hi Nate, On Wed, Jun 6, 2012 at 5:51 PM, Nathan Brown <[email protected]> wrote: > 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.
Good to know :-) (and amazing in a sense!) > > > >> >> 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. Ah yes, I'm just scrolling back the IRC logs from yesterday. I saw the link with the todo for the C impl. I had implemented a hashtable for PIRC, the code is available at: https://github.com/parrot/pirc/blob/master/src/pirsymbol.c Probably the only thing that can be copied from that is the hash algorithm. (I believe I took that from the dragon book IIRC). The rest of handling buckets and linking symbols is probably easier to write from scratch. I will also need a hashtable for M1. Perhaps we can write a single hashtable that is reusable. However, getting it to work first is more important. Refactoring can be done later. kjs > >>> >>> 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
