dump heap when we see dangling threads for debugging

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/GraalPythonModuleBuiltins.java

@@ -45,6 +45,7 @@
 import static com.oracle.graal.python.runtime.exception.PythonErrorType.ImportError;
 import static com.oracle.graal.python.runtime.exception.PythonErrorType.NotImplementedError;
 
+import java.io.IOException;
 import java.io.PrintWriter;
 import java.util.List;
 import java.util.logging.Level;
@@ -683,4 +684,21 @@ Object doIt(Object value) {
         }
     }
 
+    @Builtin(name = "dump_heap", minNumOfPositionalArgs = 0)
+    @GenerateNodeFactory
+    abstract static class DumpHeapNode extends PythonBuiltinNode {
+        @Specialization
+        String doit(VirtualFrame frame, @CachedContext(PythonLanguage.class) PythonContext context) {
+            TruffleFile tempFile;
+            try {
+                tempFile = context.getEnv().createTempFile(context.getEnv().getCurrentWorkingDirectory(), "graalpython", ".hprof");
+                tempFile.delete();
+            } catch (IOException e) {
+                throw raiseOSError(frame, e);
+            }
+            PythonUtils.dumpHeap(tempFile.getPath());
+            return tempFile.getPath();
+        }
+    }
+
 }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/util/PythonUtils.java

@@ -297,6 +297,22 @@ public static void forceFullGC() {
         Runtime.getRuntime().freeMemory();
     }
 
+    @TruffleBoundary
+    public static void dumpHeap(String path) {
+        if (SERVER != null) {
+            try {
+                Class<?> mxBeanClass = Class.forName("com.sun.management.HotSpotDiagnosticMXBean");
+                Object mxBean = ManagementFactory.newPlatformMXBeanProxy(SERVER,
+                                "com.sun.management:type=HotSpotDiagnostic",
+                                mxBeanClass);
+                mxBeanClass.getMethod("dumpHeap", String.class, boolean.class).invoke(mxBean, path, true);
+            } catch (Throwable e) {
+                System.err.println("Cannot dump heap: " + e.getMessage());
+                e.printStackTrace();
+            }
+        }
+    }
+
     /**
      * Get the existing or create a new {@link CallTarget} for the provided root node.
      */