.debug_frame not generated by ARC gas

[Vineet Gupta]

Hi,

ARC Linux has an in-kernel dwarf unwinder which has historically consumed
.debug_frame. The kernel is built with -gdwarf-2 and -fasynchronous-unwind-tables
toggles which until recently used to generate both .debug_frame and .eh_frame -
latter being discarded by the kernel linker script.

With a recent ARC gas change to support asm cfi psuedo-ops - dwarf info is now
generated by gas and NOT gcc. But more importantly, we no longer get .debug_frame
with above 2 toggles. If we drop -fasynchronous-unwind-tables then .debug_frame is
generated.

So here are the questions:
1. Is it OK to drop -fasynchronous-unwind-tables toggle and still assume that
"precise" unwind info will be generated (as mentioned in gnu documentation)
2. If not, how do we coax gas to generate .debug_frame even in presence of
-fasynchronous-unwind-tables

Thx,
-Vineet