Start treating function calls as initializing expressions instead of as
value expressions.
This required adding support for expression categories. Value bindings
and temporary materialization conversions are created where necessary to
transition between expression categories. For a function call with a
return slot, we speculatively create a materialized temporary before the
call and either commit to it or replace it with something else later,
once we see how the function call expression is actually used.
This change follows the direction suggested in #3133 for initializing
expressions: depending on the return type of a function, the return
value will either be initialized in-place or returned directly. This is
visible in the semantics IR, which is a little unfortunate but is
probably necessary as this is part of the semantics of the program.
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Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Splits IR files into SemIR, and logic files into Check. These will be
split into separate directories as part of a later move; the namespaces
are being done first in order to vet the switch, and hopefully make
conflicts a little easier to manage due to the substantial renames.
A lot of this is just automated removal of Semantics prefixes from
names, adding namespace references where needed. A few special-cases
are:
- SemanticsIR -> SemIR::File
- A few things were discussed, like Unit, CompileUnit, or CompiledUnit.
Unit was too vague for chandlerc, and I thought CompileUnit might lead
to incorrect inferences (CompilationUnit would be more precise, but
typically written as SemIR::CompilationUnit which is pretty long). File
seemed to be a short name that we could agree on.
- SemanticsIRFormatter -> SemIR::Formatter
- FormatSemanticsIR -> SemIR::FormatFile
- SemanticsFileTest -> CheckFileTest
- It remains in the Testing namespace, where just "FileTest" might be
too broad a name.
- SemanticsDeclarationNameStack::Context ->
Check::DeclarationNameStack::NameContext
- This avoids a Check::Context name shadowing.
Changes check_internal.h to include ostream.h to improve finding of
Print/operator<< (otherwise it didn't compile).
This is part of #3070
Refactor type canonicalization so that we can reuse the same code for
building a `T*` expression and for forming the type of an `&x`
expression.
Add basic computation of expression category in order to check that we
only take the address of durable reference expressions. This is
currently computed on demand rather than being tracked as part of the
semantics node, but in most cases can be determined by looking at only a
single expression, so caching it in the node doesn't seem worthwhile
yet. This decision should be revisited if we start doing more complex
category calculations.
Also add trivial lowering support, but it doesn't work properly yet
because lowering doesn't yet take the expression category into account.
Semantic handling for use of `T*` and `const T` as types.
There's no way to form values of these types yet, and no conversions for
them are supported.
Factor out the common code to canonicalize types using a folding set,
and switch to using the same folding set for all kinds of type by adding
the kind as part of the folding set key.
Improve type printing to not include the `as type` portion when the type
is printed in a context within another type where a conversion to `type`
is implied, as in `{}*` and pre-existing cases like `({}, {}) as type`
(which we used to print as `({} as type, {} as type}) as type`.
This adds a distinction between Unused and SoloParseNode, rather than
equating the two. This is intended to help identify nodes which are
getting pushed but maybe don't need to be.
Not totally done because I want to adjust declaration name handling due
to a quirk with how it mixes Name with Expression, but almost done. Once
that's done the type punning will be completely gone.
Richard SmithandChandler Carruth
Jon Ross-Perkins
Farzana Ahmed SiddiqueandFarzana Ahmed Siddique