Fix PR5633 by making the preprocessor handle the case where we can

stat a file but where mmaping it fails.  In this case, we emit an
error like:
t.c:1:10: fatal error: error opening file '../../foo.h'

instead of "cannot find file".

llvm-svn: 90110

1 files changed, 2 insertions, 1 deletions

diff --git a/clang/lib/Frontend/RewriteMacros.cpp b/clang/lib/Frontend/RewriteMacros.cpp
index b5d59c0aa40..0bcbd4ff0ee 100644
--- a/clang/lib/Frontend/RewriteMacros.cpp
+++ b/clang/lib/Frontend/RewriteMacros.cpp
@@ -65,7 +65,8 @@ static void LexRawTokensFromMainFile(Preprocessor &PP,
 
   // Create a lexer to lex all the tokens of the main file in raw mode.  Even
   // though it is in raw mode, it will not return comments.
-  Lexer RawLex(SM.getMainFileID(), SM, PP.getLangOptions());
+  const llvm::MemoryBuffer *FromFile = SM.getBuffer(SM.getMainFileID());
+  Lexer RawLex(SM.getMainFileID(), FromFile, SM, PP.getLangOptions());
 
   // Switch on comment lexing because we really do want them.
   RawLex.SetCommentRetentionState(true);