1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/code/dependencies.hpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,651 @@
1.4 +/*
1.5 + * Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#ifndef SHARE_VM_CODE_DEPENDENCIES_HPP
1.29 +#define SHARE_VM_CODE_DEPENDENCIES_HPP
1.30 +
1.31 +#include "ci/ciCallSite.hpp"
1.32 +#include "ci/ciKlass.hpp"
1.33 +#include "ci/ciMethodHandle.hpp"
1.34 +#include "classfile/systemDictionary.hpp"
1.35 +#include "code/compressedStream.hpp"
1.36 +#include "code/nmethod.hpp"
1.37 +#include "utilities/growableArray.hpp"
1.38 +
1.39 +//** Dependencies represent assertions (approximate invariants) within
1.40 +// the runtime system, e.g. class hierarchy changes. An example is an
1.41 +// assertion that a given method is not overridden; another example is
1.42 +// that a type has only one concrete subtype. Compiled code which
1.43 +// relies on such assertions must be discarded if they are overturned
1.44 +// by changes in the runtime system. We can think of these assertions
1.45 +// as approximate invariants, because we expect them to be overturned
1.46 +// very infrequently. We are willing to perform expensive recovery
1.47 +// operations when they are overturned. The benefit, of course, is
1.48 +// performing optimistic optimizations (!) on the object code.
1.49 +//
1.50 +// Changes in the class hierarchy due to dynamic linking or
1.51 +// class evolution can violate dependencies. There is enough
1.52 +// indexing between classes and nmethods to make dependency
1.53 +// checking reasonably efficient.
1.54 +
1.55 +class ciEnv;
1.56 +class nmethod;
1.57 +class OopRecorder;
1.58 +class xmlStream;
1.59 +class CompileLog;
1.60 +class DepChange;
1.61 +class KlassDepChange;
1.62 +class CallSiteDepChange;
1.63 +class No_Safepoint_Verifier;
1.64 +
1.65 +class Dependencies: public ResourceObj {
1.66 + public:
1.67 + // Note: In the comments on dependency types, most uses of the terms
1.68 + // subtype and supertype are used in a "non-strict" or "inclusive"
1.69 + // sense, and are starred to remind the reader of this fact.
1.70 + // Strict uses of the terms use the word "proper".
1.71 + //
1.72 + // Specifically, every class is its own subtype* and supertype*.
1.73 + // (This trick is easier than continually saying things like "Y is a
1.74 + // subtype of X or X itself".)
1.75 + //
1.76 + // Sometimes we write X > Y to mean X is a proper supertype of Y.
1.77 + // The notation X > {Y, Z} means X has proper subtypes Y, Z.
1.78 + // The notation X.m > Y means that Y inherits m from X, while
1.79 + // X.m > Y.m means Y overrides X.m. A star denotes abstractness,
1.80 + // as *I > A, meaning (abstract) interface I is a super type of A,
1.81 + // or A.*m > B.m, meaning B.m implements abstract method A.m.
1.82 + //
1.83 + // In this module, the terms "subtype" and "supertype" refer to
1.84 + // Java-level reference type conversions, as detected by
1.85 + // "instanceof" and performed by "checkcast" operations. The method
1.86 + // Klass::is_subtype_of tests these relations. Note that "subtype"
1.87 + // is richer than "subclass" (as tested by Klass::is_subclass_of),
1.88 + // since it takes account of relations involving interface and array
1.89 + // types.
1.90 + //
1.91 + // To avoid needless complexity, dependencies involving array types
1.92 + // are not accepted. If you need to make an assertion about an
1.93 + // array type, make the assertion about its corresponding element
1.94 + // types. Any assertion that might change about an array type can
1.95 + // be converted to an assertion about its element type.
1.96 + //
1.97 + // Most dependencies are evaluated over a "context type" CX, which
1.98 + // stands for the set Subtypes(CX) of every Java type that is a subtype*
1.99 + // of CX. When the system loads a new class or interface N, it is
1.100 + // responsible for re-evaluating changed dependencies whose context
1.101 + // type now includes N, that is, all super types of N.
1.102 + //
1.103 + enum DepType {
1.104 + end_marker = 0,
1.105 +
1.106 + // An 'evol' dependency simply notes that the contents of the
1.107 + // method were used. If it evolves (is replaced), the nmethod
1.108 + // must be recompiled. No other dependencies are implied.
1.109 + evol_method,
1.110 + FIRST_TYPE = evol_method,
1.111 +
1.112 + // A context type CX is a leaf it if has no proper subtype.
1.113 + leaf_type,
1.114 +
1.115 + // An abstract class CX has exactly one concrete subtype CC.
1.116 + abstract_with_unique_concrete_subtype,
1.117 +
1.118 + // The type CX is purely abstract, with no concrete subtype* at all.
1.119 + abstract_with_no_concrete_subtype,
1.120 +
1.121 + // The concrete CX is free of concrete proper subtypes.
1.122 + concrete_with_no_concrete_subtype,
1.123 +
1.124 + // Given a method M1 and a context class CX, the set MM(CX, M1) of
1.125 + // "concrete matching methods" in CX of M1 is the set of every
1.126 + // concrete M2 for which it is possible to create an invokevirtual
1.127 + // or invokeinterface call site that can reach either M1 or M2.
1.128 + // That is, M1 and M2 share a name, signature, and vtable index.
1.129 + // We wish to notice when the set MM(CX, M1) is just {M1}, or
1.130 + // perhaps a set of two {M1,M2}, and issue dependencies on this.
1.131 +
1.132 + // The set MM(CX, M1) can be computed by starting with any matching
1.133 + // concrete M2 that is inherited into CX, and then walking the
1.134 + // subtypes* of CX looking for concrete definitions.
1.135 +
1.136 + // The parameters to this dependency are the method M1 and the
1.137 + // context class CX. M1 must be either inherited in CX or defined
1.138 + // in a subtype* of CX. It asserts that MM(CX, M1) is no greater
1.139 + // than {M1}.
1.140 + unique_concrete_method, // one unique concrete method under CX
1.141 +
1.142 + // An "exclusive" assertion concerns two methods or subtypes, and
1.143 + // declares that there are at most two (or perhaps later N>2)
1.144 + // specific items that jointly satisfy the restriction.
1.145 + // We list all items explicitly rather than just giving their
1.146 + // count, for robustness in the face of complex schema changes.
1.147 +
1.148 + // A context class CX (which may be either abstract or concrete)
1.149 + // has two exclusive concrete subtypes* C1, C2 if every concrete
1.150 + // subtype* of CX is either C1 or C2. Note that if neither C1 or C2
1.151 + // are equal to CX, then CX itself must be abstract. But it is
1.152 + // also possible (for example) that C1 is CX (a concrete class)
1.153 + // and C2 is a proper subtype of C1.
1.154 + abstract_with_exclusive_concrete_subtypes_2,
1.155 +
1.156 + // This dependency asserts that MM(CX, M1) is no greater than {M1,M2}.
1.157 + exclusive_concrete_methods_2,
1.158 +
1.159 + // This dependency asserts that no instances of class or it's
1.160 + // subclasses require finalization registration.
1.161 + no_finalizable_subclasses,
1.162 +
1.163 + // This dependency asserts when the CallSite.target value changed.
1.164 + call_site_target_value,
1.165 +
1.166 + TYPE_LIMIT
1.167 + };
1.168 + enum {
1.169 + LG2_TYPE_LIMIT = 4, // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT))
1.170 +
1.171 + // handy categorizations of dependency types:
1.172 + all_types = ((1 << TYPE_LIMIT) - 1) & ((-1) << FIRST_TYPE),
1.173 +
1.174 + non_klass_types = (1 << call_site_target_value),
1.175 + klass_types = all_types & ~non_klass_types,
1.176 +
1.177 + non_ctxk_types = (1 << evol_method),
1.178 + implicit_ctxk_types = (1 << call_site_target_value),
1.179 + explicit_ctxk_types = all_types & ~(non_ctxk_types | implicit_ctxk_types),
1.180 +
1.181 + max_arg_count = 3, // current maximum number of arguments (incl. ctxk)
1.182 +
1.183 + // A "context type" is a class or interface that
1.184 + // provides context for evaluating a dependency.
1.185 + // When present, it is one of the arguments (dep_context_arg).
1.186 + //
1.187 + // If a dependency does not have a context type, there is a
1.188 + // default context, depending on the type of the dependency.
1.189 + // This bit signals that a default context has been compressed away.
1.190 + default_context_type_bit = (1<<LG2_TYPE_LIMIT)
1.191 + };
1.192 +
1.193 + static const char* dep_name(DepType dept);
1.194 + static int dep_args(DepType dept);
1.195 +
1.196 + static bool is_klass_type( DepType dept) { return dept_in_mask(dept, klass_types ); }
1.197 +
1.198 + static bool has_explicit_context_arg(DepType dept) { return dept_in_mask(dept, explicit_ctxk_types); }
1.199 + static bool has_implicit_context_arg(DepType dept) { return dept_in_mask(dept, implicit_ctxk_types); }
1.200 +
1.201 + static int dep_context_arg(DepType dept) { return has_explicit_context_arg(dept) ? 0 : -1; }
1.202 + static int dep_implicit_context_arg(DepType dept) { return has_implicit_context_arg(dept) ? 0 : -1; }
1.203 +
1.204 + static void check_valid_dependency_type(DepType dept);
1.205 +
1.206 + private:
1.207 + // State for writing a new set of dependencies:
1.208 + GrowableArray<int>* _dep_seen; // (seen[h->ident] & (1<<dept))
1.209 + GrowableArray<ciBaseObject*>* _deps[TYPE_LIMIT];
1.210 +
1.211 + static const char* _dep_name[TYPE_LIMIT];
1.212 + static int _dep_args[TYPE_LIMIT];
1.213 +
1.214 + static bool dept_in_mask(DepType dept, int mask) {
1.215 + return (int)dept >= 0 && dept < TYPE_LIMIT && ((1<<dept) & mask) != 0;
1.216 + }
1.217 +
1.218 + bool note_dep_seen(int dept, ciBaseObject* x) {
1.219 + assert(dept < BitsPerInt, "oob");
1.220 + int x_id = x->ident();
1.221 + assert(_dep_seen != NULL, "deps must be writable");
1.222 + int seen = _dep_seen->at_grow(x_id, 0);
1.223 + _dep_seen->at_put(x_id, seen | (1<<dept));
1.224 + // return true if we've already seen dept/x
1.225 + return (seen & (1<<dept)) != 0;
1.226 + }
1.227 +
1.228 + bool maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
1.229 + int ctxk_i, ciKlass* ctxk);
1.230 +
1.231 + void sort_all_deps();
1.232 + size_t estimate_size_in_bytes();
1.233 +
1.234 + // Initialize _deps, etc.
1.235 + void initialize(ciEnv* env);
1.236 +
1.237 + // State for making a new set of dependencies:
1.238 + OopRecorder* _oop_recorder;
1.239 +
1.240 + // Logging support
1.241 + CompileLog* _log;
1.242 +
1.243 + address _content_bytes; // everything but the oop references, encoded
1.244 + size_t _size_in_bytes;
1.245 +
1.246 + public:
1.247 + // Make a new empty dependencies set.
1.248 + Dependencies(ciEnv* env) {
1.249 + initialize(env);
1.250 + }
1.251 +
1.252 + private:
1.253 + // Check for a valid context type.
1.254 + // Enforce the restriction against array types.
1.255 + static void check_ctxk(ciKlass* ctxk) {
1.256 + assert(ctxk->is_instance_klass(), "java types only");
1.257 + }
1.258 + static void check_ctxk_concrete(ciKlass* ctxk) {
1.259 + assert(is_concrete_klass(ctxk->as_instance_klass()), "must be concrete");
1.260 + }
1.261 + static void check_ctxk_abstract(ciKlass* ctxk) {
1.262 + check_ctxk(ctxk);
1.263 + assert(!is_concrete_klass(ctxk->as_instance_klass()), "must be abstract");
1.264 + }
1.265 +
1.266 + void assert_common_1(DepType dept, ciBaseObject* x);
1.267 + void assert_common_2(DepType dept, ciBaseObject* x0, ciBaseObject* x1);
1.268 + void assert_common_3(DepType dept, ciKlass* ctxk, ciBaseObject* x1, ciBaseObject* x2);
1.269 +
1.270 + public:
1.271 + // Adding assertions to a new dependency set at compile time:
1.272 + void assert_evol_method(ciMethod* m);
1.273 + void assert_leaf_type(ciKlass* ctxk);
1.274 + void assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck);
1.275 + void assert_abstract_with_no_concrete_subtype(ciKlass* ctxk);
1.276 + void assert_concrete_with_no_concrete_subtype(ciKlass* ctxk);
1.277 + void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm);
1.278 + void assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2);
1.279 + void assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2);
1.280 + void assert_has_no_finalizable_subclasses(ciKlass* ctxk);
1.281 + void assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle);
1.282 +
1.283 + // Define whether a given method or type is concrete.
1.284 + // These methods define the term "concrete" as used in this module.
1.285 + // For this module, an "abstract" class is one which is non-concrete.
1.286 + //
1.287 + // Future optimizations may allow some classes to remain
1.288 + // non-concrete until their first instantiation, and allow some
1.289 + // methods to remain non-concrete until their first invocation.
1.290 + // In that case, there would be a middle ground between concrete
1.291 + // and abstract (as defined by the Java language and VM).
1.292 + static bool is_concrete_klass(Klass* k); // k is instantiable
1.293 + static bool is_concrete_method(Method* m); // m is invocable
1.294 + static Klass* find_finalizable_subclass(Klass* k);
1.295 +
1.296 + // These versions of the concreteness queries work through the CI.
1.297 + // The CI versions are allowed to skew sometimes from the VM
1.298 + // (oop-based) versions. The cost of such a difference is a
1.299 + // (safely) aborted compilation, or a deoptimization, or a missed
1.300 + // optimization opportunity.
1.301 + //
1.302 + // In order to prevent spurious assertions, query results must
1.303 + // remain stable within any single ciEnv instance. (I.e., they must
1.304 + // not go back into the VM to get their value; they must cache the
1.305 + // bit in the CI, either eagerly or lazily.)
1.306 + static bool is_concrete_klass(ciInstanceKlass* k); // k appears instantiable
1.307 + static bool is_concrete_method(ciMethod* m); // m appears invocable
1.308 + static bool has_finalizable_subclass(ciInstanceKlass* k);
1.309 +
1.310 + // As a general rule, it is OK to compile under the assumption that
1.311 + // a given type or method is concrete, even if it at some future
1.312 + // point becomes abstract. So dependency checking is one-sided, in
1.313 + // that it permits supposedly concrete classes or methods to turn up
1.314 + // as really abstract. (This shouldn't happen, except during class
1.315 + // evolution, but that's the logic of the checking.) However, if a
1.316 + // supposedly abstract class or method suddenly becomes concrete, a
1.317 + // dependency on it must fail.
1.318 +
1.319 + // Checking old assertions at run-time (in the VM only):
1.320 + static Klass* check_evol_method(Method* m);
1.321 + static Klass* check_leaf_type(Klass* ctxk);
1.322 + static Klass* check_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck,
1.323 + KlassDepChange* changes = NULL);
1.324 + static Klass* check_abstract_with_no_concrete_subtype(Klass* ctxk,
1.325 + KlassDepChange* changes = NULL);
1.326 + static Klass* check_concrete_with_no_concrete_subtype(Klass* ctxk,
1.327 + KlassDepChange* changes = NULL);
1.328 + static Klass* check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1.329 + KlassDepChange* changes = NULL);
1.330 + static Klass* check_abstract_with_exclusive_concrete_subtypes(Klass* ctxk, Klass* k1, Klass* k2,
1.331 + KlassDepChange* changes = NULL);
1.332 + static Klass* check_exclusive_concrete_methods(Klass* ctxk, Method* m1, Method* m2,
1.333 + KlassDepChange* changes = NULL);
1.334 + static Klass* check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes = NULL);
1.335 + static Klass* check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes = NULL);
1.336 + // A returned Klass* is NULL if the dependency assertion is still
1.337 + // valid. A non-NULL Klass* is a 'witness' to the assertion
1.338 + // failure, a point in the class hierarchy where the assertion has
1.339 + // been proven false. For example, if check_leaf_type returns
1.340 + // non-NULL, the value is a subtype of the supposed leaf type. This
1.341 + // witness value may be useful for logging the dependency failure.
1.342 + // Note that, when a dependency fails, there may be several possible
1.343 + // witnesses to the failure. The value returned from the check_foo
1.344 + // method is chosen arbitrarily.
1.345 +
1.346 + // The 'changes' value, if non-null, requests a limited spot-check
1.347 + // near the indicated recent changes in the class hierarchy.
1.348 + // It is used by DepStream::spot_check_dependency_at.
1.349 +
1.350 + // Detecting possible new assertions:
1.351 + static Klass* find_unique_concrete_subtype(Klass* ctxk);
1.352 + static Method* find_unique_concrete_method(Klass* ctxk, Method* m);
1.353 + static int find_exclusive_concrete_subtypes(Klass* ctxk, int klen, Klass* k[]);
1.354 + static int find_exclusive_concrete_methods(Klass* ctxk, int mlen, Method* m[]);
1.355 +
1.356 + // Create the encoding which will be stored in an nmethod.
1.357 + void encode_content_bytes();
1.358 +
1.359 + address content_bytes() {
1.360 + assert(_content_bytes != NULL, "encode it first");
1.361 + return _content_bytes;
1.362 + }
1.363 + size_t size_in_bytes() {
1.364 + assert(_content_bytes != NULL, "encode it first");
1.365 + return _size_in_bytes;
1.366 + }
1.367 +
1.368 + OopRecorder* oop_recorder() { return _oop_recorder; }
1.369 + CompileLog* log() { return _log; }
1.370 +
1.371 + void copy_to(nmethod* nm);
1.372 +
1.373 + void log_all_dependencies();
1.374 + void log_dependency(DepType dept, int nargs, ciBaseObject* args[]) {
1.375 + write_dependency_to(log(), dept, nargs, args);
1.376 + }
1.377 + void log_dependency(DepType dept,
1.378 + ciBaseObject* x0,
1.379 + ciBaseObject* x1 = NULL,
1.380 + ciBaseObject* x2 = NULL) {
1.381 + if (log() == NULL) return;
1.382 + ciBaseObject* args[max_arg_count];
1.383 + args[0] = x0;
1.384 + args[1] = x1;
1.385 + args[2] = x2;
1.386 + assert(2 < max_arg_count, "");
1.387 + log_dependency(dept, dep_args(dept), args);
1.388 + }
1.389 +
1.390 + class DepArgument : public ResourceObj {
1.391 + private:
1.392 + bool _is_oop;
1.393 + bool _valid;
1.394 + void* _value;
1.395 + public:
1.396 + DepArgument() : _is_oop(false), _value(NULL), _valid(false) {}
1.397 + DepArgument(oop v): _is_oop(true), _value(v), _valid(true) {}
1.398 + DepArgument(Metadata* v): _is_oop(false), _value(v), _valid(true) {}
1.399 +
1.400 + bool is_null() const { return _value == NULL; }
1.401 + bool is_oop() const { return _is_oop; }
1.402 + bool is_metadata() const { return !_is_oop; }
1.403 + bool is_klass() const { return is_metadata() && metadata_value()->is_klass(); }
1.404 + bool is_method() const { return is_metadata() && metadata_value()->is_method(); }
1.405 +
1.406 + oop oop_value() const { assert(_is_oop && _valid, "must be"); return (oop) _value; }
1.407 + Metadata* metadata_value() const { assert(!_is_oop && _valid, "must be"); return (Metadata*) _value; }
1.408 + };
1.409 +
1.410 + static void write_dependency_to(CompileLog* log,
1.411 + DepType dept,
1.412 + int nargs, ciBaseObject* args[],
1.413 + Klass* witness = NULL);
1.414 + static void write_dependency_to(CompileLog* log,
1.415 + DepType dept,
1.416 + int nargs, DepArgument args[],
1.417 + Klass* witness = NULL);
1.418 + static void write_dependency_to(xmlStream* xtty,
1.419 + DepType dept,
1.420 + int nargs, DepArgument args[],
1.421 + Klass* witness = NULL);
1.422 + static void print_dependency(DepType dept,
1.423 + int nargs, DepArgument args[],
1.424 + Klass* witness = NULL);
1.425 +
1.426 + private:
1.427 + // helper for encoding common context types as zero:
1.428 + static ciKlass* ctxk_encoded_as_null(DepType dept, ciBaseObject* x);
1.429 +
1.430 + static Klass* ctxk_encoded_as_null(DepType dept, Metadata* x);
1.431 +
1.432 + public:
1.433 + // Use this to iterate over an nmethod's dependency set.
1.434 + // Works on new and old dependency sets.
1.435 + // Usage:
1.436 + //
1.437 + // ;
1.438 + // Dependencies::DepType dept;
1.439 + // for (Dependencies::DepStream deps(nm); deps.next(); ) {
1.440 + // ...
1.441 + // }
1.442 + //
1.443 + // The caller must be in the VM, since oops are not wrapped in handles.
1.444 + class DepStream {
1.445 + private:
1.446 + nmethod* _code; // null if in a compiler thread
1.447 + Dependencies* _deps; // null if not in a compiler thread
1.448 + CompressedReadStream _bytes;
1.449 +#ifdef ASSERT
1.450 + size_t _byte_limit;
1.451 +#endif
1.452 +
1.453 + // iteration variables:
1.454 + DepType _type;
1.455 + int _xi[max_arg_count+1];
1.456 +
1.457 + void initial_asserts(size_t byte_limit) NOT_DEBUG({});
1.458 +
1.459 + inline Metadata* recorded_metadata_at(int i);
1.460 + inline oop recorded_oop_at(int i);
1.461 +
1.462 + Klass* check_klass_dependency(KlassDepChange* changes);
1.463 + Klass* check_call_site_dependency(CallSiteDepChange* changes);
1.464 +
1.465 + void trace_and_log_witness(Klass* witness);
1.466 +
1.467 + public:
1.468 + DepStream(Dependencies* deps)
1.469 + : _deps(deps),
1.470 + _code(NULL),
1.471 + _bytes(deps->content_bytes())
1.472 + {
1.473 + initial_asserts(deps->size_in_bytes());
1.474 + }
1.475 + DepStream(nmethod* code)
1.476 + : _deps(NULL),
1.477 + _code(code),
1.478 + _bytes(code->dependencies_begin())
1.479 + {
1.480 + initial_asserts(code->dependencies_size());
1.481 + }
1.482 +
1.483 + bool next();
1.484 +
1.485 + DepType type() { return _type; }
1.486 + int argument_count() { return dep_args(type()); }
1.487 + int argument_index(int i) { assert(0 <= i && i < argument_count(), "oob");
1.488 + return _xi[i]; }
1.489 + Metadata* argument(int i); // => recorded_oop_at(argument_index(i))
1.490 + oop argument_oop(int i); // => recorded_oop_at(argument_index(i))
1.491 + Klass* context_type();
1.492 +
1.493 + bool is_klass_type() { return Dependencies::is_klass_type(type()); }
1.494 +
1.495 + Method* method_argument(int i) {
1.496 + Metadata* x = argument(i);
1.497 + assert(x->is_method(), "type");
1.498 + return (Method*) x;
1.499 + }
1.500 + Klass* type_argument(int i) {
1.501 + Metadata* x = argument(i);
1.502 + assert(x->is_klass(), "type");
1.503 + return (Klass*) x;
1.504 + }
1.505 +
1.506 + // The point of the whole exercise: Is this dep still OK?
1.507 + Klass* check_dependency() {
1.508 + Klass* result = check_klass_dependency(NULL);
1.509 + if (result != NULL) return result;
1.510 + return check_call_site_dependency(NULL);
1.511 + }
1.512 +
1.513 + // A lighter version: Checks only around recent changes in a class
1.514 + // hierarchy. (See Universe::flush_dependents_on.)
1.515 + Klass* spot_check_dependency_at(DepChange& changes);
1.516 +
1.517 + // Log the current dependency to xtty or compilation log.
1.518 + void log_dependency(Klass* witness = NULL);
1.519 +
1.520 + // Print the current dependency to tty.
1.521 + void print_dependency(Klass* witness = NULL, bool verbose = false);
1.522 + };
1.523 + friend class Dependencies::DepStream;
1.524 +
1.525 + static void print_statistics() PRODUCT_RETURN;
1.526 +};
1.527 +
1.528 +
1.529 +// Every particular DepChange is a sub-class of this class.
1.530 +class DepChange : public StackObj {
1.531 + public:
1.532 + // What kind of DepChange is this?
1.533 + virtual bool is_klass_change() const { return false; }
1.534 + virtual bool is_call_site_change() const { return false; }
1.535 +
1.536 + // Subclass casting with assertions.
1.537 + KlassDepChange* as_klass_change() {
1.538 + assert(is_klass_change(), "bad cast");
1.539 + return (KlassDepChange*) this;
1.540 + }
1.541 + CallSiteDepChange* as_call_site_change() {
1.542 + assert(is_call_site_change(), "bad cast");
1.543 + return (CallSiteDepChange*) this;
1.544 + }
1.545 +
1.546 + void print();
1.547 +
1.548 + public:
1.549 + enum ChangeType {
1.550 + NO_CHANGE = 0, // an uninvolved klass
1.551 + Change_new_type, // a newly loaded type
1.552 + Change_new_sub, // a super with a new subtype
1.553 + Change_new_impl, // an interface with a new implementation
1.554 + CHANGE_LIMIT,
1.555 + Start_Klass = CHANGE_LIMIT // internal indicator for ContextStream
1.556 + };
1.557 +
1.558 + // Usage:
1.559 + // for (DepChange::ContextStream str(changes); str.next(); ) {
1.560 + // Klass* k = str.klass();
1.561 + // switch (str.change_type()) {
1.562 + // ...
1.563 + // }
1.564 + // }
1.565 + class ContextStream : public StackObj {
1.566 + private:
1.567 + DepChange& _changes;
1.568 + friend class DepChange;
1.569 +
1.570 + // iteration variables:
1.571 + ChangeType _change_type;
1.572 + Klass* _klass;
1.573 + Array<Klass*>* _ti_base; // i.e., transitive_interfaces
1.574 + int _ti_index;
1.575 + int _ti_limit;
1.576 +
1.577 + // start at the beginning:
1.578 + void start();
1.579 +
1.580 + public:
1.581 + ContextStream(DepChange& changes)
1.582 + : _changes(changes)
1.583 + { start(); }
1.584 +
1.585 + ContextStream(DepChange& changes, No_Safepoint_Verifier& nsv)
1.586 + : _changes(changes)
1.587 + // the nsv argument makes it safe to hold oops like _klass
1.588 + { start(); }
1.589 +
1.590 + bool next();
1.591 +
1.592 + ChangeType change_type() { return _change_type; }
1.593 + Klass* klass() { return _klass; }
1.594 + };
1.595 + friend class DepChange::ContextStream;
1.596 +};
1.597 +
1.598 +
1.599 +// A class hierarchy change coming through the VM (under the Compile_lock).
1.600 +// The change is structured as a single new type with any number of supers
1.601 +// and implemented interface types. Other than the new type, any of the
1.602 +// super types can be context types for a relevant dependency, which the
1.603 +// new type could invalidate.
1.604 +class KlassDepChange : public DepChange {
1.605 + private:
1.606 + // each change set is rooted in exactly one new type (at present):
1.607 + KlassHandle _new_type;
1.608 +
1.609 + void initialize();
1.610 +
1.611 + public:
1.612 + // notes the new type, marks it and all its super-types
1.613 + KlassDepChange(KlassHandle new_type)
1.614 + : _new_type(new_type)
1.615 + {
1.616 + initialize();
1.617 + }
1.618 +
1.619 + // cleans up the marks
1.620 + ~KlassDepChange();
1.621 +
1.622 + // What kind of DepChange is this?
1.623 + virtual bool is_klass_change() const { return true; }
1.624 +
1.625 + Klass* new_type() { return _new_type(); }
1.626 +
1.627 + // involves_context(k) is true if k is new_type or any of the super types
1.628 + bool involves_context(Klass* k);
1.629 +};
1.630 +
1.631 +
1.632 +// A CallSite has changed its target.
1.633 +class CallSiteDepChange : public DepChange {
1.634 + private:
1.635 + Handle _call_site;
1.636 + Handle _method_handle;
1.637 +
1.638 + public:
1.639 + CallSiteDepChange(Handle call_site, Handle method_handle)
1.640 + : _call_site(call_site),
1.641 + _method_handle(method_handle)
1.642 + {
1.643 + assert(_call_site() ->is_a(SystemDictionary::CallSite_klass()), "must be");
1.644 + assert(_method_handle()->is_a(SystemDictionary::MethodHandle_klass()), "must be");
1.645 + }
1.646 +
1.647 + // What kind of DepChange is this?
1.648 + virtual bool is_call_site_change() const { return true; }
1.649 +
1.650 + oop call_site() const { return _call_site(); }
1.651 + oop method_handle() const { return _method_handle(); }
1.652 +};
1.653 +
1.654 +#endif // SHARE_VM_CODE_DEPENDENCIES_HPP
