Final link step crashes on 1.38.30

[mdboom]

I recently upgraded the pyodide build from 1.38.22 to 1.38.30, and I'm getting the following during the final link step. Any ideas as to where to look?

em++ -s EXPORT_NAME="'pyodide'" -o build/pyodide.asm.html src/main.bc src/jsimport.bc src/jsproxy.bc src/js2python.bc src/pyimport.bc src/pyproxy.bc src/python2js.bc src/python2js_buffer.bc src/runpython.bc src/hiwire.bc \                               
  -O3 -s MODULARIZE=1 cpython/installs/python-3.7.0/lib/libpython3.7.a lz4/lz4-1.8.3/lib/liblz4.a -s "BINARYEN_METHOD='native-wasm'" -s TOTAL_MEMORY=1073741824 -s ALLOW_MEMORY_GROWTH=1 -s MAIN_MODULE=1 -s EMULATED_FUNCTION_POINTERS=1 -s EMULATE_FUNCTION_POINTER_CASTS=1 -s LINKABLE=1 -s EXPORT_ALL=1 -s EXPORTED_FUNCTIONS='["___cxa_guard_acquire", "__ZNSt3__28ios_base4ini
tEPv"]' -s WASM=1 -s SWAPPABLE_ASM_MODULE=1 -s USE_FREETYPE=1 -s USE_LIBPNG=1 -std=c++14 -Lcpython/build/sqlite-autoconf-3270200/.libs -lsqlite3 -lstdc++ --memory-init-file 0 -s "BINARYEN_TRAP_MODE='clamp'" -s TEXTDECODER=0 -s LZ4=1 -s FORCE_FILESYSTEM=1                                                                                                                      cache:INFO: generating port: libz.a... (this will be cached in "/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/.emscripten_cache/asmjs/libz.a" for subsequent builds)        
cache:INFO:  - ok                                                                                                                                                                        
cache:INFO: generating port: libpng.bc... (this will be cached in "/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/.emscripten_cache/asmjs/libpng.bc" for subsequent builds)   root:INFO: building port: libpng                                                                                                                                                          create_lib /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/.emscripten_cache/asmjs/ports-builds/libpng/libpng.bc                                                              
cache:INFO:  - ok                                    
cache:INFO: generating port: libfreetype.a... (this will be cached in "/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/.emscripten_cache/asmjs/libfreetype.a" for subsequent bu
ilds)
cache:INFO:  - ok
cache:INFO: generating system library: libc++_noexcept.a... (this will be cached in "/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/.emscripten_cache/asmjs/libc++_noexcept.a"
 for subsequent builds)
cache:INFO:  - ok
cache:INFO: generating system library: libc++abi.bc... (this will be cached in "/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/.emscripten_cache/asmjs/libc++abi.bc" for subse
quent builds)
cache:INFO:  - ok
cache:INFO: generating system library: libc-wasm.bc... (this will be cached in "/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/.emscripten_cache/asmjs/libc-wasm.bc" for subse
quent builds)
cache:INFO:  - ok
emcc: warning: cannot represent a NaN literal '0x7cd89e0' with custom bit pattern in NaN-canonicalizing JS engines (e.g. Firefox and Safari) without erasing bits!
  in   %spec.select = select i1 %2, double 0x7FF8000000000000, double 0xFFF8000000000000 in _Py_dg_stdnan()
#0 0x00000000012930da llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc+0x12930d
a)
#1 0x00000000012911be llvm::sys::RunSignalHandlers() (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc+0x12911be)
#2 0x000000000129134d SignalHandler(int) (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc+0x129134d)
#3 0x00007fcbc3b69030 __restore_rt (/lib64/libpthread.so.0+0x13030)
#4 0x000000000081a691 (anonymous namespace)::JSWriter::CH_emscripten_atomic_exchange_u8(llvm::Instruction const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<
char> >, int) (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc+0x81a691)
#5 0x00000000007f581f (anonymous namespace)::JSWriter::getFunctionIndex(llvm::Function const*) (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1
.38.30_64/bin/llc+0x7f581f)
#6 0x000000000083b652 (anonymous namespace)::JSWriter::printFunctionBody(llvm::Function const*) (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e
1.38.30_64/bin/llc+0x83b652)
#7 0x000000000083cc80 (anonymous namespace)::JSWriter::printModuleBody() (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc+0x83
cc80)
#8 0x000000000084054b (anonymous namespace)::JSWriter::runOnModule(llvm::Module&) (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin
/llc+0x84054b)
#9 0x0000000000d82fe6 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc+0xd82
fe6)
#10 0x00000000005e6097 compileModule(char**, llvm::LLVMContext&) (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc+0x5e6097)
#11 0x00000000005a5724 main (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc+0x5a5724)
#12 0x00007fcbc3622413 __libc_start_main (/lib64/libc.so.6+0x24413)
#13 0x00000000005dbcae _start (/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc+0x5dbcae)
Stack dump:
0.      Program arguments: /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc /tmp/emscripten_temp_gv8782dx/pyodide.asm.bc -march
=js -filetype=asm -o /tmp/tmpkye2el_3.4.js -emscripten-stack-size=5242880 -O3 -emscripten-precise-f32 -emscripten-no-aliasing-function-pointers -emscripten-emulated-function-pointers -em
scripten-emulate-function-pointer-casts -emscripten-relocatable -emscripten-global-base=0 -emscripten-no-exit-runtime -emscripten-wasm
1.      Running pass 'JavaScript backend' on module '/tmp/emscripten_temp_gv8782dx/pyodide.asm.bc'.
shared:ERROR: '/home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc /tmp/emscripten_temp_gv8782dx/pyodide.asm.bc -march=js -filetype=asm -o /tmp/tmpkye2el_3.4.js -emscripten-stack-size=5242880 -O3 -emscripten-precise-f32 -emscripten-no-aliasing-function-pointers -emscripten-emulated-function-pointers -emscripten-emulate-function-pointer-casts -emscripten-relocatable -emscripten-global-base=0 -emscripten-no-exit-runtime -emscripten-wasm' failed (-11)
make: *** [Makefile:67: build/pyodide.asm.js] Error 1

[kripken]

Is it hitting an assertion there? or a segfault? I feel like usually the full error message makes that clear but I don't see enough to tell.

May be worth trying this in a debug build with assertions, and/or in valgrind.

This doesn't sound like a familiar issue, though. Perhaps something isn't set up right, like fastcomp wasnt rebuilt or using an old version by mistake? Perhaps a reinstall would help.

[mdboom]

Thanks. This was from a completely fresh build, fwiw. I'll try a debug build.

[mdboom]

Here's the output from Valgrind, in case this provides clues:

==18847== Invalid read of size 1
==18847==    at 0x81A691: (anonymous namespace)::JSWriter::CH_emscripten_atomic_exchange_u8(llvm::Instruction const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, int) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x7F581E: (anonymous namespace)::JSWriter::getFunctionIndex(llvm::Function const*) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x83B651: (anonymous namespace)::JSWriter::printFunctionBody(llvm::Function const*) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x83CC7F: (anonymous namespace)::JSWriter::printModuleBody() (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x84054A: (anonymous namespace)::JSWriter::runOnModule(llvm::Module&) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0xD82FE5: llvm::legacy::PassManagerImpl::run(llvm::Module&) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x5E6096: compileModule(char**, llvm::LLVMContext&) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x5A5723: main (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==  Address 0x17 is not stack'd, malloc'd or (recently) free'd
==18847== 
==18847== 
==18847== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==18847==  Access not within mapped region at address 0x17
==18847==    at 0x81A691: (anonymous namespace)::JSWriter::CH_emscripten_atomic_exchange_u8(llvm::Instruction const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, int) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x7F581E: (anonymous namespace)::JSWriter::getFunctionIndex(llvm::Function const*) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x83B651: (anonymous namespace)::JSWriter::printFunctionBody(llvm::Function const*) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x83CC7F: (anonymous namespace)::JSWriter::printModuleBody() (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x84054A: (anonymous namespace)::JSWriter::runOnModule(llvm::Module&) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0xD82FE5: llvm::legacy::PassManagerImpl::run(llvm::Module&) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x5E6096: compileModule(char**, llvm::LLVMContext&) (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)
==18847==    by 0x5A5723: main (in /home/mdboom/Work/builds/compiling/pyodide.tmp/emsdk/emsdk/clang/tag-e1.38.30/build_tag-e1.38.30_64/bin/llc)

[kripken]

Hmm, that function assumes the input function has 2 operands - maybe that's the problem? Hard to see how that could fail though. Adding errs() << *CI << '\n' may help understand things. I can try that if you send me the bitcode.

[mdboom]

I added that line and recompiled, but it doesn't seem to be producing additional output.

I've also sent you a copy of the bytecode via e-mail.

[mdboom]

It looks like CI is a NULL pointer (which is why I wasn't seeing any output from that before).

[kripken]

Thanks, this should fix it, please confirm emscripten-core/emscripten-fastcomp#256

[mdboom]

Yep, the linked PR works for me!