Mercurial > hg > graal-compiler
view src/share/vm/code/dependencies.hpp @ 396:4d05b7cb7842
6306922: Dump dump created by +HeapDumpOnOutOfMemoryError should include stack traces for stack roots
Summary: Include stack traces of all threads in the heap dump
Reviewed-by: alanb
author | mchung |
---|---|
date | Tue, 14 Oct 2008 15:16:38 -0700 |
parents | a61af66fc99e |
children | 167c2986d91b |
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/* * Copyright 2005-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ //** Dependencies represent assertions (approximate invariants) within // the class hierarchy. 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 class hierarchy. 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 No_Safepoint_Verifier; 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, 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) & ((-1)<<FIRST_TYPE), non_ctxk_types = (1<<evol_method), ctxk_types = all_types & ~non_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 int dep_context_arg(DepType dept) { return dept_in_mask(dept, ctxk_types)? 0: -1; } private: // State for writing a new set of dependencies: GrowableArray<int>* _dep_seen; // (seen[h->ident] & (1<<dept)) GrowableArray<ciObject*>* _deps[TYPE_LIMIT]; 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, ciObject* 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; } bool maybe_merge_ctxk(GrowableArray<ciObject*>* deps, int ctxk_i, ciKlass* ctxk); 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); } 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, ciObject* x); void assert_common_2(DepType dept, ciKlass* ctxk, ciObject* x); void assert_common_3(DepType dept, ciKlass* ctxk, ciObject* x, ciObject* 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); // 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(klassOop k); // k is instantiable static bool is_concrete_method(methodOop m); // 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 is_concrete_method(ciMethod* m); // m appears invocable 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 klassOop check_evol_method(methodOop m); static klassOop check_leaf_type(klassOop ctxk); static klassOop check_abstract_with_unique_concrete_subtype(klassOop ctxk, klassOop conck, DepChange* changes = NULL); static klassOop check_abstract_with_no_concrete_subtype(klassOop ctxk, DepChange* changes = NULL); static klassOop check_concrete_with_no_concrete_subtype(klassOop ctxk, DepChange* changes = NULL); static klassOop check_unique_concrete_method(klassOop ctxk, methodOop uniqm, DepChange* changes = NULL); static klassOop check_abstract_with_exclusive_concrete_subtypes(klassOop ctxk, klassOop k1, klassOop k2, DepChange* changes = NULL); static klassOop check_exclusive_concrete_methods(klassOop ctxk, methodOop m1, methodOop m2, DepChange* changes = NULL); static klassOop check_has_no_finalizable_subclasses(klassOop ctxk, DepChange* changes = NULL); // A returned klassOop is NULL if the dependency assertion is still // valid. A non-NULL klassOop 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 klassOop find_unique_concrete_subtype(klassOop ctxk); static methodOop find_unique_concrete_method(klassOop ctxk, methodOop m); static int find_exclusive_concrete_subtypes(klassOop ctxk, int klen, klassOop k[]); static int find_exclusive_concrete_methods(klassOop ctxk, int mlen, methodOop m[]); // 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, int nargs, ciObject* args[]) { write_dependency_to(log(), dept, nargs, args); } void log_dependency(DepType dept, ciObject* x0, ciObject* x1 = NULL, ciObject* x2 = NULL) { if (log() == NULL) return; ciObject* args[max_arg_count]; args[0] = x0; args[1] = x1; args[2] = x2; assert(2 < max_arg_count, ""); log_dependency(dept, dep_args(dept), args); } static void write_dependency_to(CompileLog* log, DepType dept, int nargs, ciObject* args[], klassOop witness = NULL); static void write_dependency_to(CompileLog* log, DepType dept, int nargs, oop args[], klassOop witness = NULL); static void write_dependency_to(xmlStream* xtty, DepType dept, int nargs, oop args[], klassOop witness = NULL); static void print_dependency(DepType dept, int nargs, oop args[], klassOop witness = NULL); private: // helper for encoding common context types as zero: static ciKlass* ctxk_encoded_as_null(DepType dept, ciObject* x); static klassOop ctxk_encoded_as_null(DepType dept, oop x); 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 oop recorded_oop_at(int i); // => _code? _code->oop_at(i): *_deps->_oop_recorder->handle_at(i) klassOop check_dependency_impl(DepChange* changes); 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; } int argument_count() { return dep_args(type()); } int argument_index(int i) { assert(0 <= i && i < argument_count(), "oob"); return _xi[i]; } oop argument(int i); // => recorded_oop_at(argument_index(i)) klassOop context_type(); methodOop method_argument(int i) { oop x = argument(i); assert(x->is_method(), "type"); return (methodOop) x; } klassOop type_argument(int i) { oop x = argument(i); assert(x->is_klass(), "type"); return (klassOop) x; } // The point of the whole exercise: Is this dep is still OK? klassOop check_dependency() { return check_dependency_impl(NULL); } // A lighter version: Checks only around recent changes in a class // hierarchy. (See Universe::flush_dependents_on.) klassOop spot_check_dependency_at(DepChange& changes); // Log the current dependency to xtty or compilation log. void log_dependency(klassOop witness = NULL); // Print the current dependency to tty. void print_dependency(klassOop witness = NULL, bool verbose = false); }; friend class Dependencies::DepStream; static void print_statistics() PRODUCT_RETURN; }; // 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 DepChange : public StackObj { private: 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 }; // each change set is rooted in exactly one new type (at present): KlassHandle _new_type; void initialize(); public: // notes the new type, marks it and all its super-types DepChange(KlassHandle new_type) : _new_type(new_type) { initialize(); } // cleans up the marks ~DepChange(); klassOop new_type() { return _new_type(); } // involves_context(k) is true if k is new_type or any of the super types bool involves_context(klassOop k); // Usage: // for (DepChange::ContextStream str(changes); str.next(); ) { // klassOop k = str.klass(); // switch (str.change_type()) { // ... // } // } class ContextStream : public StackObj { private: DepChange& _changes; friend class DepChange; // iteration variables: ChangeType _change_type; klassOop _klass; objArrayOop _ti_base; // i.e., transitive_interfaces int _ti_index; int _ti_limit; // start at the beginning: void start() { klassOop new_type = _changes.new_type(); _change_type = (new_type == NULL ? NO_CHANGE: Start_Klass); _klass = new_type; _ti_base = NULL; _ti_index = 0; _ti_limit = 0; } ContextStream(DepChange& changes) : _changes(changes) { start(); } public: ContextStream(DepChange& changes, No_Safepoint_Verifier& nsv) : _changes(changes) // the nsv argument makes it safe to hold oops like _klass { start(); } bool next(); klassOop klass() { return _klass; } }; friend class DepChange::ContextStream; void print(); };