Skipping NOPs After BR Table Operations in wasm_loader_find_block_addr

[MartinMichelis]

Hello,

We have been reviewing the wasm_loader_find_block_addr function in wasm_mini_loader.c and noticed specific behavior for the cases WASM_OP_BR_TABLE in line 3586 and EXT_OP_BR_TABLE_CACHE in line 3599.

In these cases, the code first skips a LEB number, and then proceeds to skip the NOP operations following the BR table operation.

We have 2 questions regarding this implementation:

1. Why do we skip NOPs after BR table operations but not after other operations?

2. Is there a maximum number of NOPs allowed after a BR table operation? We are particularly interested in understanding if there’s an upper bound on the loop that skips these NOPs.

Any clarification on the reasoning or constraints behind this behavior would be greatly appreciated.

Thank you!