Implement C++11 [dcl.align]p1 and C11 6.7.5/2 rules for alignas and _Alignas.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173779 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 0e51ba3..01a3505 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -3272,9 +3272,47 @@
return;
}
- //FIXME: The C++0x version of this attribute has more limited applicabilty
- // than GNU's, and should error out when it is used to specify a
- // weaker alignment, rather than being silently ignored.
+ // C++11 alignas(...) and C11 _Alignas(...) have additional requirements.
+ // FIXME: Use a more reliable mechanism to determine how the attribute was
+ // spelled.
+ if (Attr.isKeywordAttribute()) {
+ // C++11 [dcl.align]p1:
+ // An alignment-specifier may be applied to a variable or to a class
+ // data member, but it shall not be applied to a bit-field, a function
+ // parameter, the formal parameter of a catch clause, or a variable
+ // declared with the register storage class specifier. An
+ // alignment-specifier may also be applied to the declaration of a class
+ // or enumeration type.
+ // C11 6.7.5/2:
+ // An alignment attribute shall not be specified in a declaration of
+ // a typedef, or a bit-field, or a function, or a parameter, or an
+ // object declared with the register storage-class specifier.
+ int DiagKind = -1;
+ if (isa<ParmVarDecl>(D)) {
+ DiagKind = 0;
+ } else if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
+ if (VD->getStorageClass() == SC_Register)
+ DiagKind = 1;
+ if (VD->isExceptionVariable())
+ DiagKind = 2;
+ } else if (FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
+ if (FD->isBitField())
+ DiagKind = 3;
+ } else if (!isa<TagDecl>(D)) {
+ S.Diag(Attr.getLoc(), diag::err_attribute_wrong_decl_type)
+ << Attr.getName() << ExpectedVariableFunctionOrTag;
+ return;
+ }
+ if (DiagKind != -1) {
+ S.Diag(Attr.getLoc(), diag::err_alignas_attribute_wrong_decl_type)
+ << Attr.getName() << DiagKind;
+ return;
+ }
+ }
+
+ // FIXME: The C++11 version of this attribute should error out when it is
+ // used to specify a weaker alignment, rather than being silently
+ // ignored.
if (Attr.getNumArgs() == 0) {
D->addAttr(::new (S.Context) AlignedAttr(Attr.getRange(), S.Context,