Notac

Allocator-dependence interpreter — in-browser demo PLDI 2026

Example

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Run A allocator null addr version

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Variables

Heap accessible inaccessible null read written cleared alloc'd

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Run B allocator null addr version

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Variables

Heap accessible inaccessible null read written cleared alloc'd

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Notac is a research interpreter for studying how memory allocator choice affects program semantics. The paper, “The Downgrading Semantics of Memory Safety” (PLDI 2026), introduces Gradual Allocator Independence (GAI): a memory-safety property whose intuition is that an allocator must not influence program execution other than (i) running out of memory in a checked manner, and (ii) casts of allocated pointers. The demo lets you inspect — side-by-side and step-by-step — how different allocators do (or do not) produce similar traces.