[regexp] Remove remainder of native RegExpExecStub

src/regexp/regexp-macro-assembler.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/regexp/regexp-macro-assembler.h"
 
 #include "src/assembler.h"
 #include "src/isolate-inl.h"
 #include "src/regexp/regexp-stack.h"
 #include "src/simulator.h"
@@ skipping 152 matching lines @@
   DCHECK(re_code->instruction_start() <= *return_address);
   DCHECK(*return_address <= re_code->instruction_end());
   int return_value = 0;
   // Prepare for possible GC.
   HandleScope handles(isolate);
   Handle<Code> code_handle(re_code);
   Handle<String> subject_handle(*subject);
   bool is_one_byte = subject_handle->IsOneByteRepresentationUnderneath();
 
   StackLimitCheck check(isolate);
-  if (check.JsHasOverflowed()) {
+  bool js_has_overflowed = check.JsHasOverflowed();
+
+  if (is_direct_call) {
+    // Direct calls from JavaScript can be interrupted in two ways:
+    // 1. A real stack overflow, in which case we let the caller throw the
+    //    exception.
+    // 2. The stack guard was used to interrupt execution for another purpose,
+    //    forcing the call through the runtime system.
+    return_value = js_has_overflowed ? EXCEPTION : RETRY;
+  } else if (js_has_overflowed) {
     isolate->StackOverflow();
     return_value = EXCEPTION;
-  } else if (is_direct_call) {
-    // If not real stack overflow the stack guard was used to interrupt
-    // execution for another purpose.  If this is a direct call from JavaScript
-    // retry the RegExp forcing the call through the runtime system.
-    // Currently the direct call cannot handle a GC.
-    return_value = RETRY;
   } else {
     Object* result = isolate->stack_guard()->HandleInterrupts();
     if (result->IsException(isolate)) return_value = EXCEPTION;
   }
 
   DisallowHeapAllocation no_gc;
 
   if (*code_handle != re_code) {  // Return address no longer valid
     intptr_t delta = code_handle->address() - re_code->address();
     // Overwrite the return address on the stack.
@@ skipping 162 matching lines @@
   }
   *stack_base = new_stack_base;
   intptr_t stack_content_size = old_stack_base - stack_pointer;
   return new_stack_base - stack_content_size;
 }
 
 #endif  // V8_INTERPRETED_REGEXP
 
 }  // namespace internal
 }  // namespace v8