The goal is to reduce the startup time cost of
all of these parsing and string replacement.
All comments are now stripped at compile time.
This comment check added noticeable slowdown at
startup in debug builds and during preprocessing.
Put all metadatas between start and end token.
Use very simple parsing using `StringRef` and
hash all identifiers.
Move all the complexity to the preprocessor that
massagess the metadata into a well expected input
to the runtime parser.
All identifiers are compile time hashed so that no string
comparison is made at runtime.
Speed up the source loading:
- from 10ms to 1.6ms (6.25x speedup) in release
- from 194ms to 6ms (32.3x speedup) in debug
Follow up #129009
Pull Request: https://projects.blender.org/blender/blender/pulls/128927