Fix a collection of issues that were preventing lowering for overloaded
operators from working.
Instead of creating `import_ref` instructions during name lookup in the
current block, whatever that might be, we now create them in the `file`
block always. This avoids inserting them into blocks that might not be
intended to contain them, such as functions, and avoids the IR generated
for a function depending on which names we happen to have looked up
first.
When importing a class, function, or interface, import its enclosing
scope ID. This is necessary to allow us to distinguish between functions
at interface scope, which shouldn't be lowered, and other functions, and
will also be used in future to provide qualified names for declarations
when printing types. In order to support this:
- Track the constant values of namespaces created during importing so
that we can find them when resolving an import ref. Use those constant
values to convert an enclosing scope ID from the imported IR into a
corresponding ID in the current IR.
- Change how we do two-pass import of classes and namespaces so that we
can do two-pass import even for non-defining declarations, so that we
can import the enclosing scope.
While working on the final point above, I reworked `TryResolveInst` to
return a flag indicating whether another pass is necessary instead of
implicitly encoding this in the `ConstantId`. This permits the handling
of classes to be simplified; now `import_ir_constant_values` is only
accessed in a single place.
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Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Support is added for all overloaded operator interfaces in the current
design apart from `Assign`, which is going to require some more work to
properly handle, given that primitive assignment currently has a special
implementation for quite a few builtin types.
As we don't have support for generics yet -- in particular, generic
interfaces -- there is no support for `*With` interfaces, but homogenous
interfaces such as `Add` are supported instead.
Factor out building of call expressions so that overloaded operators can
generate calls.
Switch a few places from using specific kinds of NodeId to a general
NodeId. Because overloaded operators and other things like implicit
conversions can result in member access and function calls, those
operations can't require a specific kind of NodeId.
Add import support for associated entities, and fix import support for
interfaces and symbolic bindings. We now import interfaces in two steps,
first importing a forward declaration then a definition, just like we do
for classes. For symbolic bindings, we ensure that each BindSymbolicName
is imported only once, because its ID is used as its symbolic identity.
This is necessary because we (only) support operator interfaces that are
defined in an imported Carbon package for now.
The entire contents of `check/operator.cpp` should probably be
rethought. In particular, doing a lot of name lookups on each operator
is likely to be bad for performance. But this gets us to the point where
overloaded operators are basically working, which seems like a good
place to iterate from.
For now, the tests that the individual operators map to the right
interfaces are mostly generated by a script, but that's just because I'm
expecting a fair bit of churn in how we define the prelude and the
`impl`s -- in particular, when we add support for `AddWith`, we'll need
to update all the tests. The plan is to remove the script once things
settle down.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@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>
Interface support is pretty skeletal so this may need additions later,
but I think it's still worthwhile to fill in the necessary bits now.
With this change, the expectation is then that everything we have right
now which _can_ be imported, is supported for import (at least for the
"current package, no overlap" case).
By adding a constant to ClassDecl/InterfaceDecl, we're able to remove
name reference special-casing. Use TryEvalInst on the Decl to generate
the Type. For ClassDecl, then use the generated constant for
self_type_id.
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.
I'd excluded these initially just because I was thinking towards copies,
but under the current model I'm trying to catch all the decl types just
for consistency. Note references will still be a TODO error
(LazyImportRef is already tested for this, it just didn't feel necessary
to add individual tests while I try to sort out behavior).
Fixes an oversight where declarations in an entity's scope were being
added to the list of exports.
Note I'm trimming some Import API arguments as now-unused.
Richard SmithandJon Ross-Perkins
