[PATCH] Don't segfault in EmitCXXGlobalInitFunc when main file is a membuf

[Richard Smith]

================
Comment at: lib/CodeGen/CGDeclCXX.cpp:415
@@ +414,3 @@
+  SourceManager &SM = Context.getSourceManager();
+  if (SM.getFileEntryForID(SM.getMainFileID())) {
+    // Include the filename in the symbol name. Including "sub_" matches gcc and
----------------
  if (FileEntry *MainFile = SM.getFileEntryForID(SM.getMainFileID())) {

================
Comment at: lib/CodeGen/CGDeclCXX.cpp:420
@@ +419,3 @@
+    SmallString<128> FileName(llvm::sys::path::filename(
+        SM.getFileEntryForID(SM.getMainFileID())->getName()));
+    for (size_t i = 0; i < FileName.size(); ++i) {
----------------
  MainFile->getName()));

http://reviews.llvm.org/D5043