make the verbose raw-lexer ctor fully explicit instead of having
embedded magic.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@62417 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index 704c4db..c5b36fc 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -124,15 +124,9 @@
 /// suitable for calls to 'LexRawToken'.  This lexer assumes that the text
 /// range will outlive it, so it doesn't take ownership of it.
 Lexer::Lexer(SourceLocation fileloc, const LangOptions &features,
-             const char *BufPtr, const char *BufEnd,
-             const llvm::MemoryBuffer *FromFile)
+             const char *BufStart, const char *BufPtr, const char *BufEnd)
   : FileLoc(fileloc), Features(features) {
 
-  // If a MemoryBuffer was specified, use its start as BufferStart. This affects
-  // the source location objects produced by this lexer.
-  const char *BufStart = BufPtr;
-  if (FromFile) BufStart = FromFile->getBufferStart();
-
   InitLexer(BufStart, BufPtr, BufEnd);
   
   // We *are* in raw mode.
@@ -197,7 +191,7 @@
   // all obviously single-char tokens.  This could use 
   // Lexer::isObviouslySimpleCharacter for example to handle identifiers or
   // something.
-  const char *BufEnd = SM.getBufferData(Loc).second;
+  std::pair<const char *,const char *> Buffer = SM.getBufferData(Loc);
   
   // Create a langops struct and enable trigraphs.  This is sufficient for
   // measuring tokens.
@@ -205,7 +199,7 @@
   LangOpts.Trigraphs = true;
   
   // Create a lexer starting at the beginning of this token.
-  Lexer TheLexer(Loc, LangOpts, StrData, BufEnd);
+  Lexer TheLexer(Loc, LangOpts, Buffer.first, StrData, Buffer.second);
   Token TheTok;
   TheLexer.LexFromRawLexer(TheTok);
   return TheTok.getLength();