OSDN Git Service

2008-08-22 Andrew Haley <aph@redhat.com>
[pf3gnuchains/gcc-fork.git] / libjava / link.cc
index f995531..c07b6e1 100644 (file)
@@ -380,6 +380,19 @@ _Jv_Linker::resolve_method_entry (jclass klass, jclass &found_class,
   return the_method;
 }
 
+_Jv_Mutex_t _Jv_Linker::resolve_mutex;
+
+void
+_Jv_Linker::init (void)
+{
+  _Jv_MutexInit (&_Jv_Linker::resolve_mutex);
+}
+
+// Locking in resolve_pool_entry is somewhat subtle.  Constant
+// resolution is idempotent, so it doesn't matter if two threads
+// resolve the same entry.  However, it is important that we always
+// write the resolved flag and the data together, atomically.  It is
+// also important that we read them atomically.
 _Jv_word
 _Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy)
 {
@@ -387,6 +400,10 @@ _Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy)
 
   if (GC_base (klass) && klass->constants.data
       && ! GC_base (klass->constants.data))
+    // If a class is heap-allocated but the constant pool is not this
+    // is a "new ABI" class, i.e. one where the initial constant pool
+    // is in the read-only data section of an object file.  Copy the
+    // initial constant pool from there to a new heap-allocated pool.
     {
       jsize count = klass->constants.size;
       if (count)
@@ -402,14 +419,18 @@ _Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy)
 
   _Jv_Constants *pool = &klass->constants;
 
-  if ((pool->tags[index] & JV_CONSTANT_ResolvedFlag) != 0)
-    return pool->data[index];
+  jbyte tags;
+  _Jv_word data;
+  tags = read_cpool_entry (&data, pool, index);
 
-  switch (pool->tags[index] & ~JV_CONSTANT_LazyFlag)
+  if ((tags & JV_CONSTANT_ResolvedFlag) != 0)
+    return data;
+
+  switch (tags & ~JV_CONSTANT_LazyFlag)
     {
     case JV_CONSTANT_Class:
       {
-       _Jv_Utf8Const *name = pool->data[index].utf8;
+       _Jv_Utf8Const *name = data.utf8;
 
        jclass found;
        if (name->first() == '[')
@@ -428,8 +449,8 @@ _Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy)
              {
                found = _Jv_NewClass(name, NULL, NULL);
                found->state = JV_STATE_PHANTOM;
-               pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
-               pool->data[index].clazz = found;
+               tags |= JV_CONSTANT_ResolvedFlag;
+               data.clazz = found;
                break;
              }
            else
@@ -447,8 +468,8 @@ _Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy)
            || (_Jv_ClassNameSamePackage (check->name,
                                          klass->name)))
          {
-           pool->data[index].clazz = found;
-           pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
+           data.clazz = found;
+           tags |= JV_CONSTANT_ResolvedFlag;
          }
        else
          {
@@ -464,16 +485,16 @@ _Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy)
     case JV_CONSTANT_String:
       {
        jstring str;
-       str = _Jv_NewStringUtf8Const (pool->data[index].utf8);
-       pool->data[index].o = str;
-       pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
+       str = _Jv_NewStringUtf8Const (data.utf8);
+       data.o = str;
+       tags |= JV_CONSTANT_ResolvedFlag;
       }
       break;
 
     case JV_CONSTANT_Fieldref:
       {
        _Jv_ushort class_index, name_and_type_index;
-       _Jv_loadIndexes (&pool->data[index],
+       _Jv_loadIndexes (&data,
                         class_index,
                         name_and_type_index);
        jclass owner = (resolve_pool_entry (klass, class_index, true)).clazz;
@@ -503,8 +524,8 @@ _Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy)
        // Initialize the field's declaring class, not its qualifying
        // class.
        _Jv_InitClass (found_class);
-       pool->data[index].field = the_field;
-       pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
+       data.field = the_field;
+       tags |= JV_CONSTANT_ResolvedFlag;
       }
       break;
 
@@ -512,7 +533,7 @@ _Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy)
     case JV_CONSTANT_InterfaceMethodref:
       {
        _Jv_ushort class_index, name_and_type_index;
-       _Jv_loadIndexes (&pool->data[index],
+       _Jv_loadIndexes (&data,
                         class_index,
                         name_and_type_index);
 
@@ -521,18 +542,21 @@ _Jv_Linker::resolve_pool_entry (jclass klass, int index, bool lazy)
        the_method = resolve_method_entry (klass, found_class,
                                           class_index, name_and_type_index,
                                           true,
-                                          pool->tags[index] == JV_CONSTANT_InterfaceMethodref);
+                                          tags == JV_CONSTANT_InterfaceMethodref);
       
-       pool->data[index].rmethod
+       data.rmethod
          = klass->engine->resolve_method(the_method,
                                          found_class,
                                          ((the_method->accflags
                                            & Modifier::STATIC) != 0));
-       pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
+       tags |= JV_CONSTANT_ResolvedFlag;
       }
       break;
     }
-  return pool->data[index];
+
+  write_cpool_entry (data, tags, pool, index);
+
+  return data;
 }
 
 // This function is used to lazily locate superclasses and
@@ -1728,13 +1752,15 @@ _Jv_Linker::ensure_class_linked (jclass klass)
       // Resolve the remaining constant pool entries.
       for (int index = 1; index < pool->size; ++index)
        {
-         if (pool->tags[index] == JV_CONSTANT_String)
-           {
-             jstring str;
+         jbyte tags;
+         _Jv_word data;
 
-             str = _Jv_NewStringUtf8Const (pool->data[index].utf8);
-             pool->data[index].o = str;
-             pool->tags[index] |= JV_CONSTANT_ResolvedFlag;
+         tags = read_cpool_entry (&data, pool, index);
+         if (tags == JV_CONSTANT_String)
+           {
+             data.o = _Jv_NewStringUtf8Const (data.utf8);
+             tags |= JV_CONSTANT_ResolvedFlag;
+             write_cpool_entry (data, tags, pool, index);
            }
        }