This was to track use of a declaration after import, prior to a
redeclaration. Per [discussion on
Discord](https://discord.com/channels/655572317891461132/1217182321933815820/1236016521059237962),
we likely don't need this check due to the change in behavior of
`extern`.
Rather than potentially getting one of many `extern` decls and depending
on it by accident, it is now planned to be _required_ to be imported,
and the library doing a non-`extern` decl must _know_ it's importing the
`extern` decl. The stricter requirement on the library means it now
seems more reasonable to use the `extern` decl.
So kind of rolling back #3831, though keeping `ImportIRInstId` (at least
for now) and keeping `Loaded`/`Unloaded` terminology (seems a nicer
fit).
First steps towards using constant values in lowering.
For now, we reuse the regular instruction lowering to lower constants.
This mostly works, because we don't actually need an `llvm::Function` or
a current basic block when lowering a constant most of the time.
However, a special case is needed for lowering aggregate value constants
because they would otherwise create a stack alloca to store the
constant. Separate constant lowering code will be added in a future
change to clean this up.
When lowering a constant initializing expression, the result is a value
of the destination type, rather than code to initialize the destination,
so a separate copy step is required when finishing initialization from a
constant for a type that uses in-place initialization. Handling this
required extending `ReturnExpr` to track its destination location.
We currently often create non-constant `*_access` SemIR instructions
that are only used by constant `*_init` instructions. These cause
lowering to leave behind `getelementptr` instructions in the lowered IR
that are now unused. It should be possible to detect this case and avoid
producing these instructions, or to produce them lazily, but for now
we're just leaving them around for LLVM to clean up.
Use a level comparison during substitution to determine whether we're
substituting a particular binding. Evaluate symbolic bindings with the
same name and the same level to the same symbolic constant, for example
across redeclarations of a generic function.
Adds support for unary `-` and binary `+`, `-`, `*`, `/` for floating
point types.
Real literals are now transformed to `llvm::APFloat`s during the check
phase into the `FloatLiteral` instruction.
This PR likely collides a bit with #3892 and might need to be updated
when that one is merged.
Factor out `SemIR::InstNamer` and also use it when lowering to LLVM IR.
Automatically name all instructions created with our `IRBuilder` based
on the name computed by the `InstNamer`, and likewise name basic blocks
using the label generated by the `InstNamer`.
Move some of the existing naming logic out from lower into `InstNamer`
so that it's also used in SemIR. In particular, we now name call
instructions after their callee, or after the builtin name for calls to
builtins.
Computing and adding these names isn't completely free. This instruction
naming is designed to be optional, so that we can turn it off for builds
where the LLVM IR will only be converted to assembly and won't be seen
by a human, but so far it's enabled unconditionally. We can tune that
later as needed.
Move completeness check to the point where the function is defined or
first called. This means we also defer deciding whether the function has
a return slot until that point. Instead of storing a return slot per
function, store the location of the return storage, which may or may not
be used, and compute and store a separate flag saying whether to use it
at the point of first use or definition.
This is the final piece in supporting simple `Make` functions in classes
as a replacement for constructors.
`i32` is retained as a special case for now, for bootstrapping purposes,
and maps to `BuiltinIntType`, which is distinct from `Core.Int(32)`.
This will be removed later once we support `Core.BigInt`.
For now this provides both the `iN` types and also the builtins to
support `Core.Int(N)`. The intent is that we'll change the `iN` support
to rewrite to calls here when we do that for the other type literals and
type keywords.
No conversions between integer types are supported yet, and all literals
are of type `i32`, so we can't actually form values of any of these new
types.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
This doesn't significantly change logic, although I'm trying to add the
location to used state.
The issue I'm trying to address is how to identify a declaration as
"allowed to be redeclared". Consider:
```
library "a" api;
extern fn F();
```
```
library "b" api;
extern fn F();
```
```
library "c" api;
import library "a";
import library "b";
var x: auto = F();
fn F();
```
What currently happens is:
1. On import of "a", `F` becomes ImportRefUnused
2. On import of "b", `F` becomes ImportRefUsed in order to merge.
3. In "c", the call `F()` doesn't change the state.
4. In "c", the declaration `fn F();` needs some breadcrumb to understand
whether "F" has been referenced, as in step (3) here.
What I want to happen is:
1. On import of "a", `F` becomes ImportRefUnloaded
2. On import of "b", `F` becomes ImportRefLoaded in order to merge.
3. In "c", the call `F()` causes `F` to become ImportRefUsed
4. In "c", the declaration `fn F();` detects that `F` is already
ImportRefUsed, and can use the associated `used_id` for a diagnostic
about why redeclaring is invalid.
Note this PR isn't implementing (4). I'm focused on the refactoring to
add a new ImportRef state here.
Note we only identify conflicts between libraries in the current package
during import.
This restructures the BUILD because of dependency cycles between cpp
files... We're going to need context's name lookup to handle things such
as merging, merging requires function logic, function logic requires
context access. Per discussion, going with a single large cc_library for
now rather than trying to split out small libraries.
I'm envisioning the new merge.* as a hub for cross-declaration merge
logic. Note function.cpp is already pretty sizable, and I think it may
lean a little function-specific even if there are some utilities that
could be split out.
The purpose of this change is to allow something such as a FunctionDecl
instruction to note an imported instruction as the "loc_id". Note that
doesn't occur here: this change is already very sweeping in edits. There
is no testdata affected, intended to show equivalent behavior.
We might want to consolidate NodeId references towards LocationId, but
if that's preferred, I'd still like to split it out. A lot of this just
piping through LocationId where it's a build error otherwise, enough
that imports should be able to start using it for diagnostics.
ValueStores are added but still unused -- just flushing out structure
for review.
Restructuring SemIRLocation is necessary to use LocationId this way. For
TokenOnly, it's not getting used in Parse, so I migrated it to Check and
it's now specific to SemIRLocation.
I also considered making LocationId reference an InstId (which would
need to be an ImportRef) instead of an ImportIRInstId. However, that
would've required import.cpp to add instructions for decls which are
reached during resolution -- we typically don't have an inst ready for
use. An extra inst is essentially 16 bytes in InstId's ValueStore + 4
bytes in LocationId's ValueStore, whereas this is 8 bytes per.
In preparation for adding more builtins, factor out the handling of
builtin function kinds into separate files.
Add checking for builtin function signatures. The mechanism used here is
intended to provide a lot of flexibility for declaring generic builtin
functions and pretty arbitrary constraints on the types of parameters of
builtin functions. For now, these constraints are checked when the
builtin function is declared. The hope is that this will suffice, but if
not, it should be straightforward to switch to doing some of the
checking on call and share logic between the checks.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
For now, a builtin function is defined by specifying a string literal
initializer in a function declaration:
```carbon
fn MyBuiltin(a: i32) -> i32 = "builtin.name";
```
End-to-end support is included for a sample `"int.add"` builtin
performing integer addition, covering constant evaluation and code
generation.
The implementation here needs substantial refactoring before we'll be
ready to start adding more builtins. That refactoring work will be
coming next. This change is aiming to checkpoint some incremental
progress.
This revamps the support for cross-package imports, making them look
more like a namespace. The planned model is mentioned on
[#toolchain](https://discord.com/channels/655572317891461132/655578254970716160/1217586076022210670).
This does not implement name lookup into the new namespace structure.
A few key changes in this PR (it's a little sprawling) are:
- Moves logic for adding package imports from context.* to import.*
- Remove SemIR::Import, which was the prior model. This is instead now a
SemIR::Namespace with the NameScope getting a new import_ir_scopes
field.
- Allow SemIR::Namespace to use Parse::ImportDirectiveId in addition to
the prior Parse::NamespaceId
- The import_ir_scopes field includes a NameScopeId so that as we
traverse to child namespaces, we can directly perform name lookup in the
other IR.
- is_closed_import now tracks whether a namespace comes from a different
package. This has a diagnostic implemented in decl_name_stack.
This was previously discussed at
https://discord.com/channels/655572317891461132/655578254970716160/1209975051588210729.
I'm initiating this mainly because we typically use "id" suffixes to
indicate an `IdBase` being passed around and the non-id suffix of
`parse_node` suggests at it carrying more data than it actually does.
There used to be more reason for avoiding `node_id` because
`SemIR::InstId` used to be named `NodeId`, but that's no longer
necessary. As a consequence, I'd like to rename `parse_node` to more
precisely reflect its type.
In full, this is doing:
```
parse_node_kind -> node_kind
parse_node -> node_id
ParseNodeCategory -> NodeCategory
ParseNodeKind -> NodeKind
ParseNode -> NodeId
```
This is primarily in check and sem_ir, but with some `parse_node_kind`
references in parse too.
Pluralization is consistent with name forms on both sides, so that
wasn't part of my replacements.
Add an instruction to hold the witness table, along with a corresponding
type to keep things simpler. Add `check/impl.{h,cpp}` to house the new
logic. No checking of impls against interfaces is performed yet.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
`Self` is modeled as a `bind_symbolic_name` with no corresponding value,
for now at least. In the future it might make sense to model it as a new
kind of instruction, or as a `bind_symbolic_name` whose value is a
`param`, but for now we just want it to introduce a symbolic constant.
In order to convert a value like the `Self` of an interface to a type, a
new instruction `facet_type_access` is introduced. This notionally
accesses the "type" field within a facet, converting it from a pair of
(type, witness) into just the type.
Previously we used the default inst block formatting, which writes out a
parenthesized list of references, which would always be 'unexpected
instref's because nothing else prints the instructions in the decl
block.
In addition, track the decl block for function declarations like we do
for other kinds of declaration. This means that the parameter
declarations for a function are now properly rendered into the formatted
IR. Note that this adds a lot of verbosity to `function_decl`, but it
does accurately reflect the IR, and we'll probably want this information
to be printed once we start supporting more complex generic function
declarations.
This removes almost all the 'unexpected instref's in our formatted
output. There are remaining cases when a declarative scope contains
multiple blocks, where we only track one of those blocks. That happens
when there is control flow within declarative scopes, and for error
recovery when a class or interface or similar is defined more than once.
As requested in #3730.
When declaring an associated entity in an interface -- just associated
functions for now -- create an associated entity value and corresponding
type to represent a "slot in a witness table". Also track the list of
associated entities on the interface so that we will eventually be able
to check impls against them.
Associated entities are represented as the integer index of their slot
in a witness table.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
I believe this PR is sufficient to pull in all current class features,
including the current bits of inheritance which have been implemented.
Because a class declaration can reference its own type, this creates an
incomplete type prior to constant loading.
Right now, the object representation is imported proactively, but
individual fields are left as ImportRefUnused. This means that member
functions and similar will only be imported if called.
This also adjusts how function parameters are being handled, to match
the expectations of Self param structure.
When formatting, I'm starting to look into constants. Otherwise we get
"unexpected instref".
Overall, there are a few things that may be worth further discussion:
- The lack of a constant corresponding to the ClassType on ClassDecl is
inconvenient -- I'd like to see how zygoloid feels about trying to
restructure this. i.e., I'm setting a constant in order to be able to
track things down later, it'd be nice if the normal IR did this simply
for consistency, or if we were able to combine these rather than having
separate instructions.
- Should we shift the parse node tracking further, and go with a setup
wherein imports can embed import references into that? e.g., negative
values go to another array which includes a ImportIRId for printing
diagnostics, replacing the invalid NodeId.
- Can the formatter switch to a more general scan of instructions for
naming, to eliminate the ImportRef constant approach added here?
- GetExprValueForLookupResult special-casing instructions felt
surprising, I might see if there's a way to restructure to avoid that.
But I think these issues are things that can be separated out.
Adds `BindAlias` with a hybrid of `BindName` and `NameRef` semantics. I
think it's slightly closer to `BindName` because it introduces a name,
so I'm going more in that direction. This also matches the need for
`bind_name_id` with imports on enclosing scopes.
Note, only things that look like a name reference are being allowed on
the RHS of `alias`. This includes builtins that look like name
references, such as `bool`, but not ones that turn into values
underneath, such as `false`.
Collect the contents of an `impl` into a scope, and start doing very
basic checking for `impl` declarations and definitions.
This change adds two new `Id` types to the set of type that `NodeStack`
supports -- `ImplId` and `NameScopeId`.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
- Rename `ScopeIndex` to `ScopeId`, because the order is not meaningful.
This avoids collisions with `SemIR::ScopeIndex`.
- Change `GetScopeFor` to use an `if constexpr` chain rather than
duplicating the numbering logic across multiple functions.
- Simplify `GetNameFor`, avoiding multiple identical overloads.
As requested in review of #3683.
Right now, ConstantValueStore defaults to having unknown values use
NotConstant. This generally works for the current IR, but with imports
we're expecting sparse entries which are generally unknown -- and
distinguishing between NotConstant and simply unset would be helpful. As
a consequence, add Invalid.
We discussed whether to simply have ConstantValueStore default to
Invalid going forward, or to make the default flexible. The upside to
the former is consistency, the upside to the latter is that it should
result in fewer Sets when operating on the current IR (which will more
frequently have known non-constant values). This PR offers both
approaches in separate commits, but I somewhat lean towards the latter
for fewer array resizes.
Note, a totally different approach would be to use a different class
(not ConstantValueStore) for imported IRs -- then the default of Invalid
versus NotConstant would be type-dependent. However, I expect we're
going to want to do at least somewhat consistent lookups, and using the
same ConstantValueStore for both cases allows avoiding a virtual
interface or templating. Also, I'm hoping to only maintain the
ConstantValueStore for an imported IR as part of Context (not File),
which would mean the SmallVector storage overhead is ephemeral,
mitigating one of the potential advantages of using a different type for
imported IRs.
I'm basically just nudging down the path I think is right here. Adding a
small bit more support, but also more tests to capture cases that I
think will need to be verified as working.
With diagnostics like "Value of type `<function>` is not callable.",
that's because it expects a FunctionDecl but is instead finding a
ImportRefUsed. I'll need to work out the necessary support for a
callable function.
One more (hopefully last) rename on the Import instruction renaming.
I was kind of tempted to rename to just "IRId", since the IRs aren't all
imports. However, this felt easier to read, and a better choice than
CrossRef because it's more consistent with the other ways imports exist
in code. (even if IRs aren't all imports, most use-cases are derived
from imports)
Note though that import_irs may include IRs not just from direct
imports. Beyond the builtin IR, I'm thinking that for indirect imports,
or the prelude, we may end up adding them. e.g., so that constants can
be generated for indirect imports and still correspond to a directly
known IR, and for a given IR that's indirectly imported multiple times
to be deduplicated locally. I'm not there yet, I'm just mentioning this
to help give background for naming thoughts.
This is a bit of a cleanup; I probably should've just renamed CrossRef
instead of adding ImportRefUsed.
Adding `is_builtin` to InstId is more about providing a standard API for
the check, which I expect to add a little more of.
Shifts import tests to validate that the BuildValueRepr CHECK isn't
accidentally hit.
Recent runs of `clang-tidy` for me started showing more errors, and this
is a collection of changes to address them.
First, I've systematically applied the disabling tag to all C++ rules
under //explorer/... with `buildozer` so we don't spend time analyzing
this code or reporting errors from it. Not sure this was strictly
necessary, but it seemed like a nice consistency improvement.
Next, I disabled a buggy check for missing `default` cases in
`switch`es. It seems to get confused by the fancy conversions in our
`enum_base.h`. We don't miss much with this as the Clang compiler
warnings for `switch` catch most of our actual bugs. I also removed the
local disabling of this now that it is turned off centrally.
Lastly, I added error checking to two file descriptor manipulating calls
in the `file_test` infrastructure.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Builds on #3656.
Under the prior "lazy" model, we had been planning to copy instructions.
Under the current "unused+used" model, we're restricting that to
constants. I'm trimming back some of the ResolveIfImportRefUnused logic
because it was more appropriate for the former model.
Right now, I'm adding ImportRefUsed direct creation in import.cpp for
namespaces. I think I'll need to do something similar in
RseolveIfImportRefUnused... I'm still trying to think about how to
manage type information there (which needs to come in as an import
reference itself, and probably have some amount of deduplication before
forming a TypeId). So ImportRefUnused lacks a type because I'm hesitant
to aggressively load it, whereas ImportRefUsed should *always* have a
type but it's just an error while I think things through.
For reference, ImportRefUnused and ImportRefUsed are mainly split in
order to track the boolean "used" without making fundamental
modifications to Inst for bit packing (this effectively instead packs a
bit into InstKind). AnyImportRef currently excludes the type because
it's mainly for diagnostic printing at the moment. It could end up with
a TypeId that would end up Invalid for ImportRefUnused, though it could
also be that the TypeId is only accessed when using ImportRefUsed
explicitly.
This makes some changes to the formatter so that ImportRefUnused and
ImportRefUsed will both be labeled as "import_ref" with an "unused ->
used" argument change in textual IR, but is otherwise not changing
logic.
Building on #3636 which handles the general import case, add special
casing for namespaces. Namespaces can be combined cross-IR, so it's a
little more complex.
The implementation adds import_id to the Namespace instruction as a
reference to find the original using the normal structure. This is
achieved by moving the name_id to NameScope to free up space.
---
I considered a few alternatives...
I considered adding import_id to NameScope, but:
1. It's more consistent with things such as Function or Class that
provide name_id on the info object rather than the instruction.
2. I thought it more likely that there would be more NameScope cases
that might want a name_id rather than the import_id, since ImportRef
will typically be used.
I considered putting the import source (cross-ref IR id + inst id) on
the NameScope versus a separate ImportRef, which seems like the
strongest argument towards the NameScope approach because it removes an
instruction. That just felt inconsistent though, and the overhead of
instruction-per-imported-namespace should be low (theoretically few
namespaces should be used). Plus I feel a bit odd adding two
generally-unused ids to NameScope.
A specialized Namespace structure could also have been created to store
the import_id, but that would add an indirection to the NameScope.
Rather than producing multiple constants with the same value, fold all
instances of a given constant to the same constant instruction.
A future PR will use this to replace the current type canonicalization
system.
The parse nodes are still tracked as part of the same value store
interface in order to ensure parity, but they're split out from Inst
itself in order to reduce the size of Inst -- the expectation is that
they don't need to be passed around quite as much.
This change doesn't actually reduce the passing very much, although
there are hints of it: AddInstAndPush doesn't typically need a separate
parse node from the one on the Inst itself, for example. In a couple
spots I changed code to rely a little more on the InstId until the
ParseNode is needed, but it's very low hanging fruit where done. I think
convert could do more to not eagerly fetch the parse node before its
use, but more cleanup felt it would be easier to handle separately. I'm
currently viewing this as making such cleanup _possible_ rather than
executing on it up-front.
But also, I want to make sure there's a consensus to head in this
direction before pulling the trigger. We speculated that this would
result in the parse node being passed around less, and I do think that's
the case, although it's a bit fuzzy in the change.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
This is accomplished by tracking an extra bit on the ID we store in the
constant values table, and propagating that from subexpressions to the
enclosing expression. This extra bit is not yet computed correctly for
types; that will be addressed in later PRs.
---------
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Form a side table with constant values for each instruction. Evaluation
is only supported for a few very simple kinds of instruction for now.
This is not observable outside of the SemIR output, because nothing
depends on expressions having a constant value phase yet.
This change adds a `BindSymbolicName` instruction for generic bindings,
paralleling the existing `BindName`. A mechanism is also added to allow
both kinds of binding to be accessed uniformly, for convenience in the
case where the two different kinds of binding are treated the same.
Generic bindings of type `type` are allowed to be used as types,
although no operations are provided for such types. For now lowering
treats these types as empty structs, which seems like a reasonable
lowering for non-monomorphized unconstrained types.
This is a step towards adding enclosing scopes for imports. It creates
an indirection for all bind names.
We discussed specializing for bindings that are in function scope (i.e.,
not a useful enclosing scope for imports or diagnostics). However, the
thought is to go ahead with this singular approach for now, and only
change structure if it's a performance issues so that we have
incrementally fewer instructions to handle.
Jon Ross-Perkins
Richard Smith
Pablo Paglilla
