The primary change in this PR is to split the `Initializing` expression
category into separate `ReprInitializing` and `InPlaceInitializing`
categories, depending on whether initialization uses the types
initializing representation, or is guaranteed to be in place. It also
rationalizes and documents the SemIR-level semantics of those categories
(including where #5545's "ephemeral entire reference" category will
fit), and introduces two new inst kinds to close gaps exposed in the
process.
Some additional secondary changes:
- Consistently format the storage arguments of initializers with `to`,
regardless of whether initialization is in-place, and document the `to`
notation.
- Rename some inst kinds and functions, and restructure some of the
code, for clarity and consistency with the new documentation.
- Resolve a TODO to handle more category conversions in
`CategoryConverter`, in order to make it easier to reason about category
conversions.
See #6588 and the review history of this PR for background.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
The key changes are:
- Function output parameters are now prefixed with `out`, and more
consistently formatted as named parameters.
- Function and inst output arguments are now written as part of the inst
form, rather than as one of the inst arguments.
As a drive-by fix, this also changes `Temporary::storage_id` from
`DestInstId` to `InstId`, because it doesn't represent an output
parameter of the `Temporary` inst itself.
See the review of
[#6532](https://github.com/carbon-language/carbon-lang/pull/6532) and
[this Discord
discussion](https://discord.com/channels/655572317891461132/999638000126394370/1458268977020141589)
for additional background.
Avoid using a large switch that needs to be manually extended when
adding a new kind of instruction. Instead, the expression category for
an instruction is now specified when defining the `InstKind`.
In passing, add a distinct expression category value for patterns. This
isn't used for much except some error checking at the moment, but it
keeps the number of instructions that we need to manually classify as
`NotExpr` despite having a type very low.
Previously we walked the global variables defined by the current file
and emitted an LLVM global variable definition for each of them. Now
instead, when emitting a constant reference to a global variable, we
emit an LLVM global variable declaration, and we then subsequently walk
the global variables defined by the current file and convert each of
them from a declaration to a definition.
In order to make import of names of global variables work, add support
for import of `var`, as well as support for importing `tuple_access` and
`tuple_pattern` in the case where the `var` has a tuple pattern in its
declaration. Also treat `bind_name`s that are reference bindings to
`var`s as having the same constant reference value as their `var` so
that we can properly import and lower them.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
Fixes#5186
With @zygoloid's kind assistance, this generalizes the existing
non-const lowering of ClassInit, that had previously only handled
InitializeFrom, to find other cases - such as a nested ClassInit used to
initialize a class member.
This refactors the `FindReturnSlotArgForInitializer` from
`check/convert.cpp` into `sem_ir/file.{h,cpp}` for use from lowering
(since lower doesn't depend on check, which I assume is an intentional
layering constraint - so figured it made sense to move it to sem_ir, and
found one or two similar-ish utility functions in `sem_ir/file.{h,cpp}`,
so figured that was a good spot)
Geoff RomerandRichard Smith
David Blaikie