Using gdb with asyncify

[rennergade]

As of now if we apply asyncify it disables our ability to use gdb.

I think the problem is similar to this issue: WebAssembly/binaryen#3462

I inquired about any updates that may help us.

[rennergade]

It seems like this older PR enabled DWARF info, I wonder if using this would make this work for us:

WebAssembly/binaryen#2520

[rennergade]

Got a response here: WebAssembly/binaryen#3462 (comment)

It looks like it may be pretty difficult to use gdb or anything depending on DWARF.

I looked into using lldb which may be a useful alternative.

[rennergade]

I was able to run lldb on hello world with the following:

apt install lldb

changed debug line to:
lldb -- $wasmtime_base/target/debug/wasmtime run -D debug-info -O opt-level=0 --wasi threads=y --wasi preview2=n [target]

and had to set aslr off once running:
settings set target.disable-aslr false

@qianxichen233 or @yzhang71 can one of you test this method on something more complicated that uses asyncify?

[qianxichen233]

I just tried lldb with write.wasm (with asyncify applied), unfortunately it gives the error when I tried to break into user program's main function Error: failed to emit DWARF debug information

[qianxichen233]

another very minor issue on using gdb on lind-wasm, just also post here to see if we have a better solution on it:
Since all the pointers in user code is based on virtual address, not real sys address, when I try to print the string or other pointer based struct in gdb, I am not able to simply do p str since str is virtual address pointer. A work around is to manually add the base_address to the str and print it but I wonder if there is even simpler way to do it so I do not need to pull out the base address every time