From 845dc0000f66e306b81d6b7b9342cd523de080bc Mon Sep 17 00:00:00 2001
From: Risheng1128 <hi4u29ck02@gmail.com>
Date: Sat, 22 Oct 2022 23:05:26 +0800
Subject: [PATCH] Detect toolchain automatically

Detect toolchain automatically by creating toolchain list,
and check the items in list is installed or not.

If there are multiple toolchain installed, get the first
item in valid toolchain list.
---
 mk/toolchain.mk | 32 ++++++++++++++------------------
 1 file changed, 14 insertions(+), 18 deletions(-)

diff --git a/mk/toolchain.mk b/mk/toolchain.mk
index 61812c631..e39e8f6b4 100644
--- a/mk/toolchain.mk
+++ b/mk/toolchain.mk
@@ -9,24 +9,20 @@ else
 endif
 
 # Validate GNU Toolchain for RISC-V
-CROSS_COMPILE ?= riscv32-unknown-elf-
-RV32_CC = $(CROSS_COMPILE)gcc
-RV32_CC := $(shell which $(RV32_CC))
-ifndef RV32_CC
-    # xPack GNU RISC-V Embedded GCC
-    CROSS_COMPILE = riscv-none-elf-
-    RV32_CC = $(CROSS_COMPILE)gcc
-    RV32_CC := $(shell which $(RV32_CC))
-    ifndef RV32_CC
-        # DEPRECATED: Replaced by xpack-dev-tools/riscv-none-elf-gcc-xpack
-        CROSS_COMPILE = riscv-none-embed-
-        RV32_CC = $(CROSS_COMPILE)gcc
-        RV32_CC := $(shell which $(RV32_CC))
-        ifndef RV32_CC
-        $(warning No GNU Toolchain for RISC-V found.)
-        CROSS_COMPILE :=
-        endif
-    endif
+TOOLCHAIN_LIST := riscv-none-elf-      \
+		  riscv32-unknown-elf- \
+		  riscv64-unknown-elf- \
+		  riscv-none-embed-
+
+# TODO: add support to clang/llvm based cross compilers
+VALID_TOOLCHAIN := $(foreach toolchain,$(TOOLCHAIN_LIST),     \
+		   $(shell which $(toolchain)gcc > /dev/null) \
+		   $(if $(filter 0,$(.SHELLSTATUS)),$(toolchain)))
+
+# Get the first element in valid toolchain list
+CROSS_COMPILE = $(word 1,$(VALID_TOOLCHAIN))
+ifeq ($(CROSS_COMPILE),)
+$(error GNU Toolchain for RISC-V is required. Please check package installation)
 endif
 
 export CROSS_COMPILE