6951784: Zero deoptimizer changes

Summary: The way Zero currently handles deoptimization can lead to methods being freed while they are still being executed.
Reviewed-by: twisti
Contributed-by: NGary Benson <gbenson@redhat.com>

src/cpu/zero/vm/cppInterpreter_zero.cpp

@@ -37,15 +37,18 @@
   thread->reset_last_Java_frame();              \
   fixup_after_potential_safepoint()
 
-void CppInterpreter::normal_entry(methodOop method, intptr_t UNUSED, TRAPS) {
+int CppInterpreter::normal_entry(methodOop method, intptr_t UNUSED, TRAPS) {
   JavaThread *thread = (JavaThread *) THREAD;
 
   // Allocate and initialize our frame.
-  InterpreterFrame *frame = InterpreterFrame::build(method, CHECK);
+  InterpreterFrame *frame = InterpreterFrame::build(method, CHECK_0);
   thread->push_zero_frame(frame);
 
   // Execute those bytecodes!
   main_loop(0, THREAD);
+
+  // No deoptimized frames on the stack
+  return 0;
 }
 
 void CppInterpreter::main_loop(int recurse, TRAPS) {
@@ -165,7 +168,7 @@ void CppInterpreter::main_loop(int recurse, TRAPS) {
     stack->push(result[-i]);
 }
 
-void CppInterpreter::native_entry(methodOop method, intptr_t UNUSED, TRAPS) {
+int CppInterpreter::native_entry(methodOop method, intptr_t UNUSED, TRAPS) {
   // Make sure method is native and not abstract
   assert(method->is_native() && !method->is_abstract(), "should be");
 
@@ -173,7 +176,7 @@ void CppInterpreter::native_entry(methodOop method, intptr_t UNUSED, TRAPS) {
   ZeroStack *stack = thread->zero_stack();
 
   // Allocate and initialize our frame
-  InterpreterFrame *frame = InterpreterFrame::build(method, CHECK);
+  InterpreterFrame *frame = InterpreterFrame::build(method, CHECK_0);
   thread->push_zero_frame(frame);
   interpreterState istate = frame->interpreter_state();
   intptr_t *locals = istate->locals();
@@ -430,25 +433,26 @@ void CppInterpreter::native_entry(methodOop method, intptr_t UNUSED, TRAPS) {
       ShouldNotReachHere();
     }
   }
+
+  // No deoptimized frames on the stack
+  return 0;
 }
 
-void CppInterpreter::accessor_entry(methodOop method, intptr_t UNUSED, TRAPS) {
+int CppInterpreter::accessor_entry(methodOop method, intptr_t UNUSED, TRAPS) {
   JavaThread *thread = (JavaThread *) THREAD;
   ZeroStack *stack = thread->zero_stack();
   intptr_t *locals = stack->sp();
 
   // Drop into the slow path if we need a safepoint check
   if (SafepointSynchronize::do_call_back()) {
-    normal_entry(method, 0, THREAD);
-    return;
+    return normal_entry(method, 0, THREAD);
   }
 
   // Load the object pointer and drop into the slow path
   // if we have a NullPointerException
   oop object = LOCALS_OBJECT(0);
   if (object == NULL) {
-    normal_entry(method, 0, THREAD);
-    return;
+    return normal_entry(method, 0, THREAD);
   }
 
   // Read the field index from the bytecode, which looks like this:
@@ -470,15 +474,14 @@ void CppInterpreter::accessor_entry(methodOop method, intptr_t UNUSED, TRAPS) {
   constantPoolCacheOop cache = method->constants()->cache();
   ConstantPoolCacheEntry* entry = cache->entry_at(index);
   if (!entry->is_resolved(Bytecodes::_getfield)) {
-    normal_entry(method, 0, THREAD);
-    return;
+    return normal_entry(method, 0, THREAD);
   }
 
   // Get the result and push it onto the stack
   switch (entry->flag_state()) {
   case ltos:
   case dtos:
-    stack->overflow_check(1, CHECK);
+    stack->overflow_check(1, CHECK_0);
     stack->alloc(wordSize);
     break;
   }
@@ -558,20 +561,25 @@ void CppInterpreter::accessor_entry(methodOop method, intptr_t UNUSED, TRAPS) {
       ShouldNotReachHere();
     }
   }
+
+  // No deoptimized frames on the stack
+  return 0;
 }
 
-void CppInterpreter::empty_entry(methodOop method, intptr_t UNUSED, TRAPS) {
+int CppInterpreter::empty_entry(methodOop method, intptr_t UNUSED, TRAPS) {
   JavaThread *thread = (JavaThread *) THREAD;
   ZeroStack *stack = thread->zero_stack();
 
   // Drop into the slow path if we need a safepoint check
   if (SafepointSynchronize::do_call_back()) {
-    normal_entry(method, 0, THREAD);
-    return;
+    return normal_entry(method, 0, THREAD);
   }
 
   // Pop our parameters
   stack->set_sp(stack->sp() + method->size_of_parameters());
+
+  // No deoptimized frames on the stack
+  return 0;
 }
 
 InterpreterFrame *InterpreterFrame::build(const methodOop method, TRAPS) {

src/cpu/zero/vm/cppInterpreter_zero.hpp

@@ -29,10 +29,10 @@
 
  public:
   // Method entries
-  static void normal_entry(methodOop method, intptr_t UNUSED, TRAPS);
-  static void native_entry(methodOop method, intptr_t UNUSED, TRAPS);
-  static void accessor_entry(methodOop method, intptr_t UNUSED, TRAPS);
-  static void empty_entry(methodOop method, intptr_t UNUSED, TRAPS);
+  static int normal_entry(methodOop method, intptr_t UNUSED, TRAPS);
+  static int native_entry(methodOop method, intptr_t UNUSED, TRAPS);
+  static int accessor_entry(methodOop method, intptr_t UNUSED, TRAPS);
+  static int empty_entry(methodOop method, intptr_t UNUSED, TRAPS);
 
  public:
   // Main loop of normal_entry

src/cpu/zero/vm/entry_zero.hpp

 /*
  * Copyright 2003-2007 Sun Microsystems, Inc.  All Rights Reserved.
- * Copyright 2008, 2009 Red Hat, Inc.
+ * Copyright 2008, 2009, 2010 Red Hat, Inc.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,20 +41,30 @@ class ZeroEntry {
   }
 
  private:
-  typedef void (*NormalEntryFunc)(methodOop method,
-                                  intptr_t  base_pc,
-                                  TRAPS);
-  typedef void (*OSREntryFunc)(methodOop method,
-                               address   osr_buf,
-                               intptr_t  base_pc,
-                               TRAPS);
+  typedef int (*NormalEntryFunc)(methodOop method,
+                                 intptr_t  base_pc,
+                                 TRAPS);
+  typedef int (*OSREntryFunc)(methodOop method,
+                              address   osr_buf,
+                              intptr_t  base_pc,
+                              TRAPS);
 
  public:
   void invoke(methodOop method, TRAPS) const {
-    ((NormalEntryFunc) entry_point())(method, (intptr_t) this, THREAD);
+    maybe_deoptimize(
+      ((NormalEntryFunc) entry_point())(method, (intptr_t) this, THREAD),
+      THREAD);
   }
   void invoke_osr(methodOop method, address osr_buf, TRAPS) const {
-    ((OSREntryFunc) entry_point())(method, osr_buf, (intptr_t) this, THREAD);
+    maybe_deoptimize(
+      ((OSREntryFunc) entry_point())(method, osr_buf, (intptr_t) this, THREAD),
+      THREAD);
+  }
+
+ private:
+  static void maybe_deoptimize(int deoptimized_frames, TRAPS) {
+    if (deoptimized_frames)
+      CppInterpreter::main_loop(deoptimized_frames - 1, THREAD);
   }
 
  public: