model-checker.git
9 years agoaction: print promise number, not just ?
Brian Norris [Thu, 28 Feb 2013 19:17:42 +0000 (11:17 -0800)]
action: print promise number, not just ?

9 years agonodestack: bugfix - clear backtracking properly
Brian Norris [Thu, 28 Feb 2013 18:30:39 +0000 (10:30 -0800)]
nodestack: bugfix - clear backtracking properly

9 years agopromise: record multiple readers in the same Promise
Brian Norris [Wed, 27 Feb 2013 23:13:17 +0000 (15:13 -0800)]
promise: record multiple readers in the same Promise

This requires more adjustments throughout ModelChecker.

9 years agoun-'const' some Promises
Brian Norris [Wed, 27 Feb 2013 22:45:11 +0000 (14:45 -0800)]
un-'const' some Promises

I need to modify this Promise sometimes, so don't make it const
everywhere.

9 years agonodestack: rewrite promise-resolution "counting"
Brian Norris [Wed, 27 Feb 2013 02:42:51 +0000 (18:42 -0800)]
nodestack: rewrite promise-resolution "counting"

We don't need to perform a full check of all possible combinations of
Promises to resolve; we only perform 0 or 1 resolution.

9 years agomodel: hook up 'read-from-promise' backtracking in ModelChecker
Brian Norris [Wed, 27 Feb 2013 00:15:50 +0000 (16:15 -0800)]
model: hook up 'read-from-promise' backtracking in ModelChecker

Now we iterate over the read-from-promise set. Some things are still
missing.

9 years agonodestack: add read_from_promises backtracking
Brian Norris [Tue, 26 Feb 2013 19:13:10 +0000 (11:13 -0800)]
nodestack: add read_from_promises backtracking

This is just the basic framework for now. I still need to hook it up for
actual use in ModelChecker.

9 years agonodestack: bugfix - rewrite 'may-read-from' and 'future values' as the same set
Brian Norris [Thu, 28 Feb 2013 02:48:46 +0000 (18:48 -0800)]
nodestack: bugfix - rewrite 'may-read-from' and 'future values' as the same set

There were some subtle bugs that appeared because of the difficulty in
iterating over two separate sets that represent the "read from" set for
a particular read. Now, we expose an interface where there's just a
single pair of functions 'increment_read_from()' and
'read_from_empty()', for iterating over this set, along with a
flag-check 'get_read_from_status()', so that we know where to grab
values from (get_read_from_past() or get_future_value()).

This also does a lot of code moving and documentation in nodestack.cc,
for better readability and organization.

9 years agomodel: shorten some code
Brian Norris [Thu, 28 Feb 2013 01:54:45 +0000 (17:54 -0800)]
model: shorten some code

9 years agomodel: rename 'reads_from' to 'rf'
Brian Norris [Thu, 28 Feb 2013 01:48:48 +0000 (17:48 -0800)]
model: rename 'reads_from' to 'rf'

9 years agonodestack: rename 'read_from' to 'read_from_past'
Brian Norris [Thu, 28 Feb 2013 01:30:24 +0000 (17:30 -0800)]
nodestack: rename 'read_from' to 'read_from_past'

One step of re-architecting the reads-from set in NodeStack (i.e.,
read from past + promised future values + future values).

9 years agomodel: don't call process_read() for 2nd half of RMW/RMWC
Brian Norris [Thu, 28 Feb 2013 00:36:24 +0000 (16:36 -0800)]
model: don't call process_read() for 2nd half of RMW/RMWC

We don't need to call process_read() for the second half of an RMW or
RMWC ModelAction. Anyway, it does next-to-nothing when
'second_part_of_rmw' is true.

9 years agomodel: bugfix - correct the "equality" check for RR coherence
Brian Norris [Wed, 27 Feb 2013 23:42:17 +0000 (15:42 -0800)]
model: bugfix - correct the "equality" check for RR coherence

I made a typo when adding this RR coherence edge.

9 years agocyclegraph: bugfix - allow to compile with SUPPORT_MOD_ORDER_DUMP
Brian Norris [Wed, 27 Feb 2013 23:43:21 +0000 (15:43 -0800)]
cyclegraph: bugfix - allow to compile with SUPPORT_MOD_ORDER_DUMP

I missed an include that is only used for the mod-order dump support
code.

9 years agomodel: bugfix - correct RR coherence for Promises
Brian Norris [Wed, 27 Feb 2013 00:39:09 +0000 (16:39 -0800)]
model: bugfix - correct RR coherence for Promises

We should not skip a read just because it has an unresolved promises;
the CycleGraph can now support read-read coherence edges between any
combination of Promise and ModelAction.

9 years agocyclegraph: change Promise nodes map
Brian Norris [Tue, 26 Feb 2013 23:59:00 +0000 (15:59 -0800)]
cyclegraph: change Promise nodes map

Map from Promises to Nodes, not ModelAction (readers) to Nodes. This
will make it cleaner when more than one reader maps to the same promise
Node.

9 years agomodel: promises: eliminate threads when they "join"
Brian Norris [Tue, 26 Feb 2013 01:04:13 +0000 (17:04 -0800)]
model: promises: eliminate threads when they "join"

A thread that joins with another thread can no longer satisfy a promise
from that thread.

9 years agoschedule: remove commented-out code
Brian Norris [Tue, 26 Feb 2013 00:23:05 +0000 (16:23 -0800)]
schedule: remove commented-out code

9 years agomodel: bugfix - only allow promise satisfaction for "compatible" threads
Brian Norris [Tue, 26 Feb 2013 00:11:54 +0000 (16:11 -0800)]
model: bugfix - only allow promise satisfaction for "compatible" threads

I overlooked updating the 'compute_promises()' function when modifying
promises such that they are only resolved by a limited set of threads.
This allows compute_promises() to properly prune out those promises
which are not satisfiable by the current thread.

At the same time, move the act->is_read() check to be an ASSERT(), since
we should never see a promise generated by a non-read ModelAction.

9 years agothreads: construct Thread only with a given "parent"
Brian Norris [Mon, 25 Feb 2013 23:15:28 +0000 (15:15 -0800)]
threads: construct Thread only with a given "parent"

The Thread constructor really doesn't need to call thread_current(),
since it will always be called from model-checker context. Clean up the
use of default "parent_thrd" parameter and just pass NULL when we have
no parent.

9 years agorepush changes
Brian Demsky [Mon, 25 Feb 2013 07:28:21 +0000 (23:28 -0800)]
repush changes

9 years agofix conflicts
Brian Demsky [Mon, 25 Feb 2013 07:25:59 +0000 (23:25 -0800)]
fix conflicts
Merge branch 'master' of ssh://demsky.eecs.uci.edu/home/git/model-checker

Conflicts:
schedule.cc

9 years agofix norris mentioned bug
Brian Demsky [Mon, 25 Feb 2013 07:24:50 +0000 (23:24 -0800)]
fix norris mentioned bug

9 years agoRevert "fix scheduling stuff to get nice round robin scheduler behavior..."
Brian Norris [Mon, 25 Feb 2013 05:38:21 +0000 (21:38 -0800)]
Revert "fix scheduling stuff to get nice round robin scheduler behavior..."

This reverts commit 30999f20b8426081e676adfc76d1c4af7b941e8e.

This commit triggers assertions and therefore cannot be used:

$ ./run.sh test/rmwprog.o
+ test/rmwprog.o
Error: assertion failed in model.cc at line 2424
stack trace:
  ./libmodel.so : ModelChecker::resolve_promises(ModelAction*)+0x3bd
  ./libmodel.so : ModelChecker::process_write(ModelAction*)+0x21
  ./libmodel.so : ModelChecker::check_current_action(ModelAction*)+0x42b
  ./libmodel.so : ModelChecker::take_step(ModelAction*)+0x39
  ./libmodel.so : ModelChecker::run()+0xa5
  ./libmodel.so : ()+0x1a3a3
  ./libmodel.so : ()+0x1e786
  ./libmodel.so : main()+0x3c
  /lib/x86_64-linux-gnu/libc.so.6 : __libc_start_main()+0xed
  test/rmwprog.o() [0x400789]
Execution 11: INFEASIBLE: [unresolved promise]
---------------------------------------------------------------------
(   0) Thread: 0    Action: uninitialized   MO: relaxed  Loc:       0x601078   Value: 0                           CV: ( 0,  0)
(   1) Thread: 1    Action: thread start    MO: seq_cst  Loc: 0x7f6cd2016898   Value: 0xdeadbeef                  CV: ( 0,  1)
(   2) Thread: 1    Action: init atomic     MO: relaxed  Loc:       0x601078   Value: 0                           CV: ( 0,  2)
(   3) Thread: 1    Action: thread create   MO: seq_cst  Loc: 0x7f6cd1410590   Value: 0x7f6cd1410560              CV: ( 0,  3)
(   4) Thread: 2    Action: thread start    MO: seq_cst  Loc: 0x7f6cd2016e08   Value: 0xdeadbeef                  CV: ( 0,  3,  4)
(   5) Thread: 2    Action: atomic rmw      MO: relaxed  Loc:       0x601078   Value: 0x1                 Rf: 9   CV: ( 0,  3,  5)
(   6) Thread: 1    Action: thread create   MO: seq_cst  Loc: 0x7f6cd14105a0   Value: 0x7f6cd1410560              CV: ( 0,  6,  0)
(   7) Thread: 3    Action: thread start    MO: seq_cst  Loc: 0x7f6cd2017338   Value: 0xdeadbeef                  CV: ( 0,  6,  0,  7)
(   8) Thread: 2    Action: atomic rmw      MO: relaxed  Loc:       0x601078   Value: 0x2                 Rf: 5   CV: ( 0,  3,  8,  0)
(   9) Thread: 3    Action: atomic rmw      MO: relaxed  Loc:       0x601078   Value: 0                   Rf: 2   CV: ( 0,  6,  0,  9)
HASH 1973598524
---------------------------------------------------------------------

Add breakpoint to line 50 in file common.cc.

9 years agofix scheduling stuff to get nice round robin scheduler behavior...
Brian Demsky [Mon, 25 Feb 2013 04:59:46 +0000 (20:59 -0800)]
fix scheduling stuff to get nice round robin scheduler behavior...

9 years agonodestack: bugfix - reset backtracking points on diverging paths
Brian Norris [Sat, 23 Feb 2013 03:01:13 +0000 (19:01 -0800)]
nodestack: bugfix - reset backtracking points on diverging paths

Any time we diverge to a new execution path, we should reset the
backtracking information (i.e., which threads have executed and which
still must be backtracked) for the last node in the stack. We cannot
retain the "explored children" state after we have performed different
read-from or future-value divergence in the same node.

9 years agomodel: bugfix - inherit future values from previous loads
Brian Norris [Sat, 23 Feb 2013 00:39:54 +0000 (16:39 -0800)]
model: bugfix - inherit future values from previous loads

Once a future value is observed once, it should be available for
observation by other loads. Previously, we assume that a future value
will be passed to each load that may observe it. However, as
exemplified in the double-read-fv.c test, this may not be possible when
there are no other feasible stores from which to read.

Thus, when building an initial 'may-read-from' set, we should build a
set of inherited future values as well.

9 years agonodestack: don't use C++ references
Brian Norris [Sat, 23 Feb 2013 00:34:37 +0000 (16:34 -0800)]
nodestack: don't use C++ references

Just pass-by-value, since the reference can obfuscate the lifetime of,
for example, an automatic variable.

9 years agomodel: correct the "no valid reads" assertion
Brian Norris [Sat, 23 Feb 2013 00:12:34 +0000 (16:12 -0800)]
model: correct the "no valid reads" assertion

There are "no valid reads" only if there are no valid prior reads-from
candidates AND no potential values.

9 years agopromise: stash the whole future_value
Brian Norris [Sat, 23 Feb 2013 00:04:51 +0000 (16:04 -0800)]
promise: stash the whole future_value

We may need to generate a new Promise from the same future_value, so
stash the whole struct and expose it via get_fv().

9 years agotest: fences: add simple, semi-useful fence tests
Brian Norris [Fri, 22 Feb 2013 07:18:18 +0000 (23:18 -0800)]
test: fences: add simple, semi-useful fence tests

Note that due to the quirks discovered in double-read-fv, we don't see
all the expected behaviors in the fences2 test.

9 years agotest: add double-read-fv
Brian Norris [Fri, 22 Feb 2013 07:17:21 +0000 (23:17 -0800)]
test: add double-read-fv

This test fails (!) because we never see r1 = r2 = 42.

9 years agoaction: backtrack/sleep-sets for seq-cst fences
Brian Norris [Fri, 22 Feb 2013 17:42:00 +0000 (09:42 -0800)]
action: backtrack/sleep-sets for seq-cst fences

We now backtrack (and wake up sleep-set actions) on all pairs of seq-cst
operations such that at least one of the operations is a write or fence.

9 years agomodel: wake up pending (sleep-set) actions for fences
Brian Norris [Fri, 22 Feb 2013 07:07:55 +0000 (23:07 -0800)]
model: wake up pending (sleep-set) actions for fences

This completes fence backtracking properly by waking up actions when the
appropriate fence interactions occur. This is a little more complicated
than the simple "could_synchronize()" test, since fence synchronization
can involve interaction of more than two actions.

So, pull the complexity of the "should we wake a thread up" computation
into its own function.

9 years agomodel: only backtrack fences when acquire is before release
Brian Norris [Thu, 21 Feb 2013 19:59:50 +0000 (11:59 -0800)]
model: only backtrack fences when acquire is before release

Because there are up to 4 actions involved in this search for a
"conflict" (load, fence-acquire, fence-release, store), I overlooked the
fact that we only need to backtrack when the release comes after acquire
in the execution order. This fix skips past the 'release' action before
we begin searching for the 'acquire'.

9 years agomodel: document get_last{,_fence}_conflict()
Brian Norris [Wed, 20 Feb 2013 22:58:21 +0000 (14:58 -0800)]
model: document get_last{,_fence}_conflict()

9 years agomodel: schedule appropriate fence backtracking points
Brian Norris [Wed, 20 Feb 2013 02:28:41 +0000 (18:28 -0800)]
model: schedule appropriate fence backtracking points

This patch calculates the most recent backtracking point which may be a
fence. We require a separate function for computing this because a fence
"conflict" is much different than other conflicts; fences do not have a
memory location, but instead, they trigger release/acquire backtracking
in the presence of other stores/loads.

Left out of this patch:
(1) Sleep-set waking: even if we backtrack, we don't yet wake up our
    thread properly, yielding a "redundant" trace instead of a
    productive one
(2) memory_order_seq_cst: I have yet to determine how (if at all) we
    need to add additional backtracking in the presence of seq_cst
    fences
(3) documentation: need to describe get_last_fence_conflict() better

9 years agomodel: convert while-loops to for-loops
Brian Norris [Thu, 21 Feb 2013 00:27:45 +0000 (16:27 -0800)]
model: convert while-loops to for-loops

Make the loop-termination condition more clear.

9 years agomodel: add 'const'
Brian Norris [Wed, 20 Feb 2013 02:03:56 +0000 (18:03 -0800)]
model: add 'const'

9 years agoinclude: fixup header inclusion
Brian Norris [Wed, 20 Feb 2013 23:03:24 +0000 (15:03 -0800)]
include: fixup header inclusion

9 years agodon't include action.h from model.h
Brian Norris [Wed, 20 Feb 2013 07:37:12 +0000 (23:37 -0800)]
don't include action.h from model.h

9 years agomodel/action: move action_list_t to model.h
Brian Norris [Wed, 20 Feb 2013 07:30:31 +0000 (23:30 -0800)]
model/action: move action_list_t to model.h

action_list_t is only used by the ModelChecker class

9 years agopromise: move constructor out of header
Brian Norris [Wed, 20 Feb 2013 07:29:42 +0000 (23:29 -0800)]
promise: move constructor out of header

9 years agoscheduler: refactor round-robin loop
Brian Norris [Sat, 16 Feb 2013 02:22:49 +0000 (18:22 -0800)]
scheduler: refactor round-robin loop

This is the same computation, represented more clearly as a for loop
which, if it reaches the completion condition, means that it did not
find an enabled thread.

9 years agomodel: end-of-execution print
Brian Norris [Sat, 16 Feb 2013 02:09:03 +0000 (18:09 -0800)]
model: end-of-execution print

For readability of a "verbose" execution log (and even for the shorter,
non-verbose log), it helps to visually separate the final statistics
from any previously-printed statistics. For instance, in the following
verbose snippet from the end of an execution history, it's confusing why
there are two identical copies of the statistics:

... <other execution history> ...
Number of complete, bug-free executions: 4
Number of redundant executions: 0
Number of buggy executions: 0
Number of infeasible executions: 5
Total executions: 9
Total nodes created: 48

Execution 9:
---------------------------------------------------------------------
... <snipped trace info> ...
---------------------------------------------------------------------

Number of complete, bug-free executions: 4
Number of redundant executions: 0
Number of buggy executions: 0
Number of infeasible executions: 5
Total executions: 9
Total nodes created: 48

9 years agomodel: improve get_next_thread() comments
Brian Norris [Sat, 16 Feb 2013 02:08:09 +0000 (18:08 -0800)]
model: improve get_next_thread() comments

It's curious that get_next_thread() needs the current ModelAction as a
parameter. It helps to clarify that this argument is somwhat "optional."

9 years agoschedule: simplify Scheduler::select_next_thread()
Brian Norris [Fri, 15 Feb 2013 23:53:13 +0000 (15:53 -0800)]
schedule: simplify Scheduler::select_next_thread()

Now that the "select next thread" vs. "set_current_thread" is clear, we
don't actually need to set the value of 'current' in
select_next_thread().

9 years agomodel: pull scheduler's thread selection into get_next_thread()
Brian Norris [Fri, 15 Feb 2013 23:42:14 +0000 (15:42 -0800)]
model: pull scheduler's thread selection into get_next_thread()

The code makes more logical sense if ModelChecker::get_next_thread()
handles all of the thread selection decisions.

9 years agoschedule: split Scheduler::next_thread() into separate functions
Brian Norris [Fri, 15 Feb 2013 23:33:11 +0000 (15:33 -0800)]
schedule: split Scheduler::next_thread() into separate functions

next_thread() is basically overloaded to perform two different
functions, depending on the parameters. In one case, a caller might pass
a NULL thread, which meant that Scheduler is free to select its own next
thread. In another case, a caller will pass a non-NULL thread, which
meant that the caller is simply informing the Scheduler of the next
thread to execute (i.e., which one is "currently running").

These separate functionalities are now separate functions:

  Scheduler::select_next_thread()
  Scheduler::set_current_thread(Thread *)

9 years agomodel: factor out a 'switch_from_master()' function
Brian Norris [Fri, 15 Feb 2013 23:19:45 +0000 (15:19 -0800)]
model: factor out a 'switch_from_master()' function

This snippet of code is important and somewhat subtle. Although we only
use it once, let's make it a function to give it a higher-level
abstraction.

9 years agomodel: rework the release sequence fixups
Brian Norris [Fri, 15 Feb 2013 20:54:25 +0000 (12:54 -0800)]
model: rework the release sequence fixups

It makes more sense to pull the release sequence fixups out of the main
execution loop and only perform them after all other actions are
complete.

There's still some more cleanup to be done here, but it appears that
end-of-execution release sequence fixups are functional again.

9 years agomodel: simple refactoring
Brian Norris [Fri, 15 Feb 2013 20:17:06 +0000 (12:17 -0800)]
model: simple refactoring

This condition is useless. We can just return next_thrd directly.

9 years agomodel/threads: add documentation comments
Brian Norris [Fri, 15 Feb 2013 19:54:11 +0000 (11:54 -0800)]
model/threads: add documentation comments

Document {get,set}_pending(), has_asserted()/set_assert(), etc.

9 years agomodel: fix leaking "pending actions"
Brian Norris [Fri, 15 Feb 2013 19:02:05 +0000 (11:02 -0800)]
model: fix leaking "pending actions"

ModelActions that are "pending" for each thread are not automatically
freed when we rollback; we keep most of the active ModelActions on the
NodeStack, then we free them from there when we explore a new branch of
the state space.

This fix causes all the pending actions to be freed on any rollback.
This is safe for now, since we always roll back to the beginning of the
execution. If we roll back to an intermediate point, though, we need to
retain those pending actions which were also pending before the rollback
point. Hence the FIXME notice included in reset_to_initial_state().

9 years agomodel: add 'pending' assertion
Brian Norris [Wed, 13 Feb 2013 02:12:17 +0000 (18:12 -0800)]
model: add 'pending' assertion

We don't want to clobber a pending action.

9 years agomodel: stash all pending actions immediately
Brian Norris [Wed, 13 Feb 2013 01:56:13 +0000 (17:56 -0800)]
model: stash all pending actions immediately

9 years agomodel: pull 'has_asserted()' check out of take_step()
Brian Norris [Wed, 13 Feb 2013 01:24:31 +0000 (17:24 -0800)]
model: pull 'has_asserted()' check out of take_step()

Checks for mid-execution assertions should occur before take_step().
This can catch a mid-step bug (e.g., data race or user-assertion) that
happens between ModelAction steps.

9 years agothreads: bugfix - do not call thread_current() from model-checker
Brian Norris [Wed, 13 Feb 2013 00:54:38 +0000 (16:54 -0800)]
threads: bugfix - do not call thread_current() from model-checker

thread_current() was designed for use in the user context. It is not
guaranteed to provide a reliable result in the model-checker context,
since we may perform context switches as needed, such that the "last
executed user thread" may not be the thread that we are checking at the
time.

This change is made to clear up future changes that will modify the
scheduling patterns.

9 years agomodel: stash actions in each thread
Brian Norris [Wed, 13 Feb 2013 00:39:33 +0000 (16:39 -0800)]
model: stash actions in each thread

We don't want a global 'current_action' for saving the next action to
run; we want to stash the 'current action' for each thread. So just use
the 'pending' action in each Thread.

Note that this kinda breaks sleep sets for now. We'll have to redo this.

9 years agomodel: return next thread from take_step()
Brian Norris [Wed, 13 Feb 2013 00:33:40 +0000 (16:33 -0800)]
model: return next thread from take_step()

Note that this intentionally breaks release sequence fixups for now.

9 years agothreads/model: allocate Thread from w/in ModelChecker
Brian Norris [Wed, 19 Dec 2012 01:46:40 +0000 (17:46 -0800)]
threads/model: allocate Thread from w/in ModelChecker

It adds scheduling difficulties if we allocate/schedule a Thread from
the user-context (i.e., directly from the thrd_create() interface)
because then it is not necessarily atomic. For example, if we run a
thread up to its context switch for a THREAD_CREATE then switch to
another thread before the THREAD_CREATE is processed, then we will
already have constructed a Thread from the first thread (and prepared it
for scheduling) without processing it in the ModelChecker appropriately.
For instance, the following schedule might appear, causing problems:

 TID    ACTION
 ---    ------
    ...
  1     ATOMIC_READ         <--- Next action is THREAD_CREATE
 (1)    (construct Thread 3)
 (1)    (prepare new Thread for Scheduling)
  2     ATOMIC_READ
  3     THREAD_START        <--- Before its CREATE event??
  1     THREAD_CREATE

Note that this scheduling does not yet happen, as we always execute
the "lead-in" to THREAD_CREATE atomically. This may change, though.

9 years agoschedule: assert that model-checker thread doesn't enter scheduler
Brian Norris [Thu, 14 Feb 2013 20:23:48 +0000 (12:23 -0800)]
schedule: assert that model-checker thread doesn't enter scheduler

9 years agomodel: set thread state during 'swap' calls
Brian Norris [Tue, 12 Feb 2013 20:53:20 +0000 (12:53 -0800)]
model: set thread state during 'swap' calls

Rather than setting thread-state from subtle places within ModelChecker,
it makes more logical sense to set it from withing the Thread::swap
functions.

9 years agoMerge branch 'fences'
Brian Norris [Tue, 12 Feb 2013 19:48:41 +0000 (11:48 -0800)]
Merge branch 'fences'

9 years agopromise: use id_to_int()
Brian Norris [Tue, 12 Feb 2013 19:35:45 +0000 (11:35 -0800)]
promise: use id_to_int()

9 years agomodel: prune may-read-from set early
Brian Norris [Tue, 12 Feb 2013 18:42:17 +0000 (10:42 -0800)]
model: prune may-read-from set early

It helps to prune the may-read-from set (according to modification order
constraints) as we build it. This prevents unnecessary backtracking and
provides a significant (linear) speedup in model-checking speed.

Note that this now allows us to assume that at any point in an
execution, any selection from the may-read-from set is feasible.

9 years agoaction: bugfix - initialize member
Brian Norris [Tue, 12 Feb 2013 18:26:10 +0000 (10:26 -0800)]
action: bugfix - initialize member

9 years agomodel: rewrite mo_check_promises
Brian Norris [Sat, 9 Feb 2013 01:08:47 +0000 (17:08 -0800)]
model: rewrite mo_check_promises

Rather than use some special logic that was devised when we didn't
include promises in the mo-graph, we can simplify our mo_check_promises
code by querying the mo-graph for reachability. This *should* be at
least as good of a 'check' as the previous code, and much less cryptic.

9 years agomodel: remove argument from mo_check_promises
Brian Norris [Sat, 9 Feb 2013 01:08:33 +0000 (17:08 -0800)]
model: remove argument from mo_check_promises

9 years agocyclegraph: possible optimization
Brian Norris [Sat, 9 Feb 2013 00:34:33 +0000 (16:34 -0800)]
cyclegraph: possible optimization

9 years agomodel: rename according to the comments
Brian Norris [Fri, 8 Feb 2013 23:23:41 +0000 (15:23 -0800)]
model: rename according to the comments

The documentation mentions 'pread' and 'pwrite'. Those names aren't
actually used in the code, though, so change that.

9 years agomodel: add read-write coherence for promise nodes
Brian Norris [Thu, 7 Feb 2013 00:39:52 +0000 (16:39 -0800)]
model: add read-write coherence for promise nodes

Promises must be ordered after any other loads from the same thread.

9 years agopromise: update comments/names to reflect usage
Brian Norris [Thu, 7 Feb 2013 00:51:12 +0000 (16:51 -0800)]
promise: update comments/names to reflect usage

is_compatible() and is_compatible_exclusive() do not require a store as
an argument; they can just as well use a load

9 years agocyclegraph: expand template usage
Brian Norris [Thu, 7 Feb 2013 00:39:15 +0000 (16:39 -0800)]
cyclegraph: expand template usage

checkReachable() and addEdge() will be used in more forms. Add template
instantiations.

9 years agomodel: refactor to use a helper function
Brian Norris [Wed, 6 Feb 2013 23:46:23 +0000 (15:46 -0800)]
model: refactor to use a helper function

9 years agocyclegraph: don't delete promise nodes
Brian Norris [Wed, 6 Feb 2013 22:46:21 +0000 (14:46 -0800)]
cyclegraph: don't delete promise nodes

Merging can fail partway, leaving a somewhat inconsistent graph. This is
safe, since an inconsistent graph must be discarded as infeasible. But
this is a problem when dumping the modification order graph, since we
may dereference freed nodes. So for now, just don't free them.

9 years agocyclegraph: fixup support for dumping the modification order graph
Brian Norris [Wed, 6 Feb 2013 22:43:39 +0000 (14:43 -0800)]
cyclegraph: fixup support for dumping the modification order graph

We need to include promises in the modification order graph if we plan
on dumping it to a .dot file. This hacks it together so that it works
for now.

9 years agocyclegraph: mergeNodes(): return early if we violate RMW
Brian Norris [Wed, 6 Feb 2013 22:42:00 +0000 (14:42 -0800)]
cyclegraph: mergeNodes(): return early if we violate RMW

To be consistent, and to prevent unecessary merging work, we should
simply return from the mergeNodes() function as soon as we know it has
failed.

9 years agocyclegraph: refactor for indentation
Brian Norris [Wed, 6 Feb 2013 22:41:12 +0000 (14:41 -0800)]
cyclegraph: refactor for indentation

9 years agoMakefile / git: cleanup generated .dot and .pdf files
Brian Norris [Wed, 6 Feb 2013 22:00:05 +0000 (14:00 -0800)]
Makefile / git: cleanup generated .dot and .pdf files

9 years agocyclegraph: add wrappers for some common functionality
Brian Norris [Wed, 6 Feb 2013 02:27:35 +0000 (18:27 -0800)]
cyclegraph: add wrappers for some common functionality

9 years agomodel: fully utilize Promise nodes in CycleGraph
Brian Norris [Wed, 6 Feb 2013 01:45:31 +0000 (17:45 -0800)]
model: fully utilize Promise nodes in CycleGraph

We can eliminate the post-promise-resolution computations now that
mo_graph is built up to include Promise nodes.

9 years agomodel: cosmetic improvements to resolve_promises()
Brian Norris [Wed, 6 Feb 2013 01:39:36 +0000 (17:39 -0800)]
model: cosmetic improvements to resolve_promises()

Rename 'resolved' to 'haveResolved', since we will use the 'resolved'
name for something else.

9 years agocyclegraph: move function definitions out of header
Brian Norris [Wed, 6 Feb 2013 01:36:05 +0000 (17:36 -0800)]
cyclegraph: move function definitions out of header

I found out how to instantiate these functions from within the
implementation file (rather than the header). I can specifically list
those implementations that I want available.

9 years agocyclegraph: template-ize addRMWEdge()
Brian Norris [Wed, 6 Feb 2013 01:13:28 +0000 (17:13 -0800)]
cyclegraph: template-ize addRMWEdge()

9 years agocyclegraph: bugfix - pop edges properly
Brian Norris [Tue, 5 Feb 2013 22:26:24 +0000 (14:26 -0800)]
cyclegraph: bugfix - pop edges properly

Now that CycleNode's have back-edges, we need to properly remove *both*
the forward and back edges when doing roll-back.

9 years agomodel: add write-to-promise edges
Brian Norris [Tue, 5 Feb 2013 22:10:06 +0000 (14:10 -0800)]
model: add write-to-promise edges

Assume that any time a promise exists, is compatible with a store, and
is exclusive to the same thread as the store, that it is mod-ordered
after that store. This should never produce cycles, until we decide to
begin satisfying promises. At that point, if there's a cycle, then we
must either merge nodes (i.e., the store must satisfy that promise) or
else we discard the execution for the moment and perform the
satisfaction at a later point in the search space.

9 years agopromise: add is_compatible_exclusive()
Brian Norris [Tue, 5 Feb 2013 22:03:28 +0000 (14:03 -0800)]
promise: add is_compatible_exclusive()

Check if a Promise is both compatible *and* exclusive to a particular
thread. This allows ordering optimizations when we can guarantee that a
particular thread must fulfill the promise.

9 years agopromise: add const
Brian Norris [Tue, 5 Feb 2013 22:01:34 +0000 (14:01 -0800)]
promise: add const

9 years agomodel: utilize CycleGraph 'addEdge()' status
Brian Norris [Tue, 5 Feb 2013 21:47:20 +0000 (13:47 -0800)]
model: utilize CycleGraph 'addEdge()' status

The mo_graph is only modified if addEdge() returns true. Utilize this
information.

9 years agocyclegraph: return 'added' status for addEdge()
Brian Norris [Tue, 5 Feb 2013 21:44:32 +0000 (13:44 -0800)]
cyclegraph: return 'added' status for addEdge()

The ModelChecker would like to know if it's adding a new edge, or just
and existing edge. If the edge is not new, then there are fewer
resulting update checks needed.

9 years agocyclegraph: add documentation
Brian Norris [Tue, 5 Feb 2013 06:50:45 +0000 (22:50 -0800)]
cyclegraph: add documentation

9 years agocyclegraph: bugfix - only use concrete writes to eliminate threads
Brian Norris [Tue, 5 Feb 2013 01:12:11 +0000 (17:12 -0800)]
cyclegraph: bugfix - only use concrete writes to eliminate threads

9 years agocyclegraph: edit template for checkReachable
Brian Norris [Tue, 5 Feb 2013 00:24:36 +0000 (16:24 -0800)]
cyclegraph: edit template for checkReachable

9 years agocyclegraph: edit template for addEdge
Brian Norris [Tue, 5 Feb 2013 00:24:21 +0000 (16:24 -0800)]
cyclegraph: edit template for addEdge

9 years agocyclegraph: add overloaded getNode_noCreate()
Brian Norris [Tue, 5 Feb 2013 00:22:03 +0000 (16:22 -0800)]
cyclegraph: add overloaded getNode_noCreate()

Need a generic way to map a ModelAction/Promise to a CycleNode.

9 years agomodel: add promise-node edges for 'read' actions
Brian Norris [Sat, 2 Feb 2013 01:51:56 +0000 (17:51 -0800)]
model: add promise-node edges for 'read' actions

9 years agocyclegraph: template-ize checkReachable()
Brian Norris [Sat, 2 Feb 2013 01:47:57 +0000 (17:47 -0800)]
cyclegraph: template-ize checkReachable()

ModelChecker will need to query the mo_graph regarding the modification
order of promised future writes.

9 years agomodel: template-ize 'r_modification_order'
Brian Norris [Sat, 2 Feb 2013 00:44:22 +0000 (16:44 -0800)]
model: template-ize 'r_modification_order'

We will need to add "read modification order" edges when 'rf' is either
a ModelAction or a Promise. This function works nicely with a template.

9 years agoaction: fixup printing for RMW/RMWR
Brian Norris [Fri, 1 Feb 2013 23:33:38 +0000 (15:33 -0800)]
action: fixup printing for RMW/RMWR

Some read actions didn't really have a correct 'value' saved in the
ModelAction. Now that we have the 'promise' recorded, always retrieve
the value from reads_from or reads_from_promise.