The purpose of the newline is to make it clearer where a given
diagnostic begins and ends, particularly as the first message of a
diagnostic may not be the error.
This is a trivial code change, but ripples edits through test files.
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.
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.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
On the parsing side, we treat `a.(b)` as a member access whose second
operand is a `ParenExpr` rather than a `MemberName`. A new node category
is added for the union of `MemberName` and `ParenExpr` to support this.
Checking is mostly reusing the same pieces we already have for simple
member access. Compound member access is in most ways a simplified form
of simple member access because it doesn't need to do any lookup.
Add a general substitution mechanism to support substituting symbolic
bindings with their values throughout symbolic constants and, more
specifically, types. This is done by decomposing the constant
instruction into its operands, substituting into the operands, and then
rebuilding the constant value by invoking the constant evaluator.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
When a member access names an interface member, perform impl lookup to
find the impl and its corresponding member.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
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>
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`.
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 enough to support calling methods that take a `Base` or `Base*`
as their `self`. But name lookup doesn't look in the base class yet, so
base class methods aren't actually found.
Implement toolchain support for `returned var` and `return var`.
- Modeled `returned` in the parse tree as a `ReturnedSpecifier`
appearing after the `VariableIntroducer`.
- Modeled `return var` in the parse tree as a `ReturnVarSpecifier`
appearing after the `ReturnStatementStart`.
- Factored out the implementation of `return` statement and `returned
var` handling in check into a new `return.{h,cpp}`. The parse nodes
themselves are still handled in `handle_*.cpp`. This allows easy code
reuse between `return` and `returned var`.
Instead of ad-hoc conversion tracking on some kinds of nodes that
conversion creates, consolidate tracking into a single node kind. This
frees up an operand on `Init` instructions that can be used to store the
destination.
Per the design, field access into a class value expression is a value
expression, even though we could produce an ephemeral reference
expression instead and avoid performing a value binding. This slightly
pessimizes class member access in some cases, but we should be able to
restore the old generated code by deferring actually performing the
value binding until a value expression is needed.
If the initializing representation is the same as the value
representation, don't materialize a temporary and perform a value
binding. Instead, directly extract the value, using a new
`value_of_initializer` node.
This removes a lot of redundant `alloca`s from our generated LLVM IR.
For now, we treat class types and `String` as non-copyable, because we
don't know how to emit SemIR to copy them yet. This will change as we
add support for copying those types when appropriate.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Adds a `BoundMethod` SemIR node to represent an `x.F` bound method, with
a new builtin type `BoundMethodType`. Reorganized conversion of call
expression arguments to also check and convert a `self` parameter in the
implicit parameters list.
In passing, improved diagnostics and error recovery for bad call
expressions. We now build a `call` node with the appropriate type and
value category, but with invalid arguments, if the argument conversion
failed, and diagnose calls to non-callable expressions.
`addr self` methods don't work properly yet; the `addr` is ignored for
now.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Add support for member access into classes, for both non-instance
members and for fields.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Track the fields in a class, and generate a corresponding struct type as
the object representation for the class. For now, we always use a
pointer as the value representation for a class.
Incomplete types may be nested within other types; for example, a tuple
type might have an incomplete type as an element. Handle such cases by
walking through nested incomplete types when completing a type. This is
done non-recursively in case a very complex type is formed.
Types are generally no longer completed at the point where they're
formed. Instead, we attempt to complete a type when it is used in a
context that requires a complete type, and diagnose if the type cannot
be completed at that point. This will be necessary for classes, which
can become complete after their first use, and helps tease out bugs
where a type completeness check is missing.
Using the computed value representation, fix lowering of struct and
tuple values to use the value representation rather than the object
representation. Fixes an issue found in the review of #3257.
This currently causes us to compute value representations of all types
as they are created, which generates substantially more SemIR to
represent types. We can get some of that back by deferring computation
of the value representation until the type is required to be complete,
but some of the additional cost here will persist with this approach.
I also considered making the computation of the value representation
type be something that lives entirely within the lowering phase, but I
think that's not the right approach in the longer term, because the
value representation will be semantically visible and relevant once we
start allowing it to be customized.
We should consider moving the nodes that exist to compute canonical
non-local types, including value representations, out into a separate
global block. That will clean up the SemIR representation substantially,
and make the SemIR produced for a function not depend on which types we
happen to have encountered beforehand. But that's not being done in this
PR.
---------
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
A `let` declaration is represented by a `bind_name` node in SemIR:
```carbon-semir
%b: i32 = bind_name "b", %a
```
Because `Check` encounters the pattern before it sees the value, we
first create the `bind_name` node with an unset value and don't add it
to the block. Then, once we've seen and converted the initializer, we
update the `bind_name` to have the value and add it to the current
block, after the initializer code.
Trust semantics to have put them in the right places.
Many parts of lowering still need to be updated to use the value
representation chosen at the semantics layer, but this is an incremental
step towards that.
Combine the initialization, implicit conversion, and value category
conversion functions into a single function.
This substantially reduces the duplication between these steps, and
ensures that we support the same set of conversions in all these
contexts. This also fixes some issues where we would not use the proper
value representation for tuples and structs after performing implicit
conversions.
This makes the difference between errors and lower-level diagnostics
visible to users, and aligns the toolchain's behavior with the
expectations in `driver_fuzzer.cpp`.
Fix a bug where we would perform the computation of the return location
in SemIR after we have already used it in some cases, leading to
assertion failures during lowering. Instead, accumulate a sequence of
instructions to compute the return location in a temporary block, and
overwrite the return slot with those instructions when we perform
initialization.
StubReference is replaced by a more general SpliceBlock node, that takes
a code block and a result value, executes the instructions in the block,
and produces the result. This is used in the uncommon case where more
than one instruction is required to compute the return slot, which can
happen if we need to first emit a temporary and then index into it, or
if we need to perform multiple levels of indexing before we reach an
entity to initialize.
This implements initializing expression semantics for structs and
tuples, following #2006 and discussions since.
Tuple and (and analogously, struct) literals are treated as having a
mixed expression category that is later resolved based on how the
literal is used, as either a tuple initializer or a tuple value, at
which point we create a `TupleInit` or `TupleValue` that represents the
formation of the tuple initializer or tuple value from the tuple
literal.
There's quite a lot of TODOs here, and the SemIR representation is still
not quite right, but this seems like a good place to checkpoint some
incremental progress.
Instead of modeling array initialization as a thin wrapper around tuple
initialization, handle it like a function call, with a return slot as
part of its input. This better matches how initialization via a call to
`ImplicitAs::Convert` will eventually work, and in particular lets us do
in-place initialization of arrays rather than always creating a
temporary.
IntegerLiterals are not signed, so get the zero-extended value rather
than the sign-extended value. Sometimes we use the high bit of the
`APInt`, though currently this only happens for the literals 8 and 9 due
to the way we convert decimal integers to binary.
Jon Ross-Perkins
Richard Smith
josh11b
Geoff Romer