jdk-sandbox: comparison src/hotspot/share/code/dependencies.hpp

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-:4ebc2e2fb97c
+:71c04702a3d5
+/*
+* Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+* or visit www.oracle.com if you need additional information or have any
+* questions.
+*
+*/
+#ifndef SHARE_VM_CODE_DEPENDENCIES_HPP
+#define SHARE_VM_CODE_DEPENDENCIES_HPP
+#include "ci/ciCallSite.hpp"
+#include "ci/ciKlass.hpp"
+#include "ci/ciMethodHandle.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "code/compressedStream.hpp"
+#include "code/nmethod.hpp"
+#include "memory/resourceArea.hpp"
+#include "utilities/growableArray.hpp"
+#include "utilities/hashtable.hpp"
+//** Dependencies represent assertions (approximate invariants) within
+// the runtime system, e.g. class hierarchy changes.  An example is an
+// assertion that a given method is not overridden; another example is
+// that a type has only one concrete subtype.  Compiled code which
+// relies on such assertions must be discarded if they are overturned
+// by changes in the runtime system.  We can think of these assertions
+// as approximate invariants, because we expect them to be overturned
+// very infrequently.  We are willing to perform expensive recovery
+// operations when they are overturned.  The benefit, of course, is
+// performing optimistic optimizations (!) on the object code.
+//
+// Changes in the class hierarchy due to dynamic linking or
+// class evolution can violate dependencies.  There is enough
+// indexing between classes and nmethods to make dependency
+// checking reasonably efficient.
+class ciEnv;
+class nmethod;
+class OopRecorder;
+class xmlStream;
+class CompileLog;
+class DepChange;
+class   KlassDepChange;
+class   CallSiteDepChange;
+class NoSafepointVerifier;
+class Dependencies: public ResourceObj {
+public:
+// Note: In the comments on dependency types, most uses of the terms
+// subtype and supertype are used in a "non-strict" or "inclusive"
+// sense, and are starred to remind the reader of this fact.
+// Strict uses of the terms use the word "proper".
+//
+// Specifically, every class is its own subtype* and supertype*.
+// (This trick is easier than continually saying things like "Y is a
+// subtype of X or X itself".)
+//
+// Sometimes we write X > Y to mean X is a proper supertype of Y.
+// The notation X > {Y, Z} means X has proper subtypes Y, Z.
+// The notation X.m > Y means that Y inherits m from X, while
+// X.m > Y.m means Y overrides X.m.  A star denotes abstractness,
+// as *I > A, meaning (abstract) interface I is a super type of A,
+// or A.*m > B.m, meaning B.m implements abstract method A.m.
+//
+// In this module, the terms "subtype" and "supertype" refer to
+// Java-level reference type conversions, as detected by
+// "instanceof" and performed by "checkcast" operations.  The method
+// Klass::is_subtype_of tests these relations.  Note that "subtype"
+// is richer than "subclass" (as tested by Klass::is_subclass_of),
+// since it takes account of relations involving interface and array
+// types.
+//
+// To avoid needless complexity, dependencies involving array types
+// are not accepted.  If you need to make an assertion about an
+// array type, make the assertion about its corresponding element
+// types.  Any assertion that might change about an array type can
+// be converted to an assertion about its element type.
+//
+// Most dependencies are evaluated over a "context type" CX, which
+// stands for the set Subtypes(CX) of every Java type that is a subtype*
+// of CX.  When the system loads a new class or interface N, it is
+// responsible for re-evaluating changed dependencies whose context
+// type now includes N, that is, all super types of N.
+//
+enum DepType {
+end_marker = 0,
+// An 'evol' dependency simply notes that the contents of the
+// method were used.  If it evolves (is replaced), the nmethod
+// must be recompiled.  No other dependencies are implied.
+evol_method,
+FIRST_TYPE = evol_method,
+// A context type CX is a leaf it if has no proper subtype.
+leaf_type,
+// An abstract class CX has exactly one concrete subtype CC.
+abstract_with_unique_concrete_subtype,
+// The type CX is purely abstract, with no concrete subtype* at all.
+abstract_with_no_concrete_subtype,
+// The concrete CX is free of concrete proper subtypes.
+concrete_with_no_concrete_subtype,
+// Given a method M1 and a context class CX, the set MM(CX, M1) of
+// "concrete matching methods" in CX of M1 is the set of every
+// concrete M2 for which it is possible to create an invokevirtual
+// or invokeinterface call site that can reach either M1 or M2.
+// That is, M1 and M2 share a name, signature, and vtable index.
+// We wish to notice when the set MM(CX, M1) is just {M1}, or
+// perhaps a set of two {M1,M2}, and issue dependencies on this.
+// The set MM(CX, M1) can be computed by starting with any matching
+// concrete M2 that is inherited into CX, and then walking the
+// subtypes* of CX looking for concrete definitions.
+// The parameters to this dependency are the method M1 and the
+// context class CX.  M1 must be either inherited in CX or defined
+// in a subtype* of CX.  It asserts that MM(CX, M1) is no greater
+// than {M1}.
+unique_concrete_method,       // one unique concrete method under CX
+// An "exclusive" assertion concerns two methods or subtypes, and
+// declares that there are at most two (or perhaps later N>2)
+// specific items that jointly satisfy the restriction.
+// We list all items explicitly rather than just giving their
+// count, for robustness in the face of complex schema changes.
+// A context class CX (which may be either abstract or concrete)
+// has two exclusive concrete subtypes* C1, C2 if every concrete
+// subtype* of CX is either C1 or C2.  Note that if neither C1 or C2
+// are equal to CX, then CX itself must be abstract.  But it is
+// also possible (for example) that C1 is CX (a concrete class)
+// and C2 is a proper subtype of C1.
+abstract_with_exclusive_concrete_subtypes_2,
+// This dependency asserts that MM(CX, M1) is no greater than {M1,M2}.
+exclusive_concrete_methods_2,
+// This dependency asserts that no instances of class or it's
+// subclasses require finalization registration.
+no_finalizable_subclasses,
+// This dependency asserts when the CallSite.target value changed.
+call_site_target_value,
+TYPE_LIMIT
+};
+enum {
+LG2_TYPE_LIMIT = 4,  // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT))
+// handy categorizations of dependency types:
+all_types           = ((1 << TYPE_LIMIT) - 1) & ((~0u) << FIRST_TYPE),
+non_klass_types     = (1 << call_site_target_value),
+klass_types         = all_types & ~non_klass_types,
+non_ctxk_types      = (1 << evol_method) | (1 << call_site_target_value),
+implicit_ctxk_types = 0,
+explicit_ctxk_types = all_types & ~(non_ctxk_types | implicit_ctxk_types),
+max_arg_count = 3,   // current maximum number of arguments (incl. ctxk)
+// A "context type" is a class or interface that
+// provides context for evaluating a dependency.
+// When present, it is one of the arguments (dep_context_arg).
+//
+// If a dependency does not have a context type, there is a
+// default context, depending on the type of the dependency.
+// This bit signals that a default context has been compressed away.
+default_context_type_bit = (1<<LG2_TYPE_LIMIT)
+};
+static const char* dep_name(DepType dept);
+static int         dep_args(DepType dept);
+static bool is_klass_type(           DepType dept) { return dept_in_mask(dept, klass_types        ); }
+static bool has_explicit_context_arg(DepType dept) { return dept_in_mask(dept, explicit_ctxk_types); }
+static bool has_implicit_context_arg(DepType dept) { return dept_in_mask(dept, implicit_ctxk_types); }
+static int           dep_context_arg(DepType dept) { return has_explicit_context_arg(dept) ? 0 : -1; }
+static int  dep_implicit_context_arg(DepType dept) { return has_implicit_context_arg(dept) ? 0 : -1; }
+static void check_valid_dependency_type(DepType dept);
+#if INCLUDE_JVMCI
+// A Metadata* or object value recorded in an OopRecorder
+class DepValue VALUE_OBJ_CLASS_SPEC {
+private:
+// Unique identifier of the value within the associated OopRecorder that
+// encodes both the category of the value (0: invalid, positive: metadata, negative: object)
+// and the index within a category specific array (metadata: index + 1, object: -(index + 1))
+int _id;
+public:
+DepValue() : _id(0) {}
+DepValue(OopRecorder* rec, Metadata* metadata, DepValue* candidate = NULL) {
+assert(candidate == NULL || candidate->is_metadata(), "oops");
+if (candidate != NULL && candidate->as_metadata(rec) == metadata) {
+_id = candidate->_id;
+} else {
+_id = rec->find_index(metadata) + 1;
+}
+}
+DepValue(OopRecorder* rec, jobject obj, DepValue* candidate = NULL) {
+assert(candidate == NULL || candidate->is_object(), "oops");
+if (candidate != NULL && candidate->as_object(rec) == obj) {
+_id = candidate->_id;
+} else {
+_id = -(rec->find_index(obj) + 1);
+}
+}
+// Used to sort values in ascending order of index() with metadata values preceding object values
+int sort_key() const { return -_id; }
+bool operator == (const DepValue& other) const   { return other._id == _id; }
+bool is_valid() const             { return _id != 0; }
+int  index() const                { assert(is_valid(), "oops"); return _id < 0 ? -(_id + 1) : _id - 1; }
+bool is_metadata() const          { assert(is_valid(), "oops"); return _id > 0; }
+bool is_object() const            { assert(is_valid(), "oops"); return _id < 0; }
+Metadata*  as_metadata(OopRecorder* rec) const    { assert(is_metadata(), "oops"); return rec->metadata_at(index()); }
+Klass*     as_klass(OopRecorder* rec) const       { assert(as_metadata(rec)->is_klass(), "oops"); return (Klass*) as_metadata(rec); }
+Method*    as_method(OopRecorder* rec) const      { assert(as_metadata(rec)->is_method(), "oops"); return (Method*) as_metadata(rec); }
+jobject    as_object(OopRecorder* rec) const      { assert(is_object(), "oops"); return rec->oop_at(index()); }
+};
+#endif // INCLUDE_JVMCI
+private:
+// State for writing a new set of dependencies:
+GrowableArray<int>*       _dep_seen;  // (seen[h->ident] & (1<<dept))
+GrowableArray<ciBaseObject*>*  _deps[TYPE_LIMIT];
+#if INCLUDE_JVMCI
+bool _using_dep_values;
+GrowableArray<DepValue>*  _dep_values[TYPE_LIMIT];
+#endif
+static const char* _dep_name[TYPE_LIMIT];
+static int         _dep_args[TYPE_LIMIT];
+static bool dept_in_mask(DepType dept, int mask) {
+return (int)dept >= 0 && dept < TYPE_LIMIT && ((1<<dept) & mask) != 0;
+}
+bool note_dep_seen(int dept, ciBaseObject* x) {
+assert(dept < BitsPerInt, "oob");
+int x_id = x->ident();
+assert(_dep_seen != NULL, "deps must be writable");
+int seen = _dep_seen->at_grow(x_id, 0);
+_dep_seen->at_put(x_id, seen | (1<<dept));
+// return true if we've already seen dept/x
+return (seen & (1<<dept)) != 0;
+}
+#if INCLUDE_JVMCI
+bool note_dep_seen(int dept, DepValue x) {
+assert(dept < BitsPerInt, "oops");
+// place metadata deps at even indexes, object deps at odd indexes
+int x_id = x.is_metadata() ? x.index() * 2 : (x.index() * 2) + 1;
+assert(_dep_seen != NULL, "deps must be writable");
+int seen = _dep_seen->at_grow(x_id, 0);
+_dep_seen->at_put(x_id, seen | (1<<dept));
+// return true if we've already seen dept/x
+return (seen & (1<<dept)) != 0;
+}
+#endif
+bool maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
+int ctxk_i, ciKlass* ctxk);
+#if INCLUDE_JVMCI
+bool maybe_merge_ctxk(GrowableArray<DepValue>* deps,
+int ctxk_i, DepValue ctxk);
+#endif
+void sort_all_deps();
+size_t estimate_size_in_bytes();
+// Initialize _deps, etc.
+void initialize(ciEnv* env);
+// State for making a new set of dependencies:
+OopRecorder* _oop_recorder;
+// Logging support
+CompileLog* _log;
+address  _content_bytes;  // everything but the oop references, encoded
+size_t   _size_in_bytes;
+public:
+// Make a new empty dependencies set.
+Dependencies(ciEnv* env) {
+initialize(env);
+}
+#if INCLUDE_JVMCI
+Dependencies(Arena* arena, OopRecorder* oop_recorder, CompileLog* log);
+#endif
+private:
+// Check for a valid context type.
+// Enforce the restriction against array types.
+static void check_ctxk(ciKlass* ctxk) {
+assert(ctxk->is_instance_klass(), "java types only");
+}
+static void check_ctxk_concrete(ciKlass* ctxk) {
+assert(is_concrete_klass(ctxk->as_instance_klass()), "must be concrete");
+}
+static void check_ctxk_abstract(ciKlass* ctxk) {
+check_ctxk(ctxk);
+assert(!is_concrete_klass(ctxk->as_instance_klass()), "must be abstract");
+}
+void assert_common_1(DepType dept, ciBaseObject* x);
+void assert_common_2(DepType dept, ciBaseObject* x0, ciBaseObject* x1);
+void assert_common_3(DepType dept, ciKlass* ctxk, ciBaseObject* x1, ciBaseObject* x2);
+public:
+// Adding assertions to a new dependency set at compile time:
+void assert_evol_method(ciMethod* m);
+void assert_leaf_type(ciKlass* ctxk);
+void assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck);
+void assert_abstract_with_no_concrete_subtype(ciKlass* ctxk);
+void assert_concrete_with_no_concrete_subtype(ciKlass* ctxk);
+void assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm);
+void assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2);
+void assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2);
+void assert_has_no_finalizable_subclasses(ciKlass* ctxk);
+void assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle);
+#if INCLUDE_JVMCI
+private:
+static void check_ctxk(Klass* ctxk) {
+assert(ctxk->is_instance_klass(), "java types only");
+}
+static void check_ctxk_abstract(Klass* ctxk) {
+check_ctxk(ctxk);
+assert(ctxk->is_abstract(), "must be abstract");
+}
+void assert_common_1(DepType dept, DepValue x);
+void assert_common_2(DepType dept, DepValue x0, DepValue x1);
+public:
+void assert_evol_method(Method* m);
+void assert_has_no_finalizable_subclasses(Klass* ctxk);
+void assert_leaf_type(Klass* ctxk);
+void assert_unique_concrete_method(Klass* ctxk, Method* uniqm);
+void assert_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck);
+void assert_call_site_target_value(oop callSite, oop methodHandle);
+#endif // INCLUDE_JVMCI
+// Define whether a given method or type is concrete.
+// These methods define the term "concrete" as used in this module.
+// For this module, an "abstract" class is one which is non-concrete.
+//
+// Future optimizations may allow some classes to remain
+// non-concrete until their first instantiation, and allow some
+// methods to remain non-concrete until their first invocation.
+// In that case, there would be a middle ground between concrete
+// and abstract (as defined by the Java language and VM).
+static bool is_concrete_klass(Klass* k);    // k is instantiable
+static bool is_concrete_method(Method* m, Klass* k);  // m is invocable
+static Klass* find_finalizable_subclass(Klass* k);
+// These versions of the concreteness queries work through the CI.
+// The CI versions are allowed to skew sometimes from the VM
+// (oop-based) versions.  The cost of such a difference is a
+// (safely) aborted compilation, or a deoptimization, or a missed
+// optimization opportunity.
+//
+// In order to prevent spurious assertions, query results must
+// remain stable within any single ciEnv instance.  (I.e., they must
+// not go back into the VM to get their value; they must cache the
+// bit in the CI, either eagerly or lazily.)
+static bool is_concrete_klass(ciInstanceKlass* k); // k appears instantiable
+static bool has_finalizable_subclass(ciInstanceKlass* k);
+// As a general rule, it is OK to compile under the assumption that
+// a given type or method is concrete, even if it at some future
+// point becomes abstract.  So dependency checking is one-sided, in
+// that it permits supposedly concrete classes or methods to turn up
+// as really abstract.  (This shouldn't happen, except during class
+// evolution, but that's the logic of the checking.)  However, if a
+// supposedly abstract class or method suddenly becomes concrete, a
+// dependency on it must fail.
+// Checking old assertions at run-time (in the VM only):
+static Klass* check_evol_method(Method* m);
+static Klass* check_leaf_type(Klass* ctxk);
+static Klass* check_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck,
+KlassDepChange* changes = NULL);
+static Klass* check_abstract_with_no_concrete_subtype(Klass* ctxk,
+KlassDepChange* changes = NULL);
+static Klass* check_concrete_with_no_concrete_subtype(Klass* ctxk,
+KlassDepChange* changes = NULL);
+static Klass* check_unique_concrete_method(Klass* ctxk, Method* uniqm,
+KlassDepChange* changes = NULL);
+static Klass* check_abstract_with_exclusive_concrete_subtypes(Klass* ctxk, Klass* k1, Klass* k2,
+KlassDepChange* changes = NULL);
+static Klass* check_exclusive_concrete_methods(Klass* ctxk, Method* m1, Method* m2,
+KlassDepChange* changes = NULL);
+static Klass* check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes = NULL);
+static Klass* check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes = NULL);
+// A returned Klass* is NULL if the dependency assertion is still
+// valid.  A non-NULL Klass* is a 'witness' to the assertion
+// failure, a point in the class hierarchy where the assertion has
+// been proven false.  For example, if check_leaf_type returns
+// non-NULL, the value is a subtype of the supposed leaf type.  This
+// witness value may be useful for logging the dependency failure.
+// Note that, when a dependency fails, there may be several possible
+// witnesses to the failure.  The value returned from the check_foo
+// method is chosen arbitrarily.
+// The 'changes' value, if non-null, requests a limited spot-check
+// near the indicated recent changes in the class hierarchy.
+// It is used by DepStream::spot_check_dependency_at.
+// Detecting possible new assertions:
+static Klass*    find_unique_concrete_subtype(Klass* ctxk);
+static Method*   find_unique_concrete_method(Klass* ctxk, Method* m);
+static int       find_exclusive_concrete_subtypes(Klass* ctxk, int klen, Klass* k[]);
+// Create the encoding which will be stored in an nmethod.
+void encode_content_bytes();
+address content_bytes() {
+assert(_content_bytes != NULL, "encode it first");
+return _content_bytes;
+}
+size_t size_in_bytes() {
+assert(_content_bytes != NULL, "encode it first");
+return _size_in_bytes;
+}
+OopRecorder* oop_recorder() { return _oop_recorder; }
+CompileLog*  log()          { return _log; }
+void copy_to(nmethod* nm);
+void log_all_dependencies();
+void log_dependency(DepType dept, GrowableArray<ciBaseObject*>* args) {
+ResourceMark rm;
+int argslen = args->length();
+write_dependency_to(log(), dept, args);
+guarantee(argslen == args->length(),
+"args array cannot grow inside nested ResoureMark scope");
+}
+void log_dependency(DepType dept,
+ciBaseObject* x0,
+ciBaseObject* x1 = NULL,
+ciBaseObject* x2 = NULL) {
+if (log() == NULL) {
+return;
+}
+ResourceMark rm;
+GrowableArray<ciBaseObject*>* ciargs =
+new GrowableArray<ciBaseObject*>(dep_args(dept));
+assert (x0 != NULL, "no log x0");
+ciargs->push(x0);
+if (x1 != NULL) {
+ciargs->push(x1);
+}
+if (x2 != NULL) {
+ciargs->push(x2);
+}
+assert(ciargs->length() == dep_args(dept), "");
+log_dependency(dept, ciargs);
+}
+class DepArgument : public ResourceObj {
+private:
+bool  _is_oop;
+bool  _valid;
+void* _value;
+public:
+DepArgument() : _is_oop(false), _value(NULL), _valid(false) {}
+DepArgument(oop v): _is_oop(true), _value(v), _valid(true) {}
+DepArgument(Metadata* v): _is_oop(false), _value(v), _valid(true) {}
+bool is_null() const               { return _value == NULL; }
+bool is_oop() const                { return _is_oop; }
+bool is_metadata() const           { return !_is_oop; }
+bool is_klass() const              { return is_metadata() && metadata_value()->is_klass(); }
+bool is_method() const              { return is_metadata() && metadata_value()->is_method(); }
+oop oop_value() const              { assert(_is_oop && _valid, "must be"); return (oop) _value; }
+Metadata* metadata_value() const { assert(!_is_oop && _valid, "must be"); return (Metadata*) _value; }
+};
+static void print_dependency(DepType dept,
+GrowableArray<DepArgument>* args,
+Klass* witness = NULL, outputStream* st = tty);
+private:
+// helper for encoding common context types as zero:
+static ciKlass* ctxk_encoded_as_null(DepType dept, ciBaseObject* x);
+static Klass* ctxk_encoded_as_null(DepType dept, Metadata* x);
+static void write_dependency_to(CompileLog* log,
+DepType dept,
+GrowableArray<ciBaseObject*>* args,
+Klass* witness = NULL);
+static void write_dependency_to(CompileLog* log,
+DepType dept,
+GrowableArray<DepArgument>* args,
+Klass* witness = NULL);
+static void write_dependency_to(xmlStream* xtty,
+DepType dept,
+GrowableArray<DepArgument>* args,
+Klass* witness = NULL);
+public:
+// Use this to iterate over an nmethod's dependency set.
+// Works on new and old dependency sets.
+// Usage:
+//
+// ;
+// Dependencies::DepType dept;
+// for (Dependencies::DepStream deps(nm); deps.next(); ) {
+//   ...
+// }
+//
+// The caller must be in the VM, since oops are not wrapped in handles.
+class DepStream {
+private:
+nmethod*              _code;   // null if in a compiler thread
+Dependencies*         _deps;   // null if not in a compiler thread
+CompressedReadStream  _bytes;
+#ifdef ASSERT
+size_t                _byte_limit;
+#endif
+// iteration variables:
+DepType               _type;
+int                   _xi[max_arg_count+1];
+void initial_asserts(size_t byte_limit) NOT_DEBUG({});
+inline Metadata* recorded_metadata_at(int i);
+inline oop recorded_oop_at(int i);
+Klass* check_klass_dependency(KlassDepChange* changes);
+Klass* check_call_site_dependency(CallSiteDepChange* changes);
+void trace_and_log_witness(Klass* witness);
+public:
+DepStream(Dependencies* deps)
+: _deps(deps),
+_code(NULL),
+_bytes(deps->content_bytes())
+{
+initial_asserts(deps->size_in_bytes());
+}
+DepStream(nmethod* code)
+: _deps(NULL),
+_code(code),
+_bytes(code->dependencies_begin())
+{
+initial_asserts(code->dependencies_size());
+}
+bool next();
+DepType type()               { return _type; }
+bool is_oop_argument(int i)  { return type() == call_site_target_value; }
+uintptr_t get_identifier(int i);
+int argument_count()         { return dep_args(type()); }
+int argument_index(int i)    { assert(0 <= i && i < argument_count(), "oob");
+return _xi[i]; }
+Metadata* argument(int i);     // => recorded_oop_at(argument_index(i))
+oop argument_oop(int i);         // => recorded_oop_at(argument_index(i))
+Klass* context_type();
+bool is_klass_type()         { return Dependencies::is_klass_type(type()); }
+Method* method_argument(int i) {
+Metadata* x = argument(i);
+assert(x->is_method(), "type");
+return (Method*) x;
+}
+Klass* type_argument(int i) {
+Metadata* x = argument(i);
+assert(x->is_klass(), "type");
+return (Klass*) x;
+}
+// The point of the whole exercise:  Is this dep still OK?
+Klass* check_dependency() {
+Klass* result = check_klass_dependency(NULL);
+if (result != NULL)  return result;
+return check_call_site_dependency(NULL);
+}
+// A lighter version:  Checks only around recent changes in a class
+// hierarchy.  (See Universe::flush_dependents_on.)
+Klass* spot_check_dependency_at(DepChange& changes);
+// Log the current dependency to xtty or compilation log.
+void log_dependency(Klass* witness = NULL);
+// Print the current dependency to tty.
+void print_dependency(Klass* witness = NULL, bool verbose = false, outputStream* st = tty);
+};
+friend class Dependencies::DepStream;
+static void print_statistics() PRODUCT_RETURN;
+};
+class DependencySignature : public ResourceObj {
+private:
+int                   _args_count;
+uintptr_t             _argument_hash[Dependencies::max_arg_count];
+Dependencies::DepType _type;
+public:
+DependencySignature(Dependencies::DepStream& dep) {
+_args_count = dep.argument_count();
+_type = dep.type();
+for (int i = 0; i < _args_count; i++) {
+_argument_hash[i] = dep.get_identifier(i);
+}
+}
+static bool     equals(DependencySignature const& s1, DependencySignature const& s2);
+static unsigned hash  (DependencySignature const& s1) { return s1.arg(0) >> 2; }
+int args_count()             const { return _args_count; }
+uintptr_t arg(int idx)       const { return _argument_hash[idx]; }
+Dependencies::DepType type() const { return _type; }
+};
+// Every particular DepChange is a sub-class of this class.
+class DepChange : public StackObj {
+public:
+// What kind of DepChange is this?
+virtual bool is_klass_change()     const { return false; }
+virtual bool is_call_site_change() const { return false; }
+virtual void mark_for_deoptimization(nmethod* nm) = 0;
+// Subclass casting with assertions.
+KlassDepChange*    as_klass_change() {
+assert(is_klass_change(), "bad cast");
+return (KlassDepChange*) this;
+}
+CallSiteDepChange* as_call_site_change() {
+assert(is_call_site_change(), "bad cast");
+return (CallSiteDepChange*) this;
+}
+void print();
+public:
+enum ChangeType {
+NO_CHANGE = 0,              // an uninvolved klass
+Change_new_type,            // a newly loaded type
+Change_new_sub,             // a super with a new subtype
+Change_new_impl,            // an interface with a new implementation
+CHANGE_LIMIT,
+Start_Klass = CHANGE_LIMIT  // internal indicator for ContextStream
+};
+// Usage:
+// for (DepChange::ContextStream str(changes); str.next(); ) {
+//   Klass* k = str.klass();
+//   switch (str.change_type()) {
+//     ...
+//   }
+// }
+class ContextStream : public StackObj {
+private:
+DepChange&  _changes;
+friend class DepChange;
+// iteration variables:
+ChangeType  _change_type;
+Klass*      _klass;
+Array<Klass*>* _ti_base;    // i.e., transitive_interfaces
+int         _ti_index;
+int         _ti_limit;
+// start at the beginning:
+void start();
+public:
+ContextStream(DepChange& changes)
+: _changes(changes)
+{ start(); }
+ContextStream(DepChange& changes, NoSafepointVerifier& nsv)
+: _changes(changes)
+// the nsv argument makes it safe to hold oops like _klass
+{ start(); }
+bool next();
+ChangeType change_type()     { return _change_type; }
+Klass*     klass()           { return _klass; }
+};
+friend class DepChange::ContextStream;
+};
+// A class hierarchy change coming through the VM (under the Compile_lock).
+// The change is structured as a single new type with any number of supers
+// and implemented interface types.  Other than the new type, any of the
+// super types can be context types for a relevant dependency, which the
+// new type could invalidate.
+class KlassDepChange : public DepChange {
+private:
+// each change set is rooted in exactly one new type (at present):
+Klass* _new_type;
+void initialize();
+public:
+// notes the new type, marks it and all its super-types
+KlassDepChange(Klass* new_type)
+: _new_type(new_type)
+{
+initialize();
+}
+// cleans up the marks
+~KlassDepChange();
+// What kind of DepChange is this?
+virtual bool is_klass_change() const { return true; }
+virtual void mark_for_deoptimization(nmethod* nm) {
+nm->mark_for_deoptimization(/*inc_recompile_counts=*/true);
+}
+Klass* new_type() { return _new_type; }
+// involves_context(k) is true if k is new_type or any of the super types
+bool involves_context(Klass* k);
+};
+// A CallSite has changed its target.
+class CallSiteDepChange : public DepChange {
+private:
+Handle _call_site;
+Handle _method_handle;
+public:
+CallSiteDepChange(Handle call_site, Handle method_handle);
+// What kind of DepChange is this?
+virtual bool is_call_site_change() const { return true; }
+virtual void mark_for_deoptimization(nmethod* nm) {
+nm->mark_for_deoptimization(/*inc_recompile_counts=*/false);
+}
+oop call_site()     const { return _call_site();     }
+oop method_handle() const { return _method_handle(); }
+};
+#endif // SHARE_VM_CODE_DEPENDENCIES_HPP

changeset 47216	71c04702a3d5
parent 46329	53ccc37bda19
child 48299	e8f5fc8f5f67