Hey kjs, No problem, since I helped to get the poke_caller test to pass I figured I could help out.
On Jun 6, 2012, at 12:35 PM, kjstol <[email protected]> wrote: > hi Nate, > > thanks very much for your analysis. Much appreciated. > > On Wed, Jun 6, 2012 at 12:24 PM, Nathan Brown <[email protected]> wrote: >> Hey kjs, >> >> So after a quick look last night, I've concluded that we should try to >> implement the chunk_map portion of the m0 spec because the poke_caller >> test looks like it's using it but in reality it isn't. Lines 271-274 >> (https://github.com/parrot/parrot/blob/m0/t/m0/integration/m0_poke_caller.m0#L271) >> in the test are misleading, the original code is: >> >> # S3 is the parent call frame's CHUNK >> set_imm I3, 0, CHUNK >> deref I3, CONSTS, I3 >> goto_chunk I3, I4, x >> >> But this only works because CHUNK = 5 and the 5th item in the callee >> const table is "&caller". > > Does this mean it is a coincidence/accident that the example > (poke_caller) is actually working? Just because CHUNK has the value 5, > and the caller happens to be at the 5th position in the callee's CONST > table? Yes, I didn't notice this coincidence before. I was initially just working to get the test passing and removing the workarounds that were blocking me. Somehow I didn't notice this issue. > > I think the code should be: >> >> # I3 is the parent call frame's CHUNK >> set_imm I3, 0, CHUNK >> deref I3, PCF, I3 >> goto_chunk I3, I4, x >> >> But for this to work, we need to make the CHUNK register (see >> https://github.com/parrot/parrot/blob/m0/docs/pdds/draft/pdd32_m0.pod#register-types-and-call-frame-structure) >> and CHUNKS, CHUNK_INFO and CHUNK_MAP interpereter data (see >> https://github.com/parrot/parrot/blob/m0/docs/pdds/draft/pdd32_m0.pod#interpreter-data) >> get populated correctly and used throughout m0. > > Do you know whether this has been implemented in M0? It had not in c. I think it has in perl. >> >> The spec states that CHUNK register should be "the index of the >> currently-executing chunk." The spec also says we should be using >> chunk indices and not names when we use the goto_chunk op. I believe >> that implementing this will mean m1 won't have to store the current >> chunk's name in its const table. >> >> If no one beats me to it, I'll take a swing at this stuff this weekend. > > Great! > cheers, > kjs > >> >> -Nate >> >> On Jun 5, 2012, at 8:12 PM, Nathan Brown <[email protected]> wrote: >> >>> Hi kjs, >>> >>> Nothing stands out to me immediately, but I'll try to get m1 working >>> and look at it. From the code excerpts, it looks like it works, but >>> I'd like to see all the m0 code and try to figure it out. >>> >>> I've been away for a bit, but I'm almost back and would love to help >>> getting m0 and m1 to work better together. >>> >>> Nate >>> >>> On Tue, Jun 5, 2012 at 5:18 PM, kjstol <[email protected]> wrote: >>>> hi Nate, >>>> >>>> thanks for your reply. >>>> I've actually stolen most of the code that is generated by M1 from >>>> that particular example. If you look at that example, you'll see that >>>> the callee chunk has the caller's name in its constants segment, which >>>> is loaded at the end. >>>> >>>> When M1 generates the following code (as it does now): >>>> >>>> set_imm I2, 0, PCF >>>> deref P0, CF, I2 >>>> set_imm I3, 0, RETPC >>>> deref I3, P0, I3 >>>> set_imm I2, 0, 2 >>>> deref I2, CONSTS, I2 >>>> goto_chunk I2, I3, x >>>> >>>> and you add "&main" at index 2 of the const segment, then it works. >>>> However, when M1 is changed to access the parent's CF instead: >>>> >>>> set_imm I2, 0, PCF >>>> deref P0, CF, I2 >>>> set_imm I3, 0, RETPC >>>> deref I3, P0, I3 >>>> set_imm I5, 0, CONSTS ## get index of CONSTS >>>> deref P1, P0, I5 ## get CONSTS thingy from parent CF (in P0) >>>> set_imm I6, 0, 0 ## load "0" >>>> deref I4, P1, I6 ## get the name of the calling function, in >>>> P1, >>>> which is the parent's CF's CONST segment. The name is ALWAYS stored at >>>> index 0. >>>> goto_chunk I4, I3, x >>>> >>>> With this code, the function doesn't return. >>>> Perhaps I'm overlooking something...? >>>> >>>> kjs >>>> >>>> >>>> On Tue, Jun 5, 2012 at 4:16 PM, Nathan Brown <[email protected]> wrote: >>>>> Hello kjs, >>>>> >>>>> m0 actually already has a mechanism for tracking the caller, it's the >>>>> parent (or previous) call frame PCF register. Since functions and call >>>>> frames are equivalent in M0, setting the parent/previous call frame >>>>> register in the child call frame to the address of the current call frame >>>>> prior to invoking the child call frame will give you knowledge of the >>>>> caller. This is the way that the poke_caller test in the m0 test suite >>>>> does it. >>>>> >>>>> Hope that helps, >>>>> Nate >>>>> >>>>> On Jun 5, 2012, at 8:35 AM, kjstol <[email protected]> wrote: >>>>> >>>>>> hi there, >>>>>> >>>>>> M1's getting more complete by the day. Function invocations and >>>>>> returns are working, _almost_ (making a few minor manual fixes in the >>>>>> generated M0 code makes it work). The problem is that the called >>>>>> function needs to know about which function it called, so its caller. >>>>>> This is a problem, because obviously, any function can call any other >>>>>> function. In particular, for a function to return, it needs to know >>>>>> the name of the caller, which it takes from the CONSTS segment. >>>>>> >>>>>> One way to do this is of course to pass the name of the caller. I >>>>>> suspect this has something to do with continuation-passing style, >>>>>> where you pass a continuation chunk, which is then invoked in order to >>>>>> return. This will have to be figured out. So, please consider this >>>>>> email as a request for further spec. of M0 :-) >>>>>> >>>>>> Meanwhile, I'll continue with more basic stuff; enumerations, variable >>>>>> scoping, and perhaps namespaces are next. Suggestions and feedback and >>>>>> requests for features are welcome. >>>>>> >>>>>> Comments welcome, >>>>>> kjs >>>>>> >>>>>> >>>>>> >>>>>> On Sun, May 20, 2012 at 2:59 PM, kjstol <[email protected]> wrote: >>>>>>> hi there, >>>>>>> >>>>>>> Attached a new version; this does some basic code generation. I'm not >>>>>>> really familiar with M0 instructions yet, but I made a few guesses. >>>>>>> Expression handling seems to work well. >>>>>>> >>>>>>> There's many todos', but it's quite close to generating valid M0 >>>>>>> (acceptable by the perl assembler script). Conditional and iteration >>>>>>> statements are not done yet (needs handling of labels etc.) but could >>>>>>> easily be added. >>>>>>> >>>>>>> I'm not entirely sure what kind of syntax and functionality is needed >>>>>>> at the M1 level. Is the idea to write PMCs at this level? In that case >>>>>>> you'd want to have a "PMC" keyword I think, and allow writing member >>>>>>> functions in such a PMC. Also, allocating memory could be built-in, >>>>>>> rather than copying C's malloc and free function implementations. >>>>>>> Also, do exceptions live at this level? In that case you'd probably >>>>>>> want some kind of "try/catch" or alternative notation. >>>>>>> >>>>>>> to run: >>>>>>> ==== >>>>>>> unzip the zip file >>>>>>> cd m1 >>>>>>> make >>>>>>> ./m1 t2.m1 >>>>>>> >>>>>>> Feedback would be appreciated. >>>>>>> thanks >>>>>>> kjs >>>>>>> >>>>>>> On Sun, May 20, 2012 at 3:06 AM, kjstol <[email protected]> wrote: >>>>>>>> hi! >>>>>>>> >>>>>>>> On Sun, May 20, 2012 at 2:55 AM, Vasily Chekalkin <[email protected]> >>>>>>>> wrote: >>>>>>>>> Hello. >>>>>>>>> >>>>>>>>> Welcome back :) >>>>>>>> >>>>>>>> thanks :-) >>>>>>>> >>>>>>>>> >>>>>>>>> For the record, current nqp-rx based ops compiler does parse subset of >>>>>>>>> C already. In opsc_llvm branch it does parse even more. I would >>>>>>>>> suggest to join efforts in defining "C subset" which we are going to >>>>>>>>> use as m1 ops language. >>>>>>>>> >>>>>>>>> Most problematic parts iirc was: >>>>>>>>> 1. Macros. C macros are pure evil. If we are going to support >>>>>>>>> free-defined C macros it will require a lot of work. Limiting them to >>>>>>>>> VTABLE macros will reduce this issue to trivial. >>>>>>>>> 2. Ambiguous casting. >>>>>>>>> 3. Implicit string concatenation. >>>>>>>> >>>>>>>> Thanks for sharing. I can see how scattered efforts are not helpful. >>>>>>>> >>>>>>>> It wasn't so much an effort to implement parts of C per se, more that >>>>>>>> it's inspired by C: it's easy to read, easy to learn, and easy to >>>>>>>> implement so far. Also, my efforts so far were an expression of my >>>>>>>> self indulgence in some good hacking sessions, which I hadn't done for >>>>>>>> a long time. It's been fun :-) >>>>>>>> >>>>>>>> In my opinion, for M1, we shouldn't strive for a subset of C per se. >>>>>>>> There's many things wrong with C, and those things cause a lot of pain >>>>>>>> and bugs. If there's going to be a language M1 or Lorito to implement >>>>>>>> most of parrot (incl PMCs) it would be a good idea to define a >>>>>>>> language that prevents many of those bugs, to create a language that's >>>>>>>> really stable, clearly defined, and so on, and that forbids bad >>>>>>>> constructs. For instance, no goto statement! (I'm even no fan of break >>>>>>>> and continue statements). C's preprocessor is a cheap way of doing >>>>>>>> modules properly, but it's kindof awful. There's better ways I'm sure >>>>>>>> to support multi-file programs. I think it would be a good idea to >>>>>>>> think well about how to encourage sound programming practices (C >>>>>>>> doesn't really), and implement a language that does that well, while >>>>>>>> still being easy to learn by C programmers. >>>>>>>> >>>>>>>> Meanwhile, my goal was to (1) indulge in my need for some hacking >>>>>>>> creativity, and (2) create a clean and simple language implementation >>>>>>>> that targets M0. Consider it a prototyping effort to identify gaps in >>>>>>>> M0 and see how far we can get with little effort. >>>>>>>> >>>>>>>> cheers >>>>>>>> kjs >>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> Bacek >>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> Vasily >>>>>>>>> >>>>>>>>> On Sat, May 19, 2012 at 6:15 AM, kjstol <[email protected]> wrote: >>>>>>>>>> hi there, >>>>>>>>>> >>>>>>>>>> I've indulged in some hacking time, and implemented a simple subset >>>>>>>>>> of C. >>>>>>>>>> Attached is a zip file, just type "make" and it should work (assuming >>>>>>>>>> you have bison and flex). >>>>>>>>>> >>>>>>>>>> What it currently does, it generates the parsed code from the AST >>>>>>>>>> (mostly). >>>>>>>>>> Not everything of the language is supported yet (e.g., parameters >>>>>>>>>> etc.) The parser would have to be fixed a bit, it has some known >>>>>>>>>> limitations. >>>>>>>>>> >>>>>>>>>> The idea next is to implement a simple code generator to generate the >>>>>>>>>> M0 ops that have been spec'ed so far. >>>>>>>>>> There are many todos (e.g, thread-safety of the compiler), >>>>>>>>>> register-allocator, etc.) most of which would be easy to implement. >>>>>>>>>> For now, the focus would be on a simple and clean language >>>>>>>>>> implementation that generate M0. >>>>>>>>>> >>>>>>>>>> Comments welcome, >>>>>>>>>> kjs >>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> http://lists.parrot.org/mailman/listinfo/parrot-dev >>>>>>>>>> >>>>>> _______________________________________________ >>>>>> http://lists.parrot.org/mailman/listinfo/parrot-dev _______________________________________________ http://lists.parrot.org/mailman/listinfo/parrot-dev
