Calls with template callee or args can now be deferred via an
InstAction. This allows code like this to check:
```carbon
import Cpp inline '''
template<typename T>
struct C {};
''';
fn F(generic T: type) {
let unused c: Cpp.C(T) = Cpp.C(T).C();
}
```
This allows generated functions to have different forms for different
parameters, and by-ref or by-value return forms. As a byproduct, this
allows generated functions to supply a return type _inst_ ID when they
have one, which preserves things like location information.
Example:
```carbon
import Cpp library "<vector>";
class C(T: type) {
var v: Cpp.std.vector(T);
}
inline Cpp '''
void F() {
Carbon::C<int> c;
c.v.push_back(123);
std::cout << c.v.back() << std::endl;
}
''';
```
A new `CallCppTemplateAction` is used to delay performing the C++
template call until non-symbolic arguments are known.
Treat `InstConstantKind::InstAction` the same as
`InstConstantKind::ConstInstAction`. Drop `ConstInstAction`, since the
two now behave the same.
Fix eval for specifics in a couple places to handle `InstId::None`.
When a template action is created, any (non-meta) instruction operand
will refer to instructions in the corresponding generic, or possibly to
a constant. This means that when the action is eventually executed when
forming a specific, it would see the generic value for that operand
rather than the intended specific value.
Fix this by refining `InstId` operands to refer to a corresponding value
in the specific, much like we would when rebuilding a constant in the
eval block.
Generalize ConvertToValue template action to handle other kinds of
conversion target that don't perform initialization. Initializing
conversions will need more work since they also need to use a splice to
form the storage block.
Building a `for` loop looks `Core.Iterate` up twice: once for
`NewCursor` to make the cursor, and again for `Next` to advance it. A
range that implements neither failed both lookups and reported both, so
a loop over something that isn't iterable produced two errors saying the
same thing about the same expression.
The second lookup is skipped when the first already failed, which is
what `BuildBinaryOperator`'s `diagnose` parameter is for. The
`ErrorInst` it returns instead does not reach the produced SemIR: the
loop is abandoned on the error either way.
Assisted-by: Claude Code
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Fix a bunch of cases where we use the same external name to mean
multiple different things in the same test. We've historically gotten
away with this, but under `--share-cpp-ast`, it becomes an error, at
least if the entity is either defined in, or used from, C++ code.
Assisted-by: Gemini via Antigravity (original change) and Claude Code
(suggested edits in review)
---------
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
This allows various templated constructs to get further through
checking, but typically we hit another unsupported action such as a
conversion or call, so it's not enough to make much work.
It's not enough for field types of Carbon classes to be complete in
SemIR. If the field is exported to Clang, we also need the type to be
complete in Clang's AST, since Clang assumes it has a definition
available for the types of all fields of a complete class.
For certain kinds of error, clang's parser will succeed but produce an
expression marked as "contains error". Clang's constant evaluator
asserts if given one of those, so return early if we encounter one.
Addresses part of issue raised in
https://github.com/carbon-language/carbon-lang/issues/7159 by
implementing float.add & float.sub builtin for FloatLiteralValues
The following code now compiles:
```
let a: f64 = 1.0 + 1.0;
```
Code handles case where operands are both decadic (base 10) and dyadic
(base 2) real literals, with the result being whichever format results
in smaller mantisssa.
File tests assert equality by converting to f128, this can possibly be
improved once CompareWith is implemented for FloatLiteral too.
Assisted-By: Gemini
This adds most support for default and final methods. Missing components
include rejecting definitions for non-default/final methods, and
permitting out-of-line definitions.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
We already test this in `access_modifiers.carbon`.
This also fixes a typo in the name of `access_modifiers.carbon` and
removes the `--dump-sem-ir-ranges` flag.
This is similar to the previously-added support for accessing generic
carbon classes from C++, but with the specific defined by Carbon, rather
than being derived from template args supplied by clang in
`LoadExternalSpecializations`.
Example:
```carbon
class C(T: type) {
var t: T;
}
alias A = C(i32);
inline Cpp '''
void F() {
Carbon::A a;
a.t = 123;
}
'''
```
Addresses part of issue raised in #7159 by implementing float.negate
builtin for FloatLiteralValues
The following code now compiles:
```
let a: f64 = -1.0;
```
To achieve this I switch the mantissa from being unsigned to signed.
Lexed literals within source file will still always be unsigned, however
it is now possible to create negative FloatLiteralValue constants. Main
non-local changes this causes is:
- All llvm::APInt parsing / printing calls flipped isSigned param
- Zero extension replaced with sign extension
- getActiveBits() replaced with getSignificantBits() for min bit width
calculation
The exported class was being inserted with a type inst ID as the key
(and looked up that way elsewhere), but when checking if the generic
class was already exported, the `first_decl_id` was being used. Make it
consistent, and opt for `first_decl_id` everywhere since it provides a
better location for diagnostics.
Implementing interface modifiers causes an infinite loop when generating
fingerprints because the witness value generates a fingerprint that's
dependent on something dependent on the witness value. We've debugged
this to the witness table's `elements_id` field.
This hack is a workaround for creating a new block type whose value is
not codependent with its identity.
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
This solves the problem where `interface` imports are incorrectly
diagnosed as duplicate names in impl files.
Follows the implementation logic used in `handle_class.cpp`.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
If we find an overload set containing mulitple methods, discard any
non-const methods and try again. This allows libc++'s `std::vector` to
be iterated with range-based for.
The toolchain crash is easily diagnosed, but looking at the log doesn't
offer immediate insight into why the program crashes. This provides us
with a graceful exit.
`String.size` is likely to be a signed word-sized integer in the future,
(per a Discord conversation). Changing to `i64` now allows us to iterate
over a string's contents using `IntRange`.
Add `Core.CppCompat.[U]Long64` to represent a 64-bit long that is not
`i64`. Treat it as being "just slightly smaller than" `i64`, like we
treat `Core.CppCompat.LongLong64` as being "just slightly larger than"
`i64`, so that we get implicit conversions `Cpp.long` -> `i64` ->
`Cpp.long_long` on all targets.
This follows the direction of proposal #5448, and seems like the obvious
extension of the `[U]Long32` and `[U]LongLong64` types added in #6275
for targets of this "shape".
Assisted-by: Gemini via Antigravity
Clang treats "file not found" as a fatal error and stops emitting more
diagnostics after reaching it, so these tests don't work in
`--share-cpp-ast` mode if they are all in the same file. So split them
into distinct test files.
Make multiple imports of the same header only parse it once per C++
domain. Reuse of the same header in `--share-cpp-ast` mode now reuses
the representation.
Importing a Carbon file with C++ dependencies now makes those transitive
C++ dependencies in the same C++ domain visible too.
Assisted-by: Gemini via Antigravity
Instead of creating a CodeGenerator per CppDomain, and then crashing in
lowering when we try to consume the same llvm Module multiple times,
create a CodeGenerator for each CppFile within the domain.
For now, we mulitplex all of Clang's ASTConsumer output to all code
generators, which means that any strong external definitions within a
Carbon file (for example, in an inline `Cpp` fragment) will be emitted
to all output files in the same `CppDomain`, resulting in link errors
due to symbol redefinitions. This will be addressed later. But this
should be sufficient for Carbon compilations in which such symbols are
not defined.
We also don't yet attempt to classify which compilations will need C++
code generation, and instead create a clang `CodeGenerator` for every
Carbon file that has C++ imports. For `carbom compile`, only one Carbon
file will need code generation, and yet we still build multiple
`CodeGenerator` objects in general. Fixing this requires more plumbing
from the driver, and this will also be handled in a follow-up.
Assisted-by: Gemini via Antigravity
This isolates the C++ imports in different Carbon files from each other
in `--share-cpp-ast` mode, so that a Carbon file can only see the
portions of the shared Clang `ASTContext` that it actually imported.
Assisted-by: Gemini via Antigravity
When implementing a named constraint, like `impl as N`, any accesses
through `Self` in the named constraint need to get the value of the
associated constant from the impl's witness table. This isn't possible
immediately, since the impl does not even exist until the declaration is
complete. We use the same model as for accesses found directly in the
impl declaration, but applied to the point where accesses in the named
constraint are substituted during identify to point at the impl's self
type. To get there, we need LookupImplWitness instructions in the named
constraint, when re-evaluated during construction of their enclosing
specific, to evaluate to ImplSelfWitness when they are a reference to
the type and interface being implemented.
Inject the name of a macro rather than its contents when computing its
expansion. If the macro refers to itself, it will not expand within its
own body, rather than expanding once.
Switching from `EnterTokenStream` to `EnterToken` exposed that our Clang
preprocessing environment was a little broken -- we reached the end of
the primary source file and starting tearing stuff down before we
actually finished parsing, which we were mostly getting away with before
but aren't any more. Enabled Clang's incremental processing mode to fix
this. This causes Clang to remain in the main source file when it
reaches EOF instead of popping it. This also causes the diagnostics for
invalid `module;` declarations to change, but in a way that seems not
really any worse than before.
Also slightly changes the diagnostics produced from macro expansion
failures. The new diagnostics are a bit more precise -- they now capture
the outermost level of macro expansion -- but we don't do a good job of
rendering the Clang snippet attached to the "in macro expansion" context
note yet, so the context looks a bit weird: we get two different
snippets attached to the same diagnostic.
In Convert, we require the source value's type to be compete so that we
can look for `base` classes and `adapt` relationships. However these can
only be present in a `ClassType`, so we only need `ClassType`s to be
complete.
Reduce the requirement in Convert to not complete types that are not a
`ClassType`, and which can not contain a `ClassType` as part of their
class.
Ideally we would only _only_ require the `ClassType` itself to be
complete, and only if we're looking for a base or adapt. However lower
depends on us completing all Convert source types that contain a class.
This seems to suggest we're lacking checks for complete types somewhere
else and Convert is making up for it. A TODO has been added. The
`toolchain/driver/testdata/compile/optimize/optimize_debug.carbon` test
is an example that CHECKs due to failing to verify the LLVM module if we
do not compute the complete type of all class-containing types in
Convert.
The critical step this PR is doing is to stop trying to complete a
`FacetType` when converting from a facet. This avoids trying to complete
a named constraint when converting `Self` inside that named constraint.
Doing so causes a cycle when the conversion of `Self` is performed in
eval of an `extend require` decl, since requiring the named constraint
to be complete re-evaluates the `extend require` decl again. A test is
added that crashed in an infinite loop before this change.
It also depends on #7584, which was intended to be an optimization but
is now load bearing. Because converting `Self` leaves an impl lookup
inst behind, and if that inst is re-evaluated inside impl lookup (by
forming a specific of a `require` decl through identify) then we have a
similar cycle.
During impl lookup, for each (generic) impl candidate, we form a
specific for that impl by deducing its generic arguments. Then we
compare the query interface against the impl's specific interface. That
comparison needs the deduced arguments applied to the impl's specific
interface. Previously we were doing this by getting the impl's
constraint facet type with the impl's specific applied (via
`GetConstantValueInSpecific()`) and then identifying that facet type
with the impl's deduced self.
Identify is a fairly expensive operation. It runs subst, trying to
replace `.Self` references. It walks named constraints. It collects
require declarations. We're looking at making it do _more_ in the future
too, including rewrite constraint resolution and collecting rewrite and
same-type constraints. For this reason we have a cache to make it cheap
on the second run, but it's still a very heavyweight operation to
involve in impl lookup, when all we want is to apply the impl's specific
to its target interface.
We almost have all the information we need to avoid the identification
step. We have the impl's specific after deduction. And we have the
SpecificInterface that the impl is targeting in the `Impl` struct. When
we form the specific for the impl itself, we resolve the declaration
block and form new constant values for all instructions in there, but
that does not cover the SpecificInterface that we're storing in the
`Impl` struct. So we add a new instruction to the impl's eval block,
which will be symbolic when the impl is generic and the target interface
depends on a generic parameter. And we store the `InstId` in the `Impl`
struct. This allows us to gets its constant value later with the impl's
specific applied. From that constant value we can then pull out the
SpecificInterface that the impl is targeting.
`abstract fn` was exported to C++ as a plain virtual function rather
than a pure virtual one, so the class wasn't abstract and could be
instantiated from C++.
Abstract functions no longer get a thunk since there is no definition to
call. The tests are prefixed with `fail_` since an abstract class still
errors on `Core.Destroy` regardless.
Exporting class fields in class specifics will require looking up
`ClangDecl`s by the field's `InstId` and the class's `SpecificId`. Add
the `specific_id` to ClangeDecl, and rework the reverse lookup to use a
`Set` with a `KeyContext` rather than a `Map`. The `Lookup` method now
takes an optional `SpecificId` argument, although currently it is always
`None`.
For `VarStorage`, reverse lookup is performed by the pattern `InstId`
rather than the `InstId` of the `VarStorage` itself, so also add
`pattern_inst_id` to `ClangDecl`, and provide a separate
`LookupByPatternInstId` method for reverse lookups. For this lookup, the
`inst_id` part of the key is set to `None`, so only the pattern's
`InstId` is used for lookup.
A method declared with `self` does not modify the object, but it was
exported to C++ as a non-const member function, so calling it on a const
reference would fail.
```carbon
class C {
fn Get(self);
}
inline Cpp '''
void F(const Carbon::C& c) {
c.Get();
}
''';
```
```
error: 'this' argument to member function 'Get' has type 'const Carbon::C', but function is not marked const
```
Import already maps `f() const` to `fn f(self)`, and this PR implements
the same behavior for exporting. No ref-qualifier is added, since that
maps to `ref self`, so that is unchanged.
`GetThisArg()` now builds `this` from the method instead of the parent
record, so that it picks up the method's const-qualifier.
Point symbolic witnesses into `.Self` written inside an impl decl at the
impl that is being declared. This is tricky because the impl does not
yet exist. So we use a new instruction `ImplSelfWitness` which _will_ be
replaced by the `ImplWitness` once it becomes available. The
`ImplSelfWitness` acts like a symbolic witness, except it does not
perform lookup, since we know which impl we will get a witness from.
This prevents us from finding other impls when performing lookups into
`.Self` in an impl decl, which produces incorrect/incoherent results.
Instead of building one Clang `ASTContext` per compilation, the
`--share-cpp-ast` flag causes us to build a single `ASTContext` and
share it across all contexts. One new abstraction is added: `CppDomain`
represents the Carbon-side view of a Clang AST that might be shared
across multiple `SemIR::File`s. This object owns the Clang instance and
the AST.
For now, we have no isolation between the C++ state exposed to different
Carbon compilations, and we have no multiplexing of generated LLVM IR
from C++ into different Carbon compilations, so the mode is not usable
yet. The plan is to keep it behind a flag until it's ready.
Assisted-by: Gemini via Antigravity
`DiagnoseOrphanImpl` used `definition_id`, but #7140 defines the anchor
as the first owning declaration, so a class declared but not defined was
rejected, which is why three cases in `orphan.carbon` were marked
`fail_todo`, and they now pass.
`fail_use_extern_class` no longer errors, `handle_class.cpp` never
passes the `extern library` name into the class entity, so `C` is
treated as locally owned and counts as an anchor. The expected error is
replaced with a TODO in the test, but it should come back once `extern
library` is implemented for classes.
Added method_alias.carbon test so that the class export code in
`ExportNameScopeToCpp` is tested. Refactored `ExportClassToCpp` so that
`ExportNameScopeToCpp` can reuse that code.
Moved the `identifier_info` code in `ExportNameScopeToCpp` into the
namespace block, because the name scope's name ID is not valid for
classes.
Added a call to `CompleteType` for classes exported via
`ExportNameScopeToCpp`, otherwise a "queried property of class with no
definition" assert is later reached (when adding methods) in the call
chain `BuildCppToCarbonThunkDecl` -> `DeclContext::addHiddenDecl` ->
`CXXRecordDecl::addedMember` -> `CXXRecordDecl::data`.
This is in addition to finding a `where` on the RHS of another `where`.
Since a generic binding introduces `.Self`, any `where` expression that
isn't part of a facet type modifying the binding itself would introduce
an ambiguous `.Self`.
Add virtual parse nodes for let, var, and form bindings, which goes
before the type. This allows us to track if `where` appears in the
binding's type. We only need to look for an invalid `where` if any
appeared in the type. We combine these three nodes together into a
single node kind, which requires us to remove the name from it as a
child. We move it up to the Pattern node again, and rename the
PatternStart nodes to PatternTypeStart as they are now located in the
middle of the Pattern nodes, just before the type.
And we only need to thaw `.Self` in generic bindings. Non-generic
bindings can only have `.Self` through a `where` expression, since the
name is not provided otherwise to non-generic bindings. And `where`
expressions thaw their `.Self` independently. So the binding only needs
to thaw a `.Self` that it introduced, which is only for generic
bindings.
We checked that requirements inside the impl-as target interface were
satisfied. But we also need to check that requirements coming from the
constraint facet type, or named constraints that it targets, are
satisfied.
The check for a specific in `TryMapClassType` is unnecessary;
immediately after it calls `ExportClassToCpp`, which has the same check.
The latter also has a `context.TODO`, which provides a clearer error.
Also improved the `LocId` in `ExportClassToCpp` to use the location of
the first decl rather than the empty location of the class type. This is
the same fix as
https://github.com/carbon-language/carbon-lang/pull/7533, just applied a
little more broadly. This makes the `context.TODO` above point at the
class rather than the start of the source file.
Nicholas Bishop
Özgür T. Önsoy
Geoff Romer
Richard Smith
DavidLoftus
Christopher Di BellaandRichard Smith
Dana Jansens
arhwx
