Fix Undefined Symbols while building llvm

[anutosh491]

Not sure why the upload to Quetz failed on all 3 previous updates on llvm

1. https://github.com/emscripten-forge/recipes/actions/runs/11376454739/job/31648960141
2. https://github.com/emscripten-forge/recipes/actions/runs/11209653508/job/31155192548
3. https://github.com/emscripten-forge/recipes/actions/runs/11052231541/job/30703847510

Need this for CppInterOp

[anutosh491]

Hmm, I thought the uploads failed but I see 19.1.2 here
https://beta.mamba.pm/channels/emscripten-forge/packages/llvm#info

Am I missing something ?

[DerThorsten]

@anutosh491 the upload only fails client sided, but not on the server side!
(ie the client believes there was a timeout...but usually stuff ends on the server)

[anutosh491]

Ahh cool. Needed llvm19 for CppInterOp which you already merged. Thanks for the clarification :)

[anutosh491]

Might just work out without the -sERROR_ON_UNDEFINED_SYMBOLS=0 flag too. Giving it an attempt !

[anutosh491]

I realized the way i was passing the flags was hampering the symbols. The minor change in the last commit fixes most of it. It's only this one symbol that is undefined

 │ │ wasm-ld: error: ../../../../lib/libclangInterpreter.a(Wasm.cpp.o): undefined symbol: lld::wasm::link(llvm::ArrayRef<char const*>, llvm::raw_ostream&, llvm:
 │ │ :raw_ostream&, bool, bool)

Need to figure out how to fix this. If anyone has ideas, they are welcome !

[anutosh491]

Hey @DerThorsten I see you had added this through ec21b92

recipes/recipes/recipes_emscripten/llvm/build.sh

Lines 7 to 8 in a4c4a03

	# clear LDFLAGS flags because they contain sWASM_BIGINT
	export LDFLAGS=""

Maybe we won't like to have WASM_BIGINT but don't we need any others maybe like this

-s NO_INVOKE_RUN -s EXIT_RUNTIME -s INITIAL_MEMORY=64MB -s ALLOW_MEMORY_GROWTH -s EXPORTED_RUNTIME_METHODS=FS,callMain -s MODULARIZE -s EXPORT_ES6

Just curious if we need to have no LDFLAGS :\ ?
Do you remember why you did this ?

[anutosh491]

This is now ready. The above link function symbol is available in lldWasm and once the latest Wasm.cpp file was introduced in 19.0 (llvm/llvm-project#86402) to help with running clang-repl and executing C++ code interactively in a wasm context ... we just need to link with lldWasm as the patch does.

[IsabelParedes]

🎉

[anutosh491]

thanks for the review :)