unittests/Analysis/ProfileSummaryInfoTest.cpp

   1 //===- ProfileSummaryInfoTest.cpp - ProfileSummaryInfo unit tests ---------===//
   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
   9 #include "llvm/Analysis/ProfileSummaryInfo.h"
  10 #include "llvm/Analysis/BlockFrequencyInfo.h"
  11 #include "llvm/Analysis/BranchProbabilityInfo.h"
  12 #include "llvm/Analysis/LoopInfo.h"
  13 #include "llvm/AsmParser/Parser.h"
  14 #include "llvm/IR/BasicBlock.h"
  15 #include "llvm/IR/CallSite.h"
  16 #include "llvm/IR/Dominators.h"
  17 #include "llvm/IR/Function.h"
  18 #include "llvm/IR/LLVMContext.h"
  19 #include "llvm/IR/MDBuilder.h"
  20 #include "llvm/IR/Module.h"
  21 #include "llvm/Support/DataTypes.h"
  22 #include "llvm/Support/FormatVariadic.h"
  23 #include "llvm/Support/SourceMgr.h"
  24 #include "llvm/Support/raw_ostream.h"
  25 #include "gtest/gtest.h"
  26
  27 namespace llvm {
  28 namespace {
  29
  30 class ProfileSummaryInfoTest : public testing::Test {
  31 protected:
  32   LLVMContext C;
  33   std::unique_ptr<BranchProbabilityInfo> BPI;
  34   std::unique_ptr<DominatorTree> DT;
  35   std::unique_ptr<LoopInfo> LI;
  36
  37   ProfileSummaryInfo buildPSI(Module *M) {
  38     return ProfileSummaryInfo(*M);
  39   }
  40   BlockFrequencyInfo buildBFI(Function &F) {
  41     DT.reset(new DominatorTree(F));
  42     LI.reset(new LoopInfo(*DT));
  43     BPI.reset(new BranchProbabilityInfo(F, *LI));
  44     return BlockFrequencyInfo(F, *BPI, *LI);
  45   }
  46   std::unique_ptr<Module> makeLLVMModule(const char *ProfKind = nullptr) {
  47     const char *ModuleString =
  48         "define i32 @g(i32 %x) !prof !21 {{\n"
  49         "  ret i32 0\n"
  50         "}\n"
  51         "define i32 @h(i32 %x) !prof !22 {{\n"
  52         "  ret i32 0\n"
  53         "}\n"
  54         "define i32 @f(i32 %x) !prof !20 {{\n"
  55         "bb0:\n"
  56         "  %y1 = icmp eq i32 %x, 0 \n"
  57         "  br i1 %y1, label %bb1, label %bb2, !prof !23 \n"
  58         "bb1:\n"
  59         "  %z1 = call i32 @g(i32 %x)\n"
  60         "  br label %bb3\n"
  61         "bb2:\n"
  62         "  %z2 = call i32 @h(i32 %x)\n"
  63         "  br label %bb3\n"
  64         "bb3:\n"
  65         "  %y2 = phi i32 [0, %bb1], [1, %bb2] \n"
  66         "  ret i32 %y2\n"
  67         "}\n"
  68         "!20 = !{{!\"function_entry_count\", i64 400}\n"
  69         "!21 = !{{!\"function_entry_count\", i64 1}\n"
  70         "!22 = !{{!\"function_entry_count\", i64 100}\n"
  71         "!23 = !{{!\"branch_weights\", i32 64, i32 4}\n"
  72         "{0}";
  73     const char *SummaryString = "!llvm.module.flags = !{{!1}"
  74                                 "!1 = !{{i32 1, !\"ProfileSummary\", !2}"
  75                                 "!2 = !{{!3, !4, !5, !6, !7, !8, !9, !10}"
  76                                 "!3 = !{{!\"ProfileFormat\", !\"{0}\"}"
  77                                 "!4 = !{{!\"TotalCount\", i64 10000}"
  78                                 "!5 = !{{!\"MaxCount\", i64 10}"
  79                                 "!6 = !{{!\"MaxInternalCount\", i64 1}"
  80                                 "!7 = !{{!\"MaxFunctionCount\", i64 1000}"
  81                                 "!8 = !{{!\"NumCounts\", i64 3}"
  82                                 "!9 = !{{!\"NumFunctions\", i64 3}"
  83                                 "!10 = !{{!\"DetailedSummary\", !11}"
  84                                 "!11 = !{{!12, !13, !14}"
  85                                 "!12 = !{{i32 10000, i64 1000, i32 1}"
  86                                 "!13 = !{{i32 999000, i64 300, i32 3}"
  87                                 "!14 = !{{i32 999999, i64 5, i32 10}";
  88     SMDiagnostic Err;
  89     if (ProfKind)
  90       return parseAssemblyString(
  91           formatv(ModuleString, formatv(SummaryString, ProfKind).str()).str(),
  92           Err, C);
  93     else
  94       return parseAssemblyString(formatv(ModuleString, "").str(), Err, C);
  95   }
  96 };
  97
  98 TEST_F(ProfileSummaryInfoTest, TestNoProfile) {
  99   auto M = makeLLVMModule(/*ProfKind=*/nullptr);
 100   Function *F = M->getFunction("f");
 101
 102   ProfileSummaryInfo PSI = buildPSI(M.get());
 103   EXPECT_FALSE(PSI.hasProfileSummary());
 104   EXPECT_FALSE(PSI.hasSampleProfile());
 105   EXPECT_FALSE(PSI.hasInstrumentationProfile());
 106   // In the absence of profiles, is{Hot|Cold}X methods should always return
 107   // false.
 108   EXPECT_FALSE(PSI.isHotCount(1000));
 109   EXPECT_FALSE(PSI.isHotCount(0));
 110   EXPECT_FALSE(PSI.isColdCount(1000));
 111   EXPECT_FALSE(PSI.isColdCount(0));
 112
 113   EXPECT_FALSE(PSI.isFunctionEntryHot(F));
 114   EXPECT_FALSE(PSI.isFunctionEntryCold(F));
 115
 116   BasicBlock &BB0 = F->getEntryBlock();
 117   BasicBlock *BB1 = BB0.getTerminator()->getSuccessor(0);
 118
 119   BlockFrequencyInfo BFI = buildBFI(*F);
 120   EXPECT_FALSE(PSI.isHotBlock(&BB0, &BFI));
 121   EXPECT_FALSE(PSI.isColdBlock(&BB0, &BFI));
 122
 123   CallSite CS1(BB1->getFirstNonPHI());
 124   EXPECT_FALSE(PSI.isHotCallSite(CS1, &BFI));
 125   EXPECT_FALSE(PSI.isColdCallSite(CS1, &BFI));
 126 }
 127 TEST_F(ProfileSummaryInfoTest, TestCommon) {
 128   auto M = makeLLVMModule("InstrProf");
 129   Function *F = M->getFunction("f");
 130   Function *G = M->getFunction("g");
 131   Function *H = M->getFunction("h");
 132
 133   ProfileSummaryInfo PSI = buildPSI(M.get());
 134   EXPECT_TRUE(PSI.hasProfileSummary());
 135   EXPECT_TRUE(PSI.isHotCount(400));
 136   EXPECT_TRUE(PSI.isColdCount(2));
 137   EXPECT_FALSE(PSI.isColdCount(100));
 138   EXPECT_FALSE(PSI.isHotCount(100));
 139
 140   EXPECT_TRUE(PSI.isFunctionEntryHot(F));
 141   EXPECT_FALSE(PSI.isFunctionEntryHot(G));
 142   EXPECT_FALSE(PSI.isFunctionEntryHot(H));
 143 }
 144
 145 TEST_F(ProfileSummaryInfoTest, InstrProf) {
 146   auto M = makeLLVMModule("InstrProf");
 147   Function *F = M->getFunction("f");
 148   ProfileSummaryInfo PSI = buildPSI(M.get());
 149   EXPECT_TRUE(PSI.hasProfileSummary());
 150   EXPECT_TRUE(PSI.hasInstrumentationProfile());
 151
 152   BasicBlock &BB0 = F->getEntryBlock();
 153   BasicBlock *BB1 = BB0.getTerminator()->getSuccessor(0);
 154   BasicBlock *BB2 = BB0.getTerminator()->getSuccessor(1);
 155   BasicBlock *BB3 = BB1->getSingleSuccessor();
 156
 157   BlockFrequencyInfo BFI = buildBFI(*F);
 158   EXPECT_TRUE(PSI.isHotBlock(&BB0, &BFI));
 159   EXPECT_TRUE(PSI.isHotBlock(BB1, &BFI));
 160   EXPECT_FALSE(PSI.isHotBlock(BB2, &BFI));
 161   EXPECT_TRUE(PSI.isHotBlock(BB3, &BFI));
 162
 163   CallSite CS1(BB1->getFirstNonPHI());
 164   auto *CI2 = BB2->getFirstNonPHI();
 165   CallSite CS2(CI2);
 166
 167   EXPECT_TRUE(PSI.isHotCallSite(CS1, &BFI));
 168   EXPECT_FALSE(PSI.isHotCallSite(CS2, &BFI));
 169
 170   // Test that adding an MD_prof metadata with a hot count on CS2 does not
 171   // change its hotness as it has no effect in instrumented profiling.
 172   MDBuilder MDB(M->getContext());
 173   CI2->setMetadata(llvm::LLVMContext::MD_prof, MDB.createBranchWeights({400}));
 174   EXPECT_FALSE(PSI.isHotCallSite(CS2, &BFI));
 175 }
 176
 177 TEST_F(ProfileSummaryInfoTest, SampleProf) {
 178   auto M = makeLLVMModule("SampleProfile");
 179   Function *F = M->getFunction("f");
 180   ProfileSummaryInfo PSI = buildPSI(M.get());
 181   EXPECT_TRUE(PSI.hasProfileSummary());
 182   EXPECT_TRUE(PSI.hasSampleProfile());
 183
 184   BasicBlock &BB0 = F->getEntryBlock();
 185   BasicBlock *BB1 = BB0.getTerminator()->getSuccessor(0);
 186   BasicBlock *BB2 = BB0.getTerminator()->getSuccessor(1);
 187   BasicBlock *BB3 = BB1->getSingleSuccessor();
 188
 189   BlockFrequencyInfo BFI = buildBFI(*F);
 190   EXPECT_TRUE(PSI.isHotBlock(&BB0, &BFI));
 191   EXPECT_TRUE(PSI.isHotBlock(BB1, &BFI));
 192   EXPECT_FALSE(PSI.isHotBlock(BB2, &BFI));
 193   EXPECT_TRUE(PSI.isHotBlock(BB3, &BFI));
 194
 195   CallSite CS1(BB1->getFirstNonPHI());
 196   auto *CI2 = BB2->getFirstNonPHI();
 197   // Manually attach branch weights metadata to the call instruction.
 198   SmallVector<uint32_t, 1> Weights;
 199   Weights.push_back(1000);
 200   MDBuilder MDB(M->getContext());
 201   CI2->setMetadata(LLVMContext::MD_prof, MDB.createBranchWeights(Weights));
 202   CallSite CS2(CI2);
 203
 204   EXPECT_FALSE(PSI.isHotCallSite(CS1, &BFI));
 205   EXPECT_TRUE(PSI.isHotCallSite(CS2, &BFI));
 206
 207   // Test that CS2 is considered hot when it gets an MD_prof metadata with
 208   // weights that exceed the hot count threshold.
 209   CI2->setMetadata(llvm::LLVMContext::MD_prof, MDB.createBranchWeights({400}));
 210   EXPECT_TRUE(PSI.isHotCallSite(CS2, &BFI));
 211 }
 212
 213 } // end anonymous namespace
 214 } // end namespace llvm