Finish semantic analysis for [[carries_dependency]] attribute.

This required plumbing through a new flag to determine whether a ParmVarDecl is
actually a parameter of a function declaration (as opposed to a function
typedef etc, where the attribute is prohibited). Weirdly, this attribute (just
like [[noreturn]]) cannot be applied to a function type, just to a function
declaration (and its parameters).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173726 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 38 insertions, 4 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index fb63953de9..e8d14e6bef 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1911,6 +1911,9 @@ static void checkNewAttributesAfterDef(Sema &S, Decl *New, const Decl *Old) {
 /// mergeDeclAttributes - Copy attributes from the Old decl to the New one.
 void Sema::mergeDeclAttributes(NamedDecl *New, Decl *Old,
                                AvailabilityMergeKind AMK) {
+  if (!Old->hasAttrs() && !New->hasAttrs())
+    return;
+
   // attributes declared post-definition are currently ignored
   checkNewAttributesAfterDef(*this, New, Old);
 
@@ -1956,7 +1959,25 @@ void Sema::mergeDeclAttributes(NamedDecl *New, Decl *Old,
 /// to the new one.
 static void mergeParamDeclAttributes(ParmVarDecl *newDecl,
                                      const ParmVarDecl *oldDecl,
-                                     ASTContext &C) {
+                                     Sema &S) {
+  // C++11 [dcl.attr.depend]p2:
+  //   The first declaration of a function shall specify the
+  //   carries_dependency attribute for its declarator-id if any declaration
+  //   of the function specifies the carries_dependency attribute.
+  if (newDecl->hasAttr<CarriesDependencyAttr>() &&
+      !oldDecl->hasAttr<CarriesDependencyAttr>()) {
+    S.Diag(newDecl->getAttr<CarriesDependencyAttr>()->getLocation(),
+           diag::err_carries_dependency_missing_on_first_decl) << 1/*Param*/;
+    // Find the first declaration of the parameter.
+    // FIXME: Should we build redeclaration chains for function parameters?
+    const FunctionDecl *FirstFD =
+      cast<FunctionDecl>(oldDecl->getDeclContext())->getFirstDeclaration();
+    const ParmVarDecl *FirstVD =
+      FirstFD->getParamDecl(oldDecl->getFunctionScopeIndex());
+    S.Diag(FirstVD->getLocation(),
+           diag::note_carries_dependency_missing_first_decl) << 1/*Param*/;
+  }
+
   if (!oldDecl->hasAttrs())
     return;
 
@@ -1970,7 +1991,8 @@ static void mergeParamDeclAttributes(ParmVarDecl *newDecl,
        i = oldDecl->specific_attr_begin<InheritableParamAttr>(),
        e = oldDecl->specific_attr_end<InheritableParamAttr>(); i != e; ++i) {
     if (!DeclHasAttr(newDecl, *i)) {
-      InheritableAttr *newAttr = cast<InheritableParamAttr>((*i)->clone(C));
+      InheritableAttr *newAttr =
+        cast<InheritableParamAttr>((*i)->clone(S.Context));
       newAttr->setInherited(true);
       newDecl->addAttr(newAttr);
       foundAny = true;
@@ -2295,6 +2317,18 @@ bool Sema::MergeFunctionDecl(FunctionDecl *New, Decl *OldD, Scope *S) {
            diag::note_noreturn_missing_first_decl);
     }
 
+    // C++11 [dcl.attr.depend]p2:
+    //   The first declaration of a function shall specify the
+    //   carries_dependency attribute for its declarator-id if any declaration
+    //   of the function specifies the carries_dependency attribute.
+    if (New->hasAttr<CarriesDependencyAttr>() &&
+        !Old->hasAttr<CarriesDependencyAttr>()) {
+      Diag(New->getAttr<CarriesDependencyAttr>()->getLocation(),
+           diag::err_carries_dependency_missing_on_first_decl) << 0/*Function*/;
+      Diag(Old->getFirstDeclaration()->getLocation(),
+           diag::note_carries_dependency_missing_first_decl) << 0/*Function*/;
+    }
+
     // (C++98 8.3.5p3):
     //   All declarations for a function shall agree exactly in both the
     //   return type and the parameter-type-list.
@@ -2487,7 +2521,7 @@ bool Sema::MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old,
   if (New->getNumParams() == Old->getNumParams())
     for (unsigned i = 0, e = New->getNumParams(); i != e; ++i)
       mergeParamDeclAttributes(New->getParamDecl(i), Old->getParamDecl(i),
-                               Context);
+                               *this);
 
   if (getLangOpts().CPlusPlus)
     return MergeCXXFunctionDecl(New, Old, S);
@@ -2514,7 +2548,7 @@ void Sema::mergeObjCMethodDecls(ObjCMethodDecl *newMethod,
   for (ObjCMethodDecl::param_iterator
          ni = newMethod->param_begin(), ne = newMethod->param_end();
        ni != ne && oi != oe; ++ni, ++oi)
-    mergeParamDeclAttributes(*ni, *oi, Context);
+    mergeParamDeclAttributes(*ni, *oi, *this);
 
   CheckObjCMethodOverride(newMethod, oldMethod);
 }