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.
Expand support for `int` and `short` to cover all the other `intN_t` and
`uintN_t` types too. We achieve this by asking Clang what the `intN_t` /
`uintN_t` type that it would use for the given bitwidth is, and checking
if that's the type we're trying to map.
Before this change we crash in this case when trying to use the outer
type.
After this change we diagnose a TODO.
Will add the missing support for this in a separate PR.
Part of #5533.
For example, this would allow using `std::string::size`, which is
templated because it's a member of the class template
`std::basic_string`, but isn't itself a function template.
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.
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.
Incidentally also supports import of pointers-to-pointers.
Imported const-qualified types aren't especially useful just yet,
because on the Carbon side we don't yet permit conversions from
non-const to const types, so most of the tests still fail, but for
different reasons now.
Unify code paths for importing classes by name and importing them
indirectly when their type is referenced. Switch to using the general
type import machinery to import all type declarations, which allows
typedef declarations naming importable types to be used too.
Fix up handling of error cases to consistently only produce an Error
InstId after actually producing an error message, so that we can produce
exactly one diagnostic in failure cases.
Remove TODO error for unions that previously was only produced when
importing them indirectly, not when importing them by name. Import of
unions is exactly as complete / incomplete as import of other class
types, so treating them differently doesn't seem necessary.
Stop using the clang tooling library to build an ASTUnit; that library
is set up to process clang frontend arguments, assuming that something
has already built frontend arguments from the compiler arguments. It is
also too encapsulated and doesn't let us inspect and modify the compiler
invocation before it's executed.
Instead, build the AST unit directly in two phases:
* FIrst, take a list of clang driver arguments and convert them into a
list of compiler arguments, using `clang::createInvocation`. Internally,
this uses the clang driver to build a frontend invocation, including
building system-specific include paths as needed.
* Then, directly build an ASTUnit from this compiler invocation.
I've factored this so that we can split out the `createInvocation` step,
with the intention that we may want to move it out of check and into the
carbon driver with the rest of the driver-level argument handling, and
we may want to customize some of the clang options before we invoke the
clang frontend with that set of options.
In order to make the invocation reusable, it no longer depends on the
name of the carbon file importing the C++ code. In place of synthesizing
a header file name as `<foo.carbon>.generated.cpp_imports.h`, we now
insert line marker directives into the generated header so that errors
in that header cause Clang to point a diagnostic back at the Carbon
source file itself. This results in a minor improvement in the
diagnostic output: we no longer refer to a nonexistent generated file.
But the snippet still contains text that doesn't match the source code,
so it remains imperfect.
---------
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
When diagnosing a problem with C++ code imported from Carbon, include
the location of the specific `import Cpp` statement that imported the
C++ code as part of the backtrace, rather than providing a location in a
generated file that doesn't exist on disk.
Also fix handling in autoupdate of check lines that contain multiple
file name and line number pairs to use the matched file name for
remapping of locations rather than the first file name in the line.
When mapping parameter types, we assume that if the `clang::Decl` isn't
mapped, the name wasn't added, so this fixes a bug that triggers a crash
otherwise.
Part of #5533.
The `ClangDecl` struct caused some confusion here -- it is embedding
extra data into a `CanonicalValueStore` that isn't used for lookups or
canonicalization, but is useful to store along side. This changes the
`CanonicalValueStore` to support customized key type for `Lookup` so
that we can provide the more direct API that only takes the relevant
key.
This in turn takes advantage of the support for heterogenous keys in the
underlying `Set` as long as hashing and equality are consistent. We do
need to add support for heterogenous equality comparison with
`clang::Decl*`, but that is fairly easily done now that the
argument-reversed form isn't needed as well.
Lastly, this cleans up the `ClangDecl` customization points to be more
idiomatic by using `operator==` and `CarbonHashValue`. While there, I've
added comments to make it unambiguous why we can use the pointer value
for the underlying `clang::Decl` due to the Clang AST's
address-as-identity model.
Resolves the immediate TODOs around this type.
Future work might involve changing from the current `Add` API to one
more like `Map` and `Set`'s API where a callback is used to create the
object, but that level of API complexity isn't necessarily motivated yet
and can easily be a follow-on if and when its worth doing. The `Add`
code paths *are* working with the `inst_id` in order to create an
instruction if we are importing the Clang declaration. It is the
`Lookup` code paths that never needed to know about the `inst_id` and
became more confusing for having to stub it out in the API.
---------
Co-authored-by: Geoff Romer <gromer@google.com>
This doesn't support actually passing the value of the struct, which is
planned to be implemented using thunks.
`ClangDeclId` value is now `ClangDecl` which includes the mapped Carbon
instruction in addition to the Clang declaration. This allows finding
the Carbon instruction for a given Clang declaration, which is necessary
for mapping a Clang struct parameter type to the Carbon class without
doing name lookup. We don't take the instruction as part of the hash
key, as discussed in
[Discord](https://discord.com/channels/655572317891461132/768530752592805919/1380575881050718469).
To map the type, we also need to map namespaces. To avoid recursion for
inner namespaces, we use a vector.
Note that the first commit just changes the order of functions in the
file to make review easier.
C++ Interop Demo (that shows missing behavior):
```c++
// hello_world.h
struct S {
S(const S&) { x = 1; }
int x;
};
void hello_world(S s);
```
```c++
// hello_world.cpp
#include "hello_world.h"
#include <cstdio>
void hello_world2(S s) { printf("hello_world2: %d\n", s.x); }
void hello_world(S s) {
printf("hello_world: %d\n", s.x);
hello_world2(s);
}
```
```carbon
// main.carbon
library "Main";
import Cpp library "hello_world.h";
fn Run() -> i32 {
var s : Cpp.S;
Cpp.hello_world(s);
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
hello_world: -1108224096
hello_world2: 1
```
Part of #5533.
I believe we will need to eventually add the specific C++ import
information in `LocId`.
This also seems to fix the `LanguageServerDiagnosticInWrongFile` issue
(#5604).
We're still not in the state we want to be according to
https://github.com/carbon-language/carbon-lang/pull/5246#issuecomment-2784301206.
Will look into removing the location part from the `"In file included
from ..."` line.
Part of #5245.
I've been mulling the name of this, changing it and updating comments to
try and better reflect the current semantic. "Imports" reflects how
we're currently printing this in SemIR.
This mirrors how imports work in general, that the imported declarations
shouldn't belong to the first referencing scope (particularly apparent
when referenced across multiple scopes). I think this was just an
oversight here.
In LLVM, CLANG_DEFAULT_PIE_ON_LINUX is
[configurable](https://github.com/llvm/llvm-project/blob/main/clang/test/CMakeLists.txt#L8),
so change lowering to specify a value.
Also, adjust how the target is set so that function_decl.carbon isn't
trying to overload every flag, and so that the target isn't forgotten
elsewhere.
This is fixing issues introduced by #5427; note #5520 is also a related
fix.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
This requires:
* Making `FunctionDecl` mutable since generating code
(`HandleTopLevelDecl()`) requires a mutable declaration and since we
manually add `used` attribute to force code generation.
* Passing the file system to `Lower` since it's needed by Clang code
generation.
* Creating an internal Clang LLVM module and link it against the Carbon
LLVM module.
Demo:
```c++
// hello_world.h
extern int puts;
inline void hello_world() {
((int (*)(const char*))&puts)("hello world");
}
```
```carbon
// main.carbon
library "Main";
import Cpp library "hello_world.h";
fn Run() -> i32 {
Cpp.hello_world();
return 0;
}
```
```shell
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link main.o --output=demo
$ ./demo
hello world
```
Based on https://github.com/carbon-language/carbon-lang/pull/5406.
Part of #5405.
Fixes a compile failure with the new version, essentially:
```
external/+llvm_project+llvm-project/llvm/include/llvm/Support/FormatVariadicDetails.h:157:1: error: implicit instantiation of undefined template 'llvm::support::detail::missing_format_adapter<clang::LookupResultKind>'
```
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`.
TypeInstId is an InstId whose constant value has a type of TypeType.
This includes:
- Type value instructions, the `ClassType` or `IntLiteralType`
instructions.
- Constraint value instructions, which are the `FacetType` and
`TypeType` instructions, each of which also have type TypeType.
TypeInstId encodes in the type system that it is safe to convert the
instruction's value to a TypeId, and CHECKs at construction that this
invariant is maintained.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
In preparation for shifting from `TypeId`s potentially representing
attached types to always representing unattached types, using
[terminology suggested on
Discord](https://discord.com/channels/655572317891461132/963846118964350976/1359286326779973712).
This change causes us to track slightly more type spelling information
through SemIR.
One change that has significant impact on the SemIR output is that we
now build a `struct_type` instruction in each class representing the
types of the fields, including the spelling used for those types. This
is now no longer always identical to the corresponding canonical
`struct_type` for the object representation, so it's built separately
and owned by the class.
Also remove `TypeBlock` support entirely, as its only use was
representing `TupleType`s, which now use an `InstBlock`.
Boaz Brickner
Richard Smith
Ivana Ivanovska
Jon Ross-Perkins
josh11bandJosh L
Dana Jansens
Thomas Köppe