[pdb] Change type visitor pattern to be dynamic.

This allows better catching of compiler errors since we can use
the override keyword to verify that methods are actually
overridden.

Also in this patch I've changed from storing a boolean Error
code everywhere to returning an llvm::Error, to propagate richer
error information up the call stack.

Reviewed By: ruiu, rnk
Differential Revision: http://reviews.llvm.org/D21410

llvm-svn: 272926

1 files changed, 2 insertions, 0 deletions

diff --git a/llvm/lib/DebugInfo/PDB/Raw/RawError.cpp b/llvm/lib/DebugInfo/PDB/Raw/RawError.cpp
index 07aebb7d739..eb169f70e11 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/RawError.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/RawError.cpp
@@ -32,6 +32,8 @@ public:
       return "The specified block address is not valid.";
     case raw_error_code::not_writable:
       return "The PDB does not support writing.";
+    case raw_error_code::invalid_tpi_hash:
+      return "The Type record has an invalid hash value.";
     }
     llvm_unreachable("Unrecognized raw_error_code");
   }