Investigate and Decide on WebAssembly Backend Implementation Options for Theta

[alexdovzhanyn]

Investigate options for targeting WebAssembly as the language backend. Decide whether to use WebAssembly Text Format (WAT) or directly compile to WebAssembly binary (WASM). Additionally, explore the possibility of using LLVM as a target Intermediate Representation (IR) for compiling to WebAssembly.

Subtasks:

• [x] Research the pros and cons of using WebAssembly Text Format (WAT) versus directly compiling to WebAssembly binary (WASM).
• [x] Evaluate the feasibility of using LLVM as a target IR for the Theta language.
• [x] Determine the necessary steps to integrate LLVM with the Theta compiler for WebAssembly output.
• [x] Document the findings and make a recommendation on the best approach to implement WebAssembly support for Theta.

[alexdovzhanyn]

Research: LLVM vs. WASM

The Case for LLVM

Targeting LLVM as a backend would allow the language to produce native code for all major architectures. LLVM can also compile to WASM, supporting both native and WASM VM options. With built-in code optimization, LLVM makes it easier to generate efficient code.

The Case for WASM

Targeting WASM as the backend simplifies code generation. Since the language is educational, high performance isn't a priority. WASM's built-in garbage collection (GC) and support for control flow structures make it a better fit for a high-level language. Compiling directly to WASM is also faster than using LLVM.

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Pros and Cons

LLVM

• Pros:

  • Supports native execution on all architectures.
  • Can compile to WASM.
  • Built-in code optimization.
  • Fastest runtime.

• Cons:

  • More complex to implement.
  • Slower compilation.
  • No native control flow support.
  • No built-in GC.

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WASM

• Pros:

  • Easier to implement.
  • Built-in GC support.
  • Faster compilation.
  • Native control flow support.

• Cons:

  • Slower runtime (~10-15% slower than native).
  • Requires a VM to run (can be compiled to native using tools like Wasmer).

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Verdict

We will target WASM as the backend for the language. WASM allows the language to be more flexible and high-level, aligning with the project's goals. For native compilation, we can use tools like Wasmer to convert our WASM output to native code, maintaining flexibility and ease of implementation.