8214936: assert(_needs_refill == 0) failed: Forgot to handle a failed IC transition requiring IC stubs
Reviewed-by: kvn, thartmann, pliden
--- a/src/hotspot/share/code/compiledMethod.cpp Fri Dec 07 11:15:18 2018 +0100
+++ b/src/hotspot/share/code/compiledMethod.cpp Fri Dec 07 13:15:35 2018 +0100
@@ -556,6 +556,7 @@
void CompiledMethod::cleanup_inline_caches(bool clean_all) {
for (;;) {
+ ICRefillVerifier ic_refill_verifier;
{ CompiledICLocker ic_locker(this);
if (cleanup_inline_caches_impl(false, clean_all)) {
return;
--- a/src/hotspot/share/code/icBuffer.cpp Fri Dec 07 11:15:18 2018 +0100
+++ b/src/hotspot/share/code/icBuffer.cpp Fri Dec 07 13:15:35 2018 +0100
@@ -38,6 +38,7 @@
#include "runtime/handles.inline.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/stubRoutines.hpp"
+#include "runtime/thread.hpp"
DEF_STUB_INTERFACE(ICStub);
@@ -45,7 +46,40 @@
CompiledICHolder* InlineCacheBuffer::_pending_released = NULL;
int InlineCacheBuffer::_pending_count = 0;
-DEBUG_ONLY(volatile int InlineCacheBuffer::_needs_refill = 0;)
+
+#ifdef ASSERT
+ICRefillVerifier::ICRefillVerifier()
+ : _refill_requested(false),
+ _refill_remembered(false)
+{
+ Thread* thread = Thread::current();
+ assert(thread->missed_ic_stub_refill_mark() == NULL, "nesting not supported");
+ thread->set_missed_ic_stub_refill_mark(this);
+}
+
+ICRefillVerifier::~ICRefillVerifier() {
+ assert(!_refill_requested || _refill_remembered,
+ "Forgot to refill IC stubs after failed IC transition");
+ Thread::current()->set_missed_ic_stub_refill_mark(NULL);
+}
+
+ICRefillVerifierMark::ICRefillVerifierMark(ICRefillVerifier* verifier) {
+ Thread* thread = Thread::current();
+ assert(thread->missed_ic_stub_refill_mark() == NULL, "nesting not supported");
+ thread->set_missed_ic_stub_refill_mark(this);
+}
+
+ICRefillVerifierMark::~ICRefillVerifierMark() {
+ Thread::current()->set_missed_ic_stub_refill_mark(NULL);
+}
+
+static ICRefillVerifier* current_ic_refill_verifier() {
+ Thread* current = Thread::current();
+ ICRefillVerifier* verifier = reinterpret_cast<ICRefillVerifier*>(current->missed_ic_stub_refill_mark());
+ assert(verifier != NULL, "need a verifier for safety");
+ return verifier;
+}
+#endif
void ICStub::finalize() {
if (!is_empty()) {
@@ -117,7 +151,10 @@
void InlineCacheBuffer::refill_ic_stubs() {
- DEBUG_ONLY(Atomic::store(0, &_needs_refill));
+#ifdef ASSERT
+ ICRefillVerifier* verifier = current_ic_refill_verifier();
+ verifier->request_remembered();
+#endif
// we ran out of inline cache buffer space; must enter safepoint.
// We do this by forcing a safepoint
EXCEPTION_MARK;
@@ -135,8 +172,6 @@
void InlineCacheBuffer::update_inline_caches() {
- assert(_needs_refill == 0,
- "Forgot to handle a failed IC transition requiring IC stubs");
if (buffer()->number_of_stubs() > 0) {
if (TraceICBuffer) {
tty->print_cr("[updating inline caches with %d stubs]", buffer()->number_of_stubs());
@@ -161,7 +196,6 @@
InlineCacheBuffer::initialize();
}
-
bool InlineCacheBuffer::create_transition_stub(CompiledIC *ic, void* cached_value, address entry) {
assert(!SafepointSynchronize::is_at_safepoint(), "should not be called during a safepoint");
assert(CompiledICLocker::is_safe(ic->instruction_address()), "mt unsafe call");
@@ -173,7 +207,10 @@
// allocate and initialize new "out-of-line" inline-cache
ICStub* ic_stub = new_ic_stub();
if (ic_stub == NULL) {
- DEBUG_ONLY(Atomic::inc(&_needs_refill));
+#ifdef ASSERT
+ ICRefillVerifier* verifier = current_ic_refill_verifier();
+ verifier->request_refill();
+#endif
return false;
}
--- a/src/hotspot/share/code/icBuffer.hpp Fri Dec 07 11:15:18 2018 +0100
+++ b/src/hotspot/share/code/icBuffer.hpp Fri Dec 07 13:15:35 2018 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -29,7 +29,9 @@
#include "code/stubs.hpp"
#include "interpreter/bytecodes.hpp"
#include "memory/allocation.hpp"
+#include "runtime/safepointVerifiers.hpp"
#include "utilities/align.hpp"
+#include "utilities/debug.hpp"
#include "utilities/macros.hpp"
//
@@ -93,6 +95,43 @@
return stub;
}
+#ifdef ASSERT
+// The ICRefillVerifier class is a stack allocated RAII object used to
+// detect if a failed IC transition that required IC stub refilling has
+// been accidentally missed. It is up to the caller to in that case
+// refill IC stubs.
+class ICRefillVerifier: StackObj {
+ bool _refill_requested;
+ bool _refill_remembered;
+
+ public:
+ ICRefillVerifier();
+ ~ICRefillVerifier();
+
+ void request_refill() { _refill_requested = true; }
+ void request_remembered() { _refill_remembered = true; }
+};
+
+// The ICRefillVerifierMark is used to set the thread's current
+// ICRefillVerifier to a provided one. This is useful in particular
+// when transitioning IC stubs in parallel and refilling from the
+// master thread invoking the IC stub transitioning code.
+class ICRefillVerifierMark: StackObj {
+ public:
+ ICRefillVerifierMark(ICRefillVerifier* verifier);
+ ~ICRefillVerifierMark();
+};
+#else
+class ICRefillVerifier: StackObj {
+ public:
+ ICRefillVerifier() {}
+};
+class ICRefillVerifierMark: StackObj {
+ public:
+ ICRefillVerifierMark(ICRefillVerifier* verifier) {}
+};
+#endif
+
class InlineCacheBuffer: public AllStatic {
private:
// friends
@@ -105,8 +144,6 @@
static CompiledICHolder* _pending_released;
static int _pending_count;
- DEBUG_ONLY(static volatile int _needs_refill;)
-
static StubQueue* buffer() { return _buffer; }
static ICStub* new_ic_stub();
--- a/src/hotspot/share/runtime/sharedRuntime.cpp Fri Dec 07 11:15:18 2018 +0100
+++ b/src/hotspot/share/runtime/sharedRuntime.cpp Fri Dec 07 13:15:35 2018 +0100
@@ -1395,6 +1395,7 @@
// Patching IC caches may fail if we run out if transition stubs.
// We refill the ic stubs then and try again.
for (;;) {
+ ICRefillVerifier ic_refill_verifier;
bool successful = resolve_sub_helper_internal(callee_method, caller_frame, caller_nm,
is_virtual, is_optimized, receiver,
call_info, invoke_code, CHECK_(methodHandle()));
@@ -1603,10 +1604,10 @@
// Potential change to megamorphic
bool successful = inline_cache->set_to_megamorphic(&call_info, bc, needs_ic_stub_refill, CHECK_false);
+ if (needs_ic_stub_refill) {
+ return false;
+ }
if (!successful) {
- if (!needs_ic_stub_refill) {
- return false;
- }
if (!inline_cache->set_to_clean()) {
needs_ic_stub_refill = true;
return false;
@@ -1690,6 +1691,7 @@
CompiledMethod* caller_nm = cb->as_compiled_method();
for (;;) {
+ ICRefillVerifier ic_refill_verifier;
bool needs_ic_stub_refill = false;
bool successful = handle_ic_miss_helper_internal(receiver, caller_nm, caller_frame, callee_method,
bc, call_info, needs_ic_stub_refill, CHECK_(methodHandle()));
@@ -1798,6 +1800,7 @@
// resolve is only done once.
for (;;) {
+ ICRefillVerifier ic_refill_verifier;
if (!clear_ic_at_addr(caller_nm, call_addr, is_static_call)) {
InlineCacheBuffer::refill_ic_stubs();
} else {
--- a/src/hotspot/share/runtime/thread.cpp Fri Dec 07 11:15:18 2018 +0100
+++ b/src/hotspot/share/runtime/thread.cpp Fri Dec 07 13:15:35 2018 +0100
@@ -231,6 +231,7 @@
set_active_handles(NULL);
set_free_handle_block(NULL);
set_last_handle_mark(NULL);
+ DEBUG_ONLY(_missed_ic_stub_refill_mark = NULL);
// This initial value ==> never claimed.
_oops_do_parity = 0;
--- a/src/hotspot/share/runtime/thread.hpp Fri Dec 07 11:15:18 2018 +0100
+++ b/src/hotspot/share/runtime/thread.hpp Fri Dec 07 13:15:35 2018 +0100
@@ -328,6 +328,21 @@
HandleMark* last_handle_mark() const { return _last_handle_mark; }
private:
+#ifdef ASSERT
+ void* _missed_ic_stub_refill_mark;
+
+ public:
+ void* missed_ic_stub_refill_mark() {
+ return _missed_ic_stub_refill_mark;
+ }
+
+ void set_missed_ic_stub_refill_mark(void* mark) {
+ _missed_ic_stub_refill_mark = mark;
+ }
+#endif
+
+ private:
+
// debug support for checking if code does allow safepoints or not
// GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
// mutex, or blocking on an object synchronizer (Java locking).