Handle reentrant host calls #60
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…ave/restore instruction pointer, and preserve results Detect nested CreateInvoker calls by checking the operand stack height. Save the current instruction pointer for nested calls and restore it on success or exceptions instead of unconditionally flushing the call stack. For nested calls push results back onto the operand stack so callers can consume them; for top-level calls keep the previous behavior of clearing remaining stack values.
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Pull Request Overview
This PR implements support for nested function calls in the WebAssembly runtime by introducing special handling to distinguish between top-level and nested function invocations.
- Adds nested call detection based on operand stack state
- Preserves and restores instruction pointer for nested calls
- Implements different cleanup strategies for top-level vs. nested calls
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Co-authored-by: Copilot <[email protected]>
Co-authored-by: Copilot <[email protected]>
Co-authored-by: Copilot <[email protected]>
kelnishi
approved these changes
Nov 3, 2025
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This fixes an issue I found where a host function calling back into WASM would cause the stack to get into an unrecoverable state.
Detect nested calls via operand stack, save/restore instruction pointer, and preserve results.
Detect nested CreateInvoker calls by checking the operand stack height. Save the current instruction pointer for nested calls and restore it on success or exceptions instead of unconditionally flushing the call stack. For nested calls push results back onto the operand stack so callers can consume them; for top-level calls keep the previous behavior of clearing remaining stack values.