Lists are compared lexicographically in C++ nix as of [0], and our
updated nix test suites depend on this. This implements comparison of
list values in `Value::nix_cmp` using a very similar algorithm to what
C++ does - similarly to there, this requires passing in the VM so we can
force thunks in the list elements as we go.
[0]: 09471d2680#
Change-Id: I5d8bb07f90647a1fec83f775243e21af856afbb1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7070
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
CL/7034 looks great, except that for a length-N target string it
will perform N deep copies of each of the from and to-lists. Let's
use references instead of clones.
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: Icd341213a9f0e728f9c8453cec6d23af5e1dea91
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7095
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: j4m3s <james.landrein@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
CL/6867 added support for builtins.import, which required a cyclic
reference import->globals->builtins->import. This was implemented
using a RefCell, which makes it possible to mutate the builtins
during evaluation. The commit message for CL/6867 expressed a
desire to eliminate this possibility:
This opens up a potentially dangerous footgun in which we could
mutate the builtins at runtime leading to different compiler
invocations seeing different builtins, so it'd be nice to have
some kind of "finalised" status for them or some such, but I'm not
sure how to represent that atm.
This CL replaces the RefCell with Rc::new_cyclic(), making the
globals/builtins immutable once again. At VM runtime (once opcodes
start executing) everything is the same as before this CL, except
that the Rc<RefCell<>> introduced by CL/6867 is turned into an
rc::Weak<>.
The function passed to Rc::new_cyclic works very similarly to
overlays in nixpkgs: a function takes its own result as an argument.
However instead of laziness "breaking the cycle", Rust's
Rc::new_cyclic() instead uses an rc::Weak. This is done to prevent
memory leaks rather than divergence.
This CL also resolves the following TODO from CL/6867:
// TODO: encapsulate this import weirdness in builtins
The main disadvantage of this CL is the fact that the VM now must
ensure that it holds a strong reference to the globals while a
program is executing; failure to do so will cause a panic when the
weak reference in the builtins is upgrade()d.
In theory it should be possible to create strong reference cycles
the same way Rc::new_cyclic() creates weak cycles, but these cycles
would cause a permanent memory leak -- without either an rc::Weak or
RefCell there is no way to break the cycle. At some point we will
have to implement some form of cycle collection; whatever library we
choose for that purpose is likely to provide an "immutable strong
reference cycle" primitive similar to Rc::new_cyclic(), and we
should be able to simply drop it in.
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: I34bb5821628eb97e426bdb880b02e2097402adb7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7097
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Rather than implementing all of the interesting semantics of value
comparison with a macro bound to the VM, implement the bulk of the logic
with a method on Value itself that returns an Ordering, and then use the
macro to implement the comparison against that Ordering. This has no
functional change, but paves the way to implementing lexicographic
comparison of list values, which is supported in the latest version of
upstream nix.
Change-Id: I8af1a020b41577021af5939f5edc160c407d4a9e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7069
Autosubmit: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
I played around a little bit with doing this in-place, but ended up
going with this perhaps slightly clone-heavy approach for now because
ideally most clones on Value are cheap - but later we should benchmark
alternate approaches that get to reuse allocations better if necessary
or possible.
Change-Id: If998eb2056cedefdf2fb480b0568ac8329ccfc44
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7068
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
The last bump in langVersion (5->6) in C++ Nix was due to making lists
comparable (commit `09471d2680292af48b2788108de56a8da755d661`), which
we support in Tvix with cl/7070.
Change-Id: Id3beed5150b8fb6e0a46a4d1b7e3942022a65346
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7074
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
This commit implements builtins.currentSystem, by capturing the
cargo environment variable `TARGET` and exposing it to rustc as
`TVIX_CURRENT_SYSTEM` so it can be inserted into the source code
using `env!()`.
The resulting value needs to be massaged a bit, since it is an "LLVM
triple". The current code should work for all the platforms for
which cppnix works (thanks qyliss for generating the list!). It
does *not* reject all of the triples that cppnix's configure.ac
rejects -- it is much more forgiving. We can tighten this up in a
future commit.
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: I947f504b2af5a7fee8cf0cb301421d2fc9174ce1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6986
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Since we push arguments onto a stack when calling multi-argument
functions, we actually were ending up calling `call_with` with the
arguments in the *reverse order* - we patched around this by passing the
arguments in the reverse order for `foldl'`, but it makes more sense to
have them just be the order that the function would be called with in
user surface code instead.
Change-Id: Ifddb98f46970ac89872383709c3ce758dc965c65
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7067
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
These are builtins which can be basically implemented as the identity
function from the perspective of pure evaluation, and which help us
get closer to evaluating nixpkgs.
For now, builtins added here will be "usable" and just emit a warning
about not being implemented yet.
Change-Id: I0fce94677f01c98c0392aeefb7ab353c7dc7ec82
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7060
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
This is done via a new `deepForce` function on Value. Since values can
be cyclical (for example, see the test-case), we need to do some extra
work to avoid RefCell borrow errors if we ever hit a graph cycle:
While deep-forcing values, we keep a set of thunks that we have
already seen and avoid doing any work on the same thunk twice. The set
is encapsulated in a separate type to stop potentially invalid
pointers from leaking out.
Finally, since deep_force is conceptually similar to
`VM::force_for_output` (but more suited to usage in eval since it
doesn't clone the values) this removes the latter, replacing it with
the former.
Co-Authored-By: Vincent Ambo <tazjin@tvl.su>
Change-Id: Iefddefcf09fae3b6a4d161a5873febcff54b9157
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7000
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: tazjin <tazjin@tvl.su>
This commit deduplicates the Thunk-like functionality from Closure
and unifies it with Thunk.
Specifically, we now have one and only one way of breaking reference
cycles in the Value-graph: Thunk. No other variant contains a
RefCell. This should make it easier to reason about the behavior of
the VM. InnerClosure and UpvaluesCarrier are no longer necessary.
This refactoring allowed an improvement in code generation:
`Rc<RefCell<>>`s are now created only for closures which do not have
self-references or deferred upvalues, instead of for all closures.
OpClosure has been split into two separate opcodes:
- OpClosure creates non-recursive closures with no deferred
upvalues. The VM will not create an `Rc<RefCell<>>` when executing
this instruction.
- OpThunkClosure is used for closures with self-references or
deferred upvalues. The VM will create a Thunk when executing this
opcode, but the Thunk will start out already in the
`ThunkRepr::Evaluated` state, rather than in the
`ThunkRepr::Suspeneded` state.
To avoid confusion, OpThunk has been renamed OpThunkSuspended.
Thanks to @sterni for suggesting that all this could be done without
adding an additional variant to ThunkRepr. This does however mean
that there will be mutating accesses to `ThunkRepr::Evaluated`,
which was not previously the case. The field `is_finalised:bool`
has been added to `Closure` to ensure that these mutating accesses
are performed only on finalised Closures. Both the check and the
field are present only if `#[cfg(debug_assertions)]`.
Change-Id: I04131501029772f30e28da8281d864427685097f
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7019
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Now that we're tracking formals on Lambda this ends up being quite easy;
we just pull them off of the Lambda for the argument closure and use
them to construct the result attribute set.
Change-Id: I811cb61ec34c6bef123a4043000b18c0e4ea0125
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7003
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Since we already have infra for forcing arguments to builtins, this ends
up being almost *too* simple - we just return the second argument!
Change-Id: I070d3d0b551c4dcdac095f67b31e22e0de90cbd7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6999
Reviewed-by: kanepyork <rikingcoding@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Implement an *initial* version of builtins.match, using the rust `regex`
crate for regular expressions. The rust regex crate definitely has
different semantics than nix's regular expressions - but we'd like to
see how far we can get before the incompatibility starts to matter.
This consciously leaves out any sort of memo for compiled regular
expressions (which upstream nix also has) for the sake of expediency -
in the future we should implement that so we don't have to compile the
same regular expression multiple times.
Change-Id: I5b718635831ec83397940e417a9047c4342b6fa1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6989
Tested-by: BuildkiteCI
Reviewed-by: Adam Joseph <adam@westernsemico.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Using `serde_json` for parsing JSON here, plus an `impl FromJSON for
Value`. The latter is primarily to stay "dependency light" for now -
likely going with an actual serde `Deserialize` impl in the future is
going to be way better as it allows saving significantly on intermediary
allocations.
Change-Id: I152a0448ff7c87cf7ebaac927c38912b99de1c18
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6920
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Working on https://github.com/NixOS/nix/pull/7158, I discovered that C++
Nix actually is strict in the accumulator, just not in the first value.
This seems due to the fact that in the C++ evaluator, function calls
don't seem to be thunked unconditionally and foldl' just elects not to
wrap it in a thunk (don't quote me on this summary, even though it seems
to line up with the code for primop_foldlStrict and testable behavior).
It doesn't seem worth it to risk breaking the odd Nix expression just to
be strict in one more value per invocation of foldl' (i.e. the initial
accumulator value `nul`), so let's match the existing C++ Nix behavior
here.
Change-Id: If59e62271a90d97cb440f0ca72a58ec7840d1690
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7022
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This commit causes the test eval-okay-builtins.nix to pass.
It also adds tests/tvix_tests/eval-okay-dirof.nix which has better
coverage than the nix tests for this builtin.
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: I71d96b48680696fd6e4fea3a9861742b35cfaa66
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6987
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This commit implements builtins.toPath. Like OP_ADD, it currently
does not handle string contexts.
This commit allows the
tests::nix_eval_okay_src_tests_nix_tests_eval_okay_pathexists_nix
test to pass.
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: Iadd4f7605f8f297adbd0dba187b8481c21370b6e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6996
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This makes it easier to compare currently implemented ones with the full
list.
Change-Id: Ibaffd99d05afa15fc9ab644fd101afa24fc7a1b2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7008
Tested-by: BuildkiteCI
Autosubmit: j4m3s <james.landrein@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
This commit implements builtins.baseNameOf and adds a test case
eval-okay-basenameof.nix to the test suite.
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: Ib8bbafba2ac9ca0e1d3dc5e844167f94890d9fee
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6997
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
builtins.parseDrvName should not coerce its argument to a string.
This commit fixes that oversight in my previous commit, and adds an
xfail test to cover this condition.
Thanks to @sterni for noticing this.
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: I76bc78f1a82e1e08fe5c787c563a221d55de2639
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6991
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
This commit passes nix_eval_okay_src_tests_nix_tests_eval_okay_versions_nix.
See also: https://github.com/NixOS/nix/pull/7149
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: I24605c2a0cd0da434f37f6c518f20693bfa1b799
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6913
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
When investigating discrepancies between foldl' in tvix and C++ Nix,
I discovered that C++ Nix's foldl' doesn't seem to be strict at all.
Since this seemed wrong, I looked into Haskell's foldl' implementation
which doesn't force the list elements (`val` in our code), but the
accumulation value (`res` in our code). You can look at the code here:
https://hackage.haskell.org/package/base-4.17.0.0/docs/src/GHC.List.html#foldl%27
This actually makes a lot of sense: If `res` is not forced after each
application of `op`, we'll end up thunks nested as deeply as the list is
long, potentially taking up a lot of space. This can be limited by
forcing the `res` thunk before applying `op` again (and creating a new
thunk).
I've also PR-ed an equivalent change for C++ Nix at
https://github.com/NixOS/nix/pull/7158. Since this is not merged nor
backported to our Nix 2.3 fork, I've not copied the eval fail test yet,
since it wouldn't when checking our tests against C++ Nix in depot.
Change-Id: I34edf6fc3031fc1485c3e714f2280b4fba8f004b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6947
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
This is currently implemented with a simple println inline, but in the
future we could hook into this via something pluggable on the VM.
Change-Id: Idd9cc3b34aa13d6ebc64c02aade81ecdf439656a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6938
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Currently, the span on *all* thunk force errors is the span at which the
thunk is forced, which for recursive thunk forcing ends up just being
the same span over and over again. This changes the span on thunk force
errors to be the span at which point the thunk is *created*, which is a
bit more helpful (though the printing atm is a little... crowded). To
make this work, we have to thread through the span at which a thunk is
created into a field on the thunk itself.
Change-Id: I81474810a763046e2eb3a8f07acf7d8ec708824a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6932
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: Adam Joseph <adam@westernsemico.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
With asserts compiled using conditional jumps, this ends up being quite
straightforward - the only real tricky bit is that we have to know
whether an error can or can't be handled.
Change-Id: I75617da73b7a9c5cdd888c0e26ae81d2c5c0d714
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6924
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
The process of calling a function from a builtin, especially if it's got
more than 1 arrgument, is reasonably involved and easy to get wrong due
to having to interact directly with the stack - instead of having that
done entirely manually in builtins, this wraps it up in a new
`call_with` function which handles pushing arguments onto the stack and
recursively calling the (partially applied) function.
Change-Id: I14700c639a0deca53b9a060f6d70dbc7762e9007
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6910
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Implement the listToAttrs builtin, which constructs an attribute set
from a list of attribute sets with keys name and value.
This is tested using an adaptation of the nix `eval-ok-listtoattrs.nix`,
with the utilities from `lib.nix` inlined.
Change-Id: Ib5bf743466dda9722c2c1e00797df4b58448cf0f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6894
Autosubmit: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This requires actually passing the source directory into `interpret` in
the eval tests, but otherwise this is fairly straightforward - if we're
trying to import a directory, just push `default.nix` onto it and import
that instead.
Change-Id: I0b7d4234f81977e78d14dfa651bf0cf9721017e5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6893
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Factor out the construction of Value::Attrs (including the Rc) into a
new `attrs` constructor function, to abstract away the presence of the
Rc itself.
Change-Id: I42fd4c3841e1db368db999ddd651277ff995f025
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6892
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This change is quite verbose, so a little bit of explaining:
1. To correctly format parse errors, errors must be able to return
more than one annotated span (the parser returns a list of errors
for each span).
To accomplish this, the structure of how the `Diagnostic` struct
which formats an error is constructed has changed to delegate the
creation of the `SpanLabel` vector to the kind of error.
2. The rnix structures don't have human-readable output formats by
default, so some verbose methods for formatting them in
human-readable ways have been added in the errors module. We might
want to move these out into a submodule.
3. In many cases, the errors returned by rnix are a bit strange - so
while we format them with all information that is easily available
they may look weird or not necessarily help users. Consider this CL
only a first step in the right direction.
Change-Id: Ie7dd74751af9e7ecb35d751f8b087aae5ae6e2e8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6871
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This enables the use of string paths (and, in the future,
derivations), as long as their string values represent an absolute
path.
Change-Id: I4b198efeb70415ed52f58bd1da6fa79a24dad14c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6866
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
This lets the VM emit warnings when it encounters situations that
should only be warned about at runtime.
For starters, this is used to pass through compilation warnings that
come up when `import` is used.
Change-Id: I0c4bc8c534d699999887c430d93629fadfa662c4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6868
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Adding `import` to builtins causes causes a bootstrap cycle because
the `import` builtin needs to be initialised with the set of globals
before being inserted into the globals, which also must contain
itself.
To break out of the cycle this hack wraps the builtins passed to the
compiler in an `Rc` (probably sensible anyways, as they will end up
getting cloned a bunch), containing a RefCell which gives us mutable
access to the builtins.
This opens up a potentially dangerous footgun in which we could mutate
the builtins at runtime leading to different compiler invocations
seeing different builtins, so it'd be nice to have some kind of
"finalised" status for them or some such, but I'm not sure how to
represent that atm.
Change-Id: I25f8d4d2a7e8472d401c8ba2f4bbf9d86ab2abcb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6867
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
