>[TOC]

# 编译JVM遇见的问题

环境：ubuntu20.04TSL

## 1、安装gcc

```shell
sudo apt-get install build-essential
```

## 2、接着安装以下依赖库：

| 命令                                                         | 工具       |
| ------------------------------------------------------------ | ---------- |
| sudo apt-get install libfreetype6-dev                        | FreeType   |
| sudo apt-get install libcups2-dev                            | CUPS       |
| sudo apt-get install libx11-dev libxext-dev libxrender-dev libxrandr-dev libxtst-dev libxt-dev | X11        |
| sudo apt-get install libasound2-dev                          | ALSA       |
| sudo apt-get install libffi-dev                              | libffi     |
| sudo apt-get install autoconf                                | Autoconf   |
| sudo apt-get install libfontconfig1-dev                      | fontconfig |

## 3、安装JDK11

由于openjdk很多部分由java实现的，假设需要编译的版本为N，需要装一个版本号大于等于N-1的jdk，我们需要编译openjdk12，所以需要装JDK11及之后的版本，命令如下：

```shell
sudo apt-get install openjdk-11-jdk
```

## 4、编译

```shell
# 1.检查编译环境
bash configure --enable-debug --with-jvm-variants=server
# 2.显示如下代码

A new configuration has been successfully created in
/home/xiang/win_d/java/jdk12-06222165c35f/build/linux-x86_64-server-fastdebug
using configure arguments '--enable-debug --with-jvm-variants=server'.

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 zgc' 
* OpenJDK target: OS: linux, CPU architecture: x86, address length: 64
* Version string: 12-internal+0-adhoc.xiang.jdk12-06222165c35f (12-internal)

Tools summary:
* Boot JDK:       openjdk version "11.0.7" 2020-04-14 OpenJDK Runtime Environment (build 11.0.7+10-post-Ubuntu-3ubuntu1) OpenJDK 64-Bit Server VM (build 11.0.7+10-post-Ubuntu-3ubuntu1, mixed mode, sharing)  (at /usr/lib/jvm/java-11-openjdk-amd64)
* Toolchain:      gcc (GNU Compiler Collection)
* C Compiler:     Version 9.3.0 (at /usr/bin/gcc)
* C++ Compiler:   Version 9.3.0 (at /usr/bin/g++)

Build performance summary:
* Cores to use:   4
* Memory limit:   7858 MB

# 3.接着执行
make images

# 4.报错
ERROR: Build failed for target 'images' in configuration 'linux-x86_64-server-fastdebug' (exit code 2) 
Stopping sjavac server

=== Output from failing command(s) repeated here ===
* For target hotspot_variant-server_libjvm_objs_arguments.o:
In file included from /usr/include/string.h:495,
                 from /home/xiang/win_d/java/jdk12-06222165c35f/src/hotspot/share/utilities/globalDefinitions_gcc.hpp:35,
                 from /home/xiang/win_d/java/jdk12-06222165c35f/src/hotspot/share/utilities/globalDefinitions.hpp:32,
                 from /home/xiang/win_d/java/jdk12-06222165c35f/src/hotspot/share/utilities/align.hpp:28,
                 from /home/xiang/win_d/java/jdk12-06222165c35f/src/hotspot/share/runtime/globals.hpp:29,
                 from /home/xiang/win_d/java/jdk12-06222165c35f/src/hotspot/share/memory/allocation.hpp:28,
                 from /home/xiang/win_d/java/jdk12-06222165c35f/src/hotspot/share/classfile/classLoaderData.hpp:28,
                 from /home/xiang/win_d/java/jdk12-06222165c35f/src/hotspot/share/precompiled/precompiled.hpp:34:
In function ‘char* strncpy(char*, const char*, size_t)’,
    inlined from ‘static jint Arguments::parse_each_vm_init_arg(const JavaVMInitArgs*, bool*, JVMFlag::Flags)’ at /home/xiang/win_d/java/jdk12-06222165c35f/src/hotspot/share/runtime/arguments.cpp:2472:29:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:34: error: ‘char* __builtin_strncpy(char*, const char*, long unsigned int)’ output truncated before terminating nul copying as many bytes from a string as its length [-Werror=stringop-truncation]
  106 |   return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
   ... (rest of output omitted)

* All command lines available in /home/xiang/win_d/java/jdk12-06222165c35f/build/linux-x86_64-server-fastdebug/make-support/failure-logs.
=== End of repeated output ===

No indication of failed target found.
Hint: Try searching the build log for '] Error'.
Hint: See doc/building.html#troubleshooting for assistance.

```

## 5、解决问题

1. gcc和g++版本过高，需要更换版本

```shell
# 1.安装gcc7
sudo apt-get install gcc-7 gcc-7-multilib g++-7 g++-7-multilib

# 2.查看gcc和g++分别有那些软件:
ll /usr/bin/gcc*
ll /usr/bin/g++*

# 3.最后将/usr/bin下面以下文件通过软连接重新指向版本7
/usr/bin/gcc
/usr/bin/gcc-ar
/usr/bin/gcc-nm
/usr/bin/gcc-ranlib
/usr/bin/g++ 
```

2. 执行shell脚本

```shell

COMMAND=(/usr/bin/gcc /usr/bin/gcc-ar /usr/bin/gcc-nm /usr/bin/gcc-ranlib /usr/bin/g++)

for command in "${COMMAND[@]}"
do
  rm $command
  ln -s "$command"-7 $command
done

```

3. 重新编译

```shell
make clean
make dist-clean

bash configure --enable-debug --with-jvm-variants=server
make images
```

输出一下内容编译成功

![image-20211201101145958](assets/image-20211201101145958.png)