[IR] Lazily initialize the class to pass name mapping (NFC) (#96321)

Initializing this map is somewhat expensive (especially for O0), so we
currently only do it if certain flags are used. I would like to make use
of it for crash dumps (#96078), where we don't know in advance whether
it will be needed or not.

This patch changes the initialization to a lazy approach, where a
callback is registered that does the actual initialization. The
callbacks will be run the first time the pass name is requested.

This way there is no compile-time impact if the mapping is not used.

0 files changed, 0 insertions, 0 deletions