openjdk源码了解

openjdk给出debug配置选项，common/autoconf/jdk-options.m4

AC_DEFUN_ONCE([JDKOPT_SETUP_DEBUG_LEVEL],
[
  ###############################################################################
  #
  # Set the debug level
  #    release: no debug information, all optimizations, no asserts.
  #    fastdebug: debug information (-g), all optimizations, all asserts
  #    slowdebug: debug information (-g), no optimizations, all asserts
  #
  DEBUG_LEVEL="release"
  AC_MSG_CHECKING([which debug level to use])
  AC_ARG_ENABLE([debug], [AS_HELP_STRING([--enable-debug],
      [set the debug level to fastdebug (shorthand for --with-debug-level=fastdebug) @<:@disabled@:>@])],
      [
        ENABLE_DEBUG="${enableval}"
        DEBUG_LEVEL="fastdebug"
      ], [ENABLE_DEBUG="no"])

  AC_ARG_WITH([debug-level], [AS_HELP_STRING([--with-debug-level],
      [set the debug level (release, fastdebug, slowdebug) @<:@release@:>@])],
      [
        DEBUG_LEVEL="${withval}"
        if test "x$ENABLE_DEBUG" = xyes; then
          AC_MSG_ERROR([You cannot use both --enable-debug and --with-debug-level at the same time.])
        fi
      ])
  AC_MSG_RESULT([$DEBUG_LEVEL])

  if test "x$DEBUG_LEVEL" != xrelease && \
      test "x$DEBUG_LEVEL" != xfastdebug && \
      test "x$DEBUG_LEVEL" != xslowdebug; then
    AC_MSG_ERROR([Allowed debug levels are: release, fastdebug and slowdebug])
  fi

开启调试信息

./configure --with-target-bits=64 --with-debug-level=slowdebug --enable-debug-symbols ZIP_DEBUGINFO_FILES=0

--with-boot-jdk：指定引导JDK所在目录；

--with-target-bits：指定编译64位系统的JDK；

为可以进行源码调试，再指定下面三个参数：

--with-debug-level=slowdebug：指定可以生成最多的调试信息；

--enable-debug-symbols ZIP_DEBUGINFO_FILES=0：生成调试的符号信息，并且不压缩

执行编译命令

make all ZIP_DEBUGINFO_FILES=0

java调试用例源码

https://github.com/fenixsoft/jvm_book.git

执行java的C++代码

关键执行class字节码步骤

1、加载MainClass

2、获取appClass

3、获取MainID和入参

4、执行java的main函数

执行的所有线程栈

堆空间OOM

疑问

libjvm.so 明明有编译信息，却没有符号

而且也断点不到oom需要打印的函数，估计不是搜到的退出函数了。