From 55e223353af615bb0f8ed4d17a8032b8f09f6883 Mon Sep 17 00:00:00 2001
From: Marian Buschsieweke <marian.buschsieweke@posteo.net>
Date: Mon, 3 Jul 2023 15:20:30 +0200
Subject: [PATCH] makefiles/arch/riscv.inc.mk: speed up toolchain detection

- Use a sane (a.k.a. simply expanded) variable for the `$(TARGET_ARCH)`
  instead of an insane (a.k.a. recursive expended) variable
    - The toolchain detection will now happen only once, rather than
      each and every time `$(TARGET_ARCH)` is referenced
- Use a single call to `which` rather than one per possible target
  triple

Fixes https://github.com/RIOT-OS/RIOT/issues/19788
---
 makefiles/arch/riscv.inc.mk | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/makefiles/arch/riscv.inc.mk b/makefiles/arch/riscv.inc.mk
index 3544b214b1..b8fc8da19a 100644
--- a/makefiles/arch/riscv.inc.mk
+++ b/makefiles/arch/riscv.inc.mk
@@ -35,10 +35,15 @@ TARGET_ARCH_RISCV ?= \
     $(subst -gcc,,\
       $(notdir \
         $(word 1,\
-          $(foreach triple,$(_TRIPLES_TO_TEST),$(shell which $(triple)-gcc 2> /dev/null))))))
+          $(shell which $(addsuffix -gcc,$(_TRIPLES_TO_TEST)) 2> /dev/null)))))
 
 TARGET_ARCH ?= $(TARGET_ARCH_RISCV)
 
+# Convert to a simply expanded variable here, as a recursively expended
+# variable would result in detecting the toolchain each and every time again the
+# toolchain is referenced.
+TARGET_ARCH := $(TARGET_ARCH)
+
 ifeq (,$(TARGET_ARCH))
   $(error No RISC-V toolchain detected. Make sure a RISC-V toolchain is installed.)
 endif