I've checked these all against the Darcs history using a script
(check-copyright, in my misccode collection). Anything Neil or I did as
part of our PhDs is copyright University of Kent; more recent work
belongs to us, as appropriate.
Most of this was a find-and-replace, PolyplateM -> AlloyA. But I also fixed some of the opsets and removed types that were no longer needed, and so on.
The pass was folding the two arrays together, then digging too far into the dimensions of the outer array, rather than looking at the dimensions of the inner array.
This may seem like an odd change, but it simplifies the logic a lot. I kept having problems with passes not operating on externals (e.g. functions-to-procs, adding array sizes, constant folding in array dimensions) and adding a special case every time to also process the externals was getting silly.
Putting the externals in the AST therefore made sense, but I didn't want to just add dummy bodies as this would cause them to throw up errors (e.g. in the type-checking for functions). So I turned the bodies into a Maybe type, and that has worked out well.
I also stopped storing the formals in csExternals (since they are now in csNames, and the tree), which streamlined that nicely, and stopped me having to keep them up to date.
The separately compiled occam PROCs now use #PRAGMA OCCAMEXTERNAL, which also discards the "= number" thing at the end. These PROCs then need to be processed differently when adding on the sizes (C externals have one size per dimension, occam externals have the normal array of sizes).
We also now record which processes were originally at the top-level, and keep their original names (i.e. minus the _u43 suffixes) plus an "occam_" prefix to avoid collisions.
This is quite a big patch, as it reworks a large pass. The three backend passes dealing with sizes stuff have now been merged into one (because the traversal order is important).
Instead of generating sizes arrays by blindly appending "_sizes", we now create nonces and store them in the csArraySizes map in CompState, which is a bit less hacky.
Added to that, we also generate constant-size arrays (e.g. for [8]) -- which are needed in case we pass the array to a PROC that has a flexible dimension -- at the top of the whole program, and use that array for every variable with that size (so if foo and bar have the same size, we use the same sizes array from the top of the program).
Also known as communication semantics, I think. The pass adds an extra channel parameter per mobile (perhaps in future this could be a single extra channel?) that is used to send back the mobile value, and hacked the backend so that the communications to receive these mobiles are done in the right place (after the processes have been run, but before waiting on the barrier for them to complete).
cgtest83 now compiles, runs and passes without a segfault.
This is mostly straightforward: modify the parser to allow direction
decorators in the right places, and extend the type checker to match.
There's some slight awkwardness in that some of the Types functions
have to perform the same checks as the type checker (e.g. directing a
non-channel), so I've tidied up their error messages a bit.
At the backend, I've just added a little pass to strip out all the
DirectedVariables, since the other backend passes don't handle them
gracefully. From the occam/C point of view this is fine, but I'm not
sure if it's going to cause problems for C++.
This also refactors the sizes-array-declaring code, pulling the
declaration of static sizes out to a helper function, and does a
couple of other minor cleanups to match.
All the passes now have their information (name, pre-requisites and post- properties) stored at the point where the pass is declared, which means the pass lists are just a simple list of pass functions.
The main consequence of this change was that the tests had to be changed. Now, instead of taking a "pass applied to data" item (type: PassM b), they take both the pass (type: Pass) and source data (type: b), and apply them later. This was the decision that involved the simplest changes to the existing tests (simply unbracketing the application of the pass to the source). I also had to include a few old-style versions though (testPass', testPassShouldFail') for where the functions were being used to test things that weren't actually passes (mainly StructureOccam).
Fixes#48
NameType is only really needed in the parser, so this takes it out of
NameDef, meaning that later passes defining names no longer need to
set an arbitrary NameType for them. The parser gets slightly more
complicated (because some productions now have to return a SpecType
and a NameType too), but lots of other code gets simpler.
The code that removed free names was the only thing outside the parser
using NameType, and it now makes a more sensible decision based on the
SpecType. Since unscoped names previously didn't have a SpecType at
all, I've added an Unscoped constructor to it and arranged matters
such that unscoped names now get a proper entry in csNames.
Fixes#61.
This makes it possible to mark a slice as not needing runtime
checking, which is immediately useful for _sizes arrays.
This fixes cgtest03, which was previously failing to compile because
the _sizes array for one of the constants in it contained a runtime
check and thus wasn't itself constant. I've added a testcase file for
the relevant bit of code.
