| Age | Commit message (Collapse) | Author |
|---|
|
Breaks parsing ambiguities by removing = as an identifier in the old parser
and requiring parentheses for some expressions in the new parser
|
|
Also fix bug in mono analysis with generated variables
Breaks lots of typechecking tests because it generates unnecessary
equality tests on units (and the tests don't have generic equality),
which I'll fix next.
|
|
|
|
steps
Parser now has syntax for mutual recusion blocks
mutual {
... fundefs ...
}
which is used for parsing and pretty printing
DEF_internal_mutrec. It's stripped away by the initial_check, so the
typechecker never sees DEF_internal_mutrec. Maybe this could change,
as forcing mutual recursion to be explicit would probably be a good
thing.
Added record syntax to the new parser
New option -dmagic_hash is similar to GHC's -XMagicHash in that it
allows for identifiers to contain the special hash character, which is
used to introduce new autogenerated variables in a way that doesn't
clash with existing names.
Option -sil compiles sail down to the intermediate language defined in
sil.ott (not complete yet).
|
|
Alastair's test cases revealed that using regular ints causes issues
throughout sail, where all kinds of things can internally overflow in
edge cases. This either causes crashes (e.g. int_of_string fails for
big ints) or bizarre inexplicable behaviour. This patch switches the
sail AST to use big_int rather than int, and updates everything
accordingly.
This touches everything and there may be bugs where I mistranslated
things, and also n = m will still typecheck with big_ints but fail at
runtime (ocaml seems to have decided that static typing is unnecessary
for equality...), as it needs to be changed to eq_big_int.
I also got rid of the old unused ocaml backend while I was updating
things, so as to not have to fix it.
|
|
There are several key changes here:
1) This commit allows for user defined operations in n-expressions
using the Nexp_app constructor. These operations are linked to
operators in the SMT solver, by using the smt extern when defining
operations. Notably, this allows integer division and modular
arithmetic to be used in types. This is best demonstrated with an
example:
infixl 7 /
infixl 7 %
val operator / = {
smt: "div",
ocaml: "quotient"
} : forall 'n 'm, 'm != 0. (atom('n), atom('m)) -> {'o, 'o = 'n / 'm. atom('o)}
val mod_atom = {
smt: "mod",
ocaml: "modulus"
} : forall 'n 'm. (atom('n), atom('m)) -> {'o, 'o = mod_atom('n, 'm). atom('o)}
val "print_int" : (string, int) -> unit
overload operator % = mod_atom
val main : unit -> unit
function main () = {
let 'm : {'x, 'x % 3 = 1. atom('x)} = 4;
let 'n = m / 3;
_prove(constraint(('m - 1) % 3 = 0));
_prove(constraint('n * 3 + 1 = 'm));
(* let x = 3 / 0; (* Will fail *) *)
print_int("n = ", n);
()
}
As can be seen, these nexp ops can be arbitrary user defined operators
and even operator overloading works (although there are some caveats).
This feature is very experimental, and some things won't work very
well once you use custom operators - notably unification. However,
this not necissarily a downside, because if restrict yourself to the
subset of sail types that correspond to liquid types, then there is
never a need to unify n-expressions. Looking further ahead, if we
switch to a liquid type system a la minisail, then we no longer need
to treat + - and * specially in n-expressions. So possible future
refactorings could involve collapsing the Nexp datatype.
2) The typechecker is stricter about valspecs (and other types) being
well-formed. This is a breaking change because previously we allowed
things like:
val f : atom('n) -> atom('n)
and now this must be
val f : forall 'n. atom('n) -> atom('n)
if we want to allow the first syntax, then initial-check should
desugar it this way - but it must be well-formed by the time it hits
the type-checker, otherwise it's not clear that we do the right
thing. Note we can actually have top-level type variables by using
top-level let bindings with P_var. There's a future line of
refactoring that would make it so that type variables can shadow each
other properly (we should do this) - currently they all have to have
unique names.
3) atom('n) is no longer syntactic sugar for range('n, 'n). The reason
why we want to do this is that if we wanted to be smart about what
sail operations can be translated into SMT operations at the type
level we care very much that they talk about atoms and not
ranges. Why? Because atom is the term level representation of a
specific type variable so it's clear how to map between term level
functions and type level functions, i.e. (atom('n) -> atom('n)) can be
reflected at the type level by a type level function with kind Int ->
Int, but the same is not true for range. Furthermore, both are
interdefinable as
atom('n) -> range('n, 'n)
range('n, 'm) -> {'o, 'n <= 'o <= 'm. atom('n)}
and I think the second is actually slightly more elegant. This change
*should* be backwards compatible, as the type-checker knows how to
convert from atom to ranges and unify them with each other, but there
may be bugs introduced here...
|
|
For example,
val test = { ocaml: "test_ocaml" } : unit -> unit
will only be external for OCaml. For other backends, it will have to be
defined.
|
|
For example:
val test = { ocaml: "test_ocaml", lem: "test_lem" } : unit -> unit
val main : unit -> unit
function main () = {
test ();
}
for a backend not explicitly provided, the extern name would be simply
"test" in this case, i.e. the string version of the id.
Also fixed some bugs in the ocaml backend.
|
|
What does this mean? Basically undefined values can't be created for
types that contain free type variables, so for example: undefined :
list(int) is good, but undefined : list('a) is bad. The reason we want
to do this is because we can't compile them away statically, and this
leads to situations where type-checkable code fails in the rewriter
and gives horribly confusing error messages that don't relate to code
the user wrote at all.
As an example the following used to typecheck, but fail in the
rewriter with a confusing error message, whereas now the typechecker
should reject all cases which would trigger that failure in rewriting.
val test : forall ('a:Type). list('a) -> unit effect {wreg, undef}
function test xs = {
xs_mut = xs;
xs_mut = undefined; (* We don't know what kind of undefined 'a is *)
()
}
There's a slight hitch, namely that in the undefined_type functions
created by the -undefined_gen option, we do want to allow functions
that have polymorphic undefined values, so that we can generate
undefined generators for polymorphic datatypes such as:
union option ('a:Type) = {
Some : 'a,
None
}
These functions are always have a specific form that allows the
rewriter to succesfully remove the polymorphic undefined value for the
'a argument for Sone. As such there's a flag in the typechecking
environment for polymorphic undefineds that is enabled when it sees a
function with the undefined_ name prefix.
Also: Fixed some test cases that were broken due to escape effect being added to assert.
|
|
Translates atom('n) types into itself('n) types that won't be erased
Also exports more rewriting functions
|
|
|
|
|
|
Fixed an issue in ast.ml with uneccessary type variables
|
|
|
|
Menhir pretty printer can now print enough sail to be useful with ASL parser
Fixity declarations are now preserved in the AST
Menhir parser now runs without the Pre-lexer
Ocaml backend now supports variant typedefs, as the machinery to
generate arbitrary instances of variant types has been added to the
-undefined_gen flag
|
|
|
|
New option -memo_z3 memoizes calls to the Z3 solver, and saves these
results between calls to sail. This greatly increases the performance
of sail when re-checking large specifications by about an order of
magnitude. For example:
time sail -no_effects prelude.sail aarch64_no_vector.sail
real 0m4.391s
user 0m0.856s
sys 0m0.464s
After running with -memo_z3 once, running again gives:
time sail -memo_z3 -no_effects prelude.sail aarch64_no_vector.sail
real 0m0.457s
user 0m0.448s
sys 0m0.008s
Both the old and the new parser should now have better error messages
where the location of the parse error is displayed visually in the
error message and highlighted.
|
|
|
|
|
|
|
|
|
|
|
|
also rename NC_nat_set_bounded to NC_set (it was an int set not a nat set anyway)
|
|
just LB_val in AST
also rename functions in rewriter.ml appropriately.
|
|
|
|
- Modified how sail type error messages are displayed. The
typechecker, rather than immediately outputing a string has a
datatype for error types, which are the pretty-printed using a
PPrint pretty-printer. Needs more work for all the error messages.
- Error messages now attempt to highlight the part of the file where
the error occurred, by printing the line the error is on and
highlighting where the error message is in red. Again, this needs to
be made more robust, especially when the error messages span
multiple lines.
Other things
- Improved new parser and lexer. Made the lexer & parser handling of
colons simpler and more intuitive.
- Added some more typechecking test cases
|
|
experiments
|
|
|
|
Works for basic examples with arbitrary register types, so for example we can compile:
val extern string -> unit effect pure print = "print_endline"
val unit -> string effect pure hello_world
function hello_world () = {
return "Hello, World!";
"Unreachable"
}
val unit -> unit effect {wreg, rreg} main
register string REG
function main () = {
REG := "Hello, Sail!";
print(REG);
REG := hello_world ();
print(REG);
return ()
}
into
open Sail_lib;;
let zhello_world () = with_return (fun r ->
begin r.return "Hello, World!"; "Unreachable" end);;
let zREG : (string) ref = ref (undefined_string ());;
let zmain () = with_return (fun r ->
begin
zREG := "Hello, Sail!";
print_endline !zREG;
zREG := zhello_world ();
print_endline !zREG;
r.return ()
end);;
let initialize_registers () = with_return (fun r -> zREG := undefined_string ());;
with the arbitrary register types and early returns being handled
appropriately, given a suitable implementation for Sail_lib
|
|
Also generate a function which initializes all the registers in a spec to undefined. This gives us the information we need post-rewriting to generate registers of any arbitrary type.
|
|
backed.
Ocaml doesn't support undefined values, so we need a way to remove
them from the specification in order to generate good ocaml
code. There are more subtle issues to - like if we initialize a
mutable variable with an undefined list, then the ocaml runtime has no
way of telling what it's length should be (as this information is
removed by the simple_types pass).
We therefore rewrite undefined literals with calls to functions that
create undefined types, e.g.
(bool) undefined becomes undefined_bool ()
(vector<'n,'m,dec,bit>) undefined becomes undefined_vector(sizeof 'n, sizeof 'm, undefined_bit ())
We therefore have to generate undefined_X functions for any user
defined datatype X. initial_check seems to be the logical place for
this. This is straightforward provided the user defined types are
not-recursive (and it shouldn't be too bad even if they are).
|
|
The reason you want this is to do something like (note new parser only):
*********
default Order dec
type bits 'n:Int = vector('n - 1, 'n, dec, bit)
val zeros : forall 'n. atom('n) -> bits('n)
val decode : bool -> unit
function decode b = {
let 'datasize: {|32, 64|} = if b then 32 else 64;
let imm: bits('datasize) = zeros(datasize);
()
}
*********
for the ASL decode functions, where the typechecker now knows that the
datasize variable and the length of imm are the same.
|
|
|
|
to translate exceptions in ASL. See test/typecheck/pass/trycatch.sail.
|
|
operators.
|
|
|
|
|
|
|
|
|
|
|
|
Fixed some bugs in the initial check that caused valid code to fail to
parse
Add a nid utility function that creates an id n-expression, similar to
nvar, nconstant etc
|
|
See test/typecheck/pass/cons_pattern.sail for an example.
Also cleaned up the propagating effects code by making some of the
variable names less verbose
|
|
Modified initial_check.ml so it no longer requires type_internal. It's
still needs cleaned up in a few ways. Most of the things it's trying
to do could be done nicer if we took some time to re-factor it, and
some of the things should just be handled by the main typechecker,
leaving it as a think layer between the parse_ast and the ast.
Now that's done everything can be switched to the new typechecker and
the _new suffixes were deleted from everything except the
monomorphisation pass because I don't know the status of that.
|
|
1) Added a new construct to the expression level: constraint. This is the
essentially the boolean form of sizeof. Whereas sizeof takes a nexp
and has type [:'n:], constraint takes a n_constraint and returns a
boolean. The hope is this will allow for flow typing to be represented
more explicitly in the generatated sail from ASL.
For example we could have something like:
default Order dec
val bit[64] -> unit effect pure test64
val forall 'n, ('n = 32 | 'n = 64 | 'n = 10) & 'n != 43. bit['n] -> unit effect pure test
function forall 'n. unit test addr =
{
if constraint('n = 32) then {
()
} else {
assert(constraint('n = 64), "64-bit mode");
test64(addr)
}
}
2) The other thing this example demonstrates is that flow constraints
now work with assert and not just if. Even though flow typing will
only guarantee us that 'n != 32 in the else branch, the assert gives
us 'n = 64. This is very useful as it's a common idiom in the ARM
spec to guarantee such things with an assert.
3) Added != to the n_constraint language
4) Changed the n_constraint language to add or and and as constructs
in constraints. Previously one could have a list of conjuncts each of
which were simple inequalites or set constraints, now one can do for
example:
val forall 'n, ('n = 32 | 'n = 64) & 'n in {32, 64}. bit['n] -> unit effect pure test
This has the very nice upside that every n_constraint can now be
negatated when flow-typing if statements. Note also that 'in' has been
introduced as a synonym for 'IN' in the constraint 'n in {32,64}. The
use of a block capital keyword was a bit odd there because all the
other keywords are lowercase.
|
|
|
|
Introduces a when keyword for case statements, as the Pat_when constructor for pexp's in the AST. This allows us to write things like:
typedef T = const union { int C1; int C2 }
function int test ((int) x, (T) y) =
switch y {
case (C1(z)) when z == 0 -> 0
case (C1(z)) when z != 0 -> x quot z
case (C2(z)) -> z
}
this should make translation from ASL's patterns much more straightforward
|
|
* Experimented with using list<bit> to clean up manually monomorphised code in MIPS tlb
* Added option -dtc_verbose to control verbosity of new typechecker
* Allowed functions with val specs to omit their type declarations
|
|
New typechecker has no builtin overloaded operators - instead can now
write something in SAIL like:
overload (deinfix +) [id1; id2; id3]
to set up functions id1, id2, and id3 as overloadings for the +
operator. Any identifier can be overloaded, not just infix ones. This
is done in a backwards compatible way, so the old typechecker removes
the DEF_overload nodes from the ast so the various backends never see
it.
|
|
Added a new feature for implicit casts - now allowable implicit casts
can be specified by the user via a valspec such as
val cast forall Type 'a, Type 'b. 'a -> 'b effect pure cast_anything
with a new AST constructor to represent this as VS_cast_spec. This
constructor is removed and replaced with the standard val spec by the
old typechecker for backwards compatability, so it's only used by the
new typechecker, and won't appear in the ast once it reaches the
backends.
Also added Num as a synonym for the Nat kind in the parser, via the
confusingly named NatNum token (Num by itself was already taken for a
numeric constant).
|
|
# Conflicts:
# src/lem_interp/interp.lem
# src/lem_interp/interp_inter_imp.lem
# src/lem_interp/interp_interface.lem
# src/parser.mly
# src/pretty_print_lem.ml
|
