Optimizing Bytecode-to-Source Mapping for Virtual Machines

Optimizing Bytecode-to-Source Mapping for Virtual Machines

While working through Crafting Interpreters, I explored efficient ways to map bytecode offsets back to source lines. I compared storing a line number per byte against run-length encoding and starting offsets. The analysis reveals how binary search and cursor-based traversal offer different trade-offs between memory usage and lookup speed, mirroring strategies used by the JVM and Lua.

The beauty is we're not forced to choose between binary search and the cursor approach. We can choose either one depending on the scenario.

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2026-07-27