《深入理解JAVA虚拟机 ● 第三版》MacOS编译OpenJDK12

编译环境

• MacOS Catalina 10.15.4
• Xcode 11.5
• command line tools
• Homebrew 2.2.5

编译准备

OpenJDK12源码下载

浏览器打开地址：https://hg.openjdk.java.net/jdk/jdk12/

点击左侧Browse，将显示源码根目录页面：

点击左侧bz2、zip、gz 中任意一个，即可下载压缩好的源码包。

如果下载较慢或者下载失败，可使用百度网盘下载。建议从官网下载，可以获取最新源码。
链接： OpenJDK12源码
提取密码： sbcf

安装JDK11

由于JDK源码中大部分代码还是采用JAVA语言实现，所以在编译前需要准备好另一个编译期可用的JDK，官方称此JDK为Bootstrap JDK。假设需要编译的JDK大版本号为N，我们必须准备好另外一个大版本号至少为N-1的JDK。

安装Xcode

App Store安装

安装command line tools

从App Store上下载的Xcode，默认是不会安装Command Line Tools的，Command Line Tools是在Xcode中的一款工具，可以在命令行中运行C程序。

打开终端，在终端中输入命令

xcode-select --install 

安装完成后，在终端中执行 gcc -v 命令查看是否安装成功。
如果显示如下内容，则安装成功。

Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
Apple clang version 11.0.3 (clang-1103.0.32.62)
Target: x86_64-apple-darwin19.4.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

安装Homebrew

进入Homebrew官网获取最新下载链接；

打开终端，运行拷贝的命令：

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

执行过程中会要求输入密码，输入密码回车继续安装；

安装完成后，会出现 Installation successful! 字样，即安装成功。

终端运行如下命令，可查看安装的版本信息：

brew -v

输出示例：

Homebrew 2.2.5
Homebrew/homebrew-core (git revision e6c5f; last commit 2020-02-09)

安装依赖库

打开终端，执行如下命令：

brew install ccache
brew install freetype
brew install autoconf

编译JDK

编译参数

编译参数可通过在JDK源码目录下执行以下命令查询：

bash  configure --help

查询结果示例如下：

`configure' configures OpenJDK openjdk to adapt to many kinds of systems.

Usage: /Users/fcc/Project/JDKSource/jdk12-06222165c35f/configure [OPTION]... [VAR=VALUE]...

To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE.  See below for descriptions of some of the useful variables.

Defaults for the options are specified in brackets.

Configuration:
  -h, --help              display this help and exit
      --help=short        display options specific to this package
      --help=recursive    display the short help of all the included packages
  -V, --version           display version information and exit
  -q, --quiet, --silent   do not print `checking ...' messages
      --cache-file=FILE   cache test results in FILE [disabled]
  -C, --config-cache      alias for `--cache-file=config.cache'
  -n, --no-create         do not create output files
      --srcdir=DIR        find the sources in DIR [configure dir or `..']

Installation directories:
  --prefix=PREFIX         install architecture-independent files in PREFIX
                          [/usr/local]
  --exec-prefix=EPREFIX   install architecture-dependent files in EPREFIX
                          [PREFIX]

By default, `make install' will install all the files in
`/usr/local/bin', `/usr/local/lib' etc.  You can specify
an installation prefix other than `/usr/local' using `--prefix',
for instance `--prefix=$HOME'.

For better control, use the options below.

Fine tuning of the installation directories:
  --bindir=DIR            user executables [EPREFIX/bin]
  --sbindir=DIR           system admin executables [EPREFIX/sbin]
  --libexecdir=DIR        program executables [EPREFIX/libexec]
  --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
  --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
  --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
  --libdir=DIR            object code libraries [EPREFIX/lib]
  --includedir=DIR        C header files [PREFIX/include]
  --oldincludedir=DIR     C header files for non-gcc [/usr/include]
  --datarootdir=DIR       read-only arch.-independent data root [PREFIX/share]
  --datadir=DIR           read-only architecture-independent data [DATAROOTDIR]
  --infodir=DIR           info documentation [DATAROOTDIR/info]
  --localedir=DIR         locale-dependent data [DATAROOTDIR/locale]
  --mandir=DIR            man documentation [DATAROOTDIR/man]
  --docdir=DIR            documentation root [DATAROOTDIR/doc/openjdk]
  --htmldir=DIR           html documentation [DOCDIR]
  --dvidir=DIR            dvi documentation [DOCDIR]
  --pdfdir=DIR            pdf documentation [DOCDIR]
  --psdir=DIR             ps documentation [DOCDIR]

X features:
  --x-includes=DIR    X include files are in DIR
  --x-libraries=DIR   X library files are in DIR

System types:
  --build=BUILD     configure for building on BUILD [guessed]
  --host=HOST       cross-compile to build programs to run on HOST [BUILD]
  --target=TARGET   configure for building compilers for TARGET [HOST]

Optional Features:
  --disable-option-checking  ignore unrecognized --enable/--with options
  --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
  --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
  --enable-openjdk-only   suppress building custom source even if present
                          [disabled]
  --enable-debug          set the debug level to fastdebug (shorthand for
                          --with-debug-level=fastdebug) [disabled]
  --enable-headless-only  only build headless (no GUI) support [disabled]
  --enable-full-docs      build complete documentation [enabled if all tools
                          found]
  --disable-unlimited-crypto
                          Disable unlimited crypto policy [enabled]
  --disable-keep-packaged-modules
                          Do not keep packaged modules in jdk image [enable]
  --enable-static-build   enable static library build [disabled]
  --disable-warnings-as-errors
                          do not consider native warnings to be an error
                          [enabled]
  --enable-native-coverage
                          enable native compilation with code coverage
                          data[disabled]
  --enable-asan           enable AddressSanitizer if possible [disabled]
  --enable-dtrace[=yes/no/auto]
                          enable dtrace. Default is auto, where dtrace is
                          enabled if all dependencies are present.
  --enable-aot[=yes/no/auto]
                          enable ahead of time compilation feature. Default is
                          auto, where aot is enabled if all dependencies are
                          present.
  --enable-cds[=yes/no/auto]
                          enable class data sharing feature in non-minimal VM.
                          Default is auto, where cds is enabled if supported
                          on the platform.
  --disable-hotspot-gtest Disables building of the Hotspot unit tests
                          [enabled]
  --enable-libffi-bundling
                          enable bundling of libffi.so to make the built JDK
                          runnable on more systems
  --enable-jtreg-failure-handler
                          forces build of the jtreg failure handler to be
                          enabled, missing dependencies become fatal errors.
                          Default is auto, where the failure handler is built
                          if all dependencies are present and otherwise just
                          disabled.
  --disable-generate-classlist
                          forces enabling or disabling of the generation of a
                          CDS classlist at build time. Default is to generate
                          it when either the server or client JVMs are built
                          and enable-cds is true.
  --disable-manpages      Set to disable copy of static man pages [enabled]
  --disable-cds-archive   Set to disable generation of a default CDS archive
                          in the product image [enabled]
  --enable-sjavac         use sjavac to do fast incremental compiles
                          [disabled]
  --disable-javac-server  disable javac server [enabled]
  --enable-icecc          enable distribted compilation of native code using
                          icecc/icecream [disabled]
  --disable-precompiled-headers
                          disable using precompiled headers when compiling C++
                          [enabled]
  --enable-ccache         enable using ccache to speed up recompilations
                          [disabled]

Optional Packages:
  --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
  --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)
  --with-target-bits      build 32-bit or 64-bit binaries (for platforms that
                          support it), e.g. --with-target-bits=32 [guessed]
  --with-debug-level      set the debug level (release, fastdebug, slowdebug,
                          optimized) [release]
  --with-jvm-variants     JVM variants (separated by commas) to build
                          (server,client,minimal,core,zero,custom) [server]
  --with-devkit           use this devkit for compilers, tools and resources
  --with-sys-root         alias for --with-sysroot for backwards compatability
  --with-sysroot          use this directory as sysroot
  --with-tools-dir        alias for --with-toolchain-path for backwards
                          compatibility
  --with-toolchain-path   prepend these directories when searching for
                          toolchain binaries (compilers etc)
  --with-extra-path       prepend these directories to the default path
  --with-sdk-name         use the platform SDK of the given name. [macosx]
  --with-conf-name        use this as the name of the configuration [generated
                          from important configuration options]
  --with-output-sync      set make output sync type if supported by make.
                          [recurse]
  --with-default-make-target
                          set the default make target [exploded-image]
  --with-log              [default vaue for make LOG argument [warn]]
  --with-cacerts-file     specify alternative cacerts file
  --with-copyright-year   Set copyright year value for build [current year]
  --with-jni-libpath      override default JNI library search path
  --with-vendor-name      Set vendor name. Among others, used to set the
                          'java.vendor' and 'java.vm.vendor' system
                          properties. [not specified]
  --with-vendor-url       Set the 'java.vendor.url' system property [not
                          specified]
  --with-vendor-bug-url   Set the 'java.vendor.url.bug' system property [not
                          specified]
  --with-vendor-vm-bug-url
                          Sets the bug URL which will be displayed when the VM
                          crashes [not specified]
  --with-version-string   Set version string [calculated]
  --with-version-pre      Set the base part of the version 'PRE' field
                          (pre-release identifier) ['internal']
  --with-version-opt      Set version 'OPT' field (build metadata)
                          [..]
  --with-version-build    Set version 'BUILD' field (build number) [not
                          specified]
  --with-version-feature  Set version 'FEATURE' field (first number) [current
                          source value]
  --with-version-interim  Set version 'INTERIM' field (second number) [current
                          source value]
  --with-version-update   Set version 'UPDATE' field (third number) [current
                          source value]
  --with-version-patch    Set version 'PATCH' field (fourth number) [not
                          specified]
  --with-version-extra1   Set 1st version extra number [not specified]
  --with-version-extra2   Set 2nd version extra number [not specified]
  --with-version-extra3   Set 3rd version extra number [not specified]
  --with-version-date     Set version date [current source value]
  --with-vendor-version-string
                          Set vendor version string [not specified]
  --with-boot-jdk         path to Boot JDK (used to bootstrap build) [probed]
  --with-boot-jdk-jvmargs specify additional arguments to be passed to Boot
                          JDK tools [none]
  --with-build-jdk        path to JDK of same version as is being built[the
                          newly built JDK]
  --with-import-modules   import a set of prebuilt modules either as a zip
                          file or an exploded directory
  --with-toolchain-type   the toolchain type (or family) to use, use '--help'
                          to show possible values [platform dependent]
  --with-extra-cflags     extra flags to be used when compiling jdk c-files
  --with-extra-cxxflags   extra flags to be used when compiling jdk c++-files
  --with-extra-ldflags    extra flags to be used when linking jdk
  --with-toolchain-version
                          the version of the toolchain to look for, use
                          '--help' to show possible values [platform
                          dependent]
  --with-build-devkit     Devkit to use for the build platform toolchain
  --with-jtreg            Regression Test Harness [probed]
  --with-jmh              Java Microbenchmark Harness for building the OpenJDK
                          Microbenchmark Suite
  --with-jib              Jib dependency management tool [not used]
  --with-macosx-version-max
                          error on use of newer functionality. [macosx]
  --with-abi-profile      specify ABI profile for ARM builds
                          (arm-vfp-sflt,arm-vfp-hflt,arm-sflt,
                          armv5-vfp-sflt,armv6-vfp-hflt,aarch64) [toolchain
                          dependent]
  --with-native-debug-symbols
                          set the native debug symbol configuration (none,
                          internal, external, zipped) [varying]
  --with-jcov             jcov library location
  --with-jcov-input-jdk   jdk image to instrument
  --with-stdc++lib=,,
                          force linking of the C++ runtime on Linux to either
                          static or dynamic, default is static with dynamic as
                          fallback
  --with-msvcr-dll        path to microsoft C runtime dll (msvcr*.dll)
                          (Windows only) [probed]
  --with-msvcp-dll        path to microsoft C++ runtime dll (msvcp*.dll)
                          (Windows only) [probed]
  --with-ucrt-dll-dir     path to Microsoft Windows Kit UCRT DLL dir (Windows
                          only) [probed]
  --with-x                use the X Window System
  --with-cups             specify prefix directory for the cups package
                          (expecting the headers under PATH/include)
  --with-cups-include     specify directory for the cups include files
  --with-fontconfig       specify prefix directory for the fontconfig package
                          (expecting the headers under PATH/include)
  --with-fontconfig-include
                          specify directory for the fontconfig include files
  --with-freetype         specify whether to use 'system' or 'bundled'
                          freetype. Other values are errors. The selected
                          option applies to both build time and run time. The
                          default behaviour can be platform dependent. If
                          using 'system' and either the include files or
                          libraries cannot be located automatically, then
                          additionally specify both using
                          --with-freetype-include and --with-freetype-lib.
  --with-freetype-include specify directory for the freetype include files
  --with-freetype-lib     specify directory for the freetype library
  --with-alsa             specify prefix directory for the alsa package
                          (expecting the libraries under PATH/lib and the
                          headers under PATH/include)
  --with-alsa-include     specify directory for the alsa include files
  --with-alsa-lib         specify directory for the alsa library
  --with-libffi           specify prefix directory for the libffi package
                          (expecting the libraries under PATH/lib and the
                          headers under PATH/include)
  --with-libffi-include   specify directory for the libffi include files
  --with-libffi-lib       specify directory for the libffi library
  --with-libjpeg          use libjpeg from build system or OpenJDK source
                          (system, bundled) [bundled]
  --with-giflib           use giflib from build system or OpenJDK source
                          (system, bundled) [bundled]
  --with-libpng           use libpng from build system or OpenJDK source
                          (system, bundled) [bundled]
  --with-zlib             use zlib from build system or OpenJDK source
                          (system, bundled) [bundled]
  --with-lcms             use lcms2 from build system or OpenJDK source
                          (system, bundled) [bundled]
  --with-graalunit-lib    specify location of 3rd party libraries used by
                          Graal unit tests
  --with-jvm-features     JVM features to enable (foo) or disable (-foo),
                          separated by comma. Use '--help' to show possible
                          values [none]
  --with-with-cpu-port    Deprecated. Option is kept for backwards
                          compatibility and is ignored
  --with-exclude-translations
                          a comma separated list of locales to exclude
                          translations for. Default is to include all
                          translations present in the source.
  --with-num-cores        number of cores in the build system, e.g.
                          --with-num-cores=8 [probed]
  --with-memory-size      memory (in MB) available in the build system, e.g.
                          --with-memory-size=1024 [probed]
  --with-jobs             number of parallel jobs to let make run [calculated
                          based on cores and memory]
  --with-test-jobs        number of parallel tests jobs to run [based on build
                          jobs]
  --with-sjavac-server-java
                          use this java binary for running the sjavac
                          background server [Boot JDK java]
  --with-ccache-dir       where to store ccache files [~/.ccache]

Some influential environment variables:
  BASENAME    Override default value for BASENAME
  BASH        Override default value for BASH
  CAT         Override default value for CAT
  CHMOD       Override default value for CHMOD
  CMP         Override default value for CMP
  COMM        Override default value for COMM
  CP          Override default value for CP
  CUT         Override default value for CUT
  DATE        Override default value for DATE
  DIFF        Override default value for DIFF
  DIRNAME     Override default value for DIRNAME
  ECHO        Override default value for ECHO
  EXPR        Override default value for EXPR
  FILE        Override default value for FILE
  FIND        Override default value for FIND
  HEAD        Override default value for HEAD
  GUNZIP      Override default value for GUNZIP
  GZIP        Override default value for GZIP
  LN          Override default value for LN
  LS          Override default value for LS
  MKDIR       Override default value for MKDIR
  MKTEMP      Override default value for MKTEMP
  MV          Override default value for MV
  NAWK        Override default value for NAWK
  PRINTF      Override default value for PRINTF
  READLINK    Override default value for READLINK
  RM          Override default value for RM
  RMDIR       Override default value for RMDIR
  SH          Override default value for SH
  SORT        Override default value for SORT
  TAIL        Override default value for TAIL
  TAR         Override default value for TAR
  TEE         Override default value for TEE
  TOUCH       Override default value for TOUCH
  TR          Override default value for TR
  UNAME       Override default value for UNAME
  UNIQ        Override default value for UNIQ
  WC          Override default value for WC
  WHICH       Override default value for WHICH
  XARGS       Override default value for XARGS
  AWK         Override default value for AWK
  GREP        Override default value for GREP
  EGREP       Override default value for EGREP
  FGREP       Override default value for FGREP
  SED         Override default value for SED
  CYGPATH     Override default value for CYGPATH
  DF          Override default value for DF
  CPIO        Override default value for CPIO
  NICE        Override default value for NICE
  PANDOC      Override default value for PANDOC
  MAKE        Override default value for MAKE
  UNZIP       Override default value for UNZIP
  ZIPEXE      Override default value for ZIPEXE
  LDD         Override default value for LDD
  READELF     Override default value for READELF
  DOT         Override default value for DOT
  HG          Override default value for HG
  GIT         Override default value for GIT
  STAT        Override default value for STAT
  TIME        Override default value for TIME
  FLOCK       Override default value for FLOCK
  DTRACE      Override default value for DTRACE
  PATCH       Override default value for PATCH
  DSYMUTIL    Override default value for DSYMUTIL
  MIG         Override default value for MIG
  XATTR       Override default value for XATTR
  CODESIGN    Override default value for CODESIGN
  SETFILE     Override default value for SETFILE
  ELFEDIT     Override default value for ELFEDIT
  PKG_CONFIG  path to pkg-config utility
  JAVA        Override default value for JAVA
  JAVAC       Override default value for JAVAC
  JAVADOC     Override default value for JAVADOC
  JAR         Override default value for JAR
  JARSIGNER   Override default value for JARSIGNER
  CC          C compiler command
  CFLAGS      C compiler flags
  LDFLAGS     linker flags, e.g. -L if you have libraries in a
              nonstandard directory 
  LIBS        libraries to pass to the linker, e.g. -l
  CPPFLAGS    (Objective) C/C++ preprocessor flags, e.g. -I if
              you have headers in a nonstandard directory 
  CXX         C++ compiler command
  CXXFLAGS    C++ compiler flags
  CPP         C preprocessor
  CXXCPP      C++ preprocessor
  AS          Override default value for AS
  AR          Override default value for AR
  LIPO        Override default value for LIPO
  OTOOL       Override default value for OTOOL
  INSTALL_NAME_TOOL
              Override default value for INSTALL_NAME_TOOL
  STRIP       Override default value for STRIP
  NM          Override default value for NM
  GNM         Override default value for GNM
  OBJCOPY     Override default value for OBJCOPY
  OBJDUMP     Override default value for OBJDUMP
  CXXFILT     Override default value for CXXFILT
  BUILD_CC    Override default value for BUILD_CC
  BUILD_CXX   Override default value for BUILD_CXX
  BUILD_NM    Override default value for BUILD_NM
  BUILD_AR    Override default value for BUILD_AR
  BUILD_OBJCOPY
              Override default value for BUILD_OBJCOPY
  BUILD_STRIP Override default value for BUILD_STRIP
  JTREGEXE    Override default value for JTREGEXE
  XMKMF       Path to xmkmf, Makefile generator for X Window System
  FREETYPE_CFLAGS
              C compiler flags for FREETYPE, overriding pkg-config
  FREETYPE_LIBS
              linker flags for FREETYPE, overriding pkg-config
  ALSA_CFLAGS C compiler flags for ALSA, overriding pkg-config
  ALSA_LIBS   linker flags for ALSA, overriding pkg-config
  LIBFFI_CFLAGS
              C compiler flags for LIBFFI, overriding pkg-config
  LIBFFI_LIBS linker flags for LIBFFI, overriding pkg-config
  PNG_CFLAGS  C compiler flags for PNG, overriding pkg-config
  PNG_LIBS    linker flags for PNG, overriding pkg-config
  LCMS_CFLAGS C compiler flags for LCMS, overriding pkg-config
  LCMS_LIBS   linker flags for LCMS, overriding pkg-config
  ICECC_CMD   Override default value for ICECC_CMD
  ICECC_CREATE_ENV
              Override default value for ICECC_CREATE_ENV
  ICECC_WRAPPER
              Override default value for ICECC_WRAPPER
  CCACHE      Override default value for CCACHE

Use these variables to override the choices made by `configure' or to help
it to find libraries and programs with nonstandard names/locations.

Report bugs to <[email protected]>.
OpenJDK home page: <http://openjdk.java.net>.

Additional (non-autoconf) OpenJDK Options:
  --openjdk-target=TARGET cross-compile with TARGET as target platform
                          (i.e. the one you will run the resulting binary on).
                          Equivalent to --host=TARGET --target=TARGET
                          --build=<current platform>
  --debug-configure       Run the configure script with additional debug
                          logging enabled.

The following toolchains are available as arguments to --with-toolchain-type.
Which are valid to use depends on the build platform.
  gcc         GNU Compiler Collection
  clang       clang/LLVM
  solstudio   Oracle Solaris Studio
  xlc         IBM XL C/C++
  microsoft   Microsoft Visual Studio

The following JVM features are available as arguments to --with-jvm-features.
Which are valid to use depends on the target platform.
  compiler1 compiler2 zero minimal dtrace jvmti jvmci graal vm-structs jni-check services management cmsgc epsilongc g1gc parallelgc serialgc shenandoahgc zgc nmt cds static-build link-time-opt aot jfr 

Please be aware that, when cross-compiling, the OpenJDK configure script will
generally use 'target' where autoconf traditionally uses 'host'.

Also note that variables must be passed on the command line. Variables in the
environment will generally be ignored, unlike traditional autoconf scripts.

• --with-debug-level=：设置编译的级别，可选值为release、fastdebug、slowdebug、越往后进行的优化措施就越少，带的调试信息就越多。默认值为release。--enable-debug：等效与--with-debug-level=fastdebug。
• --with-jvm-variants=[]：编译特定模式（Variants）的HotSpot虚拟机，可以多个模式并存，可选值有server、client、minimal、core、zero、custom、。

执行编译

如编译FastDebug版、仅含Server模式 的HorSpot虚拟机，步骤如下：

执行如下命令，对编译过程中的依赖项、参数、输出目录进行检查和构建，如果编译过程中需要的工具链或者依赖项有缺失，根据命令行提示进行安装。

bash configure --enable-debug --with-jvm-variants=server

如果环境一切正常，会提示如下信息：

Configuration summary:
* Debug level:    fastdebug
* HS debug level: fastdebug
* JVM variants:   server
* JVM features:   server: 'aot cds cmsgc compiler1 compiler2 dtrace epsilongc g1gc graal jfr jni-check jvmci jvmti management nmt parallelgc serialgc services shenandoahgc vm-structs' 
* OpenJDK target: OS: macosx, CPU architecture: x86, address length: 64
* Version string: 12-internal+0-adhoc.fcc.jdk12-06222165c35f (12-internal)

Tools summary:
* Boot JDK:       java version "12.0.2" 2019-07-16 Java(TM) SE Runtime Environment (build 12.0.2+10) Java HotSpot(TM) 64-Bit Server VM (build 12.0.2+10, mixed mode, sharing)  (at /Library/Java/JavaVirtualMachines/jdk-12.0.2.jdk/Contents/Home)
* Toolchain:      clang (clang/LLVM from Xcode 11.5)
* C Compiler:     Version 11.0.3 (at /usr/bin/clang)
* C++ Compiler:   Version 11.0.3 (at /usr/bin/clang++)

Build performance summary:
* Cores to use:   12
* Memory limit:   16384 MB

操作成功之后，执行编译命令：

make images

$注意：上述步骤如果出现异常或者后，再次执行前需要先执行命令清理./bulid编译目录：$

make clean

make dist-clean

正常编译完成后，可在命令行看到成功命令输出：

Finished building target 'images' in configuration 'macosx-x86_64-server-fastdebug'

至此，OpenJDK12编译完成。

查看JDK信息

命令行移动当前位置至jdk12-06222165c35f/build/macosx-x86_64-server-fastdebug/jdk目录下，执行./bin/java -version，可查询编译的JDK版本信息。此目录可打包直接作为完整的JDK进行使用。

openjdk version "12-internal" 2019-03-19
OpenJDK Runtime Environment (fastdebug build 12-internal+0-adhoc.fcc.jdk12-06222165c35f)
OpenJDK 64-Bit Server VM (fastdebug build 12-internal+0-adhoc.fcc.jdk12-06222165c35f, mixed mode)

编译失败问题

在笔者编译的过程中，出现过如下的错误：

ERROR: Build failed for target 'images' in configuration 'macosx-x86_64-client-fastdebug' (exit code 2) 
Stopping sjavac server

=== Output from failing command(s) repeated here ===
* For target hotspot_variant-client_libjvm_gtest_objs_test_symbolTable.o:
/Users/fcc/Project/JDKSource/jdk12-06222165c35f/test/hotspot/gtest/classfile/test_symbolTable.cpp:62:6: error: explicitly assigning value of variable of type 'TempNewSymbol' to itself [-Werror,-Wself-assign-overloaded]
  s1 = s1; // self assignment
  ~~ ^ ~~
1 error generated.

* All command lines available in /Users/fcc/Project/JDKSource/jdk12-06222165c35f/build/macosx-x86_64-client-fastdebug/make-support/failure-logs.
=== End of repeated output ===

No indication of failed target found.
Hint: Try searching the build log for '] Error'.
Hint: See doc/building.html#troubleshooting for assistance.

make[1]: *** [main] Error 2
make: *** [images] Error 2

根据日志提示找到了dk12-06222165c35f/test/hotspot/gtest/classfile目录下的test_symbolTable.cpp 文件，跳转第62行，内容如下：

此行我直接将其注释掉了。

保存之后执行清理命令，重新编译。