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2023-06-14 r/6298 test(tvix/eval): re-enable blackhole teststerni1-0/+0
Change-Id: Id933f3bd708aa3342b9fd6a5584e65ee11751ff8 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8773 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su> Autosubmit: sterni <sternenseemann@systemli.org>
2023-06-14 r/6297 fix(tvix/eval): don't thunk home relative pathssterni2-11/+13
C++ Nix resolves home relative paths at [parse] time. This is not an option for us, since it prevents being able to separate the compilation and execution phase later (e.g. precompiled nix expressions). However, a practical consequence of this is that paths expressions are always literals (strict) and never thunks. [parse]: https://github.com/NixOS/nix/blob/7066d21a0ddb421967980094222c4bc1f5a0f45a/src/libexpr/parser.y#L518-L527 Change-Id: Ie4b9dc68f62c86d6c7fd5f1c9460c850d97ed1ca Reviewed-on: https://cl.tvl.fyi/c/depot/+/7041 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su>
2023-06-12 r/6268 test(tvix/eval): builtins.substring's behavior with negative argssterni3-0/+9
Change-Id: Ie8b97d174e9d58e33bf08c9b9e0afeeddd089ba8 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8700 Autosubmit: sterni <sternenseemann@systemli.org> Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI
2023-06-12 r/6267 fix(tvix/eval): allow negative substring lengthsLinus Heckemann2-21/+5
Nix uses string::substr without checking the sign of the length[1]. The NixOS testing infrastructure relies on this[2], and on the implicit conversion of that to the maximum possible value for a size_t. [1]: https://github.com/NixOS/nix/blob/ecae62020b64914d9859a71ce197d03688c6133c/src/libexpr/primops.cc#L3597 [2]: https://github.com/NixOS/nixpkgs/blob/c7c298471676ac1c7789ab3c424fbcebecaa6791/nixos/lib/testing/driver.nix#L29 Change-Id: I6d0caf6830b6bda3fdf44c40c81de6a1befeca7b Reviewed-on: https://cl.tvl.fyi/c/depot/+/8746 Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI
2023-06-11 r/6266 fix(tvix/eval): emit only warnings on shadowed outputsLinus Heckemann2-1/+8
Unfortunately, nixpkgs has at least one case[1] where the out environment variable is shadowed -- though it doesn't cause a problem, since it's shadowed with the correct value, odd as this may be! [1]: https://github.com/NixOS/nixpkgs/blob/c7c298471676ac1c7789ab3c424fbcebecaa6791/pkgs/development/python-modules/pybind11/default.nix#L19 Change-Id: Ibf6790d2484dc9cce8e424feeb5886664d498dc3 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8696 Autosubmit: tazjin <tazjin@tvl.su> Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI
2023-06-07 r/6244 fix(tvix/eval): use normal thunking behavior for default in formalssterni2-9/+7
When comparing to C++ Nix, we notice that the thunking of default expressions in function formals corresponds to their normal thunking, e.g. literals are not thunked. This means that we can just invoke compile() without much of a care and trust that it will sort it out correctly. If function formals blow up as a result of this, it likely indicates that the expression is treated incorrectly by compile(), not compile_param_pattern(). Change-Id: I64acbff2f251423eb72ce43e56a0603379305e1d Reviewed-on: https://cl.tvl.fyi/c/depot/+/8704 Autosubmit: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su>
2023-06-07 r/6243 fix(tvix/eval): type check function argument with set patternsterni5-0/+18
C++ Nix forces and typechecks the passed argument even if it is not necessary in order to compute the return value of the function. I discovered this when I thought our formals miscompilation might be that we are too strict, but doesn't look like it in this case. Change-Id: Ifb3c92592293052c489d1e3ae8c7c54e4b6b4dc6 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8701 Tested-by: BuildkiteCI Autosubmit: sterni <sternenseemann@systemli.org> Reviewed-by: tazjin <tazjin@tvl.su>
2023-06-07 r/6242 refactor(tvix/eval): don't track idx twice in compile_param_patternsterni1-9/+7
Change-Id: I27f9105ddb20d84342550b2a73b479a7764ee3fe Reviewed-on: https://cl.tvl.fyi/c/depot/+/8699 Reviewed-by: tazjin <tazjin@tvl.su> Autosubmit: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2023-05-29 r/6219 test(tvix/eval): check thunking behavior of basic exprssterni1-0/+55
nix_oracle.rs now gives us the possibility to check this by stuffing the expressions in a list. In fact, the incorrect behavior fixed in - cl/8656 - cl/8655 - cl/8662 was discovered using this test suite. Change-Id: Id0ab01ee6be0b875791214e0a72a2ac941c46c96 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8658 Autosubmit: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su>
2023-05-29 r/6218 refactor(tvix/eval/nix_oracle): allow specifying eval strictnesssterni1-10/+28
This will be useful for comparing thunking behavior to C++ Nix. I considered adding this capability to the tvix_tests/nix_tests infrastructure, but as it would require changing the test file naming scheme to do it in a clean way, I've postponed it–it's nice that our tests are compatible with C++ Nix's test suite. Change-Id: I60bcdd98ed25140e716f0858f8dc28f21ab957aa Reviewed-on: https://cl.tvl.fyi/c/depot/+/8657 Autosubmit: sterni <sternenseemann@systemli.org> Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI
2023-05-29 r/6217 fix(tvix/eval): thunk lambda expressionssterni1-5/+3
As cl/8658 and b/274 reveal, lambda expressions are also wrapped in thunks. Resolves b/274. Change-Id: I02fe5c8730ac76748d940e4f4427116587875275 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8662 Autosubmit: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su>
2023-05-29 r/6216 fix(tvix/eval): thunk HasAttr expressionssterni1-1/+3
HasAttrs was weird because with longer attribute paths it would sometimes not turn out to be a thunk. If it was a thunk, it'd usually still do some eval strictly which we'll want to avoid. Verified against C++ Nix using a new test suite introduced in a later CL. Change-Id: I6d047ccc68d046bb268462f170a3c4f3c5ddeffe Reviewed-on: https://cl.tvl.fyi/c/depot/+/8656 Autosubmit: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su>
2023-05-29 r/6215 fix(tvix/eval): thunk legacy let to match regular onesterni1-1/+3
Probably no real world code broken by this overzealous evaluation, but let's be thorough! Change-Id: Ib405a677182eab7940ace940c68e107573473a54 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8655 Reviewed-by: tazjin <tazjin@tvl.su> Autosubmit: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2023-05-29 r/6214 fix(tvix/eval): thunk unary operator applicationssterni1-1/+1
Unary operator applications are thunked which can easily be observed by nix-instantiate --eval -E '[ (!true) (-1) ]' Unfortunately, there are few simple expressions where this makes a difference in the end result. Thus it only cropped up when using nixpkgs for cross compilation: Here we would compile the expression !(stdenv.cc.isGNU or false) to assemble python3Minimal's passthru attribute set (at least this seems to be the most likely explanation from the backtraces I've studied). This means that an unthunked <stdenv.cc.isGNU or false> OpForce OpInvert would be performed in order to assemble this attribute set, causing stdenv.cc to be evaluated too early, causing an infinite recursion. Resolves b/273. It seems that having a test suite that doesn't use --strict and relies on thunks rendered as <CODE> would be beneficial for catching such issues. I've not been able to find a test case with --strict that demonstrates the problem fixed in this CL. Change-Id: I640a5827b963f5b9d0f86fa2142e75e3a6bbee78 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8654 Tested-by: BuildkiteCI Autosubmit: sterni <sternenseemann@systemli.org> Reviewed-by: tazjin <tazjin@tvl.su>
2023-05-26 r/6207 fix(tvix): don't call function eagerly in genList, map & mapAttrssterni4-5/+88
mapAttrs, map and genList call Nix functions provided by the caller and store the result of applying them in a Nix data structure that does not force all of its contents when forced itself. This means that when such a builtin application is forced, the Nix function calls performed by the builtin should not be forced: They may be forced later, but it is also possible that they will never be forced, e.g. in builtins.length (builtins.map (builtins.add 2) [ 1 2 3 ]) it is not necessary to compute a single application of builtins.add. Since request_call_with immediately performs the function call requested, Tvix would compute function applications unnecessarily before this change. Because this was not followed by a request_force, the impact of this was relatively low in Nix code (most functions return a new thunk after being applied), but it was enough to cause a lot of bogus builtins.trace applications when evaluating anything from `lib.modules`. The newly added test includes many cases where Tvix previously incorrectly applied a builtin, breaking a working expression. To fix this we add a new helper to construct a Thunk performing a function application at runtime from a function and argument given as `Value`s. This mimics the compiler's compile_apply(), but does itself not require a compiler, since the necessary Lambda can be constructed independently. I also looked into other builtins that call a Nix function to verify that they don't exhibit such a problem: - Many builtins immediately use the resulting value in a way that makes it necessary to compute all the function calls they do as soon as the outer builtin application is forced: * all * any * filter * groupBy * partition - concatMap needs to (shallowly) force the returned list for concatenation. - foldl' is strict in the application of `op` (I added a comment that makes this explicit). - genericClosure needs to (shallowly) force the resulting list and some keys of the attribute sets inside. Resolves b/272. Change-Id: I1fa53f744bcffc035da84c1f97ed25d146830446 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8651 Autosubmit: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su>
2023-05-25 r/6205 feat(tvix/eval): unthunk empty lists and attribute setsVincent Ambo2-0/+8
Change-Id: Ie66cb1b163a544d45d113fd0f866286f230b0188 Reviewed-on: https://cl.tvl.fyi/c/depot/+/7960 Tested-by: BuildkiteCI Reviewed-by: grfn <grfn@gws.fyi>
2023-05-25 r/6204 feat(tvix/eval): implement unthunking in compilerVincent Ambo1-1/+22
This feature allows the compiler to detect situations where the created thunk is useless and can be merged into the parent chunk instead. The only case where the compiler does this initially is when statically optimising a select expression. For example, previously the expression `builtins.length` compiled into two thunks: 1. An "inner" thunk which contained an `OpConstant` that had the optimised `length` builtin in it. 2. An "outer" thunk which contained an `OpConstant` to access the inner thunk, and the trailing OpForce of the top-level program. With this change, the inner thunk is skipped completely and the outer chunk directly contains the `length` builtin access. This can be applied in several situations, some easier than others, and we will add them in as we go along. Change-Id: Ie44521445fce1199f99b5b17712833faea9bc357 Reviewed-on: https://cl.tvl.fyi/c/depot/+/7959 Tested-by: BuildkiteCI Reviewed-by: flokli <flokli@flokli.de>
2023-05-25 r/6203 feat(tvix/eval): implement Chunk::extend methodVincent Ambo1-1/+104
This method extends the contents of one chunk with that of another, effectively merging the thunks together. This will be used for the upcoming "unthunking" functionality. Change-Id: I6ad74232cd7f3eca198ed921e455205e00d76e6b Reviewed-on: https://cl.tvl.fyi/c/depot/+/7958 Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI
2023-05-25 r/6202 refactor(tvix/eval): stop borrowing &mut selfFlorian Klink1-12/+12
This does undo cl/8571. Change-Id: Ib14b4e7404f906e346304b6113860ae811afc94a Reviewed-on: https://cl.tvl.fyi/c/depot/+/8631 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su> Autosubmit: flokli <flokli@flokli.de>
2023-05-22 r/6173 refactor(tvix/eval): use &Path instead of PathBufFlorian Klink3-13/+13
This allows getting rid of some clones in eval/src/vm/generators.rs. Change-Id: I330390307d3bcfeef19c98954c753ee55b1ccee3 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8604 Autosubmit: flokli <flokli@flokli.de> Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su>
2023-05-22 r/6172 fix(tvix/eval): add path where useful to ErrorKind::IOFlorian Klink1-2/+10
These two places didn't add the path from the context to the ErrorKind, but simply relied on the impl From<std::io::Error> for tvix_eval::ErrorKind, which doesn't add the path. Change-Id: Ifc7dbbe305d24242b0705de1dea34e8923e9d2cb Reviewed-on: https://cl.tvl.fyi/c/depot/+/8603 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su> Autosubmit: flokli <flokli@flokli.de>
2023-05-22 r/6171 refactor(tvix/eval/io): use io::Error instead of tvix_eval errorsFlorian Klink2-49/+58
We didn't return anything useful other than ErrorKind::IO anyways. We can use io::ErrorKind::Unsupported for DummyIO. Fixes b/271. Change-Id: Icb231e9b38168e8b6fa473bfa405d160357b317f Reviewed-on: https://cl.tvl.fyi/c/depot/+/8602 Autosubmit: flokli <flokli@flokli.de> Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su>
2023-05-14 r/6140 feat(tvix/eval/io): allow &mut self in EvalIOFlorian Klink3-25/+29
It's okay if these calls mutate some internal state inside an implementation. Change-Id: I12bb11bde0310778c3da1275696bf7de058863a3 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8571 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su>
2023-05-12 r/6135 fix(tvix/eval): builtins.trace prints to stderrVincent Ambo1-1/+1
Change-Id: Icf577396035474d6977e627058aba5805c61985e Reviewed-on: https://cl.tvl.fyi/c/depot/+/8563 Tested-by: BuildkiteCI Autosubmit: tazjin <tazjin@tvl.su> Reviewed-by: flokli <flokli@flokli.de>
2023-05-11 r/6134 chore(tvix/*): bump to smol_str 0.2.0Florian Klink1-1/+1
Change-Id: Ic9ac1b6fecb564eafb41b265bf317cd385fdc170 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8560 Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI Autosubmit: flokli <flokli@flokli.de>
2023-03-31 r/6066 refactor(tvix/eval): improve representation of chunk/span mappingVincent Ambo1-25/+23
This switches out the previous compressed representation (count of instructions per span) with a representation where the chunk's span list stores the index of the first operation that belongs to a span, and finds the right span by using a binary search when looking them up. This improves the lookup complexity from O(n) to O(log n). This improvement was suggested and (mostly) implemented by GPT-4. I only fixed up some names and updated the logic for deleting spans (which it only did not do because I didn't tell it about that). The code was verified by producing a complex error before/after the change and ensuring that all spans in the error match exactly. Co-Authored-By: GPT-4 Change-Id: Ibfa12cc6973af1c9b0ae55bb464d1975209771f5 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8385 Reviewed-by: ezemtsov <eugene.zemtsov@gmail.com> Tested-by: BuildkiteCI Autosubmit: tazjin <tazjin@tvl.su>
2023-03-27 r/6045 refactor(tvix/eval): retain call frames when entering callsVincent Ambo1-6/+13
This grows the frame stack as the call stack grows, which yields *much* better user-facing error messages. I haven't measured the performance impact this has yet, for now I'm still just trying to add more information to errors and then cut down again where necessary. Change-Id: I89f058ef31979edacf4667775d460b60704ce4d7 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8334 Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI Autosubmit: tazjin <tazjin@tvl.su>
2023-03-22 r/6037 feat(tvix/eval): add Evaluation::strict to toggle top-level deepseqVincent Ambo4-4/+24
This makes it possible for callers to control whether they can receive partially evaluated values from an evaluation or not. We're actually flipping the default behaviour to non-strict top-level evaluation, which means that callers have to set `strict = true` on the Evaluation to get the previous behaviour. Change-Id: Ic048e9ba09c88866d4c3177d5fa07db11c4eb20e Reviewed-on: https://cl.tvl.fyi/c/depot/+/8325 Autosubmit: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2023-03-22 r/6036 fix(tvix/eval): print unevaluated thunks like Nix doesVincent Ambo1-0/+1
Change-Id: Ie4c563e933f571f45cb4f4efe650d1b65f119e8d Reviewed-on: https://cl.tvl.fyi/c/depot/+/8324 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org> Autosubmit: tazjin <tazjin@tvl.su>
2023-03-17 r/6027 fix(tvix/eval): use span of `set` for OpForce in attribute accessVincent Ambo1-2/+2
Emits the span of the `set` that is being accessed in the `force` operation of an attribute access. Looking at traces, it's a lot more useful to get information about *what* is being forced, as in cases like `foo.bar` it can be misleading to have an error highlight `bar`, when the error occured while forcing `foo` to be able to access `bar` in the first place. Change-Id: Id46ff28f20c67cb4971727ac52cc4811795cea2d Reviewed-on: https://cl.tvl.fyi/c/depot/+/8272 Reviewed-by: flokli <flokli@flokli.de> Autosubmit: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI
2023-03-17 r/6026 feat(tvix/eval): report all known spans on infinite recursionVincent Ambo3-16/+80
This reports the span 1. of the code within a thunk, 2. of the place where the thunk was instantiated, 3. of the place where the thunk was first forced, 4. of the place where the thunk was forced again, when yielding an infinite recursion error, which hopefully makes it easier to debug them. The spans are tracked in the ThunkRepr::Blackhole variant when putting a thunk under evaluation. Note that we currently have some loss of span precision in the VM loop when switching between frame types, so spans 3/4 are currently a bit wonky. Working on it. Change-Id: Icbd2a9df903d00e8c2545b3fc46dcd2a9e3e3e55 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8270 Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI Autosubmit: tazjin <tazjin@tvl.su>
2023-03-17 r/6025 feat(tvix/eval): track span of first force in a thunk blackholeVincent Ambo5-17/+48
This is step 1 towards being able to use all 4 spans that we know when dealing with infinite recursion. It tracks the span at which the force of a thunk was first requested when constructing a blackhole, so that we can highlight the spans of the first and second forces. These are actually the least relevant spans, but the easiest to put in place, more coming soon. Change-Id: I4c7e82f6211b98756439d4148a4191457cc46807 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8269 Autosubmit: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI Reviewed-by: flokli <flokli@flokli.de>
2023-03-17 r/6024 feat(tvix/eval): add generator "name" to NativeError kindVincent Ambo3-12/+29
This produces traces in which we can see what kind of native code was run. Note that these "names" are named after the generator message, so these aren't *really* intended for end-user consumption, but we can give them saner names later. Example: https://gist.github.com/tazjin/82b24e92ace8e821008954867ee05057 This already makes the traces a little easier to parse. Change-Id: Idcd601baf84f492211b732ea0f04b377112e10d0 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8268 Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI Autosubmit: tazjin <tazjin@tvl.su>
2023-03-17 r/6023 feat(tvix/eval): enrich errors with VM's frame stack informationVincent Ambo4-129/+242
When emitting an error at runtime, the VM will now use the new `NativeError` and `BytecodeError` error kinds (which just wrap inner errors) to create a set of diagnostics to emit. The primary diagnostic is emitted last, with `error` type (so it will be coloured red in terminals), the other ones will be emitted with `note` type, highlighting the causal chain. Example: https://gist.github.com/tazjin/25feba7d211702453c9ebd5f8fd378e4 This is currently quite verbose, and we can cut down on this further, but the purpose of this commit is to surface more information first of all before worrying about the exact display. Change-Id: I058104a178c37031c0db6b4b3e4f4170cf76087d Reviewed-on: https://cl.tvl.fyi/c/depot/+/8266 Autosubmit: tazjin <tazjin@tvl.su> Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI
2023-03-17 r/6022 fix(tvix/eval): use coerce_to_string in builtins.substringVincent Ambo3-1/+7
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
2023-03-17 r/6020 chore(tvix/eval): remove some dead codeVincent Ambo1-31/+0
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
2023-03-14 r/5994 docs(tvix/eval): suggested layout adjustment to VM loop diagramAdam Joseph1-11/+11
Change-Id: I5467cd66801ad8fe6c4ec0ae337763f1762cea1c Reviewed-on: https://cl.tvl.fyi/c/depot/+/8252 Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI Autosubmit: Adam Joseph <adam@westernsemico.com>
2023-03-14 r/5993 docs(tvix/eval): document inner workings of the new VM loopVincent Ambo1-45/+284
Change-Id: I8224bf039f739c401900b5a2ddc839810c87cf6e Reviewed-on: https://cl.tvl.fyi/c/depot/+/8226 Tested-by: BuildkiteCI Reviewed-by: Adam Joseph <adam@westernsemico.com>
2023-03-14 r/5992 chore(tvix): Generator{Request|Response} -> VM{Request|Response}Vincent Ambo3-130/+121
We settled on this being the most reasonable name for this construct. Change-Id: Ic31c45461a842f22aa05f4446123fe3a61dfdbc0 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8291 Tested-by: BuildkiteCI Autosubmit: tazjin <tazjin@tvl.su> Reviewed-by: raitobezarius <tvl@lahfa.xyz>
2023-03-13 r/5991 chore(tvix/eval): mark async functions which are called by the VMAdam Joseph3-0/+9
Given Rust's current lack of support for tail calls, we cannot avoid using `async` for builtins. This is the only way to avoid overflowing the cpu stack when we have arbitrarily deep builtin/interpreted/builtin/interpreted/... "sandwiches" There are only five `async fn` functions which are not builtins (some come in multiple "flavors"): - add_values - resolve_with - force, final_deep_force - nix_eq, nix_cmp_eq - coerce_to_string These can be written iteratively rather than recursively (and in fact nix_eq used to be written that way!). I volunteer to rewrite them. If written iteratively they would no longer need to be `async`. There are two motivations for limiting our reliance on `async` to only the situation (builtins) where we have no other choice: 1. Performance. We don't really have any good measurement of the performance hit that the Box<dyn Future>s impose on us. Right now all of our large (nixpkgs-eval) tests are swamped by the cost of other things (e.g. fork()ing `nix-store`) so we can't really measure it. Builtins tend to be expensive operations anyways (regexp-matching, sorting, etc) that are likely to already cost more than the `async` overhead. 2. Preserving the ability to switch to `musttail` calls. Clang/LLVM recently got `musttail` (mandatory-elimination tail calls). Rust has refused to add this mainly because WASM doesn't support, but WASM `tail_call` has been implemented and was recently moved to phase 4 (standardization). It is very likely that Rust will get tail calls sometime in the next year; if it does, we won't need async anymore. In the meantime, I'd like to avoid adding any further reliance on `async` in places where it wouldn't be straightforward to replace it with a tail call. https://reviews.llvm.org/D99517 https://github.com/WebAssembly/proposals/pull/157 https: //github.com/rust-lang/rfcs/issues/2691#issuecomment-1462152908 Change-Id: Id15945d5a92bf52c16d93456e3437f91d93bdc57 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8290 Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI Autosubmit: Adam Joseph <adam@westernsemico.com>
2023-03-13 r/5990 refactor(tvix/eval): reduce fetch{forced|captured}_with visibilityAdam Joseph1-22/+22
This commit moves fetch_forced_with and fetch_captured_with into the scope of their only caller (resolve_with). Change-Id: I9a8bc27228888729d591e8cb021c431b2b6468f5 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8289 Autosubmit: Adam Joseph <adam@westernsemico.com> Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI
2023-03-13 r/5989 feat(tvix/eval): rewrite nix_cmp_ordering to be nonrecursiveAdam Joseph1-45/+46
This rewrites nix_cmp_ordering as an iterative loop, which eliminates the extra pinned-boxing helper function. Change-Id: I33d0ecc913e02affd8fd4c7bc1c9ecfdf4c7deb9 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8288 Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI Autosubmit: Adam Joseph <adam@westernsemico.com>
2023-03-13 r/5988 chore(tvix/eval): prune some dependencies & featuresVincent Ambo2-15/+2
* We no longer need backtrace-on-stack-overflow, as we no longer overflow the stack with the recent eval refactorings. This was weird voodoo anyways, introduced earlier to debug some cases where stack overflows occured. * default features of genawaiter crate are not needed, as we don't use their proc macros Change-Id: I346fc5a18d7f117ee805909a8be8f535b96be76c Reviewed-on: https://cl.tvl.fyi/c/depot/+/8263 Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI Reviewed-by: raitobezarius <tvl@lahfa.xyz>
2023-03-13 r/5987 refactor(tvix/eval): reorder bytecode operations match by frequencyVincent Ambo1-265/+264
This reorders the operations in the VM's main `match` statement while evaluating bytecode according to the frequency with which these operations appear in some nixpkgs evaluations. I used raw data that looks like this: https://gist.github.com/tazjin/63d0788a78eb8575b04defaad4ef610d This has a small but noticeable impact on evaluation performance. No operations have changed in any way, this is purely moving code around. Change-Id: Iaa4ef4f0577e98144e8905fec88149c41e8c315c Reviewed-on: https://cl.tvl.fyi/c/depot/+/8262 Reviewed-by: raitobezarius <tvl@lahfa.xyz> Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI
2023-03-13 r/5985 docs(tvix/eval): fix reference to `Empty` message in a commentVincent Ambo1-1/+1
Change-Id: I3dc30cca33fbbd8e8686655635ee471f5937d9f8 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8257 Tested-by: BuildkiteCI Reviewed-by: raitobezarius <tvl@lahfa.xyz>
2023-03-13 r/5984 refactor(tvix/eval): rename VM::tail_call_value -> VM::call_valueVincent Ambo2-4/+4
The name of this was not accurate anymore after all the recent shuffling, as noted by amjoseph. Conceptual tail calls here only occur for Nix bytecode calling Nix bytecode, but things like a builtin call actually push a new native frame. Change-Id: I1dea8c9663daf86482b8c7b5a23133254b5ca321 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8256 Tested-by: BuildkiteCI Reviewed-by: raitobezarius <tvl@lahfa.xyz>
2023-03-13 r/5983 fix(tvix/eval): emit warnings from builtins.import againVincent Ambo3-14/+35
Wires up generator logic to emit warnings that already have spans attached again. Change-Id: I9f878cec3b9d4f6f7819e7c71bab7ae70bd3f08b Reviewed-on: https://cl.tvl.fyi/c/depot/+/8224 Tested-by: BuildkiteCI Reviewed-by: raitobezarius <tvl@lahfa.xyz>
2023-03-13 r/5982 fix(tvix/eval): more closely line up path resolution with cppnixVincent Ambo2-23/+51
... except now the tests fail, but at least it works Change-Id: I05e86c173f40533ae65548585c1ddaa200ac5235 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8214 Reviewed-by: raitobezarius <tvl@lahfa.xyz> Tested-by: BuildkiteCI
2023-03-13 r/5980 refactor(tvix/eval): VM struct no longer needs to be publicVincent Ambo2-2/+2
Change-Id: I93b485ddd280cc15fcbaecf4aed5fcd22e28a8a8 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8212 Reviewed-by: raitobezarius <tvl@lahfa.xyz> Tested-by: BuildkiteCI
2023-03-13 r/5979 fix(tvix/eval): implement cppnix JSON-serialisation semanticsVincent Ambo11-69/+136
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
generated by cgit-pink 1.4.1 (git 2.44.2) at 2024-11-21T13·39+0000