How to build cpp executable with static libsdtc++.a? -lstdc++ is hardcoded in bazel!!!

[apivovarov]

I'm trying to build @com_google_protobuf//:protoc (in xla project)

The Linker command executed by bazel is

 /usr/bin/gcc @bazel-out/k8-opt/bin/external/com_google_protobuf/protoc-2.params

The last two lines in protoc-2.params are

...
-lstdc++
-lm

I found that these two libs are hardcoded in bazel code in tools/cpp/unix_cc_configure.bzl#L482

What should I do if I want to use static libstdc++.a lib for my executable?

They only way I found so far is to change tools/cpp/unix_cc_configure.bz file and build custom bazel executable.

// Edit tools/cpp/unix_cc_configure.bzl (in def configure_unix_toolchain)

// replace
-lstdc++ 

// with
-l:libstdc++.a

// rebuild bazel
bazel build //src:bazel --compilation_mode=opt

Most probably I missed smth and it should be better option to link with static libstdc++.a.

[fmeum]

These flags are the default if BAZEL_LINKLIBS isn't set. You can set this environment variable (and BAZEL_LINKOPTS) to modify this part of the command line.

[apivovarov]

Great! Thank you! Setting BAZEL_LINKLIBS helped to switch to static libstdc++.a linking!

export BAZEL_LINKLIBS="-l%:libstdc++.a:-lm"

now protoc-2.params has the following 2 lines at the end

...
-l:libstdc++.a
-lm

The only place where I found BAZEL_LINKLIBS description was in 0.28.0 CHANGELOG. Other than that, there's no documentation about BAZEL_LINKLIBS.

  - Bazel's C++ autoconfiguration now understands `BAZEL_LINKLIBS`
    environment variable to specify system libraries that should be
    appended to the link command line.