[ThinLTO] Port InlinerFunctionImportStats handling to new PM

[tejohnson]

Summary

The InlinerFunctionImportStats will collect and dump stats regarding how
many function inlined into the module were imported by ThinLTO.

[wmi]

LGTM.

include/llvm/Transforms/IPO/Inliner.h

 /// doing considerable DCE including the DCE of dead functions. This pass makes
 /// every attempt to be simpler. DCE of functions requires complex reasoning
 /// about comdat groups, etc. Instead, it is expected that other more focused
 /// passes be composed to achieve the same end result.
 class InlinerPass : public PassInfoMixin<InlinerPass> {
 public:
   InlinerPass(InlineParams Params = getInlineParams())
       : Params(std::move(Params)) {}
+  ~InlinerPass();
+  InlinerPass(InlinerPass &&Arg)
+      : Params(std::move(Arg.Params)),
+        ImportedFunctionsStats(std::move(Arg.ImportedFunctionsStats)) {}
 
   PreservedAnalyses run(LazyCallGraph::SCC &C, CGSCCAnalysisManager &AM,
                         LazyCallGraph &CG, CGSCCUpdateResult &UR);
 
 private:
   InlineParams Params;
+  std::unique_ptr<ImportedFunctionsInliningStatistics> ImportedFunctionsStats;
 };
 
 } // end namespace llvm
 
 #endif // LLVM_TRANSFORMS_IPO_INLINER_H

lib/Transforms/IPO/Inliner.cpp

FunctionsToRemove.erase(
       FunctionsToRemove.end());
   for (CallGraphNode *CGN : FunctionsToRemove) {
     delete CG.removeFunctionFromModule(CGN);
     ++NumDeleted;
   }
   return true;
 }
 
+InlinerPass::~InlinerPass() {
+  if (ImportedFunctionsStats) {
+    assert(InlinerFunctionImportStats != InlinerFunctionImportStatsOpts::No);
+    ImportedFunctionsStats->dump(InlinerFunctionImportStats ==
+                                 InlinerFunctionImportStatsOpts::Verbose);
+  }
+}
+
 PreservedAnalyses InlinerPass::run(LazyCallGraph::SCC &InitialC,
                                    CGSCCAnalysisManager &AM, LazyCallGraph &CG,
                                    CGSCCUpdateResult &UR) {
   const ModuleAnalysisManager &MAM =
       AM.getResult<ModuleAnalysisManagerCGSCCProxy>(InitialC, CG).getManager();
   bool Changed = false;
 
   assert(InitialC.size() > 0 && "Cannot handle an empty SCC!");
   Module &M = *InitialC.begin()->getFunction().getParent();
   ProfileSummaryInfo *PSI = MAM.getCachedResult<ProfileSummaryAnalysis>(M);
 
+  if (!ImportedFunctionsStats &&
+      InlinerFunctionImportStats != InlinerFunctionImportStatsOpts::No) {
+    ImportedFunctionsStats =
+        llvm::make_unique<ImportedFunctionsInliningStatistics>();
+    ImportedFunctionsStats->setModuleInfo(M);
+  }
+
   // We use a single common worklist for calls across the entire SCC. We
   // process these in-order and append new calls introduced during inlining to
   // the end.
   //
   // Note that this particular order of processing is actually critical to
   // avoid very bad behaviors. Consider *highly connected* call graphs where
   // each function contains a small amonut of code and a couple of calls to
   // other functions. Because the LLVM inliner is fundamentally a bottom-up
for (; i < (int)Calls.size() && Calls[i].first.getCaller() == &F; ++i) {
         int NewHistoryID = InlineHistory.size();
         InlineHistory.push_back({&Callee, InlineHistoryID});
         for (CallSite &CS : reverse(IFI.InlinedCallSites))
           if (Function *NewCallee = CS.getCalledFunction())
             if (!NewCallee->isDeclaration())
               Calls.push_back({CS, NewHistoryID});
       }
 
+      if (InlinerFunctionImportStats != InlinerFunctionImportStatsOpts::No)
+        ImportedFunctionsStats->recordInline(F, Callee);
+
       // Merge the attributes based on the inlining.
       AttributeFuncs::mergeAttributesForInlining(F, Callee);
 
       // For local functions, check whether this makes the callee trivially
       // dead. In that case, we can drop the body of the function eagerly
       // which may reduce the number of callers of other functions to one,
       // changing inline cost thresholds.
       if (Callee.hasLocalLinkage()) {

test/Transforms/Inline/inline_stats.ll

+; First with legacy PM
 ; RUN: opt -S -inline -inliner-function-import-stats=basic < %s 2>&1 | FileCheck %s -check-prefix=CHECK-BASIC -check-prefix=CHECK
 ; RUN: opt -S -inline -inliner-function-import-stats=verbose < %s 2>&1 | FileCheck %s -check-prefix="CHECK-VERBOSE" -check-prefix=CHECK
 
+; Do again with new PM
+; RUN: opt -S -passes=inline -inliner-function-import-stats=basic < %s 2>&1 | FileCheck %s -check-prefix=CHECK-BASIC -check-prefix=CHECK
+; RUN: opt -S -passes=inline -inliner-function-import-stats=verbose < %s 2>&1 | FileCheck %s -check-prefix="CHECK-VERBOSE" -check-prefix=CHECK
+
 ; CHECK: ------- Dumping inliner stats for [<stdin>] -------
 ; CHECK-BASIC-NOT: -- List of inlined functions:
 ; CHECK-BASIC-NOT: -- Inlined not imported function
 ; CHECK-VERBOSE: -- List of inlined functions:
 ; CHECK-VERBOSE: Inlined not imported function [internal2]: #inlines = 6, #inlines_to_importing_module = 2
 ; CHECK-VERBOSE: Inlined imported function [external2]: #inlines = 4, #inlines_to_importing_module = 1
 ; CHECK-VERBOSE: Inlined imported function [external1]: #inlines = 3, #inlines_to_importing_module = 2
 ; CHECK-VERBOSE: Inlined imported function [external5]: #inlines = 1, #inlines_to_importing_module = 1