Failed to build Stockfish.js with Emscripten

[laurent bernabe]

Hi,

I am aiming at building a custom version of StockfishJS in order to use it with React-Native.

I am using 

• Kubuntu 19.04 64 bits
• a recent version a Emscripten SDK (downloaded today) : not the incoming, but the standard version

So, I started to install emscripten sdk and try to build it in a standard way :

1. I went inside src subfolder of the repository sources
2. Launched the command 
   
   make build ARCH=wasm COMP=emscripten
   
   .
   

But it fails, the errors are joined in the output.txt.

The main error is 

shared:ERROR: '/home/laurent-bernabe/Programmes/emsdk/node/8.9.1_64bit/bin/node /home/laurent-bernabe/Programmes/emsdk/fastcomp/emscripten/src/compiler.js /tmp/tmpbZp3OW.txt /home/laurent-bernabe/Programmes/emsdk/fastcomp/ems
cripten/src/library_pthread_stub.js' failed (1)

Thanks in advance,

Regards

[laurent bernabe]

Here are the relevant scripts of Stockfish.js project, relating to emscripten building, joined with this message.

Thanks in advance, regards

[Mehdi Sabwat]

Hi,

Not sure what you mean by "standard version" for emsdk can I see the output of ./emsdk list?

Did you correctly set your env to point to the right sdk version?

I found this https://github.com/tdlib/td/issues/612, it seems it is the same issue.

It seems it is a work in progress, https://github.com/emscripten-core/emscripten/issues/8856, there is a workaround in the issue by adding this flag

 "-s EXPORTED_FUNCTIONS=['__cxa_begin_catch']"

to your compilation line.

I hope this helps,

Regards

[laurent bernabe]

Hi, thank you for your answer,

By standard version, I meant neither incoming nor lastest commit of emscripten

the result of

./emsdk list

is joint in the emsdk_config.txt file.

Also I'm having a look at the issue you pointed me to, and trying to solve it with either solution (addind flag -s EXPORTED_FUNCTIONS=['__cxa_begin_catch'], or testing the incoming commit  2aeae94

I'll also report the results of my tries here.

[laurent bernabe]

As for adding the flag

 "-s EXPORTED_FUNCTIONS=['__cxa_begin_catch']"

to the compilation command, it did not work either.

This how I processed to add this flag: editing the Makefile file (result joint in this message) in the emscripten section for wasm (lines 293 & 294)

And I've joint the result in this message, where you can see the added flag in several lines.

The error is given as 

shared:ERROR: undefined exported function: "__cxa_begin_catch"

So I still have to experiment the other option : I mean testing with the particular commit of the incoming branch.

[Floh]

This is the relevant error from the attached error log:

> error: undefined symbol: __cxa_uncaught_exception

...may be related to this ticket: https://github.com/emscripten-core/emscripten/issues/8856

Cheers,

-Floh.

[Mehdi Sabwat]

works with latest-upstream and removing fno-exceptions:

diff --git a/src/Makefile b/src/Makefile
index 7d4d3014..acbbd65e 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -177,7 +177,7 @@ ifeq ($(STATIC),1)
        CXXFLAGS += -static
 endif
 
-CXXFLAGS += -Wall -Wcast-qual -fno-exceptions -std=c++11 $(EXTRACXXFLAGS)
+CXXFLAGS += -Wall -Wcast-qual -std=c++11 $(EXTRACXXFLAGS)
 DEPENDFLAGS += -std=c++11
 LDFLAGS += $(EXTRALDFLAGS)
 

[laurent bernabe]

Yes thank you,

for that purpose, I am downloading and installing latest versions of clang-tool and sdk incoming.

It is taking long, so I'll post results of retrying whenever installations are done.

Regards

[laurent bernabe]

I don't understand, as emsdk does not seem to have any Makefile

[Mehdi Sabwat]

This is your Makefile we are talking about. The one located in stockfish.js src/

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[laurent bernabe]

Ok thanks,

will apply modifications and try build again

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[laurent bernabe]

Ok, I managed to build it.

In fact I missed to apply the patch of Mehdi Sabwat some posts above

Thank you all again for your helps.

Regards