I think the reason that both types of binaries (those built with gcc4 and gcc5) work with the newer libstdc++ is that it has both older and newer versions of the relevant symbols. For example:
$ readelf -s ~/Downloads/libstdc++.so.6.0.21 ... <symbol dump> 84: 00000000000c6ee0 50 FUNC WEAK DEFAULT 12 _ZNSt15basic_stringbufIwS@@GLIBCXX_3.4 ... 265: 00000000000c6c20 380 FUNC WEAK DEFAULT 12 _ZNSt15basic_stringbufIwS@@GLIBCXX_3.4.21 This is done exactly so that software complied against older libstdc++ will still work. So newer libstdc++ should work for you. However if you build things on a newer system and try to run them on an older system, you'll need to also watch out for possible similar versioning issues from any other shared libs that the binaries depend on; most notably libc. One possible way to work around this for libstdc++ is that gcc has a flag -static-libstdc++ that causes libstdc++ to be linked statically rather than dynamically, so there will be no runtime dependence on libstdc++ in the resulting binary. So for the SDK prebuilts we could build our tools with that flag to hopefully avoid this problem. In the PNaCl toolchain we build the toolchain on a quite-old version of Ubuntu (this avoids libc and other issues) but this means that we have to build and bundle our own copy of libc++ because the version of libstdc++ on that system isn't new enough to build LLVM. On Fri, Dec 9, 2016 at 12:48 PM <[email protected]> wrote: > Hi, > > I've now done a fresh checkout of emsdk and followed the instructions you > posted in > https://github.com/kripken/emscripten/issues/4682#issuecomment-260159020 > . Unfortunately I still experienced some issues with the prebuilt Clang > and Emscripten distributions. This was on a 64bit Ubuntu 14.04 box. > Fortunately I did manage to work around these issue. Details below: > > The binary toolchain downloaded fine, and the SDK activated fine. > Unfortunately emcc would not run: > > ljw@ljw-desktop:~/src/emsdk$ ./emsdk activate --embedded > sdk-nightly-latest-64bit > Writing .emscripten configuration file to Emscripten SDK directory > /home/ljw/src/emsdk > The Emscripten configuration file /home/ljw/src/emsdk/.emscripten has been > rewritten with the following contents: > > import os > emsdk_path=os.path.dirname(os.environ.get('EM_CONFIG')).replace('\\', '/') > LLVM_ROOT='' + emsdk_path + '/clang/nightly-e1.36.14-2016_12_08_07_01' > NODE_JS='' + emsdk_path + '/node/4.1.1_64bit/bin/node' > EMSCRIPTEN_ROOT='' + emsdk_path + > '/emscripten/nightly-1.36.14-2016_12_08_07_01' > SPIDERMONKEY_ENGINE = '' > V8_ENGINE = '' > TEMP_DIR = '' + emsdk_path + '/tmp' > COMPILER_ENGINE = NODE_JS > JS_ENGINES = [NODE_JS] > > To conveniently access the selected set of tools from the command line, > consider adding the following directories to PATH, or call 'source > ./emsdk_env.sh' to do this for you. > > > > /home/ljw/src/emsdk:/home/ljw/src/emsdk/clang/nightly-e1.36.14-2016_12_08_07_01:/home/ljw/src/emsdk/node/4.1.1_64bit/bin:/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01 > ljw@ljw-desktop:~/src/emsdk$ source ./emsdk_env.sh > Adding directories to PATH: > PATH += /home/ljw/src/emsdk > PATH += /home/ljw/src/emsdk/clang/nightly-e1.36.14-2016_12_08_07_01 > PATH += /home/ljw/src/emsdk/node/4.1.1_64bit/bin > PATH += /home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01 > > Setting environment variables: > EMSDK = /home/ljw/src/emsdk > EM_CONFIG = /home/ljw/src/emsdk/.emscripten > EM_CACHE = /home/ljw/src/emsdk/.emscripten_cache > EMSCRIPTEN = > /home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01 > > I then ran emcc and got the following error: > > ljw@ljw-desktop:~/src/emsdk$ emcc > CRITICAL:root:Could not verify LLVM version: argument of type 'NoneType' > is not iterable > /home/ljw/src/emsdk/clang/nightly-e1.36.14-2016_12_08_07_01/llc: > /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.20' not > found (required by > /home/ljw/src/emsdk/clang/nightly-e1.36.14-2016_12_08_07_01/llc) > /home/ljw/src/emsdk/clang/nightly-e1.36.14-2016_12_08_07_01/llc: > /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.21' not > found (required by > /home/ljw/src/emsdk/clang/nightly-e1.36.14-2016_12_08_07_01/llc) > CRITICAL:root:fastcomp in use, but LLVM has not been built with the > JavaScript backend as a target, llc reports: > =========================================================================== > (no targets could be identified: need more than 1 value to unpack) > =========================================================================== > CRITICAL:root:you can fall back to the older (pre-fastcomp) compiler core, > although that is not recommended, see > http://kripken.github.io/emscripten-site/docs/building_from_source/LLVM-Backend.html > INFO:root:(Emscripten: Running sanity checks) > CRITICAL:root:failing sanity checks due to previous fastcomp failure > > As I mentioned in my previous message, the "'GLIBCXX_*' not found" errors > above are due to emscripten-fastcomp being built with GCC 5.X. In order to > run these programs I needed a copy of libstdc++.so from GCC5. Building GCC5 > would be time consuming, so I instead obtained an appropriate libstdc++.so > binary from the ubuntu-toolchain-r PPA. I didn't want to modify my host > system so I downloaded the deb, verified and extracted it, and then put the > libstdc++.so in my path: > > wget > http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu/pool/main/g/gcc-5/libstdc++6_5.1.0-0ubuntu11~10.04.2_amd64.deb > wget > http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu/dists/lucid/Release > wget > http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu/dists/lucid/Release.gpg > wget > http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu/dists/lucid/main/binary-amd64/Packages > > Note that I've downloaded the Lucid version (Ubuntu 10.04). I just did > this so I could use the same binary on both Ubuntu 12.04 and 14.04 (though > I've not tested 12.04 yet). > > mv Release.gpg Release.asc > > Then verified: > > ljw@ljw-desktop:~/src/emsdk/my_deb$ gpg --verify Release.asc > gpg: Signature made Sun 26 Apr 2015 05:11:17 BST using RSA key ID BA9EF27F > gpg: Good signature from "Launchpad Toolchain builds" > gpg: WARNING: This key is not certified with a trusted signature! > gpg: There is no indication that the signature belongs to the > owner. > Primary key fingerprint: 60C3 1780 3A41 BA51 845E 371A 1E93 77A2 BA9E F27F > > ljw@ljw-desktop:~/src/emsdk/my_deb$ sha256sum Packages > fed61ce85f21b5a5e9c5d9e6c76ad3f5b24a775750fff61c5b224e2c8357f606 Packages > ljw@ljw-desktop:~/src/emsdk/my_deb$ grep > fed61ce85f21b5a5e9c5d9e6c76ad3f5b24a775750fff61c5b224e2c8357f606 Release > fed61ce85f21b5a5e9c5d9e6c76ad3f5b24a775750fff61c5b224e2c8357f606 > 328682 main/binary-amd64/Packages > ljw@ljw-desktop:~/src/emsdk/my_deb$ sha256sum > libstdc++6_5.1.0-0ubuntu11~10.04.2_amd64.deb > 3742f82b49b214f03c3531dd63be860ee63409788497f1b368cd465cabb5ec1c > libstdc++6_5.1.0-0ubuntu11~10.04.2_amd64.deb > ljw@ljw-desktop:~/src/emsdk/my_deb$ grep > 3742f82b49b214f03c3531dd63be860ee63409788497f1b368cd465cabb5ec1c -A 9 -B 15 > Packages > Package: libstdc++6 > Source: gcc-5 > Priority: important > Section: libs > Installed-Size: 2040 > Maintainer: Ubuntu Core developers <[email protected]> > Architecture: amd64 > Version: 5.1.0-0ubuntu11~10.04.2 > Replaces: libstdc++6-5-dbg (<< 4.9.0-3) > Depends: gcc-5-base (= 5.1.0-0ubuntu11~10.04.2), libc6 (>= 2.11), libgcc1 > (>= 1:4.1.1) > Conflicts: scim (<< 1.4.2-1) > Filename: pool/main/g/gcc-5/libstdc++6_5.1.0-0ubuntu11~10.04.2_amd64.deb > Size: 525688 > MD5sum: 91e20fab6550dbe12ba4287a2cabc737 > SHA1: 4f79929ae9f17ab7ca95fbd9b9629c1ec8c66421 > SHA256: 3742f82b49b214f03c3531dd63be860ee63409788497f1b368cd465cabb5ec1c > Description: GNU Standard C++ Library v3 > This package contains an additional runtime library for C++ programs > built with the GNU compiler. > . > libstdc++-v3 is a complete rewrite from the previous libstdc++-v2, which > was included up to g++-2.95. The first version of libstdc++-v3 appeared > in g++-3.0. > Original-Maintainer: Debian GCC Maintainers <[email protected]> > > I then extracted the deb and put the libstdc++.so in my LD_LIBRARY_PATH: > > ljw@ljw-desktop:~/src/emsdk/my_deb$ ar xv > libstdc++6_5.1.0-0ubuntu11~10.04.2_amd64.deb > x - debian-binary > x - control.tar.gz > x - data.tar.gz > ljw@ljw-desktop:~/src/emsdk/my_deb$ tar xvf data.tar.gz > ./ > ./usr/ > ./usr/lib/ > ./usr/lib/libstdc++.so.6.0.21 > ... > ./usr/lib/libstdc++.so.6 > ./usr/share/doc/libstdc++6 > ljw@ljw-desktop:~/src/emsdk/my_deb$ cd usr/lib/ > ljw@ljw-desktop:~/src/emsdk/my_deb/usr/lib$ ls > libstdc++.so.6 libstdc++.so.6.0.21 > ljw@ljw-desktop:~/src/emsdk/my_deb/usr/lib$ export > LD_LIBRARY_PATH=${PWD}:$LD_LIBRARY_PATH > > I was then able to run emcc: > > ljw@ljw-desktop:~$ emcc > INFO:root:(Emscripten: Running sanity checks) > WARNING:root:no input files > > I then attempted to run: > > python $EMSCRIPTEN/embuilder.py build ALL > > This was mostly successful, but it errored out building the > native_optimizer: > > INFO:root:building and verifying native_optimizer > module.js:338 > throw err; > ^ > > Error: Cannot find module '../tools/eliminator/node_modules/uglify-js' > at Function.Module._resolveFilename (module.js:336:15) > at Function.Module._load (module.js:286:25) > at Module.require (module.js:365:17) > at require (module.js:384:17) > at Object.<anonymous> > (/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/tools/js-optimizer.js:132:14) > at Module._compile (module.js:434:26) > at Object.Module._extensions..js (module.js:452:10) > at Module.load (module.js:355:32) > at Function.Module._load (module.js:310:12) > at Function.Module.runMain (module.js:475:10) > Traceback (most recent call last): > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/emcc", > line 13, in <module> > emcc.run() > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/emcc.py", > line 1877, in run > JSOptimizer.flush() > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/emcc.py", > line 1773, in flush > run_passes(chunks[0], title, just_split=False, just_concat=False) > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/emcc.py", > line 1746, in run_passes > final = shared.Building.js_optimizer(final, passes, debug_level >= 4, > JSOptimizer.extra_info, just_split=just_split, just_concat=just_concat) > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/tools/shared.py", > line 1829, in js_optimizer > ret = js_optimizer.run(filename, passes, NODE_JS, debug, extra_info, > just_split, just_concat) > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/tools/js_optimizer.py", > line 559, in run > return temp_files.run_and_clean(lambda: run_on_js(filename, passes, > js_engine, source_map, extra_info, just_split, just_concat)) > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/tools/tempfiles.py", > line 78, in run_and_clean > return func() > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/tools/js_optimizer.py", > line 559, in <lambda> > return temp_files.run_and_clean(lambda: run_on_js(filename, passes, > js_engine, source_map, extra_info, just_split, just_concat)) > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/tools/js_optimizer.py", > line 378, in run_on_js > asm_shell_pre, asm_shell_post = minifier.minify_shell(asm_shell, > 'minifyWhitespace' in passes, source_map).split('EMSCRIPTEN_FUNCS();'); > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/tools/js_optimizer.py", > line 247, in minify_shell > assert len(output) > 0 and not output.startswith('Assertion failed'), > 'Error in js optimizer: ' + output > AssertionError: Error in js optimizer: > Traceback (most recent call last): > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/embuilder.py", > line 147, in <module> > ''', ['optimizer.2.exe'], ['-O2']) > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/embuilder.py", > line 69, in build > shared.Building.emcc(temp, args, output_filename=temp_js) > File > "/home/ljw/src/emsdk/emscripten/nightly-1.36.14-2016_12_08_07_01/tools/shared.py", > line 1722, in emcc > assert os.path.exists(output_filename), 'emcc could not create output > file: ' + output_filename > AssertionError: emcc could not create output file: > /home/ljw/src/emsdk/tmp/tmpMioyG3.js > > For some reason uglify-js does not seem to be distributed with the > Emscripten tarball downloaded by emsdk. Is this intended? I was able to > resolve this issue by copying across tools/eliminator/node_modules from a > git checkout of Emscripten. > > I'm also slightly dubious about my approach of using libstdc++.so from > GCC5. This makes emscripten-fastcomp binaries work, but I expected it to > fail when I attempted to run the native optimizer. The native optimizer > will be built using the system copy of GCC 4.8. This will link against > libstdc++ from GCC 4.8, but at runtime (due to the LD_LIBRARY_PATH) it will > run against the libstdc++ from GCC5. In theory these two versions of > libstdc++ are ABI incompatible for C++11 code. I ran python tests/runner.py > random100 and got no unexpected failures (other than SIMD/pthread stuff). > Maybe we got lucky and the native optimizer just doesn't happen to hit any > of the incompatible ABI paths. I suppose that if it did become a problem I > could just reset the LD_LIBRARY_PATH whenever executing the native > optimizer. > > Thanks > Liam Wilson > > > On Thursday, 8 December 2016 08:19:14 UTC, jj wrote: > > Oh, the command is actually "emsdk update-tags" and not "emsdk update > -tags". > > When you are using emsdk via git, "emsdk update" should not be used. > (marked down a note to improve emsdk to detect when it's being used via git > to make this obvious) > > The "emsdk update-tags" feature is a new one, which is not yet present in > the latest bundled version, which is why it got confused here. > > Try following the command line presented at > https://github.com/kripken/emscripten/issues/4682#issuecomment-260159020 > to the letter. Verified this to work locally, the run should look like this: > > C:\code\emsdk>emsdk update-tags > Fetching all tags from Emscripten Github repository... > Done. 86 tagged releases available, latest is 1.36.14. > Fetching all precompiled Nightly versions.. > Downloading: C:/code/emsdk/llvm-nightlies-32bit.txt from > https://s3.amazonaws.com/mozilla-games/emscripten/packages/llvm/nightly/win_32bit/index.txt > Downloading: C:/code/emsdk/llvm-nightlies-64bit.txt from > https://s3.amazonaws.com/mozilla-games/emscripten/packages/llvm/nightly/win_64bit/index.txt > Downloading: C:/code/emsdk/emscripten-nightlies.txt from > https://s3.amazonaws.com/mozilla-games/emscripten/packages/emscripten/nightly/win/index.txt > > C:\code\emsdk>emsdk install sdk-nightly-latest-64bit > Installing SDK 'sdk-nightly-1.36.14-2016_11_11_00_55-64bit'.. > Installing tool 'clang-nightly-e1.36.14-2016_11_11_00_55-64bit'.. > Downloading: > C:/code/emsdk/zips/emscripten-llvm-e1.36.14-2016_11_11_00_55.zip from > https://s3.amazonaws.com/mozilla-games/emscripten/packages/llvm/nightly/win_64bit/emscripten-llvm-e1.36.14-2016_11_11_00_55.zip > ... > > Try doing a fresh git clone to undo the changes that "emsdk update" did on > the git repository. > > > 2016-12-06 2:32 GMT+02:00 <[email protected]>: > > I'm having a bit of trouble downloading the precompiled binaries using the > instructions from > https://github.com/kripken/emscripten/issues/4682#issuecomment-260159020 > > (precise)ljw@localhost:~/src/emsdk$ ./emsdk update -tags > Downloading: /home/ljw/src/emsdk/zips/emsdk_unix_update.tar.gz from > https://s3.amazonaws.com/mozilla-games/emscripten/packages/emsdk_unix_update.tar.gz > Unpacking '/home/ljw/src/emsdk/zips/emsdk_unix_update.tar.gz' to > '/home/ljw/src/emsdk' > emsdk_portable/emscripten-tags.txt > emsdk_portable/emsdk > emsdk_portable/emsdk_env.sh > emsdk_portable/emsdk_manifest.json > emsdk_portable/README.md > Fetching all tags from Emscripten Github repository... > Done. 86 tagged releases available, latest is 1.36.14. > Fetching all precompiled Nightly versions.. > Downloading: /home/ljw/src/emsdk/llvm-nightlies-32bit.txt from > https://s3.amazonaws.com/mozilla-games/emscripten/packages/llvm/nightly/linux_32bit/index.txt > Downloading: /home/ljw/src/emsdk/llvm-nightlies-64bit.txt from > https://s3.amazonaws.com/mozilla-games/emscripten/packages/llvm/nightly/linux_64bit/index.txt > Downloading: /home/ljw/src/emsdk/emscripten-nightlies.txt from > https://s3.amazonaws.com/mozilla-games/emscripten/packages/emscripten/nightly/linux/index.txt > (precise)ljw@localhost:~/src/emsdk$ ./emsdk install > sdk-nightly-latest-64bit > Error: No tool or SDK found by name 'sdk-nightly-latest-64bit'. > > I did manage to download a fastcomp binary directly from > https://s3.amazonaws.com/mozilla-games/emscripten/packages/llvm/nightly/linux_64bit/emscripten-llvm-latest.tar.gz > . Unfortunately the downloaded binary will not run on Ubuntu 12.04 or > 14.04. I see the following error: > > (precise)ljw@localhost:~/Downloads/fastcomp/emscripten-llvm-e1.36.14-2016_12_04_02_39$ > ./clang > ./clang: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version > `GLIBCXX_3.4.18' not found (required by ./clang) > ./clang: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version > `GLIBCXX_3.4.20' not found (required by ./clang) > ./clang: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version > `GLIBCXX_3.4.21' not found (required by ./clang) > > This suggests clang was built with some GCC 5.X (based on the symbol > versioning doc: https://gcc.gnu.org/onlinedocs/libstdc++/manual/abi.html > "GCC 5.1.0: GLIBCXX_3.4.21, CXXABI_1.3.9"). I assume it was built with GCC > 5.3 on Ubuntu 16.04? > > I came up with the following solution. I built emscripten-fastcomp under > Centos 6. This involved building GCC 4.8.5 and Cmake 3.5.2 under Centos 6. > I then used my freshly built GCC and CMake to build emscripten-fastcomp. > This gave me a fastcomp binary that only depends on glibc 2.12 and the > version of libstdc++ that ships with GCC 4.8.5. I also set up Emscripten > under Centos 6 and ran a chunk of the test suite. This involves building > Python 2.7 from source and installing prebuilt binaries of node.js, > Spidermonkey, and the JRE. With a bit of fiddling around I was able to put > together a Emscripten 1.36.14 binary distribution that worked on Centos 6, > Ubuntu 12.04 and Ubuntu 14.04 (and in theory a wide range of other 64bit > Linux distribution). > > Very rough instructions to this approach here: > https://gist.github.com/cosinusoidally/16ad712d2659dbf4f65a1d823ae35fbd > > Thanks > Liam Wilson > > > On Sunday, 4 December 2016 01:40:20 UTC, jj wrote: > > The Emscripten build bots do precompiled Nightly builds and upload them to > S3. > https://github.com/kripken/emscripten/issues/4682#issuecomment-260159020 > has the command line steps to bootstrap to the latest Nightlies. > > 2016-11-27 16:18 GMT+02:00 Juha Järvi <[email protected]>: > > To get Emscripten working quickly with Travis tests > <https://github.com/charto/nbind/blob/master/bin/ci-trigger> in nbind > <https://github.com/charto/nbind#readme> I copied the strategy used in > Urho3D <https://urho3d.github.io/> (see the html5 build) and removed the > Ruby dependency. Basically I set up a new nearly empty Github repo > <https://github.com/charto/nbind-ci-emscripten>, wrote the script in the > first link in this post and forked Urho3D's precompiled Emscripten repo > <https://github.com/urho3d/emscripten-sdk>. It doesn't get updated all > the time, but often enough for me. > > > tiistai 8. marraskuuta 2016 19.06.14 UTC+2 Shlomi Fish kirjoitti: > > Hi all! > > I'm using Emscripten to convert Freecell Solver's source code > ( http://fc-solve.shlomifish.org/ ) for use in the online site. I'd like > to add > the site's build+tests process to fc-solve's Travis-CI continuous > integration > process and Emscripten is part of its "make stage". Travis-CI gives me an > Ubuntu LTS x86-64 VM and allows setting up PPAs or fetching binaries, but > building Emscripten completely from source will be too time consuming and > prohibitive. > > Can anyone refer me to a PPA or precompiled binaries suitable for > installing and running on Ubuntu x86-64 for Emscripten? I'll be grateful > for > any insights. > > Regards, > > Shlomi Fish > > -- > ----------------------------------------------------------------- > Shlomi Fish http://www.shlomifish.org/ > https://youtu.be/GoEn1YfYTBM - Tiffany Alvord - “Fall Together” > > It does not mean what I think it means, but it means what *you* think it > means. > > Please reply to list if it's a mailing list post - http://shlom.in/reply > . > > -- > You received this message because you are subscribed to the Google Groups > "emscripten-discuss" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > > > -- > You received this message because you are subscribed to the Google Groups > "emscripten-discuss" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > > > -- > You received this message because you are subscribed to the Google Groups > "emscripten-discuss" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "emscripten-discuss" group. 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