fix a bug in SourceManager::getInstantiationLocSlowCase, where

we'd add an offset from the spelling location space to the 
instantiation location, which doesn't make sense and would
lead up to the text diagnostics crashing when presented with
non-sensical locations.

This fixes rdar://7597492, a crash on 255.vortex.

llvm-svn: 96004

1 files changed, 7 insertions, 3 deletions

diff --git a/clang/lib/Basic/SourceManager.cpp b/clang/lib/Basic/SourceManager.cpp
index 354bf7b..b91671a 100644
--- a/clang/lib/Basic/SourceManager.cpp
+++ b/clang/lib/Basic/SourceManager.cpp
@@ -560,10 +560,14 @@ FileID SourceManager::getFileIDSlow(unsigned SLocOffset) const {
 SourceLocation SourceManager::
 getInstantiationLocSlowCase(SourceLocation Loc) const {
   do {
-    std::pair<FileID, unsigned> LocInfo = getDecomposedLoc(Loc);
-    Loc = getSLocEntry(LocInfo.first).getInstantiation()
+    // Note: If Loc indicates an offset into a token that came from a macro
+    // expansion (e.g. the 5th character of the token) we do not want to add
+    // this offset when going to the instantiation location.  The instatiation
+    // location is the macro invocation, which the offset has nothing to do
+    // with.  This is unlike when we get the spelling loc, because the offset
+    // directly correspond to the token whose spelling we're inspecting.
+    Loc = getSLocEntry(getFileID(Loc)).getInstantiation()
                    .getInstantiationLocStart();
-    Loc = Loc.getFileLocWithOffset(LocInfo.second);
   } while (!Loc.isFileID());
 
   return Loc;