// Return true if the interpreter can prove that the given bytecode has
// not yet been executed (in Java semantics, not in actual operation).
bool AbstractInterpreter::is_not_reached(methodHandle method, int bci) {
Bytecodes::Code code = method()->code_at(bci);
if (!Bytecodes::must_rewrite(code)) {
// might have been reached
return false;
}
// the bytecode might not be rewritten if the method is an accessor, etc.
address ientry = method->interpreter_entry();
if (ientry != entry_for_kind(AbstractInterpreter::zerolocals) &&
ientry != entry_for_kind(AbstractInterpreter::zerolocals_synchronized))
return false; // interpreter does not run this method!
// otherwise, we can be sure this bytecode has never been executed
return true;
}
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));
}