Instead of using a suspended native thunk, calculate and optionally
insert the storeDir builtin when the VM is constructed.
We already have the IO handle available at this point and can just
check whether a storeDir is present, and insert its absolute value as
a builtin.
Change-Id: If966eee6ff26dc888b6e888e7c46170c0c346b05
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8145
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
This is a ThunkSet wrapped to be shareable, which will be required
once ThunkSets are embedded in futures.
Change-Id: I5a067b7972ac86e4d354c75ef05c86b2284c1137
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8144
Tested-by: BuildkiteCI
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Again simplifying some code down the line, where bits of code that
construct attribute sets already have the final structure available.
Change-Id: I0bb7a1daa63298122b51be73d35d695a4f73f8b0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8140
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
This simplifies some code down the line.
Change-Id: I58dd71e796e11479f44516cf24932f8061843d23
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8139
Tested-by: BuildkiteCI
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Some of these strings are actually just the nix hash representation of
the hash calculated earlier.
There's another one passed around via calculate_drv_replacement_str, but
that's left for a followup.
Change-Id: Id99a2a926a980d679eb49c34ee6a36bf224699b0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8218
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: flokli <flokli@flokli.de>
This provides a way to construct a NixHash struct without parsing
strings.
Change-Id: I947d96e15e51e72d5b02929cda8c5fc31d81253a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8217
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: tazjin <tazjin@tvl.su>
We ironically didn't add support parsing for the "native" format that
Nix uses under the hood.
This extends the from_str method to peek at the prefix of the string to
determine whether to try decoding as SRI, Nix string, or whether it
should be a bare digest.
Change-Id: I33efd24968b16f86eff18305b4ca8f112c7131d7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8216
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
This will be used for both Nix hash strings and hash strings without the
algo specified.
Change-Id: Iedfe5494fba5f2be00614ba0fc38bf659eafd447
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8215
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This adds addresses of thunk and closure chunks to the debug output
displayed when dumping bytecode.
This makes it possible to see in the dump which thunks are referenced
by constants in other thunks.
Change-Id: I2c98de5227e7cb415666cd3134c947a56979dc80
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8137
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
This CL removes calling into_iter on a reference, as it will
not move out it's content into resulting iterator.
Change-Id: Ifcc10b7cf33b98453570cbcec3eb82ffaba2ffcb
Signed-off-by: Aaqa Ishtyaq <aaqaishtyaq@gmail.com>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8126
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This CL removes redundant clone from value which is
going to be dropped without further use.
Change-Id: Ibd2a724853c5cfbf8ca40bf0b3adf0fab89b9be5
Signed-off-by: Aaqa Ishtyaq <aaqaishtyaq@gmail.com>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8125
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Instead of using an explicit closure to clone elements, use .cloned().
Change-Id: I31f0f0bad2b4935e1a8d91fa0d14163c94182e1b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8109
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
The size field already is u32, we don't need to convert here.
Change-Id: Ie29819aa2d1d8022e9bd73fcf05b140e45c967a9
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8107
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
We want the address that the Rc is pointing to, not the address of the
Rc.
Change-Id: I8eba21677f242bbe4166c74d4aa4269c316076e3
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8045
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This CL address clippy warning which expects to
use `writeln` instead of `write` for strings with
new line.
Change-Id: Ia72a07502c60cfd489ecf1e3833b9d42d44a8b17
Signed-off-by: Aaqa Ishtyaq <aaqaishtyaq@gmail.com>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8030
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This CL address clippy warning about finding the zero
length of something using `is_empty()` instead of `len() == 0`.
Change-Id: I2b36c7c7b65b733609fc0dcd33be06f9d772bc9b
Signed-off-by: Aaqa Ishtyaq <aaqaishtyaq@gmail.com>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8029
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This branch was missing, and an assumption elsewhere just executed the
returned (broken) bytecode.
This fixes b/253.
Change-Id: I015023ba921bc08ea03882167f1f560feca25e50
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8090
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: tazjin <tazjin@tvl.su>
These should be inspectable by callers.
Change-Id: Ia9ef871aa63958d06066aaea61b2aecbd217369b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8089
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
Nix accepts SRI hashes that are missing their padding characters
in base64, as seen in
7e49471316/pkgs/development/libraries/kerberos/krb5.nix .
It only seems to work in the SRI case, not with `sha256` being set to a
(nopad) base64 string.
Add regression tests for this, and document why we don't want to support
*additional* characters afterwards.
Reported in https://b.tvl.fyi/issues/252
Change-Id: I9ffc2b417501b426ced1894a9cbf95ff5f0e5159
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8037
Reviewed-by: Alyssa Ross <hi@alyssa.is>
Tested-by: BuildkiteCI
Further emphasize Read() can be used to ask for blobs OR chunks, and
that clients usually want to stat and then request (smaller) chunks,
rather than reading whole blobs.
Also clarify that the chunking used to send BlobChunks over has nothing
to do with the chunk sizes communicated in a Stat() request.
Change-Id: Ia615d190aae570611de2655b11342a14d0b75976
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8028
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Plain paths like `foo/bar.nix` are also allowed, so we can not
determine this based on the prefix.
The upstream PR that is referenced in a comment here has a
significantly different interface than we expected, so I'm not
touching that comment yet in this CL before I've had more time to
digest it.
Change-Id: Iea33bbb35de9c00a7d7fedf64d02253c75c1cc9e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8032
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: Alyssa Ross <hi@alyssa.is>
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Our fork fixes a small bug (https://github.com/jneem/wu-manber/pull/1)
but it's not clear whether upstream will accept patches, so for now
lets point this directly at our fork.
Change-Id: Iccdcedae3e9a8b783241431787c952561d032694
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8031
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
We only use Rc in `impl EvalIO for StdIO`, which is only included when
building with the "impure" feature.
Change-Id: Id29d647c899cbfcdda11abfb9fabd5aa7e24299f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8025
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This reduces the size of `Builtin` from 88 (!) bytes to 8, and as the
largest variant of `Value`, the size of that type from 96 to 64.
The next largest type is NixList, clocking in at 64 bytes.
This has noticeable performance impact. In an implementation without
disk I/O, evaluating nixpkgs.stdenv looks like this:
Benchmark 1: tvix -E '(import <nixpkgs> {}).stdenv.drvPath'
Time (mean ± σ): 1.151 s ± 0.003 s [User: 1.041 s, System: 0.109 s]
Range (min … max): 1.147 s … 1.155 s 10 runs
After this change, it looks like this:
Benchmark 1: tvix -E '(import <nixpkgs> {}).stdenv.drvPath'
Time (mean ± σ): 1.046 s ± 0.004 s [User: 0.954 s, System: 0.092 s]
Range (min … max): 1.041 s … 1.053 s 10 runs
Change-Id: I5ab7cc02a9a450c0227daf1f1f72966358311ebb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8027
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
When resolving a select expression (`attrs.name` or `attrs.name or
default`), if the set compiles to a constant attribute set (as is most
notably the case with `builtins`) we can backtrack and replace that
attribute set directly with the compiled value.
For something like `builtins.length`, this will directly emit an
`OpConstant` that leaves the `length` builtin on the stack.
Change-Id: I639654e065a06e8cfcbcacb528c6da7ec9e513ee
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7957
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
This was reflowed in a funny way. Move the whole command into its own
line, to prevent it from happening.
Change-Id: Ifba4daf418487ca4c32586820071930d29020f42
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8026
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This fixes a very complicated bug (b/246). Evaluation
progresses *much* further after this, leading to several less
complicated bugs likely being uncovered by this
What was the problem?
=====================
Previously, when evaluating a thunk, we had a code path that looked
like this:
match *thunk {
ThunkRepr::Evaluated(Value::Thunk(ref inner_thunk)) => {
let inner_repr = inner_thunk.0.borrow().clone();
drop(thunk);
self.0.replace(inner_repr);
}
/* ... */
}
This code path created a copy of the inner `ThunkRepr` of a nested
thunk, and moved that copy into the `ThunkRepr` of the parent.
The effect of this was that the original `ThunkRepr` (unforced!) lived
on in the original thunk, without the memoization of the subsequent
forcing applying to it.
This had the result that Tvix would repeatedly evaluate these thunks
without ever memoizing them, if they occured repeatedly as shared
inner thunks. Most notably, this would *always* occur when
builtins.import was used.
What's the solution?
====================
I have completely rewritten `Thunk::force_trampoline_self` to make all
flows that can occur in it explicit. I have also removed the outer
loop inside of that function, and resorted to more use of trampolining
instead.
The function is now well-commented and it should be possible to read
it from top-to-bottom and get a general sense of what is going on,
though the trampolining itself (which is implemented in the VM) needs
to be at least partially understood for this.
What's the new problem(s)?
==========================
One new (known) problem is that we have to construct `Error` instances
in all error types here, but we do not have spans available in some
thunk-related situations. Due to b/238 we cannot ask the VM for an
arbitrary span from the callsite leading to the force. This means that
there are now code paths where, under certain conditions, causing an
evaluation error during thunk forcing will panic.
To fix this we will need to investigate and fix b/238, and/or add a
span tracking mechanism to thunks themselves.
What other impacts does this have?
==================================
With this commit, eval of nixpkgs mostly succeeds (things like stdenv
evaluate to the same hashes for us and C++ Nix, meaning we now
construct identical derivations without eval breaking).
Due to this we progress much further into nixpkgs, which lets us
uncover more additional bugs. For example, after this commit we can
quickly see that cl/7949 introduces some kind of behavioural issue and
should not be merged as-is (this was not apparent before).
Additionally, tvix-eval is now seemingly very fast. When doing
performance analysis of a nixpkgs eval, we now mostly see the code
path for shelling out to C++ Nix to add things to the store in there.
We still need those code paths, so we can not (yet) do a performance
analysis beyond that.
Change-Id: I738525bad8bc5ede5d8c737f023b14b8f4160612
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8012
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
We need to distinguish explicitly between the paths used for the
scanner, and the paths that populate the derivation inputs. The full
paths must be accessible from the result of the refscanner to populate
drv fields correctly.
This was previously hidden by debug changes that masked actual IO
operations with no-ops.
Change-Id: I037af6e6bbe2b573034d695f8779bee1b56bc125
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8022
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Creates a cache of imported literal files (e.g.
`./default-builder.sh`) which avoids shelling out to Nix for each
instance of the same file.
Note that a better way to tackle this is to create memoizable thunks
for these expressions in the compiler, but we are lacking a little bit
of infrastructure for that at the moment.
Change-Id: Ibc062b20d81e97dd3986e734d225a744e1779fe7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8015
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
Switch out the string-scanning algorithm used in the reference scanner.
The construction of aho-corasick automata made up the vast majority of
runtime when evaluating nixpkgs previously. While the actual scanning
with a constructed automaton is relatively fast, we almost never scan
for the same set of strings twice and the cost is not worth it.
An algorithm that better matches our needs is the Wu-Manber multiple
string match algorithm, which works efficiently on *long* and *random*
strings of the *same length*, which describes store paths (up to their
hash component).
This switches the refscanner crate to a Rust implementation[0][1] of
this algorithm.
This has several implications:
1. This crate does not provide a way to scan streams. I'm not sure if
this is an inherent problem with the algorithm (probably not, but
it would need buffering). Either way, related functions and
tests (which were actually unused) have been removed.
2. All strings need to be of the same length. For this reason, we
truncate the known paths after their hash part (they are still
unique, of course).
3. Passing an empty set of matches, or a match that is shorter than
the length of a store path, causes the crate to panic. We safeguard
against this by completely skipping the refscanning if there are no
known paths (i.e. when evaluating the first derivation of an eval),
and by bailing out of scanning a string that is shorter than a
store path.
On the upside, this reduces overall runtime to less 1/5 of what it was
before when evaluating `pkgs.stdenv.drvPath`.
[0]: Frankly, it's a random, research-grade MIT-licensed
crate that I found on Github:
https://github.com/jneem/wu-manber
[1]: We probably want to rewrite or at least fork the above crate, and
add things like a three-byte wide scanner. Evaluating large
portions of nixpkgs can easily lead to more than 65k derivations
being scanned for.
Change-Id: I08926778e1e5d5a87fc9ac26e0437aed8bbd9eb0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8017
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
The README was very sparse before and we've actually had people email
us (as it says to contact us) just to ask what Tvix *is*. This should
answer some questions!
Change-Id: I0f248cb060eccfe086468afed1d648652b35dfd1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8018
Tested-by: BuildkiteCI
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: flokli <flokli@flokli.de>
... 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
... instead of a BTreeMap, as we do not need ordering guarantees here.
HashMaps are noticeably faster here (especially as we've been sorting
essentially random data!).
Change-Id: Ie92d74286df9f763c04c9b226ef1066ee8484c13
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8014
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Autosubmit: tazjin <tazjin@tvl.su>
If the tvix view is cloned through josh, you don't use mg, but a
`shell.nix` is provided.
Also, add the `git clone` command, so people browsing tvix source code
in the browser know where to clone from.
Change-Id: I18483d6a52953f9f4eafd1533ea69afb0e329b04
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8001
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
