[gcc r12-2760] arm: ensure the arch_name is always set for the build target

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

https://gcc.gnu.org/g:62e66c6a6cc52dc0e014141d369cff52757cd7ae

commit r12-2760-g62e66c6a6cc52dc0e014141d369cff52757cd7ae
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.

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 6d781e23ee9..b2dd58d8751 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -3432,6 +3432,8 @@ 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;