JS: Missing missing HEAP8 in EMCC EXPORTED_RUNTIME_METHODS #2427
Description
GHC issue: https://gitlab.haskell.org/ghc/ghc/-/issues/26290
Summary
Cannot run any resulting JS code on GHC-9.12.2 and emscripten-4.0.8 built via haskell.nix.
Steps to reproduce
main :: IO ()
main = putStrLn "Hello world!"
running it results in:
Aborted('HEAP8' was not exported. add it to EXPORTED_RUNTIME_METHODS (see the Emscripten FAQ))
/nix/store/hwd9jkdfr19bazq3j7mc05crg2kxl4am-hello-world-exe-hello-world-0.1.0.0/bin/hello-world:52245
var e = new WebAssembly.RuntimeError(what);
Expected behavior
Hello world!
Environment
- GHC version used: 9.12.2
Optional:
- Operating System: NixOS
- System Architecture: x86_64
- Haskell.nix version (or commit) used: e567ebc (tag: 2025.08.03)
Fix
-----------------------
modified: rts/js/mem.js
-----------------------
@@ -1,5 +1,5 @@
//#OPTIONS:CPP
-//#OPTIONS:EMCC:EXPORTED_RUNTIME_METHODS=addFunction,removeFunction,getEmptyTableSlot
+//#OPTIONS:EMCC:EXPORTED_RUNTIME_METHODS=addFunction,removeFunction,getEmptyTableSlot,HEAP8