add a way to disable all builtins, wire it up to opt's -disable-simplifylibcalls flag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125978 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/TargetLibraryInfo.cpp

@@ -47,3 +47,9 @@ TargetLibraryInfo::TargetLibraryInfo(const Triple &T) : ImmutablePass(ID) {
   
   initialize(*this, T);
 }
+
+/// disableAllFunctions - This disables all builtins, which is used for options
+/// like -fno-builtin.
+void TargetLibraryInfo::disableAllFunctions() {
+  memset(AvailableArray, 0, sizeof(AvailableArray));
+}