[all-commits] [llvm/llvm-project] 4afa9c: [libc++] Persistently cache memoized operations du...

[Louis Dionne via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 4afa9c17262cbca3f85352c8d3f352639f83e0b3
      https://github.com/llvm/llvm-project/commit/4afa9c17262cbca3f85352c8d3f352639f83e0b3
  Author: Louis Dionne <ldionne.2 at gmail.com>
  Date:   2022-01-18 (Tue, 18 Jan 2022)

  Changed paths:
    M libcxx/utils/libcxx/test/dsl.py

  Log Message:
  -----------
  [libc++] Persistently cache memoized operations during Lit configuration

When invoking Lit repeatedly, we perform all the configuration checks
over and over again, which takes a lot of time. This patch allows caching
the result of configuration checks persistently across Lit invocations to
speed this up.

In theory, this should still be functionally correct since the cache
key should contain everything that determines the output of the
configuration check. However, in cases where e.g. the compiler has
changed but is at the same path as previously, the Lit configuration
checks will be cached even though technically the cache should have
been invalidated.

Differential Revision: https://reviews.llvm.org/D117361