Implement a new 'availability' attribute, that allows one to specify

which versions of an OS provide a certain facility. For example,

  void foo()
  __attribute__((availability(macosx,introduced=10.2,deprecated=10.4,obsoleted=10.6)));

says that the function "foo" was introduced in 10.2, deprecated in
10.4, and completely obsoleted in 10.6. This attribute ties in with
the deployment targets (e.g., -mmacosx-version-min=10.1 specifies that
we want to deploy back to Mac OS X 10.1). There are several concrete
behaviors that this attribute enables, as illustrated with the
function foo() above:

  - If we choose a deployment target >= Mac OS X 10.4, uses of "foo"
    will result in a deprecation warning, as if we had placed
    attribute((deprecated)) on it (but with a better diagnostic)
  - If we choose a deployment target >= Mac OS X 10.6, uses of "foo"
    will result in an "unavailable" warning (in C)/error (in C++), as
    if we had placed attribute((unavailable)) on it
  - If we choose a deployment target prior to 10.2, foo() is
    weak-imported (if it is a kind of entity that can be weak
    imported), as if we had placed the weak_import attribute on it.

Naturally, there can be multiple availability attributes on a
declaration, for different platforms; only the current platform
matters when checking availability attributes.

The only platforms this attribute currently works for are "ios" and
"macosx", since we already have -mxxxx-version-min flags for them and we
have experience there with macro tricks translating down to the
deprecated/unavailable/weak_import attributes. The end goal is to open
this up to other platforms, and even extension to other "platforms"
that are really libraries (say, through a #pragma clang
define_system), but that hasn't yet been designed and we may want to
shake out more issues with this narrower problem first.

Addresses <rdar://problem/6690412>.

As a drive-by bug-fix, if an entity is both deprecated and
unavailable, we only emit the "unavailable" diagnostic.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@128127 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 17 deletions

diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index 110f8cdc1c..7a4e68d3cb 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -6282,8 +6282,7 @@ OverloadCandidateSet::BestViableFunction(Sema &S, SourceLocation Loc,
 
   // Best is the best viable function.
   if (Best->Function &&
-      (Best->Function->isDeleted() ||
-       Best->Function->getAttr<UnavailableAttr>()))
+      (Best->Function->isDeleted() || Best->Function->isUnavailable()))
     return OR_Deleted;
 
   return OR_Success;
@@ -6735,7 +6734,7 @@ void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand,
   FunctionDecl *Fn = Cand->Function;
 
   // Note deleted candidates, but only if they're viable.
-  if (Cand->Viable && (Fn->isDeleted() || Fn->hasAttr<UnavailableAttr>())) {
+  if (Cand->Viable && (Fn->isDeleted() || Fn->isUnavailable())) {
     std::string FnDesc;
     OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, FnDesc);
 
@@ -7744,8 +7743,7 @@ Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE,
       Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_deleted_call)
         << Best->Function->isDeleted()
         << ULE->getName()
-        << Best->Function->getMessageUnavailableAttr(
-             !Best->Function->isDeleted())
+        << getDeletedOrUnavailableSuffix(Best->Function)
         << Fn->getSourceRange();
       CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args, NumArgs);
     }
@@ -7928,8 +7926,7 @@ Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, unsigned OpcIn,
       Diag(OpLoc, diag::err_ovl_deleted_oper)
         << Best->Function->isDeleted()
         << UnaryOperator::getOpcodeStr(Opc)
-        << Best->Function->getMessageUnavailableAttr(
-             !Best->Function->isDeleted())
+        << getDeletedOrUnavailableSuffix(Best->Function)
         << Input->getSourceRange();
       CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args, NumArgs);
       return ExprError();
@@ -8199,8 +8196,7 @@ Sema::CreateOverloadedBinOp(SourceLocation OpLoc,
       Diag(OpLoc, diag::err_ovl_deleted_oper)
         << Best->Function->isDeleted()
         << BinaryOperator::getOpcodeStr(Opc)
-        << Best->Function->getMessageUnavailableAttr(
-             !Best->Function->isDeleted())
+        << getDeletedOrUnavailableSuffix(Best->Function)
         << Args[0]->getSourceRange() << Args[1]->getSourceRange();
       CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args, 2);
       return ExprError();
@@ -8349,8 +8345,7 @@ Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
     case OR_Deleted:
       Diag(LLoc, diag::err_ovl_deleted_oper)
         << Best->Function->isDeleted() << "[]"
-        << Best->Function->getMessageUnavailableAttr(
-             !Best->Function->isDeleted())
+        << getDeletedOrUnavailableSuffix(Best->Function)
         << Args[0]->getSourceRange() << Args[1]->getSourceRange();
       CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args, 2,
                                   "[]", LLoc);
@@ -8468,8 +8463,7 @@ Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE,
       Diag(UnresExpr->getMemberLoc(), diag::err_ovl_deleted_member_call)
         << Best->Function->isDeleted()
         << DeclName 
-        << Best->Function->getMessageUnavailableAttr(
-             !Best->Function->isDeleted())
+        << getDeletedOrUnavailableSuffix(Best->Function)
         << MemExprE->getSourceRange();
       CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args, NumArgs);
       // FIXME: Leaking incoming expressions!
@@ -8643,8 +8637,7 @@ Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object,
          diag::err_ovl_deleted_object_call)
       << Best->Function->isDeleted()
       << Object->getType() 
-      << Best->Function->getMessageUnavailableAttr(
-           !Best->Function->isDeleted())
+      << getDeletedOrUnavailableSuffix(Best->Function)
       << Object->getSourceRange();
     CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args, NumArgs);
     break;
@@ -8852,8 +8845,7 @@ Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc) {
     Diag(OpLoc,  diag::err_ovl_deleted_oper)
       << Best->Function->isDeleted()
       << "->" 
-      << Best->Function->getMessageUnavailableAttr(
-             !Best->Function->isDeleted())
+      << getDeletedOrUnavailableSuffix(Best->Function)
       << Base->getSourceRange();
     CandidateSet.NoteCandidates(*this, OCD_AllCandidates, &Base, 1);
     return ExprError();