Interceptor

WARNING: The interceptor is still a work in progress. Contents of this section are subject to change.

The interceptor is a tool to intercept all execve and other system calls during the build (specifically, make) in order to construct the dependency tree and understand a list of commands executed by the build system. With the interceptor, the Bazel build system may first "dry-run", analyze all inputs and outputs of each command, generate BUILD.bazel files for each command, then execute on these generated build files.

This allows us to enable the following:

• Trim the dependency tree for each command.
  • Reduce the possibility of invalidating an output when an unrelated input file is touched
  • More parallelism within Bazel, not make
  • Even faster incremental builds
• Generate compile_commands.json, which can then be plugged into IDEs and code search tools (e.g. https://cs.android.com/android/kernel/superproject)
• More cache hits for Remote Build Execution (RBE)
• Give a more trimmed and precise list of resources for DDK
• etc.