Dirk Beyer and Matthias Dangl. Chaudhuri and A. Springer-Verlag, Heidelberg. Dirk Beyer. Chechik and J. Di Nitto, M. Harman, and P. Baier and C. Skip to content. Dismiss Join GitHub today GitHub is home to over 36 million developers working together to host and review code, manage projects, and build software together. Sign up. An Exchange Format for Verification Witnesses. Branch: master New pull request. Find File. Download ZIP. Sign in Sign up. Launching GitHub Desktop Go back. Launching Xcode Launching Visual Studio Latest commit cf29 Mar 23, Data Elements In order to represent the witness automaton in GraphML, the edges and nodes of the graph are enriched with XML data elements of different types.
Yes sourcecodelang Valid values: Currently, only C and Java are supported. The name of the programming language. Yes producer Valid values: Any The name of the tool that produced the witness automaton, e. Yes architecture Valid values: An identifier for the assumed architecture The architecture assumed for the verification task, e.
The date and time the witness was created in ISO format. The date must contain the year, the month, and the day, separated by dashes '-'. The date is separated from the time using the capital letter 'T'. The time must be given in hours, minutes, and seconds, separated by colons ':'. Only exactly one initial state entry state is allowed.
Yes Yes sink Valid values: false default or true This state is a sink. All paths that lead to this state end here and should not be further explored by the witness validator. Nodes where this flag is set must not have any leaving transitions Yes No violation Valid values: false default or true The witness claims that paths that reach this state violate the specification. A violation witness is only accepted if the witness validator detects a specification violation and the witness automaton is in a state where this flag is set.
Yes No invariant Valid values: A C expression that must evaluate to the C type int used as boolean and may consist of conjunctions or disjunctions, but not function calls.
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Local variables that have the same name as global variables or local variables of other functions can be qualified by using a data tag with the invariant. No Yes invariant. Due to scopes in C, there may be name conflicts. The witness validator will first look for a variable with a matching name in the scope of the provided function name before checking the global scope. This tag applies to the invariant as a whole. It is not possible to specify invariants about local variables of different functions.
There is currently no support for different variables with the same name within different scopes of the same function. Each of the expressions must evaluate to the C type int used as boolean and may not consist of function calls, conjunctions, or disjunctions. C expressions representing assumptions about the current state. Local variables that have the same name as global variables or local variables of other functions can be qualified by using the assumption.
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Yes No assumption. This tag applies to the assumption as a whole. It is not possible to specify assumptions about local variables of different functions. This tag applies to the assumption as a whole, it is therefore not possible to refer to multiple function-return values within the same transition. Otherwise, it is superfluous. Yes No control Valid values: condition-true or condition-false A branching in source code is always labeled with a condition, thus there are two branches: one that is taken if the condition evaluates to true, the other if it evaluates to false; this is represented by the values condition-true , respectively, condition-false.
An automaton transition is allowed if the current control-flow edge is a control-statement, e. Yes No startline Valid values: Valid line number of the program Each statement, or expression, on a control-flow edge was derived from a line or multiple lines - see endline in the source code. The startline corresponds to the line number on that a statement, or expression, of a control-flow edge started Yes Yes endline Valid values: Valid line number of the program A statement, or expression, can be written across multiple lines.
The value of endline represents the line number on that the statement, or expression, of a matching control-flow edge ends. Yes Yes startoffset Valid values: Offset of a specific character in the program from the program start. Matches the character offset on that the expression or statement represented by the control-flow edge starts.
It is important that witness consumer validator and witness producer agree on the encoding of the C program. Yes Yes endoffset Valid values: Offset of a specific character in the program from the program start. Matches the character offset on that the expression or statement represented by the control-flow edge ends. It is important that witness checker and witness producer agree on the encoding of the C program. Yes Yes enterLoopHead Valid values: false default or true Signifies that an witness-automaton transition annotated with this guard only matches if the observed analysis takes a control-flow edge into a loop head.
Yes Yes enterFunction Valid values: Function name The name of the function that is entered via this transition. Assuming a function stack, this pushes the function onto the stack. If you use this data node type, you also must use the type returnFromFunction. When assumption. The path is considered to stay in the specified function until another transition is annotated with this data node for another function or a transition annotated with returnFromFunction , telling the validator that the path continues in the previous function on the stack.
Assuming a function stack, this name must match the name of the function popped from the function stack. If you use this data node type, you also must use the type enterFunction. See enterFunction for more information. Yes Yes Tools may introduce their own data nodes with custom keys and values. This witness specification is a work in progress and will be subject to modifications.
Additional Edge Data for Concurrent Programs Validating concurrent programs is a complex task, because it is necessary to determine possible interleavings of thread operations and when a thread is started or exited. The following information should additionally be available in the witness: key Meaning Allowed in Violation Witnesses Allowed in Correctness Witnesses threadId Represents the currently active thread for the transition.
If no threadId is given, any thread can be active. The value should be a unique identififer for a thread. Yes Yes createThread The currently active thread value of threadId creates a new thread value of createThread.
In general, using a threadId is only allowed after creating a matching thread. The new thread's function can be entered on a second transition following this transition, such that the transition with the enterFunction key has the threadId of the created thread. When the function of the thread is exited, the thread is assumed to be terminated and its threadId should no longer be used.
Yes Yes CPAchecker partially supports the validation of violation witnesses for concurrent programs. Witnessing Program Termination Termination is a liveness property and, in contrast to safety properties, its violation cannot be witnessed by a finite number of program execution steps. Validating Witnesses using a Witness Validation Service The witness-validation service is designed to be as simple to use as possible. This service can also be used via the command line:. Running CPAchecker with default stack size k.
Specify a larger value with -stack if needed. Property violation WitnessAutomaton found by chosen configuration. More details about the verification run can be found in the directory ". The output of the command should look similar to the following:. Execution finished normally Writing output log to file Ultimate.
Using refinement for predicate analysis with PredicateAbstractionRefinementStrategy strategy. Writing a Violation Witness with Ultimate Automizer From the Ultimate Automizer directory, the following command will start Ultimate Automizer to verify a task for which it will come up with a feasible counterexample:.
Specify a larger value with -heap if you have more RAM. CPAchecker 1. No property violation found by chosen configuration. Producing Correctness Witnesses with Ultimate Automizer The procedure for producing a correctness witness with Ultimate Automizer does not differ from producing a violation witness. Validating Correctness Witnesses with CPAchecker For the validation, we assume that one of the previously obtained witnesses for the example task has been named correctness-witness.
Validating Correctness Witnesses with Ultimate Automizer Again, the procedure for validating a correctness witness with Ultimate Automizer does not differ from validating a violation witness. You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window. Oct 17, Example programs and witness files. Nov 9, Update hashes in example witnesses to SHA Jul 24, Initial commit. Oct 6, The harder the times, the deeper the winter, the greater the need to live in the presence of God.
And Janani Luwum, a normal human being, did that and stood against the government. He is what in the Christian tradition — particularly the tradition of the early centuries — is known as a red martyr: a martyr whose blood is shed. There is also — and perhaps something we will identify with more easily — white martyrdom from that tradition.
White martyrdom is the life that is so utterly dedicated to Christ that it takes — and is seen to take — visibly seriously those words from the gospel: that the seed must fall into the ground and die. It is the image of the person whose life is so surrendered that they speak of Christ in everything they do and say. In the Church of England today we have few red martyrs, but there are many white martyrs. They are found in so many parishes.
They are found in laity and clergy. They are found in the person who is always there when they are needed, and many of us will have someone in mind. They are found in the people who bear the brunt of what it is to be the Church of England today. Yet martyrdom — white and red — is above all an act of hope.
The Church of Uganda rose to new strength after Luwum. In the gospel reading Jesus gives a great shout of triumph, of expected victory, in defying the powers calling for his death, by affirming that in life and death the glory of God is our aim. That is where we come to: the glory of God. In our lives, the call to seek the glory of God overwrites even the call of life itself. In seeking God's glory we can do nothing for ourselves.
When our lives are surrendered it is God who can be trusted to take that offering and bring it to the glory of His name — and in so doing to offer life to all the world. In Luwum offering and dying, as with the other martyrs, the name of Christ is held high. We recalled that fact in our silence on the anniversary of the deaths of the Coptic martyrs. In that terrible and evil event just over a year ago, God used the force of evil to defeat evil.