carbon-language/carbon-lang
1
0
Fork 0
mirror of https://github.com/carbon-language/carbon-lang.git synced 2026-10-05 22:02:55 +01:00
Code Issues Packages Projects Releases 10 Wiki Activity

Support importing C++ _Nonnull pointers as function parameters or return values (#5773)

Browse Source 
We avoid using canonical type before knowing it's not a pointer because
we need the nullability attribute.
No support for pointers to pointers, yet.

C++ Interop Demo:

```c++
// hello_world.h

auto hello_world_param(int* _Nonnull i) -> void;
auto hello_world_return() -> int* _Nonnull;
```

```c++
// hello_world.cpp

#include "hello_world.h"
#include <cstdio>

auto hello_world_param(int* _Nonnull i) -> void {
  printf("hello_world: %d\n", *i);
}

static int x = 5;
auto hello_world_return() -> int* _Nonnull { return &x; }
```

```carbon
// main.carbon

library "Main";

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

fn Run() -> i32 {
  var i: i32 = 10;
  Cpp.hello_world_param(&i);

  let p: i32* = Cpp.hello_world_return();
  Core.Print(*p);

  return 0;
}
```

```shell
$ clang -c hello_world.cpp
$ ./bazel-bin/toolchain/install/prefix_root/bin/carbon compile main.carbon
$ ./bazel-bin/toolchain/install/prefix_root/bin/carbon link hello_world.o main.o --output=demo
$ ./demo
hello_world: 10
5
```

Part of #5772.
This commit is contained in:
Boaz Brickner
2025-07-10 08:00:37 +00:00
committed by GitHub
parent 110af3bfe4
commit a5ddc3e3cd
7 changed files with 899 additions and 145 deletions
Download Patch File Download Diff File Expand all files Collapse all files
toolchain/check/testdata/interop/cpp/function/union.carbon
Vendored
+27 -20
View File
@@ -29,7 +29,7 @@ import Cpp library "decl_value_param_type.h";
fn F() {
//@dump-sem-ir-begin
// TODO: This should fail on the fact `U` is declared and not defined.
// CHECK:STDERR: fail_todo_import_decl_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_decl_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo({});
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_decl_value_param_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -59,7 +59,7 @@ fn F() {
// CHECK:STDERR: ^
// CHECK:STDERR:
let u: Cpp.U;
// CHECK:STDERR: fail_todo_import_decl_value_param_type_previously_imported.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_decl_value_param_type_previously_imported.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo(u);
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_decl_value_param_type_previously_imported.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -87,7 +87,7 @@ library "[[@TEST_NAME]]";
import Cpp library "double_decl_value_param_type.h";
fn F() {
// CHECK:STDERR: fail_todo_import_double_decl_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_double_decl_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo1({});
// CHECK:STDERR: ^~~~~~~~
// CHECK:STDERR: fail_todo_import_double_decl_value_param_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo1` [InCppNameLookup]
@@ -95,7 +95,7 @@ fn F() {
// CHECK:STDERR: ^~~~~~~~
// CHECK:STDERR:
Cpp.foo1({});
// CHECK:STDERR: fail_todo_import_double_decl_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_double_decl_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo2({});
// CHECK:STDERR: ^~~~~~~~
// CHECK:STDERR: fail_todo_import_double_decl_value_param_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo2` [InCppNameLookup]
@@ -123,7 +123,7 @@ import Cpp library "definition_no_data_members_value_param_type.h";
fn F() {
//@dump-sem-ir-begin
// CHECK:STDERR: fail_todo_import_definition_no_data_members_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_definition_no_data_members_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo({});
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_definition_no_data_members_value_param_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -156,7 +156,7 @@ import Cpp library "definition_single_data_member_value_param_type.h";
fn F() {
//@dump-sem-ir-begin
// CHECK:STDERR: fail_todo_import_definition_single_data_member_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_definition_single_data_member_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo({});
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_definition_single_data_member_value_param_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -191,7 +191,7 @@ import Cpp library "definition_multiple_data_members_value_param_type.h";
fn F() {
//@dump-sem-ir-begin
// CHECK:STDERR: fail_todo_import_definition_multiple_data_members_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_definition_multiple_data_members_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo({});
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_definition_multiple_data_members_value_param_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -220,7 +220,7 @@ import Cpp library "definition_in_namespace_value_param_type.h";
fn F() {
//@dump-sem-ir-begin
// CHECK:STDERR: fail_todo_import_definition_in_namespace_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union N::U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_definition_in_namespace_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: N::U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo({});
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_definition_in_namespace_value_param_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -250,7 +250,7 @@ import Cpp library "definition_in_relative_namespace_value_param_type.h";
fn F() {
//@dump-sem-ir-begin
// CHECK:STDERR: fail_todo_import_definition_in_relative_namespace_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union N1::N2::U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_definition_in_relative_namespace_value_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: N2::U` [SemanticsTodo]
// CHECK:STDERR: Cpp.N1.foo({});
// CHECK:STDERR: ^~~~~~~~~~
// CHECK:STDERR: fail_todo_import_definition_in_relative_namespace_value_param_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -282,7 +282,7 @@ import Cpp library "definition_with_static_method.h";
fn F() {
//@dump-sem-ir-begin
Cpp.U.bar();
// CHECK:STDERR: fail_todo_import_definition_and_static_method_call_before.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_definition_and_static_method_call_before.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo({});
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_definition_and_static_method_call_before.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -301,7 +301,7 @@ import Cpp library "definition_with_static_method.h";
fn F() {
//@dump-sem-ir-begin
// CHECK:STDERR: fail_todo_import_definition_and_static_method_call_after.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_definition_and_static_method_call_after.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo({});
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_definition_and_static_method_call_after.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -321,7 +321,7 @@ fn F() {
union U;
auto foo(U*) -> void;
auto foo(U* _Nonnull) -> void;
// --- fail_todo_import_decl_pointer_param_type.carbon
@@ -338,7 +338,7 @@ import Cpp library "decl_pointer_param_type.h";
// CHECK:STDERR:
fn F(u: Cpp.U*) {
//@dump-sem-ir-begin
// CHECK:STDERR: fail_todo_import_decl_pointer_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union U *` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_decl_pointer_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: U * _Nonnull` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo(u);
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_decl_pointer_param_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -357,7 +357,7 @@ fn F(u: Cpp.U*) {
union U {};
auto foo(U*) -> void;
auto foo(U* _Nonnull) -> void;
// --- fail_todo_import_definition_pointer_param_type.carbon
@@ -367,7 +367,7 @@ import Cpp library "definition_pointer_param_type.h";
fn F(u: Cpp.U*) {
//@dump-sem-ir-begin
// CHECK:STDERR: fail_todo_import_definition_pointer_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: union U *` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_definition_pointer_param_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: parameter type: U * _Nonnull` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo(u);
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_definition_pointer_param_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -396,7 +396,7 @@ import Cpp library "decl_value_return_type.h";
fn F() {
// TODO: This should fail on the fact `U` is declared and not defined.
// CHECK:STDERR: fail_todo_import_decl_value_return_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: return type: union U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_decl_value_return_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: return type: U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo();
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_decl_value_return_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -424,7 +424,7 @@ import Cpp library "definition_value_return_type.h";
fn F() {
//@dump-sem-ir-begin
// CHECK:STDERR: fail_todo_import_definition_value_return_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: return type: union U` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_definition_value_return_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: return type: U` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo();
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_definition_value_return_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -453,7 +453,14 @@ import Cpp library "decl_pointer_return_type.h";
fn F() {
//@dump-sem-ir-begin
// CHECK:STDERR: fail_todo_import_decl_pointer_return_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: return type: union U *` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_decl_pointer_return_type.carbon:[[@LINE+14]]:3: error: semantics TODO: `Unsupported: nullable pointer: U *` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo();
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_decl_pointer_return_type.carbon:[[@LINE+11]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
// CHECK:STDERR: Cpp.foo();
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR:
// CHECK:STDERR: fail_todo_import_decl_pointer_return_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: return type: U *` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo();
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_decl_pointer_return_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]
@@ -472,7 +479,7 @@ fn F() {
union U {};
auto foo() -> U*;
auto foo() -> U* _Nonnull;
// --- fail_todo_import_definition_pointer_return_type.carbon
@@ -482,7 +489,7 @@ import Cpp library "definition_pointer_return_type.h";
fn F() {
//@dump-sem-ir-begin
// CHECK:STDERR: fail_todo_import_definition_pointer_return_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: return type: union U *` [SemanticsTodo]
// CHECK:STDERR: fail_todo_import_definition_pointer_return_type.carbon:[[@LINE+7]]:3: error: semantics TODO: `Unsupported: return type: U * _Nonnull` [SemanticsTodo]
// CHECK:STDERR: Cpp.foo();
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR: fail_todo_import_definition_pointer_return_type.carbon:[[@LINE+4]]:3: note: in `Cpp` name lookup for `foo` [InCppNameLookup]