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Diffstat (limited to 'llvm/unittests/IR/DomTreeUpdaterTest.cpp')
| -rw-r--r-- | llvm/unittests/IR/DomTreeUpdaterTest.cpp | 693 |
1 files changed, 693 insertions, 0 deletions
diff --git a/llvm/unittests/IR/DomTreeUpdaterTest.cpp b/llvm/unittests/IR/DomTreeUpdaterTest.cpp new file mode 100644 index 00000000000..a6d768920bc --- /dev/null +++ b/llvm/unittests/IR/DomTreeUpdaterTest.cpp @@ -0,0 +1,693 @@ +//==- llvm/unittests/IR/DomTreeUpdaterTest.cpp - DomTreeUpdater unit tests ===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "llvm/IR/DomTreeUpdater.h" +#include "llvm/Analysis/PostDominators.h" +#include "llvm/AsmParser/Parser.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/Dominators.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/LLVMContext.h" +#include "llvm/IR/Module.h" +#include "llvm/Support/SourceMgr.h" +#include "gtest/gtest.h" +#include <algorithm> + +using namespace llvm; + +static std::unique_ptr<Module> makeLLVMModule(LLVMContext &Context, + StringRef ModuleStr) { + SMDiagnostic Err; + std::unique_ptr<Module> M = parseAssemblyString(ModuleStr, Err, Context); + assert(M && "Bad LLVM IR?"); + return M; +} + +TEST(DomTreeUpdater, EagerUpdateBasicOperations) { + StringRef FuncName = "f"; + StringRef ModuleString = R"( + define i32 @f(i32 %i, i32 *%p) { + bb0: + store i32 %i, i32 *%p + switch i32 %i, label %bb1 [ + i32 1, label %bb2 + i32 2, label %bb3 + ] + bb1: + ret i32 1 + bb2: + ret i32 2 + bb3: + ret i32 3 + })"; + // Make the module. + LLVMContext Context; + std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString); + Function *F = M->getFunction(FuncName); + + // Make the DomTreeUpdater. + DominatorTree DT(*F); + PostDominatorTree PDT(*F); + DomTreeUpdater DTU(DT, PDT, DomTreeUpdater::UpdateStrategy::Eager); + + ASSERT_TRUE(DTU.hasDomTree()); + ASSERT_TRUE(DTU.hasPostDomTree()); + ASSERT_EQ(DTU.getUpdateStrategy(), DomTreeUpdater::UpdateStrategy::Eager); + ASSERT_TRUE(DTU.getDomTree().verify()); + ASSERT_TRUE(DTU.getPostDomTree().verify()); + ASSERT_FALSE(DTU.hasPendingUpdates()); + + Function::iterator FI = F->begin(); + BasicBlock *BB0 = &*FI++; + BasicBlock *BB1 = &*FI++; + BasicBlock *BB2 = &*FI++; + BasicBlock *BB3 = &*FI++; + SwitchInst *SI = dyn_cast<SwitchInst>(BB0->getTerminator()); + ASSERT_NE(SI, nullptr) << "Couldn't get SwitchInst."; + + ASSERT_FALSE(DTU.insertEdgeRelaxed(BB0, BB0)); + ASSERT_TRUE(DTU.deleteEdgeRelaxed(BB0, BB0)); + + // Delete edge bb0 -> bb3 and push the update twice to verify duplicate + // entries are discarded. + std::vector<DominatorTree::UpdateType> Updates; + Updates.reserve(4); + Updates.push_back({DominatorTree::Delete, BB0, BB3}); + Updates.push_back({DominatorTree::Delete, BB0, BB3}); + + // Invalid Insert: no edge bb1 -> bb2 after change to bb0. + Updates.push_back({DominatorTree::Insert, BB1, BB2}); + // Invalid Delete: edge exists bb0 -> bb1 after change to bb0. + Updates.push_back({DominatorTree::Delete, BB0, BB1}); + + // CFG Change: remove edge bb0 -> bb3. + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 3u); + BB3->removePredecessor(BB0); + for (auto i = SI->case_begin(), e = SI->case_end(); i != e; ++i) { + if (i->getCaseSuccessor() == BB3) { + SI->removeCase(i); + break; + } + } + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 2u); + // Deletion of a BasicBlock is an immediate event. We remove all uses to the + // contained Instructions and change the Terminator to "unreachable" when + // queued for deletion. + ASSERT_FALSE(isa<UnreachableInst>(BB3->getTerminator())); + EXPECT_FALSE(DTU.isBBPendingDeletion(BB3)); + DTU.applyUpdates(Updates, /*ForceRemoveDuplicates*/ true); + ASSERT_FALSE(DTU.hasPendingUpdates()); + + // Invalid Insert: no edge bb1 -> bb2 after change to bb0. + ASSERT_FALSE(DTU.insertEdgeRelaxed(BB1, BB2)); + // Invalid Delete: edge exists bb0 -> bb1 after change to bb0. + ASSERT_FALSE(DTU.deleteEdgeRelaxed(BB0, BB1)); + + // DTU working with Eager UpdateStrategy does not need to flush. + ASSERT_TRUE(DT.verify()); + ASSERT_TRUE(PDT.verify()); + + // Test callback utils. + ASSERT_EQ(BB3->getParent(), F); + DTU.callbackDeleteBB(BB3, + [&F](BasicBlock *BB) { ASSERT_NE(BB->getParent(), F); }); + + ASSERT_TRUE(DT.verify()); + ASSERT_TRUE(PDT.verify()); + ASSERT_FALSE(DTU.hasPendingUpdates()); + + // Unnecessary flush() test + DTU.flush(); + EXPECT_TRUE(DT.verify()); + EXPECT_TRUE(PDT.verify()); + + // Remove all case branch to BB2 to test Eager recalculation. + // Code section from llvm::ConstantFoldTerminator + for (auto i = SI->case_begin(), e = SI->case_end(); i != e;) { + if (i->getCaseSuccessor() == BB2) { + // Remove this entry. + BB2->removePredecessor(BB0); + i = SI->removeCase(i); + e = SI->case_end(); + } else + ++i; + } + ASSERT_FALSE(DT.verify()); + ASSERT_FALSE(PDT.verify()); + DTU.recalculate(*F); + ASSERT_TRUE(DT.verify()); + ASSERT_TRUE(PDT.verify()); +} + +TEST(DomTreeUpdater, EagerUpdateReplaceEntryBB) { + StringRef FuncName = "f"; + StringRef ModuleString = R"( + define i32 @f() { + bb0: + br label %bb1 + bb1: + ret i32 1 + } + )"; + // Make the module. + LLVMContext Context; + std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString); + Function *F = M->getFunction(FuncName); + + // Make the DTU. + DominatorTree DT(*F); + PostDominatorTree PDT(*F); + DomTreeUpdater DTU(DT, PDT, DomTreeUpdater::UpdateStrategy::Eager); + ASSERT_TRUE(DTU.hasDomTree()); + ASSERT_TRUE(DTU.hasPostDomTree()); + ASSERT_EQ(DTU.getUpdateStrategy(), DomTreeUpdater::UpdateStrategy::Eager); + ASSERT_TRUE(DT.verify()); + ASSERT_TRUE(PDT.verify()); + + Function::iterator FI = F->begin(); + BasicBlock *BB0 = &*FI++; + BasicBlock *BB1 = &*FI++; + + // Add a block as the new function entry BB. We also link it to BB0. + BasicBlock *NewEntry = + BasicBlock::Create(F->getContext(), "new_entry", F, BB0); + BranchInst::Create(BB0, NewEntry); + EXPECT_EQ(F->begin()->getName(), NewEntry->getName()); + EXPECT_TRUE(&F->getEntryBlock() == NewEntry); + + ASSERT_TRUE(DTU.insertEdgeRelaxed(NewEntry, BB0)); + + // Changing the Entry BB requires a full recalculation of DomTree. + DTU.recalculate(*F); + ASSERT_TRUE(DT.verify()); + ASSERT_TRUE(PDT.verify()); + + // CFG Change: remove new_edge -> bb0 and redirect to new_edge -> bb1. + EXPECT_EQ(NewEntry->getTerminator()->getNumSuccessors(), 1u); + NewEntry->getTerminator()->eraseFromParent(); + BranchInst::Create(BB1, NewEntry); + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 1u); + + // Update the DTU. At this point bb0 now has no predecessors but is still a + // Child of F. + DTU.applyUpdates({{DominatorTree::Delete, NewEntry, BB0}, + {DominatorTree::Insert, NewEntry, BB1}}); + ASSERT_TRUE(DT.verify()); + ASSERT_TRUE(PDT.verify()); + + // Now remove bb0 from F. + ASSERT_FALSE(isa<UnreachableInst>(BB0->getTerminator())); + EXPECT_FALSE(DTU.isBBPendingDeletion(BB0)); + DTU.deleteBB(BB0); + ASSERT_TRUE(DT.verify()); + ASSERT_TRUE(PDT.verify()); +} + +TEST(DomTreeUpdater, LazyUpdateDTBasicOperations) { + StringRef FuncName = "f"; + StringRef ModuleString = R"( + define i32 @f(i32 %i, i32 *%p) { + bb0: + store i32 %i, i32 *%p + switch i32 %i, label %bb1 [ + i32 0, label %bb2 + i32 1, label %bb2 + i32 2, label %bb3 + ] + bb1: + ret i32 1 + bb2: + ret i32 2 + bb3: + ret i32 3 + } + )"; + // Make the module. + LLVMContext Context; + std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString); + Function *F = M->getFunction(FuncName); + + // Make the DTU. + DominatorTree DT(*F); + DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Lazy); + ASSERT_TRUE(DTU.hasDomTree()); + ASSERT_FALSE(DTU.hasPostDomTree()); + ASSERT_EQ(DTU.getUpdateStrategy(), DomTreeUpdater::UpdateStrategy::Lazy); + ASSERT_TRUE(DTU.getDomTree().verify()); + + Function::iterator FI = F->begin(); + BasicBlock *BB0 = &*FI++; + BasicBlock *BB1 = &*FI++; + BasicBlock *BB2 = &*FI++; + BasicBlock *BB3 = &*FI++; + + // Test discards of self-domination update. + DTU.deleteEdge(BB0, BB0); + ASSERT_FALSE(DTU.hasPendingDomTreeUpdates()); + + // Delete edge bb0 -> bb3 and push the update twice to verify duplicate + // entries are discarded. + std::vector<DominatorTree::UpdateType> Updates; + Updates.reserve(4); + Updates.push_back({DominatorTree::Delete, BB0, BB3}); + Updates.push_back({DominatorTree::Delete, BB0, BB3}); + + // Invalid Insert: no edge bb1 -> bb2 after change to bb0. + Updates.push_back({DominatorTree::Insert, BB1, BB2}); + // Invalid Delete: edge exists bb0 -> bb1 after change to bb0. + Updates.push_back({DominatorTree::Delete, BB0, BB1}); + + // CFG Change: remove edge bb0 -> bb3 and one duplicate edge bb0 -> bb2. + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 4u); + BB0->getTerminator()->eraseFromParent(); + BranchInst::Create(BB1, BB2, ConstantInt::getTrue(F->getContext()), BB0); + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 2u); + + // Verify. Updates to DTU must be applied *after* all changes to the CFG + // (including block deletion). + DTU.applyUpdates(Updates); + ASSERT_TRUE(DTU.getDomTree().verify()); + + // Deletion of a BasicBlock is an immediate event. We remove all uses to the + // contained Instructions and change the Terminator to "unreachable" when + // queued for deletion. Its parent is still F until all the pending updates + // are applied to all trees held by the DomTreeUpdater (DomTree/PostDomTree). + // We don't defer this action because it can cause problems for other + // transforms or analysis as it's part of the actual CFG. We only defer + // updates to the DominatorTrees. This code will crash if it is placed before + // the BranchInst::Create() call above. After a deletion of a BasicBlock. Only + // an explicit flush event can trigger the flushing of deleteBBs. Because some + // passes using Lazy UpdateStrategy rely on this behavior. + + ASSERT_FALSE(isa<UnreachableInst>(BB3->getTerminator())); + EXPECT_FALSE(DTU.isBBPendingDeletion(BB3)); + EXPECT_FALSE(DTU.hasPendingDeletedBB()); + DTU.deleteBB(BB3); + EXPECT_TRUE(DTU.isBBPendingDeletion(BB3)); + EXPECT_TRUE(DTU.hasPendingDeletedBB()); + ASSERT_TRUE(isa<UnreachableInst>(BB3->getTerminator())); + EXPECT_EQ(BB3->getParent(), F); + DTU.recalculate(*F); + + EXPECT_FALSE(DTU.hasPendingDeletedBB()); +} + +TEST(DomTreeUpdater, LazyUpdateDTInheritedPreds) { + StringRef FuncName = "f"; + StringRef ModuleString = R"( + define i32 @f(i32 %i, i32 *%p) { + bb0: + store i32 %i, i32 *%p + switch i32 %i, label %bb1 [ + i32 2, label %bb2 + i32 3, label %bb3 + ] + bb1: + br label %bb3 + bb2: + br label %bb3 + bb3: + ret i32 3 + } + )"; + // Make the module. + LLVMContext Context; + std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString); + Function *F = M->getFunction(FuncName); + + // Make the DTU. + DominatorTree DT(*F); + DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Lazy); + ASSERT_TRUE(DTU.hasDomTree()); + ASSERT_FALSE(DTU.hasPostDomTree()); + ASSERT_EQ(DTU.getUpdateStrategy(), DomTreeUpdater::UpdateStrategy::Lazy); + ASSERT_TRUE(DTU.getDomTree().verify()); + + Function::iterator FI = F->begin(); + BasicBlock *BB0 = &*FI++; + BasicBlock *BB1 = &*FI++; + BasicBlock *BB2 = &*FI++; + BasicBlock *BB3 = &*FI++; + + // There are several CFG locations where we have: + // + // pred1..predN + // | | + // +> curr <+ converted into: pred1..predN curr + // | | | + // v +> succ <+ + // succ + // + // There is a specific shape of this we have to be careful of: + // + // pred1..predN + // || | + // |+> curr <+ converted into: pred1..predN curr + // | | | | + // | v +> succ <+ + // +-> succ + // + // While the final CFG form is functionally identical the updates to + // DTU are not. In the first case we must have DTU.insertEdge(Pred1, Succ) + // while in the latter case we must *NOT* have DTU.insertEdge(Pred1, Succ). + + // CFG Change: bb0 now only has bb0 -> bb1 and bb0 -> bb3. We are preparing to + // remove bb2. + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 3u); + BB0->getTerminator()->eraseFromParent(); + BranchInst::Create(BB1, BB3, ConstantInt::getTrue(F->getContext()), BB0); + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 2u); + + // Test callback utils. + std::vector<BasicBlock *> BasicBlocks; + BasicBlocks.push_back(BB1); + BasicBlocks.push_back(BB2); + auto Eraser = [&](BasicBlock *BB) { + BasicBlocks.erase( + std::remove_if(BasicBlocks.begin(), BasicBlocks.end(), + [&](const BasicBlock *i) { return i == BB; }), + BasicBlocks.end()); + }; + ASSERT_EQ(BasicBlocks.size(), static_cast<size_t>(2)); + // Remove bb2 from F. This has to happen before the call to applyUpdates() for + // DTU to detect there is no longer an edge between bb2 -> bb3. The deleteBB() + // method converts bb2's TI into "unreachable". + ASSERT_FALSE(isa<UnreachableInst>(BB2->getTerminator())); + EXPECT_FALSE(DTU.isBBPendingDeletion(BB2)); + DTU.callbackDeleteBB(BB2, Eraser); + EXPECT_TRUE(DTU.isBBPendingDeletion(BB2)); + ASSERT_TRUE(isa<UnreachableInst>(BB2->getTerminator())); + EXPECT_EQ(BB2->getParent(), F); + + // Queue up the DTU updates. + std::vector<DominatorTree::UpdateType> Updates; + Updates.reserve(4); + Updates.push_back({DominatorTree::Delete, BB0, BB2}); + Updates.push_back({DominatorTree::Delete, BB2, BB3}); + + // Handle the specific shape case next. + // CFG Change: bb0 now only branches to bb3. We are preparing to remove bb1. + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 2u); + BB0->getTerminator()->eraseFromParent(); + BranchInst::Create(BB3, BB0); + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 1u); + + // Remove bb1 from F. This has to happen before the call to applyUpdates() for + // DTU to detect there is no longer an edge between bb1 -> bb3. The deleteBB() + // method converts bb1's TI into "unreachable". + ASSERT_FALSE(isa<UnreachableInst>(BB1->getTerminator())); + EXPECT_FALSE(DTU.isBBPendingDeletion(BB1)); + DTU.callbackDeleteBB(BB1, Eraser); + EXPECT_TRUE(DTU.isBBPendingDeletion(BB1)); + ASSERT_TRUE(isa<UnreachableInst>(BB1->getTerminator())); + EXPECT_EQ(BB1->getParent(), F); + + // Update the DTU. In this case we don't call DTU.insertEdge(BB0, BB3) because + // the edge previously existed at the start of this test when DT was first + // created. + Updates.push_back({DominatorTree::Delete, BB0, BB1}); + Updates.push_back({DominatorTree::Delete, BB1, BB3}); + + // Verify everything. + DTU.applyUpdates(Updates); + ASSERT_EQ(BasicBlocks.size(), static_cast<size_t>(2)); + DTU.flush(); + ASSERT_EQ(BasicBlocks.size(), static_cast<size_t>(0)); + ASSERT_TRUE(DT.verify()); +} + +TEST(DomTreeUpdater, LazyUpdateBasicOperations) { + StringRef FuncName = "f"; + StringRef ModuleString = R"( + define i32 @f(i32 %i, i32 *%p) { + bb0: + store i32 %i, i32 *%p + switch i32 %i, label %bb1 [ + i32 0, label %bb2 + i32 1, label %bb2 + i32 2, label %bb3 + ] + bb1: + ret i32 1 + bb2: + ret i32 2 + bb3: + ret i32 3 + } + )"; + // Make the module. + LLVMContext Context; + std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString); + Function *F = M->getFunction(FuncName); + + // Make the DTU. + DominatorTree DT(*F); + PostDominatorTree PDT(*F); + DomTreeUpdater DTU(DT, PDT, DomTreeUpdater::UpdateStrategy::Lazy); + ASSERT_TRUE(DTU.hasDomTree()); + ASSERT_TRUE(DTU.hasPostDomTree()); + ASSERT_EQ(DTU.getUpdateStrategy(), DomTreeUpdater::UpdateStrategy::Lazy); + ASSERT_TRUE(DTU.getDomTree().verify()); + ASSERT_TRUE(DTU.getPostDomTree().verify()); + + Function::iterator FI = F->begin(); + BasicBlock *BB0 = &*FI++; + BasicBlock *BB1 = &*FI++; + BasicBlock *BB2 = &*FI++; + BasicBlock *BB3 = &*FI++; + // Test discards of self-domination update. + DTU.deleteEdge(BB0, BB0); + + // Delete edge bb0 -> bb3 and push the update twice to verify duplicate + // entries are discarded. + std::vector<DominatorTree::UpdateType> Updates; + Updates.reserve(4); + Updates.push_back({DominatorTree::Delete, BB0, BB3}); + Updates.push_back({DominatorTree::Delete, BB0, BB3}); + + // Unnecessary Insert: no edge bb1 -> bb2 after change to bb0. + Updates.push_back({DominatorTree::Insert, BB1, BB2}); + // Unnecessary Delete: edge exists bb0 -> bb1 after change to bb0. + Updates.push_back({DominatorTree::Delete, BB0, BB1}); + + // CFG Change: remove edge bb0 -> bb3 and one duplicate edge bb0 -> bb2. + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 4u); + BB0->getTerminator()->eraseFromParent(); + BranchInst::Create(BB1, BB2, ConstantInt::getTrue(F->getContext()), BB0); + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 2u); + + // Deletion of a BasicBlock is an immediate event. We remove all uses to the + // contained Instructions and change the Terminator to "unreachable" when + // queued for deletion. Its parent is still F until DTU.flushDomTree is + // called. We don't defer this action because it can cause problems for other + // transforms or analysis as it's part of the actual CFG. We only defer + // updates to the DominatorTree. This code will crash if it is placed before + // the BranchInst::Create() call above. + bool CallbackFlag = false; + ASSERT_FALSE(isa<UnreachableInst>(BB3->getTerminator())); + EXPECT_FALSE(DTU.isBBPendingDeletion(BB3)); + DTU.callbackDeleteBB(BB3, [&](BasicBlock *) { CallbackFlag = true; }); + EXPECT_TRUE(DTU.isBBPendingDeletion(BB3)); + ASSERT_TRUE(isa<UnreachableInst>(BB3->getTerminator())); + EXPECT_EQ(BB3->getParent(), F); + + // Verify. Updates to DTU must be applied *after* all changes to the CFG + // (including block deletion). + DTU.applyUpdates(Updates); + ASSERT_TRUE(DTU.getDomTree().verify()); + ASSERT_TRUE(DTU.hasPendingUpdates()); + ASSERT_TRUE(DTU.hasPendingPostDomTreeUpdates()); + ASSERT_FALSE(DTU.hasPendingDomTreeUpdates()); + ASSERT_TRUE(DTU.hasPendingDeletedBB()); + ASSERT_TRUE(DTU.getPostDomTree().verify()); + ASSERT_FALSE(DTU.hasPendingUpdates()); + ASSERT_FALSE(DTU.hasPendingPostDomTreeUpdates()); + ASSERT_FALSE(DTU.hasPendingDomTreeUpdates()); + ASSERT_FALSE(DTU.hasPendingDeletedBB()); + ASSERT_EQ(CallbackFlag, true); +} + +TEST(DomTreeUpdater, LazyUpdateReplaceEntryBB) { + StringRef FuncName = "f"; + StringRef ModuleString = R"( + define i32 @f() { + bb0: + br label %bb1 + bb1: + ret i32 1 + } + )"; + // Make the module. + LLVMContext Context; + std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString); + Function *F = M->getFunction(FuncName); + + // Make the DTU. + DominatorTree DT(*F); + PostDominatorTree PDT(*F); + DomTreeUpdater DTU(DT, PDT, DomTreeUpdater::UpdateStrategy::Lazy); + ASSERT_TRUE(DTU.hasDomTree()); + ASSERT_TRUE(DTU.hasPostDomTree()); + ASSERT_EQ(DTU.getUpdateStrategy(), DomTreeUpdater::UpdateStrategy::Lazy); + ASSERT_TRUE(DTU.getDomTree().verify()); + ASSERT_TRUE(DTU.getPostDomTree().verify()); + + Function::iterator FI = F->begin(); + BasicBlock *BB0 = &*FI++; + BasicBlock *BB1 = &*FI++; + + // Add a block as the new function entry BB. We also link it to BB0. + BasicBlock *NewEntry = + BasicBlock::Create(F->getContext(), "new_entry", F, BB0); + BranchInst::Create(BB0, NewEntry); + EXPECT_EQ(F->begin()->getName(), NewEntry->getName()); + EXPECT_TRUE(&F->getEntryBlock() == NewEntry); + + // Insert the new edge between new_entry -> bb0. Without this the + // recalculate() call below will not actually recalculate the DT as there + // are no changes pending and no blocks deleted. + DTU.insertEdge(NewEntry, BB0); + + // Changing the Entry BB requires a full recalculation. + DTU.recalculate(*F); + ASSERT_TRUE(DTU.getDomTree().verify()); + ASSERT_TRUE(DTU.getPostDomTree().verify()); + + // CFG Change: remove new_edge -> bb0 and redirect to new_edge -> bb1. + EXPECT_EQ(NewEntry->getTerminator()->getNumSuccessors(), 1u); + NewEntry->getTerminator()->eraseFromParent(); + BranchInst::Create(BB1, NewEntry); + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 1u); + + // Update the DTU. At this point bb0 now has no predecessors but is still a + // Child of F. + DTU.applyUpdates({{DominatorTree::Delete, NewEntry, BB0}, + {DominatorTree::Insert, NewEntry, BB1}}); + DTU.flush(); + ASSERT_TRUE(DT.verify()); + ASSERT_TRUE(PDT.verify()); + + // Now remove bb0 from F. + ASSERT_FALSE(isa<UnreachableInst>(BB0->getTerminator())); + EXPECT_FALSE(DTU.isBBPendingDeletion(BB0)); + DTU.deleteBB(BB0); + EXPECT_TRUE(DTU.isBBPendingDeletion(BB0)); + ASSERT_TRUE(isa<UnreachableInst>(BB0->getTerminator())); + EXPECT_EQ(BB0->getParent(), F); + + // Perform a full recalculation of the DTU. It is not necessary here but we + // do this to test the case when there are no pending DT updates but there are + // pending deleted BBs. + ASSERT_TRUE(DTU.hasPendingDeletedBB()); + DTU.recalculate(*F); + ASSERT_FALSE(DTU.hasPendingDeletedBB()); +} + +TEST(DomTreeUpdater, LazyUpdateStepTest) { + // This test focus on testing a DTU holding both trees applying multiple + // updates and DT/PDT not flushed together. + StringRef FuncName = "f"; + StringRef ModuleString = R"( + define i32 @f(i32 %i, i32 *%p) { + bb0: + store i32 %i, i32 *%p + switch i32 %i, label %bb1 [ + i32 0, label %bb1 + i32 1, label %bb2 + i32 2, label %bb3 + i32 3, label %bb1 + ] + bb1: + ret i32 1 + bb2: + ret i32 2 + bb3: + ret i32 3 + } + )"; + // Make the module. + LLVMContext Context; + std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString); + Function *F = M->getFunction(FuncName); + + // Make the DomTreeUpdater. + DominatorTree DT(*F); + PostDominatorTree PDT(*F); + DomTreeUpdater DTU(DT, PDT, DomTreeUpdater::UpdateStrategy::Lazy); + + ASSERT_TRUE(DTU.hasDomTree()); + ASSERT_TRUE(DTU.hasPostDomTree()); + ASSERT_EQ(DTU.getUpdateStrategy(), DomTreeUpdater::UpdateStrategy::Lazy); + ASSERT_TRUE(DTU.getDomTree().verify()); + ASSERT_TRUE(DTU.getPostDomTree().verify()); + ASSERT_FALSE(DTU.hasPendingUpdates()); + + Function::iterator FI = F->begin(); + BasicBlock *BB0 = &*FI++; + FI++; + BasicBlock *BB2 = &*FI++; + BasicBlock *BB3 = &*FI++; + SwitchInst *SI = dyn_cast<SwitchInst>(BB0->getTerminator()); + ASSERT_NE(SI, nullptr) << "Couldn't get SwitchInst."; + + // Delete edge bb0 -> bb3 and push the update twice to verify duplicate + // entries are discarded. + std::vector<DominatorTree::UpdateType> Updates; + Updates.reserve(1); + Updates.push_back({DominatorTree::Delete, BB0, BB3}); + + // CFG Change: remove edge bb0 -> bb3. + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 5u); + BB3->removePredecessor(BB0); + for (auto i = SI->case_begin(), e = SI->case_end(); i != e; ++i) { + if (i->getCaseIndex() == 2) { + SI->removeCase(i); + break; + } + } + EXPECT_EQ(BB0->getTerminator()->getNumSuccessors(), 4u); + // Deletion of a BasicBlock is an immediate event. We remove all uses to the + // contained Instructions and change the Terminator to "unreachable" when + // queued for deletion. + ASSERT_FALSE(isa<UnreachableInst>(BB3->getTerminator())); + EXPECT_FALSE(DTU.isBBPendingDeletion(BB3)); + DTU.applyUpdates(Updates); + + // Only flush DomTree. + ASSERT_TRUE(DTU.getDomTree().verify()); + ASSERT_TRUE(DTU.hasPendingPostDomTreeUpdates()); + ASSERT_FALSE(DTU.hasPendingDomTreeUpdates()); + + ASSERT_EQ(BB3->getParent(), F); + DTU.deleteBB(BB3); + + Updates.clear(); + + // Remove all case branch to BB2 to test Eager recalculation. + // Code section from llvm::ConstantFoldTerminator + for (auto i = SI->case_begin(), e = SI->case_end(); i != e;) { + if (i->getCaseSuccessor() == BB2) { + // Remove this entry. + BB2->removePredecessor(BB0); + i = SI->removeCase(i); + e = SI->case_end(); + Updates.push_back({DominatorTree::Delete, BB0, BB2}); + } else + ++i; + } + + DTU.applyUpdates(Updates); + // flush PostDomTree + ASSERT_TRUE(DTU.getPostDomTree().verify()); + ASSERT_FALSE(DTU.hasPendingPostDomTreeUpdates()); + ASSERT_TRUE(DTU.hasPendingDomTreeUpdates()); + // flush both trees + DTU.flush(); + ASSERT_TRUE(DT.verify()); +} |
