[BE] Polish Makefile (#155425)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/155425
Approved by: https://github.com/ezyang

Makefile

@@ -1,59 +1,78 @@
 # This makefile does nothing but delegating the actual building to cmake.
-PYTHON = python3
-PIP = $(PYTHON) -m pip
+
+SHELL        = /bin/bash
+.SHELLFLAGS := -eu -o pipefail -c
+PYTHON      ?= $(shell command -v python3 || command -v python)
+PIP          = $(PYTHON) -m pip
 NIGHTLY_TOOL_OPTS := pull
 
+.PHONY: all
 all:
-	@mkdir -p build && cd build && cmake .. $(shell $(PYTHON) ./scripts/get_python_cmake_flags.py) && $(MAKE)
+	@cmake -S . -B build $(shell $(PYTHON) ./scripts/get_python_cmake_flags.py) && \
+		cmake --build build --parallel --
 
+.PHONY: local
 local:
 	@./scripts/build_local.sh
 
+.PHONY: android
 android:
 	@./scripts/build_android.sh
 
+.PHONY: ios
 ios:
 	@./scripts/build_ios.sh
 
-clean: # This will remove ALL build folders.
-	@rm -r build*/
+.PHONY: triton
+triton:
+	$(PIP) uninstall -y triton
+	@./scripts/install_triton_wheel.sh
 
+.PHONY: clean
+clean: # This will remove ALL build folders.
+	@rm -r build*/ || true
+
+.PHONY: linecount
 linecount:
 	@cloc --read-lang-def=caffe.cloc caffe2 || \
 		echo "Cloc is not available on the machine. You can install cloc with " && \
 		echo "    sudo apt-get install cloc"
 
+.PHONY: ensure-branch-clean
 ensure-branch-clean:
 	@if [ -n "$(shell git status --porcelain)" ]; then \
 		echo "Please commit or stash all changes before running this script"; \
 		exit 1; \
 	fi
 
+.PHONY: setup-env
 setup-env: ensure-branch-clean
 	$(PYTHON) tools/nightly.py $(NIGHTLY_TOOL_OPTS)
 
+.PHONY: setup-env-cuda
 setup-env-cuda:
 	$(MAKE) setup-env PYTHON="$(PYTHON)" NIGHTLY_TOOL_OPTS="$(NIGHTLY_TOOL_OPTS) --cuda"
 
+.PHONY: setup-env-rocm
 setup-env-rocm:
 	$(MAKE) setup-env PYTHON="$(PYTHON)" NIGHTLY_TOOL_OPTS="$(NIGHTLY_TOOL_OPTS) --rocm"
 
-setup_env: setup-env
-setup_env_cuda: setup-env-cuda
-setup_env_rocm: setup-env-rocm
-
+.PHONY: setup-lint
 setup-lint:
 	$(PIP) install lintrunner
 	lintrunner init
 
-setup_lint: setup-lint
-
+.PHONY: lint
 lint:
 	lintrunner
 
+.PHONY: quicklint
 quicklint:
 	lintrunner
 
-triton:
-	$(PIP) uninstall -y triton
-	@./scripts/install_triton_wheel.sh
+# Deprecated target aliases
+.PHONY: setup_env setup_env_cuda setup_env_rocm setup_lint
+setup_env: setup-env
+setup_env_cuda: setup-env-cuda
+setup_env_rocm: setup-env-rocm
+setup_lint: setup-lint