llvm/unittests/CodeGen/LexicalScopesTest.cpp

   1 //===----------- llvm/unittest/CodeGen/LexicalScopesTest.cpp --------------===//
   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/CodeGen/LexicalScopes.h"
  10 #include "llvm/CodeGen/MachineBasicBlock.h"
  11 #include "llvm/CodeGen/MachineFunction.h"
  12 #include "llvm/CodeGen/MachineInstr.h"
  13 #include "llvm/CodeGen/MachineMemOperand.h"
  14 #include "llvm/CodeGen/MachineModuleInfo.h"
  15 #include "llvm/CodeGen/TargetFrameLowering.h"
  16 #include "llvm/CodeGen/TargetInstrInfo.h"
  17 #include "llvm/CodeGen/TargetLowering.h"
  18 #include "llvm/CodeGen/TargetSubtargetInfo.h"
  19 #include "llvm/IR/DIBuilder.h"
  20 #include "llvm/IR/DebugInfoMetadata.h"
  21 #include "llvm/IR/IRBuilder.h"
  22 #include "llvm/IR/ModuleSlotTracker.h"
  23 #include "llvm/MC/MCAsmInfo.h"
  24 #include "llvm/MC/MCSymbol.h"
  25 #include "llvm/MC/TargetRegistry.h"
  26 #include "llvm/Support/TargetSelect.h"
  27 #include "llvm/Target/TargetMachine.h"
  28 #include "llvm/Target/TargetOptions.h"
  29
  30 #include "gtest/gtest.h"
  31
  32 using namespace llvm;
  33
  34 namespace {
  35 // Include helper functions to ease the manipulation of MachineFunctions
  36 #include "MFCommon.inc"
  37
  38 class LexicalScopesTest : public testing::Test {
  39 public:
  40   // Boilerplate,
  41   LLVMContext Ctx;
  42   Module Mod;
  43   std::unique_ptr<MachineFunction> MF;
  44   DICompileUnit *OurCU;
  45   DIFile *OurFile;
  46   DISubprogram *OurFunc;
  47   DILexicalBlock *OurBlock, *AnotherBlock;
  48   DISubprogram *ToInlineFunc;
  49   DILexicalBlock *ToInlineBlock;
  50   // DebugLocs that we'll used to create test environments.
  51   DebugLoc OutermostLoc, InBlockLoc, NotNestedBlockLoc, InlinedLoc;
  52
  53   // Test environment blocks -- these form a diamond control flow pattern,
  54   // MBB1 being the entry block, blocks two and three being the branches, and
  55   // block four joining the branches and being an exit block.
  56   MachineBasicBlock *MBB1, *MBB2, *MBB3, *MBB4;
  57
  58   // Some meaningless instructions -- the first is fully meaningless,
  59   // while the second is supposed to impersonate DBG_VALUEs through its
  60   // opcode.
  61   MCInstrDesc BeanInst;
  62   MCInstrDesc DbgValueInst;
  63
  64   LexicalScopesTest() : Ctx(), Mod("beehives", Ctx) {
  65     memset(&BeanInst, 0, sizeof(BeanInst));
  66     BeanInst.Opcode = 1;
  67     BeanInst.Size = 1;
  68
  69     memset(&DbgValueInst, 0, sizeof(DbgValueInst));
  70     DbgValueInst.Opcode = TargetOpcode::DBG_VALUE;
  71     DbgValueInst.Size = 1;
  72     DbgValueInst.Flags = 1U << MCID::Meta;
  73
  74     // Boilerplate that creates a MachineFunction and associated blocks.
  75     MF = createMachineFunction(Ctx, Mod);
  76     llvm::Function &F = const_cast<llvm::Function &>(MF->getFunction());
  77     auto BB1 = BasicBlock::Create(Ctx, "a", &F);
  78     auto BB2 = BasicBlock::Create(Ctx, "b", &F);
  79     auto BB3 = BasicBlock::Create(Ctx, "c", &F);
  80     auto BB4 = BasicBlock::Create(Ctx, "d", &F);
  81     IRBuilder<> IRB1(BB1), IRB2(BB2), IRB3(BB3), IRB4(BB4);
  82     IRB1.CreateBr(BB2);
  83     IRB2.CreateBr(BB3);
  84     IRB3.CreateBr(BB4);
  85     IRB4.CreateRetVoid();
  86     MBB1 = MF->CreateMachineBasicBlock(BB1);
  87     MF->insert(MF->end(), MBB1);
  88     MBB2 = MF->CreateMachineBasicBlock(BB2);
  89     MF->insert(MF->end(), MBB2);
  90     MBB3 = MF->CreateMachineBasicBlock(BB3);
  91     MF->insert(MF->end(), MBB3);
  92     MBB4 = MF->CreateMachineBasicBlock(BB4);
  93     MF->insert(MF->end(), MBB4);
  94     MBB1->addSuccessor(MBB2);
  95     MBB1->addSuccessor(MBB3);
  96     MBB2->addSuccessor(MBB4);
  97     MBB3->addSuccessor(MBB4);
  98
  99     // Create metadata: CU, subprogram, some blocks and an inline function
 100     // scope.
 101     DIBuilder DIB(Mod);
 102     OurFile = DIB.createFile("xyzzy.c", "/cave");
 103     OurCU =
 104         DIB.createCompileUnit(dwarf::DW_LANG_C99, OurFile, "nou", false, "", 0);
 105     auto OurSubT = DIB.createSubroutineType(DIB.getOrCreateTypeArray(None));
 106     OurFunc =
 107         DIB.createFunction(OurCU, "bees", "", OurFile, 1, OurSubT, 1,
 108                            DINode::FlagZero, DISubprogram::SPFlagDefinition);
 109     F.setSubprogram(OurFunc);
 110     OurBlock = DIB.createLexicalBlock(OurFunc, OurFile, 2, 3);
 111     AnotherBlock = DIB.createLexicalBlock(OurFunc, OurFile, 2, 6);
 112     ToInlineFunc =
 113         DIB.createFunction(OurFile, "shoes", "", OurFile, 10, OurSubT, 10,
 114                            DINode::FlagZero, DISubprogram::SPFlagDefinition);
 115
 116     // Make some nested scopes.
 117     OutermostLoc = DILocation::get(Ctx, 3, 1, OurFunc);
 118     InBlockLoc = DILocation::get(Ctx, 4, 1, OurBlock);
 119     InlinedLoc = DILocation::get(Ctx, 10, 1, ToInlineFunc, InBlockLoc.get());
 120
 121     // Make a scope that isn't nested within the others.
 122     NotNestedBlockLoc = DILocation::get(Ctx, 4, 1, AnotherBlock);
 123
 124     DIB.finalize();
 125   }
 126 };
 127
 128 // Fill blocks with dummy instructions, test some base lexical scope
 129 // functionaliy.
 130 TEST_F(LexicalScopesTest, FlatLayout) {
 131   BuildMI(*MBB1, MBB1->end(), OutermostLoc, BeanInst);
 132   BuildMI(*MBB2, MBB2->end(), OutermostLoc, BeanInst);
 133   BuildMI(*MBB3, MBB3->end(), OutermostLoc, BeanInst);
 134   BuildMI(*MBB4, MBB4->end(), OutermostLoc, BeanInst);
 135
 136   LexicalScopes LS;
 137   EXPECT_TRUE(LS.empty());
 138   LS.reset();
 139   EXPECT_EQ(LS.getCurrentFunctionScope(), nullptr);
 140
 141   LS.initialize(*MF);
 142   EXPECT_FALSE(LS.empty());
 143   LexicalScope *FuncScope = LS.getCurrentFunctionScope();
 144   EXPECT_EQ(FuncScope->getParent(), nullptr);
 145   EXPECT_EQ(FuncScope->getDesc(), OurFunc);
 146   EXPECT_EQ(FuncScope->getInlinedAt(), nullptr);
 147   EXPECT_EQ(FuncScope->getScopeNode(), OurFunc);
 148   EXPECT_FALSE(FuncScope->isAbstractScope());
 149   EXPECT_EQ(FuncScope->getChildren().size(), 0u);
 150
 151   // There should be one range, covering the whole function. Test that it
 152   // points at the correct instructions.
 153   auto &Ranges = FuncScope->getRanges();
 154   ASSERT_EQ(Ranges.size(), 1u);
 155   EXPECT_EQ(Ranges.front().first, &*MF->begin()->begin());
 156   auto BBIt = MF->end();
 157   BBIt = std::prev(BBIt);
 158   EXPECT_EQ(Ranges.front().second, &*BBIt->begin());
 159
 160   EXPECT_TRUE(FuncScope->dominates(FuncScope));
 161   SmallPtrSet<const MachineBasicBlock *, 4> MBBVec;
 162   LS.getMachineBasicBlocks(OutermostLoc.get(), MBBVec);
 163
 164   EXPECT_EQ(MBBVec.size(), 4u);
 165   // All the blocks should be in that set; the outermost loc should dominate
 166   // them; and no other scope should.
 167   for (auto &MBB : *MF) {
 168     EXPECT_EQ(MBBVec.count(&MBB), 1u);
 169     EXPECT_TRUE(LS.dominates(OutermostLoc.get(), &MBB));
 170     EXPECT_FALSE(LS.dominates(InBlockLoc.get(), &MBB));
 171     EXPECT_FALSE(LS.dominates(InlinedLoc.get(), &MBB));
 172   }
 173 }
 174
 175 // Examine relationship between two nested scopes inside the function, the
 176 // outer function and the lexical block within it.
 177 TEST_F(LexicalScopesTest, BlockScopes) {
 178   BuildMI(*MBB1, MBB1->end(), InBlockLoc, BeanInst);
 179   BuildMI(*MBB2, MBB2->end(), InBlockLoc, BeanInst);
 180   BuildMI(*MBB3, MBB3->end(), InBlockLoc, BeanInst);
 181   BuildMI(*MBB4, MBB4->end(), InBlockLoc, BeanInst);
 182
 183   LexicalScopes LS;
 184   LS.initialize(*MF);
 185   LexicalScope *FuncScope = LS.getCurrentFunctionScope();
 186   EXPECT_EQ(FuncScope->getDesc(), OurFunc);
 187   auto &Children = FuncScope->getChildren();
 188   ASSERT_EQ(Children.size(), 1u);
 189   auto *BlockScope = Children[0];
 190   EXPECT_EQ(LS.findLexicalScope(InBlockLoc.get()), BlockScope);
 191   EXPECT_EQ(BlockScope->getDesc(), InBlockLoc->getScope());
 192   EXPECT_FALSE(BlockScope->isAbstractScope());
 193
 194   EXPECT_TRUE(FuncScope->dominates(BlockScope));
 195   EXPECT_FALSE(BlockScope->dominates(FuncScope));
 196   EXPECT_EQ(FuncScope->getParent(), nullptr);
 197   EXPECT_EQ(BlockScope->getParent(), FuncScope);
 198
 199   SmallPtrSet<const MachineBasicBlock *, 4> MBBVec;
 200   LS.getMachineBasicBlocks(OutermostLoc.get(), MBBVec);
 201
 202   EXPECT_EQ(MBBVec.size(), 4u);
 203   for (auto &MBB : *MF) {
 204     EXPECT_EQ(MBBVec.count(&MBB), 1u);
 205     EXPECT_TRUE(LS.dominates(OutermostLoc.get(), &MBB));
 206     EXPECT_TRUE(LS.dominates(InBlockLoc.get(), &MBB));
 207     EXPECT_FALSE(LS.dominates(InlinedLoc.get(), &MBB));
 208   }
 209 }
 210
 211 // Test inlined scopes functionality and relationship with the outer scopes.
 212 TEST_F(LexicalScopesTest, InlinedScopes) {
 213   BuildMI(*MBB1, MBB1->end(), InlinedLoc, BeanInst);
 214   BuildMI(*MBB2, MBB2->end(), InlinedLoc, BeanInst);
 215   BuildMI(*MBB3, MBB3->end(), InlinedLoc, BeanInst);
 216   BuildMI(*MBB4, MBB4->end(), InlinedLoc, BeanInst);
 217
 218   LexicalScopes LS;
 219   LS.initialize(*MF);
 220   LexicalScope *FuncScope = LS.getCurrentFunctionScope();
 221   auto &Children = FuncScope->getChildren();
 222   ASSERT_EQ(Children.size(), 1u);
 223   auto *BlockScope = Children[0];
 224   auto &BlockChildren = BlockScope->getChildren();
 225   ASSERT_EQ(BlockChildren.size(), 1u);
 226   auto *InlinedScope = BlockChildren[0];
 227
 228   EXPECT_FALSE(InlinedScope->isAbstractScope());
 229   EXPECT_EQ(InlinedScope->getInlinedAt(), InlinedLoc.getInlinedAt());
 230   EXPECT_EQ(InlinedScope->getDesc(), InlinedLoc.getScope());
 231   EXPECT_EQ(InlinedScope->getChildren().size(), 0u);
 232
 233   EXPECT_EQ(FuncScope->getParent(), nullptr);
 234   EXPECT_EQ(BlockScope->getParent(), FuncScope);
 235   EXPECT_EQ(InlinedScope->getParent(), BlockScope);
 236
 237   const auto &AbstractScopes = LS.getAbstractScopesList();
 238   ASSERT_EQ(AbstractScopes.size(), 1u);
 239   const auto &AbstractScope = *AbstractScopes[0];
 240   EXPECT_TRUE(AbstractScope.isAbstractScope());
 241   EXPECT_EQ(AbstractScope.getDesc(), InlinedLoc.getScope());
 242   EXPECT_EQ(AbstractScope.getInlinedAt(), nullptr);
 243   EXPECT_EQ(AbstractScope.getParent(), nullptr);
 244 }
 245
 246 // Test behaviour in a function that has empty DebugLocs.
 247 TEST_F(LexicalScopesTest, FuncWithEmptyGap) {
 248   BuildMI(*MBB1, MBB1->end(), OutermostLoc, BeanInst);
 249   BuildMI(*MBB2, MBB2->end(), DebugLoc(), BeanInst);
 250   BuildMI(*MBB3, MBB3->end(), DebugLoc(), BeanInst);
 251   BuildMI(*MBB4, MBB4->end(), OutermostLoc, BeanInst);
 252
 253   LexicalScopes LS;
 254   LS.initialize(*MF);
 255   LexicalScope *FuncScope = LS.getCurrentFunctionScope();
 256
 257   // A gap in a range that contains no other location, is not actually a
 258   // gap as far as lexical scopes are concerned.
 259   auto &Ranges = FuncScope->getRanges();
 260   ASSERT_EQ(Ranges.size(), 1u);
 261   EXPECT_EQ(Ranges[0].first, &*MF->begin()->begin());
 262   auto BBIt = MF->end();
 263   BBIt = std::prev(BBIt);
 264   EXPECT_EQ(Ranges[0].second, &*BBIt->begin());
 265 }
 266
 267 // Now a function with intervening not-in-scope instructions.
 268 TEST_F(LexicalScopesTest, FuncWithRealGap) {
 269   MachineInstr *FirstI = BuildMI(*MBB1, MBB1->end(), InBlockLoc, BeanInst);
 270   BuildMI(*MBB2, MBB2->end(), OutermostLoc, BeanInst);
 271   BuildMI(*MBB3, MBB3->end(), OutermostLoc, BeanInst);
 272   MachineInstr *LastI = BuildMI(*MBB4, MBB4->end(), InBlockLoc, BeanInst);
 273
 274   LexicalScopes LS;
 275   LS.initialize(*MF);
 276   LexicalScope *BlockScope = LS.findLexicalScope(InBlockLoc.get());
 277   ASSERT_NE(BlockScope, nullptr);
 278
 279   // Within the block scope, there's a gap between the first and last
 280   // block / instruction, where it's only the outermost scope.
 281   auto &Ranges = BlockScope->getRanges();
 282   ASSERT_EQ(Ranges.size(), 2u);
 283   EXPECT_EQ(Ranges[0].first, FirstI);
 284   EXPECT_EQ(Ranges[0].second, FirstI);
 285   EXPECT_EQ(Ranges[1].first, LastI);
 286   EXPECT_EQ(Ranges[1].second, LastI);
 287
 288   // The outer function scope should cover the whole function, including
 289   // blocks the lexicalblock covers.
 290   LexicalScope *FuncScope = LS.getCurrentFunctionScope();
 291   auto &FuncRanges = FuncScope->getRanges();
 292   ASSERT_EQ(FuncRanges.size(), 1u);
 293   EXPECT_NE(FuncRanges[0].first, FuncRanges[0].second);
 294   EXPECT_EQ(FuncRanges[0].first, FirstI);
 295   EXPECT_EQ(FuncRanges[0].second, LastI);
 296 }
 297
 298 // Examine the relationship between two scopes that don't nest (are siblings).
 299 TEST_F(LexicalScopesTest, NotNested) {
 300   MachineInstr *FirstI = BuildMI(*MBB1, MBB1->end(), InBlockLoc, BeanInst);
 301   MachineInstr *SecondI =
 302       BuildMI(*MBB2, MBB2->end(), NotNestedBlockLoc, BeanInst);
 303   MachineInstr *ThirdI =
 304       BuildMI(*MBB3, MBB3->end(), NotNestedBlockLoc, BeanInst);
 305   MachineInstr *FourthI = BuildMI(*MBB4, MBB4->end(), InBlockLoc, BeanInst);
 306
 307   LexicalScopes LS;
 308   LS.initialize(*MF);
 309   LexicalScope *FuncScope = LS.getCurrentFunctionScope();
 310   LexicalScope *BlockScope = LS.findLexicalScope(InBlockLoc.get());
 311   LexicalScope *OtherBlockScope = LS.findLexicalScope(NotNestedBlockLoc.get());
 312   ASSERT_NE(FuncScope, nullptr);
 313   ASSERT_NE(BlockScope, nullptr);
 314   ASSERT_NE(OtherBlockScope, nullptr);
 315
 316   // The function should cover everything; the two blocks are distinct and
 317   // should not.
 318   auto &FuncRanges = FuncScope->getRanges();
 319   ASSERT_EQ(FuncRanges.size(), 1u);
 320   EXPECT_EQ(FuncRanges[0].first, FirstI);
 321   EXPECT_EQ(FuncRanges[0].second, FourthI);
 322
 323   // Two ranges, start and end instructions.
 324   auto &BlockRanges = BlockScope->getRanges();
 325   ASSERT_EQ(BlockRanges.size(), 2u);
 326   EXPECT_EQ(BlockRanges[0].first, FirstI);
 327   EXPECT_EQ(BlockRanges[0].second, FirstI);
 328   EXPECT_EQ(BlockRanges[1].first, FourthI);
 329   EXPECT_EQ(BlockRanges[1].second, FourthI);
 330
 331   // One inner range, covering the two inner blocks.
 332   auto &OtherBlockRanges = OtherBlockScope->getRanges();
 333   ASSERT_EQ(OtherBlockRanges.size(), 1u);
 334   EXPECT_EQ(OtherBlockRanges[0].first, SecondI);
 335   EXPECT_EQ(OtherBlockRanges[0].second, ThirdI);
 336 }
 337
 338 // Test the scope-specific and block-specific dominates methods.
 339 TEST_F(LexicalScopesTest, TestDominates) {
 340   BuildMI(*MBB1, MBB1->end(), InBlockLoc, BeanInst);
 341   BuildMI(*MBB2, MBB2->end(), NotNestedBlockLoc, BeanInst);
 342   BuildMI(*MBB3, MBB3->end(), NotNestedBlockLoc, BeanInst);
 343   BuildMI(*MBB4, MBB4->end(), InBlockLoc, BeanInst);
 344
 345   LexicalScopes LS;
 346   LS.initialize(*MF);
 347   LexicalScope *FuncScope = LS.getCurrentFunctionScope();
 348   LexicalScope *BlockScope = LS.findLexicalScope(InBlockLoc.get());
 349   LexicalScope *OtherBlockScope = LS.findLexicalScope(NotNestedBlockLoc.get());
 350   ASSERT_NE(FuncScope, nullptr);
 351   ASSERT_NE(BlockScope, nullptr);
 352   ASSERT_NE(OtherBlockScope, nullptr);
 353
 354   EXPECT_TRUE(FuncScope->dominates(BlockScope));
 355   EXPECT_TRUE(FuncScope->dominates(OtherBlockScope));
 356   EXPECT_FALSE(BlockScope->dominates(FuncScope));
 357   EXPECT_FALSE(BlockScope->dominates(OtherBlockScope));
 358   EXPECT_FALSE(OtherBlockScope->dominates(FuncScope));
 359   EXPECT_FALSE(OtherBlockScope->dominates(BlockScope));
 360
 361   // Outermost scope dominates everything, as all insts are within it.
 362   EXPECT_TRUE(LS.dominates(OutermostLoc.get(), MBB1));
 363   EXPECT_TRUE(LS.dominates(OutermostLoc.get(), MBB2));
 364   EXPECT_TRUE(LS.dominates(OutermostLoc.get(), MBB3));
 365   EXPECT_TRUE(LS.dominates(OutermostLoc.get(), MBB4));
 366
 367   // One inner block dominates the outer pair of blocks,
 368   EXPECT_TRUE(LS.dominates(InBlockLoc.get(), MBB1));
 369   EXPECT_FALSE(LS.dominates(InBlockLoc.get(), MBB2));
 370   EXPECT_FALSE(LS.dominates(InBlockLoc.get(), MBB3));
 371   EXPECT_TRUE(LS.dominates(InBlockLoc.get(), MBB4));
 372
 373   // While the other dominates the inner two blocks.
 374   EXPECT_FALSE(LS.dominates(NotNestedBlockLoc.get(), MBB1));
 375   EXPECT_TRUE(LS.dominates(NotNestedBlockLoc.get(), MBB2));
 376   EXPECT_TRUE(LS.dominates(NotNestedBlockLoc.get(), MBB3));
 377   EXPECT_FALSE(LS.dominates(NotNestedBlockLoc.get(), MBB4));
 378 }
 379
 380 // Test getMachineBasicBlocks returns all dominated blocks.
 381 TEST_F(LexicalScopesTest, TestGetBlocks) {
 382   BuildMI(*MBB1, MBB1->end(), InBlockLoc, BeanInst);
 383   BuildMI(*MBB2, MBB2->end(), NotNestedBlockLoc, BeanInst);
 384   BuildMI(*MBB3, MBB3->end(), NotNestedBlockLoc, BeanInst);
 385   BuildMI(*MBB4, MBB4->end(), InBlockLoc, BeanInst);
 386
 387   LexicalScopes LS;
 388   LS.initialize(*MF);
 389   LexicalScope *FuncScope = LS.getCurrentFunctionScope();
 390   LexicalScope *BlockScope = LS.findLexicalScope(InBlockLoc.get());
 391   LexicalScope *OtherBlockScope = LS.findLexicalScope(NotNestedBlockLoc.get());
 392   ASSERT_NE(FuncScope, nullptr);
 393   ASSERT_NE(BlockScope, nullptr);
 394   ASSERT_NE(OtherBlockScope, nullptr);
 395
 396   SmallPtrSet<const MachineBasicBlock *, 4> OutermostBlocks, InBlockBlocks,
 397       NotNestedBlockBlocks;
 398   LS.getMachineBasicBlocks(OutermostLoc.get(), OutermostBlocks);
 399   LS.getMachineBasicBlocks(InBlockLoc.get(), InBlockBlocks);
 400   LS.getMachineBasicBlocks(NotNestedBlockLoc.get(), NotNestedBlockBlocks);
 401
 402   EXPECT_EQ(OutermostBlocks.count(MBB1), 1u);
 403   EXPECT_EQ(OutermostBlocks.count(MBB2), 1u);
 404   EXPECT_EQ(OutermostBlocks.count(MBB3), 1u);
 405   EXPECT_EQ(OutermostBlocks.count(MBB4), 1u);
 406
 407   EXPECT_EQ(InBlockBlocks.count(MBB1), 1u);
 408   EXPECT_EQ(InBlockBlocks.count(MBB2), 0u);
 409   EXPECT_EQ(InBlockBlocks.count(MBB3), 0u);
 410   EXPECT_EQ(InBlockBlocks.count(MBB4), 1u);
 411
 412   EXPECT_EQ(NotNestedBlockBlocks.count(MBB1), 0u);
 413   EXPECT_EQ(NotNestedBlockBlocks.count(MBB2), 1u);
 414   EXPECT_EQ(NotNestedBlockBlocks.count(MBB3), 1u);
 415   EXPECT_EQ(NotNestedBlockBlocks.count(MBB4), 0u);
 416 }
 417
 418 TEST_F(LexicalScopesTest, TestMetaInst) {
 419   // Instruction Layout looks like this, where 'F' means funcscope, and
 420   // 'B' blockscope:
 421   // bb1:
 422   //   F: bean
 423   //   B: bean
 424   // bb2:
 425   //   F: bean
 426   //   B: DBG_VALUE
 427   // bb3:
 428   //   F: bean
 429   //   B: DBG_VALUE
 430   // bb4:
 431   //   F: bean
 432   //   B: bean
 433   // The block / 'B' should only dominate bb1 and bb4. DBG_VALUE is a meta
 434   // instruction, and shouldn't contribute to scopes.
 435   BuildMI(*MBB1, MBB1->end(), OutermostLoc, BeanInst);
 436   BuildMI(*MBB1, MBB1->end(), InBlockLoc, BeanInst);
 437   BuildMI(*MBB2, MBB2->end(), OutermostLoc, BeanInst);
 438   BuildMI(*MBB2, MBB2->end(), InBlockLoc, DbgValueInst);
 439   BuildMI(*MBB3, MBB3->end(), OutermostLoc, BeanInst);
 440   BuildMI(*MBB3, MBB3->end(), InBlockLoc, DbgValueInst);
 441   BuildMI(*MBB4, MBB4->end(), OutermostLoc, BeanInst);
 442   BuildMI(*MBB4, MBB4->end(), InBlockLoc, BeanInst);
 443
 444   LexicalScopes LS;
 445   LS.initialize(*MF);
 446   LexicalScope *FuncScope = LS.getCurrentFunctionScope();
 447   LexicalScope *BlockScope = LS.findLexicalScope(InBlockLoc.get());
 448   ASSERT_NE(FuncScope, nullptr);
 449   ASSERT_NE(BlockScope, nullptr);
 450
 451   EXPECT_TRUE(LS.dominates(OutermostLoc.get(), MBB1));
 452   EXPECT_TRUE(LS.dominates(OutermostLoc.get(), MBB2));
 453   EXPECT_TRUE(LS.dominates(OutermostLoc.get(), MBB3));
 454   EXPECT_TRUE(LS.dominates(OutermostLoc.get(), MBB4));
 455   EXPECT_TRUE(LS.dominates(InBlockLoc.get(), MBB1));
 456   EXPECT_FALSE(LS.dominates(InBlockLoc.get(), MBB2));
 457   EXPECT_FALSE(LS.dominates(InBlockLoc.get(), MBB3));
 458   EXPECT_TRUE(LS.dominates(InBlockLoc.get(), MBB4));
 459 }
 460
 461 } // anonymous namespace