Emscripten: asm2wasm: Assertion `functionsMap.find(curr->name) == functionsMap.end()' failed

[malbarbo]

I got this assertion error trying to build libc-test (an rust crate).

The error can be reproduced running asm2wasm on this file.

[kripken]

Looks like that asm.js has a duplicate function,
function _memset($0,$1,$2) { function _memset(ptr, value, num) {
Do you have the bitcode that it was generated from? The bug is probably at the bitcode => asm.js level.

[malbarbo]

Here is it: libc_test-fe212f5bb0be8707.0.o.zip

I'm using rust 1.18, which uses llvm 4.0...

[malbarbo]

The same error happens with rust 1.17, which uses llvm 3.9.

[kripken]

I'm not able to test this on emscripten incoming (1.37.13), as I get
$ emcc libc_test-fe212f5bb0be8707.0.o llc: fastcomp/include/llvm/ADT/ilist_iterator.h:126: llvm::ilist_iterator<OptionsT, IsReverse, IsConst>::reference llvm::ilist_iterator<OptionsT, IsReverse, IsConst>::operator*() const [with OptionsT = llvm::ilist_detail::node_options<llvm::BasicBlock, true, false, void>; bool IsReverse = false; bool IsConst = false; llvm::ilist_iterator<OptionsT, IsReverse, IsConst>::reference = llvm::BasicBlock&]: Assertion `!NodePtr->isKnownSentinel()' failed.
Does that emcc command work for you? Or is there another way I should be reproducing the problem?

[malbarbo]

Thanks for investigate this.

I can execute emcc libc_test-fe212f5bb0be8707.0.o with sdk-1.37.13-64bit, but there is missing symbol errors.

I think that the best way is to execute the rust compiler... If you do not want to install the rust compiler in your system, you can run it inside a docker container (if you install rustup outside a container, you can uninstall it with the command rustup uninstall, which removes everything that was installed):

git clone https://github.com/malbarbo/libc --branch emscripten
docker run -it -v $(pwd)/libc:/libc ubuntu:16.04
apt-get update && apt-get install curl build-essential
curl https://sh.rustup.rs -sSf | sh # choose option 1
. ~/.profile # set PATH
rustup target add wasm32-unknown-emscripten
# install emscripten
cd /libc
RUSTFLAGS="-Z print-link-args" cargo run --target wasm32-unknown-emscripten -p libc-test

The artifacts are generate in target/wasm32-unknown-emscripten/debug/deps. Setting RUSTFLAGS will print the arguments used to call emcc.

[kripken]

If it doesn't crash for you with that version, then I suspect it's because the sdk build doesn't have assertions, while my local build does. I think we need to find out what's causing those asserts, as they could be the reason for the bug reported here (but it's also possible it's a red herring).

Perhaps is the bitcode old, or being linked with something old? A full rebuild from scratch of all bitcode files might help.

(I could try the rust compiler, but I don't know enough about it to easily debug into it. What I need here is just the emscripten commands it issues.)

[malbarbo]

Using emscripten incoming I got the same error as you.

I create a a zip file with all required obj files to generate an .js. The command emcc *.o *.rlib works fine, but the command emcc -s WASM=1 *.o *.rlib fail with the original assertion error.

[malbarbo]

To make it clear, using emcc libc_test-fe212f5bb0be8707.0.o gives the same assertion error you got, but given all object files as parameters works. Is this another issue?

[kripken]

Thanks, now I can see the problem directly. #5299 should fix it.

(I don't see those assertions again, btw - that might be an entirely separate issue. Very strange.)

[rfk]

FWIW I also hit this issue today in a different codebase, and can confirm that #5299 fixed it for me.

[kripken]

Thanks for confirming @rfk. Should be fixed now with that PR merged.

[malbarbo]

Thanks @kripken!

[lilianmoraru]

It would be nice to have this fix.
@kripken When do you think the next patch release might happen?

[kripken]

I tagged 1.37.14 now.

[lilianmoraru]

@kripken Thank you!!