JVM之编译OpenJDK
学习JVM时看到书里讲到自己编译OpenJDK。记录一下过程
- Mac系统版本：High Sierra 10.13.6
- 源码版本：jdk8u-dev
一、准备源码
我是从官网下载网站的，openJDK源码是用mercurial进行管理的，所以首先使用homebrew安装mercurial
brew install mercurial
安装完成之后，再运行命令克隆jdk源码，之后通过运行脚本get_source.sh获取所有的源代码
hg clone http://hg.openjdk.java.net/jdk8u/jdk8u-dev/ cd jdk8u-dev sh ./get_source.sh
在获取源码的过程中可能会遇到一些问题，如下所示。我遇到的问题主要是网络的问题，后来通过切换网络，使用手机热点解决了。
abort: stream ended unexpectedly (got 1596 bytes, expected 10164)
二、设置环境变量
在编译开始之前需要设置一些变量。这里与书中所讲的有一些不一样，只因为我用的是Mac平台，所以编译器之类的可能会有一些不一样。可以将下面的内容拷贝建立一个脚本运行。
这里的环境变量设置采用了博客https://www.jianshu.com/p/d9a1e1072f37中的设置
# 语言选项 export LANG=C # Mac平台，C编译器不再是GCC，是clang export CC=clang # 跳过clang的一些严格的语法检查，不然会将N多的警告作为Error export COMPILER_WARNINGS_FATAL=false # 链接时使用的参数 export LFLAGS='-Xlinker -lstdc++' # 是否使用clang export USE_CLANG=true # 使用64位数据模型 export LP64=1 # 告诉编译平台是64位，不然会按32位来编译 export ARCH_DATA_MODEL=64 # 允许自动下载依赖 export ALLOW_DOWNLOADS=true # 并行编译的线程数，编译时间长，为了不影响其他工作，我选择为2 export HOTSPOT_BUILD_JOBS=2 # 是否跳过与先前版本的比较 export SKIP_COMPARE_IMAGES=true # 是否使用预编译头文件，加快编译速度 export USE_PRECOMPILED_HEADER=true # 是否使用增量编译 export INCREMENTAL_BUILD=true # 编译内容 export BUILD_LANGTOOLS=true export BUILD_JAXP=true export BUILD_JAXWS=true export BUILD_CORBA=true export BUILD_HOTSPOT=true export BUILD_JDK=true # 编译版本 export SKIP_DEBUG_BUILD=true export SKIP_FASTDEBUG_BUILD=false export DEBUG_NAME=debug # 避开javaws和浏览器Java插件之类的部分的build export BUILD_DEPLOY=false export BUILD_INSTALL=false unset JAVA_HOME
三、编译
设置好环境变量之后，就可以开始编译了，首先运行configure，这个脚本会调用很多其他的脚本进行配置并检查编译环境。
bash ./configure
运行成功后的显示如下：
A new configuration has been successfully created in /Users/zhengshuangxi/mercurial/temp/build/macosx-x86_64-normal-server-release using default settings. Configuration summary: * Debug level: release * JDK variant: normal * JVM variants: server * OpenJDK target: OS: macosx, CPU architecture: x86, address length: 64 Tools summary: * Boot JDK: java version "1.8.0_212" Java(TM) SE Runtime Environment (build 1.8.0_212-b10) Java HotSpot(TM) 64-Bit Server VM (build 25.212-b10, mixed mode) (at /Library/Java/JavaVirtualMachines/jdk1.8.0_212.jdk/Contents/Home) * Toolchain: gcc (GNU Compiler Collection) * C Compiler: Version Apple LLVM version 10.0.0 (clang-1000.11.45.5) Target: x86_64-apple-darwin17.7.0 Thread model: posix InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin (at /usr/bin/clang) * C++ Compiler: Version Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1 Apple LLVM version 10.0.0 (clang-1000.11.45.5) Target: x86_64-apple-darwin17.7.0 Thread model: posix InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin (at /usr/bin/g++) Build performance summary: * Cores to use: 2 * Memory limit: 8192 MB
也有可能会遇到一些问题，这里我遇到的问题有：
- Xcode版本不符合，需要Xcode 4
- 无法找到gcc编译器
具体解决办法在本文最后提到。如果没有遇到问题就可以进一步编译了。
直接使用make all命令进行编译
make all
编译成功之后显示如下：
## Finished docs (build time 00:02:31) ----- Build times ------- Start 2019-06-21 16:43:05 End 2019-06-21 16:57:48 00:00:27 corba 00:00:55 demos 00:02:31 docs 00:03:43 hotspot 00:01:34 images 00:00:15 jaxp 00:00:24 jaxws 00:04:10 jdk 00:00:31 langtools 00:00:12 nashorn 00:14:43 TOTAL ------------------------- Finished building OpenJDK for target 'all'
在编译过程中还可能出现一些问题，目前我只遇到这一个问题：
- 参数错误“-std=gnu++98”，具体解决办法在本文最后提到。
四、运行
编译完成之后，在build文件夹中会生成一个名为macosx-x86_64-normal-server-release的文件夹，这里就是我们编译生成的结果。在这个文件夹中jdk就是OpenJDK编译成功的产物。
我们可以通过如下命令运行虚拟机，查看版本号，如果没什么问题终端会显示如下信息：
cd ./build/macosx-x86_64-normal-server-release/jdk/bin ./java -version openjdk version "1.8.0-internal" OpenJDK Runtime Environment (build 1.8.0-internal-zhengshuangxi_2019_06_21_17_25-b00) OpenJDK 64-Bit Server VM (build 25.71-b00, mixed mode)
运行之后我又遇到一个问题，在运行过程中会报错，提示 libjvm.dylib 动态链接库相关的错误。具体解决在本文最后。
五、遇到的问题及解决办法
5.1、运行configure之后，提示Xcode版本问题
checking for xcodebuild... /usr/bin/xcodebuild configure: error: Xcode 4 is required to build JDK 8, the version found was 10.1. Use --with-xcode-path to specify the location of Xcode 4 or make Xcode 4 active by using xcode-select. configure exiting with result code 1
我们只需要将文件 jdk8u-dev/common/autoconf/generated-configure.sh 进行一些修改，找到以下代码并进行注释，代码大约在26780行左右。注释之后就不会提示版本问题了
# Fail-fast: verify we're building on Xcode 4, we cannot build with Xcode 5 or later XCODE_VERSION=`$XCODEBUILD -version | grep '^Xcode ' | sed 's/Xcode //'` XC_VERSION_PARTS=( ${XCODE_VERSION//./ } ) if test ! "${XC_VERSION_PARTS[0]}" = "4"; then as_fn_error $? "Xcode 4 is required to build JDK 8, the version found was $XCODE_VERSION. Use --with-xcode-path to specify the location of Xcode 4 or make Xcode 4 active by using xcode-select." "$LINENO" 5 fi
5.2、gcc编译器找不到
configure: Will use user supplied compiler CC=clang checking for clang... /usr/bin/clang checking resolved symbolic links for CC... no symlink configure: The C compiler (located as /usr/bin/clang) does not seem to be the required gcc compiler. configure: The result from running with --version was: "" configure: error: A gcc compiler is required. Try setting --with-tools-dir. configure exiting with result code 1
解决办法也是在generated-configure.sh文件中注释掉以下的条件代码。注释的地方一共有两处：
# 第一处代码，27936行左右
elif test "x$TOOLCHAIN_TYPE" = xgcc; then # gcc --version output typically looks like # gcc (Ubuntu/Linaro 4.8.1-10ubuntu9) 4.8.1 # Copyright (C) 2013 Free Software Foundation, Inc. # This is free software; see the source for copying conditions. There is NO # warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. COMPILER_VERSION_OUTPUT=`$COMPILER --version 2>&1` # Check that this is likely to be GCC. $ECHO "$COMPILER_VERSION_OUTPUT" | $GREP "Free Software Foundation" > /dev/null # 条件语句注释掉 # if test $? -ne 0; then # { $as_echo "$as_me:${as_lineno-$LINENO}: The $COMPILER_NAME compiler (located as $COMPILER) does not seem to be the required $TOOLCHAIN_TYPE compiler." >&5 # $as_echo "$as_me: The $COMPILER_NAME compiler (located as $COMPILER) does not seem to be the required $TOOLCHAIN_TYPE compiler." >&6;} # { $as_echo "$as_me:${as_lineno-$LINENO}: The result from running with --version was: \"$COMPILER_VERSION\"" >&5 # $as_echo "$as_me: The result from running with --version was: \"$COMPILER_VERSION\"" >&6;} # as_fn_error $? "A $TOOLCHAIN_TYPE compiler is required. Try setting --with-tools-dir." "$LINENO" 5 # fi
# 第二处代码，29677行左右 elif test "x$TOOLCHAIN_TYPE" = xgcc; then # gcc --version output typically looks like # gcc (Ubuntu/Linaro 4.8.1-10ubuntu9) 4.8.1 # Copyright (C) 2013 Free Software Foundation, Inc. # This is free software; see the source for copying conditions. There is NO # warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. COMPILER_VERSION_OUTPUT=`$COMPILER --version 2>&1` # Check that this is likely to be GCC. $ECHO "$COMPILER_VERSION_OUTPUT" | $GREP "Free Software Foundation" > /dev/null # 条件语句注释掉 # if test $? -ne 0; then # { $as_echo "$as_me:${as_lineno-$LINENO}: The $COMPILER_NAME compiler (located as $COMPILER) does not seem to be the required $TOOLCHAIN_TYPE compiler." >&5 # $as_echo "$as_me: The $COMPILER_NAME compiler (located as $COMPILER) does not seem to be the required $TOOLCHAIN_TYPE compiler." >&6;} # { $as_echo "$as_me:${as_lineno-$LINENO}: The result from running with --version was: \"$COMPILER_VERSION\"" >&5 # $as_echo "$as_me: The result from running with --version was: \"$COMPILER_VERSION\"" >&6;} # as_fn_error $? "A $TOOLCHAIN_TYPE compiler is required. Try setting --with-tools-dir." "$LINENO" 5 # fi
注释完之后，重新运行configure
5.3、make过程中遇到参数错误“-std=gnu++98”
Making signal interposition lib... error: invalid argument '-std=gnu++98' not allowed with 'C' make[6]: *** [libjsig.dylib] Error 1 make[6]: *** Waiting for unfinished jobs.... make[5]: *** [the_vm] Error 2 make[4]: *** [product] Error 2 make[3]: *** [generic_build2] Error 2 make[2]: *** [product] Error 2 make[1]: *** [/Users/zhengshuangxi/mercurial/temp/build/macosx-x86_64-normal-server-release/hotspot/_hotspot.timestamp] Error 2 make: *** [hotspot-only] Error 2
在generated-configure.sh文件中找到参数“-std=gnu++98”，将代码注释如下：
LDFLAGS_JDK="$LDFLAGS_JDK -Wl,-z,relro" LEGACY_EXTRA_LDFLAGS="$LEGACY_EXTRA_LDFLAGS -Wl,-z,relro" fi 此处注释掉 #CXXSTD_CXXFLAG="-std=gnu++98"
之后重新运行configure，再执行make all
5.4、编译时遇到 lstdc++ 库无法找到
ld: library not found for -lstdc++ clang: error: linker command failed with exit code 1 (use -v to see invocation) make[6]: *** [libsaproc.dylib] Error 1 make[6]: *** Waiting for unfinished jobs.... make[5]: *** [the_vm] Error 2 make[4]: *** [product] Error 2 make[3]: *** [generic_build2] Error 2 make[2]: *** [product] Error 2 make[1]: *** [/Users/zhengshuangxi/mercurial/temp/build/macosx-x86_64-normal-server-release/hotspot/_hotspot.timestamp] Error 2 make: *** [hotspot-only] Error 2
这个原因是Xcode升级到10以后就没有包含lstdc++库了，解决办法是将/usr/lib中的库文件拷贝到Xcode相应的文件夹中，并设置相关的软连接。
sudo cp /usr/lib/libstdc++.6.0.9.dylib /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/lib/ cd /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/lib/ sudo ln -s libstdc++.6.0.9.dylib libstdc++.6.dylib sudo ln -s libstdc++.6.dylib libstdc++.dylib
然后重新运行make all命令进行编译。
5.5、编译完成之后，运行虚拟机时出现错误
# # A fatal error has been detected by the Java Runtime Environment: # # SIGILL (0x4) at pc=0x000000010fe801bf, pid=48116, tid=0x0000000000002203 # # JRE version: OpenJDK Runtime Environment (8.0) (build 1.8.0-internal-zhengshuangxi_2019_06_21_16_42-b00) # Java VM: OpenJDK 64-Bit Server VM (25.71-b00 mixed mode bsd-amd64 compressed oops) # Problematic frame: # V [libjvm.dylib+0x4801bf] PerfDataManager::destroy()+0xab # # Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again # # An error report file with more information is saved as: # /Users/zhengshuangxi/mercurial/temp/build/macosx-x86_64-normal-server-release/jdk/bin/hs_err_pid48116.log # # If you would like to submit a bug report, please visit: # http://bugreport.java.com/bugreport/crash.jsp # [error occurred during error reporting , id 0x4] Abort trap: 6
根据这个错误提示，我们可以知道错误发生在动态链接库 libjvm.dylib中，根据提示，错误代码时PerDataManager::destroy()函数中。因此我们需要对这个函数进行修改，即文件 hotspot/src/share/vm/runtime/perfData.cpp，在这个文件中将代码"delete p"注释掉。
问题的解决办法是在博客https://www.jianshu.com/p/34c8a8c37169中看到的。
// 大约在287行 void PerfDataManager::destroy() { if (_all == NULL) // destroy already called, or initialization never happened return; for (int index = 0; index < _all->length(); index++) { PerfData* p = _all->at(index); // 将delete p注释掉 //delete p; } delete(_all); delete(_sampled); delete(_constants); _all = NULL; _sampled = NULL; _constants = NULL; }
然后重新运行configure以及make all进行编译。之后就不会出现问题了。
