Mercurial > hg > truffle
diff src/share/vm/oops/cpCacheOop.cpp @ 6266:1d7922586cf6
7023639: JSR 292 method handle invocation needs a fast path for compiled code
6984705: JSR 292 method handle creation should not go through JNI
Summary: remove assembly code for JDK 7 chained method handles
Reviewed-by: jrose, twisti, kvn, mhaupt
Contributed-by: John Rose <john.r.rose@oracle.com>, Christian Thalinger <christian.thalinger@oracle.com>, Michael Haupt <michael.haupt@oracle.com>
author | twisti |
---|---|
date | Tue, 24 Jul 2012 10:51:00 -0700 |
parents | f096e1b74d85 |
children |
line wrap: on
line diff
--- a/src/share/vm/oops/cpCacheOop.cpp Mon Jul 23 13:04:59 2012 -0700 +++ b/src/share/vm/oops/cpCacheOop.cpp Tue Jul 24 10:51:00 2012 -0700 @@ -31,6 +31,7 @@ #include "oops/objArrayOop.hpp" #include "oops/oop.inline.hpp" #include "prims/jvmtiRedefineClassesTrace.hpp" +#include "prims/methodHandles.hpp" #include "runtime/handles.inline.hpp" @@ -44,68 +45,61 @@ void ConstantPoolCacheEntry::initialize_secondary_entry(int main_index) { assert(0 <= main_index && main_index < 0x10000, "sanity check"); - _indices = (main_index << 16); + _indices = (main_index << main_cp_index_bits); assert(main_entry_index() == main_index, ""); } -int ConstantPoolCacheEntry::as_flags(TosState state, bool is_final, - bool is_vfinal, bool is_volatile, - bool is_method_interface, bool is_method) { - int f = state; - - assert( state < number_of_states, "Invalid state in as_flags"); - - f <<= 1; - if (is_final) f |= 1; - f <<= 1; - if (is_vfinal) f |= 1; - f <<= 1; - if (is_volatile) f |= 1; - f <<= 1; - if (is_method_interface) f |= 1; - f <<= 1; - if (is_method) f |= 1; - f <<= ConstantPoolCacheEntry::hotSwapBit; +int ConstantPoolCacheEntry::make_flags(TosState state, + int option_bits, + int field_index_or_method_params) { + assert(state < number_of_states, "Invalid state in make_flags"); + int f = ((int)state << tos_state_shift) | option_bits | field_index_or_method_params; // Preserve existing flag bit values + // The low bits are a field offset, or else the method parameter size. #ifdef ASSERT - int old_state = ((_flags >> tosBits) & 0x0F); - assert(old_state == 0 || old_state == state, + TosState old_state = flag_state(); + assert(old_state == (TosState)0 || old_state == state, "inconsistent cpCache flags state"); #endif return (_flags | f) ; } void ConstantPoolCacheEntry::set_bytecode_1(Bytecodes::Code code) { + assert(!is_secondary_entry(), "must not overwrite main_entry_index"); #ifdef ASSERT // Read once. volatile Bytecodes::Code c = bytecode_1(); assert(c == 0 || c == code || code == 0, "update must be consistent"); #endif // Need to flush pending stores here before bytecode is written. - OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << 16)); + OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << bytecode_1_shift)); } void ConstantPoolCacheEntry::set_bytecode_2(Bytecodes::Code code) { + assert(!is_secondary_entry(), "must not overwrite main_entry_index"); #ifdef ASSERT // Read once. volatile Bytecodes::Code c = bytecode_2(); assert(c == 0 || c == code || code == 0, "update must be consistent"); #endif // Need to flush pending stores here before bytecode is written. - OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << 24)); + OrderAccess::release_store_ptr(&_indices, _indices | ((u_char)code << bytecode_2_shift)); } -// Atomically sets f1 if it is still NULL, otherwise it keeps the -// current value. -void ConstantPoolCacheEntry::set_f1_if_null_atomic(oop f1) { +// Sets f1, ordering with previous writes. +void ConstantPoolCacheEntry::release_set_f1(oop f1) { // Use barriers as in oop_store + assert(f1 != NULL, ""); oop* f1_addr = (oop*) &_f1; update_barrier_set_pre(f1_addr, f1); - void* result = Atomic::cmpxchg_ptr(f1, f1_addr, NULL); - bool success = (result == NULL); - if (success) { - update_barrier_set((void*) f1_addr, f1); - } + OrderAccess::release_store_ptr((intptr_t*)f1_addr, f1); + update_barrier_set((void*) f1_addr, f1); +} + +// Sets flags, but only if the value was previously zero. +bool ConstantPoolCacheEntry::init_flags_atomic(intptr_t flags) { + intptr_t result = Atomic::cmpxchg_ptr(flags, &_flags, 0); + return (result == 0); } #ifdef ASSERT @@ -135,17 +129,32 @@ bool is_volatile) { set_f1(field_holder()->java_mirror()); set_f2(field_offset); - assert(field_index <= field_index_mask, + assert((field_index & field_index_mask) == field_index, "field index does not fit in low flag bits"); - set_flags(as_flags(field_type, is_final, false, is_volatile, false, false) | - (field_index & field_index_mask)); + 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)); } -int ConstantPoolCacheEntry::field_index() const { - return (_flags & field_index_mask); +void ConstantPoolCacheEntry::set_parameter_size(int value) { + // This routine is called only in corner cases where the CPCE is not yet initialized. + // See AbstractInterpreter::deopt_continue_after_entry. + assert(_flags == 0 || parameter_size() == 0 || parameter_size() == value, + err_msg("size must not change: parameter_size=%d, value=%d", parameter_size(), value)); + // Setting the parameter size by itself is only safe if the + // current value of _flags is 0, otherwise another thread may have + // updated it and we don't want to overwrite that value. Don't + // bother trying to update it once it's nonzero but always make + // sure that the final parameter size agrees with what was passed. + if (_flags == 0) { + Atomic::cmpxchg_ptr((value & parameter_size_mask), &_flags, 0); + } + guarantee(parameter_size() == value, + err_msg("size must not change: parameter_size=%d, value=%d", parameter_size(), value)); } void ConstantPoolCacheEntry::set_method(Bytecodes::Code invoke_code, @@ -154,51 +163,51 @@ assert(!is_secondary_entry(), ""); assert(method->interpreter_entry() != NULL, "should have been set at this point"); assert(!method->is_obsolete(), "attempt to write obsolete method to cpCache"); - bool change_to_virtual = (invoke_code == Bytecodes::_invokeinterface); int byte_no = -1; - bool needs_vfinal_flag = false; + 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: - case Bytecodes::_invokeinterface: { + { if (method->can_be_statically_bound()) { - set_f2((intptr_t)method()); - needs_vfinal_flag = true; + // 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(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::_invokedynamic: // similar to _invokevirtual - if (TraceInvokeDynamic) { - tty->print_cr("InvokeDynamic set_method%s method="PTR_FORMAT" index=%d", - (is_secondary_entry() ? " secondary" : ""), - (intptr_t)method(), vtable_index); - method->print(); - this->print(tty, 0); } - assert(method->can_be_statically_bound(), "must be a MH invoker method"); - assert(_f2 >= constantPoolOopDesc::CPCACHE_INDEX_TAG, "BSM index initialized"); - // SystemDictionary::find_method_handle_invoke only caches - // methods which signature classes are on the boot classpath, - // otherwise the newly created method is returned. To avoid - // races in that case we store the first one coming in into the - // cp-cache atomically if it's still unset. - set_f1_if_null_atomic(method()); - needs_vfinal_flag = false; // _f2 is not an oop - assert(!is_vfinal(), "f2 not an oop"); - byte_no = 1; // coordinate this with bytecode_number & is_resolved - 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: + // 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; @@ -207,19 +216,14 @@ 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) { + 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 @@ -235,10 +239,11 @@ // Otherwise, the method needs to be reresolved with caller for each // interface call. if (method->is_public()) set_bytecode_1(invoke_code); - set_bytecode_2(Bytecodes::_invokevirtual); } else { - set_bytecode_2(invoke_code); + assert(invoke_code == Bytecodes::_invokevirtual, ""); } + // set up for invokevirtual, even if linking for invokeinterface also: + set_bytecode_2(Bytecodes::_invokevirtual); } else { ShouldNotReachHere(); } @@ -250,73 +255,129 @@ assert(!is_secondary_entry(), ""); klassOop interf = method->method_holder(); assert(instanceKlass::cast(interf)->is_interface(), "must be an interface"); + assert(!method->is_final_method(), "interfaces do not have final methods; cannot link to one here"); set_f1(interf); set_f2(index); - set_flags(as_flags(as_TosState(method->result_type()), method->is_final_method(), false, false, false, true) | method()->size_of_parameters()); + set_method_flags(as_TosState(method->result_type()), + 0, // no option bits + method()->size_of_parameters()); set_bytecode_1(Bytecodes::_invokeinterface); } -void ConstantPoolCacheEntry::initialize_bootstrap_method_index_in_cache(int bsm_cache_index) { - assert(!is_secondary_entry(), "only for JVM_CONSTANT_InvokeDynamic main entry"); - assert(_f2 == 0, "initialize once"); - assert(bsm_cache_index == (int)(u2)bsm_cache_index, "oob"); - set_f2(bsm_cache_index + constantPoolOopDesc::CPCACHE_INDEX_TAG); +void ConstantPoolCacheEntry::set_method_handle(methodHandle adapter, Handle appendix) { + assert(!is_secondary_entry(), ""); + set_method_handle_common(Bytecodes::_invokehandle, adapter, appendix); } -int ConstantPoolCacheEntry::bootstrap_method_index_in_cache() { - assert(!is_secondary_entry(), "only for JVM_CONSTANT_InvokeDynamic main entry"); - intptr_t bsm_cache_index = (intptr_t) _f2 - constantPoolOopDesc::CPCACHE_INDEX_TAG; - assert(bsm_cache_index == (intptr_t)(u2)bsm_cache_index, "oob"); - return (int) bsm_cache_index; +void ConstantPoolCacheEntry::set_dynamic_call(methodHandle adapter, Handle appendix) { + assert(is_secondary_entry(), ""); + set_method_handle_common(Bytecodes::_invokedynamic, adapter, appendix); } -void ConstantPoolCacheEntry::set_dynamic_call(Handle call_site, methodHandle signature_invoker) { - assert(is_secondary_entry(), ""); - // NOTE: it's important that all other values are set before f1 is - // set since some users short circuit on f1 being set - // (i.e. non-null) and that may result in uninitialized values for - // other racing threads (e.g. flags). - int param_size = signature_invoker->size_of_parameters(); - assert(param_size >= 1, "method argument size must include MH.this"); - param_size -= 1; // do not count MH.this; it is not stacked for invokedynamic - bool is_final = true; - assert(signature_invoker->is_final_method(), "is_final"); - int flags = as_flags(as_TosState(signature_invoker->result_type()), is_final, false, false, false, true) | param_size; - assert(_flags == 0 || _flags == flags, "flags should be the same"); - set_flags(flags); - // do not do set_bytecode on a secondary CP cache entry - //set_bytecode_1(Bytecodes::_invokedynamic); - set_f1_if_null_atomic(call_site()); // This must be the last one to set (see NOTE above)! +void ConstantPoolCacheEntry::set_method_handle_common(Bytecodes::Code invoke_code, methodHandle adapter, Handle appendix) { + // 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 on the first + // write, to flags, using a compare/exchange. + // A losing writer must spin until the winner writes f1, + // so that when he returns, he can use the linked cache entry. + + bool has_appendix = appendix.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(); + } + + bool owner = + init_method_flags_atomic(as_TosState(adapter->result_type()), + ((has_appendix ? 1 : 0) << has_appendix_shift) | + ( 1 << is_vfinal_shift) | + ( 1 << is_final_shift), + adapter->size_of_parameters()); + if (!owner) { + while (is_f1_null()) { + // Pause momentarily on a low-level lock, to allow racing thread to win. + MutexLockerEx mu(Patching_lock, Mutex::_no_safepoint_check_flag); + os::yield(); + } + return; + } + + if (TraceInvokeDynamic) { + tty->print_cr("set_method_handle bc=%d appendix="PTR_FORMAT"%s method="PTR_FORMAT" ", + invoke_code, + (intptr_t)appendix(), (has_appendix ? "" : " (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()); + 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); + } } - -methodOop ConstantPoolCacheEntry::get_method_if_resolved(Bytecodes::Code invoke_code, constantPoolHandle cpool) { - assert(invoke_code > (Bytecodes::Code)0, "bad query"); +methodOop ConstantPoolCacheEntry::method_if_resolved(constantPoolHandle cpool) { if (is_secondary_entry()) { - return cpool->cache()->entry_at(main_entry_index())->get_method_if_resolved(invoke_code, cpool); + if (!is_f1_null()) + return f2_as_vfinal_method(); + return NULL; } // Decode the action of set_method and set_interface_call - if (bytecode_1() == invoke_code) { + Bytecodes::Code invoke_code = bytecode_1(); + if (invoke_code != (Bytecodes::Code)0) { oop f1 = _f1; if (f1 != NULL) { switch (invoke_code) { case Bytecodes::_invokeinterface: assert(f1->is_klass(), ""); - return klassItable::method_for_itable_index(klassOop(f1), (int) f2()); + return klassItable::method_for_itable_index(klassOop(f1), f2_as_index()); case Bytecodes::_invokestatic: case Bytecodes::_invokespecial: + assert(!has_appendix(), ""); assert(f1->is_method(), ""); return methodOop(f1); } } } - if (bytecode_2() == invoke_code) { + invoke_code = bytecode_2(); + if (invoke_code != (Bytecodes::Code)0) { switch (invoke_code) { case Bytecodes::_invokevirtual: if (is_vfinal()) { // invokevirtual - methodOop m = methodOop((intptr_t) f2()); + methodOop m = f2_as_vfinal_method(); assert(m->is_method(), ""); return m; } else { @@ -325,16 +386,19 @@ klassOop klass = cpool->resolved_klass_at(holder_index); if (!Klass::cast(klass)->oop_is_instance()) klass = SystemDictionary::Object_klass(); - return instanceKlass::cast(klass)->method_at_vtable((int) f2()); + return instanceKlass::cast(klass)->method_at_vtable(f2_as_index()); } } + break; + case Bytecodes::_invokehandle: + case Bytecodes::_invokedynamic: + return f2_as_vfinal_method(); } } return NULL; } - class LocalOopClosure: public OopClosure { private: void (*_f)(oop*); @@ -419,9 +483,10 @@ methodOop new_method, bool * trace_name_printed) { if (is_vfinal()) { - // virtual and final so f2() contains method ptr instead of vtable index - if (f2() == (intptr_t)old_method) { + // virtual and final so _f2 contains method ptr instead of vtable index + if (f2_as_vfinal_method() == old_method) { // match old_method so need an update + // NOTE: can't use set_f2_as_vfinal_method as it asserts on different values _f2 = (intptr_t)new_method; if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) { if (!(*trace_name_printed)) { @@ -479,16 +544,17 @@ methodOop m = NULL; if (is_vfinal()) { // virtual and final so _f2 contains method ptr instead of vtable index - m = (methodOop)_f2; - } else if ((oop)_f1 == NULL) { + m = f2_as_vfinal_method(); + } else if (is_f1_null()) { // NULL _f1 means this is a virtual entry so also not interesting return false; } else { - if (!((oop)_f1)->is_method()) { + oop f1 = _f1; // _f1 is volatile + if (!f1->is_method()) { // _f1 can also contain a klassOop for an interface return false; } - m = (methodOop)_f1; + m = f1_as_method(); } assert(m != NULL && m->is_method(), "sanity check");