Add a firtool downloader (#157)

* Add a firtool downloader

The next version of Chisel will provide a native resolver for firtool.
We will remove the downloader after Chisel upgrades.

* CI: remove downloader for firtool

.github/workflows/main.yml

@@ -33,9 +33,6 @@ jobs:
             cp -r $GITHUB_WORKSPACE $GITHUB_WORKSPACE/../xs-env
             cd $GITHUB_WORKSPACE/../xs-env
             source ./env.sh
-            wget https://github.com/llvm/circt/releases/download/firtool-1.56.1/firrtl-bin-linux-x64.tar.gz
-            tar -xzf firrtl-bin-linux-x64.tar.gz
-            echo "FIRTOOL_BIN=$(pwd)/firtool-1.56.1/bin/firtool" >> $GITHUB_ENV
             cd $GITHUB_WORKSPACE/../xs-env/NutShell
             source ./env.sh
             make init
@@ -47,7 +44,7 @@ jobs:
             cd $GITHUB_WORKSPACE/../xs-env/NutShell
             source ./env.sh
             make clean
-            make verilog FIRTOOL=${FIRTOOL_BIN}
+            make verilog
 
       - name: Microbench - Nutshell
         run: |
@@ -56,7 +53,7 @@ jobs:
             cd $GITHUB_WORKSPACE/../xs-env/NutShell
             source ./env.sh
             make clean
-            make emu FIRTOOL=${FIRTOOL_BIN}
+            make emu
             ./build/emu -b 0 -e 0 -i ./ready-to-run/microbench.bin --diff ./ready-to-run/riscv64-nemu-interpreter-so
 
       - name: Linux - Nutshell
@@ -66,7 +63,7 @@ jobs:
             cd $GITHUB_WORKSPACE/../xs-env/NutShell
             source ./env.sh
             make clean
-            make emu FIRTOOL=${FIRTOOL_BIN}
+            make emu
             ./build/emu -b 0 -e 0 -i ./ready-to-run/linux.bin -C 200000000 --diff ./ready-to-run/riscv64-nemu-interpreter-so
 
       # - name: Microbench - Argo

Makefile

@@ -20,6 +20,22 @@ CORE  ?= inorder  # inorder  ooo  embedded
 MILL_ARGS = -td $(@D) BOARD=$(BOARD) CORE=$(CORE)
 FPGA_ARGS =
 
+# If firtool is not specified and not found in PATH, download and cache it.
+ifeq ($(FIRTOOL),)
+ifeq ($(shell which firtool 2>/dev/null),)
+FIRTOOL_VERSION = 1.61.0
+FIRTOOL_DIR = $(HOME)/.cache/firtool
+FIRTOOL_BIN = $(FIRTOOL_DIR)/firtool-$(FIRTOOL_VERSION)/bin/firtool
+ifeq ($(wildcard $(HOME)/.cache/firtool/firtool-$(FIRTOOL_VERSION)/bin),)
+$(info [INFO] Firtool not found.)
+FIRTOOL_URL = https://github.com/llvm/circt/releases/download/firtool-$(FIRTOOL_VERSION)/firrtl-bin-linux-x64.tar.gz
+$(info [INFO] Downloading from $(FIRTOOL_URL) to $(FIRTOOL_BIN))
+$(shell mkdir -p $(FIRTOOL_DIR) && curl -L $(FIRTOOL_URL) | tar -xzC $(FIRTOOL_DIR))
+endif
+FIRTOOL = $(FIRTOOL_BIN)
+endif
+endif
+
 ifneq ($(FIRTOOL),)
 MILL_ARGS += --firtool-binary-path $(FIRTOOL)
 endif