Commit graph

127 commits

Author SHA1 Message Date
Vincent Ambo
e86acd3212 feat(tvix/eval): implement legacy let syntax
... and emit a warning if anyone decides to use.

Change-Id: Iaa6fe9fa932340e6d0fa9f357155e78823702576
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6611
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-16 18:13:26 +00:00
Vincent Ambo
20230e1e2d feat(tvix/eval): implement recursive attribute sets
Yep.

This is kind of ugly right now. The idea is that the recursive_scope
compilation function is used for recursive sets as well by emitting
the keys. The rest of the logic is pretty much identical.

There is quite a lot of code here that can be cleaned up (duplication
between attrs and let, duplication inside of the recursive scope
compilation function etc.), but I'd like to get it working first and
then make it nice.

Note that nested keys are *not* supported yet.

Change-Id: I45c7cdd5f0e1d35fd94797093904740af3a97134
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6610
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-16 18:12:13 +00:00
Vincent Ambo
a7e280ec00 refactor(tvix/eval): introduce a type for tracking bindings
This type is used in the list temporarily populated by the *second*
pass over all identifiers in a recursive scope. This first pass only
serves to make all bindings known to the compiler, without populating
their values yet.

Having a type here is going to be useful once we implement `rec`,
which needs to thread through slightly more information.

Change-Id: Ie33e0f096c5fcb6c864c991255466748b6f0d1eb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6609
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-16 18:12:13 +00:00
Vincent Ambo
1cf07051cb refactor(tvix/eval): extract recursive scope logic into a helper
This needs to be reused between let & `rec` attrs.

Change-Id: I4a3bb90af4be32771b0f9e405c19370e105c0fef
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6608
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-16 18:02:33 +00:00
Vincent Ambo
01a239c955 refactor(tvix/eval): move compile_inherit_attrs to compiler::attrs
Plain move, no other changes.

Change-Id: Ic4f89709f5c2cbc03182a848af080c820e39a0fd
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6607
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-16 18:02:33 +00:00
Vincent Ambo
6cc9d298aa refactor(tvix/eval): explicitly construct attrs in phases
This makes the phases of attribute set construction that Nix has very
explicit (inherits, static keys, dynamic keys).

This change focuses on the split between dynamic/static keys by
collecting all dynamic ones while compiling the static ones, and then
phasing them in afterwards. It's possible we also need to do some
additional splitting inside of the inherits.

Change-Id: Icae782e2a5c106e3ce0831dda47ed81c923c0a42
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6530
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-16 18:02:33 +00:00
sterni
0595870341 refactor(tvix/eval): don't move parts Vec in compile_str_parts
This allows us to get rid of the count local variable which was a bit
confusing. Calling parts.len() multiple times is fine, since the length
doesn't need to be computed.

Change-Id: I4f626729ad1bf23a93cb701385c3f4b50c57456d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6584
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
2022-09-15 15:52:53 +00:00
sterni
4eb33e82ff fix(tvix/eval): coerce string interpolation parts to string
With this puzzle piece of string compilation in place, `compile_str`
becomes less redundant, as every part now needs to be compiled the same.
The thunking logic becomes a bit trickier, since we need to thunk even
in the case of `count == 1` if the single part is interpolating.
Splitting the inner (shared) code in a separate function turned out to
be easier for making rustc content.

Change-Id: I6a554ca599926ae5907d7acffce349c9616f568f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6582
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
2022-09-15 15:52:53 +00:00
sterni
bcd7e520f0 fix(tvix/eval): thunk string interpolation
If we have multiple string parts, we need to thunk assembling the
string. If we have a single literal, it is strict (like all literals),
but a single interpolation part may compile to a thunk, depending on how
the expression inside is compiled – we can avoid forcing to early here
compared to the previous behavior.

Note that this CL retains the bug that `"${x}"` is erroneously
translated to `x`, implying e.g. `"${12}" == 12`.

The use of `parts.len()` is unproblematic, since normalized_parts()
builds a `Vec` instead of returning an iterator.

Change-Id: I3aecbfefef65cc627b1b8a65be27cbaeada3582b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6580
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
2022-09-15 15:52:53 +00:00
sterni
6d53fb6c52 fix(tvix/eval): force exprs inside string interpolation
The expression inside ${…} may return arbitrary values, including
thunks, so we need to make sure to force them just in case.

Change-Id: Ic11ba00c4c92a10a83becd91233db5f57f6e59c8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6541
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
2022-09-13 22:06:28 +00:00
Vincent Ambo
477015cfe3 refactor(tvix/eval): point OpPushWith span at namespace
Pointed out by sterni in cl/6395

Change-Id: I2dda2bb11fef702df05fd7a4fd93b9e717a85dad
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6567
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-13 14:41:57 +00:00
Vincent Ambo
62623ef46c refactor(tvix/eval): point OpAssert span at condition
This is more useful than pointing it at the entire assert expression,
as that includes the body as well which is not going to be relevant in
the error.

Pointed out by sterni in cl/6391

Change-Id: I95a5d1edf90df65e7fa53d4d04502afd6e99e89a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6566
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-13 14:41:57 +00:00
Vincent Ambo
c28ecbee97 refactor(tvix/eval): encapsulate scope_depth in compiler::scope
This field no longer needs to be directly accessible by the compiler.

Addresses a sterni lint from cl/6466

Change-Id: I5e6791943d7f0ab3d9b7a30bb1654c4a6a435b1f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6564
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-13 14:41:57 +00:00
Vincent Ambo
0f59fe6601 feat(tvix/eval): implement initial fancy formatting for errors
This very closely follows the way it's done for warnings, but errors
have a lot more information available in some cases which we do not
surface yet.

Note also that due to requiring the `CodeMap`, this is not yet called
from eval.rs as the way that is threaded through needs to be
refactored, so only the method for reporting these errors as strings
is implemented so far.

Next steps for this will be to add a generic diagnostics module that
reduces some of the boilerplate for this between warnings & errors,
and which will also give us a good point in the future to switch to a
fancier diagnostics crate.

Change-Id: If6bb209f8e7a568d866e516a90335b9b2afbf66d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6534
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
2022-09-13 14:41:57 +00:00
Vincent Ambo
2fe193ce41 chore(tvix/eval): address current clippy lints
Change-Id: I76326c20a525044e89d3cd1392a29faa3414ca04
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6529
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-11 21:13:24 +00:00
Vincent Ambo
1844c788f5 refactor(tvix/eval): remove todo!() calls in compiler
It is impossible for tvixbolt to recover from panics, so the user
experience of typing an expression using an unsupported feature was
that it would get sad and stop responding to input.

Instead, raise a normal value-level error of a new variant and
continue where possible.

Change-Id: Ibe016c92cacb87b85095c0f83758eddc6468053e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6528
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 21:13:24 +00:00
Vincent Ambo
677d4e6881 fix(tvix/eval): reduce scope depth in scope module
Change-Id: If32f9e4c9212f20a39baa15d479ff1387c17570d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6500
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:26:23 +00:00
Vincent Ambo
a0acbfa470 refactor(tvix/eval): refactor methods for parsing static idents
Refactors the methods used for determining whether an identifier in a
binding (i.e. an `rnix::Attr` node) is a static string, and extracting
it.

Previously all uses of this logic were for `let`-expressions, where
dynamic attributes are always an error. However, we need the same
logic to properly implement the phase separation of attribute set
compilation.

To facilitate this, the actual core logic of these methods now return
`Option`, and are only converted to errors in cases where the errors
are actually required.

Change-Id: Iad7826eff2cb428182521c6f92276310edeae1eb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6498
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:26:23 +00:00
Vincent Ambo
39509683a2 refactor(tvix/eval): move attrset-related code to compiler::attrs
There's about to be a lot more code for attrsets (hopefully
temporarily as part of an expand&contract cycle), while nested
attribute logic is being refactored in preparation for recursive
attribute sets.

This does not change any functionality.

Change-Id: I667565cd810ca7d9046120d1721c2ceb9095550b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6497
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:26:23 +00:00
sterni
7046604cfe fix(tvix/eval): place plain inherits in correct stack slots
We need to make sure that we compile all plain inherits in a let
expression before declaring any other locals. Plain inherits are special
in the sense that they can never be recursive, instead resolving to a
higher scope. Thus we need to compile their value, before declaring
them. If we don't do that, before any other local can be declared,
we cause a situation where the plain inherits' values are placed into
other locals' stack slots.

Note that we can't integrate the plain inherit compilation into the
regular 2-3 phase model where we defer the compilation of the value or
we'd compile `let inherit x; in …` as `let x = x; in …`.

Change-Id: I951d5df3c9661a054e12401546875f4685b5bf08
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6496
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:26:23 +00:00
sterni
240d90aa8a fix(tvix/eval): wrap asserts in a thunk
As the new test case demonstrates, asserts need to be evaluated lazily.

Change-Id: I808046722c5a504e9497855ca5026d255c7a4c34
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6494
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:26:23 +00:00
sterni
4d8f35353b fix(tvix/eval): declare let inherit (from) locals before compiling
The recent change that split declaration of let based locals and the
compilation of their values did not touch locals bound by inherit in
let. These were previously declared and compiled immediately before
starting to work on the other locals introduced in a let.

In the case of plain inherits, this behavior is kept in this change,
because there's nothing wrong with it: The value of a plain inherit will
always resolve to a higher scope, either statically or dynamically.

Since inherit (from) expression might refer to other locals bound in the
same let, we need to handle them in the same three steps as ordinary let
based locals:

1. We need to declare the (uninitialised) locals.

2. We need to compile the expression that obtains their value. For this,
   we create a new thunk, since the from expression may very well return
   a thunk which we need to force before selecting the value we are
   interested in.

3. Thunks need to be finalised.

For 1., we create an extra pass over the inherits that already declares
and initialises plain inherits and notes inherit (from) expressions in
the entries vector after declaring them. 2. only needs a bit of adapting
to create the thunks for selecting if appropriate, the rest of the
existing code can be reused.

Change-Id: Ie4ac1c0f9ffcbf7c07c452036aa8e577443af773
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6490
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
2022-09-11 12:26:23 +00:00
Vincent Ambo
627dfabef1 fix(tvix/eval): thunk all uses of with
With this all other "weird scope" logic starts working for `with` as
well.

Change-Id: I0ea1d8c5fbd9cec5084bd574224f77b71ff2b487
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6487
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:26:23 +00:00
Vincent Ambo
07ea30370e refactor(tvix/eval): capture entire with_stack in upvalues
This completely rewrites the handling of "dynamic upvalues" to,
instead of resolving them at thunk/closure instantiation time (which
forces some values too early), capture the entire with stack of parent
contexts if it exists.

There are a couple of things in here that could be written more
efficiently, but I'm first working through this to get to a bug
related to with + recursion and the code complexity of some of the
optimisations is distracting.

Change-Id: Ia538e06c9146e3bf8decb9adf02dd726d2c651cf
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6486
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:26:23 +00:00
Vincent Ambo
fd14eefed6 fix(tvix/eval): correctly account for slots during list construction
Similarly to attribute sets, list elements can be arbitrary
expressions and their (temporary) stack slots during construction must
be accounted for by the compiler.

Change-Id: I3b6f7927860627fd867c64d0cab9104fd636d4f5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6470
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:16:46 +00:00
Vincent Ambo
33059de431 refactor(tvix/eval): cut down one iteration over locals array
Caught by sterni in cl/6339

Change-Id: I2f2cd746114f14854cf599a7223a42a3e8ebe4fc
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6469
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:04:27 +00:00
Vincent Ambo
f68c76d07d fix(tvix/eval): account for attrset temporaries during construction
The temporaries left on the stack as operands to `OpAttrs` must be
accounted for in the locals array in order for operations within them
to receive correct slots.

Some test cases that were previously broken have been added.

Change-Id: Ib52b629bbdf7931f63fd45a45af1073022da923c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6468
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:04:27 +00:00
Vincent Ambo
12acb1e237 refactor(tvix/eval): add initialised arg to declare_phantom
There are more upcomming uses of declare_phantom where this will come
in handy to avoid some code bloat.

Change-Id: I75cad8caf14511c519ab2f56e87e99bcbf0a082e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6467
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:04:27 +00:00
Vincent Ambo
9da99af860 refactor(tvix/eval): encapsulate scope cleanup logic in module
Moves the logic for removing tracked locals from a given scope from
the compiler's locals list, and leaves only the actual
compiler-related stuff (emitting warnings, cleaning up locals at
runtime) in the compiler itself.

Change-Id: I9da6eb54967f0a7775f624d602fe11be4c7ed5c4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6466
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:04:27 +00:00
Vincent Ambo
27e69503a7 fix(tvix/eval): avoid forcing with-target until absolutely necessary
Change-Id: I00efbbb8b9d3d22f32becf0919c6adf1be8b4b69
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6465
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:04:27 +00:00
Vincent Ambo
bb34665abd refactor(tvix/eval): extract attribute set inherit into helper
This will be re-used between the code paths for
recursive/non-recursive sets, and it might even be possible to unify
it with the logic for compiling `let inherit ...`.

Change-Id: I960a061048ac583a6e932e11ff6e642d9fc3093e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6464
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:04:27 +00:00
Vincent Ambo
f86327beac feat(tvix/eval): implement "formals" function parameters
The comment explains how this works fairly well.

Note that this does not yet have the ability to check "closed
formals", i.e. without an ellipsis Tvix will *NOT* fail if unexpected
attribute set keys are provided.

Change-Id: I0d2b77e893243093d2789baa57f876d35d0a32ff
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6463
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-11 10:32:10 +00:00
Vincent Ambo
06909f1821 fix(tvix/eval): fix doc comment syntax where applicable
As pointed out by grfn on cl/6091

Change-Id: I28308577b7cf99dffb4a4fd3cc8783eb9ab4d0d6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6460
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-10 21:57:13 +00:00
Vincent Ambo
6bbe7589c5 feat(tvix/eval): optimise tail calls in emitted chunks
When the last instruction in a chunk is OpCall, make it an OpTailCall instead.

Change-Id: I2c80a06ee85e4abf545887b1a79b6d8b5e6123e9
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6458
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-10 21:57:13 +00:00
Vincent Ambo
8ee4d6d5db feat(tvix/eval): implement DisassemblingObserver for compiler
This type implements an observer that is called whenever the compiler
emits a chunk (after the toplevel, thunks, or lambdas) and prints the
output of the disassembler to its internal writer.

This replaces half of the uses of the `disassembler` feature, which
has been removed from the Cargo configuration.

Note that at this commit runtime tracing is not yet implemented as an
observer.

Change-Id: I7894ca1ba445761aba4ad51d98e4a7b6445f1aea
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6449
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-09 21:10:10 +00:00
Vincent Ambo
abdfa7459e feat(tvix/eval): thunk binary operations and select expressions
With this, most cases of `fix` in attribute sets will work correctly.
A simple test exercising both has been added.

Change-Id: I70fd431177bb6e48ecb33a87518b050c4c3d1c09
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6437
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 20:17:26 +00:00
Vincent Ambo
48d5f4fd57 feat(tvix/eval): print lambda memory adresses in disassembler
This makes it easier to track exactly which lambda is which when
inspecting e.g. the concrete representation of a thunk.

At runtime all lambdas live in an Rc. To make this print the right
address, the construction of these Rcs had to be moved up right to the
point where the lambda is first emitted (and disassembled).

Change-Id: I6070e6c8ac55f0bd697966c4e7c5565c20d19106
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6435
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 20:17:26 +00:00
Vincent Ambo
fc1c50498e feat(tvix/eval): thunk function applications
Change-Id: I18065ed234ec104ac74d0e1c2d0937c2d78ca7db
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6433
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 20:17:26 +00:00
Vincent Ambo
e129ce15d7 feat(tvix/eval): thunk creation of lists
Change-Id: I84b68c5d002ec613d278315bbf49e9839f0fe8e8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6432
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 20:17:26 +00:00
Vincent Ambo
09eaa0d4ae fix(tvix/eval): address current clippy & grfn lints
Change-Id: I65c6feb9f817b5b367d37204a1f57acfe4100d97
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6430
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 20:17:26 +00:00
Vincent Ambo
fe047885d7 fix(tvix/eval): consider local depth when deciding to defer
Deferred local upvalues can *only* occur at the same depth as the
thing that is closing over them, but there are various situations with
scope nesting where the actual stack indexes of the local and the
closer look like a deferred value is being accessed.

To fix this, simply compare the depth as well.

Change-Id: Ice77424cc87ab0a2c4f01379e68d4399a917b12b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6429
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 20:17:26 +00:00
Vincent Ambo
0af1df4be2 refactor(tvix/eval): clean up logic in Compiler::end_scope
The condition here was extremely hard to read prior to this change.

As the locals vector is now guaranteed to never be empty (there is
always at least a phantom for the current chunk's root expression),
the logic here can be simplified to just dropping tailing locals
entries while their depth matches that of the scope being closed.

Change-Id: I24973e23bc2ad25e62ece64ab4d8624e6e274c16
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6427
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 19:54:02 +00:00
Vincent Ambo
23f248b530 fix(tvix/eval): set up root stack slot in closures & thunks
Similar to setting up a phantom slot when compiling the root value of
a file, closures and thunks need to have a phantom stack slot for the
root of the expression yielded by their thunk to make all accounting
work correctly.

The tricky thing here is that closures & thunks *escape* their inner
lambda context (that's the point!), so the functions emitting them
need to know both the *inner* slot (to resolve everything correctly
while compiling the slot) and the *outer* slot (to correctly emit
instructions for closing over upvalues).

Change-Id: I62ac58e2f639c4b9e09cc702bdbfd2373e985d7f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6426
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 19:54:02 +00:00
Vincent Ambo
4e24bd56b4 fix(tvix/eval): only pop initialised locals when closing scopes
This avoids emitting OpPop instructions for locals that only existed
virtually (as uninitialised phantoms).

Change-Id: I8105afcca80c3f7b7ef93ce5e2f0d08a93f4ad27
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6425
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 19:54:02 +00:00
Vincent Ambo
ecbd7c6ca1 fix(tvix/eval): ensure that root stack slot actually exists
Instead of using a sentinel LocalIdx which potentially points to a
value in the locals stack that does not actually exist, set up an
initial uninitialised phantom value representing the result of the
root expression.

Change-Id: I82ea774daab83168020a3850bed57d35ab25c7df
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6424
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 19:54:02 +00:00
Vincent Ambo
f8575fcd74 fix(tvix/eval): compare *stack* slots when deciding whether to defer
When deciding whether an upvalue needs to have a deferred resolution
step, the *stack* indexes should be compared - not the locals indexes.

The results are almost always the same, but there are tricky
situations where this can cause errors.

It's difficult to reproduce these errors in isolation, as they depend
on other scope behaviour, so this is one in a series of commits to
address the combination of issues which will gain some tests at the
end.

Change-Id: Iaa400b8d9500af58f493ab10e4f95022f3b5dd21
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6423
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 19:54:02 +00:00
Vincent Ambo
9973ddfcba refactor(tvix/eval): refactor locals to use an enum for phantoms
Instead of using sentinel values and an additional bool, this tracks
the identifier of a local as an enum that is either a statically known
name, or a phantom.

To make this work correctly some more locals related logic has been
encapsulated in the `scope` module, which is a good thing (that's the
goal).

Phantom values are now not initialised by default, but the only
current call site of phantoms (`with` expression compilation) performs
the initialisation right away.

This commit changes no actual functionality right now, but paves the
way for fixing an issue related to `let` bodies.

Change-Id: I679f93a59a4daeacfe40f4012263cfb7bc05034e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6421
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 13:36:26 +00:00
Vincent Ambo
7bc6e5984d refactor(tvix/eval): always pass slot to compiler methods
The slot is now always known (at the root of the file it is simply
stack slot 0 once the scope drops back down to 0), so it does not need
to be wrapped in an `Option` and accessed in cumbersome ways anymore.

Change-Id: I46bf67a4cf5cb96e4874dffd0e3fb07c551d44f0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6420
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 13:36:26 +00:00
Vincent Ambo
cc526a2c87 feat(tvix/eval): thread codemap through to disassembler
If the disassembler feature is enabled, make sure that an Rc of the
codemap is available through the chunk.

Change-Id: I700f27ab665a704f73457b19bd2d7efc93828a16
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6414
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 12:53:08 +00:00
Vincent Ambo
5ee89bcf5c fix(tvix/eval): inherit scope poisoning data in nested contexts
Scope poisoning must be inherited across lambda context boundaries,
e.g. if an outer scope has a poisoned `null`, any lambdas defined on
the same level must reference that poisoned identifier correctly.

Change-Id: I1aac64e1c048a6f3bacadb6d78ed295fa439e8b4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6410
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 07:59:15 +00:00