Attempting to compile with 3.0.1-git and -fwasm-exceptions fails with clang error

[yowl]

Using this command line (i've added the new lines)

E:\GitHub\emsdk\upstream\emscripten\emcc.bat "E:\GitHub\runtimelab\artifacts\tests\coreclr\Browser.wasm.Debug\nativeaot\SmokeTests\Exceptions\Exceptions\native\Exceptions.bc" \
-c -o "E:\GitHub\runtimelab\artifacts\tests\coreclr\Browser.wasm.Debug\nativeaot\SmokeTests\Exceptions\Exceptions\native\Exceptions.o" \
-s ERROR_ON_UNDEFINED_SYMBOLS=0 -g -fwasm-exceptions

Produces the error

shared:INFO: (Emscripten: Running sanity checks)
emcc: warning: linker setting ignored during compilation: 'ERROR_ON_UNDEFINED_SYMBOLS' [-Wunused-command-line-argument]
fatal error: error in backend: -wasm-enable-eh only allowed with -exception-model=wasm
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: E:/GitHub/emsdk/upstream/bin\\clang++.exe -target wasm32-unknown-emscripten -DEMSCRIPTEN -fvisibility=default -mllvm -combiner-global-alias-analysis=false -mllvm -enable-emscripten-sjlj -mllvm -disable-lsr -D__EMSCRIPTEN_major__=3 -D__EMSCRIPTEN_minor__=0 -D__EMSCRIPTEN_tiny__=1 -D_LIBCPP_ABI_VERSION=2 -Werror=implicit-function-declaration -Xclang -iwithsysroot/include/SDL --sysroot=E:\\GitHub\\emsdk\\upstream\\emscripten\\cache\\sysroot -Xclang -iwithsysroot/include\\compat -c -g -fwasm-exceptions E:\\GitHub\\runtimelab\\artifacts\\tests\\coreclr\\Browser.wasm.Debug\\nativeaot\\SmokeTests\\Exceptions\\Exceptions\\native\\Exceptions.bc -o E:\\GitHub\\runtimelab\\artifacts\\tests\\coreclr\\Browser.wasm.Debug\\nativeaot\\SmokeTests\\Exceptions\\Exceptions\\native\\Exceptions.o
 #0 0x00007ffd9d504f69 (C:\WINDOWS\System32\KERNELBASE.dll+0x34f69)
 #1 0x00007ff75f380d4a (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x610d4a)
#2 0x00007ff75f3b7d09 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x647d09)
 #3 0x00007ff75ed78191 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x8191)
 #4 0x00007ff75f381f3d (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x611f3d)
 #5 0x00007ff75f381e05 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x611e05)
 #6 0x00007ff75edd0c8d (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x60c8d)
 #7 0x00007ff75f6bbb9b (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x94bb9b)
 #8 0x00007ff75f69317d (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x92317d)
 #9 0x00007ff75ff5d942 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x11ed942)
#10 0x00007ff75ff571be (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x11e71be)
#11 0x00007ff76032df14 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x15bdf14)
#12 0x00007ff76029d534 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x152d534)
#13 0x00007ff75f506a93 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x796a93)
#14 0x00007ff75f595ceb (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x825ceb)
#15 0x00007ff75ed77ec3 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x7ec3)
#16 0x00007ff75ed74cf4 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x4cf4)
#17 0x00007ff7600619a6 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x12f19a6)
#18 0x00007ff75f380b92 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x610b92)
#19 0x00007ff760061631 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x12f1631)
#20 0x00007ff75f4cc1e5 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x75c1e5)
#21 0x00007ff75f4cc6cb (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x75c6cb)
#22 0x00007ff75f4e1a57 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x771a57)
#23 0x00007ff75ed74505 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x4505)
#24 0x00007ff76243cd54 (E:\GitHub\emsdk\upstream\bin\clang++.exe+0x36ccd54)
#25 0x00007ffd9f5a7034 (C:\WINDOWS\System32\KERNEL32.DLL+0x17034)
#26 0x00007ffd9fbc2651 (C:\WINDOWS\SYSTEM32\ntdll.dll+0x52651)
clang++: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 14.0.0 (https://github.com/llvm/llvm-project 5d49511b3058cac17eb80d243d3e2ad5cb0cddb9)
Target: wasm32-unknown-emscripten
Thread model: posix
InstalledDir: E:\GitHub\emsdk\upstream\bin
clang++: note: diagnostic msg: Error generating preprocessed source(s) - no preprocessable inputs.
emcc: error: 'E:/GitHub/emsdk/upstream/bin\clang++.exe -target wasm32-unknown-emscripten -DEMSCRIPTEN -fvisibility=default -mllvm -combiner-global-alias-analysis=false -mllvm -enable-emscripten-sjlj -mllvm -disable-lsr -D__EMSCRIPTEN_major__=3 -D__EMSCRIPTEN_minor__=0 -D__EMSCRIPTEN_tiny__=1 -D_LIBCPP_ABI_VERSION=2 -Werror=implicit-function-declaration -Xclang -iwithsysroot/include/SDL --sysroot=E:\GitHub\emsdk\upstream\emscripten\cache\sysroot -Xclang -iwithsysroot/include\compat -c -g -fwasm-exceptions E:\GitHub\runtimelab\artifacts\tests\coreclr\Browser.wasm.Debug\nativeaot\SmokeTests\Exceptions\Exceptions\native\Exceptions.bc -o E:\GitHub\runtimelab\artifacts\tests\coreclr\Browser.wasm.Debug\nativeaot\SmokeTests\Exceptions\Exceptions\native\Exceptions.o' failed (returned 70)

It is because I start with llvm bitcode?

[sbc100]

This looks like it might be related to #15370. Are you using 3.0.0 (the first version with the fix that issue) or above?

[sbc100]

It looks like the issue relates to -exception-model=wasm not being set when compiling from bitcode with -fwasm-exceptions.

@aheejin, when we do linking we do pass -mllvm -exception-model=wasm .. should that moved to llvm_backend_args() so its passed at compile time too?

[yowl]

Thanks for looking this is 3.0.1-git

[yowl]

You can reproduce this more easily with

emcc -fwasm-exceptions  f:\1.ll

where 1.ll is

; ModuleID = '/mnt/e/1.bc'
source_filename = "e:\\1.c"
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-emscripten"

define hidden i32 @main() #0 {

ret:
  ret i32 0
}

[yowl]

Its a bit strange, clang++ --help makes no mention of wasm-enable-eh or exception-model. clang++ from upstream\bin is clang version 14.0.0 (https://github.com/llvm/llvm-project 5d49511b3058cac17eb80d243d3e2ad5cb0cddb9)

[aheejin]

Thanks for the report! I fixed this in LLVM, so I think you can try this with emsdk install tot soon. It usually takes several hours for LLVM commits to roll out to emsdk. We are planning to do a new release within a few days, so after that, you can also use emsdk install latest.

[yowl]

Thank you very much.

[yowl]

Yep, that now passes command line checks. Fails with my input with

Assertion failed: R == 0 && "Already initialized this value register!", file C:\b\s\w\ir\cache\builder\emscripten-releases\llvm-project\llvm\include\llvm/CodeGen/FunctionLoweringInfo.h, line 209

but I'll have to try to get a repro for that.