[llvm] [ctx_prof] Automatically convert available external linkage to local for modules with contextual roots (PR #109203)

[Teresa Johnson via llvm-commits]

================
@@ -125,8 +126,10 @@ static bool eliminateAvailableExternally(Module &M) {
 }
 
 PreservedAnalyses
-EliminateAvailableExternallyPass::run(Module &M, ModuleAnalysisManager &) {
-  if (!eliminateAvailableExternally(M))
-    return PreservedAnalyses::all();
+EliminateAvailableExternallyPass::run(Module &M, ModuleAnalysisManager &MAM) {
+  auto *CtxProf = MAM.getCachedResult<CtxProfAnalysis>(M);
+  if (!eliminateAvailableExternally(M, (CtxProf && !!(*CtxProf))))
----------------
teresajohnson wrote:

add a comment about why

https://github.com/llvm/llvm-project/pull/109203