--- a/src/hotspot/share/code/nmethod.cpp Mon Nov 06 12:17:59 2017 +0100
+++ b/src/hotspot/share/code/nmethod.cpp Mon Nov 06 12:53:55 2017 +0100
@@ -409,6 +409,7 @@
#if INCLUDE_JVMCI
_jvmci_installed_code = NULL;
_speculation_log = NULL;
+ _jvmci_installed_code_triggers_unloading = false;
#endif
}
@@ -461,8 +462,8 @@
AbstractCompiler* compiler,
int comp_level
#if INCLUDE_JVMCI
- , Handle installed_code,
- Handle speculationLog
+ , jweak installed_code,
+ jweak speculationLog
#endif
)
{
@@ -642,8 +643,8 @@
AbstractCompiler* compiler,
int comp_level
#if INCLUDE_JVMCI
- , Handle installed_code,
- Handle speculation_log
+ , jweak installed_code,
+ jweak speculation_log
#endif
)
: CompiledMethod(method, "nmethod", type, nmethod_size, sizeof(nmethod), code_buffer, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps, false),
@@ -671,8 +672,14 @@
set_ctable_begin(header_begin() + _consts_offset);
#if INCLUDE_JVMCI
- _jvmci_installed_code = installed_code();
- _speculation_log = (instanceOop)speculation_log();
+ _jvmci_installed_code = installed_code;
+ _speculation_log = speculation_log;
+ oop obj = JNIHandles::resolve(installed_code);
+ if (obj == NULL || (obj->is_a(HotSpotNmethod::klass()) && HotSpotNmethod::isDefault(obj))) {
+ _jvmci_installed_code_triggers_unloading = false;
+ } else {
+ _jvmci_installed_code_triggers_unloading = true;
+ }
if (compiler->is_jvmci()) {
// JVMCI might not produce any stub sections
@@ -1026,8 +1033,6 @@
" unloadable, Method*(" INTPTR_FORMAT
"), cause(" INTPTR_FORMAT ")",
p2i(this), p2i(_method), p2i(cause));
- if (!Universe::heap()->is_gc_active())
- cause->klass()->print_on(&ls);
}
// Unlink the osr method, so we do not look this up again
if (is_osr_method()) {
@@ -1077,14 +1082,8 @@
#if INCLUDE_JVMCI
// The method can only be unloaded after the pointer to the installed code
// Java wrapper is no longer alive. Here we need to clear out this weak
- // reference to the dead object. Nulling out the reference has to happen
- // after the method is unregistered since the original value may be still
- // tracked by the rset.
+ // reference to the dead object.
maybe_invalidate_installed_code();
- // Clear these out after the nmethod has been unregistered and any
- // updates to the InstalledCode instance have been performed.
- _jvmci_installed_code = NULL;
- _speculation_log = NULL;
#endif
// The Method* is gone at this point
@@ -1246,10 +1245,6 @@
MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
if (nmethod_needs_unregister) {
Universe::heap()->unregister_nmethod(this);
-#ifdef JVMCI
- _jvmci_installed_code = NULL;
- _speculation_log = NULL;
-#endif
}
flush_dependencies(NULL);
}
@@ -1314,6 +1309,11 @@
CodeCache::drop_scavenge_root_nmethod(this);
}
+#if INCLUDE_JVMCI
+ assert(_jvmci_installed_code == NULL, "should have been nulled out when transitioned to zombie");
+ assert(_speculation_log == NULL, "should have been nulled out when transitioned to zombie");
+#endif
+
CodeBlob::flush();
CodeCache::free(this);
}
@@ -1500,29 +1500,18 @@
#if INCLUDE_JVMCI
bool nmethod::do_unloading_jvmci(BoolObjectClosure* is_alive, bool unloading_occurred) {
- bool is_unloaded = false;
- // Follow JVMCI method
- BarrierSet* bs = Universe::heap()->barrier_set();
if (_jvmci_installed_code != NULL) {
- if (_jvmci_installed_code->is_a(HotSpotNmethod::klass()) && HotSpotNmethod::isDefault(_jvmci_installed_code)) {
- if (!is_alive->do_object_b(_jvmci_installed_code)) {
+ if (JNIHandles::is_global_weak_cleared(_jvmci_installed_code)) {
+ if (_jvmci_installed_code_triggers_unloading) {
+ // jweak reference processing has already cleared the referent
+ make_unloaded(is_alive, NULL);
+ return true;
+ } else {
clear_jvmci_installed_code();
}
- } else {
- if (can_unload(is_alive, (oop*)&_jvmci_installed_code, unloading_occurred)) {
- return true;
- }
}
}
-
- if (_speculation_log != NULL) {
- if (!is_alive->do_object_b(_speculation_log)) {
- bs->write_ref_nmethod_pre(&_speculation_log, this);
- _speculation_log = NULL;
- bs->write_ref_nmethod_post(&_speculation_log, this);
- }
- }
- return is_unloaded;
+ return false;
}
#endif
@@ -1594,15 +1583,6 @@
// (See comment above.)
}
-#if INCLUDE_JVMCI
- if (_jvmci_installed_code != NULL) {
- f->do_oop((oop*) &_jvmci_installed_code);
- }
- if (_speculation_log != NULL) {
- f->do_oop((oop*) &_speculation_log);
- }
-#endif
-
RelocIterator iter(this, low_boundary);
while (iter.next()) {
@@ -2860,43 +2840,49 @@
#if INCLUDE_JVMCI
void nmethod::clear_jvmci_installed_code() {
- // write_ref_method_pre/post can only be safely called at a
- // safepoint or while holding the CodeCache_lock
- assert(CodeCache_lock->is_locked() ||
- SafepointSynchronize::is_at_safepoint(), "should be performed under a lock for consistency");
+ assert_locked_or_safepoint(Patching_lock);
if (_jvmci_installed_code != NULL) {
- // This must be done carefully to maintain nmethod remembered sets properly
- BarrierSet* bs = Universe::heap()->barrier_set();
- bs->write_ref_nmethod_pre(&_jvmci_installed_code, this);
+ JNIHandles::destroy_weak_global(_jvmci_installed_code);
_jvmci_installed_code = NULL;
- bs->write_ref_nmethod_post(&_jvmci_installed_code, this);
+ }
+}
+
+void nmethod::clear_speculation_log() {
+ assert_locked_or_safepoint(Patching_lock);
+ if (_speculation_log != NULL) {
+ JNIHandles::destroy_weak_global(_speculation_log);
+ _speculation_log = NULL;
}
}
void nmethod::maybe_invalidate_installed_code() {
assert(Patching_lock->is_locked() ||
SafepointSynchronize::is_at_safepoint(), "should be performed under a lock for consistency");
- oop installed_code = jvmci_installed_code();
+ oop installed_code = JNIHandles::resolve(_jvmci_installed_code);
if (installed_code != NULL) {
+ // Update the values in the InstalledCode instance if it still refers to this nmethod
nmethod* nm = (nmethod*)InstalledCode::address(installed_code);
- if (nm == NULL || nm != this) {
- // The link has been broken or the InstalledCode instance is
- // associated with another nmethod so do nothing.
- return;
+ if (nm == this) {
+ if (!is_alive()) {
+ // Break the link between nmethod and InstalledCode such that the nmethod
+ // can subsequently be flushed safely. The link must be maintained while
+ // the method could have live activations since invalidateInstalledCode
+ // might want to invalidate all existing activations.
+ InstalledCode::set_address(installed_code, 0);
+ InstalledCode::set_entryPoint(installed_code, 0);
+ } else if (is_not_entrant()) {
+ // Remove the entry point so any invocation will fail but keep
+ // the address link around that so that existing activations can
+ // be invalidated.
+ InstalledCode::set_entryPoint(installed_code, 0);
+ }
}
- if (!is_alive()) {
- // Break the link between nmethod and InstalledCode such that the nmethod
- // can subsequently be flushed safely. The link must be maintained while
- // the method could have live activations since invalidateInstalledCode
- // might want to invalidate all existing activations.
- InstalledCode::set_address(installed_code, 0);
- InstalledCode::set_entryPoint(installed_code, 0);
- } else if (is_not_entrant()) {
- // Remove the entry point so any invocation will fail but keep
- // the address link around that so that existing activations can
- // be invalidated.
- InstalledCode::set_entryPoint(installed_code, 0);
- }
+ }
+ if (!is_alive()) {
+ // Clear these out after the nmethod has been unregistered and any
+ // updates to the InstalledCode instance have been performed.
+ clear_jvmci_installed_code();
+ clear_speculation_log();
}
}
@@ -2916,45 +2902,49 @@
{
MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
// This relationship can only be checked safely under a lock
- assert(nm == NULL || !nm->is_alive() || nm->jvmci_installed_code() == installedCode(), "sanity check");
+ assert(!nm->is_alive() || nm->jvmci_installed_code() == installedCode(), "sanity check");
}
#endif
if (nm->is_alive()) {
- // The nmethod state machinery maintains the link between the
- // HotSpotInstalledCode and nmethod* so as long as the nmethod appears to be
- // alive assume there is work to do and deoptimize the nmethod.
+ // Invalidating the InstalledCode means we want the nmethod
+ // to be deoptimized.
nm->mark_for_deoptimization();
VM_Deoptimize op;
VMThread::execute(&op);
}
+ // Multiple threads could reach this point so we now need to
+ // lock and re-check the link to the nmethod so that only one
+ // thread clears it.
MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
- // Check that it's still associated with the same nmethod and break
- // the link if it is.
if (InstalledCode::address(installedCode) == nativeMethod) {
- InstalledCode::set_address(installedCode, 0);
+ InstalledCode::set_address(installedCode, 0);
}
}
+oop nmethod::jvmci_installed_code() {
+ return JNIHandles::resolve(_jvmci_installed_code);
+}
+
+oop nmethod::speculation_log() {
+ return JNIHandles::resolve(_speculation_log);
+}
+
char* nmethod::jvmci_installed_code_name(char* buf, size_t buflen) {
if (!this->is_compiled_by_jvmci()) {
return NULL;
}
- oop installedCode = this->jvmci_installed_code();
- if (installedCode != NULL) {
- oop installedCodeName = NULL;
- if (installedCode->is_a(InstalledCode::klass())) {
- installedCodeName = InstalledCode::name(installedCode);
+ oop installed_code = JNIHandles::resolve(_jvmci_installed_code);
+ if (installed_code != NULL) {
+ oop installed_code_name = NULL;
+ if (installed_code->is_a(InstalledCode::klass())) {
+ installed_code_name = InstalledCode::name(installed_code);
}
- if (installedCodeName != NULL) {
- return java_lang_String::as_utf8_string(installedCodeName, buf, (int)buflen);
- } else {
- jio_snprintf(buf, buflen, "null");
- return buf;
+ if (installed_code_name != NULL) {
+ return java_lang_String::as_utf8_string(installed_code_name, buf, (int)buflen);
}
}
- jio_snprintf(buf, buflen, "noInstalledCode");
- return buf;
+ return NULL;
}
#endif