r266470 - in /trunk/libphobos/libdruntime/core:...

[ibuclaw@gcc.gnu.org]

Author: ibuclaw
Date: Mon Nov 26 17:27:34 2018
New Revision: 266470

URL: https://gcc.gnu.org/viewcvs?rev=266470&root=gcc&view=rev
Log:
libphobos: Fix backtraces in Fibers on AArch64.

When throwing an Exception in the Fiber the backtrace generation
crashes.  This happens because backtrace does not func the stack bottom.
Using '.cfi_undefined x30' tells the debug info that the value in the lr
is unknown, which seems to be the nicest way to stop the unwinder.
Setting x30 to 0 is another option, however it still creates one invalid
frame in gdb, so the .cfi variant is used here instead.

Backport from upstream druntime 2.083.

Reviewed-on: https://github.com/dlang/druntime/pull/2308

Modified:
    trunk/libphobos/libdruntime/core/thread.d
    trunk/libphobos/libdruntime/core/threadasm.S