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