[Isolates] Pass current isolate address to the regexp native functions

src/x64/regexp-macro-assembler-x64.cc

Index: src/x64/regexp-macro-assembler-x64.cc
diff --git a/src/x64/regexp-macro-assembler-x64.cc b/src/x64/regexp-macro-assembler-x64.cc
index 7a9fdef4136beaaa3f591ab52ced918c9f6cf8da..37bdd5225d3cc827245d6d88b9474999f1382515 100644
--- a/src/x64/regexp-macro-assembler-x64.cc
+++ b/src/x64/regexp-macro-assembler-x64.cc
@@ -68,6 +68,7 @@ namespace internal {
  *
  * The stack will have the following content, in some order, indexable from the
  * frame pointer (see, e.g., kStackHighEnd):
+ *    - Isolate* isolate     (Address of the current isolate)
  *    - direct_call          (if 1, direct call from JavaScript code, if 0 call
  *                            through the runtime system)
  *    - stack_area_base      (High end of the memory area to use as
@@ -1131,8 +1132,10 @@ static T& frame_entry(Address re_frame, int frame_offset) {
 int RegExpMacroAssemblerX64::CheckStackGuardState(Address* return_address,
                                                   Code* re_code,
                                                   Address re_frame) {
-  if (Isolate::Current()->stack_guard()->IsStackOverflow()) {
-    Isolate::Current()->StackOverflow();
+  Isolate* isolate = frame_entry<Isolate*>(re_frame, kIsolate);
+  ASSERT(isolate == Isolate::Current());
+  if (isolate->stack_guard()->IsStackOverflow()) {
+    isolate->StackOverflow();
     return EXCEPTION;
   }