Crate wasmtime_internal_unwinder 

Wasmtime unwinder.

⚠️ Warning ⚠️: this crate is an internal-only crate for the Wasmtime project and is not intended for general use. APIs are not strictly reviewed for safety and usage outside of Wasmtime may have bugs. If you’re interested in using this feel free to file an issue on the Wasmtime repository to start a discussion about doing so, but otherwise be aware that your usage of this crate is not supported.

wasmtime-unwinder

This crate implements an unwind info format, stack walking, and unwinding for Wasmtime. It includes logic that:

• Can walk the Wasmstack and visit each frame;
• Can find exception handlers using an efficient format serialized from Cranelift compilation metadata that can be mapped and used in-place from disk;
• Provides a “throw” helper that, when called from host code that has been invoked from Wasmcode, can find a handler; and a “resume” stub that can be invoked to transfer control to the corresponding handler.

Structs

ExceptionHandler

Wasmtime exception table item, after parsing.

ExceptionTable

ExceptionTable deserialized from a serialized slice.

Frame

A stack frame within a Wasm stack trace.

FrameCursor

A cursor over Frames in a single activation of Wasm.

Handler

Description of a frame on the stack that is ready to catch an exception.

UnwindHost

If we have the above host-specific implementations, we can implement Unwind.

Traits

Unwind

Implementation necessary to unwind the stack, used by Backtrace.

Functions

frame_iterator^⚠

Wrap FrameCursor in a true iterator.

get_stack_pointer

Get the current stack pointer (at the time this function is executing). This may be used to check, e.g., approximate space remaining on a stack, but cannot be relied upon for anything exact because the stack pointer from within this function is read and the frame is later popped.

visit_frames^⚠

Walk through a contiguous sequence of Wasm frames starting with the frame at the given PC and FP and ending at trampoline_fp. This FP should correspond to that of a trampoline that was used to enter the Wasm code.