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2024-06-14 r/8270 chore(tvix/eval): move eval docs to tvix/docsFlorian Klink1-162/+0
Change-Id: I75b33c43456389de6e521b4f0ad46d68bc9e98f6 Reviewed-on: https://cl.tvl.fyi/c/depot/+/11809 Autosubmit: flokli <flokli@flokli.de> Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI
2024-03-12 r/7687 docs(tvix/eval): C++ Nix now has deduplicated inherit (from)sterni1-0/+3
Change-Id: Icf74c699130c2ab774973a7e98bc44ffba8c5ec2 Reviewed-on: https://cl.tvl.fyi/c/depot/+/11139 Tested-by: BuildkiteCI Autosubmit: sterni <sternenseemann@systemli.org> Reviewed-by: flokli <flokli@flokli.de>
2023-11-24 r/7052 docs(tvix/eval): optimization potential for inherit (from) exprssterni1-0/+19
Change-Id: Ibddaa111a5b7a86c42dbe153ae8e53f9a5601a54 Reviewed-on: https://cl.tvl.fyi/c/depot/+/10112 Tested-by: BuildkiteCI Reviewed-by: Adam Joseph <adam@westernsemico.com>
2023-06-20 r/6336 fix(tvix/eval): only finalise formal arguments if defaultingsterni1-0/+10
When dealing with a formal argument in a function argument pattern that has a default expression, there are two different things that can happen at runtime: Either we select its value from the passed attribute successfully or we need to use the default expression. Both of these may be thunks and both of these may need finalisers. However, in the former case this is taken care of elsewhere, the value will always be finalised already if necessary. In the latter case we may need to finalise the thunk resulting from the default expression. However, the thunk corresponding to the expression may never end up in the local's stack slot. Since finalisation goes by stack slot (and not constants), we need to prevent a case where we don't fall back to the default expression, but finalise anyways. Previously, we worked around this by making `OpFinalise` ignore non-thunks. Since finalisation of already evaluated thunks still crashed, the faulty compilation of function pattern arguments could still cause a crash. As a new approach, we reinstate the old behavior of `OpFinalise` to crash whenever encountering something that is either not a thunk or doesn't need finalisation. This can also help catching (similar) miscompilations in the future. To then prevent the crash, we need to track whether we have fallen back or not at runtime. This is done using an additional phantom on the stack that holds a new `FinaliseRequest` value. When it comes to finalisation we check this value and conditionally execute `OpFinalise` based on its value. Resolves b/261 and b/265 (partially). Change-Id: Ic04fb80ec671a2ba11fa645090769c335fb7f58b Reviewed-on: https://cl.tvl.fyi/c/depot/+/8705 Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI Autosubmit: sterni <sternenseemann@systemli.org>
2023-02-03 r/5831 refactor(tvix/eval): statically resolve select from constant attrsVincent Ambo1-10/+4
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>
2023-01-25 r/5758 docs(tvix/eval): builtins.add is not equivalent to +sterni1-3/+3
While it is in the given example, i.e. for integer addition, to claim that they are equivalent is a bit misleading: builtins.add is less overloaded than +, i.e. builtins.add "foo" "bar" will fail whereas "foo" + "bar" performs string concatenation. Change-Id: Ib52d530d1ab289b367565b286f06a76dd518d4fb Reviewed-on: https://cl.tvl.fyi/c/depot/+/7929 Autosubmit: sterni <sternenseemann@systemli.org> Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI
2023-01-21 r/5721 refactor(tvix/eval): administer antidote for poisonAdam Joseph1-2/+2
The codebase contains a lot of complexity and odd roundabout handling for shadowing globals. I'm pretty sure none of this is necessary, and all of it disappears if you simply make the globals part of the ordinary identifier resolution chain, with their own scope up above the root scope. Then the ordinary shadowing routines do the right thing, and no special cases or new terminology are required. This commit does that. Note by tazjin: This commit was originally abandoned when Adam decided not to take away reviewer bandwidth for this at the time (eval was still in a much earlier stage). As we've recently done some significant refactoring of globals initialisation this came up again, and it seems we can easily cover the use-cases of the poison tracking in other ways now, so I've rebased, updated and resurrected the CL. Co-Authored-By: Vincent Ambo <tazjin@tvl.su> Signed-off-by: Adam Joseph <adam@westernsemico.com> Change-Id: Ib3309a47a7b31fa5bf10466bade0d876b76ae462 Reviewed-on: https://cl.tvl.fyi/c/depot/+/7089 Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI Reviewed-by: flokli <flokli@flokli.de>
2022-12-29 r/5530 docs(tvix/eval): sketch in place list/attr set update ideasterni1-0/+24
Change-Id: Ic7debbd8cbd3acdf5f3947288f2aa2964bd163a0 Reviewed-on: https://cl.tvl.fyi/c/depot/+/7660 Autosubmit: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su>
2022-10-28 r/5217 docs(tvix/eval): add "intern literals" to future optimisationsAdam Joseph1-0/+6
Signed-off-by: Adam Joseph <adam@westernsemico.com> Change-Id: I460230863de853ca5248733bc977d4780b216f36 Reviewed-on: https://cl.tvl.fyi/c/depot/+/7096 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4821 docs(tvix/eval): propose builtin "inlining" optimisationsterni1-0/+18
Change-Id: I96a187792a1fd48cffd6b56ec22347aee8cae3af Reviewed-on: https://cl.tvl.fyi/c/depot/+/6526 Autosubmit: sterni <sternenseemann@systemli.org> Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI
2022-09-11 r/4820 docs(tvix/eval): mention `?` and `or` for builtins optimisationsterni1-1/+3
Change-Id: Ifaa6da345d408a69ce46d6a0e7483352715c75bd Reviewed-on: https://cl.tvl.fyi/c/depot/+/6525 Autosubmit: sterni <sternenseemann@systemli.org> Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI
2022-09-11 r/4803 docs(tvix/eval): add optimisation note on eliminating `with` thunksVincent Ambo1-6/+9
Change-Id: I18d50ac8e157929a027f8bf284e65f1eb8950d5a Reviewed-on: https://cl.tvl.fyi/c/depot/+/6488 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-08 r/4748 refactor(tvix/eval): return call frame result from VM::callVincent Ambo1-0/+16
Previously, "calling" (setting up the VM run loop for executing a call frame) and "running" (running this loop to completion) were separate operations. This was basically an attempt to avoid nesting `VM::run` invocations. However, doing things this way introduced some tricky bugs for exiting out of the call frames of thunks vs. builtins & closures. For now, we unify the two operations and always return the value to the caller directly. For now this makes calls a little less effective, but it gives us a chance to nail down some other strange behaviours and then re-optimise this afterwards. To make sure we tackle this again further down I've added it to the list of known possible optimisations. Change-Id: I96828ab6a628136e0bac1bf03555faa4e6b74ece Reviewed-on: https://cl.tvl.fyi/c/depot/+/6415 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4746 docs(tvix/eval): add notes for builtins access optimisationVincent Ambo1-0/+10
Change-Id: Iadbfbe2864ae42fe5492ef3ede0925baee4872b2 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6413 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-06 r/4652 docs(tvix/eval): start a document on known optimisation potentialVincent Ambo1-0/+57
Change-Id: I9bc41e57e1cfdf536d7b9048bac2e7aff1ee2ffa Reviewed-on: https://cl.tvl.fyi/c/depot/+/6313 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
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