[clang] Add __has_feature(swiftcc) that checks whether the target supports the Swift calling convention

[kubamracek]

No description provided.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Kuba (Brecka) Mracek (kubamracek)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/72159.diff

1 Files Affected:

• (modified) clang/include/clang/Basic/Features.def (+3)

diff --git a/clang/include/clang/Basic/Features.def b/clang/include/clang/Basic/Features.def
index da77aee8de36990..f69d52a0c24f88e 100644
--- a/clang/include/clang/Basic/Features.def
+++ b/clang/include/clang/Basic/Features.def
@@ -99,6 +99,9 @@ FEATURE(memory_sanitizer,
 FEATURE(thread_sanitizer, LangOpts.Sanitize.has(SanitizerKind::Thread))
 FEATURE(dataflow_sanitizer, LangOpts.Sanitize.has(SanitizerKind::DataFlow))
 FEATURE(scudo, LangOpts.Sanitize.hasOneOf(SanitizerKind::Scudo))
+FEATURE(swiftcc,
+  PP.getTargetInfo().checkCallingConvention(CC_Swift) ==
+  clang::TargetInfo::CCCR_OK)
 FEATURE(swiftasynccc,
   PP.getTargetInfo().checkCallingConvention(CC_SwiftAsync) ==
   clang::TargetInfo::CCCR_OK)

[AaronBallman]

This is not a FEATURE, it's an EXTENSION:

llvm-project/clang/include/clang/Basic/Features.def

Line 20 in 33374c4

// FEATURE(...) should be used to advertise support for standard language

I think the other swift calling convention should be fixed at the same time, that looks like a simple oversight.

[AaronBallman]

The changes also need to come with a test and a release note.