platforms/shodan/riscv_toolchain.mk - build - Git at Google

 # Copyright 2022 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #     https://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.

 TOOLCHAIN_SRC_DIR   := $(OUT)/tmp/toolchain/riscv-gnu-toolchain
 TOOLCHAIN_BUILD_DIR := $(OUT)/tmp/toolchain/build_toolchain
 TOOLCHAIN_OUT_DIR   := $(CACHE)/toolchain
 TOOLCHAIN_BIN       := $(TOOLCHAIN_OUT_DIR)/bin/riscv32-unknown-elf-gdb

 TOOLCHAINIREE_SRC_DIR   := $(OUT)/tmp/toolchain/riscv-gnu-toolchain_iree
 TOOLCHAINIREE_BUILD_DIR  := $(OUT)/tmp/toolchain/build_toolchain_iree
 TOOLCHAINIREE_OUT_DIR    := $(CACHE)/toolchain_iree_rv32imf
 TOOLCHAINIREE_BIN        := $(TOOLCHAINIREE_OUT_DIR)/bin/riscv32-unknown-elf-gdb
 TOOLCHAINLLVM_SRC_DIR    := $(OUT)/tmp/toolchain/llvm-project
 TOOLCHAINLLVM_BUILD_DIR  := $(OUT)/tmp/toolchain/build_toolchain_llvm
 TOOLCHAINLLVM_BIN        := $(TOOLCHAINIREE_OUT_DIR)/bin/clang

 TOOLCHAIN_KELVIN_SRC_DIR := $(OUT)/tmp/toolchain/riscv-gnu-toolchain_kelvin
 TOOLCHAIN_KELVIN_BUILD_DIR := $(OUT)/tmp/toolchain/build_toolchain_kelvin
 TOOLCHAIN_KELVIN_OUT_DIR := $(CACHE)/toolchain_kelvin
 TOOLCHAIN_KELVIN_BIN       := $(TOOLCHAIN_KELVIN_OUT_DIR)/bin/riscv32-unknown-elf-gdb

 TOOLCHAIN_BUILD_DATE := $(shell date +%Y-%m-%d)


 toolchain_src:
 	if [[ -f "${TOOLCHAIN_BIN}" ]]; then \
 		echo "Toolchain exists, run 'm toolchain_clean' if you really want to rebuild"; \
 	else \
 		$(ROOTDIR)/scripts/download-toolchain.sh $(TOOLCHAIN_SRC_DIR); \
 	fi

 $(TOOLCHAIN_BUILD_DIR):
 	mkdir -p $(TOOLCHAIN_BUILD_DIR)

 # Note the make is purposely launched with high job counts, so we can build it
 # faster with a powerful machine (e.g. CI).
 $(TOOLCHAIN_BIN): | toolchain_src $(TOOLCHAIN_BUILD_DIR)
 	cd $(TOOLCHAIN_BUILD_DIR) && $(TOOLCHAIN_SRC_DIR)/configure \
 		--srcdir=$(TOOLCHAIN_SRC_DIR) \
 		--prefix=$(TOOLCHAIN_OUT_DIR) \
 		--with-arch=rv32imac \
 		--with-abi=ilp32
 	$(MAKE) -C $(TOOLCHAIN_BUILD_DIR) newlib \
 	  GDB_TARGET_FLAGS="--with-expat=yes --with-python=python3.11"
 	$(MAKE) -C $(TOOLCHAIN_BUILD_DIR) clean

 $(OUT)/toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz: $(TOOLCHAIN_BIN)
 	tar -C $(CACHE) -czf \
 		"$(OUT)/toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz" toolchain
 	cd $(OUT) && sha256sum "toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz" > \
 		"toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz.sha256sum"
 	@echo "==========================================================="
 	@echo "Toolchain tarball ready at $(OUT)/toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz"
 	@echo "==========================================================="

 ## Builds the GCC toolchain for the security core and SMC.
 #
 # Note: this actually builds from source, rather than fetching a release
 # tarball, and is most likely not the target you actually want.
 #
 # This target can take hours to build, and results in a tarball and sha256sum
 # called `out/toolchain_<timestamp>.tar.gz` and
 # `out/toolchain_<timestamp>.tar.gz.sha256sum`, ready for
 # upload. In the process of generating this tarball, this target also builds the
 # actual tools in `cache/toolchain`, so untarring this tarball is
 # unneccessary.
 toolchain: $(OUT)/toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz

 ## Cleans up the toolchain from the cache directory
 #
 # Generally not needed to be run unless something has changed or broken in the
 # caching mechanisms built into the build system.
 toolchain_clean:
 	rm -rf "$(TOOLCHAIN_OUT_DIR)" "$(TOOLCHAIN_SRC_DIR)" "$(TOOLCHAIN_BUILD_DIR)"

 toolchain_src_llvm:
 	if [[ -f "${TOOLCHAINLLVM_BIN}" ]]; then \
 		echo "Toolchain for LLVM exists, run 'm toolchain_llvm_clean' if you really want to rebuild"; \
 	else \
 		$(ROOTDIR)/scripts/download-toolchain.sh $(TOOLCHAINIREE_SRC_DIR) "LLVM"; \
 	fi

 # IREE toolchain
 $(TOOLCHAINIREE_BUILD_DIR):
 	mkdir -p $(TOOLCHAINIREE_BUILD_DIR)

 # Note the make is purposely launched with high job counts, so we can build it
 # faster with a powerful machine (e.g. CI).
 $(TOOLCHAINIREE_BIN): | toolchain_src_llvm $(TOOLCHAINIREE_BUILD_DIR)
 	cd $(TOOLCHAINIREE_BUILD_DIR) && $(TOOLCHAINIREE_SRC_DIR)/configure \
 		--srcdir=$(TOOLCHAINIREE_SRC_DIR) \
 		--prefix=$(TOOLCHAINIREE_OUT_DIR) \
 		--with-arch=rv32i2p0mf2p0 \
 		--with-abi=ilp32 \
 		--with-cmodel=medany
 	$(MAKE) -C $(TOOLCHAINIREE_BUILD_DIR) newlib \
 	  GDB_TARGET_FLAGS="--with-expat=yes --with-python=python3.11"
 	$(MAKE) -C $(TOOLCHAINIREE_BUILD_DIR) clean

 # Build with 32-bit baremetal config.
 $(TOOLCHAINLLVM_BIN): $(TOOLCHAINIREE_BIN)
 	cmake -B $(TOOLCHAINLLVM_BUILD_DIR) \
 		-DCMAKE_INSTALL_PREFIX=$(TOOLCHAINIREE_OUT_DIR) \
 		-DCMAKE_C_COMPILER=clang  -DCMAKE_CXX_COMPILER=clang++ \
 		-DCMAKE_BUILD_TYPE=Release \
 		-DLLVM_TARGETS_TO_BUILD="RISCV" \
 		-DLLVM_ENABLE_PROJECTS="clang;lld"  \
 		-DLLVM_DEFAULT_TARGET_TRIPLE="riscv32-unknown-elf" \
 		-DLLVM_INSTALL_TOOLCHAIN_ONLY=On \
 		-DDEFAULT_SYSROOT=../riscv32-unknown-elf \
 		-G Ninja \
 		$(TOOLCHAINLLVM_SRC_DIR)/llvm
 	cmake --build $(TOOLCHAINLLVM_BUILD_DIR) --target install
 	cmake --build $(TOOLCHAINLLVM_BUILD_DIR) --target clean
 # Prepare a newlib-nano directory for the default link of -lc, -lgloss, etc.
 	mkdir -p "$(TOOLCHAINIREE_OUT_DIR)/riscv32-unknown-elf/lib/newlib-nano"
 	cd "$(TOOLCHAINIREE_OUT_DIR)/riscv32-unknown-elf/lib/newlib-nano" && ln -sf ../libc_nano.a libc.a
 	cd "$(TOOLCHAINIREE_OUT_DIR)/riscv32-unknown-elf/lib/newlib-nano" && ln -sf ../libg_nano.a libg.a
 	cd "$(TOOLCHAINIREE_OUT_DIR)/riscv32-unknown-elf/lib/newlib-nano" && ln -sf ../libm_nano.a libm.a
 	cd "$(TOOLCHAINIREE_OUT_DIR)/riscv32-unknown-elf/lib/newlib-nano" && ln -sf ../libgloss_nano.a libgloss.a

 $(OUT)/toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz: $(TOOLCHAINLLVM_BIN)
 	tar -C $(CACHE) -czf \
 		"$(OUT)/toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz" toolchain_iree_rv32imf
 	cd $(OUT) && sha256sum "toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz" > \
 		"toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz.sha256sum"
 	@echo "==========================================================="
 	@echo "Toolchain tarball ready at $(OUT)/toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz"
 	@echo "==========================================================="

 ## Builds the LLVM toolchain for the vector core.
 #
 # Note: this actually builds from source, rather than fetching a release
 # tarball, and is most likely not the target you actually want.
 #
 # This target can take hours to build, and results in a tarball and sha256sum
 # called `out/toolchain_iree_rv32_<timestamp>.tar.gz` and
 # `out/toolchain_iree_rv32_<timestamp>.tar.gz.sha256sum`, ready for upload.
 # In the process of generating this tarball, this target also builds the actual
 # tools in `cache/toolchain_iree_rv32imf`, so untarring this tarball is
 # unneccessary.
 toolchain_llvm: $(OUT)/toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz

 ## Removes the IREE RV32IMF toolchain from cache/, forcing a re-fetch if needed.
 toolchain_llvm_clean:
 	rm -rf $(TOOLCHAINIREE_OUT_DIR) $(OUT)/tmp/toolchain


 toolchain_kelvin_src:
 	if [[ -f "${TOOLCHAIN_KELVIN_BIN}" ]]; then \
 		echo "Toolchain exists, run 'm toolchain_kelvin_clean' if you really want to rebuild"; \
 	else \
 		"$(ROOTDIR)/scripts/download-toolchain.sh" "$(TOOLCHAIN_KELVIN_SRC_DIR)" KELVIN; \
 	fi

 $(TOOLCHAIN_KELVIN_BUILD_DIR):
 	mkdir -p $(TOOLCHAIN_KELVIN_BUILD_DIR)

 # Note it does not support python GDB, for we can't support CentOS7 (EDACloud)
 # properly.
 # Also pin the i ISA version to 2.1
 $(TOOLCHAIN_KELVIN_BIN): | toolchain_kelvin_src $(TOOLCHAIN_KELVIN_BUILD_DIR)
 	cd $(TOOLCHAIN_KELVIN_BUILD_DIR) && $(TOOLCHAIN_KELVIN_SRC_DIR)/configure \
 		--srcdir=$(TOOLCHAIN_KELVIN_SRC_DIR) \
 		--prefix=$(TOOLCHAIN_KELVIN_OUT_DIR) \
 		--with-arch=rv32i2p1m_zicsr_zifencei_zbb \
 		--with-abi=ilp32
 # binutil_2.40 has special doc targets for gas/doc/asconfig.texi. Need to patch the
 # configured Makefile.
 	./scripts/update-toolchain-makefile.sh "$(TOOLCHAIN_KELVIN_BUILD_DIR)/Makefile"
 	$(MAKE) -C $(TOOLCHAIN_KELVIN_BUILD_DIR)
 	$(MAKE) -C $(TOOLCHAIN_KELVIN_BUILD_DIR) clean

 $(OUT)/toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz: $(TOOLCHAIN_KELVIN_BIN)
 	tar -C $(CACHE) -czf \
 		"$(OUT)/toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz" toolchain_kelvin
 	cd $(OUT) && sha256sum "toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz" > \
 		"toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz.sha256sum"
 	@echo "==========================================================="
 	@echo "Kelvin Toolchain tarball ready at $(OUT)/toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz"
 	@echo "==========================================================="

 ## Builds Kelvin GCC toolchain.
 #
 # Note: this actually builds from source, rather than fetching a release
 # tarball, and is most likely not the target you actually want.
 #
 # This target can take hours to build, and results in a tarball and sha256sum
 # called `out/toolchain_kelvin_<timestamp>.tar.gz` and
 # `out/toolchain_kelvin_<timestamp>.tar.gz.sha256sum`, ready for
 # upload. In the process of generating this tarball, this target also builds the
 # actual tools in `cache/toolchain_kelvin`, so untarring this tarball is
 # unneccessary.
 toolchain_kelvin: $(OUT)/toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz

 ## Removes the Kelvin toolchain from cache/, forcing a re-fetch if needed.
 toolchain_kelvin_clean:
 	rm -rf "$(TOOLCHAIN_KELVIN_OUT_DIR)" "$(TOOLCHAIN_KELVIN_SRC_DIR)" "$(TOOLCHAIN_KELVIN_BUILD_DIR)"

 .PHONY:: toolchain toolchain_src toolchain_clean
 .PHONY:: toolchain_llvm toolchain_src_llvm toolchain_llvm_clean
 .PHONY:: toolchain_kelvin toolchain_kelvin_src toolchain_kelvin_clean
	# Copyright 2022 Google LLC
	#
	# Licensed under the Apache License, Version 2.0 (the "License");
	# you may not use this file except in compliance with the License.
	# You may obtain a copy of the License at
	#
	# https://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.

	TOOLCHAIN_SRC_DIR := $(OUT)/tmp/toolchain/riscv-gnu-toolchain
	TOOLCHAIN_BUILD_DIR := $(OUT)/tmp/toolchain/build_toolchain
	TOOLCHAIN_OUT_DIR := $(CACHE)/toolchain
	TOOLCHAIN_BIN := $(TOOLCHAIN_OUT_DIR)/bin/riscv32-unknown-elf-gdb

	TOOLCHAINIREE_SRC_DIR := $(OUT)/tmp/toolchain/riscv-gnu-toolchain_iree
	TOOLCHAINIREE_BUILD_DIR := $(OUT)/tmp/toolchain/build_toolchain_iree
	TOOLCHAINIREE_OUT_DIR := $(CACHE)/toolchain_iree_rv32imf
	TOOLCHAINIREE_BIN := $(TOOLCHAINIREE_OUT_DIR)/bin/riscv32-unknown-elf-gdb
	TOOLCHAINLLVM_SRC_DIR := $(OUT)/tmp/toolchain/llvm-project
	TOOLCHAINLLVM_BUILD_DIR := $(OUT)/tmp/toolchain/build_toolchain_llvm
	TOOLCHAINLLVM_BIN := $(TOOLCHAINIREE_OUT_DIR)/bin/clang

	TOOLCHAIN_KELVIN_SRC_DIR := $(OUT)/tmp/toolchain/riscv-gnu-toolchain_kelvin
	TOOLCHAIN_KELVIN_BUILD_DIR := $(OUT)/tmp/toolchain/build_toolchain_kelvin
	TOOLCHAIN_KELVIN_OUT_DIR := $(CACHE)/toolchain_kelvin
	TOOLCHAIN_KELVIN_BIN := $(TOOLCHAIN_KELVIN_OUT_DIR)/bin/riscv32-unknown-elf-gdb

	TOOLCHAIN_BUILD_DATE := $(shell date +%Y-%m-%d)


	toolchain_src:
	if [[ -f "${TOOLCHAIN_BIN}" ]]; then \
	echo "Toolchain exists, run 'm toolchain_clean' if you really want to rebuild"; \
	else \
	$(ROOTDIR)/scripts/download-toolchain.sh $(TOOLCHAIN_SRC_DIR); \
	fi

	$(TOOLCHAIN_BUILD_DIR):
	mkdir -p $(TOOLCHAIN_BUILD_DIR)

	# Note the make is purposely launched with high job counts, so we can build it
	# faster with a powerful machine (e.g. CI).
	$(TOOLCHAIN_BIN): \| toolchain_src $(TOOLCHAIN_BUILD_DIR)
	cd $(TOOLCHAIN_BUILD_DIR) && $(TOOLCHAIN_SRC_DIR)/configure \
	--srcdir=$(TOOLCHAIN_SRC_DIR) \
	--prefix=$(TOOLCHAIN_OUT_DIR) \
	--with-arch=rv32imac \
	--with-abi=ilp32
	$(MAKE) -C $(TOOLCHAIN_BUILD_DIR) newlib \
	GDB_TARGET_FLAGS="--with-expat=yes --with-python=python3.11"
	$(MAKE) -C $(TOOLCHAIN_BUILD_DIR) clean

	$(OUT)/toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz: $(TOOLCHAIN_BIN)
	tar -C $(CACHE) -czf \
	"$(OUT)/toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz" toolchain
	cd $(OUT) && sha256sum "toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz" > \
	"toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz.sha256sum"
	@echo "==========================================================="
	@echo "Toolchain tarball ready at $(OUT)/toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz"
	@echo "==========================================================="

	## Builds the GCC toolchain for the security core and SMC.
	#
	# Note: this actually builds from source, rather than fetching a release
	# tarball, and is most likely not the target you actually want.
	#
	# This target can take hours to build, and results in a tarball and sha256sum
	# called `out/toolchain_<timestamp>.tar.gz` and
	# `out/toolchain_<timestamp>.tar.gz.sha256sum`, ready for
	# upload. In the process of generating this tarball, this target also builds the
	# actual tools in `cache/toolchain`, so untarring this tarball is
	# unneccessary.
	toolchain: $(OUT)/toolchain_$(TOOLCHAIN_BUILD_DATE).tar.gz

	## Cleans up the toolchain from the cache directory
	#
	# Generally not needed to be run unless something has changed or broken in the
	# caching mechanisms built into the build system.
	toolchain_clean:
	rm -rf "$(TOOLCHAIN_OUT_DIR)" "$(TOOLCHAIN_SRC_DIR)" "$(TOOLCHAIN_BUILD_DIR)"

	toolchain_src_llvm:
	if [[ -f "${TOOLCHAINLLVM_BIN}" ]]; then \
	echo "Toolchain for LLVM exists, run 'm toolchain_llvm_clean' if you really want to rebuild"; \
	else \
	$(ROOTDIR)/scripts/download-toolchain.sh $(TOOLCHAINIREE_SRC_DIR) "LLVM"; \
	fi

	# IREE toolchain
	$(TOOLCHAINIREE_BUILD_DIR):
	mkdir -p $(TOOLCHAINIREE_BUILD_DIR)

	# Note the make is purposely launched with high job counts, so we can build it
	# faster with a powerful machine (e.g. CI).
	$(TOOLCHAINIREE_BIN): \| toolchain_src_llvm $(TOOLCHAINIREE_BUILD_DIR)
	cd $(TOOLCHAINIREE_BUILD_DIR) && $(TOOLCHAINIREE_SRC_DIR)/configure \
	--srcdir=$(TOOLCHAINIREE_SRC_DIR) \
	--prefix=$(TOOLCHAINIREE_OUT_DIR) \
	--with-arch=rv32i2p0mf2p0 \
	--with-abi=ilp32 \
	--with-cmodel=medany
	$(MAKE) -C $(TOOLCHAINIREE_BUILD_DIR) newlib \
	GDB_TARGET_FLAGS="--with-expat=yes --with-python=python3.11"
	$(MAKE) -C $(TOOLCHAINIREE_BUILD_DIR) clean

	# Build with 32-bit baremetal config.
	$(TOOLCHAINLLVM_BIN): $(TOOLCHAINIREE_BIN)
	cmake -B $(TOOLCHAINLLVM_BUILD_DIR) \
	-DCMAKE_INSTALL_PREFIX=$(TOOLCHAINIREE_OUT_DIR) \
	-DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ \
	-DCMAKE_BUILD_TYPE=Release \
	-DLLVM_TARGETS_TO_BUILD="RISCV" \
	-DLLVM_ENABLE_PROJECTS="clang;lld" \
	-DLLVM_DEFAULT_TARGET_TRIPLE="riscv32-unknown-elf" \
	-DLLVM_INSTALL_TOOLCHAIN_ONLY=On \
	-DDEFAULT_SYSROOT=../riscv32-unknown-elf \
	-G Ninja \
	$(TOOLCHAINLLVM_SRC_DIR)/llvm
	cmake --build $(TOOLCHAINLLVM_BUILD_DIR) --target install
	cmake --build $(TOOLCHAINLLVM_BUILD_DIR) --target clean
	# Prepare a newlib-nano directory for the default link of -lc, -lgloss, etc.
	mkdir -p "$(TOOLCHAINIREE_OUT_DIR)/riscv32-unknown-elf/lib/newlib-nano"
	cd "$(TOOLCHAINIREE_OUT_DIR)/riscv32-unknown-elf/lib/newlib-nano" && ln -sf ../libc_nano.a libc.a
	cd "$(TOOLCHAINIREE_OUT_DIR)/riscv32-unknown-elf/lib/newlib-nano" && ln -sf ../libg_nano.a libg.a
	cd "$(TOOLCHAINIREE_OUT_DIR)/riscv32-unknown-elf/lib/newlib-nano" && ln -sf ../libm_nano.a libm.a
	cd "$(TOOLCHAINIREE_OUT_DIR)/riscv32-unknown-elf/lib/newlib-nano" && ln -sf ../libgloss_nano.a libgloss.a

	$(OUT)/toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz: $(TOOLCHAINLLVM_BIN)
	tar -C $(CACHE) -czf \
	"$(OUT)/toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz" toolchain_iree_rv32imf
	cd $(OUT) && sha256sum "toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz" > \
	"toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz.sha256sum"
	@echo "==========================================================="
	@echo "Toolchain tarball ready at $(OUT)/toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz"
	@echo "==========================================================="

	## Builds the LLVM toolchain for the vector core.
	#
	# Note: this actually builds from source, rather than fetching a release
	# tarball, and is most likely not the target you actually want.
	#
	# This target can take hours to build, and results in a tarball and sha256sum
	# called `out/toolchain_iree_rv32_<timestamp>.tar.gz` and
	# `out/toolchain_iree_rv32_<timestamp>.tar.gz.sha256sum`, ready for upload.
	# In the process of generating this tarball, this target also builds the actual
	# tools in `cache/toolchain_iree_rv32imf`, so untarring this tarball is
	# unneccessary.
	toolchain_llvm: $(OUT)/toolchain_iree_rv32_$(TOOLCHAIN_BUILD_DATE).tar.gz

	## Removes the IREE RV32IMF toolchain from cache/, forcing a re-fetch if needed.
	toolchain_llvm_clean:
	rm -rf $(TOOLCHAINIREE_OUT_DIR) $(OUT)/tmp/toolchain


	toolchain_kelvin_src:
	if [[ -f "${TOOLCHAIN_KELVIN_BIN}" ]]; then \
	echo "Toolchain exists, run 'm toolchain_kelvin_clean' if you really want to rebuild"; \
	else \
	"$(ROOTDIR)/scripts/download-toolchain.sh" "$(TOOLCHAIN_KELVIN_SRC_DIR)" KELVIN; \
	fi

	$(TOOLCHAIN_KELVIN_BUILD_DIR):
	mkdir -p $(TOOLCHAIN_KELVIN_BUILD_DIR)

	# Note it does not support python GDB, for we can't support CentOS7 (EDACloud)
	# properly.
	# Also pin the i ISA version to 2.1
	$(TOOLCHAIN_KELVIN_BIN): \| toolchain_kelvin_src $(TOOLCHAIN_KELVIN_BUILD_DIR)
	cd $(TOOLCHAIN_KELVIN_BUILD_DIR) && $(TOOLCHAIN_KELVIN_SRC_DIR)/configure \
	--srcdir=$(TOOLCHAIN_KELVIN_SRC_DIR) \
	--prefix=$(TOOLCHAIN_KELVIN_OUT_DIR) \
	--with-arch=rv32i2p1m_zicsr_zifencei_zbb \
	--with-abi=ilp32
	# binutil_2.40 has special doc targets for gas/doc/asconfig.texi. Need to patch the
	# configured Makefile.
	./scripts/update-toolchain-makefile.sh "$(TOOLCHAIN_KELVIN_BUILD_DIR)/Makefile"
	$(MAKE) -C $(TOOLCHAIN_KELVIN_BUILD_DIR)
	$(MAKE) -C $(TOOLCHAIN_KELVIN_BUILD_DIR) clean

	$(OUT)/toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz: $(TOOLCHAIN_KELVIN_BIN)
	tar -C $(CACHE) -czf \
	"$(OUT)/toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz" toolchain_kelvin
	cd $(OUT) && sha256sum "toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz" > \
	"toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz.sha256sum"
	@echo "==========================================================="
	@echo "Kelvin Toolchain tarball ready at $(OUT)/toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz"
	@echo "==========================================================="

	## Builds Kelvin GCC toolchain.
	#
	# Note: this actually builds from source, rather than fetching a release
	# tarball, and is most likely not the target you actually want.
	#
	# This target can take hours to build, and results in a tarball and sha256sum
	# called `out/toolchain_kelvin_<timestamp>.tar.gz` and
	# `out/toolchain_kelvin_<timestamp>.tar.gz.sha256sum`, ready for
	# upload. In the process of generating this tarball, this target also builds the
	# actual tools in `cache/toolchain_kelvin`, so untarring this tarball is
	# unneccessary.
	toolchain_kelvin: $(OUT)/toolchain_kelvin_$(TOOLCHAIN_BUILD_DATE).tar.gz

	## Removes the Kelvin toolchain from cache/, forcing a re-fetch if needed.
	toolchain_kelvin_clean:
	rm -rf "$(TOOLCHAIN_KELVIN_OUT_DIR)" "$(TOOLCHAIN_KELVIN_SRC_DIR)" "$(TOOLCHAIN_KELVIN_BUILD_DIR)"

	.PHONY:: toolchain toolchain_src toolchain_clean
	.PHONY:: toolchain_llvm toolchain_src_llvm toolchain_llvm_clean
	.PHONY:: toolchain_kelvin toolchain_kelvin_src toolchain_kelvin_clean