AITracer
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package ai
Called when the analyzed method throws an exception that is not caught within the method.
Called when the analyzed method throws an exception that is not caught within
the method. I.e., the interpreter evaluates an athrow instruction or some
other instruction that throws an exception.
Called when the evaluation of a subroutine terminated abruptly due to an unhandled exception.
Called when the evaluation of a subroutine terminated abruptly due to an unhandled exception.
The subroutine that will be continued. The id is the pc of the first instruction of the subroutine. It is 0 if it is the method as such.
The number of subroutines that are terminated.
Called immediately before the abstract interpretation of the specified code is performed.
Called immediately before the abstract interpretation of the specified code is performed.
If the tracer changes the operandsArray and/or localsArray, it is
the responsibility of the tracer to ensure that the data structures are still
valid afterwards.
Called by the interpret when a local variable with the given index (lvIndex)
was set to a new value and, therefore, the reference stored in the local variable
previously was useless/dead.
Called by the domain if something noteworthy was determined.
Called by the domain if something noteworthy was determined.
The domain.
The class (typically the (partial) domain) that generated the message.
A String that identifies the message. This value must not be null,
but it can be the empty string.
The message; a non-null String that is formatted for the console.
Called by the framework if a constraint is established.
Called by the framework if a constraint is established. Constraints are generally established whenever a conditional jump is performed and the evaluation of the condition wasn't definitive. In this case a constraint will be established for each branch. In general the constraint will be applied before the join of the stack and locals with the successor instruction is done.
Called by the interpreter after an instruction (currentPC) was evaluated and
before the instruction with the program counter targetPC may be evaluated.
Called by the interpreter after an instruction (currentPC) was evaluated and
before the instruction with the program counter targetPC may be evaluated.
This method is only called if the instruction with the program counter
targetPC will be evaluated in the future and was not yet scheduled.
I.e., when the abstract interpreter
determines that the evaluation of an instruction does not change the abstract
state (associated with the successor instruction) and, therefore, will not
schedule the successor instruction this method is not called.
In case of if or switch instructions flow may be
called multiple times (even with the same targetPC) before the method
instructionEvaluation is called again.
OPAL performs a depth-first exploration. However, subroutines are always first finished analyzing before an exception handler - that handles abrupt executions of the subroutine - is evaluated.
The set of initial locals computed when the method is interpreted for the first time.
Called before an instruction is evaluated.
Called before an instruction is evaluated.
This enables the tracer to precisely log the behavior of the abstract interpreter, but also enables the tracer to interrupt the evaluation to, e.g., enable stepping through a program.
The operand stack before the execution of the instruction.
The registers before the execution of the instruction.
Called by the abstract interpreter whenever two paths converge and the values on the operand stack and the registers are joined.
Called by the abstract interpreter whenever two paths converge and the values on the operand stack and the registers are joined.
The operand stack as it was used the last time when the instruction with the given program counter was evaluated.
The registers as they were used the last time when the instruction with the given program counter was evaluated.
The current operand stack when we re-reach the instruction
The current registers.
The result of joining the operand stacks and register assignment.
Called before a jump to a subroutine.
Called by the interpreter if a successor instruction is NOT scheduled, because the abstract state didn't change.
Called if the instruction with the targetPC was already scheduled.
Called if the instruction with the targetPC was already scheduled. I.e., the
instruction was already scheduled for evaluation, but is now moved to the first
position in the list of all instructions to be executed (related to the specific
subroutine). A rescheduled event is also issued if the instruction was the
the first in the list of instructions executed next.
However, further instructions may be appended to the list before the
next instructionEvaluation takes place.
OPAL performs a depth-first exploration.
Called when the abstract interpretation of a method has completed/was interrupted.
Called when a RET instruction is encountered.
Called when a RET instruction is encountered. (That does not necessary imply
that the evaluation of the subroutine as such has finished. It is possible
that other paths still need to be pursued.)
Called when the evaluation of a subroutine (JSR/RET) as a whole is completed.
Called when the evaluation of a subroutine (JSR/RET) as a whole is completed. I.e., all possible paths are analyzed and the fixpoint is reached.
Defines the interface between the abstract interpreter and a module for tracing and debugging the interpreter's progress. In general, a tracer is first registered with an abstract interpreter. After that, when a method is analyzed, the AI calls the tracer's methods at the respective points in time.
A tracer is registered with an abstract interpreter by creating a new subclass of AI and overriding the method AI.tracer.
All data structures passed to the tracer are the original data structures used by the abstract interpreter. Hence, if a value is mutated (e.g., for debugging purposes) it has to be guaranteed that the state remains meaningful. Hence, using the AITracer it is possible to develop a debugger for OPAL and to enable the user to perform certain mutations.