ldc Preliminary support for LLVM 20 RTSan

This pull request adds basic RTSan (real-time sanitizer) support for D developers to check if their applications are real-time safe (i.e. suitable to use in a real-time context).

Needs #4911. Fix #4755.

May 09 '25 09:05 liushuyu

One of the authors of rtsan here, was just linked this PR!

Just shout if you have any questions. Excited to see it go into D

May 09 '25 21:05 cjappl

An overall note before I look any further - it may be simpler to break this up into:

Updating to llvm20
Adding rtsan

Seems like there are two major steps being done in this single PR. Breaking them up would make it easier to review and roll back upon an issue

May 09 '25 21:05 cjappl

Hi, thank you for your review!

An overall note before I look any further - it may be simpler to break this up into:
1. Updating to llvm20

2. Adding rtsan
Seems like there are two major steps being done in this single PR. Breaking them up would make it easier to review and roll back upon an issue

This is also why this is a draft. I am currently waiting on LLVM upstream to fix a LLVM 20 regression that breaks LDC in a very bad way (see #4911). This pull request will be rebased when that LLVM 20 upgrade pull request lands.

May 10 '25 04:05 liushuyu