Change the way in which the CML2 configuration is handled to separate it out from the build.

SConstruct

@@ -22,54 +22,110 @@ import os
 includeDirectory = 'include'
 toolsDirectory = 'tools'
 cml2ToolsDirectory = toolsDirectory + '/cml2-tools'
-
 buildDirectory = 'build'
 
-environment = Environment ( )
+cml2CompileRulesFile = buildDirectory + '/cml2Rules.out'
+cml2ConfigPropertiesFile = buildDirectory + '/cml2Config.out'
+cml2ConfigHeaderFile = buildDirectory + '/cml2Config.h'
 
-configuration = Configure ( environment , config_h = 'config.h' )
-environment = configuration.Finish ( )
+#  The choice of which parts of the kernel to compile and include in the build depends on the configuration
+#  which is managed using CML2.  CML2 uses a base configuration file (currently #configs/arm.cml) to drive
+#  an interaction with the user which results in a trio of files that specify the user choice.
+#
+#  cml2RulesFile is the pickled version of the source configuration driver.
+#
+#  cml2Config.out is a properties type representation of the user selected configuration data.
+#
+#  cml2Config.h is a C include file representation of the user selected configuration data derived from
+#  cml2Config.out, it is essential for the compilation of the C code of the kernel and the tasks.
+#
+#  Since the DAG for building the kernel relies on the information from the configuration split the build
+#  into two distinct phases as Autotools and Waf do, configure then build.  Achieve this by partitioning the
+#  SCons DAG building in two depending on the command line.
 
-arch = 'arm'
-platform = 'pb926'
+if 'configure' in COMMAND_LINE_TARGETS  :
 
-linkerScript = includeDirectory + '/l4/arch/' + arch + '/mylinks.lds'
+    def performCML2Configuration ( target , source , env ) :
+        if not os.path.isdir ( buildDirectory ) : os.mkdir ( buildDirectory )
+        os.system ( cml2ToolsDirectory + '/cmlcompile.py -o ' + cml2CompileRulesFile + ' ' + source[0].path )
+        os.system ( cml2ToolsDirectory +  '/cmlconfigure.py -c -o ' + cml2ConfigPropertiesFile + ' ' + cml2CompileRulesFile )
+        os.system ( toolsDirectory +  '/cml2header.py -o ' + cml2ConfigHeaderFile + ' -i ' + cml2ConfigPropertiesFile )
 
-libraryEnvironment = environment.Clone (
-    CC = 'arm-none-linux-gnueabi-gcc',
-    CCFLAGS = [ '-g' , '-nostdinc' , '-nostdlib' , '-ffreestanding' ] ,
-    LINKFLAGS = [ '-nostdlib' ] ,
-    ENV = { 'PATH' : os.environ['PATH'] } ,
-    LIBS = 'gcc' ,
-    ARCH = arch , 
-    PLATFORM = platform )
+    if len ( COMMAND_LINE_TARGETS ) != 1 :
+        print '#### Warning####: configure is part of the command line, all the other targets are being ignored as this is a configure step.'
+    Command ( 'configure' ,  [ '#configs/arm.cml' ] , performCML2Configuration )
+    Clean ( 'configure' , buildDirectory )
 
-libs = { }
-crts = { }
-for variant in [ 'baremetal' , 'userspace' ] :
-    ( libs[variant] , crts[variant] ) = SConscript ( 'libs/c/SConscript' , variant_dir = buildDirectory + '/lib/c/' + variant , duplicate = 0 , exports = { 'environment' : libraryEnvironment , 'variant' : variant } )
+else :
 
-libelf = SConscript ( 'libs/elf/SConscript' , variant_dir = buildDirectory + '/lib/elf' , duplicate = 0 , exports = { 'environment' : libraryEnvironment , 'lib' : libs['baremetal'] } )
+    if not os.path.exists ( cml2ConfigPropertiesFile ) :
+        print "####\n#### Configuration has not been undertaken, please run 'scons configure'.\n####"
+        Exit ( )
 
-cmlCompiledRules = Command ( '#' + buildDirectory + '/rules.out' , '#configs/' + arch + '.cml' , cml2ToolsDirectory + '/cmlcompile.py -o $TARGET $SOURCE' )
-cmlConfiguredRules = Command ( '#' + buildDirectory + '/config.out' , cmlCompiledRules , cml2ToolsDirectory + '/cmlconfigure.py -c -o $TARGET $SOURCE' )
-cmlConfigHeader = Command ( '#' + buildDirectory + '/config.h' , cmlConfiguredRules , toolsDirectory + '/cml2header.py -o $TARGET -i $SOURCE' )
+    def processCML2Config ( ) :
+        configItems = { }
+        with file ( cml2ConfigPropertiesFile ) as configFile :
+            for line in configFile :
+                item = line.split ( '=' )
+                if len ( item ) == 2 :
+                    configItems[item[0].strip ( )] = ( item[1].strip ( ) == 'y' )
+        return configItems
+                
+    baseEnvironment = Environment ( tools = [ 'gnulink' , 'gcc' , 'gas' , 'ar' ] )
 
-Alias ( 'configure' , cmlConfigHeader )
-if 'configure' in COMMAND_LINE_TARGETS:
-    AlwaysBuild ( cmlConfiguredRules )
+    configuration = Configure ( baseEnvironment , config_h =  'config.h' )
+    configData = processCML2Config ( )
+    arch = None
+    platform = None
+    subarch = None
+    for key , value in configData.items ( ) :
+        if value :
+            items = key.split ( '_' )
+            if items[0] == 'ARCH' : arch = items[1].lower ( )
+    for key , value in configData.items ( ) :
+        if value :
+            items = key.split ( '_' )
+            if items[0] == arch.upper ( ) :
+                if items[1] == 'PLATFORM' : platform = items[2].lower ( )
+                if items[1] == 'SUBARCH' : subarch = items[2].lower ( )
+            if items[0] == 'DRIVER' :
+                pass
+    configuration.Define ( '__ARCH__' , arch ) 
+    configuration.Define ( '__PLATFORM__' , platform )
+    configuration.Define ( '__SUBARCH__' , subarch )
+    baseEnvironment = configuration.Finish ( )
 
-kernelEnvironment = environment.Clone (
-    CC = 'arm-none-eabi-gcc' ,
-    # We don't use -nostdinc because sometimes we need standard headers, such as stdarg.h e.g. for variable
-    # args, as in printk().
-    CCFLAGS = [ '-g' , '-mcpu=arm926ej-s' , '-nostdlib' , '-ffreestanding' , '-std=gnu99' , '-Wall' , '-Werror' ] ,
-    LINKFLAGS = [ '-nostdlib' , '-T' + linkerScript ] ,
-    ASFLAGS = [ '-D__ASSEMBLY__' ] ,
-    PROGSUFFIX = '.axf' ,
-    ENV = { 'PATH' : os.environ['PATH'] } ,
-    LIBS = 'gcc' ,  # libgcc.a is required for the division routines.
-    CPPPATH = includeDirectory ,
-    CPPFLAGS = [ '-include l4/config.h' , '-include l4/macros.h' , '-include l4/types.h' , '-D__KERNEL__' ] )
+    linkerScript = includeDirectory + '/l4/arch/' + arch + '/mylinks.lds'
 
-Clean ( '.' , [ buildDirectory ] )
+    libraryEnvironment = baseEnvironment.Clone (
+        CC = 'arm-none-linux-gnueabi-gcc',
+        CCFLAGS = [ '-g' , '-nostdinc' , '-nostdlib' , '-ffreestanding' ] ,
+        LINKFLAGS = [ '-nostdlib' ] ,
+        ENV = { 'PATH' : os.environ['PATH'] } ,
+        LIBS = 'gcc' ,
+        ARCH = arch , 
+        PLATFORM = platform )
+
+    libs = { }
+    crts = { }
+    for variant in [ 'baremetal' , 'userspace' ] :
+        ( libs[variant] , crts[variant] ) = SConscript ( 'libs/c/SConscript' , variant_dir = buildDirectory + '/lib/c/' + variant , duplicate = 0 , exports = { 'environment' : libraryEnvironment , 'variant' : variant } )
+
+    libelf = SConscript ( 'libs/elf/SConscript' , variant_dir = buildDirectory + '/lib/elf' , duplicate = 0 , exports = { 'environment' : libraryEnvironment } )
+
+    kernelEnvironment = baseEnvironment.Clone (
+        CC = 'arm-none-eabi-gcc' ,
+        # We don't use -nostdinc because sometimes we need standard headers, such as stdarg.h e.g. for variable
+        # args, as in printk().
+        CCFLAGS = [ '-g' , '-mcpu=arm926ej-s' , '-nostdlib' , '-ffreestanding' , '-std=gnu99' , '-Wall' , '-Werror' ] ,
+        LINKFLAGS = [ '-nostdlib' , '-T' + linkerScript ] ,
+        ASFLAGS = [ '-D__ASSEMBLY__' ] ,
+        PROGSUFFIX = '.axf' ,
+        ENV = { 'PATH' : os.environ['PATH'] } ,
+        LIBS = 'gcc' ,  # libgcc.a is required for the division routines.
+        CPPPATH = includeDirectory ,
+        CPPFLAGS = [ '-include config.h' , '-include #' + buildDirectory + '/cml2Config.h' , '-include l4/macros.h' , '-include l4/types.h' , '-D__KERNEL__' ] )
+    
+    Default ( crts.values ( ) + libs.values ( ) + [ libelf ] )
+    
+    Clean ( '.' , [ buildDirectory ] )