[llvm][release] Add links to automatically built packages on release page

This adds links to the release packages that are automatically built
using GitHub, so that users of those platforms can find them more
easily.

The approach taken:
* "LLVM x.y.z Release" becomes the title for this links section.
* No hand built files are linked to because we can't be sure
  when or if they will appear. It's better that users check the
  full file list if they need those.
* This means no Windows links, but I've specifically mentioned
  Windows just below the links to mitigate this.
* I have tried to use the vendor names for the architectures,
  that casual users would recognise.
* Their signature file is linked as well. I expect most will ignore
  this but better to show it to remind people it exists.
* I called it "signature" as a generic term to cover the .jsonl
  and .sig files, but we're not linking to any .sig files yet.
* Links are initially commented out and there is a placeholder string.
  Once all binaries are built, the placeholder is removed and the
  download links revelealed (we wait for them all so we don't
  have many jobs racing to update the release text).

I considered generating this using a lot of templates, but
considering the small number of links and how useful it is to
see the layout in the Python file, I prefer writing it out.

Author: DavidSpickett

.github/workflows/release-tasks.yml

@@ -111,3 +111,31 @@ jobs:
     # Called workflows don't have access to secrets by default, so we need to explicitly pass secrets that we use.
     secrets:
       RELEASE_TASKS_USER_TOKEN: ${{ secrets.RELEASE_TASKS_USER_TOKEN }}
+
+  uncomment-download-links:
+    name: Uncomment download links
+    runs-on: ubuntu-24.04
+    permissions:
+      contents: write # For updating the release message.
+    needs:
+      - validate-tag
+      - release-create
+      - release-binaries
+
+    steps:
+      - name: Install Dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install python3-github
+
+      - name: Checkout LLVM
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+        with:
+          sparse-checkout: llvm/utils/release/github-upload-release.py
+          sparse-checkout-cone-mode: false
+
+      - name: Uncomment Download Links
+        env:
+          GITHUB_TOKEN: ${{ github.token }}
+        run: |
+          ./llvm/utils/release/./github-upload-release.py --token "$GITHUB_TOKEN" --release ${{ needs.validate-tag.outputs.release-version }} uncomment_download_links

llvm/utils/release/github-upload-release.py

@@ -45,9 +45,26 @@ def create_release(repo, release, tag=None, name=None, message=None):
         # Note that these lines are not length limited because if we do so, GitHub
         # assumes that should be how it is laid out on the page. We want GitHub to
         # do the reflowing for us instead.
+        #
+        # Once all the atuomatic binary builds have completed, the HTML comments
+        # in the text below will be removed to reveal the download links.
         message = dedent(
             """\
-LLVM {release} Release
+## LLVM {release} Release
+
+<!-- DOWNLOAD_LINKS_BEGIN
+**Linux:**
+* [x86_64](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-Linux-X64.tar.xz) ([signature](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-Linux-X64.tar.xz.jsonl))
+* [Arm64](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-Linux-ARM64.tar.xz) ([signature](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-Linux-ARM64.tar.xz.jsonl))
+
+**macOS:**
+* [Apple Silicon](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-macOS-ARM64.tar.xz) (ARM64) ([signature](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-macOS-ARM64.tar.xz.jsonl))
+* [Intel](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-macOS-X64.tar.xz) (x86-64) ([signature](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-macOS-X64.tar.xz.jsonl))
+DOWNLOAD_LINKS_END -->
+
+Download links for Linux and macOS will appear here when all the builds have completed. <!-- DOWNLOAD_LINKS_PLACEHOLDER -->
+
+For Windows, and any other variants of platform and architecture, check the full list of release packages at the bottom of this release page.
 
 ## Package Types
 
@@ -95,9 +112,35 @@ def upload_files(repo, release, files):
         print("Done")
 
 
+def uncomment_download_links(repo, release):
+    release = repo.get_release("llvmorg-{}".format(release))
+
+    new_message = []
+    to_remove = [
+        "DOWNLOAD_LINKS_BEGIN",
+        "DOWNLOAD_LINKS_END",
+        "DOWNLOAD_LINKS_PLACEHOLDER",
+    ]
+    for line in release.body.splitlines():
+        for comment in to_remove:
+            if comment in line:
+                break
+        else:
+            new_message.append(line)
+
+    release.update_release(
+        name=release.title,
+        message="\n".join(new_message),
+        draft=release.draft,
+        prerelease=release.prerelease,
+    )
+
+
 parser = argparse.ArgumentParser()
 parser.add_argument(
-    "command", type=str, choices=["create", "upload", "check-permissions"]
+    "command",
+    type=str,
+    choices=["create", "upload", "check-permissions", "uncomment_download_links"],
 )
 
 # All args
@@ -137,3 +180,5 @@ def upload_files(repo, release, files):
     create_release(llvm_repo, args.release)
 if args.command == "upload":
     upload_files(llvm_repo, args.release, args.files)
+if args.command == "uncomment_download_links":
+    uncomment_download_links(llvm_repo, args.release)