[CodeGen] Don't make availability attributes imply default visibility on macos

[erik.pilkington]

Summary

Previously, the presence of __attribute__((availability(macos, ...))) on a declaration caused clang to make the vis of that decl implicitly default. This is a hack that is incomparable with how we're treating availability attributes now, and should be removed.

Thanks for taking a look!
Erik

[arphaman]

LGTM. Please document this change in the release notes.

[thakis]

Awesome, thanks! Maybe mention the PR# for this in the commit message.

[thakis]

Is landing this blocked on internal testing?

[thakis]

What's the status here?

[thakis]

Err sorry, landed in rL310382.

cfe/trunk/docs/ReleaseNotes.rst

 -----------------------
 
 Clang now supports the ...
 
 
 Attribute Changes in Clang
 --------------------------
 
+- The presence of __attribute__((availability(...))) on a declaration no longer
+  implies default visibility for that declaration on macOS.
+
 - ...
 
 Windows Support
 ---------------
 
 Clang's support for building native Windows programs ...
 
 

cfe/trunk/lib/AST/Decl.cpp

if (kind == NamedDecl::VisibilityForType) {
     }
   }
 
   // If this declaration has an explicit visibility attribute, use it.
   if (const auto *A = D->getAttr<VisibilityAttr>()) {
     return getVisibilityFromAttr(A);
   }
 
-  // If we're on Mac OS X, an 'availability' for Mac OS X attribute
-  // implies visibility(default).
-  if (D->getASTContext().getTargetInfo().getTriple().isOSDarwin()) {
-    for (const auto *A : D->specific_attrs<AvailabilityAttr>())
-      if (A->getPlatform()->getName().equals("macos"))
-        return DefaultVisibility;
-  }
-
   return None;
 }
 
 static LinkageInfo
 getLVForType(const Type &T, LVComputationKind computation) {
   if (computation == LVForLinkageOnly)
     return LinkageInfo(T.getLinkage(), DefaultVisibility, true);
   return T.getLinkageAndVisibility();

cfe/trunk/test/CodeGen/attr-availability.c

 // RUN: %clang_cc1 -fvisibility hidden "-triple" "x86_64-apple-darwin8.0.0" -emit-llvm -o - %s | FileCheck -check-prefix=CHECK-10_4 %s
 // RUN: %clang_cc1 -fvisibility hidden "-triple" "x86_64-apple-darwin9.0.0" -emit-llvm -o - %s | FileCheck -check-prefix=CHECK-10_5 %s
 // RUN: %clang_cc1 -fvisibility hidden "-triple" "x86_64-apple-darwin10.0.0" -emit-llvm -o - %s | FileCheck -check-prefix=CHECK-10_6 %s
 
 // CHECK-10_4-LABEL: define hidden void @f2
 // CHECK-10_5-LABEL: define hidden void @f2
 // CHECK-10_6-LABEL: define hidden void @f2
 void f2();
 void f2() { }
 
-// CHECK-10_4-LABEL: define void @f3
-// CHECK-10_5-LABEL: define void @f3
-// CHECK-10_6-LABEL: define void @f3
+// CHECK-10_4-LABEL: define hidden void @f3
+// CHECK-10_5-LABEL: define hidden void @f3
+// CHECK-10_6-LABEL: define hidden void @f3
 void f3() __attribute__((availability(macosx,introduced=10.5)));
 void f3() { }
 
 // CHECK-10_4: declare extern_weak void @f0
 // CHECK-10_5: declare void @f0
 // CHECK-10_6: declare void @f0
 void f0() __attribute__((availability(macosx,introduced=10.5)));