Identifying a facet type takes both a self and facet type as a pair, and
then encode the self into the IdentifiedFacetType. This makes a
constraint that requires some _other_ type implements an interface
visible in the IdentifiedFacetType. And it will help to enable facet
types with `where T impls Z` for `T` that is not `.Self` in the future.
IdentifiedFacetTypes are now stored in a CanonicalValueStore instead of
a RelationalValueStore as they key is the combination of self and
(declared) facet type together now.
When the self-type is a facet value (has type FacetType) this is most
straightforward. But when it's a type we need to construct a FacetValue
to construct a specific for a require decl, to replace the generic
binding of the symbolic `Self`, which has type FacetType. To do so, we
make a FacetValue with an empty FacetType (equivalent to TypeType). This
prevents any looking for witnesses through the FacetType, which matches
what you can get from a type directly, requiring witnesses to come from
finding an `impl` decl.
Add additional InstNamer logic for such empty facet types so they print
as `<typename>.type.facet` if possible instead of as just `facet_value`.
Adds Inst::IsOneOf which takes a variadic generic parameter pack of
kinds to check against. Also add forwarding functions to TypeStore and
InstStore. Convert uses of the regex `Is<.*\|\|` to IsOneOf.
This is based on #6522
The main changes here are:
- Introducing `InitForm` and `RefForm` to represent initializing and
reference forms (the two return forms currently supported by the
parser).
- Introducing the `FormType` singleton inst to represent their type
(i.e. `Core.Form`).
- Emitting an inst representing a function's declared return form as
part of handling the function signature.
The return form inst is currently ignored. Subsequent PRs will expose it
in `SemIR::Function` and use it to determine the form of call
expressions.
Pursuant to recent decisions on #6124, switch `Destroy` to use a
`CustomWitness` for its implementation. Right now this is manufacturing
no-op implementation functions on each lookup, which obviously isn't
ideal but is intended as a first pass. I'm mostly trying to find the
right balance between updating the approach to reflect new decisions,
while still breaking apart work in a way.
The `CoreInterface` logic is intended to build on `CoreIdentifier`
support. We have a number of additional interfaces that require
specialized logic, and that'll extend pretty far with C++ interop, so it
seemed easiest to have a generic function for it. That's what's
replacing the logic inside C++ interop that was doing string comparisons
(which could have already been moved to `CoreIdentifier`, I just missed
it in my first pass).
This adds `CustomWitness` support because the `Destroy` witnesses can be
imported cross-file. `CustomWitness` was previously only used for C++
types, which don't yet support import, which is why that wasn't
previously an issue. The addition of `query_specific_interface_id` is
similarly needed in order to get correct sorting of witness blocks when
imported.
This PR also removes builtin constraint logic (note this is in a
separate commit to help review; it's not a separate PR because it's
difficult to split apart without tests breaking). This had been made
generic with the expectation that destroy, copy, move, and conversions
would all need related support. Under the new decision, we are not going
to do blanket impls and will instead just manufacture a `CustomWitness`
for everything.
A lot of SemIR fingerprints change, but that's probably because the
addition of `Destroy` on core classes is yielding structural changes.
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).
The FacetTypeId should never be used directly, since the RequireImpls is
a generic and the facet type may be parameterized by generic bindings.
So instead, it should be accessed through GetConstantValueInSpecific,
which works with the facet type InstId that is also already present on
RequireImpls. This change to use GetConstantValueInSpecific was done in
#6435, so the FacetTypeId is now unused except in formatting. So we can
remove it.
This depends on #6435.
When forming an IdentifiedFacetType, we collect interfaces named by
require decls in named constraints that the facet type refers to. These
interfaces come with a specific, but the require decl is inside an named
constraint which may be generic. So we need the specific being applied
to the containing named constraint to also be applied to the require
decl and its target interfaces.
This uncovered that the facet type in require decls was not being
imported correctly, as it was not being attached to the require decl's
generic. This is fixed by making import of RequireImplsDecl multiphase,
so that the decl instruction exists before we resolve the facet type
within it. And by pointing the generic importing machinery to the
RequireImplsDecl, and from there to the RequireImpls structure to get
the generic id.
Then `ImplStore::GetOrAddLookupBucket` can use an IdentifiedFacetType to
correctly get the interface being impl'd, both in the local and the
imported named constraint case. Which allows us to correctly diagnose
redeclarations in the impl file of an impl of an interface through a
named constraint. And to correctly _not_ diagnose them when the specific
in the generic named constraint differs from other decls.
Right now, the impl lookup can both fail to resolve the specific
definition because it's symbolic, and return a "final" constant because
it's a `final impl`. This is adding an instruction to help ensure the
specific is resolved.
The constant evaluation is fully recursive, but I'm not adding a TODO
since that's a known issue with impl lookup in general.
I was trying to figure out the right way to get specifics to be added to
the work.
Technically, we could keep the pending_specific list; this is taking a
different approach of inserting inside the work stack, which will do
extra work moving entries, although typically that should be expected to
be small. One challenge of `pending_specifics` is that if we would need
to shift them to work after both `Done` (for immediate processing) and
`Retry` (for processing after the current instruction is later revisited
and done). That feels kind of awkward as additional tracking to do.
Also, the common case is probably that there's either 0 or 1 specifics
being added, so an additional vector may be significant overhead. That's
why I leaned more in this direction of just inserting them in the vector
of work.
About the same # of LOC, but maybe less work to analyze correctness?
Versus the template, could also stamp that out in the helper function
and still avoid the duplication of calls before/after HasNewWork.
Similar to how I've left `rewrite_constraints`.
Alternately I'm also kind of tempted to rename GetLocalSpecificInterface
and GetLocalSpecificNamedConstraint to instead be overloaded functions
(or to provide overloaded versions), which would allow this to drop the
function type parameters. But, naming is hard.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
This continues work to eliminate pending generics/specifics and get them
to be interleaved with instruction imports. I'm trying to use
`FinishGenericOrDone` here as a way to help ensure that code correctly
handles generics, where the simple alternative would be for each
`TryResolveTypedInst` call `SetGenericData` directly (but which might
make it easier to call the wrong `ResolveResult` function, and we do
need the `GenericId`s to be passed).
This is just an incremental step towards removing pending logic. The
rest seems like it'll be more complex due to interdependencies (I've
been poking at behavior).
This is part of trying to rewrite pending specific/generic code to make
use of the standard constant resolution flow. The LoadImportRef code was
a particular sticking point due to the recursion it does, which makes it
difficult to adapt over.
We add tests showing that `ImplStore::GetOrAddLookupBucket` is doing the
wrong thing for impls of a named constraint, as the impl-file
redeclarations of impls in the api file are not getting flagged as such.
To do the right thing requires us to be able to get the constraint from
a require declaration with the specific of the named
constraint/interface applied, which is future work as described in the
[open discussion
notes](https://docs.google.com/document/d/1Yt-i5AmF76LSvD4TrWRIAE_92kii6j5yFiW-S7ahzlg/edit?tab=t.1ji9ixn9bbnn#heading=h.kijomnov90rz).
Every test that used `addr` before #6283 should be using `ref` after
this PR. In most cases that was done in #6283, but this PR transitions a
few that I missed in that first pass. In addition, #6283 cloned the old
`addr` tests from `foo.carbon` to `foo_addr.carbon` in order to maintain
test coverage during the transition; this PR removes those cloned tests.
There are two uses I'm not converting here, that seem to want the
"shortest" behavior. For everything else, I'm going to `zip_equal` since
it's more restrictive.
I wish `zip` were named `zip_shortest`.
Proposal #5168 defines when a facet type must be identified or complete,
and what it means for an interface and a named constraint to be
identified or complete. This updates the toolchain to match the
requirements.
This implements identification of a facet type to require completed
named constraints and to include any interfaces from named constraints
into the resulting IdentifiedFacetType.
To complete a facet type, each interface in the IdentifiedFacetType, and
any interface named though a require declaration from them, must be
complete.
When importing an Interface or NamedConstraint, walk the block of
`RequireImplsId`s, and for each one:
- Import the RequireImplsDecl from it, which also imports the
`RequireImpls` structure and its id.
- Collect those decls and build a block of `RequireImplsId`s for the
local SemIR to reference from the Interface or NamedConstraint.
The import of RequireImplsDecl is done in a single phase instead of
three, unlike other decls. This is possible since require declarations
have no name, so they can't be referenced by instructions inside them,
thus there's no cycles to concern ourselves with.
- Makes a little more use of `MakeImportedLocIdAndInst` instead of
`UncheckedLoc`
- Requires use of `MakeImportedLocIdAndInst` with `ImportIRInstId`;
previously optional
- Relevant `if constexpr` moves to `AddPlaceholderImportedInst`, but is
more narrowly scoped there.
- Refactors out `AddPlaceholderImportedInstInNoBlock` to reduce how many
spots do an explicit `imports().push_back(...)`
I'd also considered removing `MakeImportedLocIdAndInst` where possible,
but went this route so that changes to the expected parse node wouldn't
affect callers. When it's required, `MakeImportedLocIdAndInst` is always
there; when it's conditionally present, changing `Parse::NodeId` between
enforceable and not-enforceable would require refactoring any callsites
that assumed one or the other.
Right now some of the `ResolveResult` factories are on it, ones that
involve `ImportRefResolver` aren't; this more consistently makes callers
use `ResolveResult::` when returning a result.
I was looking at this due to the addition of more
`GetAsTypeInstId(AddLoadedImportRef(` in #6344. Looking at
`AddLoadedImportRef`, it also felt like the first declaration would be
clearer if collapsed into its overload (the overload is the only
caller). Note one benefit of using `ImportContext` in
`AddLoadedImportRef` is being able to call
`local_constant_values_for_import_insts` to handle the `GetRawIndex`
code.
This has subtle effects on the number of imported instructions, but
seems more standard for how this code is being written...
`GetLocalConstantId` calls `GetLocalConstantValueOrPush` which does
`local_constant_values_for_import_insts().GetAttached`. So what this is
really doing is causing some intermediate import steps to be skipped.
But per test changes, that doesn't really affect SemIR and will probably
have negligible effect. This *seems* right to me, otherwise I'd expect
we should probably refactor all `GetLocalConstantId(InstId)` calls.
They are not used for impl lookup or verifying anything yet, but now
they appear in the textual semir.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
This imports the entire `NamedConstraint` structure when importing
`NamedConstraintDecl`. This will be required to identify a facet type
that contains a named constraint, as we will need to pull the `require`
decls out of the `NamedConstraint` structure to do so.
I tried making the `InterfaceDecl` code path
[templated](https://github.com/carbon-language/carbon-lang/pull/6308#discussion_r2482655927)
to reuse it, but it was a lot of template parameters including field
pointers into `InterfaceDecl`, `GenericInterfaceType`,
`SpecificInterface`, and it was very hard to read so I gave up on that
approach here.
This resolves a TODO in `expr_info.cpp` by using the inst kind rather
than the bound value to track the binding's category.
Since we're churning all the `bind_name` insts in testdata anyway, I'm
also taking this opportunity to align the inst naming with the design's
terminology, by calling these insts "bindings" (this aspect of the PR is
dependent on #6231 resolving an ambiguity in that terminology). For
consistency we'll need to rename several other insts as well (see the
TODO on `RefBinding`); I'm deferring that to a separate PR to minimize
the review load, but I think those name changes are in-scope for this
review.
Rather than assume reallocations can occur, we've switched to providing
stable references, so simplify related code.
Only removing the comment in `BuildGeneric`, no refactoring, because I
don't feel a refactoring would be a significant improvement.
When deducing arguments for generic parameters of an `impl`, the
deduction calls `Convert` on the input arguments. Often, the input
argument is a facet, and needs to be converted to a type via
FacetAccessType in order to produce a different facet. These
instructions end up being added to the semir, but only their constant
values are needed for the resulting specific returned from Deduce.
In the best case, these extra instructions are just noise in the semir,
or they just cause instruction names to get differentiated with larger
suffixes.
In the worst case, these extra instructions contain references to
instructions from a generic context, and leak them out of that generic
context and into another. In particular, when importing a
LookupImplWitness instruction, the re-evaluation of it can do deduce
(when the lookup is against a generic `impl`). The instructions created
in Deduce are not part of the import, and end up referring to imported
instructions from the local context, which leads to confusion in the
toolchain, and can crash.
The `import_self_specific.carbon` test demonstrates this. It causes the
`I.F` function to be imported from the `I` interface when building the
witness table for the `impl`. Doing so imports the specific of `C` which
includes a LookupImplWitness for `Self.Accoc` in `I`. The `Self` is a
BindSymbolicName with generic binding index 0, in `I`. When Convert
creates instructions in the generic `impl forall D`, however, they end
up referencing and including this BindSymbolicName into its eval block.
But the generic binding 0 in the `impl` is a very different thing (a
value of type `E`). This confusion leads to crashes.
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)`.
This fixes and tests two crashes related to what I was observing [on
#toolchain](https://discord.com/channels/655572317891461132/655578254970716160/1422723976483831848).
The approach to Cpp imports taken in #6086 is problematic because it
returns before the work stack is completed, and doesn't store the
resulting constants. This fixes the approach taken in that PR.
Use the `CheckIRId` as a unique identifier for the scope of an `InstId`
- if an `InstId` is created within the scope of one `CheckIRId` it must
not be used in the scope of a different `CheckIRId`.
This is achieved without extra storage, but with false negatives for
large inputs.
When an `InstId` is created, the original index of the `Inst` is XORed
with a tag derived from the `CheckIRId` to produce the final `InstId`.
When the `InstId` is used, the expected tag is XORed with the `InstId`
to get back to the original index - if the tags don't match, the
resulting index will be corrupted, likely too large - resulting in an
out of bounds index CHECK-failure.
(the tag value is derived as such:
* take the CheckIRId
* left shift one bit (padding zero)
* left shift another bit (padding 1 - used to signify that the resulting
`InstId` has a tag combined into it)
* reverse the bits
In this way, the tag is unlikely to overlap with the index for small
test cases - making it possible to separate out the `CheckIRId` from the
index in these cases to provide more meaningful debugging/CHECK
messages, and more informative `SemIR` textual dumping that can now
include the `CheckIRId` along with the `Inst`'s index in the name of an
`inst`)
The test churn here is improved printing as tagged `InstId`s can now,
with best effort (more likely for small test cases where the `CheckIRId`
and the `Inst` index aren't at risk of overlapping from the high and low
bits), render the `CheckIRId` as part of the inst's name. Going from
`instNN` to `irMM.instNN`.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
This is in support of a goal of changing the blanket `destroy` impl to
use (roughly):
```
private fn CanAggregateDestroy() -> type = "type.can_aggregate_destroy";
// Handles aggregate type destruction.
impl forall [AggregateDestroyT:! CanAggregateDestroy()] AggregateDestroyT as Destroy {
fn Op[addr self: Self*]() = "type.aggregate_destroy";
}
```
That isn't done here because there's still other issues that migrating
raises. What this *does* do is add the builtin functions, and in
particular, support to `FacetTypeInfo` to make `CanAggregateDestroy`
work.
The "special requirement" approach in `FacetTypeInfo` allows us to
support restricting a blanket impl under the current approach of impls.
Maybe we'll find a cleaner approach that can work in the future, but
this fits into the current model by propagating similar to other
requirements. I'm using an enum mask because we have a number of similar
things to add (e.g. copy, move) but I'm not sure we need a full vector.
A few alternatives considered were:
- Supporting syntax more like `where .Self impls
TypeCanAggregateDestroy(.Self, SupportedInterface,
UnsupportedInterface)`. I think it'd be a little cleaner, but requires
better compile-time evaluation in order to assess the type of the call.
Right now it's expected to be a `FacetType` too early to make this work,
and I was concerned about pouring too much more time down this route.
- Providing an actual interface, in particular doing name lookup back
into `Core.` for an interface. This would've added name lookup overhead,
and the question of whether an `impl` exists.
- Generating an interface. This avoids the name lookup, but would still
raise the question of whether an `impl` should also be generated. Work
I've previously done generating interfaces for class destruction also
feels complex to both write and understand (an unfortunate issue).
- Still modeling as an `ImplsConstraint`, for example by defining a
special `InterfaceId::CanAggregateDestroy = -2` similar to what we do on
other ids. I was hesitant because of how this expands the number of
modes of `InterfaceId`, and things for consuming code to watch out for,
for what feels like a relatively niche set of use-cases that are only
interface-like.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
As proposed in [Carbon: C++ interop for overloaded functions and
function
templates](https://docs.google.com/document/d/1KUxumZtNe3mY3TsjW2s_ZADOlAaFlrtsLKHVILtqIaM/edit?tab=t.0),
Clang is used to perform the overload resolution using C++ rules, when
an overloaded C++ set is called from Carbon. Once a function is
selected, it's converted into a Carbon function and called using the
Carbon rules including argument conversions.
A single non-templated function is treated the same way as an overload
set and the same rules apply for its call.
Template functions are not supported yet.
Demo:
a) Non-templated function calls:
```c++
// --- overloads.h
auto foo(int a, short b) -> void;
auto foo(double a) -> void;
auto foo(int a) -> void;
```
```c++
// overloads.cpp
#include "overloads.h"
#include <cstdio>
auto foo(int a, short b) -> void {
printf("hello from foo_int_short(%d, %d) \n", a, b);
}
auto foo(double a) -> void { printf("hello from foo_double(%f) \n", a); }
auto foo(int a) -> void { printf("hello from foo_int(%d) \n", a); }
```
```c++
library "Main";
import Cpp library "overloads.h";
fn Run() -> i32 {
Cpp.foo(1.1 as f64);
return 0;
}
```
```
$ clang -c overloads.cpp
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link overloads.o main.o --output=demo
$ ./demo
hello from foo_double(1.100000)
```
b) Constructors:
```c++
// --- constructor_overloads.h
class C {
public:
C();
C(int a, int b);
};
```
```c++
// constructor_overloads.cpp
#include "constructor_overloads.h"
#include <cstdio>
C::C() { printf("hello from C() \n"); }
C::C(int a, int b) { printf("hello from C(%d, %d) \n", a, b); }
```
```c++
library "Main";
import Cpp library "constructor_overloads.h";
fn Run() -> i32 {
let c1: Cpp.C = Cpp.C.C();
let c2: Cpp.C = Cpp.C.C(1, 2);
return 0;
}
```
```
$ clang -c constructor_overloads.cpp
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link constructor_overloads.o main.o \--output=demo
$ ./demo
hello from C()
hello from C(1, 2)
```
Follow-ups:
- `Cpp.foo({})` - proper handling of struct literals as call args.
- Fix access for overloaded sets.
- Fix tests:
- Method calls: `error: missing object argument in method call
[MissingObjectInMethodCall]` in tests.
- Fix `toolchain/check/testdata/interop/cpp/import.carbon` test.
- Fix `enums` support.
- Fix `str` -> `std::string_view` mapping.
Part of #5915
This avoids impl lookups involving, say, `Core.Int` pulling in all ~65
impls in "prelude/types/int", which resulted in a lot of unnecessary
importing work, followed by a lot of unnecessary inst namer and inst
formatter work.
Before:
```
Ran 1335 tests in 6186 ms wall time, 146818 ms across threads
Slowest tests:
- toolchain/check/testdata/interop/cpp/function/arithmetic_types_bridged.carbon: 5611 ms, 5532 ms in Run
- toolchain/check/testdata/interop/cpp/function/operators.carbon: 2034 ms, 1981 ms in Run
- toolchain/check/testdata/primitives/import_symbolic.carbon: 1796 ms, 1786 ms in Run
- toolchain/lower/testdata/operators/arithmetic.carbon: 1729 ms, 1728 ms in Run
- toolchain/lower/testdata/function/generic/call_recursive_sccs_deep.carbon: 1700 ms, 1697 ms in Run
[==========] 1335 tests from 1 test suite ran. (682 ms total)
```
After:
```
Ran 1335 tests in 2419 ms wall time, 109587 ms across threads
Slowest tests:
- toolchain/check/testdata/interop/cpp/function/arithmetic_types_bridged.carbon: 1748 ms, 1665 ms in Run
- toolchain/check/testdata/interop/cpp/function/operators.carbon: 1106 ms, 1057 ms in Run
- toolchain/lower/testdata/function/generic/call_recursive_diamond.carbon: 1044 ms, 1041 ms in Run
- toolchain/lower/testdata/function/generic/call_recursive_sccs_deep.carbon: 1015 ms, 1012 ms in Run
- toolchain/lower/testdata/operators/arithmetic.carbon: 998 ms, 997 ms in Run
[==========] 1335 tests from 1 test suite ran. (652 ms total)
```
That's still slower than it should be, but a large improvement
nonetheless.
Fixes#6029
Dana Jansens
Geoff Romer
Jon Ross-Perkins
David Blaikieandjosh11b
Ivana Ivanovska
Boaz Brickner