Fix tableidx overflow on call_indirect #303
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…EBUG/TRACE/WARN/INFO mode This way you get a friendly error when trying to figure out why something is not working instead of a vague segfault.
tolauwae
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Jan 28, 2025
tolauwae
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Feb 10, 2025
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On some programs, the vm can run into an error like this
Unsigned LEB at byte 0x12800b011 overflow. This overflow occurs when reading table indexes on thecall_indirectfunction. It occurs because the table index in WARDuino can at most consist of 7 or 1 bits (the maximum amount of bit differs in two parts of the vm). In the wasm specification however, the table index is specified to be a u32. You would expect this error to only occur on modules using multiple tables but as it turns out this also happens on rust binaries that use just a single table. The reason for this is that the rust compiler can sometimes use a 5 byte table index0x80 0x80 0x80 0x80 0x00to encode table index 0 as described in this blog post. Any binary using such an index will fail to execute, this PR fixes that.This PR also adds an error message for stack overflows during
setup_callwhen in debug/trace/warn/info mode. This way users attempting to run bigger programs will more quickly realize that they just need to increase the stack size (or run their program in release mode) and it's not an issue with the vm implementation.