Description
What version of Go are you using (go version)?
go1.12.2
This specifically affects the binary distribution downloaded from golang.org. Bootstrapping 1.12.2 using 1.12.1 did not have this problem.
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="" GOCACHE="/home/bazel/.cache/go-build" GOEXE="" GOFLAGS="" GOHOSTARCH="amd64" GOHOSTOS="linux" GOOS="linux" GOPATH="/home/bazel/go" GOPROXY="" GORACE="" GOROOT="/home/bazel/go1.12.2" GOTMPDIR="" GOTOOLDIR="/home/bazel/go1.12.2/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-build845022667=/tmp/go-build -gno-record-gcc-switches"
This error is most easily reproduced with the gcr.io/bazel-untrusted/ubuntu1404:java8 docker image that Bazel uses for testing. Sorry, it's pretty big.
The important part of this is that it's on ubuntu14.04, which has an older linker.
bazel@269f5850547f:~$ /usr/bin/ld -v
GNU ld (GNU Binutils for Ubuntu) 2.24
bazel@269f5850547f:~$ /usr/bin/ld.gold -v
GNU gold (GNU Binutils for Ubuntu 2.24) 1.11
bazel@269f5850547f:~$ /usr/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/usr/bin/gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.8/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.4-2ubuntu1~14.04.4' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.4)
What did you do?
Download go1.12.2
Try to build the program below:
package main
// const int x = 42;
import "C"
import "fmt"
func main() {
fmt.Println(int(C.x))
}
~/go1.12.2/bin/go build hello.go
What did you expect to see?
Successful build.
What did you see instead?
# command-line-arguments
/home/bazel/go1.12.2/pkg/tool/linux_amd64/link: running gcc failed: exit status 1
/usr/bin/ld: /tmp/go-link-648962525/000005.o: unrecognized relocation (0x2a) in section `.text'
/usr/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
I'm seeing similar error when Bazel links binaries with cgo code.
external/go_sdk/pkg/tool/linux_amd64/link: running /usr/bin/gcc failed: exit status /usr/bin/ld.gold: error: /tmp/go-link-028957856/000005.o: unsupported reloc 42 against global symbol stderr
/usr/bin/ld.gold: error: /tmp/go-link-028957856/000006.o: unsupported reloc 42 against global symbol stderr
/usr/bin/ld.gold: error: /tmp/go-link-028957856/000007.o: unsupported reloc 42 against global symbol x_cgo_threadentry
/usr/bin/ld.gold: error: /tmp/go-link-028957856/000007.o: unsupported reloc 42 against global symbol x_cgo_inittls
/usr/bin/ld.gold: error: /tmp/go-link-028957856/000012.o: unsupported reloc 42 against global symbol stderr
gcc_fatalf.c:17: error: unsupported reloc 42
gcc_libinit.c:29: error: unsupported reloc 42
gcc_linux_amd64.c:86: error: unsupported reloc 42
gcc_linux_amd64.c:52: error: unsupported reloc 42
gcc_util.c:18: error: unsupported reloc 42
collect2: error: ld returned 1 exit status
Other thoughts
@ianlancetaylor told me that reloc 42 is R_X86_64_REX_GOTPCRELX. Support for this was added to gold in 2015, so it's presumably not supported by ubuntu14.04. Support was added to the Go linker for #13114. The Go toolchain should not be emitting these relocs. We may be incorporating .o files produced by a C compiler that emits these on the system that produces the binary distribution.
I was able to work around this by bootstrapping the Go 1.12.2 toolchain locally. I think the C compiler installed on this image does not emit these relocs.