Split mergeAvailabilityAttr out of handleAvailabilityAttr. This is important

for having a uniform logic for adding attributes to a decl. This in turn
is needed to fix the FIXME:

  // FIXME: This needs to happen before we merge declarations. Then,
  // let attribute merging cope with attribute conflicts.
  ProcessDeclAttributes(S, NewFD, D,
                        /*NonInheritable=*/false, /*Inheritable=*/true);

The idea is that mergeAvailabilityAttr will become a method. Once attributes
are processed before merging, it will be called from handleAvailabilityAttr to
handle multiple attributes in one decl:

void f(int) __attribute__((availability(ios,deprecated=3.0),
                           availability(ios,introduced=2.0)));

and from SemaDecl.cpp to handle multiple decls:

void f(int) __attribute__((availability(ios,deprecated=3.0)));
void f(int) __attribute__((availability(ios,introduced=2.0)));

As a bonus, use the new structure to diagnose incompatible availability
attributes added to different decls (see included testcases).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@156269 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 119 insertions, 40 deletions

diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index af3fabb9d1..c0bc369012 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -1690,64 +1690,143 @@ static void handleObjCRequiresPropertyDefsAttr(Sema &S, Decl *D,
                                  Attr.getRange(), S.Context));
 }
 
-static void handleAvailabilityAttr(Sema &S, Decl *D,
-                                   const AttributeList &Attr) {
-  IdentifierInfo *Platform = Attr.getParameterName();
-  SourceLocation PlatformLoc = Attr.getParameterLoc();
-
+bool checkAvailabilityAttr(Sema &S, SourceRange Range,
+                           IdentifierInfo *Platform,
+                           VersionTuple Introduced,
+                           VersionTuple Deprecated,
+                           VersionTuple Obsoleted) {
   StringRef PlatformName
     = AvailabilityAttr::getPrettyPlatformName(Platform->getName());
-  if (PlatformName.empty()) {
-    S.Diag(PlatformLoc, diag::warn_availability_unknown_platform)
-      << Platform;
-
+  if (PlatformName.empty())
     PlatformName = Platform->getName();
-  }
-
-  AvailabilityChange Introduced = Attr.getAvailabilityIntroduced();
-  AvailabilityChange Deprecated = Attr.getAvailabilityDeprecated();
-  AvailabilityChange Obsoleted = Attr.getAvailabilityObsoleted();
-  bool IsUnavailable = Attr.getUnavailableLoc().isValid();
 
   // Ensure that Introduced <= Deprecated <= Obsoleted (although not all
   // of these steps are needed).
-  if (Introduced.isValid() && Deprecated.isValid() &&
-      !(Introduced.Version <= Deprecated.Version)) {
-    S.Diag(Introduced.KeywordLoc, diag::warn_availability_version_ordering)
-      << 1 << PlatformName << Deprecated.Version.getAsString()
-      << 0 << Introduced.Version.getAsString();
-    return;
+  if (!Introduced.empty() && !Deprecated.empty() &&
+      !(Introduced <= Deprecated)) {
+    S.Diag(Range.getBegin(), diag::warn_availability_version_ordering)
+      << 1 << PlatformName << Deprecated.getAsString()
+      << 0 << Introduced.getAsString();
+    return true;
   }
 
-  if (Introduced.isValid() && Obsoleted.isValid() &&
-      !(Introduced.Version <= Obsoleted.Version)) {
-    S.Diag(Introduced.KeywordLoc, diag::warn_availability_version_ordering)
-      << 2 << PlatformName << Obsoleted.Version.getAsString()
-      << 0 << Introduced.Version.getAsString();
-    return;
+  if (!Introduced.empty() && !Obsoleted.empty() &&
+      !(Introduced <= Obsoleted)) {
+    S.Diag(Range.getBegin(), diag::warn_availability_version_ordering)
+      << 2 << PlatformName << Obsoleted.getAsString()
+      << 0 << Introduced.getAsString();
+    return true;
   }
 
-  if (Deprecated.isValid() && Obsoleted.isValid() &&
-      !(Deprecated.Version <= Obsoleted.Version)) {
-    S.Diag(Deprecated.KeywordLoc, diag::warn_availability_version_ordering)
-      << 2 << PlatformName << Obsoleted.Version.getAsString()
-      << 1 << Deprecated.Version.getAsString();
+  if (!Deprecated.empty() && !Obsoleted.empty() &&
+      !(Deprecated <= Obsoleted)) {
+    S.Diag(Range.getBegin(), diag::warn_availability_version_ordering)
+      << 2 << PlatformName << Obsoleted.getAsString()
+      << 1 << Deprecated.getAsString();
+    return true;
+  }
+
+  return false;
+}
+
+static void mergeAvailabilityAttr(Sema &S, Decl *D, SourceRange Range,
+                                  IdentifierInfo *Platform,
+                                  VersionTuple Introduced,
+                                  VersionTuple Deprecated,
+                                  VersionTuple Obsoleted,
+                                  bool IsUnavailable,
+                                  StringRef Message) {
+  VersionTuple MergedIntroduced;
+  VersionTuple MergedDeprecated;
+  VersionTuple MergedObsoleted;
+  bool FoundAny = false;
+
+  for (specific_attr_iterator<AvailabilityAttr>
+         i = D->specific_attr_begin<AvailabilityAttr>(),
+         e = D->specific_attr_end<AvailabilityAttr>();
+       i != e ; ++i) {
+    const AvailabilityAttr *OldAA = *i;
+    IdentifierInfo *OldPlatform = OldAA->getPlatform();
+    if (OldPlatform != Platform)
+      continue;
+    FoundAny = true;
+    VersionTuple OldIntroduced = OldAA->getIntroduced();
+    VersionTuple OldDeprecated = OldAA->getDeprecated();
+    VersionTuple OldObsoleted = OldAA->getObsoleted();
+    bool OldIsUnavailable = OldAA->getUnavailable();
+    StringRef OldMessage = OldAA->getMessage();
+
+    if ((!OldIntroduced.empty() && !Introduced.empty() &&
+         OldIntroduced != Introduced) ||
+        (!OldDeprecated.empty() && !Deprecated.empty() &&
+         OldDeprecated != Deprecated) ||
+        (!OldObsoleted.empty() && !Obsoleted.empty() &&
+         OldObsoleted != Obsoleted) ||
+        (OldIsUnavailable != IsUnavailable) ||
+        (OldMessage != Message)) {
+      S.Diag(Range.getBegin(), diag::warn_mismatched_availability);
+      S.Diag(OldAA->getLocation(), diag::note_previous_attribute);
+      return;
+    }
+    if (MergedIntroduced.empty())
+      MergedIntroduced = OldIntroduced;
+    if (MergedDeprecated.empty())
+      MergedDeprecated = OldDeprecated;
+    if (MergedObsoleted.empty())
+      MergedObsoleted = OldObsoleted;
+  }
+
+  if (FoundAny &&
+      MergedIntroduced == Introduced &&
+      MergedDeprecated == Deprecated &&
+      MergedObsoleted == Obsoleted)
     return;
+
+  if (MergedIntroduced.empty())
+    MergedIntroduced = Introduced;
+  if (MergedDeprecated.empty())
+    MergedDeprecated = Deprecated;
+  if (MergedObsoleted.empty())
+    MergedObsoleted = Obsoleted;
+
+  if (!checkAvailabilityAttr(S, Range, Platform, MergedIntroduced,
+                             MergedDeprecated, MergedObsoleted)) {
+    D->addAttr(::new (S.Context) AvailabilityAttr(Range, S.Context,
+                                                  Platform,
+                                                  Introduced,
+                                                  Deprecated,
+                                                  Obsoleted,
+                                                  IsUnavailable,
+                                                  Message));
   }
+}
 
+static void handleAvailabilityAttr(Sema &S, Decl *D,
+                                   const AttributeList &Attr) {
+  IdentifierInfo *Platform = Attr.getParameterName();
+  SourceLocation PlatformLoc = Attr.getParameterLoc();
+
+  if (AvailabilityAttr::getPrettyPlatformName(Platform->getName()).empty())
+    S.Diag(PlatformLoc, diag::warn_availability_unknown_platform)
+      << Platform;
+
+  AvailabilityChange Introduced = Attr.getAvailabilityIntroduced();
+  AvailabilityChange Deprecated = Attr.getAvailabilityDeprecated();
+  AvailabilityChange Obsoleted = Attr.getAvailabilityObsoleted();
+  bool IsUnavailable = Attr.getUnavailableLoc().isValid();
   StringRef Str;
   const StringLiteral *SE = 
     dyn_cast_or_null<const StringLiteral>(Attr.getMessageExpr());
   if (SE)
     Str = SE->getString();
-  
-  D->addAttr(::new (S.Context) AvailabilityAttr(Attr.getRange(), S.Context,
-                                                Platform,
-                                                Introduced.Version,
-                                                Deprecated.Version,
-                                                Obsoleted.Version,
-                                                IsUnavailable, 
-                                                Str));
+
+  mergeAvailabilityAttr(S, D, Attr.getRange(),
+                        Platform,
+                        Introduced.Version,
+                        Deprecated.Version,
+                        Obsoleted.Version,
+                        IsUnavailable,
+                        Str);
 }
 
 static void handleVisibilityAttr(Sema &S, Decl *D, const AttributeList &Attr) {