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sim: add support for checkpoint downgrading

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This commit supports the use case of transitioning tags and their
associated checkpoint rewrites out of use for whatever reason.  Just
replace the upgrader() method with a downgrader() method that performs
the appropriate inverse operation.

The tag name is still used, but only in this negative, 'zombie' state,
as it will be removed from the tags in the checkpoint and gem5 binary.

Change-Id: If9d26cccfe8449e026762b1a72f0c2ae5a9cf2d7
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
This commit is contained in:
Curtis Dunham 2017-02-14 15:09:18 -06:00
parent e9311a59ed
commit 72e74aed0a
1 changed files with 38 additions and 17 deletions
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51
util/cpt_upgrader.py
View file

@ -1,6 +1,6 @@
#!/usr/bin/env python2
# Copyright (c) 2012-2013,2015 ARM Limited
# Copyright (c) 2012-2013,2015-2016 ARM Limited
# All rights reserved
#
# The license below extends only to copyright in the software and shall
@ -57,6 +57,13 @@
# be isa specific the method can verify the isa and use regexes to find the
# correct sections that need to be updated.
# It is also possible to use this mechanism to revert prior tags. In this
# case, implement a downgrade() method instead. Dependencies should still
# work naturally - a tag depending on a tag with a downgrader means that it
# insists on the other tag being removed and its downgrader executed before
# its upgrader (or downgrader) can run. It is still the case that a tag
# can only be used once.
import ConfigParser
import glob, types, sys, os
@ -73,6 +80,7 @@ def verboseprint(*args):
class Upgrader:
tag_set = set()
untag_set = set() # tags to remove by downgrading
by_tag = {}
legacy = {}
def __init__(self, filename):
@ -86,19 +94,26 @@ class Upgrader:
elif isinstance(self.depends, str):
self.depends = [self.depends]
if not hasattr(self, 'upgrader'):
print "Error: no upgrader method for", self.tag
if hasattr(self, 'upgrader'):
if not isinstance(self.upgrader, types.FunctionType):
print "Error: 'upgrader' for %s is %s, not function" \
% (self.tag, type(self))
sys.exit(1)
elif not isinstance(self.upgrader, types.FunctionType):
print "Error: 'upgrader' for %s is %s, not function", \
self.tag, type(self)
Upgrader.tag_set.add(self.tag)
elif hasattr(self, 'downgrader'):
if not isinstance(self.downgrader, types.FunctionType):
print "Error: 'downgrader' for %s is %s, not function" \
% (self.tag, type(self))
sys.exit(1)
Upgrader.untag_set.add(self.tag)
else:
print "Error: no upgrader or downgrader method for", self.tag
sys.exit(1)
if hasattr(self, 'legacy_version'):
Upgrader.legacy[self.legacy_version] = self
Upgrader.by_tag[self.tag] = self
Upgrader.tag_set.add(self.tag)
def ready(self, tags):
for dep in self.depends:
@ -106,9 +121,15 @@ class Upgrader:
return False
return True
def upgrade(self, cpt):
(self.upgrader)(cpt)
def update(self, cpt, tags):
if hasattr(self, 'upgrader'):
self.upgrader(cpt)
tags.add(self.tag)
verboseprint("applied upgrade for", self.tag)
else:
self.downgrader(cpt)
tags.remove(self.tag)
verboseprint("applied downgrade for", self.tag)
@staticmethod
def get(tag):
@ -173,23 +194,23 @@ def process_file(path, **kwargs):
# If the current checkpoint has a tag we don't know about, we have
# a divergence that (in general) must be addressed by (e.g.) merging
# simulator support for its changes.
unknown_tags = tags - Upgrader.tag_set
unknown_tags = tags - (Upgrader.tag_set | Upgrader.untag_set)
if unknown_tags:
print "warning: upgrade script does not recognize the following "\
"tags in this checkpoint:", ' '.join(unknown_tags)
# Apply migrations for tags not in checkpoint, respecting dependences
to_apply = Upgrader.tag_set - tags
# Apply migrations for tags not in checkpoint and tags present for which
# downgraders are present, respecting dependences
to_apply = (Upgrader.tag_set - tags) | (Upgrader.untag_set & tags)
while to_apply:
ready = set([ t for t in to_apply if Upgrader.get(t).ready(tags) ])
if not ready:
print "could not apply these upgrades:", ' '.join(to_apply)
print "upgrade dependences impossible to resolve; aborting"
print "update dependences impossible to resolve; aborting"
exit(1)
for tag in ready:
Upgrader.get(tag).upgrade(cpt)
tags.add(tag)
Upgrader.get(tag).update(cpt, tags)
change = True
to_apply -= ready