# HG changeset patch
# User kvn
# Date 1386360711 28800
# Node ID 82e95c56213347ffa2085d22e16e0280a45a3b27
# Parent  45a293a4b89586be9251054c248e4b2c23424433
8028107: Kitchensink crashed with EAV
Summary: check the state of caller and callee nmethods and skip call site patching if any of them is not alive
Reviewed-by: jrose, twisti

diff -r 45a293a4b895 -r 82e95c562133 hotspot/src/share/vm/code/compiledIC.cpp
--- a/hotspot/src/share/vm/code/compiledIC.cpp	Mon Dec 09 10:03:39 2013 +0100
+++ b/hotspot/src/share/vm/code/compiledIC.cpp	Fri Dec 06 12:11:51 2013 -0800
@@ -418,7 +418,7 @@
                                            TRAPS) {
   nmethod* method_code = method->code();
   address entry = NULL;
-  if (method_code != NULL) {
+  if (method_code != NULL && method_code->is_in_use()) {
     // Call to compiled code
     if (static_bound || is_optimized) {
       entry      = method_code->verified_entry_point();
@@ -545,7 +545,7 @@
 void CompiledStaticCall::compute_entry(methodHandle m, StaticCallInfo& info) {
   nmethod* m_code = m->code();
   info._callee = m;
-  if (m_code != NULL) {
+  if (m_code != NULL && m_code->is_in_use()) {
     info._to_interpreter = false;
     info._entry  = m_code->verified_entry_point();
   } else {
diff -r 45a293a4b895 -r 82e95c562133 hotspot/src/share/vm/code/nmethod.cpp
--- a/hotspot/src/share/vm/code/nmethod.cpp	Mon Dec 09 10:03:39 2013 +0100
+++ b/hotspot/src/share/vm/code/nmethod.cpp	Fri Dec 06 12:11:51 2013 -0800
@@ -459,7 +459,7 @@
 
 // Fill in default values for various flag fields
 void nmethod::init_defaults() {
-  _state                      = alive;
+  _state                      = in_use;
   _marked_for_reclamation     = 0;
   _has_flushed_dependencies   = 0;
   _has_unsafe_access          = 0;
@@ -1660,8 +1660,8 @@
           CompiledICHolder* cichk_oop = ic->cached_icholder();
           if (cichk_oop->holder_method()->method_holder()->is_loader_alive(is_alive) &&
               cichk_oop->holder_klass()->is_loader_alive(is_alive)) {
-              continue;
-            }
+            continue;
+          }
         } else {
           Metadata* ic_oop = ic->cached_metadata();
           if (ic_oop != NULL) {
@@ -1677,8 +1677,8 @@
               ShouldNotReachHere();
             }
           }
-          }
-          ic->set_to_clean();
+        }
+        ic->set_to_clean();
       }
     }
   }
@@ -2393,8 +2393,8 @@
 
 void nmethod::verify_interrupt_point(address call_site) {
   // Verify IC only when nmethod installation is finished.
-  bool is_installed = (method()->code() == this) // nmethod is in state 'alive' and installed
-                      || !this->is_in_use();     // nmethod is installed, but not in 'alive' state
+  bool is_installed = (method()->code() == this) // nmethod is in state 'in_use' and installed
+                      || !this->is_in_use();     // nmethod is installed, but not in 'in_use' state
   if (is_installed) {
     Thread *cur = Thread::current();
     if (CompiledIC_lock->owner() == cur ||
diff -r 45a293a4b895 -r 82e95c562133 hotspot/src/share/vm/code/nmethod.hpp
--- a/hotspot/src/share/vm/code/nmethod.hpp	Mon Dec 09 10:03:39 2013 +0100
+++ b/hotspot/src/share/vm/code/nmethod.hpp	Fri Dec 06 12:11:51 2013 -0800
@@ -184,11 +184,12 @@
   bool _oops_are_stale;  // indicates that it's no longer safe to access oops section
 #endif
 
-  enum { alive        = 0,
-         not_entrant  = 1, // uncommon trap has happened but activations may still exist
-         zombie       = 2,
-         unloaded     = 3 };
-
+  enum { in_use       = 0,   // executable nmethod
+         not_entrant  = 1,   // marked for deoptimization but activations may still exist,
+                             // will be transformed to zombie when all activations are gone
+         zombie       = 2,   // no activations exist, nmethod is ready for purge
+         unloaded     = 3 }; // there should be no activations, should not be called,
+                             // will be transformed to zombie immediately
 
   jbyte _scavenge_root_state;
 
@@ -407,8 +408,8 @@
   address verified_entry_point() const            { return _verified_entry_point;    } // if klass is correct
 
   // flag accessing and manipulation
-  bool  is_in_use() const                         { return _state == alive; }
-  bool  is_alive() const                          { return _state == alive || _state == not_entrant; }
+  bool  is_in_use() const                         { return _state == in_use; }
+  bool  is_alive() const                          { return _state == in_use || _state == not_entrant; }
   bool  is_not_entrant() const                    { return _state == not_entrant; }
   bool  is_zombie() const                         { return _state == zombie; }
   bool  is_unloaded() const                       { return _state == unloaded;   }
diff -r 45a293a4b895 -r 82e95c562133 hotspot/src/share/vm/runtime/sharedRuntime.cpp
--- a/hotspot/src/share/vm/runtime/sharedRuntime.cpp	Mon Dec 09 10:03:39 2013 +0100
+++ b/hotspot/src/share/vm/runtime/sharedRuntime.cpp	Fri Dec 06 12:11:51 2013 -0800
@@ -1178,12 +1178,12 @@
   CodeBlob* caller_cb = caller_frame.cb();
   guarantee(caller_cb != NULL && caller_cb->is_nmethod(), "must be called from nmethod");
   nmethod* caller_nm = caller_cb->as_nmethod_or_null();
+
   // make sure caller is not getting deoptimized
   // and removed before we are done with it.
   // CLEANUP - with lazy deopt shouldn't need this lock
   nmethodLocker caller_lock(caller_nm);
 
-
   // determine call info & receiver
   // note: a) receiver is NULL for static calls
   //       b) an exception is thrown if receiver is NULL for non-static calls
@@ -1198,6 +1198,11 @@
          (!is_virtual && invoke_code == Bytecodes::_invokedynamic) ||
          ( is_virtual && invoke_code != Bytecodes::_invokestatic ), "inconsistent bytecode");
 
+  // We do not patch the call site if the caller nmethod has been made non-entrant.
+  if (!caller_nm->is_in_use()) {
+    return callee_method;
+  }
+
 #ifndef PRODUCT
   // tracing/debugging/statistics
   int *addr = (is_optimized) ? (&_resolve_opt_virtual_ctr) :
@@ -1237,6 +1242,10 @@
   // Make sure the callee nmethod does not get deoptimized and removed before
   // we are done patching the code.
   nmethod* callee_nm = callee_method->code();
+  if (callee_nm != NULL && !callee_nm->is_in_use()) {
+    // Patch call site to C2I adapter if callee nmethod is deoptimized or unloaded.
+    callee_nm = NULL;
+  }
   nmethodLocker nl_callee(callee_nm);
 #ifdef ASSERT
   address dest_entry_point = callee_nm == NULL ? 0 : callee_nm->entry_point(); // used below
@@ -1258,15 +1267,24 @@
   {
     MutexLocker ml_patch(CompiledIC_lock);
 
+    // Lock blocks for safepoint during which both nmethods can change state.
+
     // Now that we are ready to patch if the Method* was redefined then
     // don't update call site and let the caller retry.
-
-    if (!callee_method->is_old()) {
+    // Don't update call site if caller nmethod has been made non-entrant
+    // as it is a waste of time.
+    // Don't update call site if callee nmethod was unloaded or deoptimized.
+    // Don't update call site if callee nmethod was replaced by an other nmethod
+    // which may happen when multiply alive nmethod (tiered compilation)
+    // will be supported.
+    if (!callee_method->is_old() && caller_nm->is_in_use() &&
+        (callee_nm == NULL || callee_nm->is_in_use() && (callee_method->code() == callee_nm))) {
 #ifdef ASSERT
       // We must not try to patch to jump to an already unloaded method.
       if (dest_entry_point != 0) {
-        assert(CodeCache::find_blob(dest_entry_point) != NULL,
-               "should not unload nmethod while locked");
+        CodeBlob* cb = CodeCache::find_blob(dest_entry_point);
+        assert((cb != NULL) && cb->is_nmethod() && (((nmethod*)cb) == callee_nm),
+               "should not call unloaded nmethod");
       }
 #endif
       if (is_virtual) {