Refactor RegExpStub to check lazily.

R=ulan@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/12210143

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13727 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/jsregexp.cc

@@ -687,6 +687,7 @@ Handle<JSArray> RegExpImpl::SetLastMatchInfo(Handle<JSArray> last_match_info,
                                              Handle<String> subject,
                                              int capture_count,
                                              int32_t* match) {
+  CHECK(last_match_info->HasFastObjectElements());
   int capture_register_count = (capture_count + 1) * 2;
   last_match_info->EnsureSize(capture_register_count + kLastMatchOverhead);
   AssertNoAllocation no_gc;

src/objects.h

@@ -7784,6 +7784,9 @@ class ExternalString: public String {
   static const int kResourceDataOffset = kResourceOffset + kPointerSize;
   static const int kSize = kResourceDataOffset + kPointerSize;
 
+  static const int kMaxShortLength =
+      (kShortSize - SeqString::kHeaderSize) / kCharSize;
+
   // Return whether external string is short (data pointer is not cached).
   inline bool is_short();
 

src/runtime.cc

@@ -1725,7 +1725,6 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_RegExpExec) {
   // length of a string, i.e. it is always a Smi.  We check anyway for security.
   CONVERT_SMI_ARG_CHECKED(index, 2);
   CONVERT_ARG_HANDLE_CHECKED(JSArray, last_match_info, 3);
-  RUNTIME_ASSERT(last_match_info->HasFastObjectElements());
   RUNTIME_ASSERT(index >= 0);
   RUNTIME_ASSERT(index <= subject->length());
   isolate->counters()->regexp_entry_runtime()->Increment();
@@ -3225,8 +3224,6 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_StringReplaceRegExpWithString) {
 
   if (!replacement->IsFlat()) replacement = FlattenGetString(replacement);
 
-  ASSERT(last_match_info->HasFastObjectElements());
-
   if (replacement->length() == 0) {
     if (subject->IsOneByteConvertible()) {
       return StringReplaceRegExpWithEmptyString<SeqOneByteString>(
@@ -3775,7 +3772,6 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_RegExpExecMultiple) {
   CONVERT_ARG_HANDLE_CHECKED(JSArray, last_match_info, 2);
   CONVERT_ARG_HANDLE_CHECKED(JSArray, result_array, 3);
 
-  ASSERT(last_match_info->HasFastObjectElements());
   ASSERT(regexp->GetFlags().is_global());
 
   if (regexp->CaptureCount() == 0) {