Precompiled Header and Modules Internals¶ This document describes the design and implementation of Clang’s precompiled headers (PCH) and modules. If you are interested in the end-user view, please see the User’s Manual. Using Precompiled Headers with clang¶ The Clang compiler frontend, clang -cc1, supports two command line options for generating and using PCH files. To generate PCH files using cla