Commit graph

434 commits

Author SHA1 Message Date
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
William Carroll
f859751c6a feat(tvix/eval): Support builtins.bitXor
Bitwise "exclusive-or" on integers.

Change-Id: I90a0a15afb3a58662d70e82ea14e48b877476e04
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6550
Autosubmit: wpcarro <wpcarro@gmail.com>
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
2022-09-15 21:53:10 +00:00
William Carroll
031ca653a3 feat(tvix/eval): Support builtins.bitOr
Bitwise `or` on integers.

Change-Id: I45b0897331d1a9b6840f9d0feedcf10acc67fcec
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6549
Autosubmit: wpcarro <wpcarro@gmail.com>
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
2022-09-15 21:47:09 +00:00
William Carroll
f5f6bd319d feat(tvix/eval): Support builtins.bitAnd
Bitwise `and` on integers.

Change-Id: I9f2a9182a057af26906683acd97a40dfabbdded8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6548
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
2022-09-15 21:41:08 +00:00
William Carroll
5a6d9ee1a0 feat(tvix/eval): Support builtins.attrValues
:)

Change-Id: Idf170b506ed6fab035b1e6f61055fee02e5c9be8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6547
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: wpcarro <wpcarro@gmail.com>
Tested-by: BuildkiteCI
2022-09-15 21:13:03 +00:00
sterni
067f2b16f6 feat(tvix/eval): implement Value::coerce_to_path()
This function is necessary for all builtins that expect some form of
path as an argument. It is merely a wrapper around coerce_to_string that
can shortcut if we already have a path. The absolute path check is done
in the same way as in C++ Nix for compatibility, although it should
probably be revised in the long term (think about Windows, for example).

Since coercing to a path is not an operation possible in the language
directly, this function can live in the builtins module as the only
place it is required.

Change-Id: I69ed5455c00d193fea88b8fa83e28907a761cab5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6574
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
2022-09-15 20:58:00 +00:00
William Carroll
e834a2cbc4 feat(tvix/eval): Support builtins.attrNames
Define `.len()` method on `NixAttrs` to preallocate the capacity of the result
vector.

Also anchor an errant comment to its context (I think).

Change-Id: I268f15025d453d7b3ae1146558c80e51433dd2a8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6546
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: wpcarro <wpcarro@gmail.com>
Tested-by: BuildkiteCI
2022-09-15 20:37:57 +00:00
William Carroll
85b3f17007 feat(tvix/eval): Support builtins.head
TL;DR:
- support `builtins.head`
- define `ErrorKind::IndexOutOfBounds` and canonical error code
- support basic unit tests

Change-Id: I859107ffb4e220cba1be8c2ac41d1913dcca37ff
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6544
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
2022-09-15 16:48:24 +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
da1d71a4e8 feat(tvix/eval): implement correct toString behavior
Implement C++ Nix's `EvalState::coerceToString` minus some of the Path
/ store handling. This is currently only used for `toString` which does
all possible coercions, but we've already prepared the weaker coercion
variant which is e.g. used for builtins that expect string arguments.

`EvalState::coerceToPath` is still missing for builtins that need a
path, but it'll be easy to build on top of this.

Change-Id: I78d15576b18921791d04b6b1e964b951fdef22c6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6571
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
2022-09-15 11:47:30 +00:00
sterni
162e21f2bb fix(tvix/eval): force left argument of ? before checking for attrs
OpAttrsIsSet and OpAttrsTrySelect will fail silently if the attribute
set value on the stack is actually a thunk, so we need to make sure to
force at every step of the way.

Emitting the force instructions in the compiler because it is easier to
add, but maybe the VM should do this when handling the relevant opcodes?
Comments welcome.

Change-Id: I65c5ef348d59b2d07c9bb06abb24f9f3e6a0fdb2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6540
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
2022-09-13 22:06:29 +00:00
sterni
7e625afc59 fix(tvix/eval): force value in builtins.typeOf
This prevents Nix programs to observe the "internal" type of thunks.
Possibly .type_of() is also an area of the runtime where we should panic
if "internal" would ever be returned.

Change-Id: I9f358044c48ad64896fb6a1b1a42f00a29efac00
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6539
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
2022-09-13 22:06:29 +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
f69e83ae7b refactor(tvix/eval): cover all Value variants in force_for_output
Avoids accidentally dropping one on the floor if we add more, pointed
out by sterni in cl/6372

Change-Id: Ib7bb0ce9c8331c8337003d20c4d5240dfae1c32a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6570
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-13 14:41:57 +00:00
Vincent Ambo
3e188d4f8e fix(tvix/eval): add branch for directly comparing two thunks
Pointed out by sterni in cl/6370

Change-Id: I324d8049a2702ced8f30ad43a64d63ae79dd0eab
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6569
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-13 14:41:57 +00:00
Vincent Ambo
6fdf55a975 fix(tvix/eval): use fragment span for OpAttrsSelect
Pointed out by sterni in cl/6389

Change-Id: I648056a760266a8cfd7adcdc478c7ff2132991f7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6568
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-13 14:41:57 +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
30de72fefb chore(tvix/eval): do not inherit scope depth in new scopes
This is no longer required, resolution is now more sane. Pointed out
by sterni in cl/6422.

Change-Id: Icc8983c648f864e66813948df6e2d4bad6a7f312
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6565
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
268605140e fix(tvix/eval): address current clippy lints
Change-Id: I5288849d0e93511b0b5664fa92f1c6882e4a1356
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6563
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-13 14:41:57 +00:00
Vincent Ambo
d5ee893fb1 refactor(tvix/eval): use CodeIdx wrapper for instruction pointer
As suggested by sterni in cl/6453.

Change-Id: I3cf80d97c11fd7d085ab510f6be4b5f937c791ec
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6562
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
4f67cf221a feat(tvix/eval): implement initial fancy display for warnings
This implements an initial fancy display for warnings emitted by the
tvix compiler, using the codemap_diagnostic crate.

Each warning variant has an associated message, and optionally an
associated annotation for the span displayed to the user.

In theory we could get a lot more fancy with the display for specific
variants if needed (e.g. re-parse the AST and actually add multiple
semantic spans based on context), but this is already a good start.

Example:

  tvix-repl> let toString = https://tvl.fyi; in let inherit toString; in ({}: 42) rec {}
  warning[W004]: declared variable 'toString' shadows a built-in global!
   --> [tvix-repl]:1:5
    |
  1 | let toString = https://tvl.fyi; in let inherit toString; in ({}: 42) rec {}
    |     ^^^^^^^^ variable declared here

  warning[W001]: URL literal syntax is deprecated, use a quoted string instead
   --> [tvix-repl]:1:16
    |
  1 | let toString = https://tvl.fyi; in let inherit toString; in ({}: 42) rec {}
    |                ^^^^^^^^^^^^^^^

  warning[W002]: inherited variable already exists with the same value
   --> [tvix-repl]:1:40
    |
  1 | let toString = https://tvl.fyi; in let inherit toString; in ({}: 42) rec {}
    |                                        ^^^^^^^^^^^^^^^^^

  warning[W999]: feature not yet implemented in tvix: recursive attribute sets
   --> [tvix-repl]:1:70
    |
  1 | let toString = https://tvl.fyi; in let inherit toString; in ({}: 42) rec {}
    |                                                                      ^^^^^^

  warning[W999]: feature not yet implemented in tvix: closed formals
   --> [tvix-repl]:1:62
    |
  1 | let toString = https://tvl.fyi; in let inherit toString; in ({}: 42) rec {}
    |                                                              ^^

  warning[W003]: variable 'toString' is declared, but never used:
   --> [tvix-repl]:1:5
    |
  1 | let toString = https://tvl.fyi; in let inherit toString; in ({}: 42) rec {}
    |     ^^^^^^^^ variable declared here

  => 42 :: int

These are coloured when output to a terminal.

Change-Id: If315648a07e333895db4ae1d0915ee2013806585
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6532
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
2022-09-13 11:12:29 +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
43ec68d5ae fix(tvix/eval): pass correct slot when compiling attr values
Change-Id: I90722d59dea4c7694eb5a7cf505db31196ba6c6c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6501
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:26:23 +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
675bd36ea5 feat(tvix/eval): add Chunk::pop_op method
This is used to drop an already emitted operation from a chunk again
and clean up its span tracking. This is required in cases where the
compiler has to backtrack.

Change-Id: I8112da9427688bb2dec96a2ddd12390f6e9734c3
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6499
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
bb1adbb05b test(tvix/eval): add test for mutually recursive let bindings
This test shows that let bindings' dependencies can form a cyclical
graph, so we need to use thunking to break this cycle.

Change-Id: I2a4de71fd7024f3d3d1166154784139a82f39411
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6495
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
f95b23d743 test(tvix/eval): test “useful” plain inherits
Change-Id: Ic4700f0618a393e45a2ee7c70045edff97e30c49
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6493
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
d75b207a63 refactor(tvix/eval): introduce Upvalues struct in closures & thunks
This struct will be responsible for tracking upvalues (and is a
convenient place to introduce optimisations for reducing value clones)
instead of a plain value vector.

The main motivation for this is that the upvalues will have to capture
the `with`-stack fully and I want to avoid duplicating the logic for
this between the two capturing types.

Change-Id: I6654f8739fc2e04ca046e6667d4a015f51724e99
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6485
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:16:46 +00:00
Vincent Ambo
6c9abc1f68 fix(tvix/eval): use correct lambda address in observer
Instead of the reference to the Rc, print the address of the Rc
itself.

Change-Id: I4560598924db7d2864d5c4ae9af847aee2ea7eff
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6471
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 12:16:46 +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
8643620eb1 fix(tvix/eval): always add history entries in REPL
... even if the code is broken.

Change-Id: I5898bceaebf201b97e8988c94c90e7fafff82529
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6462
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-10 21:57:13 +00:00
Vincent Ambo
4e06e5d2ba fix(tvix/eval): reintroduce 'InvalidAttribuetName' error variant
As pointed out by sterni in cl/6205, this is actually possible in
syntactically valid expressions like

  { ${12 + 13} = 12; }

Change-Id: Id8a1e3aceb551f288f9050c4eea563eb6572f1a7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6461
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-10 21:57:13 +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
83dd706a3a feat(tvix/eval): conditionally use tracing/disassembling observers
Gates the observes behind the envvars `TVIX_DUMP_BYTECODE` and
`TVIX_TRACE_RUNTIME`.

(hi grfn, yes, we should probably introduce CLI flags soon)

Change-Id: I4fa194a84b04593d609b96b44471c3644fb30296
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6459
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
2e018a50a7 feat(tvix/eval): implement OpTailCall
If the last operation within a chunk is a function call, the call can
be executed in the same call frame without increasing the depth of the
call stack.

To enable this, a new OpTailCall instruction (similar to OpCall) is
introduced, but not yet emitted by the compiler.

Change-Id: I9ffbd7da6d2d6a8ec7a724646435dc6ee89712f2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6457
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-10 21:57:13 +00:00
Vincent Ambo
6deaa0d6ce fix(tvix/eval): force value passed to builtins.toString
This introduces a macro to do the forcing, but this solution isn't
very nice and also does not work in all cases yet.

Change-Id: Icd18862ec47edb82c0efc3af5835a6cb6126f629
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6456
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-09 21:14:56 +00:00
Vincent Ambo
0aeca64777 chore(tvix/eval): clean up a stale comment
Change-Id: If1b02fe1c78398387ea98490e5b099f1ff1b4164
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6455
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-09 21:14:56 +00:00
Vincent Ambo
e2a942e4b2 chore(tvix/eval): clean up remains of previous disassembler impl
Change-Id: Ib402ea23a58dc52ed0c5a97178cb5d0e53d69300
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6454
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-09 21:14:56 +00:00
Vincent Ambo
e03a729fa3 feat(tvix/eval): implement TracingObserver for runtime tracing
This produces similar output to the previous tracing feature, but can
redirect the output somewhere else.

Change-Id: I9493c260f480904f3932cb74809b622c24d7be96
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6453
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-09 21:14:56 +00:00
Vincent Ambo
14ff889d60 feat(tvix/eval): implement runtime tracing methods for Observer
These methods make it possible to trace the runtime execution of the
VM through an observer.

Change-Id: I90e26853ba2fe44748613e7f761ed5c1c5fc9ff7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6452
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-09 21:10:10 +00:00
Vincent Ambo
cbf2d2d292 refactor(tvix/eval): move disassemble_op to the Chunk structure
Change-Id: Ic6710c609ed647bfa47d673aaf22c4da96c0f319
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6451
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-09 21:10:10 +00:00
Vincent Ambo
3cf5c40209 chore(tvix/eval): export some symbols from the crate
These are required for tvixbolt to work. This interface is definitely
not stable yet, though.

Change-Id: I4076498e8f42311de74ee4f33c93a3ee0c5f8d3a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6450
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-09 21:10:10 +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
7ae45342df feat(tvix/eval): implement (compilation) observer trait
This trait will enable library users of tvix-eval to observe internal
happenings of the compilation and runtime processes.

The initial methods of the observer will be called whenever the
compiler emits a chunk.

Change-Id: I668f6c2cfe3d6f4c1a1612c0f293831011768437
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6448
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-09 21:10:10 +00:00
Vincent Ambo
1fe6cfe5a2 refactor(tvix/eval): index into Chunk with ConstantIdx/CodeIdx
This is a step towards hiding the internal fields of thunk, and making
the interface of the type more predictable.

Part of the preparation for implementing observers.

Change-Id: I1a88a96419c72eb9e2332b56a2dd94afa47e6f88
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6447
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-09 21:10:10 +00:00
Vincent Ambo
8fdb67847c chore(tvix/eval): debug_assert that all jumps are patched
Suggestion from sterni in cl/6282

Change-Id: I1adbdda9ff74f55a2f72892ffa524808b305f403
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6445
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-09 10:48:10 +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
9f379ef6df fix(tvix/eval): hold thunk borrow as shortly as possible
At the point where control flow exits Thunk::force (which may be due
to recursing), it is vital that there is no longer a borrow to the
inner thunk representation, otherwise this can cause accidental
infinite recursion (which will be detected, but cause failures on
valid code).

Change-Id: I2846f3142830ae3110a4f5d2299e9d7928634504
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6436
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
d3421c1cb9 fix(tvix/eval): ensure disassembler prints continous lines correctly
There can be different spans on the same line, so the previous
implementation would duplicate line numbers unnecessarily.

Change-Id: I8d8db77177aee0d834a6ec3584641e1bd5f31c3e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6434
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
678533bfc4 test(tvix/eval): add test for stack slot accounting edge-case
This was fixed by some of the previous commits around scopes. It's
somewhat similar to a few other tests, but I had this one failing
earlier and everything else succeeding, so it is useful to keep it
around for sure.

Change-Id: Ie6cf372b5c805daf992cd87aeb3dfe91542c381c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6431
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
360c805efc chore(tvix/eval): remove accidentally duplicated test
This is the same as `eval-okay-attrs-simple-inherit`.

Change-Id: I23878accc6cd62c16ec96601239838a385d31306
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6428
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 19:54:02 +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
e9b6ecb0ee fix(tvix/eval): propagate scope depth when nesting scopes
Change-Id: Id441646db550f6195c2e247a0afbb5c9d91da8a0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6422
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 13:36:26 +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
a303ea3ff5 refactor(tvix/eval): implement much clearer disassembler output
With this change the runtime trace contains much more exact
information about the context of the computation (entering/exiting
calls etc.)

This is in large part due to moving the tracer to be a field on the VM
itself, which enables consistent ordering of traces across the
execution, and tracing an execution with its *input* instead
of *output* stack.

Change-Id: Ibe525e6e7d869756501e52bef1a441619ce7332c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6419
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 13:36:26 +00:00
Vincent Ambo
60ff8d046c chore(tvix/eval): print value when panicking on internals
This makes it much easier to figure out what happened while debugging
this sort of thing.

Change-Id: I2e0e8096709adc647d63c04f213c547c415e5f44
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6418
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 13:36:26 +00:00
Vincent Ambo
b83723a1ed fix(tvix/eval): force argument of builtins.length
Change-Id: Iaf94dfc7cb058f5c1c311066d92e01512e09cf71
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6417
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 12:53:20 +00:00
Vincent Ambo
0c0ae50f02 fix(tvix/eval): don't panic when printing a black hole
This could occur when the disassembler is enabled and tracing the
runtime while a thunk is being evaluated, as it would not be possible
for the *tracer* to borrow the thunk at this exact moment.

However, we know that if the borrowing fails here we are dealing with
a not-fully evaluated thunk (blackhole), which should just print the
internal representation.

Change-Id: I4bdb4f17818d55795368e3d28842048f488f0a91
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6416
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 12:53:20 +00:00
Vincent Ambo
2246a31e72 refactor(tvix/eval): return call frame result from VM::call
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 12:53:20 +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
6b3c3c9826 refactor(tvix/eval): add macros for generating Value casters
The casting methods of `Value` are pretty verbose, and actually
incorrect before this commit as they did not account for inner thunk
values.

To address this, we first attempt to make them correct by introducing
a standard macro to generate them and traverse the inner thunk(s) if
necessary.

This is likely to be a performance hit as it will now involve more
cloning of values. We can do multiple things to alleviate this, but
should do some measurements first.

Change-Id: If315d6e2afe7b69db727df535bc6cbfb89a691aa
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6412
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 08:45:15 +00:00
Vincent Ambo
0d7ad5e6d1 refactor(tvix/eval): pass a VM reference to builtins
This makes it possible for builtins to force values on their own,
without the VM having to apply a strictness mask to the arguments
first.

Change-Id: Ib49a94e56ca2a8d515c39647381ab55a727766e3
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6411
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 07:59:15 +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
Vincent Ambo
0a13d267f0 fix(tvix/eval): thread thunk forcing errors through correctly
With this, if an error occurs while forcing a thunk (which is very
likely) it is threaded through to the top by wrapping it in the
ErrorKind::ThunkForce variant.

We could use this to generate "stacktrace-like" error output if we
wanted, or simply jump through and discard everything except the
innermost error.

Change-Id: I3c1c8708c2f73ae062815adf490ce935b1979da8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6409
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 07:59:15 +00:00
Vincent Ambo
377ba19d75 feat(tvix/eval): ensure all errors always carry a span
Previously error spans were optional because the information about
code spans was not available at runtime. Now that this information has
been added, the error type will always carry a span.

This change is very invasive all throughout the codebase. This is due
to the fact that many functions that are called *by* the VM expected
to return `EvalResult`, but this no longer works as the span
information is not available to those functions - only to the VM
itself.

To work around this the majority of these functions have been changed
to return `Result<T, ErrorKind>` instead and an accompanying macro in
the VM constructs the "real" error.

Note that this implementatino currently has a bug where errors
occuring within thunks will yield the location at which the thunk was
forced, not the location at which the error occured within the code.
This will be fixed soon, but the commit is large enough as is.

Change-Id: Ib1ecb81a4d09d464a95ea7ea9e589f3bd08d5202
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6408
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
2022-09-08 07:59:15 +00:00
William Carroll
197fe37dae feat(tvix/eval): Support builtins.length
Get the length of a list

Change-Id: I41d91e96d833269541a1b3c23b7cc879f96d1e5a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6407
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-07 20:56:02 +00:00
William Carroll
15e2bc54f1 feat(tvix/eval): Support builtins.{mul,div}
Multiplication and division :)

Change-Id: I79e76f3b55b7e9b8d1eb09b3d9741140b4d75742
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6406
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-07 20:56:02 +00:00