wasm-opt: tables cannot be declared after functions

wasm-opt appears to expect tables in textual wast to be declared before any function bodies, but some utilities such as wabt's wasm2wast always places it after, near the bottom of the file.

[parse exception: no table]Fatal: error in parsing input

https://github.com/WebAssembly/binaryen/blob/b2c17a105e9fbe86c059793032ee0be676245a8a/src/wasm/wasm-s-parser.cpp#L1356

If I move the table text above the functions, the issue resolves.

 (module
   (type $t0 (func))
+  (table 1 anyfunc)
   (func $f0 (type $t0))
   (func $f1 (type $t0)
     (call_indirect $t0
       (i32.const 0)
     )
   )
-  (table 1 anyfunc)
   (elem (i32.const 0) $f0)
 )

I recall seeing a rough spec for the textual format but can't seem to find it right now to see whether binaryen or wabt is at fault or if this is just undefined behavior. I only see the super high level Text Format page.

Start with src/wasm/wasm-s-parser.cpp around line 1356 and reproduce the failure using wasm-opt with the textual module shown in the issue. Compare parsing when the table follows the function bodies versus when it precedes them, and check the WebAssembly text-format expectations. Done means valid input from wabt's wasm2wast is accepted without requiring the table to be moved.