diff -r 6f45933aef35 -r 63147986a428 src/share/vm/classfile/symbolTable.cpp --- a/src/share/vm/classfile/symbolTable.cpp Tue Sep 17 20:20:03 2013 +0200 +++ b/src/share/vm/classfile/symbolTable.cpp Wed Sep 18 07:02:10 2013 -0700 @@ -807,6 +807,8 @@ } } +// 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* p = the_table()->bucket(i); @@ -825,6 +827,162 @@ the_table()->dump_table(st, "StringTable"); } +StringTable::VerifyRetTypes StringTable::compare_entries( + int bkt1, int e_cnt1, + HashtableEntry* e_ptr1, + int bkt2, int e_cnt2, + HashtableEntry* 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]", + 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* 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* 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* 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* 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.