Mercurial > hg > graal-compiler
view src/share/vm/classfile/symbolTable.cpp @ 13390:d61a1a166f44
8028347: Rewriter::scan_method asserts with array oob in RT_Baseline
Summary: Fix reversing rewriting for invokespecial
Reviewed-by: jrose, hseigel
author | coleenp |
---|---|
date | Fri, 15 Nov 2013 17:20:22 -0500 |
parents | a5ac0873476c |
children | 893ce66f7473 |
line wrap: on
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/* * Copyright (c) 1997, 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. * */ #include "precompiled.hpp" #include "classfile/altHashing.hpp" #include "classfile/javaClasses.hpp" #include "classfile/symbolTable.hpp" #include "classfile/systemDictionary.hpp" #include "gc_interface/collectedHeap.inline.hpp" #include "memory/allocation.inline.hpp" #include "memory/filemap.hpp" #include "memory/gcLocker.inline.hpp" #include "oops/oop.inline.hpp" #include "oops/oop.inline2.hpp" #include "runtime/mutexLocker.hpp" #include "utilities/hashtable.inline.hpp" // -------------------------------------------------------------------------- SymbolTable* SymbolTable::_the_table = NULL; // Static arena for symbols that are not deallocated Arena* SymbolTable::_arena = NULL; bool SymbolTable::_needs_rehashing = false; Symbol* SymbolTable::allocate_symbol(const u1* name, int len, bool c_heap, TRAPS) { assert (len <= Symbol::max_length(), "should be checked by caller"); Symbol* sym; if (DumpSharedSpaces) { // Allocate all symbols to CLD shared metaspace sym = new (len, ClassLoaderData::the_null_class_loader_data(), THREAD) Symbol(name, len, -1); } else if (c_heap) { // refcount starts as 1 sym = new (len, THREAD) Symbol(name, len, 1); assert(sym != NULL, "new should call vm_exit_out_of_memory if C_HEAP is exhausted"); } else { // Allocate to global arena sym = new (len, arena(), THREAD) Symbol(name, len, -1); } return sym; } void SymbolTable::initialize_symbols(int arena_alloc_size) { // Initialize the arena for global symbols, size passed in depends on CDS. if (arena_alloc_size == 0) { _arena = new (mtSymbol) Arena(); } else { _arena = new (mtSymbol) Arena(arena_alloc_size); } } // Call function for all symbols in the symbol table. void SymbolTable::symbols_do(SymbolClosure *cl) { const int n = the_table()->table_size(); for (int i = 0; i < n; i++) { for (HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i); p != NULL; p = p->next()) { cl->do_symbol(p->literal_addr()); } } } int SymbolTable::symbols_removed = 0; int SymbolTable::symbols_counted = 0; // Remove unreferenced symbols from the symbol table // This is done late during GC. void SymbolTable::unlink() { int removed = 0; int total = 0; size_t memory_total = 0; for (int i = 0; i < the_table()->table_size(); ++i) { HashtableEntry<Symbol*, mtSymbol>** p = the_table()->bucket_addr(i); HashtableEntry<Symbol*, mtSymbol>* entry = the_table()->bucket(i); while (entry != NULL) { // Shared entries are normally at the end of the bucket and if we run into // a shared entry, then there is nothing more to remove. However, if we // have rehashed the table, then the shared entries are no longer at the // end of the bucket. if (entry->is_shared() && !use_alternate_hashcode()) { break; } Symbol* s = entry->literal(); memory_total += s->size(); total++; assert(s != NULL, "just checking"); // If reference count is zero, remove. if (s->refcount() == 0) { assert(!entry->is_shared(), "shared entries should be kept live"); delete s; removed++; *p = entry->next(); the_table()->free_entry(entry); } else { p = entry->next_addr(); } // get next entry entry = (HashtableEntry<Symbol*, mtSymbol>*)HashtableEntry<Symbol*, mtSymbol>::make_ptr(*p); } } symbols_removed += removed; symbols_counted += total; // Exclude printing for normal PrintGCDetails because people parse // this output. if (PrintGCDetails && Verbose && WizardMode) { gclog_or_tty->print(" [Symbols=%d size=" SIZE_FORMAT "K] ", total, (memory_total*HeapWordSize)/1024); } } // Create a new table and using alternate hash code, populate the new table // with the existing strings. Set flag to use the alternate hash code afterwards. void SymbolTable::rehash_table() { assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); // This should never happen with -Xshare:dump but it might in testing mode. if (DumpSharedSpaces) return; // Create a new symbol table SymbolTable* new_table = new SymbolTable(); the_table()->move_to(new_table); // Delete the table and buckets (entries are reused in new table). delete _the_table; // Don't check if we need rehashing until the table gets unbalanced again. // Then rehash with a new global seed. _needs_rehashing = false; _the_table = new_table; } // Lookup a symbol in a bucket. Symbol* SymbolTable::lookup(int index, const char* name, int len, unsigned int hash) { int count = 0; for (HashtableEntry<Symbol*, mtSymbol>* e = bucket(index); e != NULL; e = e->next()) { count++; // count all entries in this bucket, not just ones with same hash if (e->hash() == hash) { Symbol* sym = e->literal(); if (sym->equals(name, len)) { // something is referencing this symbol now. sym->increment_refcount(); return sym; } } } // If the bucket size is too deep check if this hash code is insufficient. if (count >= BasicHashtable<mtSymbol>::rehash_count && !needs_rehashing()) { _needs_rehashing = check_rehash_table(count); } return NULL; } // Pick hashing algorithm. unsigned int SymbolTable::hash_symbol(const char* s, int len) { return use_alternate_hashcode() ? AltHashing::murmur3_32(seed(), (const jbyte*)s, len) : java_lang_String::hash_code(s, len); } // We take care not to be blocking while holding the // SymbolTable_lock. Otherwise, the system might deadlock, since the // symboltable is used during compilation (VM_thread) The lock free // synchronization is simplified by the fact that we do not delete // entries in the symbol table during normal execution (only during // safepoints). Symbol* SymbolTable::lookup(const char* name, int len, TRAPS) { unsigned int hashValue = hash_symbol(name, len); int index = the_table()->hash_to_index(hashValue); Symbol* s = the_table()->lookup(index, name, len, hashValue); // Found if (s != NULL) return s; // Grab SymbolTable_lock first. MutexLocker ml(SymbolTable_lock, THREAD); // Otherwise, add to symbol to table return the_table()->basic_add(index, (u1*)name, len, hashValue, true, CHECK_NULL); } Symbol* SymbolTable::lookup(const Symbol* sym, int begin, int end, TRAPS) { char* buffer; int index, len; unsigned int hashValue; char* name; { debug_only(No_Safepoint_Verifier nsv;) name = (char*)sym->base() + begin; len = end - begin; hashValue = hash_symbol(name, len); index = the_table()->hash_to_index(hashValue); Symbol* s = the_table()->lookup(index, name, len, hashValue); // Found if (s != NULL) return s; } // Otherwise, add to symbol to table. Copy to a C string first. char stack_buf[128]; ResourceMark rm(THREAD); if (len <= 128) { buffer = stack_buf; } else { buffer = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len); } for (int i=0; i<len; i++) { buffer[i] = name[i]; } // Make sure there is no safepoint in the code above since name can't move. // We can't include the code in No_Safepoint_Verifier because of the // ResourceMark. // Grab SymbolTable_lock first. MutexLocker ml(SymbolTable_lock, THREAD); return the_table()->basic_add(index, (u1*)buffer, len, hashValue, true, CHECK_NULL); } Symbol* SymbolTable::lookup_only(const char* name, int len, unsigned int& hash) { hash = hash_symbol(name, len); int index = the_table()->hash_to_index(hash); Symbol* s = the_table()->lookup(index, name, len, hash); return s; } // Look up the address of the literal in the SymbolTable for this Symbol* // Do not create any new symbols // Do not increment the reference count to keep this alive Symbol** SymbolTable::lookup_symbol_addr(Symbol* sym){ unsigned int hash = hash_symbol((char*)sym->bytes(), sym->utf8_length()); int index = the_table()->hash_to_index(hash); for (HashtableEntry<Symbol*, mtSymbol>* e = the_table()->bucket(index); e != NULL; e = e->next()) { if (e->hash() == hash) { Symbol* literal_sym = e->literal(); if (sym == literal_sym) { return e->literal_addr(); } } } return NULL; } // Suggestion: Push unicode-based lookup all the way into the hashing // and probing logic, so there is no need for convert_to_utf8 until // an actual new Symbol* is created. Symbol* SymbolTable::lookup_unicode(const jchar* name, int utf16_length, TRAPS) { int utf8_length = UNICODE::utf8_length((jchar*) name, utf16_length); char stack_buf[128]; if (utf8_length < (int) sizeof(stack_buf)) { char* chars = stack_buf; UNICODE::convert_to_utf8(name, utf16_length, chars); return lookup(chars, utf8_length, THREAD); } else { ResourceMark rm(THREAD); char* chars = NEW_RESOURCE_ARRAY(char, utf8_length + 1);; UNICODE::convert_to_utf8(name, utf16_length, chars); return lookup(chars, utf8_length, THREAD); } } Symbol* SymbolTable::lookup_only_unicode(const jchar* name, int utf16_length, unsigned int& hash) { int utf8_length = UNICODE::utf8_length((jchar*) name, utf16_length); char stack_buf[128]; if (utf8_length < (int) sizeof(stack_buf)) { char* chars = stack_buf; UNICODE::convert_to_utf8(name, utf16_length, chars); return lookup_only(chars, utf8_length, hash); } else { ResourceMark rm; char* chars = NEW_RESOURCE_ARRAY(char, utf8_length + 1);; UNICODE::convert_to_utf8(name, utf16_length, chars); return lookup_only(chars, utf8_length, hash); } } void SymbolTable::add(ClassLoaderData* loader_data, constantPoolHandle cp, int names_count, const char** names, int* lengths, int* cp_indices, unsigned int* hashValues, TRAPS) { // Grab SymbolTable_lock first. MutexLocker ml(SymbolTable_lock, THREAD); SymbolTable* table = the_table(); bool added = table->basic_add(loader_data, cp, names_count, names, lengths, cp_indices, hashValues, CHECK); if (!added) { // do it the hard way for (int i=0; i<names_count; i++) { int index = table->hash_to_index(hashValues[i]); bool c_heap = !loader_data->is_the_null_class_loader_data(); Symbol* sym = table->basic_add(index, (u1*)names[i], lengths[i], hashValues[i], c_heap, CHECK); cp->symbol_at_put(cp_indices[i], sym); } } } Symbol* SymbolTable::new_permanent_symbol(const char* name, TRAPS) { unsigned int hash; Symbol* result = SymbolTable::lookup_only((char*)name, (int)strlen(name), hash); if (result != NULL) { return result; } // Grab SymbolTable_lock first. MutexLocker ml(SymbolTable_lock, THREAD); SymbolTable* table = the_table(); int index = table->hash_to_index(hash); return table->basic_add(index, (u1*)name, (int)strlen(name), hash, false, THREAD); } Symbol* SymbolTable::basic_add(int index_arg, u1 *name, int len, unsigned int hashValue_arg, bool c_heap, TRAPS) { assert(!Universe::heap()->is_in_reserved(name), "proposed name of symbol must be stable"); // Don't allow symbols to be created which cannot fit in a Symbol*. if (len > Symbol::max_length()) { THROW_MSG_0(vmSymbols::java_lang_InternalError(), "name is too long to represent"); } // Cannot hit a safepoint in this function because the "this" pointer can move. No_Safepoint_Verifier nsv; // Check if the symbol table has been rehashed, if so, need to recalculate // the hash value and index. unsigned int hashValue; int index; if (use_alternate_hashcode()) { hashValue = hash_symbol((const char*)name, len); index = hash_to_index(hashValue); } else { hashValue = hashValue_arg; index = index_arg; } // Since look-up was done lock-free, we need to check if another // thread beat us in the race to insert the symbol. Symbol* test = lookup(index, (char*)name, len, hashValue); if (test != NULL) { // A race occurred and another thread introduced the symbol. assert(test->refcount() != 0, "lookup should have incremented the count"); return test; } // Create a new symbol. Symbol* sym = allocate_symbol(name, len, c_heap, CHECK_NULL); assert(sym->equals((char*)name, len), "symbol must be properly initialized"); HashtableEntry<Symbol*, mtSymbol>* entry = new_entry(hashValue, sym); add_entry(index, entry); return sym; } // This version of basic_add adds symbols in batch from the constant pool // parsing. bool SymbolTable::basic_add(ClassLoaderData* loader_data, constantPoolHandle cp, int names_count, const char** names, int* lengths, int* cp_indices, unsigned int* hashValues, TRAPS) { // Check symbol names are not too long. If any are too long, don't add any. for (int i = 0; i< names_count; i++) { if (lengths[i] > Symbol::max_length()) { THROW_MSG_0(vmSymbols::java_lang_InternalError(), "name is too long to represent"); } } // Cannot hit a safepoint in this function because the "this" pointer can move. No_Safepoint_Verifier nsv; for (int i=0; i<names_count; i++) { // Check if the symbol table has been rehashed, if so, need to recalculate // the hash value. unsigned int hashValue; if (use_alternate_hashcode()) { hashValue = hash_symbol(names[i], lengths[i]); } else { hashValue = hashValues[i]; } // Since look-up was done lock-free, we need to check if another // thread beat us in the race to insert the symbol. int index = hash_to_index(hashValue); Symbol* test = lookup(index, names[i], lengths[i], hashValue); if (test != NULL) { // A race occurred and another thread introduced the symbol, this one // will be dropped and collected. Use test instead. cp->symbol_at_put(cp_indices[i], test); assert(test->refcount() != 0, "lookup should have incremented the count"); } else { // Create a new symbol. The null class loader is never unloaded so these // are allocated specially in a permanent arena. bool c_heap = !loader_data->is_the_null_class_loader_data(); Symbol* sym = allocate_symbol((const u1*)names[i], lengths[i], c_heap, CHECK_(false)); assert(sym->equals(names[i], lengths[i]), "symbol must be properly initialized"); // why wouldn't it be??? HashtableEntry<Symbol*, mtSymbol>* entry = new_entry(hashValue, sym); add_entry(index, entry); cp->symbol_at_put(cp_indices[i], sym); } } return true; } void SymbolTable::verify() { for (int i = 0; i < the_table()->table_size(); ++i) { HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i); for ( ; p != NULL; p = p->next()) { Symbol* s = (Symbol*)(p->literal()); guarantee(s != NULL, "symbol is NULL"); unsigned int h = hash_symbol((char*)s->bytes(), s->utf8_length()); guarantee(p->hash() == h, "broken hash in symbol table entry"); guarantee(the_table()->hash_to_index(h) == i, "wrong index in symbol table"); } } } void SymbolTable::dump(outputStream* st) { the_table()->dump_table(st, "SymbolTable"); } //--------------------------------------------------------------------------- // Non-product code #ifndef PRODUCT void SymbolTable::print_histogram() { MutexLocker ml(SymbolTable_lock); const int results_length = 100; int results[results_length]; int i,j; // initialize results to zero for (j = 0; j < results_length; j++) { results[j] = 0; } int total = 0; int max_symbols = 0; int out_of_range = 0; int memory_total = 0; int count = 0; for (i = 0; i < the_table()->table_size(); i++) { HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i); for ( ; p != NULL; p = p->next()) { memory_total += p->literal()->size(); count++; int counter = p->literal()->utf8_length(); total += counter; if (counter < results_length) { results[counter]++; } else { out_of_range++; } max_symbols = MAX2(max_symbols, counter); } } tty->print_cr("Symbol Table:"); tty->print_cr("Total number of symbols %5d", count); tty->print_cr("Total size in memory %5dK", (memory_total*HeapWordSize)/1024); tty->print_cr("Total counted %5d", symbols_counted); tty->print_cr("Total removed %5d", symbols_removed); if (symbols_counted > 0) { tty->print_cr("Percent removed %3.2f", ((float)symbols_removed/(float)symbols_counted)* 100); } tty->print_cr("Reference counts %5d", Symbol::_total_count); tty->print_cr("Symbol arena size %5d used %5d", arena()->size_in_bytes(), arena()->used()); tty->print_cr("Histogram of symbol length:"); tty->print_cr("%8s %5d", "Total ", total); tty->print_cr("%8s %5d", "Maximum", max_symbols); tty->print_cr("%8s %3.2f", "Average", ((float) total / (float) the_table()->table_size())); tty->print_cr("%s", "Histogram:"); tty->print_cr(" %s %29s", "Length", "Number chains that length"); for (i = 0; i < results_length; i++) { if (results[i] > 0) { tty->print_cr("%6d %10d", i, results[i]); } } if (Verbose) { int line_length = 70; tty->print_cr("%s %30s", " Length", "Number chains that length"); for (i = 0; i < results_length; i++) { if (results[i] > 0) { tty->print("%4d", i); for (j = 0; (j < results[i]) && (j < line_length); j++) { tty->print("%1s", "*"); } if (j == line_length) { tty->print("%1s", "+"); } tty->cr(); } } } tty->print_cr(" %s %d: %d\n", "Number chains longer than", results_length, out_of_range); } void SymbolTable::print() { for (int i = 0; i < the_table()->table_size(); ++i) { HashtableEntry<Symbol*, mtSymbol>** p = the_table()->bucket_addr(i); HashtableEntry<Symbol*, mtSymbol>* entry = the_table()->bucket(i); if (entry != NULL) { while (entry != NULL) { tty->print(PTR_FORMAT " ", entry->literal()); entry->literal()->print(); tty->print(" %d", entry->literal()->refcount()); p = entry->next_addr(); entry = (HashtableEntry<Symbol*, mtSymbol>*)HashtableEntry<Symbol*, mtSymbol>::make_ptr(*p); } tty->cr(); } } } #endif // PRODUCT // -------------------------------------------------------------------------- #ifdef ASSERT class StableMemoryChecker : public StackObj { enum { _bufsize = wordSize*4 }; address _region; jint _size; u1 _save_buf[_bufsize]; int sample(u1* save_buf) { if (_size <= _bufsize) { memcpy(save_buf, _region, _size); return _size; } else { // copy head and tail memcpy(&save_buf[0], _region, _bufsize/2); memcpy(&save_buf[_bufsize/2], _region + _size - _bufsize/2, _bufsize/2); return (_bufsize/2)*2; } } public: StableMemoryChecker(const void* region, jint size) { _region = (address) region; _size = size; sample(_save_buf); } bool verify() { u1 check_buf[sizeof(_save_buf)]; int check_size = sample(check_buf); return (0 == memcmp(_save_buf, check_buf, check_size)); } void set_region(const void* region) { _region = (address) region; } }; #endif // -------------------------------------------------------------------------- StringTable* StringTable::_the_table = NULL; bool StringTable::_needs_rehashing = false; volatile int StringTable::_parallel_claimed_idx = 0; // Pick hashing algorithm unsigned int StringTable::hash_string(const jchar* s, int len) { return use_alternate_hashcode() ? AltHashing::murmur3_32(seed(), s, len) : java_lang_String::hash_code(s, len); } oop StringTable::lookup(int index, jchar* name, int len, unsigned int hash) { int count = 0; for (HashtableEntry<oop, mtSymbol>* l = bucket(index); l != NULL; l = l->next()) { count++; if (l->hash() == hash) { if (java_lang_String::equals(l->literal(), name, len)) { return l->literal(); } } } // If the bucket size is too deep check if this hash code is insufficient. if (count >= BasicHashtable<mtSymbol>::rehash_count && !needs_rehashing()) { _needs_rehashing = check_rehash_table(count); } return NULL; } oop StringTable::basic_add(int index_arg, Handle string, jchar* name, int len, unsigned int hashValue_arg, TRAPS) { assert(java_lang_String::equals(string(), name, len), "string must be properly initialized"); // Cannot hit a safepoint in this function because the "this" pointer can move. No_Safepoint_Verifier nsv; // Check if the symbol table has been rehashed, if so, need to recalculate // the hash value and index before second lookup. unsigned int hashValue; int index; if (use_alternate_hashcode()) { hashValue = hash_string(name, len); index = hash_to_index(hashValue); } else { hashValue = hashValue_arg; index = index_arg; } // Since look-up was done lock-free, we need to check if another // thread beat us in the race to insert the symbol. oop test = lookup(index, name, len, hashValue); // calls lookup(u1*, int) if (test != NULL) { // Entry already added return test; } HashtableEntry<oop, mtSymbol>* entry = new_entry(hashValue, string()); add_entry(index, entry); return string(); } oop StringTable::lookup(Symbol* symbol) { ResourceMark rm; int length; jchar* chars = symbol->as_unicode(length); return lookup(chars, length); } oop StringTable::lookup(jchar* name, int len) { unsigned int hash = hash_string(name, len); int index = the_table()->hash_to_index(hash); return the_table()->lookup(index, name, len, hash); } oop StringTable::intern(Handle string_or_null, jchar* name, int len, TRAPS) { unsigned int hashValue = hash_string(name, len); int index = the_table()->hash_to_index(hashValue); oop found_string = the_table()->lookup(index, name, len, hashValue); // Found if (found_string != NULL) return found_string; debug_only(StableMemoryChecker smc(name, len * sizeof(name[0]))); assert(!Universe::heap()->is_in_reserved(name), "proposed name of symbol must be stable"); Handle string; // try to reuse the string if possible if (!string_or_null.is_null()) { string = string_or_null; } else { string = java_lang_String::create_from_unicode(name, len, CHECK_NULL); } // Grab the StringTable_lock before getting the_table() because it could // change at safepoint. MutexLocker ml(StringTable_lock, THREAD); // Otherwise, add to symbol to table return the_table()->basic_add(index, string, name, len, hashValue, CHECK_NULL); } oop StringTable::intern(Symbol* symbol, TRAPS) { if (symbol == NULL) return NULL; ResourceMark rm(THREAD); int length; jchar* chars = symbol->as_unicode(length); Handle string; oop result = intern(string, chars, length, CHECK_NULL); return result; } oop StringTable::intern(oop string, TRAPS) { if (string == NULL) return NULL; ResourceMark rm(THREAD); int length; Handle h_string (THREAD, string); jchar* chars = java_lang_String::as_unicode_string(string, length, CHECK_NULL); oop result = intern(h_string, chars, length, CHECK_NULL); return result; } oop StringTable::intern(const char* utf8_string, TRAPS) { if (utf8_string == NULL) return NULL; ResourceMark rm(THREAD); int length = UTF8::unicode_length(utf8_string); jchar* chars = NEW_RESOURCE_ARRAY(jchar, length); UTF8::convert_to_unicode(utf8_string, chars, length); Handle string; oop result = intern(string, chars, length, CHECK_NULL); return result; } void StringTable::unlink_or_oops_do(BoolObjectClosure* is_alive, OopClosure* f) { // Readers of the table are unlocked, so we should only be removing // entries at a safepoint. assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); for (int i = 0; i < the_table()->table_size(); ++i) { HashtableEntry<oop, mtSymbol>** p = the_table()->bucket_addr(i); HashtableEntry<oop, mtSymbol>* entry = the_table()->bucket(i); while (entry != NULL) { assert(!entry->is_shared(), "CDS not used for the StringTable"); if (is_alive->do_object_b(entry->literal())) { if (f != NULL) { f->do_oop((oop*)entry->literal_addr()); } p = entry->next_addr(); } else { *p = entry->next(); the_table()->free_entry(entry); } entry = *p; } } } void StringTable::buckets_do(OopClosure* f, int start_idx, int end_idx) { const int limit = the_table()->table_size(); assert(0 <= start_idx && start_idx <= limit, err_msg("start_idx (" INT32_FORMAT ") oob?", start_idx)); assert(0 <= end_idx && end_idx <= limit, err_msg("end_idx (" INT32_FORMAT ") oob?", end_idx)); assert(start_idx <= end_idx, err_msg("Ordering: start_idx=" INT32_FORMAT", end_idx=" INT32_FORMAT, start_idx, end_idx)); for (int i = start_idx; i < end_idx; i += 1) { HashtableEntry<oop, mtSymbol>* entry = the_table()->bucket(i); while (entry != NULL) { assert(!entry->is_shared(), "CDS not used for the StringTable"); f->do_oop((oop*)entry->literal_addr()); entry = entry->next(); } } } void StringTable::oops_do(OopClosure* f) { buckets_do(f, 0, the_table()->table_size()); } void StringTable::possibly_parallel_oops_do(OopClosure* f) { const int ClaimChunkSize = 32; const int limit = the_table()->table_size(); for (;;) { // Grab next set of buckets to scan int start_idx = Atomic::add(ClaimChunkSize, &_parallel_claimed_idx) - ClaimChunkSize; if (start_idx >= limit) { // End of table break; } int end_idx = MIN2(limit, start_idx + ClaimChunkSize); buckets_do(f, start_idx, end_idx); } } // This verification is part of Universe::verify() and needs to be quick. // See StringTable::verify_and_compare() below for exhaustive verification. void StringTable::verify() { for (int i = 0; i < the_table()->table_size(); ++i) { HashtableEntry<oop, mtSymbol>* p = the_table()->bucket(i); for ( ; p != NULL; p = p->next()) { oop s = p->literal(); guarantee(s != NULL, "interned string is NULL"); unsigned int h = java_lang_String::hash_string(s); guarantee(p->hash() == h, "broken hash in string table entry"); guarantee(the_table()->hash_to_index(h) == i, "wrong index in string table"); } } } void StringTable::dump(outputStream* st) { the_table()->dump_table(st, "StringTable"); } StringTable::VerifyRetTypes StringTable::compare_entries( int bkt1, int e_cnt1, HashtableEntry<oop, mtSymbol>* e_ptr1, int bkt2, int e_cnt2, HashtableEntry<oop, mtSymbol>* e_ptr2) { // These entries are sanity checked by verify_and_compare_entries() // before this function is called. oop str1 = e_ptr1->literal(); oop str2 = e_ptr2->literal(); if (str1 == str2) { tty->print_cr("ERROR: identical oop values (0x" PTR_FORMAT ") " "in entry @ bucket[%d][%d] and entry @ bucket[%d][%d]", (void *)str1, bkt1, e_cnt1, bkt2, e_cnt2); return _verify_fail_continue; } if (java_lang_String::equals(str1, str2)) { tty->print_cr("ERROR: identical String values in entry @ " "bucket[%d][%d] and entry @ bucket[%d][%d]", bkt1, e_cnt1, bkt2, e_cnt2); return _verify_fail_continue; } return _verify_pass; } StringTable::VerifyRetTypes StringTable::verify_entry(int bkt, int e_cnt, HashtableEntry<oop, mtSymbol>* e_ptr, StringTable::VerifyMesgModes mesg_mode) { VerifyRetTypes ret = _verify_pass; // be optimistic oop str = e_ptr->literal(); if (str == NULL) { if (mesg_mode == _verify_with_mesgs) { tty->print_cr("ERROR: NULL oop value in entry @ bucket[%d][%d]", bkt, e_cnt); } // NULL oop means no more verifications are possible return _verify_fail_done; } if (str->klass() != SystemDictionary::String_klass()) { if (mesg_mode == _verify_with_mesgs) { tty->print_cr("ERROR: oop is not a String in entry @ bucket[%d][%d]", bkt, e_cnt); } // not a String means no more verifications are possible return _verify_fail_done; } unsigned int h = java_lang_String::hash_string(str); if (e_ptr->hash() != h) { if (mesg_mode == _verify_with_mesgs) { tty->print_cr("ERROR: broken hash value in entry @ bucket[%d][%d], " "bkt_hash=%d, str_hash=%d", bkt, e_cnt, e_ptr->hash(), h); } ret = _verify_fail_continue; } if (the_table()->hash_to_index(h) != bkt) { if (mesg_mode == _verify_with_mesgs) { tty->print_cr("ERROR: wrong index value for entry @ bucket[%d][%d], " "str_hash=%d, hash_to_index=%d", bkt, e_cnt, h, the_table()->hash_to_index(h)); } ret = _verify_fail_continue; } return ret; } // See StringTable::verify() above for the quick verification that is // part of Universe::verify(). This verification is exhaustive and // reports on every issue that is found. StringTable::verify() only // reports on the first issue that is found. // // StringTable::verify_entry() checks: // - oop value != NULL (same as verify()) // - oop value is a String // - hash(String) == hash in entry (same as verify()) // - index for hash == index of entry (same as verify()) // // StringTable::compare_entries() checks: // - oops are unique across all entries // - String values are unique across all entries // int StringTable::verify_and_compare_entries() { assert(StringTable_lock->is_locked(), "sanity check"); int fail_cnt = 0; // first, verify all the entries individually: for (int bkt = 0; bkt < the_table()->table_size(); bkt++) { HashtableEntry<oop, mtSymbol>* e_ptr = the_table()->bucket(bkt); for (int e_cnt = 0; e_ptr != NULL; e_ptr = e_ptr->next(), e_cnt++) { VerifyRetTypes ret = verify_entry(bkt, e_cnt, e_ptr, _verify_with_mesgs); if (ret != _verify_pass) { fail_cnt++; } } } // Optimization: if the above check did not find any failures, then // the comparison loop below does not need to call verify_entry() // before calling compare_entries(). If there were failures, then we // have to call verify_entry() to see if the entry can be passed to // compare_entries() safely. When we call verify_entry() in the loop // below, we do so quietly to void duplicate messages and we don't // increment fail_cnt because the failures have already been counted. bool need_entry_verify = (fail_cnt != 0); // second, verify all entries relative to each other: for (int bkt1 = 0; bkt1 < the_table()->table_size(); bkt1++) { HashtableEntry<oop, mtSymbol>* e_ptr1 = the_table()->bucket(bkt1); for (int e_cnt1 = 0; e_ptr1 != NULL; e_ptr1 = e_ptr1->next(), e_cnt1++) { if (need_entry_verify) { VerifyRetTypes ret = verify_entry(bkt1, e_cnt1, e_ptr1, _verify_quietly); if (ret == _verify_fail_done) { // cannot use the current entry to compare against other entries continue; } } for (int bkt2 = bkt1; bkt2 < the_table()->table_size(); bkt2++) { HashtableEntry<oop, mtSymbol>* e_ptr2 = the_table()->bucket(bkt2); int e_cnt2; for (e_cnt2 = 0; e_ptr2 != NULL; e_ptr2 = e_ptr2->next(), e_cnt2++) { if (bkt1 == bkt2 && e_cnt2 <= e_cnt1) { // skip the entries up to and including the one that // we're comparing against continue; } if (need_entry_verify) { VerifyRetTypes ret = verify_entry(bkt2, e_cnt2, e_ptr2, _verify_quietly); if (ret == _verify_fail_done) { // cannot compare against this entry continue; } } // compare two entries, report and count any failures: if (compare_entries(bkt1, e_cnt1, e_ptr1, bkt2, e_cnt2, e_ptr2) != _verify_pass) { fail_cnt++; } } } } } return fail_cnt; } // Create a new table and using alternate hash code, populate the new table // with the existing strings. Set flag to use the alternate hash code afterwards. void StringTable::rehash_table() { assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); // This should never happen with -Xshare:dump but it might in testing mode. if (DumpSharedSpaces) return; StringTable* new_table = new StringTable(); // Rehash the table the_table()->move_to(new_table); // Delete the table and buckets (entries are reused in new table). delete _the_table; // Don't check if we need rehashing until the table gets unbalanced again. // Then rehash with a new global seed. _needs_rehashing = false; _the_table = new_table; }