Additional CMake flag handling improvements.

- Stop forcing AS/C/CXX/LINKER flags into the cache.
- Don't cache internal build system variables.
- Fix usages of PARENT_SCOPE rendered incorrect by previous
  patch.
- Fix usage of local variables within if() statements in macros;
  functions appear to allow for omission of ${} around vars in
  simple boolean checks. Macros apparently require ${} for all
  usages of if().

cmake/compiler_flags.cmake

@@ -22,7 +22,7 @@ macro (add_c_flag_if_supported c_flag)
     unset(C_FLAG_SUPPORTED CACHE)
     message("Checking C compiler flag support for: " ${c_flag})
     check_c_compiler_flag("${c_flag}" C_FLAG_SUPPORTED)
-    if (C_FLAG_SUPPORTED)
+    if (${C_FLAG_SUPPORTED})
       set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${c_flag}" CACHE STRING "")
     else ()
       set(DRACO_FAILED_C_FLAGS "${DRACO_FAILED_C_FLAGS} ${c_flag}" CACHE STRING
@@ -44,7 +44,7 @@ macro (add_cxx_flag_if_supported cxx_flag)
     unset(CXX_FLAG_SUPPORTED CACHE)
     message("Checking CXX compiler flag support for: " ${cxx_flag})
     check_cxx_compiler_flag("${cxx_flag}" CXX_FLAG_SUPPORTED)
-    if (CXX_FLAG_SUPPORTED)
+    if (${CXX_FLAG_SUPPORTED})
       set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${cxx_flag}" CACHE STRING "")
     else()
       set(DRACO_FAILED_CXX_FLAGS "${DRACO_FAILED_CXX_FLAGS} ${cxx_flag}" CACHE
@@ -70,12 +70,12 @@ macro (require_c_flag c_flag update_c_flags)
     unset(HAVE_C_FLAG CACHE)
     message("Checking C compiler flag support for: " ${c_flag})
     check_c_compiler_flag("${c_flag}" HAVE_C_FLAG)
-    if (NOT HAVE_C_FLAG)
+    if (NOT ${HAVE_C_FLAG})
       message(FATAL_ERROR
               "${PROJECT_NAME} requires support for C flag: ${c_flag}.")
     endif ()
-    if (update_c_flags)
+    if (${update_c_flags})
-      set(CMAKE_C_FLAGS "${c_flag} ${CMAKE_C_FLAGS}" CACHE STRING "")
+      set(CMAKE_C_FLAGS "${c_flag} ${CMAKE_C_FLAGS}")
     endif ()
   endif ()
 endmacro ()
@@ -90,12 +90,12 @@ macro (require_cxx_flag cxx_flag update_cxx_flags)
     unset(HAVE_CXX_FLAG CACHE)
     message("Checking CXX compiler flag support for: " ${cxx_flag})
     check_cxx_compiler_flag("${cxx_flag}" HAVE_CXX_FLAG)
-    if (NOT HAVE_CXX_FLAG)
+    if (NOT ${HAVE_CXX_FLAG})
       message(FATAL_ERROR
               "${PROJECT_NAME} requires support for CXX flag: ${cxx_flag}.")
     endif ()
-    if (update_cxx_flags)
+    if (${update_cxx_flags})
-      set(CMAKE_CXX_FLAGS "${cxx_flag} ${CMAKE_CXX_FLAGS}" CACHE STRING "")
+      set(CMAKE_CXX_FLAGS "${cxx_flag} ${CMAKE_CXX_FLAGS}")
     endif ()
   endif ()
 endmacro ()
@@ -138,7 +138,7 @@ macro (add_c_preproc_definition preproc_def)
   string(FIND "${CMAKE_C_FLAGS}" "${preproc_def}" PREPROC_DEF_FOUND)
 
   if (${PREPROC_DEF_FOUND} EQUAL -1)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D${preproc_def}" CACHE STRING "")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D${preproc_def}")
   endif ()
 endmacro ()
 
@@ -149,7 +149,7 @@ macro (add_cxx_preproc_definition preproc_def)
   string(FIND "${CMAKE_CXX_FLAGS}" "${preproc_def}" PREPROC_DEF_FOUND)
 
   if (${PREPROC_DEF_FOUND} EQUAL -1)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D${preproc_def}" CACHE STRING "")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D${preproc_def}")
   endif ()
 endmacro ()
 
@@ -166,7 +166,7 @@ macro (append_as_flag flag)
   string(FIND "${DRACO_AS_FLAGS}" "${flag}" AS_FLAG_FOUND)
 
   if (${AS_FLAG_FOUND} EQUAL -1)
-    set(DRACO_AS_FLAGS "${DRACO_AS_FLAGS} ${flag}" CACHE STRING "")
+    set(DRACO_AS_FLAGS "${DRACO_AS_FLAGS} ${flag}")
   endif ()
 endmacro ()
 
@@ -176,7 +176,7 @@ macro (append_c_flag flag)
   string(FIND "${CMAKE_C_FLAGS}" "${flag}" C_FLAG_FOUND)
 
   if (${C_FLAG_FOUND} EQUAL -1)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${flag}" CACHE STRING "")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${flag}")
   endif ()
 endmacro ()
 
@@ -186,7 +186,7 @@ macro (append_cxx_flag flag)
   string(FIND "${CMAKE_CXX_FLAGS}" "${flag}" CXX_FLAG_FOUND)
 
   if (${CXX_FLAG_FOUND} EQUAL -1)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${flag}" CACHE STRING "")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${flag}")
   endif ()
 endmacro ()
 
@@ -202,8 +202,7 @@ macro (append_exe_linker_flag flag)
   string(FIND "${CMAKE_EXE_LINKER_FLAGS}" "${flag}" LINKER_FLAG_FOUND)
 
   if (${LINKER_FLAG_FOUND} EQUAL -1)
-    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${flag}" CACHE STRING
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${flag}")
-        "")
   endif ()
 endmacro ()
 

cmake/compiler_tests.cmake

@@ -4,7 +4,7 @@ set(DRACO_CMAKE_COMPILER_TESTS_CMAKE_ 1)
 include(CheckCSourceCompiles)
 include(CheckCXXSourceCompiles)
 
-# The basic main() function used in all compile tests.
+# The basic main() macro used in all compile tests.
 set(DRACO_C_MAIN "\nint main(void) { return 0; }")
 set(DRACO_CXX_MAIN "\nint main() { return 0; }")
 
@@ -14,22 +14,22 @@ set(DRACO_C_FAILED_TESTS)
 set(DRACO_CXX_PASSED_TESTS)
 set(DRACO_CXX_FAILED_TESTS)
 
-function(draco_push_var var new_value)
+macro(draco_push_var var new_value)
-  set(SAVED_${var} ${var} PARENT_SCOPE)
+  set(SAVED_${var} ${var})
-  set(${var} ${new_value} PARENT_SCOPE)
+  set(${var} ${new_value})
-endfunction ()
+endmacro ()
 
-function(draco_pop_var var)
+macro(draco_pop_var var)
-  set(var ${SAVED_${var}} PARENT_SCOPE)
+  set(var ${SAVED_${var}})
-  unset(SAVED_${var} PARENT_SCOPE)
+  unset(SAVED_${var})
-endfunction ()
+endmacro ()
 
 # Confirms $test_source compiles and stores $test_name in one of
 # $DRACO_C_PASSED_TESTS or $DRACO_C_FAILED_TESTS depending on out come. When the
 # test passes $result_var is set to 1. When it fails $result_var is unset.
 # The test is not run if the test name is found in either of the passed or
 # failed test variables.
-function(draco_check_c_compiles test_name test_source result_var)
+macro(draco_check_c_compiles test_name test_source result_var)
   unset(C_TEST_PASSED CACHE)
   unset(C_TEST_FAILED CACHE)
   string(FIND "${DRACO_C_PASSED_TESTS}" "${test_name}" C_TEST_PASSED)
@@ -38,29 +38,27 @@ function(draco_check_c_compiles test_name test_source result_var)
     unset(C_TEST_COMPILED CACHE)
     message("Running C compiler test: ${test_name}")
     check_c_source_compiles("${test_source} ${DRACO_C_MAIN}" C_TEST_COMPILED)
-    set(${result_var} ${C_TEST_COMPILED} PARENT_SCOPE)
+    set(${result_var} ${C_TEST_COMPILED})
 
-    if (C_TEST_COMPILED)
+    if (${C_TEST_COMPILED})
-      set(DRACO_C_PASSED_TESTS "${DRACO_C_PASSED_TESTS} ${test_name}" CACHE
+      set(DRACO_C_PASSED_TESTS "${DRACO_C_PASSED_TESTS} ${test_name}")
-          STRING "" FORCE)
     else ()
-      set(DRACO_C_FAILED_TESTS "${DRACO_C_FAILED_TESTS} ${test_name}" CACHE
+      set(DRACO_C_FAILED_TESTS "${DRACO_C_FAILED_TESTS} ${test_name}")
-          STRING "" FORCE)
       message("C Compiler test ${test_name} failed.")
     endif ()
   elseif (NOT ${C_TEST_PASSED} EQUAL -1)
-    set(${result_var} 1 PARENT_SCOPE)
+    set(${result_var} 1)
   else ()  # ${C_TEST_FAILED} NOT EQUAL -1
-    unset(${result_var} PARENT_SCOPE)
+    unset(${result_var})
   endif ()
-endfunction ()
+endmacro ()
 
 # Confirms $test_source compiles and stores $test_name in one of
 # $DRACO_CXX_PASSED_TESTS or $DRACO_CXX_FAILED_TESTS depending on out come. When
 # the test passes $result_var is set to 1. When it fails $result_var is unset.
 # The test is not run if the test name is found in either of the passed or
 # failed test variables.
-function(draco_check_cxx_compiles test_name test_source result_var)
+macro(draco_check_cxx_compiles test_name test_source result_var)
   unset(CXX_TEST_PASSED CACHE)
   unset(CXX_TEST_FAILED CACHE)
   string(FIND "${DRACO_CXX_PASSED_TESTS}" "${test_name}" CXX_TEST_PASSED)
@@ -70,59 +68,57 @@ function(draco_check_cxx_compiles test_name test_source result_var)
     message("Running CXX compiler test: ${test_name}")
     check_cxx_source_compiles("${test_source} ${DRACO_CXX_MAIN}"
                               CXX_TEST_COMPILED)
-    set(${result_var} ${CXX_TEST_COMPILED} PARENT_SCOPE)
+    set(${result_var} ${CXX_TEST_COMPILED})
 
-    if (CXX_TEST_COMPILED)
+    if (${CXX_TEST_COMPILED})
-      set(DRACO_CXX_PASSED_TESTS "${DRACO_CXX_PASSED_TESTS} ${test_name}" CACHE
+      set(DRACO_CXX_PASSED_TESTS "${DRACO_CXX_PASSED_TESTS} ${test_name}")
-          STRING "" FORCE)
     else ()
-      set(DRACO_CXX_FAILED_TESTS "${DRACO_CXX_FAILED_TESTS} ${test_name}" CACHE
+      set(DRACO_CXX_FAILED_TESTS "${DRACO_CXX_FAILED_TESTS} ${test_name}")
-          STRING "" FORCE)
       message("CXX Compiler test ${test_name} failed.")
     endif ()
   elseif (NOT ${CXX_TEST_PASSED} EQUAL -1)
-    set(${result_var} 1 PARENT_SCOPE)
+    set(${result_var} 1)
   else ()  # ${CXX_TEST_FAILED} NOT EQUAL -1
-    unset(${result_var} PARENT_SCOPE)
+    unset(${result_var})
   endif ()
-endfunction ()
+endmacro ()
 
-# Convenience function that confirms $test_source compiles as C and C++.
+# Convenience macro that confirms $test_source compiles as C and C++.
 # $result_var is set to 1 when both tests are successful, and 0 when one or both
 # tests fail.
-# Note: This function is intended to be used to write to result variables that
+# Note: This macro is intended to be used to write to result variables that
 # are expanded via configure_file(). $result_var is set to 1 or 0 to allow
 # direct usage of the value in generated source files.
-function(draco_check_source_compiles test_name test_source result_var)
+macro(draco_check_source_compiles test_name test_source result_var)
   unset(C_PASSED)
   unset(CXX_PASSED)
   draco_check_c_compiles(${test_name} ${test_source} C_PASSED)
   draco_check_cxx_compiles(${test_name} ${test_source} CXX_PASSED)
-  if (C_PASSED AND CXX_PASSED)
+  if (${C_PASSED} AND ${CXX_PASSED})
-    set(${result_var} 1 PARENT_SCOPE)
+    set(${result_var} 1)
   else ()
-    set(${result_var} 0 PARENT_SCOPE)
+    set(${result_var} 0)
   endif ()
-endfunction ()
+endmacro ()
 
 # When inline support is detected for the current compiler the supported
 # inlining keyword is written to $result in caller scope.
-function (draco_get_inline result)
+macro (draco_get_inline result)
   draco_check_source_compiles("inline_check_1"
-                            "static inline void function(void) {}"
+                            "static inline void macro(void) {}"
                             HAVE_INLINE_1)
   if (HAVE_INLINE_1 EQUAL 1)
-    set(${result} "inline" PARENT_SCOPE)
+    set(${result} "inline")
     return()
   endif ()
 
   # Check __inline.
   draco_check_source_compiles("inline_check_2"
-                              "static __inline void function(void) {}"
+                              "static __inline void macro(void) {}"
                               HAVE_INLINE_2)
   if (HAVE_INLINE_2 EQUAL 1)
-    set(${result} "__inline" PARENT_SCOPE)
+    set(${result} "__inline")
   endif ()
-endfunction ()
+endmacro ()
 
 endif ()  # DRACO_CMAKE_COMPILER_TESTS_CMAKE_