Implement new llc flag -disable-required-unwind-tables.

Corresponds to -fno-unwind-tables (usually default in gcc).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49361 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/TargetMachine.cpp

@@ -31,6 +31,7 @@ namespace llvm {
   bool UseSoftFloat;
   bool NoZerosInBSS;
   bool ExceptionHandling;
+  bool UnwindTablesOptional;
   Reloc::Model RelocationModel;
   CodeModel::Model CMModel;
   bool PerformTailCallOpt;
@@ -80,9 +81,14 @@ namespace {
               cl::init(false));
   cl::opt<bool, true>
   EnableExceptionHandling("enable-eh",
-               cl::desc("Exception handling should be emitted."),
+               cl::desc("Emit DWARF exception handling (default if target supports)"),
                cl::location(ExceptionHandling),
                cl::init(false));
+  cl::opt<bool, true>
+  DisableUnwindTables("disable-required-unwind-tables",
+               cl::desc("Do not require unwinding info for all functions"),
+               cl::location(UnwindTablesOptional),
+               cl::init(false));
 
   cl::opt<llvm::Reloc::Model, true>
   DefRelocationModel(