void ConstantPoolCacheEntry::set_method_handle_common(constantPoolHandle cpool,
Bytecodes::Code invoke_code,
const CallInfo &call_info) {
// NOTE: This CPCE can be the subject of data races.
// There are three words to update: flags, refs[f2], f1 (in that order).
// Writers must store all other values before f1.
// Readers must test f1 first for non-null before reading other fields.
// Competing writers must acquire exclusive access via a lock.
// A losing writer waits on the lock until the winner writes f1 and leaves
// the lock, so that when the losing writer returns, he can use the linked
// cache entry.
MonitorLockerEx ml(cpool->lock());
if (!is_f1_null()) {
return;
}
const methodHandle adapter = call_info.resolved_method();
const Handle appendix = call_info.resolved_appendix();
const Handle method_type = call_info.resolved_method_type();
const bool has_appendix = appendix.not_null();
const bool has_method_type = method_type.not_null();
// Write the flags.
set_method_flags(as_TosState(adapter->result_type()),
((has_appendix ? 1 : 0) << has_appendix_shift ) |
((has_method_type ? 1 : 0) << has_method_type_shift) |
( 1 << is_final_shift ),
adapter->size_of_parameters());
if (TraceInvokeDynamic) {
tty->print_cr("set_method_handle bc=%d appendix="PTR_FORMAT"%s method_type="PTR_FORMAT"%s method="PTR_FORMAT" ",
invoke_code,
(void *)appendix(), (has_appendix ? "" : " (unused)"),
(void *)method_type(), (has_method_type ? "" : " (unused)"),
(intptr_t)adapter());
adapter->print();
if (has_appendix) appendix()->print();
}
// Method handle invokes and invokedynamic sites use both cp cache words.
// refs[f2], if not null, contains a value passed as a trailing argument to the adapter.
// In the general case, this could be the call site's MethodType,
// for use with java.lang.Invokers.checkExactType, or else a CallSite object.
// f1 contains the adapter method which manages the actual call.
// In the general case, this is a compiled LambdaForm.
// (The Java code is free to optimize these calls by binding other
// sorts of methods and appendices to call sites.)
// JVM-level linking is via f1, as if for invokespecial, and signatures are erased.
// The appendix argument (if any) is added to the signature, and is counted in the parameter_size bits.
// Even with the appendix, the method will never take more than 255 parameter slots.
//
// This means that given a call site like (List)mh.invoke("foo"),
// the f1 method has signature '(Ljl/Object;Ljl/invoke/MethodType;)Ljl/Object;',
// not '(Ljava/lang/String;)Ljava/util/List;'.
// The fact that String and List are involved is encoded in the MethodType in refs[f2].
// This allows us to create fewer method oops, while keeping type safety.
//
objArrayHandle resolved_references = cpool->resolved_references();
// Store appendix, if any.
if (has_appendix) {
const int appendix_index = f2_as_index() + _indy_resolved_references_appendix_offset;
assert(appendix_index >= 0 && appendix_index < resolved_references->length(), "oob");
assert(resolved_references->obj_at(appendix_index) == NULL, "init just once");
resolved_references->obj_at_put(appendix_index, appendix());
}
// Store MethodType, if any.
if (has_method_type) {
const int method_type_index = f2_as_index() + _indy_resolved_references_method_type_offset;
assert(method_type_index >= 0 && method_type_index < resolved_references->length(), "oob");
assert(resolved_references->obj_at(method_type_index) == NULL, "init just once");
resolved_references->obj_at_put(method_type_index, method_type());
}
release_set_f1(adapter()); // This must be the last one to set (see NOTE above)!
// The interpreter assembly code does not check byte_2,
// but it is used by is_resolved, method_if_resolved, etc.
set_bytecode_1(invoke_code);
NOT_PRODUCT(verify(tty));
if (TraceInvokeDynamic) {
this->print(tty, 0);
}
}
void ConstantPoolCacheEntry::set_method_handle_common(constantPoolHandle cpool,
Bytecodes::Code invoke_code,
methodHandle adapter,
Handle appendix, Handle method_type) {
// NOTE: This CPCE can be the subject of data races.
// There are three words to update: flags, f2, f1 (in that order).
// Writers must store all other values before f1.
// Readers must test f1 first for non-null before reading other fields.
// Competing writers must acquire exclusive access via a lock.
// A losing writer waits on the lock until the winner writes f1 and leaves
// the lock, so that when the losing writer returns, he can use the linked
// cache entry.
Thread* THREAD = Thread::current();
ObjectLocker ol(cpool, THREAD);
if (!is_f1_null()) {
return;
}
const bool has_appendix = appendix.not_null();
const bool has_method_type = method_type.not_null();
if (!has_appendix) {
// The extra argument is not used, but we need a non-null value to signify linkage state.
// Set it to something benign that will never leak memory.
appendix = Universe::void_mirror();
}
// Write the flags.
set_method_flags(as_TosState(adapter->result_type()),
((has_appendix ? 1 : 0) << has_appendix_shift) |
((has_method_type ? 1 : 0) << has_method_type_shift) |
( 1 << is_vfinal_shift) |
( 1 << is_final_shift),
adapter->size_of_parameters());
if (TraceInvokeDynamic) {
tty->print_cr("set_method_handle bc=%d appendix="PTR_FORMAT"%s method_type="PTR_FORMAT"%s method="PTR_FORMAT" ",
invoke_code,
(intptr_t)appendix(), (has_appendix ? "" : " (unused)"),
(intptr_t)method_type(), (has_method_type ? "" : " (unused)"),
(intptr_t)adapter());
adapter->print();
if (has_appendix) appendix()->print();
}
// Method handle invokes and invokedynamic sites use both cp cache words.
// f1, if not null, contains a value passed as a trailing argument to the adapter.
// In the general case, this could be the call site's MethodType,
// for use with java.lang.Invokers.checkExactType, or else a CallSite object.
// f2 contains the adapter method which manages the actual call.
// In the general case, this is a compiled LambdaForm.
// (The Java code is free to optimize these calls by binding other
// sorts of methods and appendices to call sites.)
// JVM-level linking is via f2, as if for invokevfinal, and signatures are erased.
// The appendix argument (if any) is added to the signature, and is counted in the parameter_size bits.
// In principle this means that the method (with appendix) could take up to 256 parameter slots.
//
// This means that given a call site like (List)mh.invoke("foo"),
// the f2 method has signature '(Ljl/Object;Ljl/invoke/MethodType;)Ljl/Object;',
// not '(Ljava/lang/String;)Ljava/util/List;'.
// The fact that String and List are involved is encoded in the MethodType in f1.
// This allows us to create fewer method oops, while keeping type safety.
//
set_f2_as_vfinal_method(adapter());
// Store MethodType, if any.
if (has_method_type) {
ConstantPoolCacheEntry* e2 = cpool->cache()->find_secondary_entry_for(this);
// Write the flags.
e2->set_method_flags(as_TosState(adapter->result_type()),
((has_method_type ? 1 : 0) << has_method_type_shift) |
( 1 << is_vfinal_shift) |
( 1 << is_final_shift),
adapter->size_of_parameters());
e2->release_set_f1(method_type());
}
assert(appendix.not_null(), "needed for linkage state");
release_set_f1(appendix()); // This must be the last one to set (see NOTE above)!
if (!is_secondary_entry()) {
// The interpreter assembly code does not check byte_2,
// but it is used by is_resolved, method_if_resolved, etc.
set_bytecode_2(invoke_code);
}
NOT_PRODUCT(verify(tty));
if (TraceInvokeDynamic) {
this->print(tty, 0);
}
}