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++.
I'm pretty sure this test used to fail and got fixed, but I think the
test was fixed to match the incorrect code rather than the other way
around. What it's testing is the abbreviation of a channel end as an
identically-typed channel end, which (since they're both pointers)
should look something like:
Channel *c;
Channel *d = c;
Instead it was generating "d = &c", which broke cgtest87.
The change made to GenerateC to fix this feels a bit awkward to me --
it's very simple, but it's yet another special case in genVariableAM.
All of the genVariable code could really use reworking (again),
perhaps to use some internal representation of the C expression...
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.
This patch hides all the old typeOfExpression, typeOfName, typeOfVariable, etc, and unifies them into a single type-class with an "astTypeOf" function. The type-class is currently named Typed, but that can easily be changed (it's only explicitly referred to in the Types module). The patch is essentially the type-class with a giant find-and-replace on the other modules.
In particular, evalSimpleLiteral is now much nicer, and the error
messages should be a bit more comprehensible.
The signed types previously used a different version of fromRead that
passed an extra argument that it then didn't use; I've switched back to
the old version now, since it appears not to need it any more.
It's redundant, since you can always compute them from the variable, and it
makes the code that deals with actuals rather cleaner.
On the other hand, it slightly complicates some of the tests, because any names
you use in an Actual need to be defined...
This touches an awful lot of code, but cgtest07/17 (arrays and retyping) pass.
This is useful because there are going to be places in the future where we'll
want to represent dimensions that are known at runtime but not at compile time
-- for example, mobile allocations, or dynamically-sized arrays. It simplifies
the code in a number of places.
However, we do now need to be careful that expressions containing variables do
not leak into the State, since they won't be affected by later passes.
Two caveats (marked as FIXMEs in the source):
- Retypes checking in the occam parser is disabled, since the plan is to move
it out to a pass anyway.
- There's some (now very obvious) duplication, particularly in the backend, of
bits of code that construct expressions for the total size of an array
(either in bytes or elements); this should be moved to a couple of helper
functions that everything can use.
Procs that are in csParProcs are now generated with the correct calling
convention directly, rather than having a second wrapper function generated
around them.
All it did was to make a list of the Procs generated by parsToProcs, so
parsToProcs may as well just do the same job itself.
The reason I'd made it a separate pass originally was that I wanted to
optimise out the wrapper when the child of a Par was already a ProcCall.
That optimisation isn't going to be possible any more with the new CCSP,
since wrappers have to fetch their arguments in a different way from
ordinary Procs.
If stdin is in use, it'll now be put into non-canonical mode. This is almost
the same as libkrocif's behaviour, except I've set VTIME to 0, since I don't
think there's a good reason to have a terminal read complete if no characters
are available.
This also sets CCSP's branding to "Tock", so error messages now start "Tock: ".
This is for two reasons: first, the C++CSP backend still needs them, and
second, the way I'd done the removal wasn't correct; since you can have arrays
of them, abbreviate them, etc., they need to be stripped out by an earlier
pass so that other passes don't try to operate upon them.
Now that I have begun moving all the _sizes stuff forward into proper compiler passes, much of the code for handling arrays in the backends is going to become redundant:
- The tockArrayView class should eventually disappear; now that _sizes are pulled forward, there's no advantage of having this extra class (compared to just doing C and C++ arrays in the same, C-based, style)
- The declaration and use of the _sizes array everywhere should go, now that it is inserted in an earlier pass
I haven't removed as much as I should from the C backend; I am wary to touch it when Adam is about to move it over to the new CIF anyway
Most of this is mechanical: changing function names, and carrying the "wptr"
argument around. I've made the code for computing Expressions from Structureds
a bit more generic too.
The only complex bit is the handling of PAR processes, which I'm not very happy
with at the moment; they used to use the normal C calling convention, but now
you need to pack the arguments into the workspace. I'm handling this at the
moment by generating wrapper functions that do the unpacking, but it would be
better in the future to make the wrapper PROCs that we already generate have
the right interface.
This won't work for programs that use any of the top-level channels yet, since
there are no handlers for them.
Or, rather, add a new CIF-specific header, so tock_support.h is now the common
code and each of the backends has its own. This means some of the conditional
stuff can go away.
This changes the TLP code to use CCSP's stand-alone mode, and gets rid of the
old KRoC wrapper stuff. It also changes occam_stop everywhere in order to pass
the number of arguments (since ExternalCallN needs that now), and cleans up the
interaction with the C++ backend a bit.
This patch is actually an amalgam of multiple (already large) patches. Those patches conflicted (parameterised Structured vs. changes to usage checking and FlowGraph) and encountered a nasty bug in darcs 1 involving exponential time (see http://wiki.darcs.net/DarcsWiki/ConflictsFAQ for more details). Reasoning that half an hour (of 100% CPU use) was too long to apply patches, I opted to re-record the parameterised Structured changes as this new large patch. Here are the commit messages originally used for the patches (which, as mentioned, were already large patches):
A gigantic patch switching all the non-test modules over to using parameterised A.Structured
Changed the FlowGraph module again to handle any sort of Structured you want to pass to it (mainly for testing)
A further gigantic patch changing all the tests to work with the new parameterised Structured
Fixed a nasty bug involving functions being named incorrectly inside transformInputCase
Added a hand-written instance of Data for Structured that allows us to use ext1M properly
Fixed a few warnings in the code
Now that the C++ generator no longer overrides genVariable', it seems wise to remove it from the GenOps function dictionary.
You can call it via either genVariable or genVariableUnchecked anyway, so genVariable' is just used by the two former functions as implementation. It can easily be put back into the dictionary later on, if that turns out to be necessary.
This was not as straightforward as the C++ backend. CIF has no capability for supporting waiting *for* a specified time as an ALT guard; only waiting until (AFTER, in occam) a specified time. This is further complicated by the fact that when you disable an ALT timer guard in CIF, you have to be able to supply the timeout value that you waited on in the enable sequence.
Therefore, I added a pass that transforms all WaitFor guards into WaitUntil guards, by declaring nonce time variables, getting the time, and adding on the delay that we want to wait for; these actions occur just before the ALT.
This new pass is in the new BackendPasses module, into which I also moved the identifyParProcs pass. I also wrote tests for my new pass that live in the new BackendPassesTest module.
