[gcc r10-10054] arm: ensure the arch_name is always set for the build target

[Richard Earnshaw <rearnsha@gcc.gnu.org>]

https://gcc.gnu.org/g:a28ddcce5ce7b58a8edbb8c7b62efae981974f52

commit r10-10054-ga28ddcce5ce7b58a8edbb8c7b62efae981974f52
Author: Richard Earnshaw <rearnsha@arm.com>
Date:   Mon Jul 26 17:07:14 2021 +0100

    arm: ensure the arch_name is always set for the build target
    
    This should never happen now if GCC is invoked by the driver, but in
    the unusual case of calling cc1 (or its ilk) directly from the command
    line the build target's arch_name string can remain NULL.  This can
    complicate later processing meaning that we need to check for this
    case explicitly in some circumstances.  Nothing should rely on this
    behaviour, so it's simpler to always set the arch_name when
    configuring the build target and be done with it.
    
    gcc:
    
            * config/arm/arm.c (arm_configure_build_target): Ensure the target's
            arch_name is always set.
    
    (cherry picked from commit 62e66c6a6cc52dc0e014141d369cff52757cd7ae)

Diff:
---
 gcc/config/arm/arm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index ac06424df7e..24313962067 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -3427,6 +3427,8 @@ arm_configure_build_target (struct arm_build_target *target,
   const cpu_tune *tune_data = &all_tunes[arm_selected_tune - all_cores];
 
   /* Finish initializing the target structure.  */
+  if (!target->arch_name)
+    target->arch_name = arm_selected_arch->common.name;
   target->arch_pp_name = arm_selected_arch->arch;
   target->base_arch = arm_selected_arch->base_arch;
   target->profile = arm_selected_arch->profile;