[flang-commits] [flang] [flang] Use precompiled headers in Lower, Parser and Semantics (PR #131137)

[Kajetan Puchalski via flang-commits]

mrkajetanp wrote:

> Lowering depends on Semantics and the Parser, and Semantics depends on Parser, have you tried using REUSE_FROM 

We shortly discussed this in a subthread under https://github.com/llvm/llvm-project/pull/130600.
In short, REUSE_FROM is an all-or-nothing kind of situation. With the feature it's not possible to reuse a different precompiled header unit and also add extra ones at the same time, you either re-use and existing one or have to build a new one completely from scratch.

Since the main goal is to reduce the memory usage per compilation thread, I didn't want to put too much into the precompiled headers either. If I tried adding the same Semantics headers on top of the Lower ones then the precompiled header for Lower/ would become probably the biggest TU in all of flang.



https://github.com/llvm/llvm-project/pull/131137