[llvm] [Github] Add OpenMP docs to Github docs action (PR #70529)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 created https://github.com/llvm/llvm-project/pull/70529

This patch enables building the openmp documentation through Github actions during PRs and at tip of tree to ensure that the documentation builds and that there aren't any Sphinx warnings in a manner that enables more rapid developer iteration without having to install documentation tooling.

>From ba30647dee268af1ed0b94572b0482084b55f205 Mon Sep 17 00:00:00 2001
From: Aiden Grossman <agrossman154 at yahoo.com>
Date: Fri, 27 Oct 2023 16:03:55 -0700
Subject: [PATCH] [Github] Add OpenMP docs to Github docs action

This patch enables building the openmp documentation through Github
actions during PRs and at tip of tree to ensure that the documentation
builds and that there aren't any Sphinx warnings in a manner that
enables more rapid developer iteration without having to install
documentation tooling.
---
 .github/workflows/docs.yml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index e6af2f41167e0a1..b311a23f21af72e 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -21,6 +21,7 @@ on:
       - 'libcxx/docs/**'
       - 'libc/docs/**'
       - 'lld/docs/**'
+      - 'openmp/docs/**'
   pull_request:
     paths:
       - 'llvm/docs/**'
@@ -31,6 +32,7 @@ on:
       - 'libcxx/docs/**'
       - 'libc/docs/**'
       - 'lld/docs/**'
+      - 'openmp/docs/**'
 
 jobs:
   check-docs-build:
@@ -67,6 +69,8 @@ jobs:
               - 'libc/docs/**'
             lld:
               - 'lld/docs/**'
+            openmp:
+              - 'openmp/docs/**'
       - name: Fetch LLVM sources (PR)
         if: ${{ github.event_name == 'pull_request' }}
         uses: actions/checkout at v4
@@ -125,4 +129,9 @@ jobs:
         run: |
           cmake -B lld-build -GNinja -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS="lld" -DLLVM_ENABLE_SPHINX=ON ./llvm
           TZ=UTC ninja -C lld-build docs-lld-html
+      - name: Build OpenMP docs
+        if: steps.docs-changed-subprojects.outputs.openmp_any_changed == 'true'
+        run: |
+          cmake -B openmp-build -GNinja -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS="clang;openmp" -DLLVM_ENABLE_SPHINX=ON ./llvm
+          TZ=UTC ninja -C openmp-build docs-openmp-html