This commit fixes the build errors in the unwind info implementation for
the x86 ABI by changing `byteorder` to build `no_std`.
This copies two simple functions from the `WriteBytesExt` trait so that
we can easily write to a `Vec<u8>` with a particular endianness.
Fixes#1203.
* Implement emitting Windows unwind information for fastcall functions.
This commit implements emitting Windows unwind information for x64 fastcall
calling convention functions.
The unwind information can be used to construct a Windows function table at
runtime for JIT'd code, enabling stack walking and unwinding by the operating
system.
* Address code review feedback.
This commit addresses code review feedback:
* Remove unnecessary unsafe code.
* Emit the unwind information always as little endian.
* Fix comments.
A dependency from cranelift-codegen to the byteorder crate was added.
The byteorder crate is a no-dependencies crate with a reasonable
abstraction for writing binary data for a specific endianness.
* Address code review feedback.
* Disable default features for the `byteorder` crate.
* Add a comment regarding the Windows ABI unwind code numerical values.
* Panic if we encounter a Windows function with a prologue greater than 256
bytes in size.