x/mobile/cmd/gomobile: build fails: clang80: error: argument unused during compilation: '-stdlib=libc++' [-Werror,-Wunused-command-line-argument]

[alx696]

What version of Go are you using (go version)?

go version go1.11.4 linux/amd64

Android NDK 19.0.5160253-beta2

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GOARCH="amd64"
GOBIN="/home/x/go/bin"
GOCACHE="/home/x/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/x/go"
GOPROXY=""
GORACE=""
GOROOT="/home/x/app/go"
GOTMPDIR=""
GOTOOLDIR="/home/x/app/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build212459853=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Run gomobile build to build an Android APK.

https://github.com/golang/go/wiki/Mobile#building-and-deploying-to-android

What did you expect to see?

Build command will build an APK named basic.apk.

What did you see instead?

x@xpc:~$ gomobile build -target=android golang.org/x/mobile/example/basic
gomobile: go build -buildmode=c-shared -o /tmp/gomobile-work-451339240/lib/armeabi-v7a/libbasic.so golang.org/x/mobile/example/basic failed: exit status 2
# runtime/cgo
clang80: error: argument unused during compilation: '-stdlib=libc++' [-Werror,-Wunused-command-line-argument]

gomobile build -target=android -x golang.org/x/mobile/example/basic Output

x@xpc:~$ gomobile build -target=android -x golang.org/x/mobile/example/basic
GOMOBILE=/home/x/go/pkg/gomobile
WORK=/tmp/gomobile-work-944186541
mkdir -p $WORK/lib/armeabi-v7a
GOOS=android GOARCH=arm CC=$GOMOBILE/ndk-toolchains/arm/bin/arm-linux-androideabi-clang CXX=$GOMOBILE/ndk-toolchains/arm/bin/arm-linux-androideabi-clang++ CGO_ENABLED=1 GOARM=7 go build -x -buildmode=c-shared -o $WORK/lib/armeabi-v7a/libbasic.so golang.org/x/mobile/example/basic
rm -r -f "$WORK"
gomobile: go build -x -buildmode=c-shared -o /tmp/gomobile-work-944186541/lib/armeabi-v7a/libbasic.so golang.org/x/mobile/example/basic failed: exit status 2
WORK=/tmp/go-build950337788
mkdir -p $WORK/b041/
cd /home/x/app/go/src/runtime/cgo
CGO_LDFLAGS='"-g" "-O2" "-llog"' /home/x/app/go/pkg/tool/linux_amd64/cgo -objdir $WORK/b041/ -importpath runtime/cgo -import_runtime_cgo=false -import_syscall=false -exportheader=$WORK/b041/_cgo_install.h -- -I $WORK/b041/ -g -O2 -Wall -Werror ./cgo.go
# runtime/cgo
clang80: error: argument unused during compilation: '-stdlib=libc++' [-Werror,-Wunused-command-line-argument]

[unicameralontology]

I got this same error on go1.11.4 windows/amd64 and NDK 19.0.5232133, and got around it by making this change to an NDK script: https://android-review.googlesource.com/c/platform/ndk/+/875216

--- a/build/tools/make_standalone_toolchain.py
+++ b/build/tools/make_standalone_toolchain.py
@@ -127,7 +127,7 @@
 
     triple = get_triple(arch)
     target = make_clang_target(triple, api)
-    flags = '-target {} -stdlib=libc++'.format(target)
+    flags = '-target {}'.format(target)

and then running gomobile init again.

Seems to be related to this issue in NDK: android/ndk#849

[alx696]

@unicameralontology Thanks! After remove -stdlib=libc++ from path_to_ndk/build/tools/make_standalone_toolchain.py in line 124, error gone away.

[beansgum]

Any way to fix this in CI build?

[wejoy]

When I run：

gomobile bind -target=android testmobile

I got this:

C:\User\GOPATH\bin\gomobile.exe: go build -buildmode=c-shared -o=C:\User\AppData\Local\Temp\gomobile-work-329945059\android\src\main\jniLibs\armeabi-v7a\libgojni.so gobind failed: exit status 2
# runtime/cgo
clang++.exe: error: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated [-Werror,-Wdeprecated]

go version:

go version go1.11.4 windows/amd64

go env:

set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\User\AppData\Local\go-build
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOOS=windows
set GOPATH=C:\User\GOPATH
set GOPROXY=
set GORACE=
set GOROOT=C:\Go
set GOTMPDIR=
set GOTOOLDIR=C:\Go\pkg\tool\windows_amd64
set GCCGO=gccgo
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=C:\User\AppData\Local\Temp\go-build327219370=/tmp/go-build -gno-record-gcc-switches

NDK Version:

19.1.5304403

Does anyone know what's going on?

[beansgum]

I fixed mine some time ago by manually downloading a specific version of ndk where I know I won't encounter this error.

wget -O $ANDROID_HOME/android-ndk-r19b-linux-x86_64.zip https://dl.google.com/android/repository/android-ndk-r19b-linux-x86_64.zip
unzip -qq $ANDROID_HOME/android-ndk-r19b-linux-x86_64.zip -d $ANDROID_HOME/android-ndk-r19b-linux-x86_64
mv $ANDROID_HOME/android-ndk-r19b-linux-x86_64/android-ndk-r19b $ANDROID_HOME/ndk-bundle
export ANDROID_NDK_HOME=$ANDROID_HOME/ndk-bundle

Here's my complete CI script