Add 'nopartial' qualifier for availability attributes.

An optional nopartial can be placed after the platform name.
int bar() __attribute__((availability(macosx,nopartial,introduced=10.12))

When deploying back to a platform version prior to when the declaration was
introduced, with 'nopartial', Clang emits an error specifying that the function
is not introduced yet; without 'nopartial', the behavior stays the same: the
declaration is `weakly linked`.

A member is added to the end of AttributeList to save the location of the
'nopartial' keyword. A bool member is added to AvailabilityAttr.

The diagnostics for 'nopartial' not-yet-introduced is handled in the same way as
we handle unavailable cases.

Reviewed by Doug Gregor and Jordan Rose.

rdar://23791325

llvm-svn: 261163

1 files changed, 19 insertions, 5 deletions

diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 900c33b7911..c766ef30e62 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -833,11 +833,14 @@ VersionTuple Parser::ParseVersionTuple(SourceRange &Range) {
 /// \brief Parse the contents of the "availability" attribute.
 ///
 /// availability-attribute:
-///   'availability' '(' platform ',' version-arg-list, opt-message')'
+///   'availability' '(' platform ',' opt-nopartial version-arg-list, opt-message')'
 ///
 /// platform:
 ///   identifier
 ///
+/// opt-nopartial:
+///   'nopartial' ','
+///
 /// version-arg-list:
 ///   version-arg
 ///   version-arg ',' version-arg-list
@@ -867,7 +870,7 @@ void Parser::ParseAvailabilityAttribute(IdentifierInfo &Availability,
     return;
   }
 
-  // Parse the platform name,
+  // Parse the platform name.
   if (Tok.isNot(tok::identifier)) {
     Diag(Tok, diag::err_availability_expected_platform);
     SkipUntil(tok::r_paren, StopAtSemi);
@@ -889,10 +892,12 @@ void Parser::ParseAvailabilityAttribute(IdentifierInfo &Availability,
     Ident_obsoleted = PP.getIdentifierInfo("obsoleted");
     Ident_unavailable = PP.getIdentifierInfo("unavailable");
     Ident_message = PP.getIdentifierInfo("message");
+    Ident_nopartial = PP.getIdentifierInfo("nopartial");
   }
 
-  // Parse the set of introductions/deprecations/removals.
-  SourceLocation UnavailableLoc;
+  // Parse the optional "nopartial" and the set of
+  // introductions/deprecations/removals.
+  SourceLocation UnavailableLoc, NopartialLoc;
   do {
     if (Tok.isNot(tok::identifier)) {
       Diag(Tok, diag::err_availability_expected_change);
@@ -902,6 +907,15 @@ void Parser::ParseAvailabilityAttribute(IdentifierInfo &Availability,
     IdentifierInfo *Keyword = Tok.getIdentifierInfo();
     SourceLocation KeywordLoc = ConsumeToken();
 
+    if (Keyword == Ident_nopartial) {
+      if (NopartialLoc.isValid()) {
+        Diag(KeywordLoc, diag::err_availability_redundant)
+          << Keyword << SourceRange(NopartialLoc);
+      }
+      NopartialLoc = KeywordLoc;
+      continue;
+    }
+
     if (Keyword == Ident_unavailable) {
       if (UnavailableLoc.isValid()) {
         Diag(KeywordLoc, diag::err_availability_redundant)
@@ -1023,7 +1037,7 @@ void Parser::ParseAvailabilityAttribute(IdentifierInfo &Availability,
                Changes[Deprecated],
                Changes[Obsoleted],
                UnavailableLoc, MessageExpr.get(),
-               Syntax);
+               Syntax, NopartialLoc);
 }
 
 /// \brief Parse the contents of the "objc_bridge_related" attribute.