sim: revamp unserialization procedure

Replace direct call to unserialize() on each SimObject with a pair of
calls for better control over initialization in both ckpt and non-ckpt
cases.

If restoring from a checkpoint, loadState(ckpt) is called on each
SimObject.  The default implementation simply calls unserialize() if
there is a corresponding checkpoint section, so we get backward
compatibility for existing objects.  However, objects can override
loadState() to get other behaviors, e.g., doing other programmed
initializations after unserialize(), or complaining if no checkpoint
section is found.  (Note that the default warning for a missing
checkpoint section is now gone.)

If not restoring from a checkpoint, we call the new initState() method
on each SimObject instead.  This provides a hook for state
initializations that are only required when *not* restoring from a
checkpoint.

Given this new framework, do some cleanup of LiveProcess subclasses
and X86System, which were (in some cases) emulating initState()
behavior in startup via a local flag or (in other cases) erroneously
doing initializations in startup() that clobbered state loaded earlier
by unserialize().

1 files changed, 3 insertions, 6 deletions

diff --git a/src/sim/process.cc b/src/sim/process.cc
index f11fdcac8..d4b1fba90 100644
--- a/src/sim/process.cc
+++ b/src/sim/process.cc
@@ -100,8 +100,8 @@ template class AuxVector<uint32_t>;
 template class AuxVector<uint64_t>;
 
 Process::Process(ProcessParams * params)
-    : SimObject(params), system(params->system), checkpointRestored(false),
-    max_stack_size(params->max_stack_size)
+    : SimObject(params), system(params->system),
+      max_stack_size(params->max_stack_size)
 {
     string in = params->input;
     string out = params->output;
@@ -233,7 +233,7 @@ Process::findFreeContext()
 }
 
 void
-Process::startup()
+Process::initState()
 {
     if (contextIds.empty())
         fatal("Process %s is not associated with any HW contexts!\n", name());
@@ -537,9 +537,6 @@ Process::unserialize(Checkpoint *cp, const std::string &section)
     // find the param in the checkpoint if you wanted to, like set a default
     // but in this case we'll just stick with the instantianted value if not
     // found.   
-
-    checkpointRestored = true;
-
 }