如何查看JAVA程序的汇编代码
如何查看JAVA程序的汇编代码
查看汇编需要加入虚拟机参数
-XX:+UnlockDiagnosticVMOptions -XX:+PrintAssmbly
运行后可能会出现
Could not load hsdis-amd64.so; library not loadable; PrintAssembly is disabled
很明显是缺失hsdis-amd64.so这个库（linux下）
解决方案：
需要的库源码下载地址：https://sourceforge.net/projects/fcml/files/fcml-1.1.3/
Linux下：
1. 下载源码并解压
2. 切换到目标目录
3. ./configure && make && sudo make install
4. cd example/hsdis && make && sudo make install
5. sudo ln -s /usr/local/lib/libhsdis.so
6. sudo ln -s /usr/local/lib/libhsdis.so
接下来便可以使用
Windos下：
1. 下载压缩包并提取dll文件
2. 搜索Windos下JDK目录和JRE目录找到含有java.dll的目录,我的是包含在
C:\Program Files\Java\jre1.8.0_45\bin\server
C:\Program Files\Java\jre1.8.0_45\jre\bin\server
3. 复制到搜索的目录中
最终效果：
编译的java代码
public class Test{
public static void main(String[] args){
System.out.println(1);
}
}显示的汇编代码：
Java HotSpot(TM) 64-Bit Server VM warning: PrintAssembly is enabled; turning on DebugNonSafepoints to gain additional output
Loaded disassembler from /var/software/java/jdk1.8.0_151/jre/lib/amd64/hsdis-amd64.so
Decoding compiled method 0x00007f56f9102150:
Code:
Argument 0 is unknown.RIP: 0x7f56f91022a0 Code size: 0x00000110
[Disassembling for mach='amd64']
[Entry Point]
[Constants]
# {method} {0x00007f56f3211c38} 'getSnapshotTransformerList' '()[Lsun/instrument/TransformerManager$TransformerInfo;' in 'sun/instrument/TransformerManager'
# [sp+0x40] (sp of caller)
0x00007f56f91022a0: mov 0x8(%rsi),%r10d
0x00007f56f91022a4: shl $0x3,%r10
0x00007f56f91022a8: cmp %rax,%r10
0x00007f56f91022ab: jne 0x7f56f9045e20 ; {runtime_call}
0x00007f56f91022b1: nopw 0x0(%rax,%rax)
0x00007f56f91022bc: nop
[Verified Entry Point]
0x00007f56f91022c0: mov %eax,0xfffffffffffec000(%rsp)
0x00007f56f91022c7: push %rbp
0x00007f56f91022c8: sub $0x30,%rsp ;*aload_0
; - sun.instrument.TransformerManager::getSnapshotTransformerList@0 (line 166)
0x00007f56f91022cc: mov 0x10(%rsi),%eax
0x00007f56f91022cf: shl $0x3,%rax ;*getfield mTransformerList
; - sun.instrument.TransformerManager::getSnapshotTransformerList@1 (line 166)
0x00007f56f91022d3: add $0x30,%rsp
0x00007f56f91022d7: pop %rbp
0x00007f56f91022d8: test %eax,0x16e0ee22(%rip) ; {poll_return}
0x00007f56f91022de: retq
0x00007f56f91022df: nop
0x00007f56f91022e0: nop
0x00007f56f91022e1: mov 0x2a8(%r15),%rax
0x00007f56f91022e8: movabs $0x0,%r10
0x00007f56f91022f2: mov %r10,0x2a8(%r15)
0x00007f56f91022f9: movabs $0x0,%r10
0x00007f56f9102303: mov %r10,0x2b0(%r15)
0x00007f56f910230a: add $0x30,%rsp
0x00007f56f910230e: pop %rbp
0x00007f56f910230f: jmpq 0x7f56f906e2e0 ; {runtime_call}
0x00007f56f9102314: hlt
0x00007f56f9102315: hlt
0x00007f56f9102316: hlt
0x00007f56f9102317: hlt
0x00007f56f9102318: hlt
0x00007f56f9102319: hlt
0x00007f56f910231a: hlt
0x00007f56f910231b: hlt
0x00007f56f910231c: hlt
0x00007f56f910231d: hlt
0x00007f56f910231e: hlt
0x00007f56f910231f: hlt
[Exception Handler]
[Stub Code]
0x00007f56f9102320: callq 0x7f56f90fd660 ; {no_reloc}
0x00007f56f9102325: mov %rsp,0xffffffffffffffd8(%rsp)
0x00007f56f910232a: sub $0x80,%rsp
0x00007f56f9102331: mov %rax,0x78(%rsp)
0x00007f56f9102336: mov %rcx,0x70(%rsp)
0x00007f56f910233b: mov %rdx,0x68(%rsp)
0x00007f56f9102340: mov %rbx,0x60(%rsp)
0x00007f56f9102345: mov %rbp,0x50(%rsp)
0x00007f56f910234a: mov %rsi,0x48(%rsp)
0x00007f56f910234f: mov %rdi,0x40(%rsp)
0x00007f56f9102354: mov %r8,0x38(%rsp)
0x00007f56f9102359: mov %r9,0x30(%rsp)
0x00007f56f910235e: mov %r10,0x28(%rsp)
0x00007f56f9102363: mov %r11,0x20(%rsp)
0x00007f56f9102368: mov %r12,0x18(%rsp)
0x00007f56f910236d: mov %r13,0x10(%rsp)
0x00007f56f9102372: mov %r14,0x8(%rsp)
0x00007f56f9102377: mov %r15,(%rsp)
0x00007f56f910237b: movabs $0x7f570ee0a316,%rdi ; {external_word}
0x00007f56f9102385: movabs $0x7f56f9102325,%rsi ; {internal_word}
0x00007f56f910238f: mov %rsp,%rdx
0x00007f56f9102392: and $0xfffffffffffffff0,%rsp
0x00007f56f9102396: callq 0x7f570eb35d80 ; {runtime_call}
0x00007f56f910239b: hlt内容翻译转载，原答案出自：
https://stackoverflow.com/questions/1503479/how-to-see-jit-compiled-code-in-jvm/24524285#24524285?newreg=de4f506929a54c10b77d7e9e1d1bb94e
内容过多只显示部分
趁着时光还没有关注你的时候多看看，多学一点