Implement [dcl.align]p5 and C11 6.7.5/4: alignas cannot underalign.

Also support alignas(0), which C++11 and C11 require us to ignore.

llvm-svn: 174157

1 files changed, 14 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 834041c65c0..4404c6f9a0e 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -4611,6 +4611,9 @@ Sema::ActOnVariableDeclarator(Scope *S, Declarator &D, DeclContext *DC,
   // Handle attributes prior to checking for duplicates in MergeVarDecl
   ProcessDeclAttributes(S, NewVD, D);
 
+  if (NewVD->hasAttrs())
+    CheckAlignasUnderalignment(NewVD);
+
   if (getLangOpts().CUDA) {
     // CUDA B.2.5: "__shared__ and __constant__ variables have implied static
     // storage [duration]."
@@ -10158,10 +10161,14 @@ FieldDecl *Sema::CheckFieldDecl(DeclarationName Name, QualType T,
 
   // FIXME: We need to pass in the attributes given an AST
   // representation, not a parser representation.
-  if (D)
+  if (D) {
     // FIXME: What to pass instead of TUScope?
     ProcessDeclAttributes(TUScope, NewFD, *D);
 
+    if (NewFD->hasAttrs())
+      CheckAlignasUnderalignment(NewFD);
+  }
+
   // In auto-retain/release, infer strong retension for fields of
   // retainable type.
   if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(NewFD))
@@ -10680,6 +10687,8 @@ void Sema::ActOnFields(Scope* S,
     if (!Completed)
       Record->completeDefinition();
 
+    if (Record->hasAttrs())
+      CheckAlignasUnderalignment(Record);
   } else {
     ObjCIvarDecl **ClsFields =
       reinterpret_cast<ObjCIvarDecl**>(RecFields.data());
@@ -11427,6 +11436,10 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceLocation LBraceLoc,
     DeclsInPrototypeScope.push_back(Enum);
 
   CheckForDuplicateEnumValues(*this, Elements, NumElements, Enum, EnumType);
+
+  // Now that the enum type is defined, ensure it's not been underaligned.
+  if (Enum->hasAttrs())
+    CheckAlignasUnderalignment(Enum);
 }
 
 Decl *Sema::ActOnFileScopeAsmDecl(Expr *expr,