8031752: Failed speculative optimizations should be reattempted when root of...

8031752: Failed speculative optimizations should be reattempted when root of compilation is different
Summary: support for speculative traps that keep track of the root of the compilation in which a trap occurs.
Reviewed-by: kvn, twisti

src/share/vm/ci/ciClassList.hpp

@@ -103,6 +103,7 @@ friend class ciMethodHandle;           \
 friend class ciMethodType;             \
 friend class ciReceiverTypeData;       \
 friend class ciTypeEntries;            \
+friend class ciSpeculativeTrapData;    \
 friend class ciSymbol;                 \
 friend class ciArray;                  \
 friend class ciObjArray;               \

src/share/vm/ci/ciMethodData.cpp

@@ -78,6 +78,35 @@ ciMethodData::ciMethodData() : ciMetadata(NULL) {
   _parameters = NULL;
 }
 
+void ciMethodData::load_extra_data() {
+  MethodData* mdo = get_MethodData();
+
+  // speculative trap entries also hold a pointer to a Method so need to be translated
+  DataLayout* dp_src  = mdo->extra_data_base();
+  DataLayout* end_src = mdo->extra_data_limit();
+  DataLayout* dp_dst  = extra_data_base();
+  for (;; dp_src = MethodData::next_extra(dp_src), dp_dst = MethodData::next_extra(dp_dst)) {
+    assert(dp_src < end_src, "moved past end of extra data");
+    assert(dp_src->tag() == dp_dst->tag(), err_msg("should be same tags %d != %d", dp_src->tag(), dp_dst->tag()));
+    switch(dp_src->tag()) {
+    case DataLayout::speculative_trap_data_tag: {
+      ciSpeculativeTrapData* data_dst = new ciSpeculativeTrapData(dp_dst);
+      SpeculativeTrapData* data_src = new SpeculativeTrapData(dp_src);
+      data_dst->translate_from(data_src);
+      break;
+    }
+    case DataLayout::bit_data_tag:
+      break;
+    case DataLayout::no_tag:
+    case DataLayout::arg_info_data_tag:
+      // An empty slot or ArgInfoData entry marks the end of the trap data
+      return;
+    default:
+      fatal(err_msg("bad tag = %d", dp_src->tag()));
+    }
+  }
+}
+
 void ciMethodData::load_data() {
   MethodData* mdo = get_MethodData();
   if (mdo == NULL) {
@@ -116,6 +145,8 @@ void ciMethodData::load_data() {
     parameters->translate_from(mdo->parameters_type_data());
   }
 
+  load_extra_data();
+
   // Note:  Extra data are all BitData, and do not need translation.
   _current_mileage = MethodData::mileage_of(mdo->method());
   _invocation_counter = mdo->invocation_count();
@@ -156,6 +187,12 @@ void ciReturnTypeEntry::translate_type_data_from(const ReturnTypeEntry* ret) {
   set_type(translate_klass(k));
 }
 
+void ciSpeculativeTrapData::translate_from(const ProfileData* data) {
+  Method* m = data->as_SpeculativeTrapData()->method();
+  ciMethod* ci_m = CURRENT_ENV->get_method(m);
+  set_method(ci_m);
+}
+
 // Get the data at an arbitrary (sort of) data index.
 ciProfileData* ciMethodData::data_at(int data_index) {
   if (out_of_bounds(data_index)) {
@@ -203,33 +240,65 @@ ciProfileData* ciMethodData::next_data(ciProfileData* current) {
   return next;
 }
 
-// Translate a bci to its corresponding data, or NULL.
-ciProfileData* ciMethodData::bci_to_data(int bci) {
-  ciProfileData* data = data_before(bci);
-  for ( ; is_valid(data); data = next_data(data)) {
-    if (data->bci() == bci) {
-      set_hint_di(dp_to_di(data->dp()));
-      return data;
-    } else if (data->bci() > bci) {
-      break;
-    }
-  }
+ciProfileData* ciMethodData::bci_to_extra_data(int bci, ciMethod* m, bool& two_free_slots) {
   // bci_to_extra_data(bci) ...
   DataLayout* dp  = data_layout_at(data_size());
   DataLayout* end = data_layout_at(data_size() + extra_data_size());
-  for (; dp < end; dp = MethodData::next_extra(dp)) {
-    if (dp->tag() == DataLayout::no_tag) {
+  two_free_slots = false;
+  for (;dp < end; dp = MethodData::next_extra(dp)) {
+    switch(dp->tag()) {
+    case DataLayout::no_tag:
       _saw_free_extra_data = true;  // observed an empty slot (common case)
+      two_free_slots = (MethodData::next_extra(dp)->tag() == DataLayout::no_tag);
       return NULL;
+    case DataLayout::arg_info_data_tag:
+      return NULL; // ArgInfoData is at the end of extra data section.
+    case DataLayout::bit_data_tag:
+      if (m == NULL && dp->bci() == bci) {
+        return new ciBitData(dp);
+      }
+      break;
+    case DataLayout::speculative_trap_data_tag: {
+      ciSpeculativeTrapData* data = new ciSpeculativeTrapData(dp);
+      // data->method() might be null if the MDO is snapshotted
+      // concurrently with a trap
+      if (m != NULL && data->method() == m && dp->bci() == bci) {
+        return data;
+      }
+      break;
     }
-    if (dp->tag() == DataLayout::arg_info_data_tag) {
-      break; // ArgInfoData is at the end of extra data section.
+    default:
+      fatal(err_msg("bad tag = %d", dp->tag()));
     }
-    if (dp->bci() == bci) {
-      assert(dp->tag() == DataLayout::bit_data_tag, "sane");
-      return new ciBitData(dp);
+  }
+  return NULL;
+}
+
+// Translate a bci to its corresponding data, or NULL.
+ciProfileData* ciMethodData::bci_to_data(int bci, ciMethod* m) {
+  // If m is not NULL we look for a SpeculativeTrapData entry
+  if (m == NULL) {
+    ciProfileData* data = data_before(bci);
+    for ( ; is_valid(data); data = next_data(data)) {
+      if (data->bci() == bci) {
+        set_hint_di(dp_to_di(data->dp()));
+        return data;
+      } else if (data->bci() > bci) {
+        break;
+      }
     }
   }
+  bool two_free_slots = false;
+  ciProfileData* result = bci_to_extra_data(bci, m, two_free_slots);
+  if (result != NULL) {
+    return result;
+  }
+  if (m != NULL && !two_free_slots) {
+    // We were looking for a SpeculativeTrapData entry we didn't
+    // find. Room is not available for more SpeculativeTrapData
+    // entries, look in the non SpeculativeTrapData entries.
+    return bci_to_data(bci, NULL);
+  }
   return NULL;
 }
 
@@ -525,18 +594,25 @@ void ciMethodData::print_data_on(outputStream* st) {
   st->print_cr("--- Extra data:");
   DataLayout* dp  = data_layout_at(data_size());
   DataLayout* end = data_layout_at(data_size() + extra_data_size());
-  for (; dp < end; dp = MethodData::next_extra(dp)) {
-    if (dp->tag() == DataLayout::no_tag)  continue;
-    if (dp->tag() == DataLayout::bit_data_tag) {
+  for (;; dp = MethodData::next_extra(dp)) {
+    assert(dp < end, "moved past end of extra data");
+    switch (dp->tag()) {
+    case DataLayout::no_tag:
+      continue;
+    case DataLayout::bit_data_tag:
       data = new BitData(dp);
-    } else {
-      assert(dp->tag() == DataLayout::arg_info_data_tag, "must be BitData or ArgInfo");
+      break;
+    case DataLayout::arg_info_data_tag:
       data = new ciArgInfoData(dp);
       dp = end; // ArgInfoData is at the end of extra data section.
+      break;
+    default:
+      fatal(err_msg("unexpected tag %d", dp->tag()));
     }
     st->print("%d", dp_to_di(data->dp()));
     st->fill_to(6);
     data->print_data_on(st);
+    if (dp >= end) return;
   }
 }
 
@@ -569,8 +645,8 @@ void ciReturnTypeEntry::print_data_on(outputStream* st) const {
   st->cr();
 }
 
-void ciCallTypeData::print_data_on(outputStream* st) const {
-  print_shared(st, "ciCallTypeData");
+void ciCallTypeData::print_data_on(outputStream* st, const char* extra) const {
+  print_shared(st, "ciCallTypeData", extra);
   if (has_arguments()) {
     tab(st, true);
     st->print("argument types");
@@ -599,18 +675,18 @@ void ciReceiverTypeData::print_receiver_data_on(outputStream* st) const {
   }
 }
 
-void ciReceiverTypeData::print_data_on(outputStream* st) const {
-  print_shared(st, "ciReceiverTypeData");
+void ciReceiverTypeData::print_data_on(outputStream* st, const char* extra) const {
+  print_shared(st, "ciReceiverTypeData", extra);
   print_receiver_data_on(st);
 }
 
-void ciVirtualCallData::print_data_on(outputStream* st) const {
-  print_shared(st, "ciVirtualCallData");
+void ciVirtualCallData::print_data_on(outputStream* st, const char* extra) const {
+  print_shared(st, "ciVirtualCallData", extra);
   rtd_super()->print_receiver_data_on(st);
 }
 
-void ciVirtualCallTypeData::print_data_on(outputStream* st) const {
-  print_shared(st, "ciVirtualCallTypeData");
+void ciVirtualCallTypeData::print_data_on(outputStream* st, const char* extra) const {
+  print_shared(st, "ciVirtualCallTypeData", extra);
   rtd_super()->print_receiver_data_on(st);
   if (has_arguments()) {
     tab(st, true);
@@ -624,8 +700,15 @@ void ciVirtualCallTypeData::print_data_on(outputStream* st) const {
   }
 }
 
-void ciParametersTypeData::print_data_on(outputStream* st) const {
-  st->print_cr("Parametertypes");
+void ciParametersTypeData::print_data_on(outputStream* st, const char* extra) const {
+  st->print_cr("ciParametersTypeData");
   parameters()->print_data_on(st);
 }
+
+void ciSpeculativeTrapData::print_data_on(outputStream* st, const char* extra) const {
+  st->print_cr("ciSpeculativeTrapData");
+  tab(st);
+  method()->print_short_name(st);
+  st->cr();
+}
 #endif

src/share/vm/ci/ciMethodData.hpp

@@ -31,6 +31,7 @@
 #include "ci/ciUtilities.hpp"
 #include "oops/methodData.hpp"
 #include "oops/oop.inline.hpp"
+#include "runtime/deoptimization.hpp"
 
 class ciBitData;
 class ciCounterData;
@@ -44,6 +45,7 @@ class ciArgInfoData;
 class ciCallTypeData;
 class ciVirtualCallTypeData;
 class ciParametersTypeData;
+class ciSpeculativeTrapData;;
 
 typedef ProfileData ciProfileData;
 
@@ -173,7 +175,7 @@ public:
   }
 
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra) const;
 #endif
 };
 
@@ -200,7 +202,7 @@ public:
   }
   void translate_receiver_data_from(const ProfileData* data);
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra) const;
   void print_receiver_data_on(outputStream* st) const;
 #endif
 };
@@ -225,7 +227,7 @@ public:
     rtd_super()->translate_receiver_data_from(data);
   }
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra) const;
 #endif
 };
 
@@ -287,7 +289,7 @@ public:
   }
 
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra) const;
 #endif
 };
 
@@ -336,7 +338,26 @@ public:
   }
 
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra) const;
+#endif
+};
+
+class ciSpeculativeTrapData : public SpeculativeTrapData {
+public:
+  ciSpeculativeTrapData(DataLayout* layout) : SpeculativeTrapData(layout) {}
+
+  virtual void translate_from(const ProfileData* data);
+
+  ciMethod* method() const {
+    return (ciMethod*)intptr_at(method_offset);
+  }
+
+  void set_method(ciMethod* m) {
+    set_intptr_at(method_offset, (intptr_t)m);
+  }
+
+#ifndef PRODUCT
+  void print_data_on(outputStream* st, const char* extra) const;
 #endif
 };
 
@@ -436,6 +457,16 @@ private:
 
   ciArgInfoData *arg_info() const;
 
+  address data_base() const {
+    return (address) _data;
+  }
+  DataLayout* limit_data_position() const {
+    return (DataLayout*)((address)data_base() + _data_size);
+  }
+
+  void load_extra_data();
+  ciProfileData* bci_to_extra_data(int bci, ciMethod* m, bool& two_free_slots);
+
 public:
   bool is_method_data() const { return true; }
 
@@ -475,9 +506,11 @@ public:
   ciProfileData* next_data(ciProfileData* current);
   bool is_valid(ciProfileData* current) { return current != NULL; }
 
-  // Get the data at an arbitrary bci, or NULL if there is none.
-  ciProfileData* bci_to_data(int bci);
-  ciProfileData* bci_to_extra_data(int bci, bool create_if_missing);
+  DataLayout* extra_data_base() const { return limit_data_position(); }
+
+  // Get the data at an arbitrary bci, or NULL if there is none. If m
+  // is not NULL look for a SpeculativeTrapData if any first.
+  ciProfileData* bci_to_data(int bci, ciMethod* m = NULL);
 
   uint overflow_trap_count() const {
     return _orig.overflow_trap_count();
@@ -496,12 +529,13 @@ public:
 
   // Helpful query functions that decode trap_state.
   int has_trap_at(ciProfileData* data, int reason);
-  int has_trap_at(int bci, int reason) {
-    return has_trap_at(bci_to_data(bci), reason);
+  int has_trap_at(int bci, ciMethod* m, int reason) {
+    assert((m != NULL) == Deoptimization::reason_is_speculate(reason), "inconsistent method/reason");
+    return has_trap_at(bci_to_data(bci, m), reason);
   }
   int trap_recompiled_at(ciProfileData* data);
-  int trap_recompiled_at(int bci) {
-    return trap_recompiled_at(bci_to_data(bci));
+  int trap_recompiled_at(int bci, ciMethod* m) {
+    return trap_recompiled_at(bci_to_data(bci, m));
   }
 
   void clear_escape_info();

src/share/vm/interpreter/bytecodeTracer.cpp

@@ -596,7 +596,7 @@ void BytecodePrinter::bytecode_epilog(int bci, outputStream* st) {
     if (data != NULL) {
       st->print("  %d", mdo->dp_to_di(data->dp()));
       st->fill_to(6);
-      data->print_data_on(st);
+      data->print_data_on(st, mdo);
     }
   }
 }

src/share/vm/oops/instanceKlass.cpp

@@ -2234,15 +2234,7 @@ void InstanceKlass::clean_method_data(BoolObjectClosure* is_alive) {
   for (int m = 0; m < methods()->length(); m++) {
     MethodData* mdo = methods()->at(m)->method_data();
     if (mdo != NULL) {
-      for (ProfileData* data = mdo->first_data();
-           mdo->is_valid(data);
-           data = mdo->next_data(data)) {
-        data->clean_weak_klass_links(is_alive);
-      }
-      ParametersTypeData* parameters = mdo->parameters_type_data();
-      if (parameters != NULL) {
-        parameters->clean_weak_klass_links(is_alive);
-      }
+      mdo->clean_method_data(is_alive);
     }
   }
 }

src/share/vm/oops/instanceKlass.hpp

@@ -306,7 +306,7 @@ class InstanceKlass: public Klass {
   //   three cases:
   //     NULL: no implementor.
   //     A Klass* that's not itself: one implementor.
-  //     Itsef: more than one implementors.
+  //     Itself: more than one implementors.
   // embedded host klass follows here
   //   The embedded host klass only exists in an anonymous class for
   //   dynamic language support (JSR 292 enabled). The host class grants

src/share/vm/oops/methodData.hpp

@@ -120,7 +120,8 @@ public:
     arg_info_data_tag,
     call_type_data_tag,
     virtual_call_type_data_tag,
-    parameters_type_data_tag
+    parameters_type_data_tag,
+    speculative_trap_data_tag
   };
 
   enum {
@@ -189,8 +190,11 @@ public:
   void set_header(intptr_t value) {
     _header._bits = value;
   }
-  void release_set_header(intptr_t value) {
-    OrderAccess::release_store_ptr(&_header._bits, value);
+  bool atomic_set_header(intptr_t value) {
+    if (Atomic::cmpxchg_ptr(value, (volatile intptr_t*)&_header._bits, 0) == 0) {
+      return true;
+    }
+    return false;
   }
   intptr_t header() {
     return _header._bits;
@@ -266,6 +270,7 @@ class   ArrayData;
 class     MultiBranchData;
 class     ArgInfoData;
 class     ParametersTypeData;
+class   SpeculativeTrapData;
 
 // ProfileData
 //
@@ -286,6 +291,8 @@ private:
   // This is a pointer to a section of profiling data.
   DataLayout* _data;
 
+  char* print_data_on_helper(const MethodData* md) const;
+
 protected:
   DataLayout* data() { return _data; }
   const DataLayout* data() const { return _data; }
@@ -400,6 +407,7 @@ public:
   virtual bool is_CallTypeData()    const { return false; }
   virtual bool is_VirtualCallTypeData()const { return false; }
   virtual bool is_ParametersTypeData() const { return false; }
+  virtual bool is_SpeculativeTrapData()const { return false; }
 
 
   BitData* as_BitData() const {
@@ -454,6 +462,10 @@ public:
     assert(is_ParametersTypeData(), "wrong type");
     return is_ParametersTypeData() ? (ParametersTypeData*)this : NULL;
   }
+  SpeculativeTrapData* as_SpeculativeTrapData() const {
+    assert(is_SpeculativeTrapData(), "wrong type");
+    return is_SpeculativeTrapData() ? (SpeculativeTrapData*)this : NULL;
+  }
 
 
   // Subclass specific initialization
@@ -469,12 +481,14 @@ public:
   // translation here, and the required translators are in the ci subclasses.
   virtual void translate_from(const ProfileData* data) {}
 
-  virtual void print_data_on(outputStream* st) const {
+  virtual void print_data_on(outputStream* st, const char* extra = NULL) const {
     ShouldNotReachHere();
   }
 
+  void print_data_on(outputStream* st, const MethodData* md) const;
+
 #ifndef PRODUCT
-  void print_shared(outputStream* st, const char* name) const;
+  void print_shared(outputStream* st, const char* name, const char* extra) const;
   void tab(outputStream* st, bool first = false) const;
 #endif
 };
@@ -522,7 +536,7 @@ public:
   }
 
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 };
 
@@ -566,7 +580,7 @@ public:
   }
 
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 };
 
@@ -639,7 +653,7 @@ public:
   void post_initialize(BytecodeStream* stream, MethodData* mdo);
 
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 };
 
@@ -1050,7 +1064,7 @@ public:
   }
 
 #ifndef PRODUCT
-  virtual void print_data_on(outputStream* st) const;
+  virtual void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 };
 
@@ -1158,7 +1172,7 @@ public:
 
 #ifndef PRODUCT
   void print_receiver_data_on(outputStream* st) const;
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 };
 
@@ -1191,7 +1205,7 @@ public:
   }
 
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 };
 
@@ -1317,7 +1331,7 @@ public:
   }
 
 #ifndef PRODUCT
-  virtual void print_data_on(outputStream* st) const;
+  virtual void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 };
 
@@ -1416,7 +1430,7 @@ public:
   void post_initialize(BytecodeStream* stream, MethodData* mdo);
 
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 };
 
@@ -1480,7 +1494,7 @@ public:
   void post_initialize(BytecodeStream* stream, MethodData* mdo);
 
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 };
 
@@ -1637,7 +1651,7 @@ public:
   void post_initialize(BytecodeStream* stream, MethodData* mdo);
 
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 };
 
@@ -1664,7 +1678,7 @@ public:
   }
 
 #ifndef PRODUCT
-  void print_data_on(outputStream* st) const;
+  void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 };
 
@@ -1725,7 +1739,7 @@ public:
   }
 
 #ifndef PRODUCT
-  virtual void print_data_on(outputStream* st) const;
+  virtual void print_data_on(outputStream* st, const char* extra = NULL) const;
 #endif
 
   static ByteSize stack_slot_offset(int i) {
@@ -1737,6 +1751,54 @@ public:
   }
 };
 
+// SpeculativeTrapData
+//
+// A SpeculativeTrapData is used to record traps due to type
+// speculation. It records the root of the compilation: that type
+// speculation is wrong in the context of one compilation (for
+// method1) doesn't mean it's wrong in the context of another one (for
+// method2). Type speculation could have more/different data in the
+// context of the compilation of method2 and it's worthwhile to try an
+// optimization that failed for compilation of method1 in the context
+// of compilation of method2.
+// Space for SpeculativeTrapData entries is allocated from the extra
+// data space in the MDO. If we run out of space, the trap data for
+// the ProfileData at that bci is updated.
+class SpeculativeTrapData : public ProfileData {
+protected:
+  enum {
+    method_offset,
+    speculative_trap_cell_count
+  };
+public:
+  SpeculativeTrapData(DataLayout* layout) : ProfileData(layout) {
+    assert(layout->tag() == DataLayout::speculative_trap_data_tag, "wrong type");
+  }
+
+  virtual bool is_SpeculativeTrapData() const { return true; }
+
+  static int static_cell_count() {
+    return speculative_trap_cell_count;
+  }
+
+  virtual int cell_count() const {
+    return static_cell_count();
+  }
+
+  // Direct accessor
+  Method* method() const {
+    return (Method*)intptr_at(method_offset);
+  }
+
+  void set_method(Method* m) {
+    set_intptr_at(method_offset, (intptr_t)m);
+  }
+
+#ifndef PRODUCT
+  virtual void print_data_on(outputStream* st, const char* extra = NULL) const;
+#endif
+};
+
 // MethodData*
 //
 // A MethodData* holds information which has been collected about
@@ -1803,7 +1865,7 @@ public:
 
   // Whole-method sticky bits and flags
   enum {
-    _trap_hist_limit    = 17,   // decoupled from Deoptimization::Reason_LIMIT
+    _trap_hist_limit    = 18,   // decoupled from Deoptimization::Reason_LIMIT
     _trap_hist_mask     = max_jubyte,
     _extra_data_count   = 4     // extra DataLayout headers, for trap history
   }; // Public flag values
@@ -1858,6 +1920,7 @@ private:
   // Helper for size computation
   static int compute_data_size(BytecodeStream* stream);
   static int bytecode_cell_count(Bytecodes::Code code);
+  static bool is_speculative_trap_bytecode(Bytecodes::Code code);
   enum { no_profile_data = -1, variable_cell_count = -2 };
 
   // Helper for initialization
@@ -1901,8 +1964,9 @@ private:
   // What is the index of the first data entry?
   int first_di() const { return 0; }
 
+  ProfileData* bci_to_extra_data_helper(int bci, Method* m, DataLayout*& dp);
   // Find or create an extra ProfileData:
-  ProfileData* bci_to_extra_data(int bci, bool create_if_missing);
+  ProfileData* bci_to_extra_data(int bci, Method* m, bool create_if_missing);
 
   // return the argument info cell
   ArgInfoData *arg_info();
@@ -1925,6 +1989,10 @@ private:
   static bool profile_parameters_jsr292_only();
   static bool profile_all_parameters();
 
+  void clean_extra_data(BoolObjectClosure* is_alive);
+  void clean_extra_data_helper(DataLayout* dp, int shift, bool reset = false);
+  void verify_extra_data_clean(BoolObjectClosure* is_alive);
+
 public:
   static int header_size() {
     return sizeof(MethodData)/wordSize;
@@ -1933,7 +2001,7 @@ public:
   // Compute the size of a MethodData* before it is created.
   static int compute_allocation_size_in_bytes(methodHandle method);
   static int compute_allocation_size_in_words(methodHandle method);
-  static int compute_extra_data_count(int data_size, int empty_bc_count);
+  static int compute_extra_data_count(int data_size, int empty_bc_count, bool needs_speculative_traps);
 
   // Determine if a given bytecode can have profile information.
   static bool bytecode_has_profile(Bytecodes::Code code) {
@@ -2074,9 +2142,26 @@ public:
   ProfileData* bci_to_data(int bci);
 
   // Same, but try to create an extra_data record if one is needed:
-  ProfileData* allocate_bci_to_data(int bci) {
-    ProfileData* data = bci_to_data(bci);
-    return (data != NULL) ? data : bci_to_extra_data(bci, true);
+  ProfileData* allocate_bci_to_data(int bci, Method* m) {
+    ProfileData* data = NULL;
+    // If m not NULL, try to allocate a SpeculativeTrapData entry
+    if (m == NULL) {
+      data = bci_to_data(bci);
+    }
+    if (data != NULL) {
+      return data;
+    }
+    data = bci_to_extra_data(bci, m, true);
+    if (data != NULL) {
+      return data;
+    }
+    // If SpeculativeTrapData allocation fails try to allocate a
+    // regular entry
+    data = bci_to_data(bci);
+    if (data != NULL) {
+      return data;
+    }
+    return bci_to_extra_data(bci, NULL, true);
   }
 
   // Add a handful of extra data records, for trap tracking.
@@ -2084,7 +2169,7 @@ public:
   DataLayout* extra_data_limit() const { return (DataLayout*)((address)this + size_in_bytes()); }
   int extra_data_size() const { return (address)extra_data_limit()
                                - (address)extra_data_base(); }
-  static DataLayout* next_extra(DataLayout* dp) { return (DataLayout*)((address)dp + in_bytes(DataLayout::cell_offset(0))); }
+  static DataLayout* next_extra(DataLayout* dp);
 
   // Return (uint)-1 for overflow.
   uint trap_count(int reason) const {
@@ -2184,6 +2269,8 @@ public:
   static bool profile_return();
   static bool profile_parameters();
   static bool profile_return_jsr292_only();
+
+  void clean_method_data(BoolObjectClosure* is_alive);
 };
 
 #endif // SHARE_VM_OOPS_METHODDATAOOP_HPP

src/share/vm/opto/compile.cpp

@@ -3233,7 +3233,8 @@ bool Compile::too_many_traps(ciMethod* method,
     // because of a transient condition during start-up in the interpreter.
     return false;
   }
-  if (md->has_trap_at(bci, reason) != 0) {
+  ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
+  if (md->has_trap_at(bci, m, reason) != 0) {
     // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
     // Also, if there are multiple reasons, or if there is no per-BCI record,
     // assume the worst.
@@ -3251,7 +3252,7 @@ bool Compile::too_many_traps(ciMethod* method,
 // Less-accurate variant which does not require a method and bci.
 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
                              ciMethodData* logmd) {
- if (trap_count(reason) >= (uint)PerMethodTrapLimit) {
+  if (trap_count(reason) >= Deoptimization::per_method_trap_limit(reason)) {
     // Too many traps globally.
     // Note that we use cumulative trap_count, not just md->trap_count.
     if (log()) {
@@ -3286,10 +3287,11 @@ bool Compile::too_many_recompiles(ciMethod* method,
   uint m_cutoff  = (uint) PerMethodRecompilationCutoff / 2 + 1;  // not zero
   Deoptimization::DeoptReason per_bc_reason
     = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
+  ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
   if ((per_bc_reason == Deoptimization::Reason_none
-       || md->has_trap_at(bci, reason) != 0)
+       || md->has_trap_at(bci, m, reason) != 0)
       // The trap frequency measure we care about is the recompile count:
-      && md->trap_recompiled_at(bci)
+      && md->trap_recompiled_at(bci, m)
       && md->overflow_recompile_count() >= bc_cutoff) {
     // Do not emit a trap here if it has already caused recompilations.
     // Also, if there are multiple reasons, or if there is no per-BCI record,

src/share/vm/opto/doCall.cpp

@@ -250,7 +250,7 @@ CallGenerator* Compile::call_generator(ciMethod* callee, int vtable_index, bool
           CallGenerator* miss_cg;
           Deoptimization::DeoptReason reason = morphism == 2 ?
                                     Deoptimization::Reason_bimorphic :
-                                    Deoptimization::Reason_class_check;
+                                    (speculative_receiver_type == NULL ? Deoptimization::Reason_class_check : Deoptimization::Reason_speculate_class_check);
           if ((morphism == 1 || (morphism == 2 && next_hit_cg != NULL)) &&
               !too_many_traps(jvms->method(), jvms->bci(), reason)
              ) {

src/share/vm/opto/graphKit.cpp

@@ -611,9 +611,10 @@ void GraphKit::builtin_throw(Deoptimization::DeoptReason reason, Node* arg) {
   // Usual case:  Bail to interpreter.
   // Reserve the right to recompile if we haven't seen anything yet.
 
+  assert(!Deoptimization::reason_is_speculate(reason), "unsupported");
   Deoptimization::DeoptAction action = Deoptimization::Action_maybe_recompile;
   if (treat_throw_as_hot
-      && (method()->method_data()->trap_recompiled_at(bci())
+      && (method()->method_data()->trap_recompiled_at(bci(), NULL)
           || C->too_many_traps(reason))) {
     // We cannot afford to take more traps here.  Suffer in the interpreter.
     if (C->log() != NULL)
@@ -2141,7 +2142,7 @@ Node* GraphKit::record_profile_for_speculation(Node* n, ciKlass* exact_kls) {
  *
  * @param n  receiver node
  *
- * @return           node with improved type
+ * @return   node with improved type
  */
 Node* GraphKit::record_profiled_receiver_for_speculation(Node* n) {
   if (!UseTypeSpeculation) {
@@ -2734,12 +2735,14 @@ bool GraphKit::seems_never_null(Node* obj, ciProfileData* data) {
 // Subsequent type checks will always fold up.
 Node* GraphKit::maybe_cast_profiled_receiver(Node* not_null_obj,
                                              ciKlass* require_klass,
-                                            ciKlass* spec_klass,
+                                             ciKlass* spec_klass,
                                              bool safe_for_replace) {
   if (!UseTypeProfile || !TypeProfileCasts) return NULL;
 
+  Deoptimization::DeoptReason reason = spec_klass == NULL ? Deoptimization::Reason_class_check : Deoptimization::Reason_speculate_class_check;
+
   // Make sure we haven't already deoptimized from this tactic.
-  if (too_many_traps(Deoptimization::Reason_class_check))
+  if (too_many_traps(reason))
     return NULL;
 
   // (No, this isn't a call, but it's enough like a virtual call
@@ -2761,7 +2764,7 @@ Node* GraphKit::maybe_cast_profiled_receiver(Node* not_null_obj,
                                             &exact_obj);
       { PreserveJVMState pjvms(this);
         set_control(slow_ctl);
-        uncommon_trap(Deoptimization::Reason_class_check,
+        uncommon_trap(reason,
                       Deoptimization::Action_maybe_recompile);
       }
       if (safe_for_replace) {
@@ -2788,8 +2791,10 @@ Node* GraphKit::maybe_cast_profiled_obj(Node* obj,
                                         bool not_null) {
   // type == NULL if profiling tells us this object is always null
   if (type != NULL) {
-    if (!too_many_traps(Deoptimization::Reason_null_check) &&
-        !too_many_traps(Deoptimization::Reason_class_check)) {
+    Deoptimization::DeoptReason class_reason = Deoptimization::Reason_speculate_class_check;
+    Deoptimization::DeoptReason null_reason = Deoptimization::Reason_null_check;
+    if (!too_many_traps(null_reason) &&
+        !too_many_traps(class_reason)) {
       Node* not_null_obj = NULL;
       // not_null is true if we know the object is not null and
       // there's no need for a null check
@@ -2808,7 +2813,7 @@ Node* GraphKit::maybe_cast_profiled_obj(Node* obj,
       {
         PreserveJVMState pjvms(this);
         set_control(slow_ctl);
-        uncommon_trap(Deoptimization::Reason_class_check,
+        uncommon_trap(class_reason,
                       Deoptimization::Action_maybe_recompile);
       }
       replace_in_map(not_null_obj, exact_obj);
@@ -2877,7 +2882,7 @@ Node* GraphKit::gen_instanceof(Node* obj, Node* superklass, bool safe_for_replac
   }
 
   if (known_statically && UseTypeSpeculation) {
-    // If we know the type check always succeed then we don't use the
+    // If we know the type check always succeeds then we don't use the
     // profiling data at this bytecode. Don't lose it, feed it to the
     // type system as a speculative type.
     not_null_obj = record_profiled_receiver_for_speculation(not_null_obj);

src/share/vm/opto/graphKit.hpp

@@ -406,7 +406,7 @@ class GraphKit : public Phase {
   // Use the type profile to narrow an object type.
   Node* maybe_cast_profiled_receiver(Node* not_null_obj,
                                      ciKlass* require_klass,
-                                    ciKlass* spec,
+                                     ciKlass* spec,
                                      bool safe_for_replace);
 
   // Cast obj to type and emit guard unless we had too many traps here already

src/share/vm/runtime/deoptimization.cpp

@@ -1486,6 +1486,7 @@ JRT_ENTRY(void, Deoptimization::uncommon_trap_inner(JavaThread* thread, jint tra
       bool maybe_prior_trap = false;
       bool maybe_prior_recompile = false;
       pdata = query_update_method_data(trap_mdo, trap_bci, reason,
+                                   nm->method(),
                                    //outputs:
                                    this_trap_count,
                                    maybe_prior_trap,
@@ -1531,7 +1532,7 @@ JRT_ENTRY(void, Deoptimization::uncommon_trap_inner(JavaThread* thread, jint tra
       }
 
       // Go back to the compiler if there are too many traps in this method.
-      if (this_trap_count >= (uint)PerMethodTrapLimit) {
+      if (this_trap_count >= per_method_trap_limit(reason)) {
         // If there are too many traps in this method, force a recompile.
         // This will allow the compiler to see the limit overflow, and
         // take corrective action, if possible.
@@ -1619,6 +1620,7 @@ ProfileData*
 Deoptimization::query_update_method_data(MethodData* trap_mdo,
                                          int trap_bci,
                                          Deoptimization::DeoptReason reason,
+                                         Method* compiled_method,
                                          //outputs:
                                          uint& ret_this_trap_count,
                                          bool& ret_maybe_prior_trap,
@@ -1642,9 +1644,16 @@ Deoptimization::query_update_method_data(MethodData* trap_mdo,
     // Find the profile data for this BCI.  If there isn't one,
     // try to allocate one from the MDO's set of spares.
     // This will let us detect a repeated trap at this point.
-    pdata = trap_mdo->allocate_bci_to_data(trap_bci);
+    pdata = trap_mdo->allocate_bci_to_data(trap_bci, reason_is_speculate(reason) ? compiled_method : NULL);
 
     if (pdata != NULL) {
+      if (reason_is_speculate(reason) && !pdata->is_SpeculativeTrapData()) {
+        if (LogCompilation && xtty != NULL) {
+          ttyLocker ttyl;
+          // no more room for speculative traps in this MDO
+          xtty->elem("speculative_traps_oom");
+        }
+      }
       // Query the trap state of this profile datum.
       int tstate0 = pdata->trap_state();
       if (!trap_state_has_reason(tstate0, per_bc_reason))
@@ -1682,8 +1691,10 @@ Deoptimization::update_method_data_from_interpreter(MethodData* trap_mdo, int tr
   uint ignore_this_trap_count;
   bool ignore_maybe_prior_trap;
   bool ignore_maybe_prior_recompile;
+  assert(!reason_is_speculate(reason), "reason speculate only used by compiler");
   query_update_method_data(trap_mdo, trap_bci,
                            (DeoptReason)reason,
+                           NULL,
                            ignore_this_trap_count,
                            ignore_maybe_prior_trap,
                            ignore_maybe_prior_recompile);
@@ -1811,7 +1822,8 @@ const char* Deoptimization::_trap_reason_name[Reason_LIMIT] = {
   "div0_check",
   "age",
   "predicate",
-  "loop_limit_check"
+  "loop_limit_check",
+  "speculate_class_check"
 };
 const char* Deoptimization::_trap_action_name[Action_LIMIT] = {
   // Note:  Keep this in sync. with enum DeoptAction.

src/share/vm/runtime/deoptimization.hpp

@@ -59,6 +59,7 @@ class Deoptimization : AllStatic {
     Reason_age,                   // nmethod too old; tier threshold reached
     Reason_predicate,             // compiler generated predicate failed
     Reason_loop_limit_check,      // compiler generated loop limits check failed
+    Reason_speculate_class_check, // saw unexpected object class from type speculation
     Reason_LIMIT,
     // Note:  Keep this enum in sync. with _trap_reason_name.
     Reason_RECORDED_LIMIT = Reason_bimorphic  // some are not recorded per bc
@@ -311,10 +312,23 @@ class Deoptimization : AllStatic {
       return reason;
     else if (reason == Reason_div0_check) // null check due to divide-by-zero?
       return Reason_null_check;           // recorded per BCI as a null check
+    else if (reason == Reason_speculate_class_check)
+      return Reason_class_check;
     else
       return Reason_none;
   }
 
+  static bool reason_is_speculate(int reason) {
+    if (reason == Reason_speculate_class_check) {
+      return true;
+    }
+    return false;
+  }
+
+  static uint per_method_trap_limit(int reason) {
+    return reason_is_speculate(reason) ? (uint)PerMethodSpecTrapLimit : (uint)PerMethodTrapLimit;
+  }
+
   static const char* trap_reason_name(int reason);
   static const char* trap_action_name(int action);
   // Format like reason='foo' action='bar' index='123'.
@@ -337,6 +351,7 @@ class Deoptimization : AllStatic {
   static ProfileData* query_update_method_data(MethodData* trap_mdo,
                                                int trap_bci,
                                                DeoptReason reason,
+                                               Method* compiled_method,
                                                //outputs:
                                                uint& ret_this_trap_count,
                                                bool& ret_maybe_prior_trap,

src/share/vm/runtime/globals.hpp

@@ -3055,9 +3055,15 @@ class CommandLineFlags {
   product(intx, PerMethodTrapLimit,  100,                                   \
           "Limit on traps (of one kind) in a method (includes inlines)")    \
                                                                             \
+  experimental(intx, PerMethodSpecTrapLimit,  5000,                         \
+          "Limit on speculative traps (of one kind) in a method (includes inlines)") \
+                                                                            \
   product(intx, PerBytecodeTrapLimit,  4,                                   \
           "Limit on traps (of one kind) at a particular BCI")               \
                                                                             \
+  experimental(intx, SpecTrapLimitExtraEntries,  3,                         \
+          "Extra method data trap entries for speculation")                 \
+                                                                            \
   develop(intx, InlineFrequencyRatio,    20,                                \
           "Ratio of call site execution to caller method invocation")       \
                                                                             \

test/compiler/uncommontrap/TestSpecTrapClassUnloading.java

+/*
+ * Copyright (c) 2014, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8031752
+ * @summary speculative traps need to be cleaned up at GC
+ * @run main/othervm -XX:-TieredCompilation -XX:-UseOnStackReplacement -XX:-BackgroundCompilation -XX:+UnlockExperimentalVMOptions -XX:+UseTypeSpeculation -XX:TypeProfileLevel=222 -XX:CompileCommand=exclude,java.lang.reflect.Method::invoke -XX:CompileCommand=exclude,sun.reflect.DelegatingMethodAccessorImpl::invoke -Xmx1M TestSpecTrapClassUnloading
+ *
+ */
+
+import java.lang.reflect.Method;
+
+public class TestSpecTrapClassUnloading {
+    static class B {
+        final public boolean m(Object o) {
+            if (o.getClass() == B.class) {
+                return true;
+            }
+            return false;
+        }
+    }
+
+    static class MemoryChunk {
+        MemoryChunk other;
+        long[] array;
+        MemoryChunk(MemoryChunk other) {
+            other = other;
+            array = new long[1024 * 1024 * 1024];
+        }
+    }
+
+    static void m1(B b, Object o) {
+        b.m(o);
+    }
+
+    static void m2(B b, Object o) {
+        b.m(o);
+    }
+
+    public static void main(String[] args) throws Exception {
+        Method m = B.class.getMethod("m", Object.class);
+        Object o = new Object();
+        B b = new B();
+
+        // add speculative trap in B.m() for m1
+        for (int i = 0; i < 20000; i++) {
+            m1(b, b);
+        }
+        m1(b, o);
+
+        // add speculative trap in B.m() for code generated by reflection
+        for (int i = 0; i < 20000; i++) {
+            m.invoke(b, b);
+        }
+        m.invoke(b, o);
+
+        m = null;
+
+        // add speculative trap in B.m() for m2
+        for (int i = 0; i < 20000; i++) {
+            m2(b, b);
+        }
+        m2(b, o);
+
+        // Exhaust memory which causes the code generated by
+        // reflection to be unloaded but B.m() is not.
+        MemoryChunk root = null;
+        try {
+            while (true) {
+                root = new MemoryChunk(root);
+            }
+        } catch(OutOfMemoryError e) {
+            root = null;
+        }
+    }
+}