因为最近在看《深入理解Java虚拟机 JVM高级特性与最佳实践》，书上介绍了jdk编译的方法，所以进行实践。
目标编译在Windows 11上运行的x64版本OpenJDK 12。
环境准备 系统我的系统是Windows 11，源码中的build.html中对Windows的说明是高于Windows XP的应该都能构建。
Windows XP is not a supported platform, but all newer Windows should be able to build the JDK.OpenJDK 12源码
选择以下任一方法，
- 使用Mercurial clone源码，
hg clone http://hg.openjdk.java.net/jdk/jdk
- 下载源码包。
本文用的是OpenJDK12+33/OpenJDK12-ga，下载的是tar.gz包
md5sum : 760bdd74283e89940f850beb9897bb78 sha1sum : d04d49b05d3152697321b7f98156172233f63b14
下载完成后，建议对比一下md5和sha1摘要，对比主要是为了检查文件是否完整，如果文件不完整，后面执行构建的时候，可能会提示"No rule to make target"的错误[1]。
Boot JDK(Open)JDK 11或12
强烈不建议把JDK放到包含空格的路径下，可以省去一些奇奇怪怪的麻烦。
也不建议放在包含中文的路径下，但因为我没有验证过中文路径，所以不确定会不会出现编码相关的问题。
工具链我使用的是Visual Studio 2017 Community + cygwin 3.3.3-1
同上，强烈不建议把这些程序放到包含空格的路径下，可以省去一些奇奇怪怪的麻烦。
也不建议放在包含中文的路径下，但因为我没有验证过中文路径，所以不确定会不会出现编码相关的问题。
Visual Studio 2017可以在微软官网下了Visual Studio的安装器，安装Visual Studio 2017 Community。
我看到其他博客提到要装英文版本[2,3]，但其实中文版本也是可以的，不过需要修改构建的脚本（我因为很早之前就装了VS，所以就没有装回英文版）。
Cygwin可以在Cygwin官网下载安装器，安装的时候选择autoconf、make、zip和unzip 4个包。
我所选择的版本是，
autoconf 15-1 make 4.2.1-2 zip 3.0-12 unzip 6.0-17
版本不需要选择太新，因为OpenJDK 12已经停止维护了，太新的工具可能不兼容源码的构建脚本。比如，make建议选择4.2.x版本的，4.3版本的对本文所使用的OpenJDK12源码构建有不兼容[4]
安装完后启动Cygwin，程序自动初始化，
Copying skeleton files. These files are for the users to personalise their cygwin experience. They will never be overwritten nor automatically updated. './.bashrc' -> '/home/frank//.bashrc' './.bash_profile' -> '/home/frank//.bash_profile' './.inputrc' -> '/home/frank//.inputrc' './.profile' -> '/home/frank//.profile'
执行cygcheck -d -d来查看安装的包。
$ cygcheck -c -d Cygwin Package Information Package Version _autorebase 001091-1 alternatives 1.3.30c-10 autoconf 15-1 autoconf2.1 2.13-12 autoconf2.5 2.69-5 autoconf2.7 2.71-2 base-cygwin 3.8-1 base-files 4.3-3 bash 4.4.12-3 bzip2 1.0.8-1 ca-certificates 2021.2.52-1 coreutils 8.26-2 crypto-policies 20190218-1 cygutils 1.4.16-7 cygwin 3.3.3-1 dash 0.5.11.5-1 diffutils 3.8-1 editrights 1.03-1 file 5.41-2 findutils 4.8.0-1 gawk 5.1.1-1 getent 2.18.90-4 grep 3.7-2 groff 1.22.4-1 gzip 1.11-1 hostname 3.13-1 info 6.8-2 ipc-utils 1.0-2 less 590-1 libargp 20110921-3 libattr1 2.4.48-2 libblkid1 2.33.1-2 libbz2_1 1.0.8-1 libcrypt0 2.1-1 libcrypt2 4.4.20-1 libdb5.3 5.3.28-2 libfdisk1 2.33.1-2 libffi6 3.2.1-2 libgc1 8.0.6-1 libgcc1 11.2.0-1 libgdbm6 1.18.1-1 libgdbm_compat4 1.18.1-1 libgmp10 6.2.1-2 libguile2.0_22 2.0.14-3 libguile2.2_1 2.2.7-1 libiconv2 1.16-2 libintl8 0.21-1 libltdl7 2.4.6-8 liblz4_1 1.7.5-1 liblzma5 5.2.4-1 libmpfr6 4.1.0-2 libncursesw10 6.1-1.20190727 libp11-kit0 0.23.20-1 libpcre1 8.45-1 libpcre2_8_0 10.39-1 libpipeline1 1.5.3-1 libpopt-common 1.18-1 libpopt0 1.18-1 libreadline7 8.1-2 libsigsegv2 2.10-2 libsmartcols1 2.33.1-2 libssl1.1 1.1.1l-2 libstdc++6 11.2.0-1 libtasn1_6 4.14-1 libunistring2 0.9.10-1 libuuid1 2.33.1-2 login 1.13-1 m4 1.4.19-1 make 4.2.1-2 man-db 2.9.4-2.1 mintty 3.5.2-1 ncurses 6.1-1.20190727 openssl 1.1.1l-2 p11-kit 0.23.20-1 p11-kit-trust 0.23.20-1 perl 5.32.1-2 perl_autorebase 5.32.1-2 perl_base 5.32.1-2 rebase 4.5.0-1 run 1.3.4-2 sed 4.8-1 tar 1.34-1 terminfo 6.1-1.20190727 terminfo-extra 6.1-1.20190727 tzcode 2021e-1 tzdata 2021e-1 unzip 6.0-17 util-linux 2.33.1-2 vim-minimal 8.2.3755-1 which 2.20-2 xz 5.2.4-1 zip 3.0-12 zlib0 1.2.11-1 zstd 1.5.1-1配置
如果是下载tar.gz源码包，则找一个目录解压，
$ tar xzf openjdk12-b67884871b5f.tar.gz $ ls jdk-b67884871b5f openjdk12-b67884871b5f.tar.gz
这个版本的构建脚本有点问题，通过–with-tools-dir来配置Visual Studio的路径不起作用，因为脚本设置的相关变量被清除了[5]，所以需要修改jdk-b67884871b5fmakeautoconftoolchain_windows.m4文件（非官方做法，我只是注释，官方是删掉[6]，不过我只是想说明下，实际上没有区别，可以忽略。这个问题是在OpenJDK12+33之后才改的（通过比对时间发现的），但OpenJDK12已经停止维护了，非LTS）。
# 修改前，205行 VS_ENV_CMD="" # 修改后，205行 #VS_ENV_CMD=""
如果安装的Visual Studio是中文的，具体一点，找到cl.exe，然后执行，检查输出的是否包含中文，
$ /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/Hostx64/x64/cl.exe 用于 x64 的 Microsoft (R) C/C++ 优化编译器 19.16.27045 版 版权所有(C) Microsoft Corporation。保留所有权利。 用法: cl [ 选项... ] 文件名... [ /link 链接选项... ]
如果输出包含中文，跟上面代码片段相似，那么就需要修改jdk-b67884871b5fmakeautoconftoolchain.m4文件（2处），原因是构建脚本判断编译器是否存在，是根据cl.exe等命令的输出做正则判断的，正则表达式匹配的是英文版本，所以上面代码片段的输出无法被默认的表达式识别。
# 修改前，435行
$ECHO "$COMPILER_VERSION_OUTPUT" | $GREP "Microsoft.*Compiler" > /dev/null
# 修改后，435行
$ECHO "$COMPILER_VERSION_OUTPUT" | $GREP "Microsoft.*编译器" > /dev/null
# 修改前，1008-1012行
elif test "x$OPENJDK_TARGET_CPU" = "xx86_64"; then
if test "x$COMPILER_CPU_TEST" != "xx64"; then
AC_MSG_ERROR([Target CPU mismatch. We are building for $OPENJDK_TARGET_CPU but CL is for "$COMPILER_CPU_TEST"; expected "x64".])
fi
fi
# 修改后，1008-1015行，我没有加上x64的判断，只是让脚本知道本地有编译器，语义有变化
elif test "x$OPENJDK_TARGET_CPU" = "xx86_64"; then
if test "x$COMPILER_CPU_TEST" != "xx64"; then
$ECHO "$CC_VERSION_OUTPUT" | $GREP "Microsoft.*编译器" > /dev/null
if test $? -ne 0; then
AC_MSG_ERROR([Target CPU mismatch. We are building for $OPENJDK_TARGET_CPU but CL is for "$COMPILER_CPU_TEST"; expected "x64".])
fi
fi
fi
执行下面命令开始配置，
$ ./configure --enable-debug --disable-warnings-as-errors --with-version-pre=frankcrcBuild --with-boot-jdk=/cygdrive/d/Programs/Java/jdk-11.0.11_windows-x64_bin/jdk-11.0.11/ --with-tools-dir=/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Auxiliary/Build/
| 参数 | 说明 |
|---|---|
| –enabledebug | 表示fastdebug版本，可以调试。 |
| –disable-warnings-as-errors | 表示禁用把警告当做错误的特性，如果不关闭，编译过程中会出错并退出，跟编译器相关。 |
| –with-version-pre | 表示自定义版本信息，我这里指定了frankcrcBuild，后面执行java -version的时候，就会显示出openjdk version "12-frankcrcBuild" 2019-03-19。 |
| –with-boot-jdk | 表示Boot JDk路径，指定到java的上层目录，即bin文件夹所在目录。 |
| –with-tools-dir | 表示Visual Studio路径，指定到vcvars64.bat所在目录，因为脚本会检查这个路径的../..和../../..，vcvars64.bat所在路径能够匹配第二个情况 |
这是我本地执行的结果，执行了15分钟左右，可以参考，
$ ./configure --enable-debug --disable-warnings-as-errors --with-version-pre=frankcrcBuild --with-boot-jdk=/cygdrive/d/Programs/Java/jdk-11.0.11_windows-x64_bin/jdk-11.0.11/ --with-tools-dir=/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Auxiliary/Build/ Runnable configure script is not present Generating runnable configure script at /cygdrive/f/programs/tmp/jdk-b67884871b5f/build/.configure-support/generated-configure.sh Using autoconf at /usr/bin/autoconf [autoconf (GNU Autoconf) 2.71] stdin:222: warning: AC_CHECK_HEADERS($HEADERS_TO_CHECK): you should use literals /mnt/share/cygpkgs/autoconf2.7/autoconf2.7.noarch/src/autoconf-2.71/lib/autoconf/headers.m4:217: AC_CHECK_HEADERS is expanded from... /cygdrive/f/programs/tmp/jdk-b67884871b5f/make/autoconf/libraries.m4:93: LIB_SETUP_LIBRARIES is expanded from... stdin:222: the top level configure: Configuration created at Sun Jan 23 14:56:04 CST 2022. checking for basename... /usr/bin/basename ... checking for cygpath... /usr/bin/cygpath checking for df... /usr/bin/df checking for cpio... no checking for bsdcpio... no checking for nice... /usr/bin/nice checking for pandoc... no checking build system type... x86_64-unknown-cygwin checking host system type... x86_64-unknown-cygwin checking target system type... x86_64-unknown-cygwin checking openjdk-build os-cpu... windows-x86_64 checking openjdk-target os-cpu... windows-x86_64 checking compilation type... native checking cygwin release... 3.3.3(0.341/5/3) checking cygwin root directory as unix-style path... /cygdrive/e/Programs/cygwin64 checking what kind of 'find' is first on the PATH... unix style checking for top-level directory... /cygdrive/f/programs/tmp/jdk-b67884871b5f checking if custom source is suppressed (openjdk-only)... no checking which debug level to use... fastdebug checking which variants of the JVM to build... server checking for sysroot... checking for toolchain path... /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Auxiliary/Build/ checking for extra path... checking where to store configuration... in default location checking what configuration name to use... windows-x86_64-server-fastdebug checking for apt-get... no checking for yum... no checking for brew... no checking for port... no checking for pkgutil... no checking for pkgadd... no checking for gmake... no checking for make... /usr/bin/make configure: Testing potential make at /usr/bin/make, found using make in PATH configure: Using GNU make at /usr/bin/make (version: GNU Make 4.2.1) checking if make --output-sync is supported... yes checking for output-sync value... none checking if find supports -delete... yes checking what type of tar was found... gnu checking that grep (/usr/bin/grep) -Fx handles empty lines in the pattern list correctly... yes checking for unzip... /usr/bin/unzip checking for zip... /usr/bin/zip checking for ldd... /usr/bin/ldd checking for greadelf... no checking for readelf... no checking for dot... no checking for hg... no checking for git... /cygdrive/d/Program Files/Git/cmd/git checking for stat... /usr/bin/stat checking for time... no checking for flock... /usr/bin/flock checking for dtrace... no checking for gpatch... no checking for patch... no checking bash version... 4.4.12 checking if bash supports pipefail... yes checking if bash supports errexit (-e)... yes checking for pkg-config... no checking for default LOG value... checking headless only... no checking for graphviz dot... no, cannot generate full docs checking for pandoc... no, cannot generate full docs checking full docs... no, missing dependencies checking for cacerts file... default checking for jni library path... default checking if packaged modules are kept... yes (default) checking for version string... 12-frankcrcBuild+0-adhoc.frank.jdk-b67884871b5f configure: Found potential Boot JDK using configure arguments checking for Boot JDK... /cygdrive/d/Programs/Java/jdk-11.0.11_windows-x64_bin/jdk-11.0.11/ checking Boot JDK version... java version "11.0.11" 2021-04-20 LTS Java(TM) SE Runtime Environment 18.9 (build 11.0.11+9-LTS-194) Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.11+9-LTS-194, mixed mode) checking for java in Boot JDK... ok checking for javac in Boot JDK... ok checking for javadoc in Boot JDK... ok checking for jar in Boot JDK... ok checking for jarsigner in Boot JDK... ok checking if Boot JDK is 32 or 64 bits... 64 checking for local Boot JDK Class Data Sharing (CDS)... no, creation failed checking for Build JDK... yes, will use output dir configure: Using default toolchain microsoft (Microsoft Visual Studio) checking for link... /usr/bin/link checking if the first found link.exe is actually the Cygwin link tool... yes configure: Found Visual Studio installation at /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Auxiliary/Build//../.. using --with-tools-dir configure: Warning: None of vc/bin/amd64/vcvars64.bat vc/bin/x86_amd64/vcvarsx86_amd64.bat vc/auxiliary/build/vcvarsx86_amd64.bat vc/auxiliary/build/vcvars64.bat were found, Visual Studio installation not recognized. Ignoring configure: Found Visual Studio installation at /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Auxiliary/Build//../../.. using --with-tools-dir configure: Found Microsoft Visual Studio 2017 configure: Rewriting VS_ENV_CMD to "/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/vc/auxiliary/build/vcvarsx86_amd64.bat" configure: Trying to extract Visual Studio environment variables ********************************************************************** ** Visual Studio 2017 Developer Command prompt v15.9.43 ** Copyright (c) 2017 Microsoft Corporation ********************************************************************** [vcvarsall.bat] Environment initialized for: 'x86_x64' configure: Setting extracted environment variables checking for Visual Studio variables... ok configure: Rewriting ipath to "/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/ATLMFC/include" configure: Rewriting ipath to "/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/include" configure: Rewriting ipath to "/cygdrive/c/progra~2/wi3cf2~1/10/include/100183~1.0/ucrt" configure: Rewriting ipath to "/cygdrive/c/progra~2/wi3cf2~1/10/include/100183~1.0/shared" configure: Rewriting ipath to "/cygdrive/c/progra~2/wi3cf2~1/10/include/100183~1.0/um" configure: Rewriting ipath to "/cygdrive/c/progra~2/wi3cf2~1/10/include/100183~1.0/winrt" configure: Rewriting ipath to "/cygdrive/c/progra~2/wi3cf2~1/10/include/100183~1.0/cppwinrt" configure: Rewriting libpath to "/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/ATLMFC/lib/x64" configure: Rewriting libpath to "/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/lib/x64" configure: Rewriting libpath to "/cygdrive/c/progra~2/wi3cf2~1/10/lib/100183~1.0/ucrt/x64" configure: Rewriting libpath to "/cygdrive/c/progra~2/wi3cf2~1/10/lib/100183~1.0/um/x64" checking for cl... no checking for cl... /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl checking resolved symbolic links for CC... no symlink configure: Using microsoft C compiler version 用于 x64 的 Microsoft (R) C/C++ 优化编译器 19.16.27045 版 [用于 x64 的 Microsoft (R) C/C++ 优化编译器 19.16.27045 版] checking whether the C compiler works... yes checking for C compiler default output file name... conftest.exe checking for suffix of executables... .exe checking whether we are cross compiling... no checking for suffix of object files... obj checking whether the compiler supports GNU C... no checking whether /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl accepts -g... yes checking for /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl option to enable C11 features... unsupported checking for /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl option to enable C99 features... unsupported checking for /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl option to enable C89 features... unsupported checking for cl... no checking for cl... /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl checking resolved symbolic links for CXX... no symlink configure: Using microsoft C++ compiler version 用于 x64 的 Microsoft (R) C/C++ 优化编译器 19.16.27045 版 [用于 x64 的 Microsoft (R) C/C++ 优化编译器 19.16.27045 版] checking whether the compiler supports GNU C++... no checking whether /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl accepts -g... yes checking for /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl option to enable C++11 features... none needed configure: WARNING: You are using microsoft older than 16.00.30319.01. This is not a supported configuration. checking how to run the C preprocessor... /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl -E checking how to run the C++ preprocessor... /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl -E checking for link... link configure: Rewriting LD to "/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/link" checking if the found link.exe is actually the Visual Studio linker... yes configure: Using microsoft linker version 14.16.27045.0 [Microsoft (R) Incremental linker Version 14.16.27045.0] checking for lib... lib configure: Rewriting AR to "/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/lib" checking for mt... mt configure: Rewriting MT to "/cygdrive/c/progra~2/wi3cf2~1/10/bin/100183~1.0/x86/mt" checking for rc... rc configure: Rewriting RC to "/cygdrive/c/progra~2/wi3cf2~1/10/bin/100183~1.0/x86/rc" checking for dumpbin... dumpbin configure: Rewriting DUMPBIN to "/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/dumpbin" checking for msbuild.exe... msbuild.exe checking for gobjdump... no checking for objdump... no checking for jtreg... no checking for jtreg test harness... no, not found checking for jmh (Java Microbenchmark Harness)... no, disabled checking for jib... no checking if the C compiler supports "-m64"... yes checking if the C++ compiler supports "-m64"... yes checking if both compilers support "-m64"... yes checking for stdio.h... yes ... checking for target address size... 64 bits checking whether byte ordering is bigendian... no checking if native warnings are errors... no (explicitly set) checking for library containing clock_gettime... no checking what type of native debug symbols to use... external checking for dtrace tool... not found, cannot build dtrace checking for sys/sdt.h... no checking if dtrace should be built... no, missing dependencies checking if Hotspot gtest unit tests should be built... yes checking if fixpath can be created... yes checking if fixpath.exe works... yes configure: Rewriting CYGWIN_VC_INSTALL_DIR to "/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC" POSSIBLE_MSVC_DLL /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Redist/MSVC/14.16.27012/x64/Microsoft.VC141.CRT/vcruntime140.dll configure: Found vcruntime140.dll at /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Redist/MSVC/14.16.27012/x64/Microsoft.VC141.CRT/vcruntime140.dll using well-known location in VCINSTALLDIR checking found vcruntime140.dll architecture... ok checking for vcruntime140.dll... /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Redist/MSVC/14.16.27012/x64/Microsoft.VC141.CRT/vcruntime140.dll configure: Rewriting CYGWIN_VC_INSTALL_DIR to "/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC" POSSIBLE_MSVC_DLL /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Redist/MSVC/14.16.27012/x64/Microsoft.VC141.CRT/msvcp140.dll configure: Found msvcp140.dll at /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Redist/MSVC/14.16.27012/x64/Microsoft.VC141.CRT/msvcp140.dll using well-known location in VCINSTALLDIR checking found msvcp140.dll architecture... ok checking for msvcp140.dll... /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Redist/MSVC/14.16.27012/x64/Microsoft.VC141.CRT/msvcp140.dll checking for UCRT DLL dir... configure: Rewriting CYGWIN_WINDOWSSDKDIR to "/cygdrive/c/progra~2/wi3cf2~1/10" /cygdrive/c/progra~2/wi3cf2~1/10/Redist/ucrt/DLLs/x64 Using freetype: bundled checking for which libjpeg to use... bundled checking for which giflib to use... bundled checking for PNG... checking for which libpng to use... bundled checking for compress in -lz... no checking for which zlib to use... bundled checking for which lcms to use... bundled checking for dlopen in -ldl... no checking if shenandoah can be built... yes checking if zgc can be built... no, platform not supported checking if jvmci module jdk.internal.vm.ci should be built... yes checking if graal module jdk.internal.vm.compiler should be built... yes checking if aot should be enabled... yes checking if cds should be enabled... yes checking if elliptic curve crypto implementation is present... yes checking if jtreg failure handler should be built... no, missing jtreg checking if the CDS classlist generation should be enabled... yes checking if any translations should be excluded... no checking if static man pages should be copied... yes checking if a default CDS archive should be generated... yes checking for number of cores... 12 checking for memory size... 16271 MB checking for appropriate number of jobs to run in parallel... 12 checking flags for boot jdk java command ... -Duser.language=en -Duser.country=US -Xshare:auto checking flags for boot jdk java command for big workloads... -Xms64M -Xmx1600M -XX:ThreadStackSize=1536 checking flags for bootcycle boot jdk java command for big workloads... -Xms64M -Xmx1600M -XX:ThreadStackSize=1536 checking flags for boot jdk java command for small workloads... -XX:+UseSerialGC -Xms32M -Xmx512M -XX:TieredStopAtLevel=1 checking whether to use sjavac... no checking whether to use javac server... yes checking If precompiled header is enabled... yes checking is ccache enabled... no checking if build directory is on local disk... yes checking JVM features for JVM variant 'server'... "aot cds cmsgc compiler1 compiler2 epsilongc g1gc graal jfr jni-check jvmci jvmti management nmt parallelgc serialgc services shenandoahgc vm-structs" configure: creating /cygdrive/f/programs/tmp/jdk-b67884871b5f/build/windows-x86_64-server-fastdebug/configure-support/config.status config.status: creating /cygdrive/f/programs/tmp/jdk-b67884871b5f/build/windows-x86_64-server-fastdebug/spec.gmk config.status: creating /cygdrive/f/programs/tmp/jdk-b67884871b5f/build/windows-x86_64-server-fastdebug/bootcycle-spec.gmk config.status: creating /cygdrive/f/programs/tmp/jdk-b67884871b5f/build/windows-x86_64-server-fastdebug/buildjdk-spec.gmk config.status: creating /cygdrive/f/programs/tmp/jdk-b67884871b5f/build/windows-x86_64-server-fastdebug/compare.sh config.status: creating /cygdrive/f/programs/tmp/jdk-b67884871b5f/build/windows-x86_64-server-fastdebug/Makefile ==================================================== A new configuration has been successfully created in /cygdrive/f/programs/tmp/jdk-b67884871b5f/build/windows-x86_64-server-fastdebug using configure arguments '--enable-debug --disable-warnings-as-errors --with-version-pre=frankcrcBuild --with-boot-jdk=/cygdrive/d/Programs/Java/jdk-11.0.11_windows-x64_bin/jdk-11.0.11/ --with-tools-dir=/cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Auxiliary/Build/'. Configuration summary: * Debug level: fastdebug * HS debug level: fastdebug * JVM variants: server * JVM features: server: 'aot cds cmsgc compiler1 compiler2 epsilongc g1gc graal jfr jni-check jvmci jvmti management nmt parallelgc serialgc services shenandoahgc vm-structs' * OpenJDK target: OS: windows, CPU architecture: x86, address length: 64 * Version string: 12-frankcrcBuild+0-adhoc.frank.jdk-b67884871b5f (12-frankcrcBuild) Tools summary: * Environment: cygwin version 3.3.3(0.341/5/3) (root at /cygdrive/e/Programs/cygwin64) * Boot JDK: java version "11.0.11" 2021-04-20 LTS Java(TM) SE Runtime Environment 18.9 (build 11.0.11+9-LTS-194) Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.11+9-LTS-194, mixed mode) (at /cygdrive/d/Programs/Java/jdk-11.0.11_windows-x64_bin/jdk-11.0.11/) * Toolchain: microsoft (Microsoft Visual Studio 2017) * C Compiler: Version 用于 x64 的 Microsoft (R) C/C++ 优化编译器 19.16.27045 版 (at /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl) * C++ Compiler: Version 用于 x64 的 Microsoft (R) C/C++ 优化编译器 19.16.27045 版 (at /cygdrive/e/Programs/Microsoft/VisualStudio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/HostX86/x64/cl) Build performance summary: * Cores to use: 12 * Memory limit: 16271 MB The following warnings were produced. Repeated here for convenience: WARNING: You are using microsoft older than 16.00.30319.01. This is not a supported configuration.构建
首先要修改一个文件[7,8]，jdk-b67884871b5ftesthotspotgtestutilitiestest_json.cpp，文件是UTF-8编码，里面带有非ASCII字符集的符号，363-373行，可能是linux和windows的差异（编译器对编码处理的差异），Visual Studio编译器处理这样的文件，需要把UTF-8改成UTF-8 BOM，可以在Visual Studio里面，执行 文件->高级保存选项（如果你的Visual Studio里面找不到这个入口，则是默认没有添加到文件菜单下，可以搜索下怎么把命令加上，在自定菜单功能中），
将文件另存为UTF-8（带签名），
当然，也可以使用其他文本编辑工具，如VSCode，Sublime等，或者把357行和下面几行的奇怪的字符修改为其他的字符。
执行make，等待编译完成，我本地编了4个半小时，
make
顺利的话，前后能看到这些，
Building target 'default (exploded-image)' in configuration 'windows-x86_64-server-fastdebug' Warning: No SCM configuration present and no .src-rev ... Compiling 3009 files for java.base ... Compiling 117 files for java.compiler ... Compiling 4 files for BUILD_JIGSAW_TOOLS Stopping sjavac server Finished building target 'default (exploded-image)' in configuration 'windows-x86_64-server-fastdebug'
构建完成后的文件在jdk-b67884871b5fbuildwindows-x86_64-server-fastdebugjdk目录下，执行java.exe -version，就可以看到成果了。
$ build/windows-x86_64-server-fastdebug/jdk/bin/java.exe -version openjdk version "12-frankcrcBuild" 2019-03-19 OpenJDK Runtime Environment (fastdebug build 12-frankcrcBuild+0-adhoc.frank.jdk-b67884871b5f) OpenJDK 64-Bit Server VM (fastdebug build 12-frankcrcBuild+0-adhoc.frank.jdk-b67884871b5f, mixed mode)经验总结
检查源码是否完整。
建议构建的时候，关闭安全软件，部分命令在执行的时候，安全软件可能会提示拦截，如果人不在屏幕旁边的话，可能一不注意，就被自动拒绝，导致过程中断。如果遇到一些文件复制失败，没有权限的，dll失效的问题，可以排除下安全软件的干扰。
强烈不建议把Boot JDK、Visual Studio等工具装在带有空格的路径下，比如检查Boot JDK相关特性的时候，jdk-b67884871b5fmakeautoconfboot-jdk.m4的474行，或者jdk12-b67884871b5fbuild.configure-supportgenerated-configure.sh的64907-64919行，$JAVA是没有使用双引号引用的，如果路径存在空格，在执行java命令的时候，就会提示命令不存在。又比如在脚本在配置Visual Studio相关环境的时候，jdk-b67884871b5fmakeautoconftoolchain_windows.m4的373-403行，或者jdk12-b67884871b5fbuild.configure-supportgenerated-configure.sh的36737-36762行，脚本会取Visutal Studio的脚本执行，执行的命令是没有进行缩写，或unix路径转换的，也没有使用双引号来引用路径，所以执行export命令的时候，变量值就不完整。
configure过程中，把m4文件会被编译成sh脚本，即jdk12-b67884871b5fbuild.configure-supportgenerated-configure.sh，如果遇到文中没有提到的问题，可以在这个文件中查找相关关键字，做一些修改。
直接修改generated-configure.sh，重新执行./conigure ...命令，不会重新生成generated-configure.sh，但是修改m4后再执行./configure ...，会重新生成generated-configure.sh，所以修改的时候需要注意，以免generated-configure.sh重新生成导致修改丢失。
make过程中，我遇到了"模块中不允许使用未命名的包"错误，应该是在使用Boot JDK构建新JDK模块的时候出的问题，可以根据提示，找到对应的java文件（我本地提示的是java文件），看看文件是否完整。我遇到的错误是jdk-b67884871b5fbuildwindows-x86_64-server-fastdebugsupportgensrcjava.basejavaniochannelsNonReadableChannelException.java文件不完整导致的，文件是一个构建过程中自动生成的文件，文件头部的注释少了*/结尾，不知道具体的原因。我的解决方法是，把jdk-b67884871b5fbuildwindows-x86_64-server-fastdebugsupportgensrcjava.base目录删了，然后再次make，目录和下面的文件会重新生成。
可以阅读下源码中的jdk12-b67884871b5fdocbuilding.html文件。
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