Support for return-address rewriting profilers.

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 524fcb2b464db14f49786988be29d0818e7a0bba..792f9ed415dd4098cbb7a1af517cd1c67f247acd 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -2858,6 +2858,20 @@ typedef bool (*EntropySource)(unsigned char* buffer, size_t length);
 
 
 /**
+ * ReturnAddressLocationResolver is used as a callback function when v8 is
+ * resolving the location of a return address on the stack. Profilers that
+ * change the return address on the stack can use this to resolve the stack
+ * location to whereever the profiler stashed the original return address.
+ * When invoked, return_addr_location will point to a location on stack where
+ * a machine return address resides, this function should return either the
+ * same pointer, or a pointer to the profiler's copy of the original return
+ * address.
+ */
+typedef uintptr_t (*ReturnAddressLocationResolver)(
+    uintptr_t return_addr_location);
+
+
+/**
  * Interface for iterating though all external resources in the heap.
  */
 class V8EXPORT ExternalResourceVisitor {  // NOLINT
@@ -3111,6 +3125,13 @@ class V8EXPORT V8 {
   static void SetEntropySource(EntropySource source);
 
   /**
+   * Allows the host application to provide a callback that allows v8 to
+   * cooperate with a profiler that rewrites return addresses on stack.
+   */
+  static void SetReturnAddressLocationResolver(
+      ReturnAddressLocationResolver return_address_resolver);
+
+  /**
    * Adjusts the amount of registered external memory.  Used to give
    * V8 an indication of the amount of externally allocated memory
    * that is kept alive by JavaScript objects.  V8 uses this to decide