[NewPM] Separate out alias analysis passes in opt

[aeubanks]

Summary

This somewhat matches the --aa-pipeline option, which separates out any
AA analyses to make sure they run before other passes.

Makes check-llvm failures under new PM go from 2356 -> 2303.

AA passes are not handled by PassBuilder::parsePassPipeline() but rather
PassBuilder::parseAAPipeline(), which is why this fixes some failures.

[ychen]

LGTM with one nit.

llvm/include/llvm/Passes/PassBuilder.h

520

/// For compatibility with legacy pass manager. I would move this above the introduced loop in opt.cpp. Probably adding something like AA analyses are not specified separately when using legacy PM.

[aeubanks]

Address review

[asbirlea]

A general comment on the series of patches: it's great to have this means of testing the NPM through the legacy way of specifying passes, but I believe the long term goal is to only rely on specifying via passes=.... Most tests will need to be updated to get there, so having this mass testing available now is very useful!
Just note that when the transition is made to only use passes=... to opt, all additions made solely for matching the legacy -foo-pass arguments will need to be cleaned up (e.g. the API added here in PassBuilder.h)

llvm/tools/opt/NewPMDriver.cpp

331

Could you assert AAPipeline and AA passes inside Passes don't co-exist?

[aeubanks]

Add assert

[asbirlea]

Thank you!

llvm/include/llvm/Passes/PassBuilder.h

public:
   /// about the logic used. This routine just provides the textual mapping
   /// between AA names and the analyses to register with the manager.
   ///
   /// Returns false if the text cannot be parsed cleanly. The specific state of
   /// the \p AA manager is unspecified if such an error is encountered and this
   /// returns false.
   Error parseAAPipeline(AAManager &AA, StringRef PipelineText);
 
+  /// Returns true if the pass name is the name of an alias analysis pass.
+  bool isAAPassName(StringRef PassName);
+
   /// Register a callback for a default optimizer pipeline extension
   /// point
   ///
   /// This extension point allows adding passes that perform peephole
   /// optimizations similar to the instruction combiner. These passes will be
   /// inserted after each instance of the instruction combiner pass.
   void registerPeepholeEPCallback(
       const std::function<void(FunctionPassManager &, OptimizationLevel)> &C) {

llvm/lib/Passes/PassBuilder.cpp

while (!PipelineText.empty()) {
     if (!parseAAPassName(AA, Name))
       return make_error<StringError>(
           formatv("unknown alias analysis name '{0}'", Name).str(),
           inconvertibleErrorCode());
   }
 
   return Error::success();
 }
+
+bool PassBuilder::isAAPassName(StringRef PassName) {
+#define FUNCTION_ALIAS_ANALYSIS(NAME, CREATE_PASS)                             \
+  if (PassName == NAME)                                                        \
+    return true;
+#include "PassRegistry.def"
+  return false;
+}

llvm/tools/opt/NewPMDriver.cpp

 //===- NewPMDriver.cpp - Driver for opt with new PM -----------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 /// \file
 ///
 /// This file is just a split of the code that logically belongs in opt.cpp but
 /// that includes the new pass manager headers.
 ///
 //===----------------------------------------------------------------------===//
 
 #include "NewPMDriver.h"
 #include "PassPrinters.h"
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/CGSCCPassManager.h"
 #include "llvm/Bitcode/BitcodeWriterPass.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/LLVMContext.h"

 
 #define HANDLE_EXTENSION(Ext)                                                  \
   get##Ext##PluginInfo().RegisterPassBuilderCallbacks(PB);
 #include "llvm/Support/Extension.def"
 
   // Specially handle the alias analysis manager so that we can register
   // a custom pipeline of AA passes with it.
   AAManager AA;
+  if (!AAPipeline.empty()) {
+    assert(Passes.empty() &&
+           "--aa-pipeline and -foo-pass should not both be specified");
     if (auto Err = PB.parseAAPipeline(AA, AAPipeline)) {
       errs() << Arg0 << ": " << toString(std::move(Err)) << "\n";
       return false;
     }
+  }
+  // For compatibility with legacy pass manager.
+  // Alias analyses are not specially specified when using the legacy PM.
+  SmallVector<StringRef, 4> NonAAPasses;
+  for (auto PassName : Passes) {
+    if (PB.isAAPassName(PassName)) {
+      if (auto Err = PB.parseAAPipeline(AA, PassName)) {
+        errs() << Arg0 << ": " << toString(std::move(Err)) << "\n";
+        return false;
+      }
+    } else {
+      NonAAPasses.push_back(PassName);
+    }
+  }
 
   LoopAnalysisManager LAM(DebugPM);
   FunctionAnalysisManager FAM(DebugPM);
   CGSCCAnalysisManager CGAM(DebugPM);
   ModuleAnalysisManager MAM(DebugPM);
 
   // Register the AA manager first so that our version is the one used.
   FAM.registerPass([&] { return std::move(AA); });
 
if (!PassPipeline.empty()) {
     assert(Passes.empty() &&
            "PassPipeline and Passes should not both contain passes");
     if (auto Err =
             PB.parsePassPipeline(MPM, PassPipeline, VerifyEachPass, DebugPM)) {
       errs() << Arg0 << ": " << toString(std::move(Err)) << "\n";
       return false;
     }
   }
-  for (auto PassName : Passes) {
+  for (auto PassName : NonAAPasses) {
     if (auto Err =
             PB.parsePassPipeline(MPM, PassName, VerifyEachPass, DebugPM)) {
       errs() << Arg0 << ": " << toString(std::move(Err)) << "\n";
       return false;
     }
   }
 
   if (VK > VK_NoVerifier)