address CompiledIC::ic_destination() const {
assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");
if (!is_in_transition_state()) {
return _ic_call->destination();
} else {
return InlineCacheBuffer::ic_destination_for((CompiledIC *)this);
}
}
oop CompiledIC::cached_oop() const {
assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");
assert (!is_optimized(), "an optimized virtual call does not have a cached oop");
if (!is_in_transition_state()) {
oop data = *_oop_addr;
// If we let the oop value here be initialized to zero...
assert(data != NULL || Universe::non_oop_word() == NULL,
"no raw nulls in CompiledIC oops, because of patching races");
return (data == (oop)Universe::non_oop_word()) ? NULL : data;
} else {
return InlineCacheBuffer::cached_oop_for((CompiledIC *)this);
}
}
void CompiledIC::set_to_clean() {
assert(SafepointSynchronize::is_at_safepoint() || CompiledIC_lock->is_locked() , "MT-unsafe call");
if (TraceInlineCacheClearing || TraceICs) {
tty->print_cr("IC@" INTPTR_FORMAT ": set to clean", instruction_address());
print();
}
address entry;
#ifdef COMPILER1
entry = is_optimized() ?
Runtime1::entry_for(Runtime1::resolve_invoke_opt_virtual_id) :
Runtime1::entry_for(Runtime1::resolve_invokevirtual_id);
#else
entry =
is_optimized()
? OptoRuntime::resolve_opt_virtual_call_Java()
: OptoRuntime::resolve_virtual_call_Java();
#endif
// A zombie transition will always be safe, since the oop has already been set to NULL, so
// we only need to patch the destination
bool safe_transition = is_optimized() || SafepointSynchronize::is_at_safepoint();
if (safe_transition) {
if (!is_optimized()) set_cached_oop(NULL);
// Kill any leftover stub we might have too
if (is_in_transition_state()) {
ICStub* old_stub = ICStub_from_destination_address(stub_address());
old_stub->clear();
}
set_ic_destination(entry);
} else {
// Unsafe transition - create stub.
InlineCacheBuffer::create_transition_stub(this, NULL, entry);
}
// We can't check this anymore. With lazy deopt we could have already
// cleaned this IC entry before we even return. This is possible if
// we ran out of space in the inline cache buffer trying to do the
// set_next and we safepointed to free up space. This is a benign
// race because the IC entry was complete when we safepointed so
// cleaning it immediately is harmless.
// assert(is_clean(), "sanity check");
}
// Returns native address of 'call' instruction in inline-cache. Used by
// the InlineCacheBuffer when it needs to find the stub.
address CompiledIC::stub_address() const {
assert(is_in_transition_state(), "should only be called when we are in a transition state");
return _ic_call->destination();
}
void CompiledIC::set_to_monomorphic(CompiledICInfo& info) {
assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "");
// Updating a cache to the wrong entry can cause bugs that are very hard
// to track down - if cache entry gets invalid - we just clean it. In
// this way it is always the same code path that is responsible for
// updating and resolving an inline cache
//
// The above is no longer true. SharedRuntime::fixup_callers_callsite will change optimized
// callsites. In addition ic_miss code will update a site to monomorphic if it determines
// that an monomorphic call to the interpreter can now be monomorphic to compiled code.
//
// In both of these cases the only thing being modifed is the jump/call target and these
// transitions are mt_safe
Thread *thread = Thread::current();
if (info.to_interpreter()) {
// Call to interpreter
if (info.is_optimized() && is_optimized()) {
assert(is_clean(), "unsafe IC path");
MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
// the call analysis (callee structure) specifies that the call is optimized
// (either because of CHA or the static target is final)
// At code generation time, this call has been emitted as static call
// Call via stub
assert(info.cached_metadata() != NULL && info.cached_metadata()->is_method(), "sanity check");
CompiledStaticCall* csc = compiledStaticCall_at(instruction_address());
methodHandle method (thread, (Method*)info.cached_metadata());
csc->set_to_interpreted(method, info.entry());
if (TraceICs) {
ResourceMark rm(thread);
tty->print_cr ("IC@" INTPTR_FORMAT ": monomorphic to interpreter: %s",
p2i(instruction_address()),
method->print_value_string());
}
} else {
// Call via method-klass-holder
InlineCacheBuffer::create_transition_stub(this, info.claim_cached_icholder(), info.entry());
if (TraceICs) {
ResourceMark rm(thread);
tty->print_cr ("IC@" INTPTR_FORMAT ": monomorphic to interpreter via icholder ", p2i(instruction_address()));
}
}
} else {
// Call to compiled code
bool static_bound = info.is_optimized() || (info.cached_metadata() == NULL);
#ifdef ASSERT
CodeBlob* cb = CodeCache::find_blob_unsafe(info.entry());
assert (cb->is_nmethod(), "must be compiled!");
#endif /* ASSERT */
// This is MT safe if we come from a clean-cache and go through a
// non-verified entry point
bool safe = SafepointSynchronize::is_at_safepoint() ||
(!is_in_transition_state() && (info.is_optimized() || static_bound || is_clean()));
if (!safe) {
InlineCacheBuffer::create_transition_stub(this, info.cached_metadata(), info.entry());
} else {
if (is_optimized()) {
set_ic_destination(info.entry());
} else {
set_ic_destination_and_value(info.entry(), info.cached_metadata());
}
}
if (TraceICs) {
ResourceMark rm(thread);
assert(info.cached_metadata() == NULL || info.cached_metadata()->is_klass(), "must be");
tty->print_cr ("IC@" INTPTR_FORMAT ": monomorphic to compiled (rcvr klass) %s: %s",
p2i(instruction_address()),
((Klass*)info.cached_metadata())->print_value_string(),
(safe) ? "" : "via stub");
}
}
// We can't check this anymore. With lazy deopt we could have already
// cleaned this IC entry before we even return. This is possible if
// we ran out of space in the inline cache buffer trying to do the
// set_next and we safepointed to free up space. This is a benign
// race because the IC entry was complete when we safepointed so
// cleaning it immediately is harmless.
// assert(is_call_to_compiled() || is_call_to_interpreted(), "sanity check");
}
// Clears the IC stub if the compiled IC is in transition state
void CompiledIC::clear_ic_stub() {
if (is_in_transition_state()) {
ICStub* stub = ICStub_from_destination_address(stub_address());
stub->clear();
}
}