scons: Move python path management out of the SConstruct.

Make site_init.py manage sys.path, and the "default" tool set
PYTHONPATH on any environment that's created. The paths to add are
tracked in a common gem5_python_paths.py.

Change-Id: I3387d4394d47a2f9c83322644cfd05909c6890fa
Reviewed-on: https://gem5-review.googlesource.com/5564
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

3 files changed, 63 insertions, 0 deletions

diff --git a/site_scons/gem5_python_paths.py b/site_scons/gem5_python_paths.py
new file mode 100644
index 000000000..2833a4cc0
--- /dev/null
+++ b/site_scons/gem5_python_paths.py
@@ -0,0 +1,52 @@
+# Copyright (c) 2013, 2015-2017 ARM Limited
+# All rights reserved.
+#
+# The license below extends only to copyright in the software and shall
+# not be construed as granting a license to any other intellectual
+# property including but not limited to intellectual property relating
+# to a hardware implementation of the functionality of the software
+# licensed hereunder.  You may use the software subject to the license
+# terms below provided that you ensure that this notice is replicated
+# unmodified and in its entirety in all distributions of the software,
+# modified or unmodified, in source code or in binary form.
+#
+# Copyright (c) 2011 Advanced Micro Devices, Inc.
+# Copyright (c) 2009 The Hewlett-Packard Development Company
+# Copyright (c) 2004-2005 The Regents of The University of Michigan
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import SCons.Node.FS
+
+fs = SCons.Node.FS.get_default_fs()
+root = fs.Dir('#')
+extra_python_nodes = [
+    root.Dir('src').Dir('python').srcnode(), # gem5 includes
+    root.Dir('ext').Dir('ply').srcnode(), # ply is used by several files
+]
+
+extra_python_paths = [ node.abspath for node in extra_python_nodes ]
+
+__all__ = ['extra_python_paths']
diff --git a/site_scons/site_init.py b/site_scons/site_init.py
index 505fe6acb..6d9d24d30 100644
--- a/site_scons/site_init.py
+++ b/site_scons/site_init.py
@@ -38,6 +38,8 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+from gem5_python_paths import extra_python_paths
+
 # Check for recent-enough Python and SCons versions.
 try:
     # Really old versions of scons only take two options for the
@@ -66,3 +68,5 @@ For more details, see:
     http://gem5.org/wiki/index.php/Using_a_non-default_Python_installation
 """
     raise
+
+sys.path[1:1] = extra_python_paths
diff --git a/site_scons/site_tools/default.py b/site_scons/site_tools/default.py
index 2d32b56bd..73c4a9eaf 100644
--- a/site_scons/site_tools/default.py
+++ b/site_scons/site_tools/default.py
@@ -39,10 +39,13 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 import os
+import sys
 
 import SCons.Tool
 import SCons.Tool.default
 
+from gem5_python_paths import extra_python_paths
+
 def common_config(env):
     # export TERM so that clang reports errors in color
     use_vars = set([ 'AS', 'AR', 'CC', 'CXX', 'HOME', 'LD_LIBRARY_PATH',
@@ -71,6 +74,10 @@ def common_config(env):
     env.root = env.Dir('#')
     env.srcdir = env.root.Dir('src')
 
+    # add useful python code PYTHONPATH so it can be used by subprocesses
+    # as well
+    env.AppendENVPath('PYTHONPATH', extra_python_paths)
+
 gem5_tool_list = [
     'git',
     'mercurial',