Abstract: Based on replay of a thread, one implementation observes an influx of a value of a memory cell comprising an interaction between the thread and the value of the memory cell at an execution time point in the replaying, and determines whether the value of the memory cell observed from the influx is inconsistent with a prior value of the memory cell as known by the thread at the execution time point. If so, this implementation initiates an indication of a data inconsistency. Based on replay of a plurality of threads, another implementation identifies a memory cell that was accessed by a first thread while a thread synchronization mechanism was active on the first thread. Then, if there was another access to the memory cell by a second thread without use of the thread synchronization mechanism, this implementation initiates an indication of a potential data contention.

Abstract: Based on replay of a thread, one implementation observes an influx of a value of a memory cell comprising an interaction between the thread and the value of the memory cell at an execution time point in the replaying, and determines whether the value of the memory cell observed from the influx is inconsistent with a prior value of the memory cell as known by the thread at the execution time point. If so, this implementation initiates an indication of a data inconsistency. Based on replay of a plurality of threads, another implementation identifies a memory cell that was accessed by a first thread while a thread synchronization mechanism was active on the first thread. Then, if there was another access to the memory cell by a second thread without use of the thread synchronization mechanism, this implementation initiates an indication of a potential data contention.

Abstract: Identifying and reporting potential data inconsistencies and/or potential data contentions based on historic debugging traces. Based on replay of a thread, some implementations observe an influx of a value to a memory cell, and determine whether the value of the memory cell observed from the influx is inconsistent with a prior value of the memory cell as known by the thread. If so, these implementations can initiate an indication of a data inconsistency. Based on replay of a plurality of threads, other implementations identify a memory cell that was accessed by a first thread while a thread synchronization mechanism was active on the first thread. Then, if there was another access to the memory cell by a second thread without use of the thread synchronization mechanism, these implementations might initiate an indication of a potential data contention.

Abstract: Identifying and reporting potential data inconsistencies and/or potential data contentions based on historic debugging traces. Based on replay of a thread, some implementations observe an influx of a value to a memory cell, and determine whether the value of the memory cell observed from the influx is inconsistent with a prior value of the memory cell as known by the thread. If so, these implementations can initiate an indication of a data inconsistency. Based on replay of a plurality of threads, other implementations identify a memory cell that was accessed by a first thread while a thread synchronization mechanism was active on the first thread. Then, if there was another access to the memory cell by a second thread without use of the thread synchronization mechanism, these implementations might initiate an indication of a potential data contention.

Abstract: Presenting historical state of a code element of a prior execution of an entity. An embodiment includes presenting historical state of the code element based on replaying segment(s) of the prior execution from trace data. Presenting the historical state includes presenting a first state of the code element, in connection with a first execution time point. The first state is based on a first memory access for the code element at the first execution time point. Presenting the historical state also includes presenting the first state of the code element along with an indication that the first state is a last known state (in connection with a subsequent execution time point) or a next known state (in connection with a prior execution time point).

Abstract: Querying resource lifetime using a trace of program execution. An embodiment includes identifying a query expression targeted at least a portion of the trace of program execution. The query expression specifies at least (i) a data object representing a plurality of events identified in the trace, each event associated with one or more attributes relating to resource lifetime, and (ii) one or more conditions matching the one attributes relating to resource lifetime. In response to receiving the query expression, the query expression is processed based at least on an analysis of an identified subset of the trace. Based on processing the query expression, a result data set that includes or identifies at least one of the plurality of events that meets the one or more conditions is presented.

Abstract: Querying resource lifetime using a trace of program execution. An embodiment includes identifying a query expression targeted at least a portion of the trace of program execution. The query expression specifies at least (i) a data object representing a plurality of events identified in the trace, each event associated with one or more attributes relating to resource lifetime, and (ii) one or more conditions matching the one attributes relating to resource lifetime. In response to receiving the query expression, the query expression is processed based at least on an analysis of an identified subset of the trace. Based on processing the query expression, a result data set that includes or identifies at least one of the plurality of events that meets the one or more conditions is presented.

Abstract: Querying resource lifetime using a trace of program execution. An embodiment includes identifying a query expression targeted at least a portion of the trace of program execution. The query expression specifies at least (i) a data object representing a plurality of events identified in the trace, each event associated with one or more attributes relating to resource lifetime, and (ii) one or more conditions matching the one attributes relating to resource lifetime. In response to receiving the query expression, the query expression is processed based at least on an analysis of an identified subset of the trace. Based on processing the query expression, a result data set that includes or identifies at least one of the plurality of events that meets the one or more conditions is presented.

Abstract: Performing a query over a trace of program execution. A method includes receiving a query expression targeted at least a portion of a trace of program execution. A data structure that represents the query expression is built. The data structure has a plurality of data elements representing concepts and operations of the query. Based on the data structure, an order for evaluating the data elements is identified. The plurality of data elements is evaluated. Based on the evaluation, at least a portion of a result set is conveyed for consumption.

Abstract: A method and system for applying an appropriate object ownership model is provided. In a preferred embodiment, an operating system selectively applies an object ownership model with which running programs are compatible. This permits programs designed to be used with operating systems that do not apply a rigorous object ownership model to be used with an operating system capable of applying a rigorous object ownership model. The method and system has both an automatic object deallocation phase and an object access control phase. In the automatic deallocation control phase, the method and system defers the automatic deallocation of objects owned by programs that are incompatible with automatic object deallocation until a later time at which no such programs are still running. Instead of immediately deallocating the objects owned by a terminating program, the method and system designates them for deferred deallocation.