RFR: 8303796: Optionally build fully statically linked JDK image

[Phil Race]

On Fri, 28 Apr 2023 01:03:28 GMT, Jiangli Zhou <jiangli at openjdk.org> wrote:

> Initial implementation for supporting building a fully statically linked (with a desired set of JDK native libraries and libjvm) Java launcher executable, which is named as 'javastatic'.
> 
> In this PR, the support is only added for the linux platform. Both gcc and clang can be supported. For current demo/testing purpose, the bin/javastatic is statically linked with awt headless and other common JDK native libraries. The current PR doesn't fully handle creating the bundle for a static JDK image, which can be supported later.
> 
> To build the statically linked executable:
> 
> 1. Configure the JDK build with --with-static-java=yes
> 2. Build static-java-image, e.g. 'make jdk-image static-java-image'
> 
>  The 'javastatic' binary created by the static-java-image target is not runnable. The runtime issues will be handled separately.
> 
> Following is a summary of the changes in this PR:
> 
> - Add make/autoconf/static-java.m4 for defining STATIC_JAVA_SETUP. Add STATIC_JAVA_SETUP to make/autoconf/configure.ac.
> 
> - Changes in make/Main.gmk
>   - Add HOTSPOT_VARIANT_STATIC_LIBS_TARGETS and DeclareHotspotStaticLibsRecipe for building libjvm static library.
>   - Add static-java-image for creating the fully statically linked standard Java launcher binary, bin/javastatic. The build process also places libjvm.a into the 'static-libs' image lib/ directory.
> 
> - Add make/StaticLink.gmk, which contains the main support for creating the fully statically linked Java launcher binary.
> 
> - Setup LDFLAGS_CXX_STATIC_JDK based on $TOOLCHAIN_TYPE in make/autoconf/flags-ldflags.m4.
> 
> - Always use bundled libraries for zlib, freetype, etc for static build support. The related changes are in make/autoconf/lib-bundled.m4 and make/autoconf/lib-freetype.m4. Building the bundled zlib, freetype and etc libraries ensures those libraries are included in the JDK binary bundle. It decouples the assumptions/requirements of the static Java image build process from the assumptions/requirements of the JDK build process. A post process that builds the static Java image can use those bundled libraries provided by JDK binary if needed.
> 
> - When building a fully statically linked java launcher executable, the --whole-archive linker option is used for the JDK/VM static libraries to make sure it links every object (.o) file provided by those static libraries. As a result, we need to remove any duplicate object files from the different JDK/VM static libraries. To do that, STATIC_LIB_EXCLUDE_OBJS is added and used in make/common/NativeCompilation.gmk. STATIC_LIB_EXCLUDE_OBJS contains the list of object files that need to be filtered out when creating a specific static library. STATIC_LIB_EXCLUDE_OBJS is defined for JDK/VM static libraries that may contain object files from other libraries (those are needed when building shared libraries), and those object files are added to the STATIC_LIB_EXCLUDE_OBJS. See make/hotspot/lib/CompileJvm.gmk, make/modules/java.base/lib/CoreLibraries.gmk and make/modules/java.desktop/lib/Awt2dLibraries.gmk.
> 
> - In make/common/NativeCompilation.gmk, move the code handling long arguments so that it can be used for the static build support as well.
> 
> - In make/hotspot/lib/CompileJvm.gmk, it specifies to exclude operator_new.o from the libjvm static library. See details in the comment added in CompileJvm.gmk.
> 
> Thanks manc for a bug fix for JAVASTATIC_OBJECT_DIR in StaticLink.gmk.

make/autoconf/lib-freetype.m4 line 118:

> 116:       if test "x${STATIC_JAVA}" = "xtrue"; then
> 117:         AC_MSG_ERROR([--with-freetype=system does not work with --with-static-java=yes])
> 118:       fi

Why not ? Surely you aren't statically linking every library you find on the platform that's referenced by JDK  ?
I mean its fine to say that I'd prefer to statically link this library, but I don't understand the claim that this is the only thing that can work ?

make/modules/java.desktop/lib/Awt2dLibraries.gmk line 229:

> 227:     LIBAWT_XAWT_STATIC_EXCLUDE_OBJS := \
> 228:       debug_assert.o debug_util.o debug_trace.o debug_mem.o systemScale.o
> 229: 

Umm. Does this mean you are linking both headless and xawt into the same image ?
You are on your own with that. Sounds like a mistake to me and I don't want to see any
proposed source code changes to fix up any issues you see later.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13709#discussion_r1180701495
PR Review Comment: https://git.openjdk.org/jdk/pull/13709#discussion_r1180704385