[clang] [clang] Factor out OpenACC part of `Sema` (PR #84184)

[Sam McCall via cfe-commits]

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@@ -1162,6 +1162,11 @@ class Sema final {
   /// CurContext - This is the current declaration context of parsing.
   DeclContext *CurContext;
 
+  SemaOpenACC &OpenACC() {
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sam-mccall wrote:

nit: per style guide, this should be `openACC()` (lowercase O), and it should be `getOpenAcc()` (verb phrase).

Personally, I think the verb-phrase rule when applied to getters is harmful enough to be worth ignoring (preferring [name according to side-effects](https://www.swift.org/documentation/api-design-guidelines/#name-according-to-side-effects)). So I'd be happiest with `openACC()`, but also fine with `getOpenACC()`.

(Picking this nit because I suspect we're going to have a bunch of these, and they should be consistent.)

https://github.com/llvm/llvm-project/pull/84184