Storing the lcname of symbols

Hi Levi Morrison, > > Hello! > > > > Most of PHP's symbols are case insensitive. This means extensions that > > need to do things with function and method names end up lowercasing > > and hashing the lowercased names, often having to do more memory > > allocations too. Since case insensitive symbols is language dictated > > behavior, it makes sense to expose the correctly cased symbols to > > extensions. In PHP 8.0 (and possibly older, I did not check), the > > engine is already interning the lowercased name of user defined > > functions; it's just not made available to extensions. > > > > In my ideal world, we'd actually switch all symbols to be case > > sensitive. However, that won't be happening for PHP 8 due to BC. > > > > So, instead, I propose adding an `.lcname` member (or some other name > > indicating it's been normalized to the preferred PHP case) to at least > > zend_op_array and zend_class_entry, but preferably for internal > > functions too. Note that many internal functions will already be > > lowercase, so the data can be shared. > > > > I could make this change in the main engine, but I strongly suspect it > > will not play correctly with opcache. > > > > -- > > PHP Internals - PHP Runtime Development Mailing List > > To unsubscribe, visit: https://www.php.net/unsub.php > > I just realized I didn't ask any specific questions. Oops: > >  1. Can anyone think of issues except increased memory due to > increasing the size of the struct? Since the strings were previously > interned, I don't think the strings themselves will have much effect > on memory usage (but we can measure this). >  2. Anyone else who thinks this would be useful? I don't have a personal use case for this and no common operations come to mind but could be persuaded. The lack of examples or might be why there's been no response. I assume the overhead is probably negligible for classes, and larger for functions. What fields of zend_op_array did you mean? What parts of the engine or extensions would use the lowercase string? I see a few places it's used for compilation in php-src itself but nothing that seems performance critical. What are examples of functionality/functions of extensions that you expect would see a performance improvement? Why would they need to convert the strings to lowercase rather than use the casing of the declaration (e.g. using "memcached" instead of "Memcached" in "class Memcached{...}") E.g. if something had already looked up the `zend_class_entry *ce` for a class name, than `ce->name` would be a string (and a unique pointer) such as "Memcached" that uniquely identifies that class's name (unless the code is unexpectedly redeployed later with different casing) - They're still case sensitive in some ways, e.g. the composer autoloader is case sensitive - Changing case should be rare Regards, Tyson