V9016

Code

V9016

Message

Container declares a call depth that exceeds the VM frame-stack buffer

The container’s declared worst-case call depth (FileHeader.max_call_depth) is larger than the call-frame buffer the embedder provided to the VM. VmReady::start rejects the container before any init code runs, so no PLC instructions execute.

Codegen computes max_call_depth from the program’s static call graph (longest path through CALL and user-FB_CALL edges, counting the entry frame). The VM compares that number against VmBuffers.frames.len().

To resolve:

• Grow the embedder’s frame buffer if the program legitimately needs the declared depth, then reload.

• Recompile with a shallower call chain.

The trap message reports both numbers (required and capacity). A required of 0 means the container was built without populating the field (legacy or hand-built containers); in that case no comparison runs and this trap is not raised.

Think IronPLC is wrong about this?

If you believe this diagnostic is incorrect, open an issue on GitHub with a small sample that demonstrates the problem.