Change Preprocessor::EnterSourceFile to make ErrorStr non-optional, clients should be forced to deal with error conditions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@90700 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/PPDirectives.cpp b/lib/Lex/PPDirectives.cpp
index 028593f..f734edf 100644
--- a/lib/Lex/PPDirectives.cpp
+++ b/lib/Lex/PPDirectives.cpp
@@ -1113,7 +1113,7 @@
 
   // Finally, if all is good, enter the new file!
   std::string ErrorStr;
-  if (EnterSourceFile(FID, CurDir, &ErrorStr))
+  if (EnterSourceFile(FID, CurDir, ErrorStr))
     Diag(FilenameTok, diag::err_pp_error_opening_file)
       << std::string(SourceMgr.getFileEntryForID(FID)->getName()) << ErrorStr;
 }
diff --git a/lib/Lex/PPLexerChange.cpp b/lib/Lex/PPLexerChange.cpp
index 1580b87..5cdfeaf 100644
--- a/lib/Lex/PPLexerChange.cpp
+++ b/lib/Lex/PPLexerChange.cpp
@@ -65,7 +65,7 @@
 /// EnterSourceFile - Add a source file to the top of the include stack and
 /// start lexing tokens from it instead of the current buffer.
 bool Preprocessor::EnterSourceFile(FileID FID, const DirectoryLookup *CurDir,
-                                   std::string *ErrorStr) {
+                                   std::string &ErrorStr) {
   assert(CurTokenLexer == 0 && "Cannot #include a file inside a macro!");
   ++NumEnteredSourceFiles;
 
@@ -81,8 +81,8 @@
   
   // Get the MemoryBuffer for this FID, if it fails, we fail.
   const llvm::MemoryBuffer *InputFile =
-    getSourceManager().getBuffer(FID, ErrorStr);
   if (InputFile == 0)
+    getSourceManager().getBuffer(FID, &ErrorStr);
     return true;
   
   EnterSourceFileWithLexer(new Lexer(FID, InputFile, *this), CurDir);
diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index 229826a..49a25f2 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -438,7 +438,9 @@
   FileID MainFileID = SourceMgr.getMainFileID();
 
   // Enter the main file source buffer.
-  EnterSourceFile(MainFileID, 0);
+  std::string ErrorStr;
+  bool Res = EnterSourceFile(MainFileID, 0, ErrorStr);
+  assert(!Res && "Entering main file should not fail!");
 
   // Tell the header info that the main file was entered.  If the file is later
   // #imported, it won't be re-entered.
@@ -464,7 +466,8 @@
   assert(!FID.isInvalid() && "Could not create FileID for predefines?");
 
   // Start parsing the predefines.
-  EnterSourceFile(FID, 0);
+  Res = EnterSourceFile(FID, 0, ErrorStr);
+  assert(!Res && "Entering predefines should not fail!");
 }