GR-63795: restore com.oracle.svm.core.thread.Safepoint.existSlowPathCheck()

Author: synecdoche

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/thread/Safepoint.java

@@ -65,10 +65,12 @@
 import com.oracle.svm.core.nodes.SafepointCheckNode;
 import com.oracle.svm.core.option.HostedOptionKey;
 import com.oracle.svm.core.option.RuntimeOptionKey;
+import com.oracle.svm.core.snippets.KnownIntrinsics;
 import com.oracle.svm.core.snippets.SnippetRuntime;
 import com.oracle.svm.core.snippets.SnippetRuntime.SubstrateForeignCallDescriptor;
 import com.oracle.svm.core.snippets.SubstrateForeignCallTarget;
 import com.oracle.svm.core.stack.JavaFrameAnchors;
+import com.oracle.svm.core.thread.VMThreads.ActionOnExitSafepointSupport;
 import com.oracle.svm.core.thread.VMThreads.ActionOnTransitionToJavaSupport;
 import com.oracle.svm.core.thread.VMThreads.SafepointBehavior;
 import com.oracle.svm.core.thread.VMThreads.StatusSupport;
@@ -196,6 +198,7 @@ private static void slowPathSafepointCheck(int newStatus, boolean callerHasJavaF
              */
             VMError.shouldNotReachHere(ex);
         }
+        exitSlowPathCheck();
     }
 
     /**
@@ -422,6 +425,18 @@ public static void slowPathSafepointCheck() throws Throwable {
         slowPathSafepointCheck(StatusSupport.STATUS_IN_JAVA, false, false);
     }
 
+    @Uninterruptible(reason = "Must not contain safepoint checks")
+    private static void exitSlowPathCheck() {
+        if (ActionOnExitSafepointSupport.isActionPending()) {
+            if (LoomSupport.isEnabled() && ActionOnExitSafepointSupport.isSwitchStackPending()) {
+                ActionOnExitSafepointSupport.clearActions();
+                KnownIntrinsics.farReturn(0, ActionOnExitSafepointSupport.getSwitchStackSP(), ActionOnExitSafepointSupport.getSwitchStackIP(), false);
+            } else {
+                assert false : "Unexpected action pending.";
+            }
+        }
+    }
+
     /**
      * Transition from native to Java, checking for safepoint.
      *