On 8/10/06, Chip Salzenberg <[EMAIL PROTECTED]> wrote:
I appreciate the quality of the stm code in general. You're being careful,
you know what you're doing with C, and you're good at creating abstractions.
I hope when STM is done[*] you'll keep hacking on Parrot.
[*] As if it will ever be really done.
"No work of art is ever finished, only abandoned."
Here are my comments. Once these issues and/or questions are addressed
and/or diposed of, we can merge the state-of-stm onto the trunk. Please
correct me wherever I've misunderstood what you're doing.
POSSIBLE BUGS
* START_WRITE_HLL params vs. usage
+#define START_WRITE_HLL(interpreter, hll_info) \
+ do { \
+ if (PMC_sync(interpreter->HLL_info)) { \
+ hll_info = interpreter->HLL_info = \
+ Parrot_clone(interpreter, interpreter->HLL_info); \
+ if (PMC_sync(interpreter->HLL_info)) { \
+ mem_internal_free(PMC_sync(interpreter->HLL_info)); \
+ } \
+ } \
+ } while (0)
But then:
+ START_WRITE_HLL(interpreter, interpreter->HLL_info)
That expansion, which is in part:
interpreter->HLL_info = interpreter->HLL_info = Parrot_clone(interpreter,
interpreter->HLL_info);
mem_internal_free(PMC_sync(interpreter->HLL_info));
Looks odd or even broken, offhand. Am I missing something?
I think it was just odd but violated what I had intended for that
macro. I've changed the use of the macro.
* enum trailing commas are not standard
C89 doesn't allow enum lists to end with a comma. PITA, I know, but we
can't require C99 yet. So e.g. 'thread_state_enum' needs a comma removed.
Fixed.
QUESTIONS/REQUESTS
* You're defining a heck of a lot of macros. Is there any set of them that
can be marked as private (to the STM implementation), e.g. with a leading
single underscore? Say, if the ATOMIC_INT_CAS macro is only used by other
macros and isn't part of the supported interface, then it could be renamed
to _ATOMIC_INT_CAS. This will prevent the abstraction from leaking.
* It's surely a mean trick on the poor user/programmer to have
Parrot_atomic_int actually hold a long. :-, Any reason not to use int?
Or do you want Parrot_atomic_long?
I changed the name to Parrot_atomic_integer; I don't want to imply
that it's going to be the
same width as any particular built-in type or any particular
Parrot-supplied type. I haven't
changed ATOMIC_INT_* -> ATOMIC_INTEGER_*, however, as I feel those
macro names are long enough (especially with PARROT_ added, see below)
and as I abbreviated 'pointer' too. (If you disagree, I'll change
those, too.)
* Is there any need/use for multiple integral atomic types, like an
unsigned or a UINTVAL or something? (I expect the answer is "no".)
No.
* Could *_{READ,WRITE}_HLL be named something like *_{READ,WRITE}_HLL_INFO,
assuming they need to be macros at all? An HLL is an abstraction that
currently doesn't have a single concrete representation.
Done.
* I see that Parrot_get_HLL_namespace() is now deferring namespace creation.
That could perhaps be problematic. We've told users that
get_root_namespace ['your_own_hll'; 'x']
and
get_hll_namespace ['x']
have identical results. So, what's the payoff for this delayed creation?
Mainly my coding convenience. I've undelayed the creation.
* Does your ops.num renumber ops, or is diff just getting confused by
whitespace?
If the former, what's up?
I apparently renumbered ops by mistake (I guess I shouldn't have
assumed that dev/tools/ops_renum.mak would DTRT). Fixed by manually
adding my new ops to the end of the file from trunk.
CODING STANDARD^WWHIM ISSUES
I do need to update pdd07. In the meantime, here are some coding standard
issues I'd appreciate if you'd address. For some of them you're going to be
setting the new standard for the rest of the code, but such is the fate of
code reviewed the guy who's writing the new spec. :-,
* Out of all the macros you're defining, will any of them be ever needed by
users of the Parrot extension or embedding interfaces? If so, their full
official names will have to start with "PARROT_". But when compiling
Parrot, it's OK to define non-PARROT_-prefix versions as aliases.
Full names changed along with all usages (instead of defining aliases).
[snip]
* macro args & protection
Most of your code is really good & careful with macro behaviors.
Just a couple exceptions:
+#define START_WRITE_HLL(interpreter, hll_info) \
+ do { \
+ if (PMC_sync(interpreter->HLL_info)) { \
+ hll_info = interpreter->HLL_info = \
+ Parrot_clone(interpreter, interpreter->HLL_info); \
+ if (PMC_sync(interpreter->HLL_info)) { \
+ mem_internal_free(PMC_sync(interpreter->HLL_info)); \
+ } \
+ } \
+ } while (0)
Macro arguments should be parenthesized when used, and it helps to name
them in all caps so as to distinguish them from the normal names ref'd in
the macro body.
Similarly, when you're not using "do {} while (0)", the macro expansion
should be parenthesized if it contains an exposed operator. For example,
this:
+# define ATOMIC_INT_INC(result, a) result = ++(a).val
should be paren'd:
+# define ATOMIC_INT_INC(result, a) ((result) = ++(a).val)
Extra parenthesis have been added to (I think) all the ATOMIC_* macros, and to
START_WRITE_HLL(_INFO). I'll try to read through the diff and see if I
missed anything.
* useless curlies
- if (PMC_IS_NULL(type_hash))
+ if (PMC_IS_NULL(type_hash)) {
return core_type;
+ }
hash = PMC_struct_val(type_hash);
- if (!hash->entries)
+ if (!hash->entries) {
return core_type;
+ }
Something I'm hoping to stamp out is the use of curlies for all if/else
clauses, which makes code taller without making it substantially clearer.
I'd appreciate if you'd use a no-curlies-when-possible style.
OTOH, if you don't want to do this right away, I'd be OK with a merge
first, and fixing the curlies later.
OTGH, the project needs automated filters for more coding standards,
including one that that notes (and optionally kills) the excess curlies.
I am used to the other style; I'll try to do a pass over the diff and
change them though I suspect I'll miss a few.
* params of type "const Parrot_Interp"
-void pt_thread_prepare_for_run(Parrot_Interp d, Parrot_Interp s);
+void pt_thread_prepare_for_run(Parrot_Interp d, const Parrot_Interp s);
What's the purpose of this? It doesn't protect *s from changes. [time
passes] I now see that some of the existing functions already have this
construct. Perhaps you were just imitating them?
Correct. I removed (most of?) those extraneous uses of const.
-- Charles
