In http://gcc.gnu.org/ml/gcc/2005-10/msg00823.html, Jim Wilson wrote:
> The frame info is primarily used for C++ EH stack unwinding. Since you can't throw a C++ exception in an epilogue, epilogue frame info isn't needed > for this, and was never implemented for most targets. Which is a shame.
It can't be easily implemented in target-specific code alone. Sometimes there is code after the epilogue, so there would have to be
a mechanism to get the dwarf virtual machine back to the pre-epilogue state.
