add a new "getPreferredTypeAlign" method to return the preferred alignment
of a type. The implementation is currently something of a hack, but is
sufficient for now and allows clients to be built on it.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63108 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 2662860..e7c08e2 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -453,6 +453,22 @@
return std::make_pair(Width, Align);
}
+/// getPreferredTypeAlign - Return the "preferred" alignment of the specified
+/// type for the current target in bits. This can be different than the ABI
+/// alignment in cases where it is beneficial for performance to overalign
+/// a data type.
+unsigned ASTContext::getPreferredTypeAlign(const Type *T) {
+ unsigned ABIAlign = getTypeAlign(T);
+
+ // Doubles should be naturally aligned if possible.
+ if (const BuiltinType *BT = dyn_cast<BuiltinType>(getCanonicalType(T)))
+ if (BT->getKind() == BuiltinType::Double)
+ return std::max(ABIAlign, 8U);
+
+ return ABIAlign;
+}
+
+
/// LayoutField - Field layout.
void ASTRecordLayout::LayoutField(const FieldDecl *FD, unsigned FieldNo,
bool IsUnion, unsigned StructPacking,