I'm doing this because I figured it'd be an incremental improvement for
all the operator lookups that we do. Even to the extent that we've
discussed witness caching, I think it'll still apply. It does add one
more step to adding new interfaces (before, you'd just write the string,
now you add it to the def file and reference it).
I'll claim it makes GetClangOperatorKind a lot friendlier to read/edit,
nevermind removing the string comparisons. :)
This separates the return type from the return pattern, and replaces the
return pattern with a block of return patterns. This is a step toward
support for `ref` returns (where there's no corresponding return
pattern) and compund-form returns (where there may be multiple return
patterns).
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.
Give TupleLiteral and StructLiteral a constant value, if their contents
have constant values. Their constant values are TupleValue and
StructValue respectively. This supports their ability to convert to a
constant type (or facet type).
This way when deduce finds a TupleLiteral as the argument to a
_symbolic_ facet type, it can also find a constant value to use for that
argument. This allows deduction to move onto step two, where it can
substitute into the symbolic parameter from previous deduced arguments,
and then perform the conversion from the TupleValue to the desired facet
type.
Allow `PerformBuiltinConversion()` to convert from a canonical
TupleValue or StructValue to `type` instead of only from literals. Then,
also support conversion from a symbolic binding of type TupleType or
StructType to `type`.
If the value representation of `T` is a copy representation, but it
copies all of the bits of `T`'s object representation, then it's OK to
use that as the value representation of `MaybeUnformed(T)` too.
This fixes the behavior of interop with nullable pointers, which are
represented as an adapter of `MaybeUnformed(T*)`, and need to be passed
to and returned from functions on the Carbon / C++ boundary as `T*`s.
As a byproduct, the only test that exercised the "address of a temporary
object" diagnostic now trigers the "address of a non-reference
expression" diagnostic. We could restore it by using a type that doesn't
support `value_of_initializer`, but it seems better to remove the
diagnostic altogether: not only does it simplify the code, I'd also
argue "non-reference expression" is more accurate as a user-facing
description of the operand.
#6289 absentmindedly added fields in more places, and this is undoing
that plus further fixes.
This does some cleanup of types with relation to singletons. For
`TypeType` and `ErrorInst`, they're always complete due to a
`SetComplete` call in `file.cpp`. For `CppVoidType`, it's intended to be
incomplete by construction, and so a `TypeId` should be okay. The intent
though on not generally providing these had been that `GetSingletonType`
needs to be called to get a type to be marked as complete.
In the case of `AutoType`, removing `TypeId`does change a small printing
detail. I think that's old legacy that's just been carried forward.
Otherwise, for both `InstType` and `AutoType`, I've added
`GetSingletonType` calls where they were used in order to ensure
completeness is applied correctly. These calls cause small SemIR
permutations.
This causes `AutoType` to be seen by lowering, so I'm adding a
placeholder for it. Also merging two functions that look like they're
identical in intent -- not sure why they're separate.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
`const` doesn't mean much on the type of a value expression; it's valid
to remove it because we can't perform modifications to a const value
regardless.
We already allowed most of this, but only as part of adapter conversion
rather than in general, and we didn't previously allow it when the
source of the conversion was a reference expression.
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
The SymbolicBindingType refers to the type value that will be
substituted in for the BindSymbolicName, but holds onto the EntityNameId
from the BindSymbolicName instead of (or in addition to, for now) the
instruction.
The EntityNameId will be used to look in the ScopeStack to find the
witnesses either from the BindSymbolicName instruction, or other
instructions that specify `impls` constraints against the EntityName.
This will allow us to have the `T` in `I(T)` resolve to a `.Self`
reference in the type so that we get type equality with the binding's
type: `T:! I(.Self)`.
Previously it performed two kinds of operations, with a boolean
parameter to control whether it would unwrap FacetValue or not. This
made the function hard to explain as "canonicalization".
Now the contract of GetCanonicalFacetOrTypeValue is as follows:
1. For a facet value expression, it returns the canonical value of the
facet value.
2. For a `<facet value> as type` it returns the canonical value of the
`<facet value>`.
3. For other type expressions, it returns the canonical value of the
type.
1 and 2 together collapse together two representations of a facet value
(as a FacetType or as a TypeType) into a single canonical value, which
is important for constant comparison of facet values where the `as type`
is not meant to change the result. This is the case in impl lookups and
`.Self` comparisons.
The step of unwrapping `FacetValue` is only useful in the constant
evaluation of `LookupImplWitness` and is used to collapse *symbolic*
queries on `FacetValue(T)` and on `T` down to a single canonical value,
since they produce the same result later when `T` is replaced with a
facet value or type that can provide a concrete witness. This is now
extensively documented in the constant evaluation of
`LookupImplWitness`.
This change came out of a request/discussion in #6115 (see comment
https://github.com/carbon-language/carbon-lang/pull/6115#discussion_r2383696576).
When doing impl lookup with a constraint facet type including the
builtin `TypeCanAggregateDestroy`, we look at the type to see if it
satisfies it. However if the type is a facet value, we need to look at
the FacetType to see if the eventual concrete type is going to satisfy
it.
Note that we can do this check up front in the `LookupImplWitness()`
function without creating a symbolic instruction to be modified by
future specifics with a more precise type for the facet value, because
the result of `TypeCanAggregateDestroy` does not actually provide a
witness, so we don't need the final specific type.
This was noticed by removing the "shortcut" in convert for converting a
`FacetAccessType(<symbolic binding>)` to `typeof(<symbolic binding>)`.
By removing the shortcut, we go into impl lookup when checking `impl`
decls containing `TypeCanAggregateDestroy` via deduce.
This makes convert more consistent, it always makes a FacetAccessType
for a facet value, rather than only doing so after lookup returns. The
intention for this is that FacetAccessType will evaluate to
SymbolicBindingType in the future, so this will expose that constant
value to impl lookup instead of the original facet value, which will
avoid impl lookup having to deal with `.Self` or `BindSymbolicName`
specifically.
If a `BindSymbolicName` is converted to `type` and then to its exact
`FacetType`, we get a `FacetValue` wrapping the `BindSymbolicName` but
providing no different information: it has the same witnesses and
`FacetType` as the original `BindSymbolicName`. Yet it is a different
constant value, creating multiple canonical forms with the same meaning.
Now we make that `FacetValue` with the same `FacetType` as the
`BindSymbolicName` it wraps evaluate back to the `BindSymbolicName`,
making it the unique canonical form.
This makes the "shortcut" in convert for avoiding impl lookup when
converting from `FacetAccessType` to `FacetType` in this exact scenario
work the same as doing the full impl lookup.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Add `Dependent` value and initializing representations for types whose
representations are unknown because they are dependent. When generating
SemIR in such cases, use a worst-case initializing representation that
both provides a destination address and also propagates a potential
result value.
Use this to fix incorrect lowering and lowering crashes for specific
functions involving generic types that don't use a copy value
representation.
In lowering, be careful to distinguish between whether the initializing
representation for the generic return type uses a return slot (which
affects whether the SemIR declaration and call have one) and whether the
initializing representation for the specific return type uses a return
slot (which affects whether the LLVM IR declaration and call have one).
This is a bit of an experiment to see if there's a reasonable way to
write a shared enum type, rather than writing per-case wrappers for
things like `HasTypeQualifiers` or the printing. I think it's a bit
borderline complexity right now, but I'm not sure I can reduce it much
further.
This changes from things like `Internal::EnumClassName##RawEnum` to
`Internal::EnumClassName##Data::RawEnum` so that the enum entries can
have back references to bit shifts without needing to know the
containing type name. Because I'm trying to reduce duplication between
mask and non-mask enums, I did this to non-mask enums too.
This was motivated by #6035 adding another enum mask (which will grow
more entries, and is intended to switch if this is accepted), but I'm
not using that PR as a base here because I didn't want the merge
dependency.
Instead of hardcoding which types are copyable, add a `Core.Copy`
interface to perform copying. Move almost all the current copy support
to that interface. Some remaining pieces are still using builtin logic
after this PR:
* For tuples and structs, builtin logic is used to perform elementwise
copies. This also supports copying *adapters of* tuples and structs,
which seems like it may not be desirable, especially for non-extending
adapters. A `Copy` impl is provided for tuples of at most 2 elements, so
that `Core.Copy` constraints are satisfied, but we can't implement this
generally until we have variadics support, and don't yet have a
mechanism to generalize this to structs.
* For `enum` types imported from C++, builtin logic is used to perform a
copy. This is temporary until we have a mechanism to identify these
types from an impl in the prelude.
One lowering test in `toolchain/lower/testdata/class/generic.carbon` is
disabled for now, as it causes a crash in the lowering code due to an
ABI mismatch between the call signature in the lowered declaration of a
specific function and the call that is generated in the specific callee.
Fixing this is a little involved, and will be done in a separate PR.
---------
Co-authored-by: Geoff Romer <gromer@google.com>
Attach the cleanup to the `Temporary` instruction instead of to the
`TemporaryStorage` instruction. We create `TemporaryStorage`
instructions speculatively when creating an initializing expression, and
may overwrite those instructions with other instructions if it turns out
that a temporary is not required. Instead, wait until we finalize the
temporary and create a `Temporary` instruction to register the cleanup.
We already allowed this for reference expressions; this extends the
support to also cover value expressions. This requires a little more
work because the value representation of `T` and `MaybeUnformed(T)`
don't necessarily match in general.
* Treat `MaybeUnformed` and `partial` as qualifiers, like `const`.
* Allow pointer conversions to add qualifiers.
* Allow unsafe pointer conversions to remove qualifiers.
* Allow conversions on non-reference expressions to drop `const`.
* Allow unsafe conversions on any expression to drop `const`.
* Allow unsafe conversions on non-initializing expressions to drop
`partial`. For initializing expressions, we should initialize the
vptr when dropping `partial`; this is not yet supported so we reject.
* Allow conversions on reference expressions to add `MaybeUnformed`.
* Allow unsafe conversions on reference expressions to drop
`MaybeUnformed`. For non-reference expressions, additional work is
required, because the value / initializing representation may not
match between `T` and `MaybeUnformed(T)`, so those are rejected for
now.
Following the direction of #5913, add support for parsing an `unsafe as`
operator. For now, we allow one additional conversion using `unsafe as`
beyond the conversions supported by `as`: we permit pointer conversions
that remove qualifiers, such as `const T*` -> `T*`.
This is necessary if the source type is an adapter, as we would not
otherwise be able to determine what type it adapts and hence could be
converted to.
This addresses/avoids the duplicate import of vtables.
I went through a few iterations/etc along the way and left them in the
commit
history for the PR in case any of them are useful to illustrate how I
got here,
or worth revisiting.
Essentially I ended up with a circularity in importing - importing the
class
imported the vtable_decl which imported the virtual functions - and then
pending
specifics of the virtual functions needed the self specific of the
enclosing
class which wasn't ready yet.
Adding ImportRef to the vtable_decl to break the cycle caused me trouble
when
naming the vtable_decl instructions - so I tried making the functions in
the
vtable unloaded ImportRefs instead. That worked, but meant that
importing a
class still was doing O(number of vtable entries) even if the vtable
wasn't
used.
So I revisited the lazy vtable_decl - figured out how to make the naming
work
(when building the vtable_ptr, even though the vtable_decl doesn't have
to be
loaded for the vtable_ptr, I force it to be loaded anyway, to load the
vtable so
it's usable by lowering, etc). And then I could go back to the old
non-lazy
loaded vtable entries (using some loaded ImportRefs in the cases where
we needed
them/had already adopted them).
Then thinking about the VtablePtr instruction, went back/forth on
exactly what
it needed - went from VtablePtr's member being a VtableDecl InstId, to a
ClassId, then back to a VtableId as it was before this patch.
Naming the instructions has one oddity, that the VtableDecl and
VtablePtr
instructions seem to need to add the pending name for the VtableId -
despite not
using the VtableId in their own name - should the inst namer be doing
this work
for parameters of instructions rather than requiring the inst to do it
deliberately? (or am I holding it wrong in some way?)
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
* Rename the type.
* Change lowering to lower FloatLiteralType values as the placeholder
`{}` value we use for literals instead of as an LLVM f64.
* Change eval to convert the type as part of a floating point
conversion, so that lowering can lower converted constants properly.
For now we still represent a value of FloatLiteralType as a
double-precision APFloat. (That will need to change so that we can
losslessly convert literals to f80 / f128 values, and so that we can
convert literals to f32 values without double-rounding.)
When initializing a C++ thunk parameter:
* If we have an initializing expression, materialize a temporary and
pass its address.
* If we have a reference expression, pass its address directly.
* If we have a value expression with a pointer value representation,
pass the pointer.
* Otherwise, create a new temporary and initialize it with a copy of the
argument, and pass its address.
Add a new type, `custom_layout_type`, representing a struct type whose
size, alignment, and field offsets can be manually controlled. Use this
as the object representation type for imported C++ class types (which
also includes struct and union types), allowing us to model C++ class
type layouts. In passing, also add support for incomplete C++ class
types, mapping them into incomplete Carbon class types.
Map C++ fields into Carbon field declarations, allowing direct access to
C++ fields from Carbon. So far, no support is added for base classes nor
anonymous struct or union declarations; those will be added in
subsequent PRs. Also, we don't map C++ access control into Carbon yet,
so all C++ fields are accessible regardless of their access control.
For now we still use a `struct_type` as the object representation for
empty C++ classes, in order to continue to support our existing tests
that convert `{}` to empty C++ class types. This is temporary and should
be removed once we support interop with C++ class initialization.
Some specific features:
* Use `SpecificFunction` for vtable entries for generic classes.
* Create specific constants for vtable entries in classes derived from
generic classes to reference the appropriate specific of the function
in the context of such a derived class.
* Create specific constants for vtable_ptrs for uses of specific generic
classes.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Ensure `vtable_ptr`s(and the vtables they refer to) aren't
imported if the type is imported but the vtable isn't
needed (no initialization of a value of that type is required).
The goal was/is to reduce the overhead for vtables in generics - the
previous representation/prior to this patch caused a new vtable to be
created in every specific which isn't generally what we want for Carbon
generics (the whole specific/generic thing is meant to avoid creating
specific versions for things that can be a generic form parameterized by
a specific instead of manifest as a unique entity per specific)
So this moves vtables to a top level object (like functions, classes,
etc). Each dynamic class will have a vtable in this list.
Classes have a `vtable_ptr` instruction in them that points to the
vtable.
The actual generic support hasn't been implemented in this patch, as
I've been struggling with just getting this part of the migration going
& wanted to get it flushed out before adding the additional
complications.
It's possible more laziness when doing cross-file importing would be
suitable - for instance if we only need to reference the vtable from
another file, but don't need to know its individual contents, it may be
beneficial for the functions in the vtable to be import_refs (or to add
another layer of indirection - so it can be a single import_ref
all-or-nothing for the functions in the vtable).
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
When the binding pattern appears within a `var` pattern, convert to a
reference. Otherwise, convert to a value.
This gets the advent of code examples to produce the right answers again
:)
---------
Co-authored-by: Geoff Romer <gromer@google.com>
Undo changes that were meant to prevent use of a reference into
`ValueStore` after being invalidated. After #5576, the `ValueStore`
makes such references stable, so there's no need to worry about
invalidation.
No functionality change right now: we reject thunks where the signature
has no return type and the callee has a return type. But discarding the
expression is still the right thing to do.
With this enabled, entities that live in value stores are poisoned
whenever any action is taken that might invalidate pointers and
references to those options -- in particular, adding another item to
that value store, or attempting to load any entity from an import IR.
Subsequent uses of those pointers or references then trigger an ASan
failure.
This detects latent bugs where the pointer or reference to the entity
would become stale if we got unlucky about when the value store
reallocates, even in cases where the reallocation didn't actually
happen.
This is not enabled by default: it finds a lot of latent bugs, so our
tests don't pass with this option. This PR also includes fixes for a few
of those bugs.
---------
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
Remove calls to `InstStore::GetLocId()` to build a LocId from an InstId
now that they can be constructed directly from the InstId. Most uses of
LocId are just plumbing, so this does not affect them. However places
that want to look inside the LocId do not want to work with the InstId
form. In these places, introduce `InstStore::GetResolvedLocId()` which
converts a LocId (or an InstId as an optimization) into a LocId which is
not backed by an InstId. These locations can be printed (they have a
line and column when they are a NodeId), they can have flags added to
them (`ToImplicit`, `ToTokenOnly`), they can be converted to an
underlying ImportIRInstId, or they may be `None`.
`Dump()` is made to print a resolved location instead of printing the
InstId in the location, since (at least in my experience) the resolved
location is what is interesting in debugging, and this saves manual
`MakeInstId` steps in the debugger every time a location is of interest.
The LocId constructor from InstId is made `explicit` to add clarity to
function calls passing an `inst_id` now directly instead of calling
`context.insts().GetLocId(inst_id)`. To avoid needing to construct
`SemIR::LocId(...)` explicitly in all cases though, the diagnostics code
in Check uses `DiagnosticLocId` as its template parameter which accepts
InstId as well and does the construction of LocId from it.
Because LocId now requires an explicit construction from InstId, any
callers to `AddInst()` functions will have to explicitly convert to
LocId if they had an InstId, but not if they pass a NodeId. To make this
difference clear to callers, we `requires` that the input type can be
converted to LocId. This ensures that passing an InstId results in an
error at the callsite where the InstId is passed, instead of generating
a compiler error when trying to construct `LocIdAndInst` inside
`AddInst()`, which is less clear about what went wrong and doesn't seem
entirely intentional.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
We eliminate the `FacetAccessWitness` instruction, which would sometimes
immediately evaluate to a concrete `ImplWitness`, and sometimes remain
symbolic. This instruction is now replaced by `LookupImplWitness` in all
cases. To support the same use cases, when it is evaluated,
`LookupImplWitness` will look in the self value if it's a facet value,
and attempt to return a concrete `ImplWitness` from it before looking
for an `impl` statement.
The `LookupImplWitness` instruction's value is now canonical, even when
it evaluates to a symbolic `LookupImplWitness` instruction, by
canonicalizing the self value of the lookup query. This canonicalization
unwraps `FacetAccessType` and `FacetValue` instructions to get to an
underlying canonical facet value. However we must preserve and use the
non-canonical query while evaluating the instruction in order to look
for a concrete `ImplWitness` if the query self value was a concrete
`FacetValue`. The canonicalization ensures that symbolic witnesses
obtained from a facet value are compatible with those obtained from an
impl statement, as long as the self types originate from the same
canonical facet value though they may have been narrowed.
Member access now unconditionally does a `LookupImplWitness()`
operation, instead of only sometimes doing the lookup for a final impl
declaration.
`EvalImplLookupResult` is marked `[[nodiscard]]` so that we don't
construct it and forget to return it. This was a mistake made at one
point during the creation of this PR. And the `has_concrete_value()`
method no longer has a precondition that `has_value()` is true, since we
want to look for a concrete result only in the new use of
`EvalImplLookupResult` returned from lookup into the query self facet
value.
The TODO from `FacetAccessWitness` evaluation is addressed by ensuring
the index of the witness in the `FacetValue` comes from the required
interfaces of the `FacetValue`'s type, and that the type (a `FacetType`)
is the same facet type used in the query to construct the `FacetValue`'s
witness block. This is made possible by eliminating the
`FacetAccessWitness` indirection. The lookup into a `FacetValue` happens
while evaluating `LookupImplWitness` and it does so directly on the self
value. This gives a consistent view of the witness set and the facet
type, as they both come from the same instruction.
All of this with 400 less lines of code. :)
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
We already had conversion in place to implicitly convert these literals
to `type`. Now they can also convert to `FacetType`. This is done by
first doing a conversion to `type` and then converting that type value
to `FacetType`.
These constant instructions are all TypeInstId already in their type,
and this makes their names match.
Change the name of MakeSingletonInstId as well and update its comment.
We frequently want to operate on singletons. Per discussion, drop
`Singleton` to make the code shorter.
This started off as wanting to write `inst_id.is_error()`, but the
dependency relationship between ids.h and singleton_insts.h would
require some kind of delayed evaluation to allow the implementation to
remain in headers (which I suspect is helpful to have for inlining). I
could have added something like `IsErrorInst`, forward declared in ids.h
and defined in singleton_insts.h (which would always be included by
typed_insts.h), but the template approach felt like a decent balance
between (a) removing the boilerplate `::SingletonInstId`, (b)
understandability, (c) still visually mirroring if we immediately return
a singleton, and (d) flexibility for more than just `ErrorInst`. But TBH
I'd probably still have written `is_error()` if it didn't require
addressing the cross-header cycle.
Then I tried `SemIR::InstId::Is<SemIR::ErrorInst>`, which generally
worked with types but generated the complaint that it didn't shorten
*all* singleton uses. So pulling back on `::Is`, and instead just
dropping `Singleton`.
After #5280 there are a few more typed instructions that have an `InstId
type_inst_id` that always holds a type value. These are converted to
`TypeInstId` to encode this fact in the type system. The
`ConvertAggregateElement()` function in convert.cpp is now able to
receive `TypeInstId` for a couple arguments as well.
Additionally, the `type_inst_id` field of `StructTypeField` is made into
a `TypeInstId`.
The `TupleType::elements_id` is renamed to `TupleType::type_elements_id`
to try record the fact that it's an InstBlock of type value
instructions. We don't introduce a TypeInstBlockId at this time, but it
might be nice to make blocks of TypeInstIds in the future.
To assist in working with a block of InstId that are type values, two
additional helpers are added to the TypeStore:
- GetBlockAsTypeInstIds which turns an `ArrayRef<InstId>` into a range
of `TypeInstId`
- GetBlockAsTypeIds which turns an `ArrayRef<InstId>` into a range of
`TypeId`
We use these helpers in places that iterate over the
`TupleType::type_elements_id`.
Jon Ross-Perkins
Geoff Romer
Richard Smith
Dana Jansens
Boaz Brickner
David BlaikieandRichard Smith
Thomas Köppe