llvm/lib/Analysis/ImportedFunctionsInliningStatistics.cpp

   1 //===-- ImportedFunctionsInliningStats.cpp ----------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 // Generating inliner statistics for imported functions, mostly useful for
   9 // ThinLTO.
  10 //===----------------------------------------------------------------------===//
  11
  12 #include "llvm/Analysis/Utils/ImportedFunctionsInliningStatistics.h"
  13 #include "llvm/ADT/STLExtras.h"
  14 #include "llvm/IR/Function.h"
  15 #include "llvm/IR/Module.h"
  16 #include "llvm/Support/CommandLine.h"
  17 #include "llvm/Support/Debug.h"
  18 #include "llvm/Support/raw_ostream.h"
  19 #include <algorithm>
  20 #include <iomanip>
  21 #include <sstream>
  22 #include <string>
  23
  24 using namespace llvm;
  25
  26 cl::opt<InlinerFunctionImportStatsOpts> InlinerFunctionImportStats(
  27     "inliner-function-import-stats",
  28     cl::init(InlinerFunctionImportStatsOpts::No),
  29     cl::values(clEnumValN(InlinerFunctionImportStatsOpts::Basic, "basic",
  30                           "basic statistics"),
  31                clEnumValN(InlinerFunctionImportStatsOpts::Verbose, "verbose",
  32                           "printing of statistics for each inlined function")),
  33     cl::Hidden, cl::desc("Enable inliner stats for imported functions"));
  34
  35 ImportedFunctionsInliningStatistics::InlineGraphNode &
  36 ImportedFunctionsInliningStatistics::createInlineGraphNode(const Function &F) {
  37
  38   auto &ValueLookup = NodesMap[F.getName()];
  39   if (!ValueLookup) {
  40     ValueLookup = std::make_unique<InlineGraphNode>();
  41     ValueLookup->Imported = F.hasMetadata("thinlto_src_module");
  42   }
  43   return *ValueLookup;
  44 }
  45
  46 void ImportedFunctionsInliningStatistics::recordInline(const Function &Caller,
  47                                                        const Function &Callee) {
  48
  49   InlineGraphNode &CallerNode = createInlineGraphNode(Caller);
  50   InlineGraphNode &CalleeNode = createInlineGraphNode(Callee);
  51   CalleeNode.NumberOfInlines++;
  52
  53   if (!CallerNode.Imported && !CalleeNode.Imported) {
  54     // Direct inline from not imported callee to not imported caller, so we
  55     // don't have to add this to graph. It might be very helpful if you wanna
  56     // get the inliner statistics in compile step where there are no imported
  57     // functions. In this case the graph would be empty.
  58     CalleeNode.NumberOfRealInlines++;
  59     return;
  60   }
  61
  62   CallerNode.InlinedCallees.push_back(&CalleeNode);
  63   if (!CallerNode.Imported) {
  64     // We could avoid second lookup, but it would make the code ultra ugly.
  65     auto It = NodesMap.find(Caller.getName());
  66     assert(It != NodesMap.end() && "The node should be already there.");
  67     // Save Caller as a starting node for traversal. The string has to be one
  68     // from map because Caller can disappear (and function name with it).
  69     NonImportedCallers.push_back(It->first());
  70   }
  71 }
  72
  73 void ImportedFunctionsInliningStatistics::setModuleInfo(const Module &M) {
  74   ModuleName = M.getName();
  75   for (const auto &F : M.functions()) {
  76     if (F.isDeclaration())
  77       continue;
  78     AllFunctions++;
  79     ImportedFunctions += int(F.hasMetadata("thinlto_src_module"));
  80   }
  81 }
  82 static std::string getStatString(const char *Msg, int32_t Fraction, int32_t All,
  83                                  const char *PercentageOfMsg,
  84                                  bool LineEnd = true) {
  85   double Result = 0;
  86   if (All != 0)
  87     Result = 100 * static_cast<double>(Fraction) / All;
  88
  89   std::stringstream Str;
  90   Str << std::setprecision(4) << Msg << ": " << Fraction << " [" << Result
  91       << "% of " << PercentageOfMsg << "]";
  92   if (LineEnd)
  93     Str << "\n";
  94   return Str.str();
  95 }
  96
  97 void ImportedFunctionsInliningStatistics::dump(const bool Verbose) {
  98   calculateRealInlines();
  99   NonImportedCallers.clear();
 100
 101   int32_t InlinedImportedFunctionsCount = 0;
 102   int32_t InlinedNotImportedFunctionsCount = 0;
 103
 104   int32_t InlinedImportedFunctionsToImportingModuleCount = 0;
 105   int32_t InlinedNotImportedFunctionsToImportingModuleCount = 0;
 106
 107   const auto SortedNodes = getSortedNodes();
 108   std::string Out;
 109   Out.reserve(5000);
 110   raw_string_ostream Ostream(Out);
 111
 112   Ostream << "------- Dumping inliner stats for [" << ModuleName
 113           << "] -------\n";
 114
 115   if (Verbose)
 116     Ostream << "-- List of inlined functions:\n";
 117
 118   for (const auto &Node : SortedNodes) {
 119     assert(Node->second->NumberOfInlines >= Node->second->NumberOfRealInlines);
 120     if (Node->second->NumberOfInlines == 0)
 121       continue;
 122
 123     if (Node->second->Imported) {
 124       InlinedImportedFunctionsCount++;
 125       InlinedImportedFunctionsToImportingModuleCount +=
 126           int(Node->second->NumberOfRealInlines > 0);
 127     } else {
 128       InlinedNotImportedFunctionsCount++;
 129       InlinedNotImportedFunctionsToImportingModuleCount +=
 130           int(Node->second->NumberOfRealInlines > 0);
 131     }
 132
 133     if (Verbose)
 134       Ostream << "Inlined "
 135               << (Node->second->Imported ? "imported " : "not imported ")
 136               << "function [" << Node->first() << "]"
 137               << ": #inlines = " << Node->second->NumberOfInlines
 138               << ", #inlines_to_importing_module = "
 139               << Node->second->NumberOfRealInlines << "\n";
 140   }
 141
 142   auto InlinedFunctionsCount =
 143       InlinedImportedFunctionsCount + InlinedNotImportedFunctionsCount;
 144   auto NotImportedFuncCount = AllFunctions - ImportedFunctions;
 145   auto ImportedNotInlinedIntoModule =
 146       ImportedFunctions - InlinedImportedFunctionsToImportingModuleCount;
 147
 148   Ostream << "-- Summary:\n"
 149           << "All functions: " << AllFunctions
 150           << ", imported functions: " << ImportedFunctions << "\n"
 151           << getStatString("inlined functions", InlinedFunctionsCount,
 152                            AllFunctions, "all functions")
 153           << getStatString("imported functions inlined anywhere",
 154                            InlinedImportedFunctionsCount, ImportedFunctions,
 155                            "imported functions")
 156           << getStatString("imported functions inlined into importing module",
 157                            InlinedImportedFunctionsToImportingModuleCount,
 158                            ImportedFunctions, "imported functions",
 159                            /*LineEnd=*/false)
 160           << getStatString(", remaining", ImportedNotInlinedIntoModule,
 161                            ImportedFunctions, "imported functions")
 162           << getStatString("non-imported functions inlined anywhere",
 163                            InlinedNotImportedFunctionsCount,
 164                            NotImportedFuncCount, "non-imported functions")
 165           << getStatString(
 166                  "non-imported functions inlined into importing module",
 167                  InlinedNotImportedFunctionsToImportingModuleCount,
 168                  NotImportedFuncCount, "non-imported functions");
 169   Ostream.flush();
 170   dbgs() << Out;
 171 }
 172
 173 void ImportedFunctionsInliningStatistics::calculateRealInlines() {
 174   // Removing duplicated Callers.
 175   llvm::sort(NonImportedCallers);
 176   NonImportedCallers.erase(
 177       std::unique(NonImportedCallers.begin(), NonImportedCallers.end()),
 178       NonImportedCallers.end());
 179
 180   for (const auto &Name : NonImportedCallers) {
 181     auto &Node = *NodesMap[Name];
 182     if (!Node.Visited)
 183       dfs(Node);
 184   }
 185 }
 186
 187 void ImportedFunctionsInliningStatistics::dfs(InlineGraphNode &GraphNode) {
 188   assert(!GraphNode.Visited);
 189   GraphNode.Visited = true;
 190   for (auto *const InlinedFunctionNode : GraphNode.InlinedCallees) {
 191     InlinedFunctionNode->NumberOfRealInlines++;
 192     if (!InlinedFunctionNode->Visited)
 193       dfs(*InlinedFunctionNode);
 194   }
 195 }
 196
 197 ImportedFunctionsInliningStatistics::SortedNodesTy
 198 ImportedFunctionsInliningStatistics::getSortedNodes() {
 199   SortedNodesTy SortedNodes;
 200   SortedNodes.reserve(NodesMap.size());
 201   for (const NodesMapTy::value_type &Node : NodesMap)
 202     SortedNodes.push_back(&Node);
 203
 204   llvm::sort(SortedNodes, [&](const SortedNodesTy::value_type &Lhs,
 205                               const SortedNodesTy::value_type &Rhs) {
 206     if (Lhs->second->NumberOfInlines != Rhs->second->NumberOfInlines)
 207       return Lhs->second->NumberOfInlines > Rhs->second->NumberOfInlines;
 208     if (Lhs->second->NumberOfRealInlines != Rhs->second->NumberOfRealInlines)
 209       return Lhs->second->NumberOfRealInlines >
 210              Rhs->second->NumberOfRealInlines;
 211     return Lhs->first() < Rhs->first();
 212   });
 213   return SortedNodes;
 214 }