Re-introduce the ctor/dtor alias optimization, this time hidden behind a
command-line option which defaults off.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@96649 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index a193ac8..64a42bc 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -180,6 +180,8 @@
     Res.push_back("-mrelocation-model");
     Res.push_back(Opts.RelocationModel);
   }
+  if (Opts.CXXCtorDtorAliases)
+    Res.push_back("-mconstructor-aliases");
   if (!Opts.VerifyModule)
     Res.push_back("-disable-llvm-verifier");
 }
@@ -789,6 +791,7 @@
   Opts.SoftFloat = Args.hasArg(OPT_msoft_float);
   Opts.UnwindTables = Args.hasArg(OPT_munwind_tables);
   Opts.RelocationModel = getLastArgValue(Args, OPT_mrelocation_model, "pic");
+  Opts.CXXCtorDtorAliases = Args.hasArg(OPT_mconstructor_aliases);
 
   Opts.MainFileName = getLastArgValue(Args, OPT_main_file_name);
   Opts.VerifyModule = !Args.hasArg(OPT_disable_llvm_verifier);