// Note that concurrent update of both bytecodes can leave one of them
// reset to zero. This is harmless; the interpreter will simply re-resolve
// the damaged entry. More seriously, the memory synchronization is needed
// to flush other fields (f1, f2) completely to memory before the bytecodes
// are updated, lest other processors see a non-zero bytecode but zero f1/f2.
void ConstantPoolCacheEntry::set_field(Bytecodes::Code get_code,
Bytecodes::Code put_code,
KlassHandle field_holder,
int field_index,
int field_offset,
TosState field_type,
bool is_final,
bool is_volatile) {
set_f1(field_holder());
set_f2(field_offset);
assert(field_index <= 0xFFFF, "field index does not fit in low flag bits");
set_flags(as_flags(field_type, is_final, false, is_volatile, false, false) | (field_index & 0xFFFF));
set_bytecode_1(get_code);
set_bytecode_2(put_code);
verify(tty);
}
// Note that concurrent update of both bytecodes can leave one of them
// reset to zero. This is harmless; the interpreter will simply re-resolve
// the damaged entry. More seriously, the memory synchronization is needed
// to flush other fields (f1, f2) completely to memory before the bytecodes
// are updated, lest other processors see a non-zero bytecode but zero f1/f2.
void ConstantPoolCacheEntry::set_field(Bytecodes::Code get_code,
Bytecodes::Code put_code,
KlassHandle field_holder,
int field_index,
int field_offset,
TosState field_type,
bool is_final,
bool is_volatile) {
set_f1(field_holder()->java_mirror());
set_f2(field_offset);
assert((field_index & field_index_mask) == field_index,
"field index does not fit in low flag bits");
set_field_flags(field_type,
((is_volatile ? 1 : 0) << is_volatile_shift) |
((is_final ? 1 : 0) << is_final_shift),
field_index);
set_bytecode_1(get_code);
set_bytecode_2(put_code);
NOT_PRODUCT(verify(tty));
}
void ConstantPoolCacheEntry::set_method(Bytecodes::Code invoke_code,
methodHandle method,
int vtable_index) {
assert(method->interpreter_entry() != NULL, "should have been set at this point");
assert(!method->is_old_version(), "attempt to write old method to cpCache");
bool change_to_virtual = (invoke_code == Bytecodes::_invokeinterface);
int byte_no = -1;
bool needs_vfinal_flag = false;
switch (invoke_code) {
case Bytecodes::_invokevirtual:
case Bytecodes::_invokeinterface: {
if (Klass::can_be_statically_bound(method())) {
set_f2((intptr_t)method());
needs_vfinal_flag = true;
} else {
set_f2(vtable_index);
}
byte_no = 2;
break;
}
case Bytecodes::_invokespecial:
// Preserve the value of the vfinal flag on invokevirtual bytecode
// which may be shared with this constant pool cache entry.
needs_vfinal_flag = is_resolved(Bytecodes::_invokevirtual) && is_vfinal();
// fall through
case Bytecodes::_invokestatic:
set_f1(method());
byte_no = 1;
break;
default:
ShouldNotReachHere();
break;
}
set_flags(as_flags(as_TosState(method->result_type()),
method->is_final_method(),
needs_vfinal_flag,
false,
change_to_virtual,
true)|
method()->size_of_parameters());
// Note: byte_no also appears in TemplateTable::resolve.
if (byte_no == 1) {
set_bytecode_1(invoke_code);
} else if (byte_no == 2) {
if (change_to_virtual) {
// NOTE: THIS IS A HACK - BE VERY CAREFUL!!!
//
// Workaround for the case where we encounter an invokeinterface, but we
// should really have an _invokevirtual since the resolved method is a
// virtual method in java.lang.Object. This is a corner case in the spec
// but is presumably legal. javac does not generate this code.
//
// We set bytecode_1() to _invokeinterface, because that is the
// bytecode # used by the interpreter to see if it is resolved.
// We set bytecode_2() to _invokevirtual.
// See also interpreterRuntime.cpp. (8/25/2000)
set_bytecode_1(invoke_code);
set_bytecode_2(Bytecodes::_invokevirtual);
} else {
set_bytecode_2(invoke_code);
}
} else {
ShouldNotReachHere();
}
verify(tty);
}
void ConstantPoolCacheEntry::set_direct_or_vtable_call(Bytecodes::Code invoke_code,
methodHandle method,
int vtable_index) {
bool is_vtable_call = (vtable_index >= 0); // FIXME: split this method on this boolean
assert(method->interpreter_entry() != NULL, "should have been set at this point");
assert(!method->is_obsolete(), "attempt to write obsolete method to cpCache");
int byte_no = -1;
bool change_to_virtual = false;
switch (invoke_code) {
case Bytecodes::_invokeinterface:
// We get here from InterpreterRuntime::resolve_invoke when an invokeinterface
// instruction somehow links to a non-interface method (in Object).
// In that case, the method has no itable index and must be invoked as a virtual.
// Set a flag to keep track of this corner case.
change_to_virtual = true;
// ...and fall through as if we were handling invokevirtual:
case Bytecodes::_invokevirtual:
{
if (!is_vtable_call) {
assert(method->can_be_statically_bound(), "");
// set_f2_as_vfinal_method checks if is_vfinal flag is true.
set_method_flags(as_TosState(method->result_type()),
( 1 << is_vfinal_shift) |
((method->is_final_method() ? 1 : 0) << is_final_shift) |
((change_to_virtual ? 1 : 0) << is_forced_virtual_shift),
method()->size_of_parameters());
set_f2_as_vfinal_method(method());
} else {
assert(!method->can_be_statically_bound(), "");
assert(vtable_index >= 0, "valid index");
assert(!method->is_final_method(), "sanity");
set_method_flags(as_TosState(method->result_type()),
((change_to_virtual ? 1 : 0) << is_forced_virtual_shift),
method()->size_of_parameters());
set_f2(vtable_index);
}
byte_no = 2;
break;
}
case Bytecodes::_invokespecial:
case Bytecodes::_invokestatic:
assert(!is_vtable_call, "");
// Note: Read and preserve the value of the is_vfinal flag on any
// invokevirtual bytecode shared with this constant pool cache entry.
// It is cheap and safe to consult is_vfinal() at all times.
// Once is_vfinal is set, it must stay that way, lest we get a dangling oop.
set_method_flags(as_TosState(method->result_type()),
((is_vfinal() ? 1 : 0) << is_vfinal_shift) |
((method->is_final_method() ? 1 : 0) << is_final_shift),
method()->size_of_parameters());
set_f1(method());
byte_no = 1;
break;
default:
ShouldNotReachHere();
break;
}
// Note: byte_no also appears in TemplateTable::resolve.
if (byte_no == 1) {
assert(invoke_code != Bytecodes::_invokevirtual &&
invoke_code != Bytecodes::_invokeinterface, "");
set_bytecode_1(invoke_code);
} else if (byte_no == 2) {
if (change_to_virtual) {
assert(invoke_code == Bytecodes::_invokeinterface, "");
// NOTE: THIS IS A HACK - BE VERY CAREFUL!!!
//
// Workaround for the case where we encounter an invokeinterface, but we
// should really have an _invokevirtual since the resolved method is a
// virtual method in java.lang.Object. This is a corner case in the spec
// but is presumably legal. javac does not generate this code.
//
// We set bytecode_1() to _invokeinterface, because that is the
// bytecode # used by the interpreter to see if it is resolved.
// We set bytecode_2() to _invokevirtual.
// See also interpreterRuntime.cpp. (8/25/2000)
// Only set resolved for the invokeinterface case if method is public.
// Otherwise, the method needs to be reresolved with caller for each
// interface call.
if (method->is_public()) set_bytecode_1(invoke_code);
} else {
assert(invoke_code == Bytecodes::_invokevirtual, "");
}
// set up for invokevirtual, even if linking for invokeinterface also:
set_bytecode_2(Bytecodes::_invokevirtual);
} else {
ShouldNotReachHere();
}
NOT_PRODUCT(verify(tty));
}
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);
}
}
