Shave .2% on PLT by removing bogus strcmp.

[Eric Seidel (no email)]

For whatever reason we had a completely bogus strcmp in HTMLTokenizer which accounted for .2% of all time spent in the PLT (on my MBP):

@@ -901,7 +900,7 @@
                     ptr[--len] = '\0';
 
                 // Now that we've shaved off any invalid / that might have followed the name), make the tag.
-                if (ptr[0] != '!' && strcmp(ptr, "!doctype") != 0) {
+                if (ptr[0] != '!') { // make sure it's not a !DOCTYPE
                     currToken.tagName = AtomicString(ptr);
                     currToken.beginTag = beginTag;
                 }

[Eric Seidel (no email)]

Created attachment 7255 [details]
Remove bogus strcmp to save on plt

[Geoffrey Garen]

Can't "!" also be present for comment elements?

[Darin Adler]

Comment on attachment 7255 [details]
Remove bogus strcmp to save on plt

I think the right change is to change the && to a ||. We're supposed to allow tags like <!custom> I believe.

[Eric Seidel (no email)]

I had considered the ||, but hyatt and I couldn't think of any valid use case for !tagname.  I'll change it to or and add a test case for parsing a <!foo></!foo> tag.

[Darin Adler]

(In reply to comment #4)
> I had considered the ||, but hyatt and I couldn't think of any valid use case
> for !tagname.  I'll change it to or and add a test case for parsing a
> <!foo></!foo> tag.

If we're going to disallow anything starting with "!" (and Dave is definitely an authority on making that call), we should both have tests and also change the comment. I think we can do better than a comment that specifically mentions DOCTYPE and code that checks only for "!".