Merge 'build: cmake: add "mode_list" target ' from Kefu Chai

scylla uses build modes like "debug" and "release" to differentiate
different build modes. while we intend to use the typical build
configurations / build types used by CMake like "Debug" and
"RelWithDebInfo" for naming CMAKE_CONFIGURATION_TYPES and
CMAKE_BUILD_TYPE. the former is used for naming the build directory and
for the preprocess macro named "SCYLLA_BUILD_MODE".

`test.py` and scylladb's CI are designed based on the naming of build
directory. in which, `test.py` lists the build modes using the dedicated
build target named `list_modes`, which is added by `configure.py`.

so, in this change, the target is added to CMake as well. the variables
of "scylla_build_mode" defined by the per-mode configuration are
collected and printed by the `list_modes`.

because, by default, CMake generates a target for each build
configuration when a multi-config generator is used. but we only want to
print the build mode for a single time when "list_modes" is built. so
a "BYPRODUCTS" is deliberately added for the target, and the patch of
this "BYPRODUCTS" is named without the "$<CONFIG>" it its path.

Closes scylladb/scylladb#16532

* github.com:scylladb/scylladb:
  build: cmake: add "mode_list" target
  build: cmake: define scylla_build_mode

CMakeLists.txt

@@ -28,9 +28,18 @@ include(mode.common)
 if(CMAKE_CONFIGURATION_TYPES)
     foreach(config ${CMAKE_CONFIGURATION_TYPES})
         include(mode.${config})
+        list(APPEND scylla_build_modes ${scylla_build_mode})
     endforeach()
+    add_custom_target(mode_list
+        COMMAND ${CMAKE_COMMAND} -E echo "$<JOIN:${scylla_build_modes}, >"
+        COMMENT "List configured modes"
+        BYPRODUCTS mode-list.phony.stamp
+        COMMAND_EXPAND_LISTS)
 else()
     include(mode.${CMAKE_BUILD_TYPE})
+    add_custom_target(mode_list
+        ${CMAKE_COMMAND} -E echo "${scylla_build_mode}"
+        COMMENT "List configured modes")
 endif()
 
 add_compile_definitions(

cmake/mode.Coverage.cmake

@@ -7,8 +7,9 @@ update_cxx_flags(CMAKE_CXX_FLAGS_COVERAGE
   WITH_DEBUG_INFO
   OPTIMIZATION_LEVEL "g")
 
+set(scylla_build_mode "coverage")
 set(Seastar_DEFINITIONS_COVERAGE
-  SCYLLA_BUILD_MODE=coverage
+  SCYLLA_BUILD_MODE=${scylla_build_mode}
   DEBUG
   SANITIZE
   DEBUG_LSA_SANITIZER

cmake/mode.Debug.cmake

@@ -9,8 +9,9 @@ update_cxx_flags(CMAKE_CXX_FLAGS_DEBUG
   WITH_DEBUG_INFO
   OPTIMIZATION_LEVEL ${OptimizationLevel})
 
+set(scylla_build_mode "debug")
 set(Seastar_DEFINITIONS_DEBUG
-  SCYLLA_BUILD_MODE=debug
+  SCYLLA_BUILD_MODE=${scylla_build_mode}
   DEBUG
   SANITIZE
   DEBUG_LSA_SANITIZER

cmake/mode.Dev.cmake

@@ -6,8 +6,9 @@ set(CMAKE_CXX_FLAGS_DEV
 update_cxx_flags(CMAKE_CXX_FLAGS_DEV
   OPTIMIZATION_LEVEL "2")
 
+set(scylla_build_mode "dev")
 set(Seastar_DEFINITIONS_DEV
-  SCYLLA_BUILD_MODE=dev
+  SCYLLA_BUILD_MODE=${scylla_build_mode}
   DEVEL
   SEASTAR_ENABLE_ALLOC_FAILURE_INJECTION
   SCYLLA_ENABLE_ERROR_INJECTION)

cmake/mode.RelWithDebInfo.cmake

@@ -7,8 +7,9 @@ update_cxx_flags(CMAKE_CXX_FLAGS_RELWITHDEBINFO
   WITH_DEBUG_INFO
   OPTIMIZATION_LEVEL "3")
 
+set(scylla_build_mode "release")
 add_compile_definitions(
-    $<$<CONFIG:RelWithDebInfo>:SCYLLA_BUILD_MODE=release>)
+    $<$<CONFIG:RelWithDebInfo>:SCYLLA_BUILD_MODE=${scylla_build_mode}>)
 
 if(CMAKE_SYSTEM_PROCESSOR MATCHES "arm64|aarch64")
   set(clang_inline_threshold 300)

cmake/mode.Sanitize.cmake

@@ -7,8 +7,9 @@ update_cxx_flags(CMAKE_CXX_FLAGS_SANITIZE
   WITH_DEBUG_INFO
   OPTIMIZATION_LEVEL "s")
 
+set(scylla_build_mode "sanitize")
 set(Seastar_DEFINITIONS_SANITIZE
-  SCYLLA_BUILD_MODE=sanitize
+  SCYLLA_BUILD_MODE=${scylla_build_mode}
   DEBUG
   SANITIZE
   DEBUG_LSA_SANITIZER