If I want to add new content to Claripy, is there a way not to modify its original code file?

[ShadowLL]

I want to add a load to represent the value loaded from memory, such as <Load (esp)>. Is there a suitable way to achieve this without changing the Claripy source code?

[ltfish]

Use Annotations to annotate a BVV or BVS.

[ShadowLL]

@ltfish Sorry, I do n’t quite understand what you mean, can you give an example? Thank you.

[ltfish]

class YourOwnAnnotation(claripy.Annotation):
    # all ASTs annotated by this annotation are values loaded from [esp]
    def __init__(self):
        pass

    def eliminatable(self):
        # return True or False based on your needs

    def relocatable(self):
        # return True or False based on your needs


value = state.memory.load(state.regs.esp, 4)
value = value.annotate(YourOwnAnnotation())
# now your value is annotated. you can access its annotations by value.annotations

[ltfish]

Here are some test cases in terms of how to use Annotations: https://github.com/angr/claripy/blob/master/tests/test_annotations.py

[ShadowLL]

@ltfish When performing an operation, will there be Annotation with elements in the operation result? For example, <BVS a> + <BVS b>, where <BVS a> has Annotation, then does the result have Annotation? I have observed before using it, in some cases the result will also have Annotation, in some cases it will not, what is the specific impact?

[ltfish]

then does the result have Annotation?

This is what relocatable is for. See angr API doc.

I have observed before using it, in some cases the result will also have Annotation, in some cases it will not, what is the specific impact?

It's probably a bug. I know that If() will cause a loss of annotations, and that's something that we have fixed in another branch. I just need to push the student to submit a PR for that.

[ShadowLL]

@ltfish Thank you for your patience.

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