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/cpu/SConscript

@@ -85,13 +85,12 @@ Source('pc_event.cc')
 SimObject('FuncUnit.py', sim_objects=['OpDesc', 'FUDesc'], enums=['OpClass'])
 SimObject('StaticInstFlags.py', enums=['StaticInstFlags'])
 
-if env['TARGET_ISA'] == 'null':
+if env['CONF']['TARGET_ISA'] == 'null':
     Return()
 
 # Only build the protobuf instructions tracer if we have protobuf support.
-if env['HAVE_PROTOBUF']:
-    SimObject('InstPBTrace.py', sim_objects=['InstPBTrace'])
-    Source('inst_pb_trace.cc')
+SimObject('InstPBTrace.py', sim_objects=['InstPBTrace'], tags='protobuf')
+Source('inst_pb_trace.cc', tags='protobuf')
 
 SimObject('CheckerCPU.py', sim_objects=['CheckerCPU'])
 

src/cpu/kvm/SConscript

@@ -37,7 +37,8 @@
 
 Import('*')
 
-if not env['USE_KVM'] or env['TARGET_ISA'] != env['KVM_ISA']:
+if not env['CONF']['USE_KVM'] or \
+        env['CONF']['TARGET_ISA'] != env['CONF']['KVM_ISA']:
     Return()
 
 SimObject('KvmVM.py', sim_objects=['KvmVM'])

src/cpu/kvm/SConsopts

@@ -42,7 +42,7 @@ with gem5_scons.Configure(main) as conf:
     # the types as a fall back.
     # The default value of KVM_ISA should serialize to a string in the
     # C++ header and test False in Scons/Python.
-    conf.env['KVM_ISA'] = ''
+    conf.env['CONF']['KVM_ISA'] = ''
     if not conf.CheckHeader('linux/kvm.h', '<>'):
         print("Info: Compatible header file <linux/kvm.h> not found, "
               "disabling KVM support.")
@@ -52,33 +52,28 @@ with gem5_scons.Configure(main) as conf:
     elif host_isa == 'x86_64':
         if conf.CheckTypeSize('struct kvm_xsave',
                 '#include <linux/kvm.h>') != 0:
-            conf.env['KVM_ISA'] = 'x86'
+            conf.env['CONF']['KVM_ISA'] = 'x86'
         else:
             warning("KVM on x86 requires xsave support in kernel headers.")
     elif host_isa in ('armv7l', 'aarch64'):
-        conf.env['KVM_ISA'] = 'arm'
+        conf.env['CONF']['KVM_ISA'] = 'arm'
     else:
         warning("Failed to determine host ISA.")
 
-    if conf.env['KVM_ISA']:
+    if conf.env['CONF']['KVM_ISA']:
         # Check if the exclude_host attribute is available. We want this to
         # get accurate instruction counts in KVM.
-        conf.env['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
+        conf.env['CONF']['HAVE_PERF_ATTR_EXCLUDE_HOST'] = conf.CheckMember(
             'linux/perf_event.h', 'struct perf_event_attr', 'exclude_host')
 
         # Warn about missing optional functionality
-        if not conf.env['HAVE_PERF_ATTR_EXCLUDE_HOST']:
+        if not conf.env['CONF']['HAVE_PERF_ATTR_EXCLUDE_HOST']:
             warning("perf_event headers lack support for the exclude_host "
                     "attribute. KVM instruction counts will be inaccurate.")
 
-        export_vars.append('HAVE_PERF_ATTR_EXCLUDE_HOST')
-
-if main['KVM_ISA']:
+if main['CONF']['KVM_ISA']:
     sticky_vars.Add(BoolVariable('USE_KVM',
                 'Enable hardware virtualized (KVM) CPU models', True))
 else:
-    main['USE_KVM'] = False
-    export_vars.append('USE_KVM')
+    main['CONF']['USE_KVM'] = False
     warning("Can not enable KVM, host seems to lack KVM support")
-
-export_vars.append('KVM_ISA')

src/cpu/minor/SConscript

@@ -40,7 +40,7 @@
 
 Import('*')
 
-if env['TARGET_ISA'] != 'null':
+if env['CONF']['TARGET_ISA'] != 'null':
     SimObject('BaseMinorCPU.py', sim_objects=[
         'MinorOpClass', 'MinorOpClassSet', 'MinorFUTiming', 'MinorFU',
         'MinorFUPool', 'BaseMinorCPU'],

src/cpu/o3/SConscript

@@ -30,7 +30,7 @@ import sys
 
 Import('*')
 
-if env['TARGET_ISA'] != 'null':
+if env['CONF']['TARGET_ISA'] != 'null':
     SimObject('FUPool.py', sim_objects=['FUPool'])
     SimObject('FuncUnitConfig.py', sim_objects=[])
     SimObject('BaseO3CPU.py', sim_objects=['BaseO3CPU'], enums=[

src/cpu/o3/probe/SConscript

@@ -37,12 +37,11 @@
 
 Import('*')
 
-if env['TARGET_ISA'] != 'null':
+if env['CONF']['TARGET_ISA'] != 'null':
     SimObject('SimpleTrace.py', sim_objects=['SimpleTrace'])
     Source('simple_trace.cc')
     DebugFlag('SimpleTrace')
 
-    if env['HAVE_PROTOBUF']:
-        SimObject('ElasticTrace.py', sim_objects=['ElasticTrace'])
-        Source('elastic_trace.cc')
-        DebugFlag('ElasticTrace')
+    SimObject('ElasticTrace.py', sim_objects=['ElasticTrace'], tags='protobuf')
+    Source('elastic_trace.cc', tags='protobuf')
+    DebugFlag('ElasticTrace', tags='protobuf')

src/cpu/pred/SConscript

@@ -28,7 +28,7 @@
 
 Import('*')
 
-if env['TARGET_ISA'] == 'null':
+if env['CONF']['TARGET_ISA'] == 'null':
     Return()
 
 SimObject('BranchPredictor.py', sim_objects=[

src/cpu/simple/SConscript

@@ -28,7 +28,7 @@
 
 Import('*')
 
-if env['TARGET_ISA'] != 'null':
+if env['CONF']['TARGET_ISA'] != 'null':
     SimObject('BaseAtomicSimpleCPU.py', sim_objects=['BaseAtomicSimpleCPU'])
     Source('atomic.cc')
 

src/cpu/simple/probes/SConscript

@@ -28,6 +28,6 @@
 
 Import('*')
 
-if env['TARGET_ISA'] != 'null':
+if env['CONF']['TARGET_ISA'] != 'null':
     SimObject('SimPoint.py', sim_objects=['SimPoint'])
     Source('simpoint.cc')

src/cpu/testers/directedtest/SConscript

@@ -35,7 +35,7 @@ Import('*')
 # When this dependency is removed, the ruby tester should be compiled
 # independently from Ruby
 #
-if env['PROTOCOL'] == 'None':
+if env['CONF']['PROTOCOL'] == 'None':
     Return()
 
 SimObject('RubyDirectedTester.py', sim_objects=[

src/cpu/testers/garnet_synthetic_traffic/SConscript

@@ -28,7 +28,7 @@
 
 Import('*')
 
-if env['PROTOCOL'] == 'None':
+if env['CONF']['PROTOCOL'] == 'None':
     Return()
 
 SimObject('GarnetSyntheticTraffic.py', sim_objects=['GarnetSyntheticTraffic'])

src/cpu/testers/gpu_ruby_test/SConscript

@@ -31,10 +31,10 @@
 
 Import('*')
 
-if not env['BUILD_GPU']:
+if not env['CONF']['BUILD_GPU']:
     Return()
 
-if env['PROTOCOL'] == 'None':
+if env['CONF']['PROTOCOL'] == 'None':
     Return()
 
 SimObject('ProtocolTester.py', sim_objects=['ProtocolTester'])

src/cpu/testers/rubytest/SConscript

@@ -35,7 +35,7 @@ Import('*')
 # When this dependency is removed, the ruby tester should be compiled
 # independently from Ruby
 #
-if env['PROTOCOL'] == 'None':
+if env['CONF']['PROTOCOL'] == 'None':
     Return()
 
 SimObject('RubyTester.py', sim_objects=['RubyTester'])

src/cpu/testers/traffic_gen/SConscript

@@ -65,8 +65,7 @@ if env['USE_PYTHON']:
 
 # Only build the traffic generator if we have support for protobuf as the
 # tracing relies on it
-if env['HAVE_PROTOBUF']:
-    SimObject('TrafficGen.py', sim_objects=['TrafficGen'])
-    Source('trace_gen.cc')
-    Source('traffic_gen.cc')
+SimObject('TrafficGen.py', sim_objects=['TrafficGen'], tags='protobuf')
+Source('trace_gen.cc', tags='protobuf')
+Source('traffic_gen.cc', tags='protobuf')
 

src/cpu/trace/SConscript

@@ -1,12 +1,11 @@
 Import('*')
 
-if env['TARGET_ISA'] == 'null':
+if env['CONF']['TARGET_ISA'] == 'null':
     Return()
 
 # Only build TraceCPU if we have support for protobuf as TraceCPU relies on it
-if env['HAVE_PROTOBUF']:
-    SimObject('TraceCPU.py', sim_objects=['TraceCPU'])
-    Source('trace_cpu.cc')
+SimObject('TraceCPU.py', sim_objects=['TraceCPU'], tags='protobuf')
+Source('trace_cpu.cc', tags='protobuf')
 
 DebugFlag('TraceCPUData')
 DebugFlag('TraceCPUInst')