHandle methods, TRAPS) {
312 ResourceMark rm(THREAD);
313 Rewriter rw(klass, cpool, methods, CHECK);
314 // (That's all, folks.)
315 }
318 Rewriter::Rewriter(instanceKlassHandle klass, constantPoolHandle cpool, objArrayHandle methods, TRAPS)
319 : _klass(klass),
320 _pool(cpool),
321 _methods(methods)
322 {
323 assert(_pool->cache() == NULL, "constant pool cache must not be set yet");
325 // determine index maps for methodOop rewriting
326 compute_index_maps();
328 if (RegisterFinalizersAtInit && _klass->name() == vmSymbols::java_lang_Object()) {
329 bool did_rewrite = false;
330 int i = _methods->length();
331 while (i-- > 0) {
332 methodOop method = (methodOop)_methods->obj_at(i);
333 if (method->intrinsic_id() == vmIntrinsics::_Object_init) {
334 // rewrite the return bytecodes of Object.<init> to register the
335 // object for finalization if needed.
336 methodHandle m(THREAD, method);
337 rewrite_Object_init(m, CHECK);
338 did_rewrite = true;
339 break;
340 }
341 }
342 assert(did_rewrite, "must find Object::<init> to rewrite it");
343 }
345 // rewrite methods, in two passes
346 int i, len = _methods->length();
348 for (i = len; --i >= 0; ) {
349 methodOop method = (methodOop)_methods->obj_at(i);
350 scan_method(method);
351 }
353 // allocate constant pool cache, now that we've seen all the bytecodes
354 make_constant_pool_cache(CHECK);
356 for (i = len; --i >= 0; ) {
357 methodHandle m(THREAD, (methodOop)_methods->obj_at(i));
359 if (m->has_jsrs()) {
360 m = rewrite_jsrs(m, CHECK);
361 // Method might have gotten rewritten.
362 _methods->obj_at_put(i, m());
363 }
365 // Set up method entry points for compiler and interpreter.
366 m->link_method(m, CHECK);
368 #ifdef ASSERT
369 if (StressMethodComparator) {
370 static int nmc = 0;
371 for (int j = i; j >= 0 && j >= i-4; j--) {
372 if ((++nmc % 1000) == 0) tty->print_cr("Have run MethodComparator %d times...", nmc);
373 bool z = MethodComparator::methods_EMCP(m(), (methodOop)_methods->obj_at(j));
374 if (j == i && !z) {
375 tty->print("MethodComparator FAIL: "); m->print(); m->print_codes();
376 assert(z, "method must compare equal to itself");
377 }
378 }
379 }
380 #endif //ASSERT
381 }
382 }