mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 21:50:14 +01:00
Nicholas Bishop
c8fdeef911
This allows C++ to call Carbon functions with generic type parameters,
with some conditions. Example:
```carbon
interface I {
fn Doit(self);
}
class A {
impl as I { fn Doit(unused self) {} }
}
class B {
impl as I { fn Doit(unused self) {} }
}
fn F[T:! I](t: T) {
t.Doit();
}
inline Cpp '''
void G() {
Carbon::A a;
Carbon::B b;
Carbon::F(a);
Carbon::F(b);
}
''';
```
The initial support is limited; only explicit parameters are handled
currently.
`CarbonExternalASTSource::GetOrExportFunctionToCpp` now generates a
`clang::FunctionTemplateDecl` for generic Carbon functions. If C++ code
attempts to call that templated function,
`CarbonExternalASTSource::LoadExternalSpecializations` will be called
with the template argument types of that call site. Then we can generate
a specialized thunk for those argument types for C++ to call.
114 lines
2.3 KiB
Plaintext
114 lines
2.3 KiB
Plaintext
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/int.carbon
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//
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// AUTOUPDATE
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// TIP: To test this file alone, run:
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// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/export/function.carbon
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// TIP: To dump output, run:
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// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/export/function.carbon
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// --- other.carbon
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package Other;
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fn F1() {}
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fn F2() -> i32 { return 0; }
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fn F3(_: i32) {}
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fn HasGenericArg(T:! type, a: T) { a; }
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fn HasDeducedArg[T:! type](a: T) { a; }
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// --- function.carbon
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library "[[@TEST_NAME]]";
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import Other;
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import Cpp inline '''
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void G() {
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Carbon::Other::F1();
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}
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''';
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// --- return_int.carbon
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library "[[@TEST_NAME]]";
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import Other;
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import Cpp inline '''
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int G() {
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return Carbon::Other::F2();
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}
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''';
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// --- args.carbon
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library "[[@TEST_NAME]]";
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import Other;
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import Cpp inline '''
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void G() {
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Carbon::Other::F3(123);
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}
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''';
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// --- ref_arg.carbon
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library "[[@TEST_NAME]]";
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import Cpp;
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fn F(ref n: i32);
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inline Cpp '''
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void G() {
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int n = 0;
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Carbon::F(n);
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}
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''';
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// --- using.carbon
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library "[[@TEST_NAME]]";
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import Cpp;
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fn F();
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inline Cpp '''
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using Carbon::F;
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void G() { F(); }
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''';
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// --- fail_todo_generic.carbon
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library "[[@TEST_NAME]]";
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// CHECK:STDERR: fail_todo_generic.carbon:[[@LINE+9]]:1: in import [InImport]
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// CHECK:STDERR: other.carbon:7:1: error: 1 argument passed to function expecting 2 arguments [CallArgCountMismatch]
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// CHECK:STDERR: fn HasGenericArg(T:! type, a: T) { a; }
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// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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// CHECK:STDERR: fail_todo_generic.carbon:[[@LINE+5]]:1: in import [InImport]
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// CHECK:STDERR: other.carbon:7:1: note: calling function declared here [InCallToEntity]
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// CHECK:STDERR: fn HasGenericArg(T:! type, a: T) { a; }
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// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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// CHECK:STDERR:
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import Other;
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import Cpp inline '''
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void G() {
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Carbon::Other::HasGenericArg<int>(123);
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}
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''';
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// --- deduced.carbon
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library "[[@TEST_NAME]]";
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import Other;
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import Cpp inline '''
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void G() {
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Carbon::Other::HasDeducedArg(123);
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}
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''';
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