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

1 files changed, 8 insertions, 2 deletions

diff --git a/include/clang/AST/ASTContext.h b/include/clang/AST/ASTContext.h
index 684feb2402..a01199d4b2 100644
--- a/include/clang/AST/ASTContext.h
+++ b/include/clang/AST/ASTContext.h
@@ -394,8 +394,8 @@ public:
     return getTypeInfo(T).first;
   }
   
-  /// getTypeAlign - Return the alignment of the specified type, in bits.  This
-  /// method does not work on incomplete types.
+  /// getTypeAlign - Return the ABI-specified alignment of a type, in bits.
+  /// This method does not work on incomplete types.
   unsigned getTypeAlign(QualType T) {
     return getTypeInfo(T).second;
   }
@@ -403,6 +403,12 @@ public:
     return getTypeInfo(T).second;
   }
   
+  /// 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 getPreferredTypeAlign(const Type *T);
+  
   /// getDeclAlign - Return the alignment of the specified decl that should be
   /// returned by __alignof().  Note that bitfields do not have a valid
   /// alignment, so this method will assert on them.