8213486: SIGSEGV in CompiledMethod::cleanup_inline_caches_impl with AOT

Reviewed-by: kvn, dlong

src/hotspot/share/aot/aotCompiledMethod.hpp

@@ -176,6 +176,8 @@ private:
   virtual bool is_alive() const { return _is_alive(); }
   virtual bool is_in_use() const { return state() == in_use; }
 
+  virtual bool is_unloading() { return false; }
+
   address exception_begin() const { return (address) _code + _meta->exception_handler_offset(); }
 
   virtual const char* name() const { return _name; }

src/hotspot/share/code/compiledMethod.cpp

@@ -44,11 +44,9 @@ CompiledMethod::CompiledMethod(Method* method, const char* name, CompilerType ty
                                bool caller_must_gc_arguments)
   : CodeBlob(name, type, layout, frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments),
     _mark_for_deoptimization_status(not_marked),
-    _is_unloading_state(0),
     _method(method)
 {
   init_defaults();
-  clear_unloading_state();
 }
 
 CompiledMethod::CompiledMethod(Method* method, const char* name, CompilerType type, int size,
@@ -57,11 +55,9 @@ CompiledMethod::CompiledMethod(Method* method, const char* name, CompilerType ty
   : CodeBlob(name, type, CodeBlobLayout((address) this, size, header_size, cb), cb,
              frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments),
     _mark_for_deoptimization_status(not_marked),
-    _is_unloading_state(0),
     _method(method)
 {
   init_defaults();
-  clear_unloading_state();
 }
 
 void CompiledMethod::init_defaults() {
@@ -546,74 +542,6 @@ void CompiledMethod::unload_nmethod_caches(bool unloading_occurred) {
   DEBUG_ONLY(metadata_do(check_class));
 }
 
-// The _is_unloading_state encodes a tuple comprising the unloading cycle
-// and the result of IsUnloadingBehaviour::is_unloading() fpr that cycle.
-// This is the bit layout of the _is_unloading_state byte: 00000CCU
-// CC refers to the cycle, which has 2 bits, and U refers to the result of
-// IsUnloadingBehaviour::is_unloading() for that unloading cycle.
-
-class IsUnloadingState: public AllStatic {
-  static const uint8_t _is_unloading_mask = 1;
-  static const uint8_t _is_unloading_shift = 0;
-  static const uint8_t _unloading_cycle_mask = 6;
-  static const uint8_t _unloading_cycle_shift = 1;
-
-  static uint8_t set_is_unloading(uint8_t state, bool value) {
-    state &= ~_is_unloading_mask;
-    if (value) {
-      state |= 1 << _is_unloading_shift;
-    }
-    assert(is_unloading(state) == value, "unexpected unloading cycle overflow");
-    return state;
-  }
-
-  static uint8_t set_unloading_cycle(uint8_t state, uint8_t value) {
-    state &= ~_unloading_cycle_mask;
-    state |= value << _unloading_cycle_shift;
-    assert(unloading_cycle(state) == value, "unexpected unloading cycle overflow");
-    return state;
-  }
-
-public:
-  static bool is_unloading(uint8_t state) { return (state & _is_unloading_mask) >> _is_unloading_shift == 1; }
-  static uint8_t unloading_cycle(uint8_t state) { return (state & _unloading_cycle_mask) >> _unloading_cycle_shift; }
-
-  static uint8_t create(bool is_unloading, uint8_t unloading_cycle) {
-    uint8_t state = 0;
-    state = set_is_unloading(state, is_unloading);
-    state = set_unloading_cycle(state, unloading_cycle);
-    return state;
-  }
-};
-
-bool CompiledMethod::is_unloading() {
-  uint8_t state = RawAccess<MO_RELAXED>::load(&_is_unloading_state);
-  bool state_is_unloading = IsUnloadingState::is_unloading(state);
-  uint8_t state_unloading_cycle = IsUnloadingState::unloading_cycle(state);
-  if (state_is_unloading) {
-    return true;
-  }
-  if (state_unloading_cycle == CodeCache::unloading_cycle()) {
-    return false;
-  }
-
-  // The IsUnloadingBehaviour is responsible for checking if there are any dead
-  // oops in the CompiledMethod, by calling oops_do on it.
-  state_unloading_cycle = CodeCache::unloading_cycle();
-  state_is_unloading = IsUnloadingBehaviour::current()->is_unloading(this);
-
-  state = IsUnloadingState::create(state_is_unloading, state_unloading_cycle);
-
-  RawAccess<MO_RELAXED>::store(&_is_unloading_state, state);
-
-  return state_is_unloading;
-}
-
-void CompiledMethod::clear_unloading_state() {
-  uint8_t state = IsUnloadingState::create(false, CodeCache::unloading_cycle());
-  RawAccess<MO_RELAXED>::store(&_is_unloading_state, state);
-}
-
 // Called to clean up after class unloading for live nmethods and from the sweeper
 // for all methods.
 void CompiledMethod::cleanup_inline_caches_impl(bool unloading_occurred, bool clean_all) {

src/hotspot/share/code/compiledMethod.hpp

@@ -151,8 +151,6 @@ protected:
   bool _is_far_code; // Code is far from CodeCache.
                      // Have to use far call instructions to call it from code in CodeCache.
 
-  volatile uint8_t _is_unloading_state;      // Local state used to keep track of whether unloading is happening or not
-
   // set during construction
   unsigned int _has_unsafe_access:1;         // May fault due to unsafe access.
   unsigned int _has_method_handle_invokes:1; // Has this method MethodHandle invokes?
@@ -390,10 +388,9 @@ public:
   // GC unloading support
   // Cleans unloaded klasses and unloaded nmethods in inline caches
 
-  bool is_unloading();
+  virtual bool is_unloading() = 0;
 
   void unload_nmethod_caches(bool class_unloading_occurred);
-  void clear_unloading_state();
   virtual void do_unloading(bool unloading_occurred) { }
 
 private:

src/hotspot/share/code/nmethod.cpp

@@ -565,6 +565,7 @@ nmethod::nmethod(
   ByteSize basic_lock_sp_offset,
   OopMapSet* oop_maps )
   : CompiledMethod(method, "native nmethod", type, nmethod_size, sizeof(nmethod), code_buffer, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps, false),
+  _is_unloading_state(0),
   _native_receiver_sp_offset(basic_lock_owner_sp_offset),
   _native_basic_lock_sp_offset(basic_lock_sp_offset)
 {
@@ -609,6 +610,7 @@ nmethod::nmethod(
     code_buffer->copy_code_and_locs_to(this);
     code_buffer->copy_values_to(this);
 
+    clear_unloading_state();
     if (ScavengeRootsInCode) {
       Universe::heap()->register_nmethod(this);
     }
@@ -672,6 +674,7 @@ nmethod::nmethod(
 #endif
   )
   : CompiledMethod(method, "nmethod", type, nmethod_size, sizeof(nmethod), code_buffer, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps, false),
+  _is_unloading_state(0),
   _native_receiver_sp_offset(in_ByteSize(-1)),
   _native_basic_lock_sp_offset(in_ByteSize(-1))
 {
@@ -1505,6 +1508,74 @@ void nmethod::metadata_do(void f(Metadata*)) {
   if (_method != NULL) f(_method);
 }
 
+// The _is_unloading_state encodes a tuple comprising the unloading cycle
+// and the result of IsUnloadingBehaviour::is_unloading() fpr that cycle.
+// This is the bit layout of the _is_unloading_state byte: 00000CCU
+// CC refers to the cycle, which has 2 bits, and U refers to the result of
+// IsUnloadingBehaviour::is_unloading() for that unloading cycle.
+
+class IsUnloadingState: public AllStatic {
+  static const uint8_t _is_unloading_mask = 1;
+  static const uint8_t _is_unloading_shift = 0;
+  static const uint8_t _unloading_cycle_mask = 6;
+  static const uint8_t _unloading_cycle_shift = 1;
+
+  static uint8_t set_is_unloading(uint8_t state, bool value) {
+    state &= ~_is_unloading_mask;
+    if (value) {
+      state |= 1 << _is_unloading_shift;
+    }
+    assert(is_unloading(state) == value, "unexpected unloading cycle overflow");
+    return state;
+  }
+
+  static uint8_t set_unloading_cycle(uint8_t state, uint8_t value) {
+    state &= ~_unloading_cycle_mask;
+    state |= value << _unloading_cycle_shift;
+    assert(unloading_cycle(state) == value, "unexpected unloading cycle overflow");
+    return state;
+  }
+
+public:
+  static bool is_unloading(uint8_t state) { return (state & _is_unloading_mask) >> _is_unloading_shift == 1; }
+  static uint8_t unloading_cycle(uint8_t state) { return (state & _unloading_cycle_mask) >> _unloading_cycle_shift; }
+
+  static uint8_t create(bool is_unloading, uint8_t unloading_cycle) {
+    uint8_t state = 0;
+    state = set_is_unloading(state, is_unloading);
+    state = set_unloading_cycle(state, unloading_cycle);
+    return state;
+  }
+};
+
+bool nmethod::is_unloading() {
+  uint8_t state = RawAccess<MO_RELAXED>::load(&_is_unloading_state);
+  bool state_is_unloading = IsUnloadingState::is_unloading(state);
+  uint8_t state_unloading_cycle = IsUnloadingState::unloading_cycle(state);
+  if (state_is_unloading) {
+    return true;
+  }
+  if (state_unloading_cycle == CodeCache::unloading_cycle()) {
+    return false;
+  }
+
+  // The IsUnloadingBehaviour is responsible for checking if there are any dead
+  // oops in the CompiledMethod, by calling oops_do on it.
+  state_unloading_cycle = CodeCache::unloading_cycle();
+  state_is_unloading = IsUnloadingBehaviour::current()->is_unloading(this);
+
+  state = IsUnloadingState::create(state_is_unloading, state_unloading_cycle);
+
+  RawAccess<MO_RELAXED>::store(&_is_unloading_state, state);
+
+  return state_is_unloading;
+}
+
+void nmethod::clear_unloading_state() {
+  uint8_t state = IsUnloadingState::create(false, CodeCache::unloading_cycle());
+  RawAccess<MO_RELAXED>::store(&_is_unloading_state, state);
+}
+
 
 // This is called at the end of the strong tracing/marking phase of a
 // GC to unload an nmethod if it contains otherwise unreachable

src/hotspot/share/code/nmethod.hpp

@@ -158,6 +158,9 @@ class nmethod : public CompiledMethod {
   // counter is decreased (by 1) while sweeping.
   int _hotness_counter;
 
+  // Local state used to keep track of whether unloading is happening or not
+  volatile uint8_t _is_unloading_state;
+
   // These are used for compiled synchronized native methods to
   // locate the owner and stack slot for the BasicLock so that we can
   // properly revoke the bias of the owner if necessary. They are
@@ -323,6 +326,8 @@ class nmethod : public CompiledMethod {
   bool  is_zombie() const                         { return _state == zombie; }
   bool  is_unloaded() const                       { return _state == unloaded; }
 
+  void clear_unloading_state();
+  virtual bool is_unloading();
   virtual void do_unloading(bool unloading_occurred);
 
 #if INCLUDE_RTM_OPT