cmake: Rework flags summary

CMakeLists.txt

@@ -334,34 +334,11 @@ endif()
 message("Cross compiling ....................... ${cross_status}")
 message("Valgrind .............................. ${SECP256K1_VALGRIND}")
 get_directory_property(definitions COMPILE_DEFINITIONS)
-string(REPLACE ";" " " definitions "${definitions}")
+list(JOIN definitions " " definitions)
 message("Preprocessor defined macros ........... ${definitions}")
 message("C compiler ............................ ${CMAKE_C_COMPILER_ID} ${CMAKE_C_COMPILER_VERSION}, ${CMAKE_C_COMPILER}")
-message("CFLAGS ................................ ${CMAKE_C_FLAGS}")
-get_directory_property(compile_options COMPILE_OPTIONS)
-string(REPLACE ";" " " compile_options "${compile_options}")
-message("Compile options ....................... " ${compile_options})
-if(NOT is_multi_config)
-  message("Build type:")
-  message(" - CMAKE_BUILD_TYPE ................... ${CMAKE_BUILD_TYPE}")
-  string(TOUPPER "${CMAKE_BUILD_TYPE}" build_type)
-  message(" - CFLAGS ............................. ${CMAKE_C_FLAGS_${build_type}}")
-  message(" - LDFLAGS for executables ............ ${CMAKE_EXE_LINKER_FLAGS_${build_type}}")
-  message(" - LDFLAGS for shared libraries ....... ${CMAKE_SHARED_LINKER_FLAGS_${build_type}}")
-else()
-  message("Supported configurations .............. ${CMAKE_CONFIGURATION_TYPES}")
-  message("RelWithDebInfo configuration:")
-  message(" - CFLAGS ............................. ${CMAKE_C_FLAGS_RELWITHDEBINFO}")
-  message(" - LDFLAGS for executables ............ ${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO}")
-  message(" - LDFLAGS for shared libraries ....... ${CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO}")
-  message("Debug configuration:")
-  message(" - CFLAGS ............................. ${CMAKE_C_FLAGS_DEBUG}")
-  message(" - LDFLAGS for executables ............ ${CMAKE_EXE_LINKER_FLAGS_DEBUG}")
-  message(" - LDFLAGS for shared libraries ....... ${CMAKE_SHARED_LINKER_FLAGS_DEBUG}")
-endif()
-if(SECP256K1_APPEND_CFLAGS)
-  message("SECP256K1_APPEND_CFLAGS ............... ${SECP256K1_APPEND_CFLAGS}")
-endif()
+include(FlagsSummary)
+flags_summary()
 message("")
 if(print_msan_notice)
   message(

cmake/FlagsSummary.cmake

@@ -0,0 +1,68 @@
+include_guard(GLOBAL)
+
+function(indent_message header content indent_num)
+  if(indent_num GREATER 0)
+    string(REPEAT " " ${indent_num} indentation)
+    string(REPEAT "." ${indent_num} tail)
+    string(REGEX REPLACE "${tail}$" "" header "${header}")
+  endif()
+  message("${indentation}${header} ${content}")
+endfunction()
+
+# Print tools' flags on best-effort. Include the abstracted
+# CMake flags that we touch ourselves.
+function(print_flags_per_config config indent_num)
+  string(TOUPPER "${config}" config_uppercase)
+
+  string(STRIP "${CMAKE_C_FLAGS} ${CMAKE_C_FLAGS_${config_uppercase}}" c_language_flags)
+  string(STRIP "${c_language_flags} ${CMAKE_C${CMAKE_C_STANDARD}_STANDARD_COMPILE_OPTION}" c_compiler_flags)
+  get_target_property(pic secp256k1 POSITION_INDEPENDENT_CODE)
+  if(pic AND CMAKE_C_COMPILE_OPTIONS_PIC)
+    string(APPEND c_compiler_flags " ${CMAKE_C_COMPILE_OPTIONS_PIC}")
+  endif()
+  if(CMAKE_C_COMPILE_OPTIONS_VISIBILITY AND CMAKE_C_VISIBILITY_PRESET)
+    string(APPEND c_compiler_flags " ${CMAKE_C_COMPILE_OPTIONS_VISIBILITY}${CMAKE_C_VISIBILITY_PRESET}")
+  endif()
+  get_directory_property(compile_options COMPILE_OPTIONS)
+  list(JOIN compile_options " " compile_options)
+  string(STRIP "${c_compiler_flags} ${compile_options}" c_compiler_flags)
+  string(STRIP "${c_compiler_flags} ${SECP256K1_APPEND_CFLAGS}" c_compiler_flags)
+  indent_message("C compiler flags ......................" "${c_compiler_flags}" ${indent_num})
+
+  if(BUILD_SHARED_LIBS)
+    string(STRIP "${c_language_flags} ${CMAKE_SHARED_LINKER_FLAGS}" linker_flags)
+    string(STRIP "${linker_flags} ${CMAKE_SHARED_LINKER_FLAGS_${config_uppercase}}" linker_flags)
+    indent_message("Linker flags .........................." "${linker_flags}" ${indent_num})
+  else()
+    string(STRIP "${CMAKE_STATIC_LINKER_FLAGS} ${CMAKE_STATIC_LINKER_FLAGS_${config_uppercase}}" archiver_options)
+    indent_message("Archiver options ......................" "${archiver_options}" ${indent_num})
+  endif()
+endfunction()
+
+function(flags_summary)
+  get_property(is_multi_config GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
+  if(is_multi_config)
+    list(JOIN CMAKE_CONFIGURATION_TYPES ", " configs)
+    message("Available build configurations ........ ${configs}")
+    if(CMAKE_GENERATOR MATCHES "Visual Studio")
+      set(default_config "Debug")
+    else()
+      list(GET CMAKE_CONFIGURATION_TYPES 0 default_config)
+    endif()
+    message("Default build configuration ........... ${default_config}")
+    foreach(config IN LISTS CMAKE_CONFIGURATION_TYPES)
+      message("")
+      message("'${config}' build configuration:")
+      print_flags_per_config(${config} 2)
+    endforeach()
+  else()
+    message("CMAKE_BUILD_TYPE ...................... ${CMAKE_BUILD_TYPE}")
+    print_flags_per_config(${CMAKE_BUILD_TYPE} 0)
+  endif()
+  message("")
+  message([=[
+NOTE: The summary above may not exactly match the final applied build flags
+      if any additional CMAKE_* or environment variables have been modified.
+      To see the exact flags applied, build with the --verbose option.
+]=])
+endfunction()