RFR: 8303796: Optionally build fully statically linked JDK image [v2]

[Jiangli Zhou]

On Sat, 29 Apr 2023 03:57:53 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.
>
> Jiangli Zhou has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use $(JVM_LIBS), which includes -lrt on Linux currently.

> 

Created https://bugs.openjdk.org/browse/JDK-8307194 for the need static library (.a handling) enhancements.

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PR Comment: https://git.openjdk.org/jdk/pull/13709#issuecomment-1530481290