enhancement: please ignore the empty -J [was] grpc-dlang build failure with ldc2 #3723

mw66 · 2021-05-16T15:50:35Z

dub build --compiler=ldc2 fails with many undefined reference errors.

...
Performing "debug" build using ldc2 for x86_64.
grpc 0.4.0-beta.1: building configuration "library"...
/usr/lib/gcc/x86_64-linux-gnu/10/../../../x86_64-linux-gnu/Scrt1.o:function _start: error: undefined reference to 'main'
/home/user/grpc-dlang/source/grpc/GrpcStream.d:85: error: undefined reference to '_D4hunt2io11BufferUtilsQn8toStringFCQBiQBg10ByteBufferQmZAya'
/home/user/grpc-dlang/../.dub/packages/hunt-1.7.7/hunt/source/hunt/logging/Logger.d-mixin-584:584: error: undefined reference to '_D4hunt7logging6Logger8g_loggerCQBeQBcQxQz'
...

Following instructions on

https://github.com/huntlabs/grpc-dlang

readme, dub build i.e. DMD works fine. The build file is very simple, nothing suspicious:

https://github.com/huntlabs/grpc-dlang/blob/master/dub.json

Could this be ldc problem?

The text was updated successfully, but these errors were encountered:

JohanEngelen · 2021-05-16T17:03:35Z

Please distill down to the essence of this problem within the grpc-dlang project first. It could just as well be a dub bug. (the dlang forums may also be able to help)

kinke · 2021-05-22T19:08:34Z

It might be worth trying dub build --compiler=ldmd2 - if ldmd2 works, it's a dub thing. Running dub with -v shows the compiler command-lines, which can be compared across dmd and ldc2. That 'no main()' error sounds a bit like https://forum.dlang.org/post/s895he$1mbm$1@digitalmars.com, so make sure to use the same dub version when testing with dmd.

mw66 · 2021-05-22T19:52:24Z

Tried, same error:

$ dub build --compiler=ldmd2
Performing "debug" build using ldmd2 for x86_64.
grpc 0.4.0-beta.1: building configuration "library"...
/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/Scrt1.o:function _start: error: undefined reference to 'main'
...

Also tried ldc2's dub

$ ~/project/ldc2/bin/dub build --compiler=ldmd2
Performing "debug" build using ldmd2 for x86_64.
grpc 0.4.0-beta.1: building configuration "library"...
/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/Scrt1.o:function _start: error: undefined reference to 'main'
...

mw66 · 2021-05-22T20:00:24Z

and I also compared the exact cmd with -v:

~/project/ldc2/bin/dub build -v --compiler=ldmd2  // same build error above
~/project/ldc2/bin/dub build -v --compiler=dmd   //  successful build

except the output file name i.e -of..., there is no difference:

ldmd2 -J -lib -of.dub/build/library-debug-linux.posix-x86_64-ldc_v1.26.0-C3E1A3C9CD32A6FC331A53471EAF68DB/libgrpc.a -debug -g -w -version=Have_grpc -version=Have_hunt_http -version=Have_protobuf -version=Have_hunt_net -version=Have_hunt_extra -version=Have_hunt -version=HAVE_EPOLL -Isource/ -I../../../.dub/packages/hunt-http-0.7.3/hunt-http/source/ -I../../../.dub/packages/hunt-net-0.6.6/hunt-net/source/ -I../../../.dub/packages/hunt-extra-1.1.3/hunt-extra/source/ -I../../../.dub/packages/hunt-1.7.7/hunt/source/ -I../../../.dub/packages/protobuf-0.6.2/protobuf/src/ -J../../../.dub/packages/hunt-extra-1.1.3/hunt-extra/resources source/grpc/EvBuffer.d source/grpc/GrpcClient.d source/grpc/GrpcCode.d source/grpc/GrpcException.d source/grpc/GrpcServer.d source/grpc/GrpcService.d source/grpc/GrpcStream.d source/grpc/Status.d source/grpc/StatusCode.d source/grpc/package.d source/grpc/stream/ClientReader.d source/grpc/stream/ClientReaderWriter.d source/grpc/stream/ClientWriter.d source/grpc/stream/ServerReader.d source/grpc/stream/ServerReaderWriter.d source/grpc/stream/ServerWriter.d -vcolumns

dmd -J -lib -of.dub/build/library-debug-linux.posix-x86_64-dmd_v2.095.1-70FB875C140F8BEFB2515B2EEE9739D1/libgrpc.a -debug -g -w -version=Have_grpc -version=Have_hunt_http -version=Have_protobuf -version=Have_hunt_net -version=Have_hunt_extra -version=Have_hunt -version=HAVE_EPOLL -Isource/ -I../../../.dub/packages/hunt-http-0.7.3/hunt-http/source/ -I../../../.dub/packages/hunt-net-0.6.6/hunt-net/source/ -I../../../.dub/packages/hunt-extra-1.1.3/hunt-extra/source/ -I../../../.dub/packages/hunt-1.7.7/hunt/source/ -I../../../.dub/packages/protobuf-0.6.2/protobuf/src/ -J../../../.dub/packages/hunt-extra-1.1.3/hunt-extra/resources source/grpc/EvBuffer.d source/grpc/GrpcClient.d source/grpc/GrpcCode.d source/grpc/GrpcException.d source/grpc/GrpcServer.d source/grpc/GrpcService.d source/grpc/GrpcStream.d source/grpc/Status.d source/grpc/StatusCode.d source/grpc/package.d source/grpc/stream/ClientReader.d source/grpc/stream/ClientReaderWriter.d source/grpc/stream/ClientWriter.d source/grpc/stream/ServerReader.d source/grpc/stream/ServerReaderWriter.d source/grpc/stream/ServerWriter.d -vcolumns

So, could this be a LDC bug? @kinke

kinke · 2021-05-22T20:10:47Z

This is the wrong command - this creates a static library with -lib, no linking happening yet.

mw66 · 2021-05-22T20:26:00Z

What do you mean by "wrong command"?

It is building a library: (I specifically added: "targetType": "library" to the dub.json)

~/project/contrib/grpc-dlang 16:22:36$ cat dub.json 
{
    "name": "grpc",
    "targetType": "library",
    "license": "Apache-2.0",
    "copyright": "Copyright (C) 2018-2021 HuntLabs",
    "homepage": "https://www.huntlabs.net",
    "description": "gRPC implementation for D programming language",
    "dependencies": {
        "hunt-http": "~>0.7.0",
        "protobuf": "~>0.6.2"
    }
}

with this same dub.json file,

~/project/ldc2/bin/dub build -v --compiler=ldmd2  // same build error above
~/project/ldc2/bin/dub build -v --compiler=dmd   //  successful build

This is what the build errors I showed above.

Can you try it yourself?

kinke · 2021-05-22T21:08:25Z

Can you try it yourself?

Sorry but no, looks too time-consuming and hardly LDC's fault.

What do you mean by "wrong command"?

The error is emitted by the linker. The linker isn't invoked by LDC with -lib. So either dub isn't printing the actual failing command-line, or you've just missed it.

mw66 · 2021-05-22T21:28:18Z

I don't think I missed it, and I copied the 1 line before the command (it says: building configuration "library"), and 1 line after the command (it's the error: undefined reference to 'main')

I didn't see any linker command:

grpc 0.4.0-beta.1: building configuration "library"...
ldmd2 -J -lib -of.dub/build/library-debug-linux.posix-x86_64-ldc_v1.26.0-C3E1A3C9CD32A6FC331A53471EAF68DB/libgrpc.a -debug -g -w -version=Have_grpc -version=Have_hunt_http -version=Have_protobuf -version=Have_hunt_net -version=Have_hunt_extra -version=Have_hunt -version=HAVE_EPOLL -Isource/ -I../../../.dub/packages/hunt-http-0.7.3/hunt-http/source/ -I../../../.dub/packages/hunt-net-0.6.6/hunt-net/source/ -I../../../.dub/packages/hunt-extra-1.1.3/hunt-extra/source/ -I../../../.dub/packages/hunt-1.7.7/hunt/source/ -I../../../.dub/packages/protobuf-0.6.2/protobuf/src/ -J../../../.dub/packages/hunt-extra-1.1.3/hunt-extra/resources source/grpc/EvBuffer.d source/grpc/GrpcClient.d source/grpc/GrpcCode.d source/grpc/GrpcException.d source/grpc/GrpcServer.d source/grpc/GrpcService.d source/grpc/GrpcStream.d source/grpc/Status.d source/grpc/StatusCode.d source/grpc/package.d source/grpc/stream/ClientReader.d source/grpc/stream/ClientReaderWriter.d source/grpc/stream/ClientWriter.d source/grpc/stream/ServerReader.d source/grpc/stream/ServerReaderWriter.d source/grpc/stream/ServerWriter.d -vcolumns
/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/Scrt1.o:function _start: error: undefined reference to 'main'

mw66 · 2021-05-22T21:40:30Z

@kinke Hi, I realized that I have that exact command line, so I just run that ldmd2 command directly (without using dub):

"""
$ ldmd2 -J -lib -of.dub/build/library-debug-linux.posix-x86_64-ldc_v1.26.0-C3E1A3C9CD32A6FC331A53471EAF68DB/libgrpc.a -debug -g -w -version=Have_grpc -version=Have_hunt_http -version=Have_protobuf -version=Have_hunt_net -version=Have_hunt_extra -version=Have_hunt -version=HAVE_EPOLL -Isource/ -I../../../.dub/packages/hunt-http-0.7.3/hunt-http/source/ -I../../../.dub/packages/hunt-net-0.6.6/hunt-net/source/ -I../../../.dub/packages/hunt-extra-1.1.3/hunt-extra/source/ -I../../../.dub/packages/hunt-1.7.7/hunt/source/ -I../../../.dub/packages/protobuf-0.6.2/protobuf/src/ -J../../../.dub/packages/hunt-extra-1.1.3/hunt-extra/resources source/grpc/EvBuffer.d source/grpc/GrpcClient.d source/grpc/GrpcCode.d source/grpc/GrpcException.d source/grpc/GrpcServer.d source/grpc/GrpcService.d source/grpc/GrpcStream.d source/grpc/Status.d source/grpc/StatusCode.d source/grpc/package.d source/grpc/stream/ClientReader.d source/grpc/stream/ClientReaderWriter.d source/grpc/stream/ClientWriter.d source/grpc/stream/ServerReader.d source/grpc/stream/ServerReaderWriter.d source/grpc/stream/ServerWriter.d -vcolumns

/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/Scrt1.o:function _start: error: undefined reference to 'main'

...
"""

Same error!

So it is LDC with -lib who is invoking the linker!

Can you check!

mw66 · 2021-05-22T22:01:14Z

I also tried to run the exact command generated by $ ~/project/ldc2/bin/dub build -v --compiler=ldc2, directly without using dub,

Same error:

$ ldc2 -J -lib -of.dub/build/library-debug-linux.posix-x86_64-ldc_v1.26.0-9DDFB54AD65F3A8BD307F1E232CC37B2/libgrpc.a -d-debug -g -w --oq -od=.dub/build/library-debug-linux.posix-x86_64-ldc_v1.26.0-9DDFB54AD65F3A8BD307F1E232CC37B2//obj -d-version=Have_grpc -d-version=Have_hunt_http -d-version=Have_protobuf -d-version=Have_hunt_net -d-version=Have_hunt_extra -d-version=Have_hunt -d-version=HAVE_EPOLL -Isource/ -I../../../.dub/packages/hunt-http-0.7.3/hunt-http/source/ -I../../../.dub/packages/hunt-net-0.6.6/hunt-net/source/ -I../../../.dub/packages/hunt-extra-1.1.3/hunt-extra/source/ -I../../../.dub/packages/hunt-1.7.7/hunt/source/ -I../../../.dub/packages/protobuf-0.6.2/protobuf/src/ -J../../../.dub/packages/hunt-extra-1.1.3/hunt-extra/resources source/grpc/EvBuffer.d source/grpc/GrpcClient.d source/grpc/GrpcCode.d source/grpc/GrpcException.d source/grpc/GrpcServer.d source/grpc/GrpcService.d source/grpc/GrpcStream.d source/grpc/Status.d source/grpc/StatusCode.d source/grpc/package.d source/grpc/stream/ClientReader.d source/grpc/stream/ClientReaderWriter.d source/grpc/stream/ClientWriter.d source/grpc/stream/ServerReader.d source/grpc/stream/ServerReaderWriter.d source/grpc/stream/ServerWriter.d -vcolumns
/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/Scrt1.o:function _start: error: undefined reference to 'main'
...

kinke · 2021-05-23T11:29:34Z

Thx for testing further - after a 2nd look, it looks like -J -lib is the problem. LDC accepts -Jmy/dir as well as -J my/dir, so an empty/invalid -J swallows the consecutive -lib arg.

mw66 · 2021-05-23T15:16:18Z

Ha! Great to find the problem!

mw66 · 2021-05-23T16:31:04Z

@kinke

I've update the dub ticket: dlang/dub#2133, and hopefully dub will fix it not to pass empty -J.

On the other hand, IIRC LDC share the same front end code with DMD, so looks like DMD choose to ignore the empty -J, I'm wondering if LDC can use this same defensive approach too? this will make the LDC compiler more robust.

Thanks.

kinke · 2021-06-27T03:32:57Z

DMD doesn't ignore an empty -J, it then adds an empty entry to its string import paths - I suspect with semantics being identical to -J. (include current working dir): https://github.com/dlang/dmd/blob/904360af0edeb894f2ecc1c49770874885d400fd/src/dmd/mars.d#L2295-L2300

We cannot alter this behavior for ldc2, because this is how LLVM cmdline options work (and would be a breaking change), but we could make ldmd2 compatible with DMD, translating -J to -J. (and probably the same for -I).

mw66 · 2021-06-27T03:42:02Z

That will be fine. Thanks.

mw66 · 2023-04-04T17:58:52Z

Since dlang/dub#2133 is fixed, and closed.

Gonna close this, feel free to reopen if you have another reproduction case.

mw66 mentioned this issue May 16, 2021

dub generate empty/invalid -J [was: grpc-dlang build failure with ldc2] dlang/dub#2133

Closed

mw66 changed the title ~~grpc-dlang build failure with ldc2~~ enhancement: please ignore the empty -J [was] grpc-dlang build failure with ldc2 Jun 4, 2021

mw66 closed this as completed Apr 4, 2023

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enhancement: please ignore the empty -J [was] grpc-dlang build failure with ldc2 #3723

enhancement: please ignore the empty -J [was] grpc-dlang build failure with ldc2 #3723

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enhancement: please ignore the empty -J [was] grpc-dlang build failure with ldc2 #3723

enhancement: please ignore the empty -J [was] grpc-dlang build failure with ldc2 #3723

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