Parrot Cage Cleaners high-level goals
Smoke testing on many platforms with many compilers
The more platforms we have, the more likely we are to find portability problems. Parrot has to be the most portable thing we've created.
More platforms also means more compilers. Maybe your DEC compiler is more picky than gcc, and spews more warnings. Good! More opportunities for cleaning!
Compiler pickiness
Use as many compiler warnings as we possibly can. The more warnings we enable, the less likely something will pass the watchful eye of the compiler.
Note that warnings may not just be -W flags. Some warnings in gcc only show up when optimization is enabled.
splint
Splint (http://www.splint.org) is a very very picky lint tool, and setup and configuration is a pain. Andy has tried to get Perl 5 running under it nicely, but has met with limited success. Maybe the Parrot will be nicer.
Create a make target for splint.
Make splint run against all the *.c files.
Make a reasonable set of rules for splint.
splint spews many many errors by default. Take a look at the Makefile that perl5 has for the start of some rules that Andy worked on for the perl5 code.
Solaris lint
Sun has made its dev tools freely available at http://developers.sun.com/prodtech/cc/. Its lint is the best one out there, except from Gimpel's FlexeLint (http://www.gimpel.com/html/flex.htm) which costs many dollars.
Create a make target for lint.
Make lint run against all the *.c files.
Make a reasonable set of rules for lint.
Andy has a pretty decent set of rules for perl5's code in that project's Makefile. Take a look at those for a start.
Enforcing coding standards, naming conventions, etc
Automatic standards checking
The docs in filename here explains what our code should look like. Write something that automatically validates it in a .t file.
constcheckingDeclaring variables as
constwherever possible lets the compiler do lots of checking that wouldn't normally be possible. Walk the source code adding theconstqualifier wherever possible. The biggest bang is always in passing pointers into functions.constexplainingThe description above is pretty sparse. A good description of
constand its benefit would be helpful for newcomers.
Decreasing the amount of repeated code
PMD (http://pmd.sourceforge.net/) has been used on C code, even though it's a Java tool. It looks for repeated strings of tokens that are candidates for either functions or macros.
Automated source macros
Perl5 has a lot of good source management techniques that we can use.
Standardizing on "interp"
Standarizing on "interp" or maybe even "intr" as the interpreter variable, for brevity & consistency
Macro for interp argument
A macro for declaring the interpreter argument, and maybe a macro for passing it
BTW, our Perl experience teaches us that somebody is going to want to make the interpreter a C++ object for Windows environments, and it wouldn't hurt to make that possible, or at least work in that direction, as long as clarity doesn't suffer.
Redo CONTEXT(interp->ctx)->foo
Eliminating the
CONTEXT(interp->ctx)->foousage in favor of the much simplerinterp->ctx->foo, or similar simplification.Parrot_xxx macros
Automated processing that would make a macro to let us write
somefunc(interp,a,b,c)while the linkage is
Parrot_somefunc(interp,a,b,c)for namespace cleanup. This is straight out of embed.fnc and proto.h in Perl5.
Automated generation of C headers
This has started significantly with the headerizer.pl program. Right now, it extracts the function headers correctly, but now I have to have it create the .h files.
Improve low-level code quality
Fix symbol table namespace pollution
Extern functions and variables must have names that begin with
Parrot.Fix non-symbol-table namespace pollution in public headers
Public headers are the ones in
include/parrotdirectory. These are included by embedders and extenders. They must not declare or define any symbol that isn't clearly Parrot-specific. Prefixing symbols withParrotorPARROTis the easiest & safest way, but it can lead to a lot of verbosity, so Chip is willing to entertain exceptions or new conventions.It's OK for public headers might have non-public parts protected with
#ifdef PARROT_IN_CORE. Those non-public parts might #define shorter versions of the public symbols, e.g.#define foo Parrot_foo.
Creating automated code checking tools
Documenting function behavior and structure members
Developing coverage tools
Automatically running the coverage tools
Run on many different C compilers
Most of Andy's work right now is with GCC 4.2 on Linux. We need many more.
Run under valgrind
Valgrind (http://valgrind.org/) is a profiler/debugger most notable for the way it magically monitors memory accesses and management.
Make a "make valgrind" target
Run under Coverity Prevent
Coverity already runs Prevent on the Perl 5 source. Let's get Parrot running under it, too. http://scan.coverity.com/
IMCC cleanup
From #parrot:
vsoni: there seems to be some dead code/feature....I had a chat
with leo and I am going to send and email to p6i for deprecation
of certain old featuresHelp other contributors hack their patches into Parrot-style industrial-strength C code.
From chip's comment at http://www.oreillynet.com/onlamp/blog/2006/07/calling_for_parrot_janitors.html
We've just had contributed an improved register allocation
implementation, but since the contributor is new to Parrot,
there are some style and coding standards issues that need to
be worked out. It'd be great if a Cage Cleaner could step up
and help our new contributor bang the code into Parrotish form.Fix usage of deprecated features
Clean up skipped tests
Parrot has too many skipped tests. Pick a test file with a skipped test, disable the skip() line, then make it pass. The Parrot code may not compile, or you may have to modify it to bring it up to date. The test may not even be useful anymore; we won't know until you try.
If you can make it pass, great!
If you can make it run, great! Make it a TODO test instead.
If neither, please report your findings so that everyone can decide what to do.
See Also
Also look at docs/BROKEN.pod, docs/ROADMAP.pod, and the list of Cage items on RT: http://xrl.us/owsd (Link to rt.perl.org)