Fix colored cmake output when using Ninja (#7444)

Summary:
Compilers usually color output by default if they detect the output is a terminal, but this breaks if you are using Ninja. Adding an option to let users explicitly control it, and setting it automatically when Ninja is used.

Pull Request resolved: #7444

Reviewed By: kgpai

Differential Revision: D51056403

Pulled By: pedroerp

fbshipit-source-id: cf40e58b23823ac7e9682ae3b412c43ccbd71aee

CMakeLists.txt

@@ -13,7 +13,7 @@
 # limitations under the License.
 cmake_minimum_required(VERSION 3.14)
 
-# the policy allows us to change options without caching
+# The policy allows us to change options without caching.
 cmake_policy(SET CMP0077 NEW)
 set(CMAKE_POLICY_DEFAULT_CMP0077 NEW)
 
@@ -25,7 +25,7 @@ if(POLICY CMP0135)
   set(CMAKE_POLICY_DEFAULT_CMP0135 NEW)
 endif()
 
-# set the project name
+# Set the project name.
 project(velox)
 
 # If we are in an active conda env disable search in system paths and add env to
@@ -62,6 +62,7 @@ option(
   VELOX_BUILD_MINIMAL
   "Build a minimal set of components only. This will override other build options."
   OFF)
+
 # option() always creates a BOOL variable so we have to use a normal cache
 # variable with STRING type for this option.
 #
@@ -106,6 +107,12 @@ option(
   "make buildPartitionBounds_ a vector int64 instead of int32 to avoid integer overflow when the hashtable has billions of records"
   OFF)
 
+# Explicitly force compilers to generate colored output. Compilers usually do
+# this by default if they detect the output is a terminal, but this assumption
+# is broken if you use ninja.
+option(VELOX_FORCE_COLORED_OUTPUT
+       "Always produce ANSI-colored output (GNU/Clang only)." OFF)
+
 if(${VELOX_BUILD_MINIMAL})
   # Enable and disable components for velox base build
   set(VELOX_BUILD_TESTING OFF)
@@ -194,6 +201,15 @@ if(VELOX_ENABLE_CCACHE
   endif()
 endif()
 
+if(${VELOX_FORCE_COLORED_OUTPUT})
+  if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+    add_compile_options(-fdiagnostics-color=always)
+  elseif("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang"
+         OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
+    add_compile_options(-fcolor-diagnostics)
+  endif()
+endif()
+
 # At the moment we prefer static linking but by default cmake looks for shared
 # libs first. This will still fallback to shared libs when static ones are not
 # found

Makefile

@@ -54,7 +54,12 @@ endif
 USE_NINJA ?= 1
 ifeq ($(USE_NINJA), 1)
 ifneq ($(shell which ninja), )
-GENERATOR=-GNinja -DMAX_LINK_JOBS=$(MAX_LINK_JOBS) -DMAX_HIGH_MEM_JOBS=$(MAX_HIGH_MEM_JOBS)
+GENERATOR := -GNinja
+GENERATOR += -DMAX_LINK_JOBS=$(MAX_LINK_JOBS)
+GENERATOR += -DMAX_HIGH_MEM_JOBS=$(MAX_HIGH_MEM_JOBS)
+
+# Ninja makes compilers disable colored output by default.
+GENERATOR += -DVELOX_FORCE_COLORED_OUTPUT=ON
 endif
 endif
 
@@ -84,7 +89,6 @@ cmake:					#: Use CMake to create a Makefile build system
 		${CMAKE_FLAGS} \
 		$(GENERATOR) \
 		$(USE_CCACHE) \
-		$(FORCE_COLOR) \
 		${EXTRA_CMAKE_FLAGS}
 
 cmake-gpu: