unittests/IR/DominatorTreeTest.cpp

   1 //===- llvm/unittests/IR/DominatorTreeTest.cpp - Constants unit tests -----===//
   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
  10 #include "llvm/IR/Dominators.h"
  11 #include "llvm/Analysis/PostDominators.h"
  12 #include "llvm/AsmParser/Parser.h"
  13 #include "llvm/IR/Constants.h"
  14 #include "llvm/IR/Instructions.h"
  15 #include "llvm/IR/LLVMContext.h"
  16 #include "llvm/IR/Module.h"
  17 #include "llvm/IR/LegacyPassManager.h"
  18 #include "llvm/Support/SourceMgr.h"
  19 #include "gtest/gtest.h"
  20
  21 using namespace llvm;
  22
  23 namespace llvm {
  24   void initializeDPassPass(PassRegistry&);
  25
  26   namespace {
  27     struct DPass : public FunctionPass {
  28       static char ID;
  29       bool runOnFunction(Function &F) override {
  30         DominatorTree *DT =
  31             &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
  32         PostDominatorTree *PDT = &getAnalysis<PostDominatorTree>();
  33         Function::iterator FI = F.begin();
  34
  35         BasicBlock *BB0 = FI++;
  36         BasicBlock::iterator BBI = BB0->begin();
  37         Instruction *Y1 = BBI++;
  38         Instruction *Y2 = BBI++;
  39         Instruction *Y3 = BBI++;
  40
  41         BasicBlock *BB1 = FI++;
  42         BBI = BB1->begin();
  43         Instruction *Y4 = BBI++;
  44
  45         BasicBlock *BB2 = FI++;
  46         BBI = BB2->begin();
  47         Instruction *Y5 = BBI++;
  48
  49         BasicBlock *BB3 = FI++;
  50         BBI = BB3->begin();
  51         Instruction *Y6 = BBI++;
  52         Instruction *Y7 = BBI++;
  53
  54         BasicBlock *BB4 = FI++;
  55         BBI = BB4->begin();
  56         Instruction *Y8 = BBI++;
  57         Instruction *Y9 = BBI++;
  58
  59         // Reachability
  60         EXPECT_TRUE(DT->isReachableFromEntry(BB0));
  61         EXPECT_TRUE(DT->isReachableFromEntry(BB1));
  62         EXPECT_TRUE(DT->isReachableFromEntry(BB2));
  63         EXPECT_FALSE(DT->isReachableFromEntry(BB3));
  64         EXPECT_TRUE(DT->isReachableFromEntry(BB4));
  65
  66         // BB dominance
  67         EXPECT_TRUE(DT->dominates(BB0, BB0));
  68         EXPECT_TRUE(DT->dominates(BB0, BB1));
  69         EXPECT_TRUE(DT->dominates(BB0, BB2));
  70         EXPECT_TRUE(DT->dominates(BB0, BB3));
  71         EXPECT_TRUE(DT->dominates(BB0, BB4));
  72
  73         EXPECT_FALSE(DT->dominates(BB1, BB0));
  74         EXPECT_TRUE(DT->dominates(BB1, BB1));
  75         EXPECT_FALSE(DT->dominates(BB1, BB2));
  76         EXPECT_TRUE(DT->dominates(BB1, BB3));
  77         EXPECT_FALSE(DT->dominates(BB1, BB4));
  78
  79         EXPECT_FALSE(DT->dominates(BB2, BB0));
  80         EXPECT_FALSE(DT->dominates(BB2, BB1));
  81         EXPECT_TRUE(DT->dominates(BB2, BB2));
  82         EXPECT_TRUE(DT->dominates(BB2, BB3));
  83         EXPECT_FALSE(DT->dominates(BB2, BB4));
  84
  85         EXPECT_FALSE(DT->dominates(BB3, BB0));
  86         EXPECT_FALSE(DT->dominates(BB3, BB1));
  87         EXPECT_FALSE(DT->dominates(BB3, BB2));
  88         EXPECT_TRUE(DT->dominates(BB3, BB3));
  89         EXPECT_FALSE(DT->dominates(BB3, BB4));
  90
  91         // BB proper dominance
  92         EXPECT_FALSE(DT->properlyDominates(BB0, BB0));
  93         EXPECT_TRUE(DT->properlyDominates(BB0, BB1));
  94         EXPECT_TRUE(DT->properlyDominates(BB0, BB2));
  95         EXPECT_TRUE(DT->properlyDominates(BB0, BB3));
  96
  97         EXPECT_FALSE(DT->properlyDominates(BB1, BB0));
  98         EXPECT_FALSE(DT->properlyDominates(BB1, BB1));
  99         EXPECT_FALSE(DT->properlyDominates(BB1, BB2));
 100         EXPECT_TRUE(DT->properlyDominates(BB1, BB3));
 101
 102         EXPECT_FALSE(DT->properlyDominates(BB2, BB0));
 103         EXPECT_FALSE(DT->properlyDominates(BB2, BB1));
 104         EXPECT_FALSE(DT->properlyDominates(BB2, BB2));
 105         EXPECT_TRUE(DT->properlyDominates(BB2, BB3));
 106
 107         EXPECT_FALSE(DT->properlyDominates(BB3, BB0));
 108         EXPECT_FALSE(DT->properlyDominates(BB3, BB1));
 109         EXPECT_FALSE(DT->properlyDominates(BB3, BB2));
 110         EXPECT_FALSE(DT->properlyDominates(BB3, BB3));
 111
 112         // Instruction dominance in the same reachable BB
 113         EXPECT_FALSE(DT->dominates(Y1, Y1));
 114         EXPECT_TRUE(DT->dominates(Y1, Y2));
 115         EXPECT_FALSE(DT->dominates(Y2, Y1));
 116         EXPECT_FALSE(DT->dominates(Y2, Y2));
 117
 118         // Instruction dominance in the same unreachable BB
 119         EXPECT_TRUE(DT->dominates(Y6, Y6));
 120         EXPECT_TRUE(DT->dominates(Y6, Y7));
 121         EXPECT_TRUE(DT->dominates(Y7, Y6));
 122         EXPECT_TRUE(DT->dominates(Y7, Y7));
 123
 124         // Invoke
 125         EXPECT_TRUE(DT->dominates(Y3, Y4));
 126         EXPECT_FALSE(DT->dominates(Y3, Y5));
 127
 128         // Phi
 129         EXPECT_TRUE(DT->dominates(Y2, Y9));
 130         EXPECT_FALSE(DT->dominates(Y3, Y9));
 131         EXPECT_FALSE(DT->dominates(Y8, Y9));
 132
 133         // Anything dominates unreachable
 134         EXPECT_TRUE(DT->dominates(Y1, Y6));
 135         EXPECT_TRUE(DT->dominates(Y3, Y6));
 136
 137         // Unreachable doesn't dominate reachable
 138         EXPECT_FALSE(DT->dominates(Y6, Y1));
 139
 140         // Instruction, BB dominance
 141         EXPECT_FALSE(DT->dominates(Y1, BB0));
 142         EXPECT_TRUE(DT->dominates(Y1, BB1));
 143         EXPECT_TRUE(DT->dominates(Y1, BB2));
 144         EXPECT_TRUE(DT->dominates(Y1, BB3));
 145         EXPECT_TRUE(DT->dominates(Y1, BB4));
 146
 147         EXPECT_FALSE(DT->dominates(Y3, BB0));
 148         EXPECT_TRUE(DT->dominates(Y3, BB1));
 149         EXPECT_FALSE(DT->dominates(Y3, BB2));
 150         EXPECT_TRUE(DT->dominates(Y3, BB3));
 151         EXPECT_FALSE(DT->dominates(Y3, BB4));
 152
 153         EXPECT_TRUE(DT->dominates(Y6, BB3));
 154
 155         // Post dominance.
 156         EXPECT_TRUE(PDT->dominates(BB0, BB0));
 157         EXPECT_FALSE(PDT->dominates(BB1, BB0));
 158         EXPECT_FALSE(PDT->dominates(BB2, BB0));
 159         EXPECT_FALSE(PDT->dominates(BB3, BB0));
 160         EXPECT_TRUE(PDT->dominates(BB4, BB1));
 161
 162         // Dominance descendants.
 163         SmallVector<BasicBlock *, 8> DominatedBBs, PostDominatedBBs;
 164
 165         DT->getDescendants(BB0, DominatedBBs);
 166         PDT->getDescendants(BB0, PostDominatedBBs);
 167         EXPECT_EQ(DominatedBBs.size(), 4UL);
 168         EXPECT_EQ(PostDominatedBBs.size(), 1UL);
 169
 170         // BB3 is unreachable. It should have no dominators nor postdominators.
 171         DominatedBBs.clear();
 172         PostDominatedBBs.clear();
 173         DT->getDescendants(BB3, DominatedBBs);
 174         DT->getDescendants(BB3, PostDominatedBBs);
 175         EXPECT_EQ(DominatedBBs.size(), 0UL);
 176         EXPECT_EQ(PostDominatedBBs.size(), 0UL);
 177
 178         // Check DFS Numbers before
 179         EXPECT_EQ(DT->getNode(BB0)->getDFSNumIn(), 0UL);
 180         EXPECT_EQ(DT->getNode(BB0)->getDFSNumOut(), 7UL);
 181         EXPECT_EQ(DT->getNode(BB1)->getDFSNumIn(), 1UL);
 182         EXPECT_EQ(DT->getNode(BB1)->getDFSNumOut(), 2UL);
 183         EXPECT_EQ(DT->getNode(BB2)->getDFSNumIn(), 5UL);
 184         EXPECT_EQ(DT->getNode(BB2)->getDFSNumOut(), 6UL);
 185         EXPECT_EQ(DT->getNode(BB4)->getDFSNumIn(), 3UL);
 186         EXPECT_EQ(DT->getNode(BB4)->getDFSNumOut(), 4UL);
 187
 188         // Reattach block 3 to block 1 and recalculate
 189         BB1->getTerminator()->eraseFromParent();
 190         BranchInst::Create(BB4, BB3, ConstantInt::getTrue(F.getContext()), BB1);
 191         DT->recalculate(F);
 192
 193         // Check DFS Numbers after
 194         EXPECT_EQ(DT->getNode(BB0)->getDFSNumIn(), 0UL);
 195         EXPECT_EQ(DT->getNode(BB0)->getDFSNumOut(), 9UL);
 196         EXPECT_EQ(DT->getNode(BB1)->getDFSNumIn(), 1UL);
 197         EXPECT_EQ(DT->getNode(BB1)->getDFSNumOut(), 4UL);
 198         EXPECT_EQ(DT->getNode(BB2)->getDFSNumIn(), 7UL);
 199         EXPECT_EQ(DT->getNode(BB2)->getDFSNumOut(), 8UL);
 200         EXPECT_EQ(DT->getNode(BB3)->getDFSNumIn(), 2UL);
 201         EXPECT_EQ(DT->getNode(BB3)->getDFSNumOut(), 3UL);
 202         EXPECT_EQ(DT->getNode(BB4)->getDFSNumIn(), 5UL);
 203         EXPECT_EQ(DT->getNode(BB4)->getDFSNumOut(), 6UL);
 204
 205         return false;
 206       }
 207       void getAnalysisUsage(AnalysisUsage &AU) const override {
 208         AU.addRequired<DominatorTreeWrapperPass>();
 209         AU.addRequired<PostDominatorTree>();
 210       }
 211       DPass() : FunctionPass(ID) {
 212         initializeDPassPass(*PassRegistry::getPassRegistry());
 213       }
 214     };
 215     char DPass::ID = 0;
 216
 217     std::unique_ptr<Module> makeLLVMModule(DPass *P) {
 218       const char *ModuleStrig =
 219         "declare i32 @g()\n" \
 220         "define void @f(i32 %x) {\n" \
 221         "bb0:\n" \
 222         "  %y1 = add i32 %x, 1\n" \
 223         "  %y2 = add i32 %x, 1\n" \
 224         "  %y3 = invoke i32 @g() to label %bb1 unwind label %bb2\n" \
 225         "bb1:\n" \
 226         "  %y4 = add i32 %x, 1\n" \
 227         "  br label %bb4\n" \
 228         "bb2:\n" \
 229         "  %y5 = landingpad i32 personality i32 ()* @g\n" \
 230         "          cleanup\n" \
 231         "  br label %bb4\n" \
 232         "bb3:\n" \
 233         "  %y6 = add i32 %x, 1\n" \
 234         "  %y7 = add i32 %x, 1\n" \
 235         "  ret void\n" \
 236         "bb4:\n" \
 237         "  %y8 = phi i32 [0, %bb2], [%y4, %bb1]\n"
 238         "  %y9 = phi i32 [0, %bb2], [%y4, %bb1]\n"
 239         "  ret void\n" \
 240         "}\n";
 241       LLVMContext &C = getGlobalContext();
 242       SMDiagnostic Err;
 243       return parseAssemblyString(ModuleStrig, Err, C);
 244     }
 245
 246     TEST(DominatorTree, Unreachable) {
 247       DPass *P = new DPass();
 248       std::unique_ptr<Module> M = makeLLVMModule(P);
 249       legacy::PassManager Passes;
 250       Passes.add(P);
 251       Passes.run(*M);
 252     }
 253   }
 254 }
 255
 256 INITIALIZE_PASS_BEGIN(DPass, "dpass", "dpass", false, false)
 257 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 258 INITIALIZE_PASS_DEPENDENCY(PostDominatorTree)
 259 INITIALIZE_PASS_END(DPass, "dpass", "dpass", false, false)