scons: Build the marshal binary in a bare minimum environment

This change adds an additional bare minimum environment that includes
python only and changes the marshal binary to compile using it.

Change-Id: Id5d1ee6899796d746d8dc1a004cfe4795f040c55
Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/28428
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

diff --git a/SConstruct b/SConstruct
index 33451481297dca28b322e2efdf12c25cd16d3c45..ba4affaf7ac9c62038096511a9a0b6aec2062839 100755 (executable)
--- a/SConstruct
+++ b/SConstruct
@@ -709,6 +709,10 @@ 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
+base_py_env = main.Clone()
+
 # On Solaris you need to use libsocket for socket ops
 if not conf.CheckLibWithHeader(None, 'sys/socket.h', 'C++', 'accept(0,0,0);'):
    if not conf.CheckLibWithHeader('socket', 'sys/socket.h',
@@ -1100,8 +1104,6 @@ for root, dirs, files in os.walk(ext_dir):
 gdb_xml_dir = joinpath(ext_dir, 'gdb-xml')
 Export('gdb_xml_dir')
 
-main.Prepend(CPPPATH=Dir('ext/pybind11/include/'))
-
 ###################################################
 #
 # This builder and wrapper method are used to set up a directory with
@@ -1259,7 +1261,8 @@ for variant_path in variant_paths:
     # 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')
+    SConscript('src/SConscript', variant_dir=variant_path,
+               exports=['env', 'base_py_env'])
 
 # base help text
 Help('''

diff --git a/src/SConscript b/src/SConscript
index c7251fcebb71e9de11ba7bba3e9c5d55f1b76233..134e2a59883e846082276e1291ceddf22287f665 100644 (file)
--- a/src/SConscript
+++ b/src/SConscript
@@ -1,6 +1,6 @@
 # -*- mode:python -*-
 
-# Copyright (c) 2018 ARM Limited
+# Copyright (c) 2018, 2020 ARM Limited
 #
 # The license below extends only to copyright in the software and shall
 # not be construed as granting a license to any other intellectual
@@ -1140,7 +1140,7 @@ 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 = env.Program('marshal', 'python/marshal.cc')[0]
+py_marshal = base_py_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
@@ -1196,8 +1196,8 @@ EmbeddedPython embedded_${sym}(
     code.write(str(target[0]))
 
 for source in PySource.all:
-    env.Command(source.cpp, [ py_marshal, source.tnode ],
-                MakeAction(embedPyFile, Transform("EMBED PY")))
+    base_py_env.Command(source.cpp, [ py_marshal, source.tnode ],
+                        MakeAction(embedPyFile, Transform("EMBED PY")))
     Source(source.cpp, tags=source.tags, add_tags='python')
 
 ########################################################################