From f92474f04a6e57df48c91a4c9e38f31cff153f39 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Wed, 5 Jun 2013 17:25:30 -0700 Subject: [PATCH] execution: remove redundant condition, reword doc for promises_may_allow promises_may_allow() doesn't actually need to check for promises.empty(), as the loop bounds take care of that. In the same spirit, we can reword the comments/documentation so that (1) it is not redundant (condition (a) is subsumed by (b)) (2) we are more explicit about what we actually mean by "crossing promises" --- execution.cc | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/execution.cc b/execution.cc index e04b672..53aa521 100644 --- a/execution.cc +++ b/execution.cc @@ -755,12 +755,13 @@ bool ModelExecution::process_mutex(ModelAction *curr) /** * @brief Check if the current pending promises allow a future value to be sent * - * If one of the following is true: - * (a) there are no pending promises - * (b) the reader and writer do not cross any promises - * Then, it is safe to pass a future value back now. + * It is unsafe to pass a future value back if there exists a pending promise Pr + * such that: * - * Otherwise, we must save the pending future value until (a) or (b) is true + * reader --exec-> Pr --exec-> writer + * + * If such Pr exists, we must save the pending future value until Pr is + * resolved. * * @param writer The operation which sends the future value. Must be a write. * @param reader The operation which will observe the value. Must be a read. @@ -769,8 +770,6 @@ bool ModelExecution::process_mutex(ModelAction *curr) bool ModelExecution::promises_may_allow(const ModelAction *writer, const ModelAction *reader) const { - if (promises.empty()) - return true; for (int i = promises.size() - 1; i >= 0; i--) { ModelAction *pr = promises[i]->get_reader(0); //reader is after promise...doesn't cross any promise -- 2.34.1