Commit Graph
29 Commits
Author SHA1 Message Date
Boaz Brickner b88b53e7e3 C++ interop: Add support for importing globals (#6005)
This supports importing globals in the global scope and within
namespaces, and support for class static data members.

C++ Interop Demo:

```c++
// my_global.h

extern int my_global;
void inc_my_global();
```

```c++
// my_global.cpp

#include "my_global.h"

int my_global = 5;

void inc_my_global() {
  ++my_global;
}
```

```carbon
// main.carbon

library "Main";

import Core library "io";
import Cpp library "my_global.h";

fn Run() -> i32 {
  Core.Print(Cpp.my_global);
  Cpp.inc_my_global();
  Core.Print(Cpp.my_global);
  return 0;
}
```

```shell
$ clang -c my_global.cpp
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link my_global.o main.o --output=demo
$ ./demo
5
6
```

Part of #6006.
2025-09-08 08:34:55 +00:00
Richard Smith db0a00d713 Fix double-destruction of temporaries. (#6010)
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.
2025-09-04 19:19:59 +00:00
Richard Smith cb5e2e1597 Improve support for qualification conversions. (#5999)
* 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.
2025-09-03 21:00:12 +00:00
Richard SmithandDana Jansens 4483d1e5a7 Recover better from invalid C++ classes. (#5992)
When importing a class definition, don't ask for the class layout if the
definition is invalid. Avoids an assertion failure in Clang.

---------

Co-authored-by: Dana Jansens <danakj@orodu.net>
2025-09-02 19:32:35 +00:00
Boaz Brickner 8adb3570ac C++ Interop: Add support for char (#5988)
Added tests for different character types.
`char` is currently not in primitives prelude, so had to use full
prelude.

C++ Interop Demo:

```carbon
// main.carbon

library "Main";

import Cpp inline '''
auto output_char(char c) -> void {
  printf("%c", c);
}
''';

fn Run() -> i32 {
  let msg: array(Core.Char, 13) =
      ('H', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd', '!', '\n');
  for (c: Core.Char in msg) {
    Cpp.output_char(c);
  }
  return 0;
}
```

```shell
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link main.o --output=demo
$ ./demo
Hello world!
```

Part of https://github.com/carbon-language/carbon-lang/issues/5263.
2025-08-29 01:11:24 +00:00
Richard Smith 82ba1a43a1 Support for importing C++ enum types. (#5978)
We import C++ enum types as Carbon class types as adapters for the
corresponding builtin integer type, and we import enumerator constants
as integer constants of that class type.

No operators are supported on such values for now; eventually once we
start asking Clang to implement operators on C++-owned types, these
types should be handled in the same way. However, they can be converted
to the corresponding integer type with `as` via adapter conversion, and
integer builtin functions can operate on them.
2025-08-26 23:11:35 +00:00
Richard Smith 3533668186 Support for building thunks for C++ constructors. (#5977) 2025-08-26 21:49:11 +00:00
Richard Smith 8c9080801c Support for building thunks for C++ methods. (#5972)
Also tweak how we import C++ methods to properly handle C++23's explicit
object parameters.
2025-08-25 22:33:51 +00:00
Richard Smith b72c11e94a Support importing nested types from C++. (#5955)
Fix the algorithm for importing declarations in dependency order to
properly walk the dependency graph. Add the parent declaration of a
declaration to the dependency set so that we have a parent declaration
context to import a declaration into.

Fixes a crash when attempting to import a class whose parent is not
imported.
2025-08-20 07:39:12 +00:00
Richard SmithandJon Ross-Perkins b2b0b4a73f Improve recovery from bad type imports. (#5953)
The main change here is that a bad type appearing somewhere within a
field or base class of a class shouldn't cause an import of that class
to fail. Instead, only that field or base class becomes inaccessible
from Carbon.

Also improve the way that type importing errors are diagnosed. While we
lose the precision of a diagnostic saying why a type is not supported,
we gain a useful source location for where the type was mentioned in C++
code.

---------

Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2025-08-13 22:07:54 +00:00
Jon Ross-Perkins b410ebd088 Fix destruction of generic types (#5943)
The self access is important; for the test `generic_class.carbon` being
added to `toolchain/check/testdata/class/destroy_calls.carbon`, it was
using `%T.as.Destroy` instead of `%D.as.Destroy`, indicating the default
blank impl was being used instead of the type-specific version. That
test is trying to focus on the issue, but the delta is visible in a
couple other files in this PR, for example
`toolchain/check/testdata/class/generic/init.carbon`.

I'm separately working on getting rid of the default impl, which is how
I noticed this.
2025-08-12 00:10:43 +00:00
Jon Ross-Perkins 55085de6aa Use GetStructType when building object repr structs (#5923)
I was thinking about this for destruction, which I may not be able to
use it for, but still think this may be a good change to keep features
consistent.
2025-08-06 23:55:05 +00:00
Boaz Brickner 1d314c7c4d Import C++ constructors of class Type fn Type(...) -> Type (#5879)
Only supports classes with a single (non copy non move) constructor
(without default values), until overloading is supported.

Based on #5878.

C++ Interop Demo:

```c++
// hello_world.h

#include <cstdio>

class C {
 public:
  C(int x, int y) : x_(x), y_(y) {}

  int x() const { return x_;}
  int y() const { return y_;}

 private:
  int x_;
  int y_;
};

void hello_world(C* _Nonnull c);
```

```c++
// hello_world.cpp

#include "hello_world.h"

#include <cstdio>

void hello_world(C* _Nonnull c) {
  printf("C.x = %d. C.y = %d\n", c->x(), c->y());
}
```

```carbon
// main.carbon

library "Main";

import Cpp library "hello_world.h";

fn Run() -> i32 {
  var c : Cpp.C = Cpp.C.C(1, 2);
  Cpp.hello_world(&c);
  return 0;
}
```

```shell
$ clang -c hello_world.cpp
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link hello_world.o main.o --output=demo
$ ./demo
C.x = 1. C.y = 2
```

Part of #5880.
2025-08-06 12:02:38 +00:00
Jon Ross-PerkinsandGeoff Romer 7209ad7c9f Generate Destroy impls for classes (#5873)
Although this focused on `Destroy` support, some choices here around
`implicit_type_impls` are because copy/move will likely follow a similar
approach. I'm trying not to predict too much about how we'll structure
those, but I'm putting `Destroy` impl logic in a file that could perhaps
be shared with those. They'd likely be interested in similar things,
e.g. traversing members of types (particularly class, struct literal,
tuple literal).

At present this sets the destroy function as `no_op` which is consistent
with current logic, but has a TODO to correctly define.

Constant importing for functions changes slightly due to some issues I
was having with `GetFunctionType`. zygoloid suggested this approach to
avoid `EvalInst` logic.

Adds a flag for controlling whether to generating these impls. While
this does generation for `class`, as noted above this'll also need to be
done for tuples and struct literals, which would leave the `none.carbon`
min_prelude unable to use any types. Note if destruction *would* occur,
it'll still look up `Core.Destroy` for that and fail, but that's already
true of any test using `none.carbon`. I'm trying to use the flag to see
if we can keep `none.carbon` working mostly-consistently.

I'd tried separating out the flag to #5852, but that got a lot of
pushback over whether the behavior was appropriate. I'm hoping that the
interactions here make it clearer why the particular approach -- the
goal is not to enable advanced testing, or create some new end-user
behavior that we really support, it's just to keep no-prelude tests
functional. The main question raised there was why not just keep
generating `impl T as Core.Destroy` if `fn destroy` is present -- but I
think here it should be apparent that would require additional
complexity, as the generation of `impl T as Core.Destroy` is not
currently conditioned based on the implementation of `fn destroy`. I'd
rather add complexity to this flag only if it's enabling interesting
test functionality.

---------

Co-authored-by: Geoff Romer <gromer@google.com>
2025-08-04 19:39:22 +00:00
Boaz Brickner 7de86a0b10 Move and deduplicate testing access when a Carbon class extends a C++ record to access.carbon (#5897)
Followup of #5858.
Part of #5859.
2025-08-01 13:44:08 +00:00
Richard Smith 25681901bd Improve mapping of Clang diagnostics into Carbon diagnostics (#5894)
Instead of taking the complete text of the Clang diagnostic and using it
as the message portion of a Carbon diagnostic, generate the individual
pieces separately and pass them into the Carbon diagnostic
infrastructure.

* Clang's context lines are generated by running a custom "diagnostic
renderer" and tracking which lines it wants to print as context for a
given source location. When mapping from a C++ source location back to a
Carbon location, the Carbon `Loc` structure is now fully populated,
including filling in the context line and the column number.
* Clang's snippet is generated by running a custom diagnostic renderer
that is a cut-down version of the full text diagnostic renderer that
only prints a snippet. This is then attached to the Carbon diagnostic
manually as an override for the snippet we'd usually create.

We no longer repeat the file location twice on each diagnostic, and no
longer produce a bogus "in import" line for all locations coming from
clang that point arbitrarily to the first C++ import in the Carbon file.
The `[diagnostic kind]` marker is now displayed at the end of the
diagnostic message, not on a line of its own after the snippet.
2025-08-01 01:24:31 +00:00
Richard SmithandChandler Carruth b320ea77ec Improve source location in an import error. (#5887)
When attempting to import a definition of a class with virtual bases,
diagnose the point of use instead of the point of definition of the
class.

---------

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2025-07-31 00:45:38 +00:00
Richard Smith ae16014df8 Don't import a C++ class definition until the class is required to be complete. (#5865)
When importing a class definition, ask Clang to complete it first. This
causes class template specializations to get instantiated as needed when
the type-checking of Carbon requires a C++ class to be complete. It also
allows Clang to implement things like modules-aware definition
visibility checking.

Don't reject importing a class with a virtual base if it's never
required to be complete. Instead, defer diagnosing until the definition
is required.

This also removes the recursion from `MapType`, as mapping a class type
no longer maps its definition.

In order to get diagnostics from instantiation failures, fix a bug that
caused any Clang diagnostics produced after the initial building of the
`ASTUnit` to get discarded. This exposed some duplicate diagnostic
issues in `ImportNameFromCpp` which are fixed here too.
2025-07-30 23:34:18 +00:00
Boaz Brickner 6a3e222fb7 Don't ignore SemIR ranges in C++ interop tests (#5877)
The non failing tests already define ranges.
2025-07-30 17:17:37 +00:00
Richard Smith a6f5143f22 Fix diagnostic for access of protected/private base member. (#5874)
When importing the member, import the access level for the lookup
result, not the declared access of the member declaration.
2025-07-30 17:17:09 +00:00
Richard Smith ef475d8197 Import C++ class A final as Carbon final class. (#5866)
Also import unions as final classes, and abstract classes as `abstract
class`es.
2025-07-30 00:41:42 +00:00
Boaz Brickner 30f0ddab71 Add support for importing access from C++ to Carbon (#5858)
Better access control with inheritance should come with better
inheritance support (actually importing inheritance).

C++ Interop Demo:

```c++
// hello_world.h

class HelloWorld {
 public:
  static auto Pub() -> void;

 protected:
  static auto Pro() -> void;

 private:
  static auto Pri() -> void;
};
```

```c++
// hello_world.cpp

#include "hello_world.h"

#include <cstdio>

auto HelloWorld::Pub() -> void { printf("Public!\n"); }
auto HelloWorld::Pro() -> void { printf("Protected!\n"); }
auto HelloWorld::Pri() -> void { printf("Private!\n"); }
```

```carbon
// main.carbon

library "Main";

import Cpp library "hello_world.h";

fn Run() -> i32 {
  Cpp.HelloWorld.Pub();
  Cpp.HelloWorld.Pro();
  Cpp.HelloWorld.Pri();
  return 0;
}
```

```shell
$ clang -c hello_world.cpp
$ bazel-bin/toolchain/carbon compile main.carbon
main.carbon:9:3: error: cannot access protected member `Pro` of type `Cpp.HelloWorld`
  Cpp.HelloWorld.Pro();
  ^~~~~~~~~~~~~~~~~~
main.carbon: note: declared here

main.carbon:10:3: error: cannot access private member `Pri` of type `Cpp.HelloWorld`
  Cpp.HelloWorld.Pri();
  ^~~~~~~~~~~~~~~~~~
main.carbon: note: declared here
```

Before this change (no access checks):
```shell
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link hello_world.o main.o --output=demo
$ ./demo
Public!
Protected!
Private!
```

Part of #5859.
2025-07-29 08:25:15 +00:00
Richard Smith 5de47962b0 Support for importing C++ base classes. (#5856)
For now, provide no support for virtual base classes and only minimal
support for multiple inheritance.
2025-07-28 20:56:06 +00:00
Richard Smith 0d74162e2a Support C++ import for anonymous struct and union members. (#5855) 2025-07-28 20:26:24 +00:00
Richard Smith 36f0a73092 Initial support for interop with class/struct/union fields. (#5849)
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.
2025-07-25 21:09:24 +00:00
Jon Ross-Perkins 7ccc1e0144 Expand naming for impls and functions (#5808)
Change impls from `<interface>.impl` to `<self>.as.<interface>.impl`,
and *member* functions to `<parent scope>.<fn>` (non-member functions
exclude their parent scope). Stop special-casing builtin functions,
given the new naming scheme.

The purpose of this is to make it clearer when a member function is
being accessed and, if so, which member function. In particular, we
often access interface `Op` functions. The builtin function
special-casing was intended to help with that, but we still have lots of
`Op` functions. This particular approach should make the interactions
clearer.

This changes up queueing of block IDs a little because, in particular,
we need to process bodies of entities only after constants finish
processing. But, it should also result in less memory usage during
processing because it means we have less on the insts stack at any given
time, since we track a block rather than all instructions contained by
the block.
2025-07-21 18:45:07 +00:00
Jon Ross-PerkinsandGeoff Romer eae3491129 Switch inst namer to queue entities when reached (#5806)
This switches from the `CollectNamesInBlock` approach for entities, to
instead traversing entities as they're encountered. For example, when
traversing constants, when a type is found, the entity will have its
block queued for processing.

This leads to a change in the traversal order, which affects
disambiguation done by numeric sequencing (since that's just showing the
traversal order).

This will allow for simpler "name based on name" logic. This is
something I plan to use for:

- impls: `<type>.as.<interface>.impl`
- functions: `<entity>.<member function>`
  - Note an impl may be used as the entity for a bound function.

By naming the entities as they're encountered, I'll be able to rely on
the generated names rather than recalculating them.

To assist this, I'm also differentiating between the ambiguous and
disambiguated name. Otherwise, we could end up with things like
`<function>.<disambiguator>.<call>.<other disambiguator>`, where the
repeated disambiguator may not be necessary in order to get full
disambiguation. It's also a smaller delta from the current output.

Note, changing `Name` to a class felt appropriate given its shape. I was
also noticing that parts of its API were unused, and the class helps
detect unused private members.

---------

Co-authored-by: Geoff Romer <gromer@google.com>
2025-07-21 17:58:55 +00:00
Boaz Brickner 4f8d0649d5 When importing a looked up name, reuse previously imported declaration instead of importing the same declaration again (#5789)
Added test coverage to demonstrate name lookup following import of a
type of a function parameter.
SemIR changes show that the same decl isn't imported multiple times.

Part of #5533.
2025-07-16 11:21:49 +00:00
Richard Smith f204bdf094 Basic support for calling class methods imported from C++. (#5796)
Create a `self` parameter when importing a C++ non-static member
function. That seems to be all we need to get basic method calls
working! For now, `const` methods have by-value self parameters, and
non-`const` methods get an `addr self: Self*` parameter.
2025-07-15 16:05:01 +00:00