JVM print assembly code

需要反汇编插件，不然看到的就是二进制代码了。hsdis HotSpot Disassembly Plugin Downloads

这篇文章值得参考一下CompileCommand JVM option | It’s All Relative

如果我想看trino package下面生成的汇编代码，可以在 `jvm.config` 里面配置

• 允许对jvm进行diagnose
• 对所有的package都不打印汇编代码，否则每个类/方法都会打印生成的汇编代码
• 然后针对 `io/trino/sql` 这个package下面所有的类/方法打印汇编代码

-XX:+UnlockDiagnosticVMOptions
-XX:-PrintAssembly
-XX:CompileCommand=option,io.trino.sql.*::*,PrintAssembly,+

最后输出的结果是在 `log/var/log/launcher.log` 里面

============================= C2-compiled nmethod ==============================
----------------------------------- Assembly -----------------------------------

Compiled method (c2) 29768 25579       4       io.trino.sql.gen.ExpressionProfiler::start (12 bytes)
 total in heap  [0x00007fc978886590,0x00007fc978886880] = 752
 relocation     [0x00007fc9788866e0,0x00007fc978886700] = 32
 main code      [0x00007fc978886700,0x00007fc9788867d0] = 208
 stub code      [0x00007fc9788867d0,0x00007fc9788867e8] = 24
 oops           [0x00007fc9788867e8,0x00007fc9788867f0] = 8
 metadata       [0x00007fc9788867f0,0x00007fc978886808] = 24
 scopes data    [0x00007fc978886808,0x00007fc978886828] = 32
 scopes pcs     [0x00007fc978886828,0x00007fc978886868] = 64
 dependencies   [0x00007fc978886868,0x00007fc978886870] = 8
 nul chk table  [0x00007fc978886870,0x00007fc978886880] = 16

如果加上下面两个选项, 可以在 `log/assembly.log` 里面得到比较详细的编译信息，这个日志可以喂给JITWatch来看。

-XX:+LogCompilation
-XX:LogFile=assembly.log