[NewPM] Add TargetMachine method to add alias analyses

[aeubanks]

Summary

AMDGPUTargetMachine::adjustPassManager() adds some alias analyses to the
legacy PM. We need a way to do the same for the new PM in order to port
AMDGPUTargetMachine::adjustPassManager() to the new PM.

Currently the new PM adds alias analyses by creating an AAManager via
PassBuilder and overriding the AAManager a PassManager uses via
FunctionAnalysisManager::registerPass().

We will continue to respect a custom AA pipeline that specifies an exact
AA pipeline to use, but for "default" we will now add alias analyses
that backends specify. Most uses of PassManager use the "default"
AAManager created by PassBuilder::buildDefaultAAPipeline(). Backends can
override the newly added TargetMachine::registerAliasAnalyses() to add custom
alias analyses.

[ychen]

LGTM. The next step is to use this in AMDGPU and add tests?

[aeubanks]

In D93261#2466305, @ychen wrote:

LGTM. The next step is to use this in AMDGPU and add tests?

Yup. Likely it'll just be porting the existing passes and making sure existing AMDGPU tests also pass under the NPM (assuming there are ones that test that custom AA passes run under something like -O2).

llvm/include/llvm/Passes/PassBuilder.h

public:
   /// Build an O0 pipeline with the minimal semantically required passes.
   ///
   /// This should only be used for non-LTO and LTO pre-link pipelines.
   ModulePassManager buildO0DefaultPipeline(OptimizationLevel Level,
                                            bool LTOPreLink = false);
 
   /// Build the default `AAManager` with the default alias analysis pipeline
   /// registered.
+  ///
+  /// This also adds target-specific alias analyses registered via
+  /// TargetMachine::registerAliasAnalyses().
   AAManager buildDefaultAAPipeline();
 
   /// Parse a textual pass pipeline description into a \c
   /// ModulePassManager.
   ///
   /// The format of the textual pass pipeline description looks something like:
   ///
   ///   module(function(instcombine,sroa),dce,cgscc(inliner,function(...)),...)

llvm/include/llvm/Target/TargetMachine.h

 #include "llvm/IR/DataLayout.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Target/TargetOptions.h"
 #include <string>
 
 namespace llvm {
 
+class AAManager;
 class Function;
 class GlobalValue;
 class MachineModuleInfoWrapperPass;
 class Mangler;
 class MCAsmInfo;
 class MCContext;
 class MCInstrInfo;
 class MCRegisterInfo;
public:
   /// PassManagerBuilder::addExtension.
   virtual void adjustPassManager(PassManagerBuilder &) {}
 
   /// Allow the target to modify the pass pipeline with New Pass Manager
   /// (similar to adjustPassManager for Legacy Pass manager).
   virtual void registerPassBuilderCallbacks(PassBuilder &,
                                             bool DebugPassManager) {}
 
+  /// Allow the target to register alias analyses with the AAManager for use
+  /// with the new pass manager. Only affects the "default" AAManager.
+  virtual void registerAliasAnalyses(AAManager &) {}
+
   /// Add passes to the specified pass manager to get the specified file
   /// emitted.  Typically this will involve several steps of code generation.
   /// This method should return true if emission of this file type is not
   /// supported, or false on success.
   /// \p MMIWP is an optional parameter that, if set to non-nullptr,
   /// will be used to set the MachineModuloInfo for this PM.
   virtual bool
   addPassesToEmitFile(PassManagerBase &, raw_pwrite_stream &,

llvm/lib/Passes/PassBuilder.cpp

AAManager PassBuilder::buildDefaultAAPipeline() {
   AA.registerFunctionAnalysis<TypeBasedAA>();
 
   // Add support for querying global aliasing information when available.
   // Because the `AAManager` is a function analysis and `GlobalsAA` is a module
   // analysis, all that the `AAManager` can do is query for any *cached*
   // results from `GlobalsAA` through a readonly proxy.
   AA.registerModuleAnalysis<GlobalsAA>();
 
+  // Add target-specific alias analyses.
+  if (TM)
+    TM->registerAliasAnalyses(AA);
+
   return AA;
 }
 
 static Optional<int> parseRepeatPassName(StringRef Name) {
   if (!Name.consume_front("repeat<") || !Name.consume_back(">"))
     return None;
   int Count;
   if (Name.getAsInteger(0, Count) || Count <= 0)