r176331 - In SourceManager::getFileIDLoaded(), add some sanity checks to make sure we don't enter an infinite loop.

[Argyrios Kyrtzidis]

Author: akirtzidis
Date: Thu Feb 28 21:26:00 2013
New Revision: 176331

URL: http://llvm.org/viewvc/llvm-project?rev=176331&view=rev
Log:
In SourceManager::getFileIDLoaded(), add some sanity checks to make sure we don't enter an infinite loop.

rdar://13120919

Modified:
    cfe/trunk/lib/Basic/SourceManager.cpp

Modified: cfe/trunk/lib/Basic/SourceManager.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/SourceManager.cpp?rev=176331&r1=176330&r2=176331&view=diff
==============================================================================
--- cfe/trunk/lib/Basic/SourceManager.cpp (original)
+++ cfe/trunk/lib/Basic/SourceManager.cpp Thu Feb 28 21:26:00 2013
@@ -840,10 +840,17 @@ FileID SourceManager::getFileIDLoaded(un
     ++NumProbes;
     unsigned MiddleIndex = (LessIndex - GreaterIndex) / 2 + GreaterIndex;
     const SrcMgr::SLocEntry &E = getLoadedSLocEntry(MiddleIndex);
+    if (E.getOffset() == 0)
+      return FileID(); // invalid entry.
 
     ++NumProbes;
 
     if (E.getOffset() > SLocOffset) {
+      // Sanity checking, otherwise a bug may lead to hanging in release build.
+      if (GreaterIndex == MiddleIndex) {
+        assert(0 && "binary search missed the entry");
+        return FileID();
+      }
       GreaterIndex = MiddleIndex;
       continue;
     }