[CodeGen] prevent abnormal on invalid attributes

Currently, when an invalid attribute is encountered on processing a .s file,
clang will abort due to llvm_unreachable.  Invalid user input should not cause
an abnormal termination of the compiler.  Change the interface to return a
boolean to indicate the failure as a first step towards improving hanlding of
malformed user input to clang.

Signed-off-by: Saleem Abdulrasool <compnerd@compnerd.org>
llvm-svn: 188047

1 files changed, 3 insertions, 1 deletions

diff --git a/llvm/lib/MC/MCNullStreamer.cpp b/llvm/lib/MC/MCNullStreamer.cpp
index 530c646..87a7db6 100644
--- a/llvm/lib/MC/MCNullStreamer.cpp
+++ b/llvm/lib/MC/MCNullStreamer.cpp
@@ -52,7 +52,9 @@ namespace {
                                           const MCSymbol *Label,
                                           unsigned PointerSize) {}
 
-    virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute){}
+    virtual bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute){
+      return true;
+    }
 
     virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}