RFR: 8303796: Optionally build fully statically linked JDK image

[Jiangli Zhou]

On Fri, 28 Apr 2023 18:16:07 GMT, Erik Joelsson <erikj at openjdk.org> wrote:

> I pulled this PR and had a go at building it. For me it failed with errors like this:
> 
> ```
> /home/erik/git/jdk/build/linux-x64/images/static-libs/lib/libjvm.a(os_linux.o):os_linux.cpp:function os::Linux::fast_thread_clock_init(): error: undefined reference to 'clock_getres'
> /home/erik/git/jdk/build/linux-x64/images/static-libs/lib/libjvm.a(os_linux.o):os_linux.cpp:function os::Linux::fast_thread_cpu_time(int): error: undefined reference to 'clock_gettime'
> /home/erik/git/jdk/build/linux-x64/images/static-libs/lib/libjvm.a(os_linux.o):os_linux.cpp:function os::current_thread_cpu_time(): error: undefined reference to 'clock_gettime'
> /home/erik/git/jdk/build/linux-x64/images/static-libs/lib/libjvm.a(os_linux.o):os_linux.cpp:function os::thread_cpu_time(Thread*): error: undefined reference to 'clock_gettime'
> /home/erik/git/jdk/build/linux-x64/images/static-libs/lib/libjvm.a(os_linux.o):os_linux.cpp:function os::current_thread_cpu_time(bool): error: undefined reference to 'clock_gettime'
> /home/erik/git/jdk/build/linux-x64/images/static-libs/lib/libjvm.a(os_linux.o):os_linux.cpp:function os::init_2(): error: undefined reference to 'clock_getres'
> ```
> 
> I haven't dug any deeper to try to figure this out. Is this something you recognize?

Erik, could you please share your `support/native/java.base/java/BUILD_LAUNCHER_javastatic_static_link.cmdline`? This generated .cmdline file contains the static linking command. Here is the linking command from my build:


/usr/bin/gcc -Wl,-z,defs -Wl,-z,relro -Wl,-z,now -Wl,-z,noexecstack -Wl,--hash-style=gnu -m64 -static-libstdc++ -static-libgcc -Wl,-rpath,$ORIGIN/. -Wl,--export-dynamic -o /.../build/linux-x86_64-server-slowdebug/jdk/bin/javastatic /.../linux-x86_64-server-slowdebug/support/native/java.base/java/main.o  -Wl,--whole-archive /.../linux-x86_64-server-slowdebug/images/static-libs/lib/libattach.a ... /.../linux-x86_64-server-slowdebug/images/static-libs/lib/libjvm.a -Wl,--no-whole-archive -lpthread -ldl -lm -l:libstdc++.a


`clock_getres` and the other related symbols are provided by `libc`. For `libc`, we don't static link with. We still use `libc.so`.


$ ldd jdk/bin/javastatic
	linux-vdso.so.1 (0x00007fff8b17a000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f0845321000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f0845140000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f084888d000)



$ objdump -Tw /lib/x86_64-linux-gnu/libc.so.6 | grep clock_getres
00000000000cf260 g    DF .text	0000000000000069  GLIBC_2.17  clock_getres
00000000000cf260 g    DF .text	0000000000000069 (GLIBC_2.2.5) clock_getres

$ nm jdk/bin/javastatic | grep clock_gettime
                 U clock_gettime at GLIBC_2.17
$ nm jdk/bin/javastatic | grep clock_getres
                 U clock_getres at GLIBC_2.17

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PR Comment: https://git.openjdk.org/jdk/pull/13709#issuecomment-1528158982