scons,python: Fix `--without-python` flag

Even with the `--without-python` flag, checks were still done to ensure
the correct version of Python was being used. This commit fixes this so
these checks are not performed when `--without-python` is enabled.

Change-Id: I2242f2971a49ef28cff229ad0337bce0a998413d
Issue-on: https://gem5.atlassian.net/browse/GEM5-880
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39715
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Lukas Steiner <lsteiner@rhrk.uni-kl.de>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

diff --git a/SConstruct b/SConstruct
index 4cf2f1059e58c231b8a460d1205ea513aa60a5d5..f744c77df65868c601db3973d7b0003449e3afcf 100755 (executable)
--- a/SConstruct
+++ b/SConstruct
@@ -709,22 +709,25 @@ if main['USE_PYTHON']:
         if not conf.CheckLib(lib):
             error("Can't find library %s required by python." % lib)
 
-main.Prepend(CPPPATH=Dir('ext/pybind11/include/'))
-# Bare minimum environment that only includes python
-marshal_env = main.Clone()
-marshal_env.Append(CCFLAGS='$MARSHAL_CCFLAGS_EXTRA')
-marshal_env.Append(LINKFLAGS='$MARSHAL_LDFLAGS_EXTRA')
-py_version = conf.CheckPythonLib()
-if not py_version:
-    error("Can't find a working Python installation")
-
-# Found a working Python installation. Check if it meets minimum
-# requirements.
-if py_version[0] < 3 or \
-   (py_version[0] == 3 and py_version[1] < 6):
-    error('Python version too old. Version 3.6 or newer is required.')
-elif py_version[0] > 3:
-    warning('Python version too new. Python 3 expected.')
+    main.Prepend(CPPPATH=Dir('ext/pybind11/include/'))
+
+    marshal_env = main.Clone()
+
+    # Bare minimum environment that only includes python
+    marshal_env.Append(CCFLAGS='$MARSHAL_CCFLAGS_EXTRA')
+    marshal_env.Append(LINKFLAGS='$MARSHAL_LDFLAGS_EXTRA')
+
+    py_version = conf.CheckPythonLib()
+    if not py_version:
+        error("Can't find a working Python installation")
+
+    # Found a working Python installation. Check if it meets minimum
+    # requirements.
+    if py_version[0] < 3 or \
+    (py_version[0] == 3 and py_version[1] < 6):
+        error('Python version too old. Version 3.6 or newer is required.')
+    elif py_version[0] > 3:
+        warning('Python version too new. Python 3 expected.')
 
 # On Solaris you need to use libsocket for socket ops
 if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
@@ -1271,10 +1274,13 @@ Build variables for {dir}:
     env.Append(CCFLAGS='$CCFLAGS_EXTRA')
     env.Append(LINKFLAGS='$LDFLAGS_EXTRA')
 
+    exports=['env']
+    if main['USE_PYTHON']:
+        exports.append('marshal_env')
+
     # The src/SConscript file sets up the build rules in 'env' according
     # to the configured variables.  It returns a list of environments,
     # one for each variant build (debug, opt, etc.)
-    SConscript('src/SConscript', variant_dir=variant_path,
-               exports=['env', 'marshal_env'])
+    SConscript('src/SConscript', variant_dir=variant_path, exports=exports)
 
 atexit.register(summarize_warnings)

diff --git a/src/SConscript b/src/SConscript
index 81a1b4d09e8b373d82da125cccc5fffc82c5145b..74b9516a0739465aec283fbc58cd2a523dc60d9d 100644 (file)
--- a/src/SConscript
+++ b/src/SConscript
@@ -1208,11 +1208,6 @@ env.Command('sim/tags.cc', None,
                        Transform("VER TAGS")))
 env.AlwaysBuild(tags)
 
-# Build a small helper that marshals the Python code using the same
-# version of Python as gem5. This is in an unorthodox location to
-# avoid building it for every variant.
-py_marshal = marshal_env.Program('marshal', 'python/marshal.cc')[0]
-
 # Embed python files.  All .py files that have been indicated by a
 # PySource() call in a SConscript need to be embedded into the M5
 # library.  To do that, we compile the file to byte code, marshal the
@@ -1266,10 +1261,16 @@ EmbeddedPython embedded_${sym}(
 ''')
     code.write(str(target[0]))
 
-for source in PySource.all:
-    marshal_env.Command(source.cpp, [ py_marshal, source.tnode ],
+if main['USE_PYTHON']:
+    # Build a small helper that marshals the Python code using the same
+    # version of Python as gem5. This is in an unorthodox location to
+    # avoid building it for every variant.
+    py_marshal = marshal_env.Program('marshal', 'python/marshal.cc')[0]
+
+    for source in PySource.all:
+        marshal_env.Command(source.cpp, [ py_marshal, source.tnode ],
                         MakeAction(embedPyFile, Transform("EMBED PY")))
-    Source(source.cpp, tags=source.tags, add_tags='python')
+        Source(source.cpp, tags=source.tags, add_tags='python')
 
 ########################################################################
 #