src/share/vm/classfile/stringTable.cpp

*** 35,44 ****
--- 35,45 ----
  #include "oops/oop.inline2.hpp"
  #include "runtime/atomic.inline.hpp"
  #include "runtime/mutexLocker.hpp"
  #include "utilities/hashtable.inline.hpp"
  #if INCLUDE_ALL_GCS
+ #include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
  #include "gc_implementation/g1/g1StringDedup.hpp"
  #endif
  
  PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  
*** 155,180 ****
    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");
  
--- 156,199 ----
    int length;
    jchar* chars = symbol->as_unicode(length);
    return lookup(chars, length);
  }
  
+ // Tell the GC that this string was looked up in the StringTable.
+ static void ensure_string_alive(oop string) {
+   // A lookup in the StringTable could return an object that was previously
+   // considered dead. The SATB part of G1 needs to get notified about this
+   // potential resurrection, otherwise the marking might not find the object.
+ #if INCLUDE_ALL_GCS
+   if (UseG1GC && string != NULL) {
+     G1SATBCardTableModRefBS::enqueue(string);
+   }
+ #endif
+ }
  
  oop StringTable::lookup(jchar* name, int len) {
    unsigned int hash = hash_string(name, len);
    int index = the_table()->hash_to_index(hash);
!   oop string = the_table()->lookup(index, name, len, hash);
! 
!   ensure_string_alive(string);
! 
!   return string;
  }
  
  
  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) {
!     ensure_string_alive(found_string);
!     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");
  
*** 195,209 ****
    }
  #endif
  
    // 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);
--- 214,234 ----
    }
  #endif
  
    // Grab the StringTable_lock before getting the_table() because it could
    // change at safepoint.
+   oop added_or_found;
+   {
      MutexLocker ml(StringTable_lock, THREAD);
      // Otherwise, add to symbol to table
!     added_or_found = the_table()->basic_add(index, string, name, len,
                                    hashValue, CHECK_NULL);
+   }
+ 
+   ensure_string_alive(added_or_found);
+ 
+   return added_or_found;
  }
  
  oop StringTable::intern(Symbol* symbol, TRAPS) {
    if (symbol == NULL) return NULL;
    ResourceMark rm(THREAD);