Revert "[NewPM] Remove CFGPrinterLegacyPass (llvm#73414)"

This reverts commit 9ba74c2.

Continue to support CFGPrinterLegacyPass for LGC, until it has
been converted to new pass manager.

Change-Id: I147a44afa8a011bbed28490de1f4dfb564c2fb58

Author: perlfu

llvm/include/llvm/Analysis/CFGPrinter.h

@@ -342,4 +342,9 @@ struct DOTGraphTraits<DOTFuncInfo *> : public DefaultDOTGraphTraits {
 };
 } // End llvm namespace
 
+namespace llvm {
+class FunctionPass;
+FunctionPass *createCFGPrinterLegacyPassPass();
+} // End llvm namespace
+
 #endif

llvm/include/llvm/InitializePasses.h

@@ -65,6 +65,7 @@ void initializeBranchRelaxationPass(PassRegistry&);
 void initializeBreakCriticalEdgesPass(PassRegistry&);
 void initializeBreakFalseDepsPass(PassRegistry&);
 void initializeCanonicalizeFreezeInLoopsPass(PassRegistry &);
+void initializeCFGPrinterLegacyPassPass(PassRegistry&);
 void initializeCFGSimplifyPassPass(PassRegistry&);
 void initializeCFGuardPass(PassRegistry&);
 void initializeCFGuardLongjmpPass(PassRegistry&);

llvm/lib/Analysis/Analysis.cpp

@@ -24,6 +24,7 @@ void llvm::initializeAnalysis(PassRegistry &Registry) {
   initializeCallGraphWrapperPassPass(Registry);
   initializeCallGraphDOTPrinterPass(Registry);
   initializeCallGraphViewerPass(Registry);
+  initializeCFGPrinterLegacyPassPass(Registry);
   initializeCycleInfoWrapperPassPass(Registry);
   initializeDependenceAnalysisWrapperPassPass(Registry);
   initializeDominanceFrontierWrapperPassPass(Registry);

llvm/lib/Analysis/CFGPrinter.cpp

@@ -19,6 +19,8 @@
 
 #include "llvm/Analysis/CFGPrinter.h"
 #include "llvm/ADT/PostOrderIterator.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/GraphWriter.h"
@@ -109,6 +111,37 @@ PreservedAnalyses CFGOnlyViewerPass::run(Function &F,
   return PreservedAnalyses::all();
 }
 
+namespace {
+struct CFGPrinterLegacyPass : public FunctionPass {
+  static char ID; // Pass identification, replacement for typeid
+  CFGPrinterLegacyPass() : FunctionPass(ID) {
+    initializeCFGPrinterLegacyPassPass(*PassRegistry::getPassRegistry());
+  }
+
+  bool runOnFunction(Function &F) override {
+    if (!CFGFuncName.empty() && !F.getName().contains(CFGFuncName))
+      return false;
+    auto *BPI = &getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
+    auto *BFI = &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI();
+    writeCFGToDotFile(F, BFI, BPI, getMaxFreq(F, BFI));
+    return false;
+  }
+
+  void print(raw_ostream &OS, const Module * = nullptr) const override {}
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    FunctionPass::getAnalysisUsage(AU);
+    AU.addRequired<BlockFrequencyInfoWrapperPass>();
+    AU.addRequired<BranchProbabilityInfoWrapperPass>();
+    AU.setPreservesAll();
+  }
+};
+} // namespace
+
+char CFGPrinterLegacyPass::ID = 0;
+INITIALIZE_PASS(CFGPrinterLegacyPass, "dot-cfg",
+                "Print CFG of function to 'dot' file", false, true)
+
 PreservedAnalyses CFGPrinterPass::run(Function &F,
                                       FunctionAnalysisManager &AM) {
   if (!CFGFuncName.empty() && !F.getName().contains(CFGFuncName))
@@ -156,6 +189,10 @@ void Function::viewCFGOnly(const BlockFrequencyInfo *BFI,
   viewCFG(true, BFI, BPI);
 }
 
+FunctionPass *llvm::createCFGPrinterLegacyPassPass() {
+  return new CFGPrinterLegacyPass();
+}
+
 /// Find all blocks on the paths which terminate with a deoptimize or 
 /// unreachable (i.e. all blocks which are post-dominated by a deoptimize 
 /// or unreachable). These paths are hidden if the corresponding cl::opts