// Check if there are any JVM TI prefixes which have been applied to the native method name.
// If any are found, remove them before attemping the look up of the
// native implementation again.
// See SetNativeMethodPrefix in the JVM TI Spec for more details.
address NativeLookup::lookup_entry_prefixed(methodHandle method, bool& in_base_library, TRAPS) {
ResourceMark rm(THREAD);
int prefix_count;
char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
char* in_name = method->name()->as_C_string();
char* wrapper_name = in_name;
// last applied prefix will be first -- go backwards
for (int i = prefix_count-1; i >= 0; i--) {
char* prefix = prefixes[i];
size_t prefix_len = strlen(prefix);
if (strncmp(prefix, wrapper_name, prefix_len) == 0) {
// has this prefix remove it
wrapper_name += prefix_len;
}
}
if (wrapper_name != in_name) {
// we have a name for a wrapping method
int wrapper_name_len = (int)strlen(wrapper_name);
TempNewSymbol wrapper_symbol = SymbolTable::probe(wrapper_name, wrapper_name_len);
if (wrapper_symbol != NULL) {
KlassHandle kh(method->method_holder());
methodOop wrapper_method = Klass::cast(kh())->lookup_method(wrapper_symbol,
method->signature());
if (wrapper_method != NULL && !wrapper_method->is_native()) {
// we found a wrapper method, use its native entry
method->set_is_prefixed_native();
return lookup_entry(wrapper_method, in_base_library, THREAD);
}
}
}
return NULL;
}
VerificationType StackMapFrame::set_locals_from_arg(
const methodHandle m, VerificationType thisKlass, TRAPS) {
SignatureStream ss(m->signature());
int init_local_num = 0;
if (!m->is_static()) {
init_local_num++;
// add one extra argument for instance method
if (m->name() == vmSymbols::object_initializer_name() &&
thisKlass.name() != vmSymbols::java_lang_Object()) {
_locals[0] = VerificationType::uninitialized_this_type();
_flags |= FLAG_THIS_UNINIT;
} else {
_locals[0] = thisKlass;
}
}
// local num may be greater than size of parameters because long/double occupies two slots
while(!ss.at_return_type()) {
init_local_num += _verifier->change_sig_to_verificationType(
&ss, &_locals[init_local_num],
CHECK_VERIFY_(verifier(), VerificationType::bogus_type()));
ss.next();
}
_locals_size = init_local_num;
switch (ss.type()) {
case T_OBJECT:
case T_ARRAY:
{
Symbol* sig = ss.as_symbol(CHECK_(VerificationType::bogus_type()));
// Create another symbol to save as signature stream unreferences
// this symbol.
Symbol* sig_copy =
verifier()->create_temporary_symbol(sig, 0, sig->utf8_length(),
CHECK_(VerificationType::bogus_type()));
assert(sig_copy == sig, "symbols don't match");
return VerificationType::reference_type(sig_copy);
}
case T_INT: return VerificationType::integer_type();
case T_BYTE: return VerificationType::byte_type();
case T_CHAR: return VerificationType::char_type();
case T_SHORT: return VerificationType::short_type();
case T_BOOLEAN: return VerificationType::boolean_type();
case T_FLOAT: return VerificationType::float_type();
case T_DOUBLE: return VerificationType::double_type();
case T_LONG: return VerificationType::long_type();
case T_VOID: return VerificationType::bogus_type();
default:
ShouldNotReachHere();
}
return VerificationType::bogus_type();
}
void JavaCalls::call_default_constructor(JavaThread* thread, methodHandle method, Handle receiver, TRAPS) {
assert(method->name() == vmSymbols::object_initializer_name(), "Should only be called for default constructor");
assert(method->signature() == vmSymbols::void_method_signature(), "Should only be called for default constructor");
InstanceKlass* ik = method->method_holder();
if (ik->is_initialized() && ik->has_vanilla_constructor()) {
// safe to skip constructor call
} else {
static JavaValue result(T_VOID);
JavaCallArguments args(receiver);
call(&result, method, &args, CHECK);
}
}
address NativeLookup::lookup(methodHandle method, bool& in_base_library, TRAPS) {
if (!method->has_native_function()) {
address entry = lookup_base(method, in_base_library, CHECK_NULL);
method->set_native_function(entry,
Method::native_bind_event_is_interesting);
// -verbose:jni printing
if (PrintJNIResolving) {
ResourceMark rm(THREAD);
tty->print_cr("[Dynamic-linking native method %s.%s ... JNI]",
method->method_holder()->external_name(),
method->name()->as_C_string());
}
}
return method->native_function();
}
/**
* 为给定的本地java方法寻找对应的函数入口地址
*/
address NativeLookup::lookup(methodHandle method, bool& in_base_library, TRAPS) {
if (!method->has_native_function()) {
printf("%s[%d] [tid: %lu]: 试图查找本地方法[%s.%s]..\n", __FILE__, __LINE__, pthread_self(), Klass::cast(method->method_holder())->external_name(), method->name()->as_C_string());
address entry = lookup_base(method, in_base_library, CHECK_NULL);
method->set_native_function(entry, methodOopDesc::native_bind_event_is_interesting);
// -verbose:jni printing
if (PrintJNIResolving) {
ResourceMark rm(THREAD);
tty->print_cr("[Dynamic-linking native method %s.%s ... JNI]",
Klass::cast(method->method_holder())->external_name(),
method->name()->as_C_string());
}
}
return method->native_function();
}
address NativeLookup::lookup_style(methodHandle method, char* pure_name, const char* long_name, int args_size, bool os_style, bool& in_base_library, TRAPS) {
address entry;
// Compute complete JNI name for style
stringStream st;
if (os_style) os::print_jni_name_prefix_on(&st, args_size);
st.print_raw(pure_name);
st.print_raw(long_name);
if (os_style) os::print_jni_name_suffix_on(&st, args_size);
char* jni_name = st.as_string();
// If the loader is null we have a system class, so we attempt a lookup in
// the native Java library. This takes care of any bootstrapping problems.
// Note: It is critical for bootstrapping that Java_java_lang_ClassLoader_00024NativeLibrary_find
// gets found the first time around - otherwise an infinite loop can occure. This is
// another VM/library dependency
Handle loader(THREAD,
instanceKlass::cast(method->method_holder())->class_loader());
if (loader.is_null()) {
entry = lookup_special_native(jni_name);
if (entry == NULL) {
printf("%s[%d] [tid: %lu]: 试图从动态链接库[libjava.so]中查找本地方法[%s.%s]..\n", __FILE__, __LINE__, pthread_self(), Klass::cast(method->method_holder())->external_name(), method->name()->as_C_string());
entry = (address) os::dll_lookup(os::native_java_library(), jni_name);
}
if (entry != NULL) {
in_base_library = true;
return entry;
}
}
// Otherwise call static method findNative in ClassLoader
KlassHandle klass (THREAD, SystemDictionary::ClassLoader_klass());
Handle name_arg = java_lang_String::create_from_str(jni_name, CHECK_NULL);
JavaValue result(T_LONG);
printf("%s[%d] [tid: %lu]: 试图调用静态方法[%s]来查找本地方法[%s.%s]..\n", __FILE__, __LINE__, pthread_self(), vmSymbols::findNative_name()->as_C_string(), Klass::cast(method->method_holder())->external_name(), method->name()->as_C_string());
JavaCalls::call_static(&result,
klass,
vmSymbols::findNative_name(),
vmSymbols::classloader_string_long_signature(),
// Arguments
loader,
name_arg,
CHECK_NULL);
entry = (address) (intptr_t) result.get_jlong();
if (entry == NULL) {
// findNative didn't find it, if there are any agent libraries look in them
AgentLibrary* agent;
for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
printf("%s[%d] [tid: %lu]: 试图从动态链接库[%s]中查找本地方法[%s.%s]..\n", __FILE__, __LINE__, pthread_self(), agent->name(), Klass::cast(method->method_holder())->external_name(), method->name()->as_C_string());
entry = (address) os::dll_lookup(agent->os_lib(), jni_name);
if (entry != NULL) {
return entry;
}
}
}
return entry;
}