python: Add mechanism to override code compiled into the exectuable

If the user sets the environment variable M5_OVERRIDE_PY_SOURCE to
True, then imports that would normally find python code compiled into
the executable will instead first check in the absolute location where
the code was found during the build of the executable.  This only
works for files in the src (or extras) directories, not automatically
generated files.

This is a developer feature!

2 files changed, 3 insertions, 1 deletions

diff --git a/src/sim/init.cc b/src/sim/init.cc
index 8057c9369..1ec09369d 100644
--- a/src/sim/init.cc
+++ b/src/sim/init.cc
@@ -154,7 +154,8 @@ initM5Python()
     while (pymod->filename) {
         PyObject *code = getCode(pymod);
         PyObject *result = PyObject_CallMethod(module, PyCC("add_module"),
-            PyCC("ssO"), pymod->filename, pymod->modpath, code);
+            PyCC("sssO"), pymod->filename, pymod->abspath, pymod->modpath,
+            code);
         if (!result) {
             PyErr_Print();
             return 1;
diff --git a/src/sim/init.hh b/src/sim/init.hh
index b0f29bf30..76cdcb74e 100644
--- a/src/sim/init.hh
+++ b/src/sim/init.hh
@@ -37,6 +37,7 @@
 struct EmbeddedPyModule
 {
     const char *filename;
+    const char *abspath;
     const char *modpath;
     const char *code;
     const char *code_end;