Support for multiple modules

[abelstuker]

This PR fixes #27 by adding support for multiple modules, including shared memory, tables, globals and cross-module function calls.

Currently no official Wasm nor unofficial tests have been included in the Latch spectest suite. To test the multiple module functionality, see the test examples in /tutorials/wat/main/mtuliple_modules_mX.wast. These example tests include the demonstration of:

• inter-module function calls
  
• inter-module memory
• inter-module tables
• inter-module globals

You can provide multiple modules to the CLI by linking modules using the --link flag (e.g. ./wdcli mod1.wasm --link mod2.wasm mod3.wasm).

[abelstuker]

Should we include Latch spectests to cover this multi-module extension?
In that case, I presume Latch must be upgraded first for it to be capable of handling the compilation and linking of multiple modules?

[tolauwae]

I currently get this error when trying out the example:

➜ main (feat/multiple-modules) ✗ wdcli mod1.wasm --link mod2.wasm mod3.wasm
Assert Failed (WARDuino/src/WARDuino/WARDuino.cpp:603): Imported global mutability mismatch: imported=139, expected=1     
➜ main (feat/multiple-modules) ✗ echo $?
1

Also I used the TOPLLab fork of wat2wasm to get the binaries:

➜ main (feat/multiple-modules) ✗ wat2wasm --version
1.0.32 (git~1.0.27-176-g09d542f4)TOPLLab

Maybe I need to update this version?

[abelstuker]

@tolauwae
Mmmhh that's strange. I cannot reproduce this error (also using the TOPLLab wabt fork).
Are the wasm binaries formed as expected?

❯ wasm-objdump -x multiple_module_m1.wasm | grep global
 - global[0] i32 mutable=1 <- multiple_module_m3.counter

❯ wasm-objdump -x multiple_module_m3.wasm | grep global
 - global[0] i32 mutable=1 <counter> - init i32=100
 - global[0] -> "counter"

[tolauwae]

Yes I get the same output.

[abelstuker]

@tolauwae I see you compiled every multiple_module_mX.wast to modX.wasm. This, however, only works when you also update the import modules in those .wast files, as they expect the names of the (imported) modules to be in the multiple_module_mX format. Otherwise, they can't find the modules to import, resulting in this seemingly unrelated error.

[tolauwae]

I should have realised that 😅

[tolauwae]

Rebased. There were a lot of conflicts so I will run additional tests. But looks ready to merge.

[tolauwae]

Additional tests seem to find no more issues.

➜ main (feat/multiple-modules) ✗ wdcli multiple_module_m1.wasm --link multiple_module_m2.wasm multiple_module_m3.wasm 
=== Multi-module test ===
Cross-module call: 5 + 20 = 25
Table callback to table in M3 at index 0
M3: callback executed
Global counter: 100
Global counter +2: 102
Shared memory read: 8888