Fixed a crasher where we were accessing a symbol with a bad index.

llvm-svn: 133377
diff --git a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
index e788bd0..2169dbc 100644
--- a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
+++ b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
@@ -968,7 +968,7 @@
                                 // using nlist_idx in case we ever start trimming entries out
                                 if (symbol_name[0] == '/')
                                     N_SO_index = sym_idx;
-                                else if (minimize && (N_SO_index == sym_idx - 1))
+                                else if (minimize && (N_SO_index == sym_idx - 1) && ((sym_idx - 1) < num_syms))
                                 {
                                     const char *so_path = sym[sym_idx - 1].GetMangled().GetDemangledName().AsCString();
                                     if (so_path && so_path[0])