src/hotspot/share/code/nmethod.cpp

rev 54936 : [mq]: 8221734-v3

*** 47,56 ****
--- 47,57 ----
  #include "oops/method.inline.hpp"
  #include "oops/methodData.hpp"
  #include "oops/oop.inline.hpp"
  #include "prims/jvmtiImpl.hpp"
  #include "runtime/atomic.hpp"
+ #include "runtime/deoptimization.hpp"
  #include "runtime/flags/flagSetting.hpp"
  #include "runtime/frame.inline.hpp"
  #include "runtime/handles.inline.hpp"
  #include "runtime/jniHandles.inline.hpp"
  #include "runtime/orderAccess.hpp"
*** 1119,1133 ****
    // If _method is already NULL the Method* is about to be unloaded,
    // so we don't have to break the cycle. Note that it is possible to
    // have the Method* live here, in case we unload the nmethod because
    // it is pointing to some oop (other than the Method*) being unloaded.
    if (_method != NULL) {
!     // OSR methods point to the Method*, but the Method* does not
!     // point back!
!     if (_method->code() == this) {
!       _method->clear_code(); // Break a cycle
!     }
    }
  
    // Make the class unloaded - i.e., change state and notify sweeper
    assert(SafepointSynchronize::is_at_safepoint() || Thread::current()->is_ConcurrentGC_thread(),
           "must be at safepoint");
--- 1120,1130 ----
    // If _method is already NULL the Method* is about to be unloaded,
    // so we don't have to break the cycle. Note that it is possible to
    // have the Method* live here, in case we unload the nmethod because
    // it is pointing to some oop (other than the Method*) being unloaded.
    if (_method != NULL) {
!     _method->unlink_code(this);
    }
  
    // Make the class unloaded - i.e., change state and notify sweeper
    assert(SafepointSynchronize::is_at_safepoint() || Thread::current()->is_ConcurrentGC_thread(),
           "must be at safepoint");
*** 1205,1224 ****
    if (PrintCompilation && _state != unloaded) {
      print_on(tty, state_msg);
    }
  }
  
! void nmethod::unlink_from_method(bool acquire_lock) {
!   // We need to check if both the _code and _from_compiled_code_entry_point
!   // refer to this nmethod because there is a race in setting these two fields
!   // in Method* as seen in bugid 4947125.
!   // If the vep() points to the zombie nmethod, the memory for the nmethod
!   // could be flushed and the compiler and vtable stubs could still call
!   // through it.
!   if (method() != NULL && (method()->code() == this ||
!                            method()->from_compiled_entry() == verified_entry_point())) {
!     method()->clear_code(acquire_lock);
    }
  }
  
  /**
   * Common functionality for both make_not_entrant and make_zombie
--- 1202,1214 ----
    if (PrintCompilation && _state != unloaded) {
      print_on(tty, state_msg);
    }
  }
  
! void nmethod::unlink_from_method() {
!   if (method() != NULL) {
!     method()->unlink_code();
    }
  }
  
  /**
   * Common functionality for both make_not_entrant and make_zombie
*** 1241,1268 ****
    // This can be called while the system is already at a safepoint which is ok
    NoSafepointVerifier nsv(true, !SafepointSynchronize::is_at_safepoint());
  
    // during patching, depending on the nmethod state we must notify the GC that
    // code has been unloaded, unregistering it. We cannot do this right while
!   // holding the Patching_lock because we need to use the CodeCache_lock. This
    // would be prone to deadlocks.
    // This flag is used to remember whether we need to later lock and unregister.
    bool nmethod_needs_unregister = false;
  
-   {
      // invalidate osr nmethod before acquiring the patching lock since
      // they both acquire leaf locks and we don't want a deadlock.
      // This logic is equivalent to the logic below for patching the
      // verified entry point of regular methods. We check that the
      // nmethod is in use to ensure that it is invalidated only once.
      if (is_osr_method() && is_in_use()) {
        // this effectively makes the osr nmethod not entrant
        invalidate_osr_method();
      }
  
      // Enter critical section.  Does not block for safepoint.
!     MutexLocker pl(Patching_lock, Mutex::_no_safepoint_check_flag);
  
      if (_state == state) {
        // another thread already performed this transition so nothing
        // to do, but return false to indicate this.
        return false;
--- 1231,1258 ----
    // This can be called while the system is already at a safepoint which is ok
    NoSafepointVerifier nsv(true, !SafepointSynchronize::is_at_safepoint());
  
    // during patching, depending on the nmethod state we must notify the GC that
    // code has been unloaded, unregistering it. We cannot do this right while
!   // holding the CompiledMethod_lock because we need to use the CodeCache_lock. This
    // would be prone to deadlocks.
    // This flag is used to remember whether we need to later lock and unregister.
    bool nmethod_needs_unregister = false;
  
    // invalidate osr nmethod before acquiring the patching lock since
    // they both acquire leaf locks and we don't want a deadlock.
    // This logic is equivalent to the logic below for patching the
    // verified entry point of regular methods. We check that the
    // nmethod is in use to ensure that it is invalidated only once.
    if (is_osr_method() && is_in_use()) {
      // this effectively makes the osr nmethod not entrant
      invalidate_osr_method();
    }
  
+   {
      // Enter critical section.  Does not block for safepoint.
!     MutexLocker pl(CompiledMethod_lock, Mutex::_no_safepoint_check_flag);
  
      if (_state == state) {
        // another thread already performed this transition so nothing
        // to do, but return false to indicate this.
        return false;
*** 1302,1313 ****
  
      // Log the transition once
      log_state_change();
  
      // Remove nmethod from method.
!     unlink_from_method(false /* already owns Patching_lock */);
!   } // leave critical region under Patching_lock
  
  #if INCLUDE_JVMCI
    // Invalidate can't occur while holding the Patching lock
    JVMCINMethodData* nmethod_data = jvmci_nmethod_data();
    if (nmethod_data != NULL) {
--- 1292,1304 ----
  
      // Log the transition once
      log_state_change();
  
      // Remove nmethod from method.
!     unlink_from_method();
! 
!   } // leave critical region under CompiledMethod_lock
  
  #if INCLUDE_JVMCI
    // Invalidate can't occur while holding the Patching lock
    JVMCINMethodData* nmethod_data = jvmci_nmethod_data();
    if (nmethod_data != NULL) {