Go link test

This repository aims to show the case which I have found during my development circle. This repo contains only the minimum which reproduces the issue (or perhaps a behavior) with go linker.

The problem

In my project I am using CGO and cross builder feature in order to provide binaries for different platforms (Linux, Mac, Windows). This project has a long story and the approach has been there since go version 1.11.

All of sudden, after go version 1.13 the windows build started throwing at me the error with linking some libraries. After digging a bit deeper in to the problem and setting -v flag to go linker I found out that after 1.13 version Go linker stopped including -lws2_32 & -lwinmm flags to the GCC compiler. It seems that the behavior of linking PE imported libraries has been changed.

Usage

There are two docker images to demonstrate the issue:

• neurostep/go-linker-test:go114 contains go lang version 1.14 and all auxiliary libs and bins;
• neurostep/go-linker-test:go112 contains go lang version 1.12 and all auxiliary libs and bins

By running BUILDER_IMAGE=neurostep/go-linker-test:go112 ./run.sh command, you will get the output similar to the following

$ BUILDER_IMAGE=neurostep/go-linker-test:go112 ./run.sh 
+ exec docker run --rm --user=root -v /Users/maksim-terekhin/my-projects/go-link-test:/srv/src/github.com/Neurostep/go-link-test --entrypoint=/bin/sh neurostep/go-linker-test:go112 -c 'export GOPATH=/srv && cd '\''/srv/src/github.com/Neurostep/go-link-test'\'' && GOARCH=amd64 GOOS=windows CXX="x86_64-w64-mingw32-g++" CC="x86_64-w64-mingw32-gcc -fno-stack-protector -lssp" CGO_ENABLED=1 go install -ldflags "-v -linkmode=external -extldflags '\'' -static -static-libgcc -static-libstdc++'\''  " ./cmd/test '
# github.com/Neurostep/go-link-test/cmd/test
HEADER = -H11 -T0xffffffffffffffff -D0xffffffffffffffff -R0xffffffff
 0.00 deadcode
 0.01 symsize = 0
 0.01 pclntab=272767 bytes, funcdata total 58698 bytes
 0.01 dodata
 0.01 dwarf
 0.02 reloc
 0.03 asmb
 0.03 codeblk
 0.03 rodatblk
 0.03 datblk
 0.03 sym
 0.03 dwarf
 0.03 headr
 0.03 symsize = 0
 0.09 host link: "x86_64-w64-mingw32-gcc" "-m64" "-mconsole" "-o" "/tmp/go-build955574584/b001/exe/a.out.exe" "/tmp/go-link-708938480/go.o" "/tmp/go-link-708938480/000000.o" "/tmp/go-link-708938480/000001.o" "/tmp/go-link-708938480/000002.o" "/tmp/go-link-708938480/000003.o" "/tmp/go-link-708938480/000004.o" "/tmp/go-link-708938480/000005.o" "/tmp/go-link-708938480/000006.o" "/tmp/go-link-708938480/000007.o" "/tmp/go-link-708938480/000008.o" "-g" "-O2" "-L/opt/mingw64/lib" "-lcrypto" "-g" "-O2" "-no-pie" "-static" "-static-libgcc" "-static-libstdc++" "-Wl,-T,/tmp/go-link-708938480/fix_debug_gdb_scripts.ld" "-Wl,--start-group" "-lmingwex" "-lmingw32" "-Wl,--end-group" "-lwinmm" "-lws2_32" "-lkernel32"
 0.27 cpu time
25386 symbols
35076 liveness data

As you might notice, there are flags "-lwinmm" "-lws2_32" printed in the debug info

By running BUILDER_IMAGE=neurostep/go-linker-test:go114 ./run.sh command, you will get the output similar to the following

$ BUILDER_IMAGE=neurostep/go-linker-test:go114 ./run.sh
+ exec docker run --rm --user=root -v /Users/maksim-terekhin/my-projects/go-link-test:/srv/src/github.com/Neurostep/go-link-test --entrypoint=/bin/sh neurostep/go-linker-test:go114 -c 'export GOPATH=/srv && cd '\''/srv/src/github.com/Neurostep/go-link-test'\'' && GOARCH=amd64 GOOS=windows CXX="x86_64-w64-mingw32-g++" CC="x86_64-w64-mingw32-gcc -fno-stack-protector -lssp" CGO_ENABLED=1 go install -ldflags "-v -linkmode=external -extldflags '\'' -static -static-libgcc -static-libstdc++'\''  " ./cmd/test '
# github.com/Neurostep/go-link-test/cmd/test
HEADER = -H10 -T0xffffffffffffffff -R0xffffffff
deadcode
symsize = 0
pclntab=305413 bytes, funcdata total 68666 bytes
symsize = 0
host link: "x86_64-w64-mingw32-gcc" "-m64" "-mconsole" "-Wl,--tsaware" "-Wl,--nxcompat" "-Wl,--major-os-version=6" "-Wl,--minor-os-version=1" "-Wl,--major-subsystem-version=6" "-Wl,--minor-subsystem-version=1" "-o" "/tmp/go-build711421856/b001/exe/a.out.exe" "/tmp/go-link-132502817/go.o" "/tmp/go-link-132502817/000000.o" "/tmp/go-link-132502817/000001.o" "/tmp/go-link-132502817/000002.o" "/tmp/go-link-132502817/000003.o" "/tmp/go-link-132502817/000004.o" "/tmp/go-link-132502817/000005.o" "/tmp/go-link-132502817/000006.o" "/tmp/go-link-132502817/000007.o" "/tmp/go-link-132502817/000008.o" "-g" "-O2" "-L/opt/mingw64/lib" "-lcrypto" "-g" "-O2" "-no-pie" "-static" "-static-libgcc" "-static-libstdc++" "-Wl,-T,/tmp/go-link-132502817/fix_debug_gdb_scripts.ld" "-Wl,--start-group" "-lmingwex" "-lmingw32" "-Wl,--end-group" "-lkernel32"
/usr/local/go/pkg/tool/linux_amd64/link: running x86_64-w64-mingw32-gcc failed: exit status 1
/opt/mingw64/lib/libcrypto.a(b_addr.o):b_addr.c:(.text+0xa1): undefined reference to `__imp_getnameinfo'
/opt/mingw64/lib/libcrypto.a(b_addr.o):b_addr.c:(.text+0xd2): undefined reference to `__imp_ntohs'
/opt/mingw64/lib/libcrypto.a(b_addr.o):b_addr.c:(.text+0x1b9): undefined reference to `gai_strerrorW'
/opt/mingw64/lib/libcrypto.a(b_addr.o):b_addr.c:(.text+0x758): undefined reference to `__imp_freeaddrinfo'
/opt/mingw64/lib/libcrypto.a(b_addr.o):b_addr.c:(.text+0xb58): undefined reference to `__imp_getaddrinfo'
/opt/mingw64/lib/libcrypto.a(b_addr.o):b_addr.c:(.text+0xb95): undefined reference to `gai_strerrorW'
/opt/mingw64/lib/libcrypto.a(b_addr.o):b_addr.c:(.text+0xc93): undefined reference to `__imp_getaddrinfo'
/opt/mingw64/lib/libcrypto.a(b_addr.o):b_addr.c:(.text+0xcd0): undefined reference to `gai_strerrorW'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0xc5): undefined reference to `__imp_WSAStartup'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0xd3): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x266): undefined reference to `__imp_WSAStartup'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x274): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x32d): undefined reference to `__imp_ntohs'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x373): undefined reference to `__imp_getsockopt'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x392): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x3a3): undefined reference to `__imp_gethostbyname'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x3f5): undefined reference to `__imp_WSAStartup'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x3ff): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x47d): undefined reference to `__imp_WSACleanup'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x49a): undefined reference to `__imp_ioctlsocket'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x4b2): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x5ca): undefined reference to `__imp_WSAStartup'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x5d8): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x84d): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x8d5): undefined reference to `__imp_setsockopt'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x908): undefined reference to `__imp_ioctlsocket'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x922): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0x988): undefined reference to `__imp_getsockname'
/opt/mingw64/lib/libcrypto.a(b_sock.o):b_sock.c:(.text+0xa02): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x27): undefined reference to `__imp_socket'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x3f): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0xf1): undefined reference to `__imp_setsockopt'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x11a): undefined reference to `__imp_connect'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x19d): undefined reference to `__imp_setsockopt'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x1ab): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x202): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x254): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x2e2): undefined reference to `__imp_bind'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x302): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x3db): undefined reference to `__imp_getsockopt'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x3f0): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x4c3): undefined reference to `__imp_setsockopt'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x4cd): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x54e): undefined reference to `__imp_bind'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x569): undefined reference to `__imp_listen'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x582): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x5f8): undefined reference to `__imp_setsockopt'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x606): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x67d): undefined reference to `__imp_setsockopt'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x68b): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x6dd): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x765): undefined reference to `__imp_accept'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x79d): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x7fa): undefined reference to `__imp_closesocket'
/opt/mingw64/lib/libcrypto.a(b_sock2.o):b_sock2.c:(.text+0x809): undefined reference to `__imp_closesocket'
/opt/mingw64/lib/libcrypto.a(bss_sock.o):bss_sock.c:(.text+0x1df): undefined reference to `__imp_WSASetLastError'
/opt/mingw64/lib/libcrypto.a(bss_sock.o):bss_sock.c:(.text+0x1f2): undefined reference to `__imp_send'
/opt/mingw64/lib/libcrypto.a(bss_sock.o):bss_sock.c:(.text+0x22a): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(bss_sock.o):bss_sock.c:(.text+0x295): undefined reference to `__imp_WSASetLastError'
/opt/mingw64/lib/libcrypto.a(bss_sock.o):bss_sock.c:(.text+0x2aa): undefined reference to `__imp_send'
/opt/mingw64/lib/libcrypto.a(bss_sock.o):bss_sock.c:(.text+0x2da): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(bss_sock.o):bss_sock.c:(.text+0x34d): undefined reference to `__imp_WSASetLastError'
/opt/mingw64/lib/libcrypto.a(bss_sock.o):bss_sock.c:(.text+0x362): undefined reference to `__imp_recv'
/opt/mingw64/lib/libcrypto.a(bss_sock.o):bss_sock.c:(.text+0x38d): undefined reference to `__imp_WSAGetLastError'
/opt/mingw64/lib/libcrypto.a(bss_sock.o):bss_sock.c:(.text+0x445): undefined reference to `__imp_WSAGetLastError'
collect2: error: ld returned 1 exit status

As you might notice there is linking error, and we can see there is no "-lwinmm" "-lws2_32" provided to the compiler

The workaround

To fix linking problem for Go version 1.13+ we can add corresponding flags to linker via -extldflags

The cause

As a part of security issues fixing process Go stopped implicitly importing ws2_32 & winmm DLL's. Here you can find more details: https://github.com/golang/go/commit/9b6e9f0c8c66355c0f0575d808b32f52c8c6d21c