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 <iomanip>
  20 #include <sstream>
  21 #include <string>
  22
  23 using namespace llvm;
  24
  25 namespace llvm {
  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 } // namespace llvm
  35
  36 ImportedFunctionsInliningStatistics::InlineGraphNode &
  37 ImportedFunctionsInliningStatistics::createInlineGraphNode(const Function &F) {
  38
  39   auto &ValueLookup = NodesMap[F.getName()];
  40   if (!ValueLookup) {
  41     ValueLookup = std::make_unique<InlineGraphNode>();
  42     ValueLookup->Imported = F.hasMetadata("thinlto_src_module");
  43   }
  44   return *ValueLookup;
  45 }
  46
  47 void ImportedFunctionsInliningStatistics::recordInline(const Function &Caller,
  48                                                        const Function &Callee) {
  49
  50   InlineGraphNode &CallerNode = createInlineGraphNode(Caller);
  51   InlineGraphNode &CalleeNode = createInlineGraphNode(Callee);
  52   CalleeNode.NumberOfInlines++;
  53
  54   if (!CallerNode.Imported && !CalleeNode.Imported) {
  55     // Direct inline from not imported callee to not imported caller, so we
  56     // don't have to add this to graph. It might be very helpful if you wanna
  57     // get the inliner statistics in compile step where there are no imported
  58     // functions. In this case the graph would be empty.
  59     CalleeNode.NumberOfRealInlines++;
  60     return;
  61   }
  62
  63   CallerNode.InlinedCallees.push_back(&CalleeNode);
  64   if (!CallerNode.Imported) {
  65     // We could avoid second lookup, but it would make the code ultra ugly.
  66     auto It = NodesMap.find(Caller.getName());
  67     assert(It != NodesMap.end() && "The node should be already there.");
  68     // Save Caller as a starting node for traversal. The string has to be one
  69     // from map because Caller can disappear (and function name with it).
  70     NonImportedCallers.push_back(It->first());
  71   }
  72 }
  73
  74 void ImportedFunctionsInliningStatistics::setModuleInfo(const Module &M) {
  75   ModuleName = M.getName();
  76   for (const auto &F : M.functions()) {
  77     if (F.isDeclaration())
  78       continue;
  79     AllFunctions++;
  80     ImportedFunctions += int(F.hasMetadata("thinlto_src_module"));
  81   }
  82 }
  83 static std::string getStatString(const char *Msg, int32_t Fraction, int32_t All,
  84                                  const char *PercentageOfMsg,
  85                                  bool LineEnd = true) {
  86   double Result = 0;
  87   if (All != 0)
  88     Result = 100 * static_cast<double>(Fraction) / All;
  89
  90   std::stringstream Str;
  91   Str << std::setprecision(4) << Msg << ": " << Fraction << " [" << Result
  92       << "% of " << PercentageOfMsg << "]";
  93   if (LineEnd)
  94     Str << "\n";
  95   return Str.str();
  96 }
  97
  98 void ImportedFunctionsInliningStatistics::dump(const bool Verbose) {
  99   calculateRealInlines();
 100   NonImportedCallers.clear();
 101
 102   int32_t InlinedImportedFunctionsCount = 0;
 103   int32_t InlinedNotImportedFunctionsCount = 0;
 104
 105   int32_t InlinedImportedFunctionsToImportingModuleCount = 0;
 106   int32_t InlinedNotImportedFunctionsToImportingModuleCount = 0;
 107
 108   const auto SortedNodes = getSortedNodes();
 109   std::string Out;
 110   Out.reserve(5000);
 111   raw_string_ostream Ostream(Out);
 112
 113   Ostream << "------- Dumping inliner stats for [" << ModuleName
 114           << "] -------\n";
 115
 116   if (Verbose)
 117     Ostream << "-- List of inlined functions:\n";
 118
 119   for (const auto &Node : SortedNodes) {
 120     assert(Node->second->NumberOfInlines >= Node->second->NumberOfRealInlines);
 121     if (Node->second->NumberOfInlines == 0)
 122       continue;
 123
 124     if (Node->second->Imported) {
 125       InlinedImportedFunctionsCount++;
 126       InlinedImportedFunctionsToImportingModuleCount +=
 127           int(Node->second->NumberOfRealInlines > 0);
 128     } else {
 129       InlinedNotImportedFunctionsCount++;
 130       InlinedNotImportedFunctionsToImportingModuleCount +=
 131           int(Node->second->NumberOfRealInlines > 0);
 132     }
 133
 134     if (Verbose)
 135       Ostream << "Inlined "
 136               << (Node->second->Imported ? "imported " : "not imported ")
 137               << "function [" << Node->first() << "]"
 138               << ": #inlines = " << Node->second->NumberOfInlines
 139               << ", #inlines_to_importing_module = "
 140               << Node->second->NumberOfRealInlines << "\n";
 141   }
 142
 143   auto InlinedFunctionsCount =
 144       InlinedImportedFunctionsCount + InlinedNotImportedFunctionsCount;
 145   auto NotImportedFuncCount = AllFunctions - ImportedFunctions;
 146   auto ImportedNotInlinedIntoModule =
 147       ImportedFunctions - InlinedImportedFunctionsToImportingModuleCount;
 148
 149   Ostream << "-- Summary:\n"
 150           << "All functions: " << AllFunctions
 151           << ", imported functions: " << ImportedFunctions << "\n"
 152           << getStatString("inlined functions", InlinedFunctionsCount,
 153                            AllFunctions, "all functions")
 154           << getStatString("imported functions inlined anywhere",
 155                            InlinedImportedFunctionsCount, ImportedFunctions,
 156                            "imported functions")
 157           << getStatString("imported functions inlined into importing module",
 158                            InlinedImportedFunctionsToImportingModuleCount,
 159                            ImportedFunctions, "imported functions",
 160                            /*LineEnd=*/false)
 161           << getStatString(", remaining", ImportedNotInlinedIntoModule,
 162                            ImportedFunctions, "imported functions")
 163           << getStatString("non-imported functions inlined anywhere",
 164                            InlinedNotImportedFunctionsCount,
 165                            NotImportedFuncCount, "non-imported functions")
 166           << getStatString(
 167                  "non-imported functions inlined into importing module",
 168                  InlinedNotImportedFunctionsToImportingModuleCount,
 169                  NotImportedFuncCount, "non-imported functions");
 170   Ostream.flush();
 171   dbgs() << Out;
 172 }
 173
 174 void ImportedFunctionsInliningStatistics::calculateRealInlines() {
 175   // Removing duplicated Callers.
 176   llvm::sort(NonImportedCallers);
 177   NonImportedCallers.erase(llvm::unique(NonImportedCallers),
 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 }