scons: Put all config variables in an env['CONF'] sub-dict.

This makes what are configuration and what are internal SCons variables
explicit and separate, and makes it unnecessary to call out what
variables to export to C++.

These variables will also be plumbed into and out of kconfiglib in later
changes.

Change-Id: Iaf5e098d7404af06285c421dbdf8ef4171b3f001
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/56892
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/systemc/SConscript

@@ -25,7 +25,7 @@
 
 Import('*')
 
-if not env['USE_SYSTEMC']:
+if not env['CONF']['USE_SYSTEMC']:
     Return()
 
 env.UseSystemcCheck(warn=True)

src/systemc/SConsopts

@@ -44,5 +44,7 @@ def use_systemc_check(env, warn=False):
 
 main.AddMethod(use_systemc_check, 'UseSystemcCheck')
 
+main['CONF']['USE_SYSTEMC'] = main.UseSystemcCheck()
+
 sticky_vars.Add(BoolVariable('USE_SYSTEMC', 'Enable SystemC API support',
                              main.UseSystemcCheck()))

src/systemc/channel/SConscript

@@ -25,7 +25,7 @@
 
 Import('*')
 
-if env['USE_SYSTEMC']:
+if env['CONF']['USE_SYSTEMC']:
     Source('messages.cc')
     Source('sc_clock.cc')
     Source('sc_event_queue.cc')

src/systemc/core/SConscript

@@ -27,7 +27,7 @@ import gem5_scons
 
 Import('*')
 
-if env['USE_SYSTEMC']:
+if env['CONF']['USE_SYSTEMC']:
     SimObject('SystemC.py', sim_objects=[
         'SystemC_Kernel', 'SystemC_ScObject', 'SystemC_ScModule'])
 

src/systemc/dt/SConscript

@@ -25,5 +25,5 @@
 
 Import('*')
 
-if env['USE_SYSTEMC']:
+if env['CONF']['USE_SYSTEMC']:
     Source('sc_mempool.cc')

src/systemc/dt/bit/SConscript

@@ -25,7 +25,7 @@
 
 Import('*')
 
-if env['USE_SYSTEMC']:
+if env['CONF']['USE_SYSTEMC']:
     Source('messages.cc')
     Source('sc_bit.cc')
     Source('sc_bv_base.cc')

src/systemc/dt/fx/SConscript

@@ -25,7 +25,7 @@
 
 Import('*')
 
-if env['USE_SYSTEMC']:
+if env['CONF']['USE_SYSTEMC']:
     Source('messages.cc')
     Source('sc_fxcast_switch.cc')
     Source('sc_fxdefs.cc')

src/systemc/dt/int/SConscript

@@ -27,7 +27,7 @@ Import('*')
 
 from gem5_scons.util import compareVersions
 
-if env['USE_SYSTEMC']:
+if env['CONF']['USE_SYSTEMC']:
     if env['GCC'] and compareVersions(env['CXXVERSION'], '10.0') >= 0:
         disable_false_positives = {
             "CCFLAGS": [ "-Wno-array-bounds",

src/systemc/dt/misc/SConscript

@@ -25,6 +25,6 @@
 
 Import('*')
 
-if env['USE_SYSTEMC']:
+if env['CONF']['USE_SYSTEMC']:
     Source('sc_concatref.cc')
     Source('sc_value_base.cc')

src/systemc/python/SConscript

@@ -25,7 +25,7 @@
 
 Import('*')
 
-if not env['USE_SYSTEMC'] or not env['USE_PYTHON']:
+if not env['CONF']['USE_SYSTEMC'] or not env['USE_PYTHON']:
     Return()
 
 PySource('m5', 'systemc.py')

src/systemc/tests/SConscript

@@ -25,7 +25,7 @@
 
 Import('*')
 
-if env['USE_SYSTEMC'] and GetOption('with_systemc_tests'):
+if env['CONF']['USE_SYSTEMC'] and GetOption('with_systemc_tests'):
 
     from gem5_scons import Transform
 

src/systemc/tlm_bridge/SConscript

@@ -25,7 +25,7 @@
 
 Import('*')
 
-if not env['USE_SYSTEMC']:
+if not env['CONF']['USE_SYSTEMC']:
     Return()
 
 SimObject('TlmBridge.py', sim_objects=[

src/systemc/tlm_core/2/generic_payload/SConscript

@@ -25,6 +25,6 @@
 
 Import('*')
 
-if env['USE_SYSTEMC']:
+if env['CONF']['USE_SYSTEMC']:
     Source('gp.cc')
     Source('phase.cc')

src/systemc/tlm_core/2/quantum/SConscript

@@ -25,7 +25,7 @@
 
 Import('*')
 
-if env['USE_SYSTEMC']:
+if env['CONF']['USE_SYSTEMC']:
     Source('global_quantum.cc')
     if env['USE_PYTHON']:
         Source('global_quantum_python.cc')

src/systemc/tlm_utils/SConscript

@@ -25,6 +25,6 @@
 
 Import('*')
 
-if env['USE_SYSTEMC']:
+if env['CONF']['USE_SYSTEMC']:
     Source('convenience_socket_bases.cc')
     Source('instance_specific_extensions.cc')

src/systemc/utils/SConscript

@@ -25,7 +25,7 @@
 
 Import('*')
 
-if env['USE_SYSTEMC']:
+if env['CONF']['USE_SYSTEMC']:
     Source('functions.cc')
     Source('messages.cc')
     Source('report.cc')