tree a3c538c1cf7b07d6463388214087a30c926af967
parent 547e197662b70fc9f2103f6b545df43a70c7cc05
author Cheng Chen <chengchen@google.com> 1585164558 -0700
committer Cheng Chen <chengchen@google.com> 1585260148 -0700

Refactor firstpass: break the main function to a few functions.

(1). Add two sub functions.
(2). Group a few parameters into a structure for readability.
(3). Add comments for these parameters.

Change-Id: If5e926480e759f6e2b30eb8f1057a991ddd80498