Rearrange detection of changes in build flags

Move the code to detect flags changes to trigger a rebuild together,
allowing more accurate messages and adding new variables to the list of
variables to monitor for changes to trigger a rebuild.

diff --git a/Lib.mak b/Lib.mak
index 106c208fb5871121ecc9dbcbeeff5b76532320e3..db9b6a8bc98508c5ea948a75461a74780ed8cac7 100644 (file)
--- a/Lib.mak
+++ b/Lib.mak
@@ -166,19 +166,6 @@ override LDFLAGS += -pg --coverage
 endif
 
 
-# Automatic rebuilding when flags or commands changes
-######################################################
-
-# Re-compile C files if one of this variables changes
-COMPILE.c.FLAGS := $(CC) ~ $(CPPFLAGS) ~ $(CFLAGS) ~ $(TARGET_ARCH)
-
-# Re-compile C++ files if one of this variables changes
-COMPILE.cpp.FLAGS := $(CXX) ~ $(CPPFLAGS) ~ $(CXXFLAGS) ~ $(TARGET_ARCH)
-
-# Re-link binaries and libraries if one of this variables changes
-LINK.o.FLAGS := $(LD) ~ $(LDFLAGS) ~ $(TARGET_ARCH)
-
-
 # Automatic dependency handling
 ################################
 
@@ -221,19 +208,10 @@ all: $$(all)
 # Create build directory structure
 ###################################
 
-# Create a file with flags used to trigger rebuilding when they change. The
-# first argument is the name of the file where to store the flags, the second
-# are the flags and the third argument is a text to be displayed if the flags
-# have changed.  This should be used as a rule action or something where
-# a shell script is expected.
-gen_rebuild_flags = if test x"$2" != x"`cat $1 2>/dev/null`"; then \
-               test -f $1 && echo "$3"; \
-               echo "$2" > $1 ; fi
 
 # Create $O, $B, $L and $(INCLUDE_DIR) directories and replicate the directory
 # structure of the project into $O. Create one symlink "last" to the current
-# build directory.  It update the flags files to detect flag and/or compiler
-# changes to force a rebuild.
+# build directory.
 #
 # NOTE: the second mkdir can yield no arguments if the project don't have any
 #       subdirectories, that's why the current directory "." is included, so it
@@ -242,17 +220,42 @@ setup_build_dir__ := $(shell \
        mkdir -p $O $B $L $(INCLUDE_DIR); \
        mkdir -p . $(addprefix $O,$(patsubst $T%,%,\
                        $(shell find $T -type d -not -path '$D*'))); \
+       test -L $D/last || ln -s $F $D/last )
+
+
+# Automatic rebuilding when flags or commands changes
+######################################################
+
+# Re-compile C files if one of this variables changes
+COMPILE.c.FLAGS += $(CC) ~ $(CPPFLAGS) ~ $(CFLAGS) ~ $(TARGET_ARCH)
+
+# Re-compile C++ files if one of this variables changes
+COMPILE.cpp.FLAGS += $(CXX) ~ $(CPPFLAGS) ~ $(CXXFLAGS) ~ $(TARGET_ARCH)
+
+# Re-link binaries and libraries if one of this variables changes
+LINK.o.FLAGS += $(LD) ~ $(LDFLAGS) ~ $(TARGET_ARCH)
+
+# Create a file with flags used to trigger rebuilding when they change. The
+# first argument is the name of the file where to store the flags, the second
+# are the flags and the third argument is a text to be displayed if the flags
+# have changed.  This should be used as a rule action or something where
+# a shell script is expected.
+gen_rebuild_flags = if test x"$2" != x"`cat $1 2>/dev/null`"; then \
+               test -f $1 && echo "$3"; \
+               echo "$2" > $1 ; fi
+
+# Create files containing the current flags to trigger a rebuild if they change
+setup_flag_files__ := $(shell \
        $(call gen_rebuild_flags,$G/compile-c-flags, \
                        $(COMPILE.c.FLAGS),C compiler or flags;); \
        $(call gen_rebuild_flags,$G/compile-cpp-flags, \
                        $(COMPILE.cpp.FLAGS),C++ compiler or flags;); \
        $(call gen_rebuild_flags,$G/link-o-flags, \
-                       $(LINK.o.FLAGS),linker or link flags;); \
-       test -L $D/last || ln -s $F $D/last )
+                       $(LINK.o.FLAGS),linker or link flags;) )
 
 # Print any generated message (if verbose)
-$(if $V,$(if $(setup_build_dir__), \
-       $(info !! Something changed: $(setup_build_dir__) \
+$(if $V,$(if $(setup_flag_files__), \
+       $(info !! Something changed: $(setup_flag_files__) \
                        re-building affected files...)))
 
 endif