Mercurial > hg > graal-compiler
view src/share/vm/prims/jvmtiRedefineClasses.hpp @ 20262:76b588255908
8035746: Add missing Klass::oop_is_instanceClassLoader() function
Reviewed-by: mgerdin, coleenp
author | stefank |
---|---|
date | Thu, 27 Feb 2014 10:36:50 +0100 |
parents | 825e6cb66923 |
children | 50054b63f0aa |
line wrap: on
line source
/* * Copyright (c) 2003, 2013, 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_PRIMS_JVMTIREDEFINECLASSES_HPP #define SHARE_VM_PRIMS_JVMTIREDEFINECLASSES_HPP #include "jvmtifiles/jvmtiEnv.hpp" #include "memory/oopFactory.hpp" #include "memory/resourceArea.hpp" #include "oops/objArrayKlass.hpp" #include "oops/objArrayOop.hpp" #include "prims/jvmtiRedefineClassesTrace.hpp" #include "runtime/vm_operations.hpp" // Introduction: // // The RedefineClasses() API is used to change the definition of one or // more classes. While the API supports redefining more than one class // in a single call, in general, the API is discussed in the context of // changing the definition of a single current class to a single new // class. For clarity, the current class is will always be called // "the_class" and the new class will always be called "scratch_class". // // The name "the_class" is used because there is only one structure // that represents a specific class; redefinition does not replace the // structure, but instead replaces parts of the structure. The name // "scratch_class" is used because the structure that represents the // new definition of a specific class is simply used to carry around // the parts of the new definition until they are used to replace the // appropriate parts in the_class. Once redefinition of a class is // complete, scratch_class is thrown away. // // // Implementation Overview: // // The RedefineClasses() API is mostly a wrapper around the VM op that // does the real work. The work is split in varying degrees between // doit_prologue(), doit() and doit_epilogue(). // // 1) doit_prologue() is called by the JavaThread on the way to a // safepoint. It does parameter verification and loads scratch_class // which involves: // - parsing the incoming class definition using the_class' class // loader and security context // - linking scratch_class // - merging constant pools and rewriting bytecodes as needed // for the merged constant pool // - verifying the bytecodes in scratch_class // - setting up the constant pool cache and rewriting bytecodes // as needed to use the cache // - finally, scratch_class is compared to the_class to verify // that it is a valid replacement class // - if everything is good, then scratch_class is saved in an // instance field in the VM operation for the doit() call // // Note: A JavaThread must do the above work. // // 2) doit() is called by the VMThread during a safepoint. It installs // the new class definition(s) which involves: // - retrieving the scratch_class from the instance field in the // VM operation // - house keeping (flushing breakpoints and caches, deoptimizing // dependent compiled code) // - replacing parts in the_class with parts from scratch_class // - adding weak reference(s) to track the obsolete but interesting // parts of the_class // - adjusting constant pool caches and vtables in other classes // that refer to methods in the_class. These adjustments use the // ClassLoaderDataGraph::classes_do() facility which only allows // a helper method to be specified. The interesting parameters // that we would like to pass to the helper method are saved in // static global fields in the VM operation. // - telling the SystemDictionary to notice our changes // // Note: the above work must be done by the VMThread to be safe. // // 3) doit_epilogue() is called by the JavaThread after the VM op // is finished and the safepoint is done. It simply cleans up // memory allocated in doit_prologue() and used in doit(). // // // Constant Pool Details: // // When the_class is redefined, we cannot just replace the constant // pool in the_class with the constant pool from scratch_class because // that could confuse obsolete methods that may still be running. // Instead, the constant pool from the_class, old_cp, is merged with // the constant pool from scratch_class, scratch_cp. The resulting // constant pool, merge_cp, replaces old_cp in the_class. // // The key part of any merging algorithm is the entry comparison // function so we have to know the types of entries in a constant pool // in order to merge two of them together. Constant pools can contain // up to 12 different kinds of entries; the JVM_CONSTANT_Unicode entry // is not presently used so we only have to worry about the other 11 // entry types. For the purposes of constant pool merging, it is // helpful to know that the 11 entry types fall into 3 different // subtypes: "direct", "indirect" and "double-indirect". // // Direct CP entries contain data and do not contain references to // other CP entries. The following are direct CP entries: // JVM_CONSTANT_{Double,Float,Integer,Long,Utf8} // // Indirect CP entries contain 1 or 2 references to a direct CP entry // and no other data. The following are indirect CP entries: // JVM_CONSTANT_{Class,NameAndType,String} // // Double-indirect CP entries contain two references to indirect CP // entries and no other data. The following are double-indirect CP // entries: // JVM_CONSTANT_{Fieldref,InterfaceMethodref,Methodref} // // When comparing entries between two constant pools, the entry types // are compared first and if they match, then further comparisons are // made depending on the entry subtype. Comparing direct CP entries is // simply a matter of comparing the data associated with each entry. // Comparing both indirect and double-indirect CP entries requires // recursion. // // Fortunately, the recursive combinations are limited because indirect // CP entries can only refer to direct CP entries and double-indirect // CP entries can only refer to indirect CP entries. The following is // an example illustration of the deepest set of indirections needed to // access the data associated with a JVM_CONSTANT_Fieldref entry: // // JVM_CONSTANT_Fieldref { // class_index => JVM_CONSTANT_Class { // name_index => JVM_CONSTANT_Utf8 { // <data-1> // } // } // name_and_type_index => JVM_CONSTANT_NameAndType { // name_index => JVM_CONSTANT_Utf8 { // <data-2> // } // descriptor_index => JVM_CONSTANT_Utf8 { // <data-3> // } // } // } // // The above illustration is not a data structure definition for any // computer language. The curly braces ('{' and '}') are meant to // delimit the context of the "fields" in the CP entry types shown. // Each indirection from the JVM_CONSTANT_Fieldref entry is shown via // "=>", e.g., the class_index is used to indirectly reference a // JVM_CONSTANT_Class entry where the name_index is used to indirectly // reference a JVM_CONSTANT_Utf8 entry which contains the interesting // <data-1>. In order to understand a JVM_CONSTANT_Fieldref entry, we // have to do a total of 5 indirections just to get to the CP entries // that contain the interesting pieces of data and then we have to // fetch the three pieces of data. This means we have to do a total of // (5 + 3) * 2 == 16 dereferences to compare two JVM_CONSTANT_Fieldref // entries. // // Here is the indirection, data and dereference count for each entry // type: // // JVM_CONSTANT_Class 1 indir, 1 data, 2 derefs // JVM_CONSTANT_Double 0 indir, 1 data, 1 deref // JVM_CONSTANT_Fieldref 2 indir, 3 data, 8 derefs // JVM_CONSTANT_Float 0 indir, 1 data, 1 deref // JVM_CONSTANT_Integer 0 indir, 1 data, 1 deref // JVM_CONSTANT_InterfaceMethodref 2 indir, 3 data, 8 derefs // JVM_CONSTANT_Long 0 indir, 1 data, 1 deref // JVM_CONSTANT_Methodref 2 indir, 3 data, 8 derefs // JVM_CONSTANT_NameAndType 1 indir, 2 data, 4 derefs // JVM_CONSTANT_String 1 indir, 1 data, 2 derefs // JVM_CONSTANT_Utf8 0 indir, 1 data, 1 deref // // So different subtypes of CP entries require different amounts of // work for a proper comparison. // // Now that we've talked about the different entry types and how to // compare them we need to get back to merging. This is not a merge in // the "sort -u" sense or even in the "sort" sense. When we merge two // constant pools, we copy all the entries from old_cp to merge_cp, // preserving entry order. Next we append all the unique entries from // scratch_cp to merge_cp and we track the index changes from the // location in scratch_cp to the possibly new location in merge_cp. // When we are done, any obsolete code that is still running that // uses old_cp should not be able to observe any difference if it // were to use merge_cp. As for the new code in scratch_class, it is // modified to use the appropriate index values in merge_cp before it // is used to replace the code in the_class. // // There is one small complication in copying the entries from old_cp // to merge_cp. Two of the CP entry types are special in that they are // lazily resolved. Before explaining the copying complication, we need // to digress into CP entry resolution. // // JVM_CONSTANT_Class entries are present in the class file, but are not // stored in memory as such until they are resolved. The entries are not // resolved unless they are used because resolution is expensive. During class // file parsing the entries are initially stored in memory as // JVM_CONSTANT_ClassIndex and JVM_CONSTANT_StringIndex entries. These special // CP entry types indicate that the JVM_CONSTANT_Class and JVM_CONSTANT_String // entries have been parsed, but the index values in the entries have not been // validated. After the entire constant pool has been parsed, the index // values can be validated and then the entries are converted into // JVM_CONSTANT_UnresolvedClass and JVM_CONSTANT_String // entries. During this conversion process, the UTF8 values that are // indirectly referenced by the JVM_CONSTANT_ClassIndex and // JVM_CONSTANT_StringIndex entries are changed into Symbol*s and the // entries are modified to refer to the Symbol*s. This optimization // eliminates one level of indirection for those two CP entry types and // gets the entries ready for verification. Verification expects to // find JVM_CONSTANT_UnresolvedClass but not JVM_CONSTANT_Class entries. // // Now we can get back to the copying complication. When we copy // entries from old_cp to merge_cp, we have to revert any // JVM_CONSTANT_Class entries to JVM_CONSTANT_UnresolvedClass entries // or verification will fail. // // It is important to explicitly state that the merging algorithm // effectively unresolves JVM_CONSTANT_Class entries that were in the // old_cp when they are changed into JVM_CONSTANT_UnresolvedClass // entries in the merge_cp. This is done both to make verification // happy and to avoid adding more brittleness between RedefineClasses // and the constant pool cache. By allowing the constant pool cache // implementation to (re)resolve JVM_CONSTANT_UnresolvedClass entries // into JVM_CONSTANT_Class entries, we avoid having to embed knowledge // about those algorithms in RedefineClasses. // // Appending unique entries from scratch_cp to merge_cp is straight // forward for direct CP entries and most indirect CP entries. For the // indirect CP entry type JVM_CONSTANT_NameAndType and for the double- // indirect CP entry types, the presence of more than one piece of // interesting data makes appending the entries more complicated. // // For the JVM_CONSTANT_{Double,Float,Integer,Long,Utf8} entry types, // the entry is simply copied from scratch_cp to the end of merge_cp. // If the index in scratch_cp is different than the destination index // in merge_cp, then the change in index value is tracked. // // Note: the above discussion for the direct CP entries also applies // to the JVM_CONSTANT_UnresolvedClass entry types. // // For the JVM_CONSTANT_Class entry types, since there is only // one data element at the end of the recursion, we know that we have // either one or two unique entries. If the JVM_CONSTANT_Utf8 entry is // unique then it is appended to merge_cp before the current entry. // If the JVM_CONSTANT_Utf8 entry is not unique, then the current entry // is updated to refer to the duplicate entry in merge_cp before it is // appended to merge_cp. Again, any changes in index values are tracked // as needed. // // Note: the above discussion for JVM_CONSTANT_Class entry // types is theoretical. Since those entry types have already been // optimized into JVM_CONSTANT_UnresolvedClass entry types, // they are handled as direct CP entries. // // For the JVM_CONSTANT_NameAndType entry type, since there are two // data elements at the end of the recursions, we know that we have // between one and three unique entries. Any unique JVM_CONSTANT_Utf8 // entries are appended to merge_cp before the current entry. For any // JVM_CONSTANT_Utf8 entries that are not unique, the current entry is // updated to refer to the duplicate entry in merge_cp before it is // appended to merge_cp. Again, any changes in index values are tracked // as needed. // // For the JVM_CONSTANT_{Fieldref,InterfaceMethodref,Methodref} entry // types, since there are two indirect CP entries and three data // elements at the end of the recursions, we know that we have between // one and six unique entries. See the JVM_CONSTANT_Fieldref diagram // above for an example of all six entries. The uniqueness algorithm // for the JVM_CONSTANT_Class and JVM_CONSTANT_NameAndType entries is // covered above. Any unique entries are appended to merge_cp before // the current entry. For any entries that are not unique, the current // entry is updated to refer to the duplicate entry in merge_cp before // it is appended to merge_cp. Again, any changes in index values are // tracked as needed. // // // Other Details: // // Details for other parts of RedefineClasses need to be written. // This is a placeholder section. // // // Open Issues (in no particular order): // // - How do we serialize the RedefineClasses() API without deadlocking? // // - SystemDictionary::parse_stream() was called with a NULL protection // domain since the initial version. This has been changed to pass // the_class->protection_domain(). This change has been tested with // all NSK tests and nothing broke, but what will adding it now break // in ways that we don't test? // // - GenerateOopMap::rewrite_load_or_store() has a comment in its // (indirect) use of the Relocator class that the max instruction // size is 4 bytes. goto_w and jsr_w are 5 bytes and wide/iinc is // 6 bytes. Perhaps Relocator only needs a 4 byte buffer to do // what it does to the bytecodes. More investigation is needed. // // - How do we know if redefine_single_class() and the guts of // InstanceKlass are out of sync? I don't think this can be // automated, but we should probably order the work in // redefine_single_class() to match the order of field // definitions in InstanceKlass. We also need to add some // comments about keeping things in sync. // // - set_new_constant_pool() is huge and we should consider refactoring // it into smaller chunks of work. // // - The exception table update code in set_new_constant_pool() defines // const values that are also defined in a local context elsewhere. // The same literal values are also used in elsewhere. We need to // coordinate a cleanup of these constants with Runtime. // struct JvmtiCachedClassFileData { jint length; unsigned char data[1]; }; class VM_RedefineClasses: public VM_Operation { private: // These static fields are needed by ClassLoaderDataGraph::classes_do() // facility and the AdjustCpoolCacheAndVtable helper: static Array<Method*>* _old_methods; static Array<Method*>* _new_methods; static Method** _matching_old_methods; static Method** _matching_new_methods; static Method** _deleted_methods; static Method** _added_methods; static int _matching_methods_length; static int _deleted_methods_length; static int _added_methods_length; static Klass* _the_class_oop; // The instance fields are used to pass information from // doit_prologue() to doit() and doit_epilogue(). jint _class_count; const jvmtiClassDefinition *_class_defs; // ptr to _class_count defs // This operation is used by both RedefineClasses and // RetransformClasses. Indicate which. JvmtiClassLoadKind _class_load_kind; // _index_map_count is just an optimization for knowing if // _index_map_p contains any entries. int _index_map_count; intArray * _index_map_p; // _operands_index_map_count is just an optimization for knowing if // _operands_index_map_p contains any entries. int _operands_cur_length; int _operands_index_map_count; intArray * _operands_index_map_p; // ptr to _class_count scratch_classes Klass** _scratch_classes; jvmtiError _res; // Performance measurement support. These timers do not cover all // the work done for JVM/TI RedefineClasses() but they do cover // the heavy lifting. elapsedTimer _timer_rsc_phase1; elapsedTimer _timer_rsc_phase2; elapsedTimer _timer_vm_op_prologue; // These routines are roughly in call order unless otherwise noted. // Load the caller's new class definition(s) into _scratch_classes. // Constant pool merging work is done here as needed. Also calls // compare_and_normalize_class_versions() to verify the class // definition(s). jvmtiError load_new_class_versions(TRAPS); // Verify that the caller provided class definition(s) that meet // the restrictions of RedefineClasses. Normalize the order of // overloaded methods as needed. jvmtiError compare_and_normalize_class_versions( instanceKlassHandle the_class, instanceKlassHandle scratch_class); // Figure out which new methods match old methods in name and signature, // which methods have been added, and which are no longer present void compute_added_deleted_matching_methods(); // Change jmethodIDs to point to the new methods void update_jmethod_ids(); // In addition to marking methods as obsolete, this routine // records which methods are EMCP (Equivalent Module Constant // Pool) in the emcp_methods BitMap and returns the number of // EMCP methods via emcp_method_count_p. This information is // used when information about the previous version of the_class // is squirreled away. void check_methods_and_mark_as_obsolete(BitMap *emcp_methods, int * emcp_method_count_p); void transfer_old_native_function_registrations(instanceKlassHandle the_class); // Install the redefinition of a class void redefine_single_class(jclass the_jclass, Klass* scratch_class_oop, TRAPS); void swap_annotations(instanceKlassHandle new_class, instanceKlassHandle scratch_class); // Increment the classRedefinedCount field in the specific InstanceKlass // and in all direct and indirect subclasses. void increment_class_counter(InstanceKlass *ik, TRAPS); // Support for constant pool merging (these routines are in alpha order): void append_entry(constantPoolHandle scratch_cp, int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS); void append_operand(constantPoolHandle scratch_cp, int scratch_bootstrap_spec_index, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS); void finalize_operands_merge(constantPoolHandle merge_cp, TRAPS); int find_or_append_indirect_entry(constantPoolHandle scratch_cp, int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS); int find_or_append_operand(constantPoolHandle scratch_cp, int scratch_bootstrap_spec_index, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS); int find_new_index(int old_index); int find_new_operand_index(int old_bootstrap_spec_index); bool is_unresolved_class_mismatch(constantPoolHandle cp1, int index1, constantPoolHandle cp2, int index2); void map_index(constantPoolHandle scratch_cp, int old_index, int new_index); void map_operand_index(int old_bootstrap_spec_index, int new_bootstrap_spec_index); bool merge_constant_pools(constantPoolHandle old_cp, constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS); jvmtiError merge_cp_and_rewrite(instanceKlassHandle the_class, instanceKlassHandle scratch_class, TRAPS); u2 rewrite_cp_ref_in_annotation_data( AnnotationArray* annotations_typeArray, int &byte_i_ref, const char * trace_mesg, TRAPS); bool rewrite_cp_refs(instanceKlassHandle scratch_class, TRAPS); bool rewrite_cp_refs_in_annotation_struct( AnnotationArray* class_annotations, int &byte_i_ref, TRAPS); bool rewrite_cp_refs_in_annotations_typeArray( AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS); bool rewrite_cp_refs_in_class_annotations( instanceKlassHandle scratch_class, TRAPS); bool rewrite_cp_refs_in_element_value( AnnotationArray* class_annotations, int &byte_i_ref, TRAPS); bool rewrite_cp_refs_in_fields_annotations( instanceKlassHandle scratch_class, TRAPS); void rewrite_cp_refs_in_method(methodHandle method, methodHandle * new_method_p, TRAPS); bool rewrite_cp_refs_in_methods(instanceKlassHandle scratch_class, TRAPS); bool rewrite_cp_refs_in_methods_annotations( instanceKlassHandle scratch_class, TRAPS); bool rewrite_cp_refs_in_methods_default_annotations( instanceKlassHandle scratch_class, TRAPS); bool rewrite_cp_refs_in_methods_parameter_annotations( instanceKlassHandle scratch_class, TRAPS); void rewrite_cp_refs_in_stack_map_table(methodHandle method, TRAPS); void rewrite_cp_refs_in_verification_type_info( address& stackmap_addr_ref, address stackmap_end, u2 frame_i, u1 frame_size, TRAPS); void set_new_constant_pool(ClassLoaderData* loader_data, instanceKlassHandle scratch_class, constantPoolHandle scratch_cp, int scratch_cp_length, TRAPS); void flush_dependent_code(instanceKlassHandle k_h, TRAPS); static void dump_methods(); // Check that there are no old or obsolete methods class CheckClass : public KlassClosure { Thread* _thread; public: CheckClass(Thread* t) : _thread(t) {} void do_klass(Klass* k); }; // Unevolving classes may point to methods of the_class directly // from their constant pool caches, itables, and/or vtables. We // use the ClassLoaderDataGraph::classes_do() facility and this helper // to fix up these pointers. class AdjustCpoolCacheAndVtable : public KlassClosure { Thread* _thread; public: AdjustCpoolCacheAndVtable(Thread* t) : _thread(t) {} void do_klass(Klass* k); }; public: VM_RedefineClasses(jint class_count, const jvmtiClassDefinition *class_defs, JvmtiClassLoadKind class_load_kind); VMOp_Type type() const { return VMOp_RedefineClasses; } bool doit_prologue(); void doit(); void doit_epilogue(); bool allow_nested_vm_operations() const { return true; } jvmtiError check_error() { return _res; } // Modifiable test must be shared between IsModifiableClass query // and redefine implementation static bool is_modifiable_class(oop klass_mirror); static jint get_cached_class_file_len(JvmtiCachedClassFileData *cache) { return cache == NULL ? 0 : cache->length; } static unsigned char * get_cached_class_file_bytes(JvmtiCachedClassFileData *cache) { return cache == NULL ? NULL : cache->data; } }; #endif // SHARE_VM_PRIMS_JVMTIREDEFINECLASSES_HPP