[PATCH] D43005: [ARM] Error out on .arm assembler directives on windows

[Gordon Keiser via Phabricator via llvm-commits]

codeman.consulting added a comment.

I can verify that if execution enters the kernel via trap or otherwise from a program in ARM mode on WinRT or Winphone 8.1 using the default MSVC compilers no ARM->Thumb2 switch occurs and the kernel's Thumb2 code executes in ARM mode, usually causing the system to black screen or hard lock with no dump / bugcheck.  The kernel doesn't make any attempt to change the mode on entry or exit.  It's been years since I did the research on that but I suspect it hasn't changed extensively and in any event makes the earlier devices flat out disastrous to execute ARM code on from a system perspective;  It //really// doesn't support the mode.

I haven't had the time to disassemble or a device to run Windows 10 IoT or similar yet.  Hopefully they've at least limited the crash to userland if it still occurs.


Repository:
  rL LLVM

https://reviews.llvm.org/D43005