[ms-inline asm] Add comments.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@162396 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaStmtAsm.cpp b/lib/Sema/SemaStmtAsm.cpp
index 0827e3d..ac22f13 100644
--- a/lib/Sema/SemaStmtAsm.cpp
+++ b/lib/Sema/SemaStmtAsm.cpp
@@ -398,7 +398,9 @@
     buildMSAsmPieces(AsmStrings[i], Pieces[i]);
-// Build the unmodified MSAsmString.
+// Build the unmodified AsmString used by the IR.  Also build the individual
+// asm instruction(s) and place them in the AsmStrings vector; these are fed
+// to the AsmParser.
 static std::string buildMSAsmString(Sema &SemaRef, ArrayRef<Token> AsmToks,
                                     std::vector<std::string> &AsmStrings,
                      std::vector<std::pair<unsigned,unsigned> > &AsmTokRanges) {