GDB: format output for class entries and class constants

[DanielEScherzer]

For zend_string pointers in class entries, show the string contents (if not NULL).

For class constants, the ce (class entry pointer) field is shown with the name of the class, and the doc_comment field is shown with the string ontents if possible.

[iluuu1994]

For class entries, for null pointers replace 0x0 with NULL for clarity.

Is this really necessary? NULL is literally just # define NULL ((void*)0) in C.

For class constants, the ce (class entry pointer) field is shown with the name of the class, the doc_comment field is shown with the string contents if possible, and NULL if not

Displaying the name directly does seem useful, but isn't it possible to solve this more generically by creating a pretty-printer that supports zend_string?

/cc @arnaud-lb

[arnaud-lb]

For class entries, for null pointers replace 0x0 with NULL for clarity.

Is this really necessary? NULL is literally just # define NULL ((void*)0) in C.

I also think that 0x0 is fine, as it's usual in gdb

For class constants, the ce (class entry pointer) field is shown with the name of the class, the doc_comment field is shown with the string contents if possible, and NULL if not

Displaying the name directly does seem useful, but isn't it possible to solve this more generically by creating a pretty-printer that supports zend_string?

There is a zend_string pretty-printer, but not a zend_string* one:

(gdb) p ce.name
$1 = (zend_string *) 0x125e900
(gdb) p *ce.name
$2 = "ReflectionClass" = {gc = {refcount = 617, u = {type_info = 502}}, h = 12675994317140297638, len = 15, val = "ReflectionClass"}

We could have a zend_string* pretty-printer, but it should not hide the pointer type and address, as these are useful information. I would suggest to print something like this (type, address, string, but not the struct contents) :

(zend_string *) 0x125e900 "ReflectionClass"

[iluuu1994]

Some infos are still useful, i.e. whether the string is interned, persistent, etc. Maybe also print that?

[arnaud-lb]

That would clutter the output, especially in print pretty off mode as everything is on the same line. These information can be easily printed by dereferencing the pointer.

If we have

(gdb) p *ce
$3 = {
  type = 1 '\001',
  name = (zend_string*) 0x125e8f0 "ReflectionClass"
  ...
}

We can easily inspect the name with

(gdb) p *(zend_string*) 0x125e8f0

or

(gdb) p *ce.name

[DanielEScherzer]

We could have a zend_string* pretty-printer, but it should not hide the pointer type and address, as these are useful information. I would suggest to print something like this (type, address, string, but not the struct contents) :

I spent a while trying to get a pointer printer to work and couldn't get GDB to apply it when looking at pointers, but if you know how to do this I agree that it would be nice to have

I also think that 0x0 is fine, as it's usual in gdb

Removed the extra NULL handling

[arnaud-lb]

I spent a while trying to get a pointer printer to work and couldn't get GDB to apply it when looking at pointers, but if you know how to do this I agree that it would be nice to have

My bad, tried it too and I don't think there is a way to pretty print pointers after all

[arnaud-lb]

Thank you @DanielEScherzer!