[PM] Make the AnalysisManager parameter to run methods a reference.

This was originally a pointer to support pass managers which didn't use
AnalysisManagers. However, that doesn't realistically come up much and
the complexity of supporting it doesn't really make sense.

In fact, *many* parts of the pass manager were just assuming the pointer
was never null already. This at least makes it much more explicit and
clear.

llvm-svn: 263219
diff --git a/llvm/lib/Analysis/PostDominators.cpp b/llvm/lib/Analysis/PostDominators.cpp
index b515108..8d3452e 100644
--- a/llvm/lib/Analysis/PostDominators.cpp
+++ b/llvm/lib/Analysis/PostDominators.cpp
@@ -56,9 +56,9 @@
   : OS(OS) {}
 
 PreservedAnalyses
-PostDominatorTreePrinterPass::run(Function &F, FunctionAnalysisManager *AM) {
+PostDominatorTreePrinterPass::run(Function &F, FunctionAnalysisManager &AM) {
   OS << "PostDominatorTree for function: " << F.getName() << "\n";
-  AM->getResult<PostDominatorTreeAnalysis>(F).print(OS);
+  AM.getResult<PostDominatorTreeAnalysis>(F).print(OS);
 
   return PreservedAnalyses::all();
 }