This actually uses coercion under the hood in C++ Nix. See the test
for an example.
Change-Id: Id56b364acf269225b6829d0b600e0222f8b3608d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8322
Reviewed-by: andi <andi@notmuch.email>
Tested-by: BuildkiteCI
This was commented out and forgotten during the generator refactor, oh
well.
Change-Id: I474b685159a955a846db462da0dd0067af177b04
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8321
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
This drops the usage of serde::Serialize, as the trait can not be used
to implement the correct semantics (function colouring!).
Instead, a manual JSON serialisation function is written which
correctly handles toString, outPath and other similar weirdnesses.
Unexpectedly, the eval-okay-tojson test from the C++ Nix test suite
now passes, too.
This fixes an issue where serialising data structures containing
derivations to JSON would fail.
Change-Id: I5c39e3d8356ee93a07eda481410f88610f6dd9f8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8209
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
These are serialised as the serialisation of the value of that field.
Change-Id: Ida51708b1f43ce09b0ec835f4e265918aa31dd09
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8205
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
These must be serialised to a JSON string of the *result* of coercing
the function application to a string.
Change-Id: Ib7f49ccd950503ddbdbf99643cd59565e26b50da
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8204
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
This shaves another 8 bytes off Value. How did that type get so big?!
Change-Id: I65e9b59a1636bd57e3cc4aec5fea16887070b832
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8153
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
The size of a `Vector<Value>` is 64 *bytes*, which is quite large, and
it bloated the entire Value type to this size.
This change adds an indirection for the inner vector through Rc.
Initially I tried to use a Box, but this breaks pointer equality
guarantees for the Vector when it is small enough to be inlined.
This reduces the size of Value from 64 to 32 bytes.
Change-Id: Ic3211e861b1966c78b2c3d536ba291fea92647fd
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8150
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
Warning: This is probably the biggest refactor in tvix-eval history,
so far.
This replaces all instances of trampolines and recursion during
evaluation of the VM loop with generators. A generator is an
asynchronous function that can be suspended to yield a message (in our
case, vm::generators::GeneratorRequest) and receive a
response (vm::generators::GeneratorResponsee).
The `genawaiter` crate provides an interpreter for generators that can
drive their execution and lets us move control flow between the VM and
suspended generators.
To do this, massive changes have occured basically everywhere in the
code. On a high-level:
1. The VM is now organised around a frame stack. A frame is either a
call frame (execution of Tvix bytecode) or a generator frame (a
running or suspended generator).
The VM has an outer loop that pops a frame off the frame stack, and
then enters an inner loop either driving the execution of the
bytecode or the execution of a generator.
Both types of frames have several branches that can result in the
frame re-enqueuing itself, and enqueuing some other work (in the
form of a different frame) on top of itself. The VM will eventually
resume the frame when everything "above" it has been suspended.
In this way, the VM's new frame stack takes over much of the work
that was previously achieved by recursion.
2. All methods previously taking a VM have been refactored into async
functions that instead emit/receive generator messages for
communication with the VM.
Notably, this includes *all* builtins.
This has had some other effects:
- Some test have been removed or commented out, either because they
tested code that was mostly already dead (nix_eq) or because they
now require generator scaffolding which we do not have in place for
tests (yet).
- Because generator functions are technically async (though no async
IO is involved), we lose the ability to use much of the Rust
standard library e.g. in builtins. This has led to many algorithms
being unrolled into iterative versions instead of iterator
combinations, and things like sorting had to be implemented from scratch.
- Many call sites that previously saw a `Result<..., ErrorKind>`
bubble up now only see the result value, as the error handling is
encapsulated within the generator loop.
This reduces number of places inside of builtin implementations
where error context can be attached to calls that can fail.
Currently what we gain in this tradeoff is significantly more
detailed span information (which we still need to bubble up, this
commit does not change the error display).
We'll need to do some analysis later of how useful the errors turn
out to be and potentially introduce some methods for attaching
context to a generator frame again.
This change is very difficult to do in stages, as it is very much an
"all or nothing" change that affects huge parts of the codebase. I've
tried to isolate changes that can be isolated into the parent CLs of
this one, but this change is still quite difficult to wrap one's mind
and I'm available to discuss it and explain things to any reviewer.
Fixes: b/238, b/237, b/251 and potentially others.
Change-Id: I39244163ff5bbecd169fe7b274df19262b515699
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8104
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Reviewed-by: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
... not just a TODO.
Most use-cases of unsafeDiscardStringContext are for cases where a
string is processed in some ways and no longer contains a "physical"
reference, but still has its context attached in C++ Nix.
We don't need to do this. This does diverge in behaviour in use-cases
related to build scheduling, but that whole behaviour will be
different in Tvix.
Change-Id: I4056d4c09f62d44d6bd52b791db03fe5556672b5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8016
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This allows parsing TOML from Tvix. We can enable the eval-okay-fromTOML
testcase from nix_tests. It uses the `toml` crate, and the serde
integration it brings with it.
Change-Id: Ic6f95aacf2aeb890116629b409752deac49dd655
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7920
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
All invocations of the builtin macro had to previously filter through
the `builtin_tuple` function, but it's more sensible to directly
return these from the macro.
Change-Id: I45600ba84d56c9528d3e92570461c319eea595ce
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7825
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
This CL addresses clippy warning len_without_is_empty
which expects `.is_empty()` method to be present when
implementing `.len()` method for an item.
Change-Id: I8878db630b9ef5853649a906b764a33299bb5dc8
Signed-off-by: Aaqa Ishtyaq <aaqaishtyaq@gmail.com>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7806
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Implements `Serialize` for `tvix_eval::Value`. Special care is taken
with serialisation of attribute sets, and forcing of thunks.
The tests should cover both cases well.
Change-Id: I9bb135bacf6f87bc6bd0bd88cef0a42308e6c335
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7803
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Autosubmit: tazjin <tazjin@tvl.su>
This placeholder should not live in the main crate anymore as we will
be injecting the real one from outside of eval, but there are still
language tests that depend on a (simple, mockable) version of it.
Change-Id: I68ea169db15cbdbeed320930d3069e21e376c90d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7783
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Code probably rarely relies on these, but it's not hard to support them.
Change-Id: I8499fec34efaf031f9c013bbd370a13db929a2a3
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7772
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
Previously the construction of globals (a compiler-only concept) and
builtins (a (now) user-facing API) was intermingled between multiple
different modules, and kind of difficult to understand.
The complexity of this had grown in large part due to the
implementation of `builtins.import`, which required the notorious
"knot-tying" trick using Rc::new_cyclic (see cl/7097) for constructing
the set of globals.
As part of the new `Evaluation` API users should have the ability to
bring their own builtins, and control explicitly whether or not impure
builtins are available (regardless of whether they're compiled in or
not).
To streamline the construction and allow the new API features to work,
this commit restructures things by making these changes:
1. The `tvix_eval::builtins` module is now only responsible for
exporting sets of builtins. It no longer has any knowledge of
whether or not certain sets (e.g. only pure, or pure+impure) are
enabled, and it has no control over which builtins are globally
available (this is now handled in the compiler).
2. The compiler module is now responsible for both constructing the
final attribute set of builtins from the set of builtins supplied
by a user, as well as for populating its globals (that is
identifiers which are available at the top-level scope).
3. The `Evaluation` API now carries a `builtins` field which is
populated with the pure builtins by default, and can be extended by
users.
4. The `import` feature has been moved into the compiler, as a
special case. In general, builtins no longer have the ability to
reference the "fix point" of the globals set.
This should not change any functionality, and in fact preserves minor
differences between Tvix/Nix that we already had (such as
`builtins.builtins` not existing).
Change-Id: Icdf5dd50eb81eb9260d89269d6e08b1e67811a2c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7738
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
The `im::OrdMap` is already small and cheap to copy while sharing
memory, so this is not required anymore.
Only the `KV` variant may have slightly larger content, but in
practice this doesn't seem to make a difference when comparing the two
variants and this one is less complicated.
Change-Id: I64a563b209a2444125653777551373cb2989ca7d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7677
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
This uses the `im::OrdMap` for `NixAttrs` to enable sharing of memory
between different iterations of a map.
This slightly speeds up eval, but not significantly. Future work might
include benchmarking whether using a `HashMap` and only ordering in
cases where order is actually required would help.
This switches to a fork of `im` that fixes some bugs with its OrdMap
implementation.
Change-Id: I2f6a5ff471b6d508c1e8a98b13f889f49c0d9537
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7676
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
The conversion from im::Vector -> Vec is cheaper for NixList
construction (of course), so where possible we should make use of
that.
This updates most builtins dealing with lists to use Vector directly,
and marks the function constructing NixList from Vec as deprecated so
that we get appropriate warnings in places where it's still in use.
These places are currently inside of JSON serialisation logic which is
in flux right now, so lets leave them as-is until it's stabilised.
Change-Id: I037f12a2800f2576db4d9526bd935efd079163f0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7671
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
This is a persistent, structurally sharing data structure which is
more efficient in some of our use-cases. I have verified the
efficiency improvement using `hyperfine` repeatedly over expressions
on nixpkgs.
Lists are not the most performance-critical structure in Nix (that
would be attribute sets), but we can already see a small (~5-10%)
improvement.
Note that there are a handful of cases where we still go via `Vec`
that need to be fixed, most notable for `builtins.sort` which can not
currently be implemented directly using `im::Vector` because of a
restrictive type bound.
Change-Id: I237cc50cbd7629a046e5a5e4601fbb40355e551d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7670
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
It's been a while since the last time, so quite a lot of stuff has
accumulated here.
Change-Id: I0762827c197b30a917ff470fd8ae8f220f6ba247
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7597
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Fixes b/212. Based on feedback in https://cl.tvl.fyi/c/depot/+/7492, all
uses of `NixAttrs::from_map` have been removed. Only `from_iter` and
`from_kv` remain.
Change-Id: I52e25f73018c2aa1843197427516b7a852503e2c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7500
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: IslandUsurper <lyle@menteeth.us>
Allows for the removal of some BTreeMap usage when constructing NixAttrs
by allowing any iterator over 2-tuples to build a NixAttrs. Some
instances of BTreeMap didn't have anything to do with making NixAttrs,
and some were just the best tool for the job, so they are left using the
old `from_map` interface.
Change-Id: I668ea600b0d93eae700a6b1861ac84502c968d78
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7492
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This passes all the function/thunk-pointer-equality tests in
cl/7369.
Change-Id: Ib47535ba2fc77a4f1c2cc2fd23d3a879e21d8b4c
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7358
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
When we start unrecursivifying (sp?) things, Rust's borrow checker
is going to be a headache; its magic only works when you use the CPU
stack as your call stack.
Fixing the borrow checker issues usually involves adding lots of
`clone()`s. Right now `NixList` is the only variant of `Value` that
isn't cheap to clone() -- all the others are either a wrapper around
Rc or else are of bounded size.
Note that this requires dropping the `DerefMut for NixList` instance
and using `Vec<Value>` instead in those situations.
Change-Id: I5a47df66855342aa2064f8f3cb7934ff422d26bd
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7359
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This implementation closely follows the original implementation in
Nix, including the use of an equality-based "set" structure to track
keys that have already been processed.
Note that this test does not yet enable the `notyetpassing` test for
builtins.genericClosure because (for as of yet unknown reasons) this
test compares against XML output (however, evaluating the test case
actually does work).
This takes us one step closer to nixpkgs eval.
This commit was written somewhere in the North Sea.
Co-Authored-By: Griffin Smith <root@gws.fyi>
Change-Id: I450a866e6f2888b27c2fe7c7f77ce0f79bfe3e6c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7310
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Add a new `documentation: Option<&'static str>` field to Builtin, and
populate it in the `#[builtins]` macro with the docstring of the builtin
function, if any.
Change-Id: Ic68fdf9b314d15a780731974234e2ae43f6a44b0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7205
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Refactor the arguments of a Builtin to be a vec of a new BuiltinArgument
struct, which contains the old strictness boolean and also a static
`name` str - this is automatically determined via the ident for the
corresponding function argument in the proc-macro case, and passed in in
the cases where we're still manually calling Builtin::new.
Currently this name is unused, but in the future this can be used as
part of a documentation system for builtins.
Change-Id: Ib9dadb15b69bf8c9ea1983a4f4f197294a2394a6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7204
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Break out all pure builtin functions to top-level functions defined
within the `pure_builtins` module in `builtins/mod.rs`.
Change-Id: I9a10660446d557b1a86da4c45a463e9a1a9b4f2d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7201
Reviewed-by: tazjin <tazjin@tvl.su>
Reviewed-by: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
Mostly as a proof-of-concept of the new proc-macros for defining
builtins, define a single builtin (the first in the list, `abort`) at
the top-level of a child module within builtins/mod.rs, and add it to
the list of builtins returned from `pure_builtins`.
If this works nicely, we can start breaking out the rest of the builtins
into the top-level too, in addition to introducing additional sets of
builtins (to differentiate between pure and impure builtins).
Change-Id: I5bdd57c57fecf8d63c9fed4fc6b1460f533b20f2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7199
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This implements builtins.split, and passes eval-okay-regex-split.nix
(which is moved out of notyetpassing).
Signed-off-by: Adam Joseph <adam@westernsemico.com>
Change-Id: Ieb0975da2058966c697ee0e2f5b3f26ccabfae57
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7143
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
This is a bit tricky because the comparator can throw errors, so we
need to propagate them out if they exist and try to avoid sorting
forever by returning a reasonable ordering in this case (as
short-circuiting is not available).
Co-Authored-By: Vincent Ambo <tazjin@tvl.su>
Change-Id: Icae1d30f43ec1ae64b2ba51e73ee467605686792
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7072
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
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
