Android12 不支持 ccache 编译缓存问题

问题原因

源码使用的ccach版本太旧，经常产生各种问题，官方停用了ccach，需要使用建议用户安装新版本的ccache，配置使用

• 官方 build/core/ccache.mk 文件中的解释

  # We no longer provide a ccache prebuilt.
  #
  # Ours was old, and had a number of issues that triggered non-reproducible
  # results and other failures. Newer ccache versions may fix some of those
  # issues, but at the large scale of our build servers, we weren't seeing
  # significant performance gains from using ccache -- you end up needing very
  # good locality and/or very large caches if you're building many different
  # configurations.
  #
  # Local no-change full rebuilds were showing better results, but why not just
  # use incremental builds at that point?
  #
  # So if you still want to use ccache, continue setting USE_CCACHE, but also set
  # the CCACHE_EXEC environment variable to the path to your ccache executable.

  解决方案

• 1.安装ccache

  sudo apt-get install ccache

• 2.添加ccach环境变量以及配置 修改文件 ~/.bashrc

  export USE_CCACHE=1 #使用ccache
  export CCACHE_EXEC=/usr/bin/ccache #使用配置程序路径，不清楚可用 whereis ccache 查询
  export CCACHE_DIR=~/.ccache #缓存路径，建议放在固态硬盘
  export CCACHE_COMPRESS=1 #压缩,会损失部分性能
  ${CCACHE_EXEC} -M 100G #设置缓存空间大小

• 3.修改build下的文件 修改 build/core/ccache.mk 文件

  ......
  CCACHE_EXEC := /usr/bin/ccache #保证在下面句之前即可
  ifneq ($(CCACHE_EXEC),)
  ......

  更多关于ccache

  ccache是一个编译缓存工具，除了android源码编译可用通过ccache提高编译速度外，其他项目也能使用想了解更多用法可通过下面地址查看了解。 文档：ccache (简体中文)