1 files changed, 24 insertions, 0 deletions
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index dc99d4dabd4..6b840b9e475 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -1572,6 +1572,30 @@ bool ASTContext::isAlignmentRequired(QualType T) const {
   return isAlignmentRequired(T.getTypePtr());
 }
 
+unsigned ASTContext::getTypeAlignIfKnown(QualType T) const {
+  // An alignment on a typedef overrides anything else.
+  if (auto *TT = T->getAs<TypedefType>())
+    if (unsigned Align = TT->getDecl()->getMaxAlignment())
+      return Align;
+
+  // If we have an (array of) complete type, we're done.
+  T = getBaseElementType(T);
+  if (!T->isIncompleteType())
+    return getTypeAlign(T);
+
+  // If we had an array type, its element type might be a typedef
+  // type with an alignment attribute.
+  if (auto *TT = T->getAs<TypedefType>())
+    if (unsigned Align = TT->getDecl()->getMaxAlignment())
+      return Align;
+
+  // Otherwise, see if the declaration of the type had an attribute.
+  if (auto *TT = T->getAs<TagType>())
+    return TT->getDecl()->getMaxAlignment();
+
+  return 0;
+}
+
 TypeInfo ASTContext::getTypeInfo(const Type *T) const {
   TypeInfoMap::iterator I = MemoizedTypeInfo.find(T);
   if (I != MemoizedTypeInfo.end())