Don’t get the title wrong, I like GCC, but there are a few things that don’t trigger a warning in GCC, but do on Borland’s, which are quite useful and important.
The main thing I miss is the warning that Borland gives you when a variable is given a value that is never used. As I wrote more than a week ago GCC does not warn you about unused variables if they are assigned a value after they are declared. Which in xine tends to happen quite some times.
This is pretty important because, even if GCC is good enough not to emit the variable if it’s not used, if the assigned value is the return value of a function, the function call is unlikely to be optimised away. Pure and constant functions should be optimised away, but for functions the compiler has no clue about (which is the common status for non-static functions unless you tell it otherwise) the call is still executed, as it might change the global state variables. If the call is expensive, it would be a waste of CPU.
So I first tried ICC, remembering it used to have nicer and stricter warnings than GCC. Unfortunately even after installing it, getting a license key and opening a new shell with the environment set up, I get this:
/usr/include/stdlib.h(140): error: identifier "size_t" is undefined extern size_t __ctype_get_mb_cur_max (void) __THROW __wur;
As you can guess, it’s not very nice that
size_t results undefined, and indeed it can’t even complete the
Then I decided to try Sun’s compiler. I remembered Donnie having an ebuild for
sunstudio on his overlay, so I downloaded that and installed sunstudio. I had to fix a bit the build system of xine because Sun’s compiler was detected only under Solaris for PThread support, while of course you can use Sun’s compiler under Linux too.
After completing the
./configure run properly, I’ve started seeing issues with xine’s code.. well I expected that. Mostly, the short form of the ternary operation (
foo ? : bar, which is equivalent to
foo ? foo : bar but with a single evaluation of foo) is not supported – I suppose it’s a GNU extension – but that’s not difficult to fix by avoiding that form…
The problems started the moment it compiled the first source file for
xine-lib itself (rather than its tools):
c99: Warning: illegal option -fvisibility=hidden "../../../src/xine-engine/xine.c", line 83: internal compiler error: Wasted space c99: acomp failed for ../../../src/xine-engine/xine.c
Now with all the good will I have, what should “Wasted space” mean to me‽
The illegal option is also a nice thing to see, considering that I test that during the
./configure phase, and Sun’s compiler answers me a lot like it works:
configure:49543: checking if compiler supports -fvisibility=hidden configure:49560: sunc99 -c -features=extensions -errwarn=%all -fvisibility=hidden conftest.c >&5 c99: Warning: illegal option -fvisibility=hidden configure:49567: $? = 0 configure:49584: result: yes
Sincerely, I start to think a lot lately when I read about Sun wanting the good of Free Software. I had a few people telling me that xine lacks support for Solaris, Sun Studio compiler, UltraSPARC architecture, … well it’s not like it’s easy to support those, considering that Solaris for x86 is quite slow, and wasn’t working under VirtualBox for a while – it should work now but I haven’t had time to look at it yet, SunStudio for Linux fails, as I just noted, and the only way to get a decent Sun system for a standalone developer is looking and hoping at second hand offers on eBay and similar (a T2 basic server costs about $15K, a bit out of my league, for optimising xine, and as far as I can see all their workstation are now AMD64-based — or x64 as they call it, but I hate that market name as it really means nothing).
Maybe they are just interested in enterprise Free Software, but still… I sincerely think they have the right cards to make some difference, but I can’t see much Free Software development, beside the usual enterprise one, going on with Sun systems in the next future. Which is a bit sad considering I’ve seen my Ultra5 outpowering an Athlon almost twice its frequency…