compiler/dex/mir_graph_test.cc - platform/art - Gitiles

 /*
  * Copyright (C) 2014 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "mir_graph.h"
 #include "gtest/gtest.h"

 namespace art {

 class TopologicalSortOrderTest : public testing::Test {
  protected:
   struct BBDef {
     static constexpr size_t kMaxSuccessors = 4;
     static constexpr size_t kMaxPredecessors = 4;

     BBType type;
     size_t num_successors;
     BasicBlockId successors[kMaxPredecessors];
     size_t num_predecessors;
     BasicBlockId predecessors[kMaxPredecessors];
   };

 #define DEF_SUCC0() \
     0u, { }
 #define DEF_SUCC1(s1) \
     1u, { s1 }
 #define DEF_SUCC2(s1, s2) \
     2u, { s1, s2 }
 #define DEF_SUCC3(s1, s2, s3) \
     3u, { s1, s2, s3 }
 #define DEF_SUCC4(s1, s2, s3, s4) \
     4u, { s1, s2, s3, s4 }
 #define DEF_PRED0() \
     0u, { }
 #define DEF_PRED1(p1) \
     1u, { p1 }
 #define DEF_PRED2(p1, p2) \
     2u, { p1, p2 }
 #define DEF_PRED3(p1, p2, p3) \
     3u, { p1, p2, p3 }
 #define DEF_PRED4(p1, p2, p3, p4) \
     4u, { p1, p2, p3, p4 }
 #define DEF_BB(type, succ, pred) \
     { type, succ, pred }

   void DoPrepareBasicBlocks(const BBDef* defs, size_t count) {
     cu_.mir_graph->block_id_map_.clear();
     cu_.mir_graph->block_list_.clear();
     ASSERT_LT(3u, count);  // null, entry, exit and at least one bytecode block.
     ASSERT_EQ(kNullBlock, defs[0].type);
     ASSERT_EQ(kEntryBlock, defs[1].type);
     ASSERT_EQ(kExitBlock, defs[2].type);
     for (size_t i = 0u; i != count; ++i) {
       const BBDef* def = &defs[i];
       BasicBlock* bb = cu_.mir_graph->CreateNewBB(def->type);
       if (def->num_successors <= 2) {
         bb->successor_block_list_type = kNotUsed;
         bb->fall_through = (def->num_successors >= 1) ? def->successors[0] : 0u;
         bb->taken = (def->num_successors >= 2) ? def->successors[1] : 0u;
       } else {
         bb->successor_block_list_type = kPackedSwitch;
         bb->fall_through = 0u;
         bb->taken = 0u;
         bb->successor_blocks.reserve(def->num_successors);
         for (size_t j = 0u; j != def->num_successors; ++j) {
           SuccessorBlockInfo* successor_block_info =
               static_cast<SuccessorBlockInfo*>(cu_.arena.Alloc(sizeof(SuccessorBlockInfo),
                                                                kArenaAllocSuccessor));
           successor_block_info->block = j;
           successor_block_info->key = 0u;  // Not used by class init check elimination.
           bb->successor_blocks.push_back(successor_block_info);
         }
       }
       bb->predecessors.assign(def->predecessors, def->predecessors + def->num_predecessors);
       if (def->type == kDalvikByteCode || def->type == kEntryBlock || def->type == kExitBlock) {
         bb->data_flow_info = static_cast<BasicBlockDataFlow*>(
             cu_.arena.Alloc(sizeof(BasicBlockDataFlow), kArenaAllocDFInfo));
       }
     }
     cu_.mir_graph->num_blocks_ = count;
     ASSERT_EQ(count, cu_.mir_graph->block_list_.size());
     cu_.mir_graph->entry_block_ = cu_.mir_graph->block_list_[1];
     ASSERT_EQ(kEntryBlock, cu_.mir_graph->entry_block_->block_type);
     cu_.mir_graph->exit_block_ = cu_.mir_graph->block_list_[2];
     ASSERT_EQ(kExitBlock, cu_.mir_graph->exit_block_->block_type);

     DexFile::CodeItem* code_item = static_cast<DexFile::CodeItem*>(cu_.arena.Alloc(sizeof(DexFile::CodeItem),
                                                                                    kArenaAllocMisc));
     cu_.mir_graph->current_code_item_ = code_item;
   }

   template <size_t count>
   void PrepareBasicBlocks(const BBDef (&defs)[count]) {
     DoPrepareBasicBlocks(defs, count);
   }

   void ComputeTopologicalSortOrder() {
     cu_.mir_graph->SSATransformationStart();
     cu_.mir_graph->ComputeDFSOrders();
     cu_.mir_graph->ComputeDominators();
     cu_.mir_graph->ComputeTopologicalSortOrder();
     cu_.mir_graph->SSATransformationEnd();
     ASSERT_FALSE(cu_.mir_graph->topological_order_.empty());
     ASSERT_FALSE(cu_.mir_graph->topological_order_loop_ends_.empty());
     ASSERT_FALSE(cu_.mir_graph->topological_order_indexes_.empty());
     ASSERT_EQ(cu_.mir_graph->GetNumBlocks(), cu_.mir_graph->topological_order_indexes_.size());
     for (size_t i = 0, size = cu_.mir_graph->GetTopologicalSortOrder().size(); i != size; ++i) {
       ASSERT_LT(cu_.mir_graph->topological_order_[i], cu_.mir_graph->GetNumBlocks());
       BasicBlockId id = cu_.mir_graph->topological_order_[i];
       EXPECT_EQ(i, cu_.mir_graph->topological_order_indexes_[id]);
     }
   }

   void DoCheckOrder(const BasicBlockId* ids, size_t count) {
     ASSERT_EQ(count, cu_.mir_graph->GetTopologicalSortOrder().size());
     for (size_t i = 0; i != count; ++i) {
       EXPECT_EQ(ids[i], cu_.mir_graph->GetTopologicalSortOrder()[i]) << i;
     }
   }

   template <size_t count>
   void CheckOrder(const BasicBlockId (&ids)[count]) {
     DoCheckOrder(ids, count);
   }

   void DoCheckLoopEnds(const uint16_t* ends, size_t count) {
     for (size_t i = 0; i != count; ++i) {
       ASSERT_LT(i, cu_.mir_graph->GetTopologicalSortOrderLoopEnds().size());
       EXPECT_EQ(ends[i], cu_.mir_graph->GetTopologicalSortOrderLoopEnds()[i]) << i;
     }
   }

   template <size_t count>
   void CheckLoopEnds(const uint16_t (&ends)[count]) {
     DoCheckLoopEnds(ends, count);
   }

   TopologicalSortOrderTest()
       : pool_(),
         cu_(&pool_) {
     cu_.mir_graph.reset(new MIRGraph(&cu_, &cu_.arena));
   }

   ArenaPool pool_;
   CompilationUnit cu_;
 };

 TEST_F(TopologicalSortOrderTest, DoWhile) {
   const BBDef bbs[] = {
       DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
       DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
       DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(5)),
       DEF_BB(kDalvikByteCode, DEF_SUCC1(4), DEF_PRED1(1)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 4), DEF_PRED2(3, 4)),  // "taken" loops to self.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(4)),
   };
   const BasicBlockId expected_order[] = {
       1, 3, 4, 5, 2
   };
   const uint16_t loop_ends[] = {
       0, 0, 3, 0, 0
   };

   PrepareBasicBlocks(bbs);
   ComputeTopologicalSortOrder();
   CheckOrder(expected_order);
   CheckLoopEnds(loop_ends);
 }

 TEST_F(TopologicalSortOrderTest, While) {
   const BBDef bbs[] = {
       DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
       DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
       DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(5)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 5), DEF_PRED2(1, 4)),
       DEF_BB(kDalvikByteCode, DEF_SUCC1(3), DEF_PRED1(3)),     // Loops to 3.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
   };
   const BasicBlockId expected_order[] = {
       1, 3, 4, 5, 2
   };
   const uint16_t loop_ends[] = {
       0, 3, 0, 0, 0
   };

   PrepareBasicBlocks(bbs);
   ComputeTopologicalSortOrder();
   CheckOrder(expected_order);
   CheckLoopEnds(loop_ends);
 }

 TEST_F(TopologicalSortOrderTest, WhileWithTwoBackEdges) {
   const BBDef bbs[] = {
       DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
       DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
       DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(6)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 6), DEF_PRED3(1, 4, 5)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 3), DEF_PRED1(3)),     // Loops to 3.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(3), DEF_PRED1(4)),        // Loops to 3.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
   };
   const BasicBlockId expected_order[] = {
       1, 3, 4, 5, 6, 2
   };
   const uint16_t loop_ends[] = {
       0, 4, 0, 0, 0, 0
   };

   PrepareBasicBlocks(bbs);
   ComputeTopologicalSortOrder();
   CheckOrder(expected_order);
   CheckLoopEnds(loop_ends);
 }

 TEST_F(TopologicalSortOrderTest, NestedLoop) {
   const BBDef bbs[] = {
       DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
       DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
       DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(7)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 7), DEF_PRED2(1, 6)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 6), DEF_PRED2(3, 5)),
       DEF_BB(kDalvikByteCode, DEF_SUCC1(4), DEF_PRED1(4)),            // Loops to 4.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(3), DEF_PRED1(4)),            // Loops to 3.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
   };
   const BasicBlockId expected_order[] = {
       1, 3, 4, 5, 6, 7, 2
   };
   const uint16_t loop_ends[] = {
       0, 5, 4, 0, 0, 0, 0
   };

   PrepareBasicBlocks(bbs);
   ComputeTopologicalSortOrder();
   CheckOrder(expected_order);
   CheckLoopEnds(loop_ends);
 }

 TEST_F(TopologicalSortOrderTest, NestedLoopHeadLoops) {
   const BBDef bbs[] = {
       DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
       DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
       DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(6)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 6), DEF_PRED2(1, 4)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 3), DEF_PRED2(3, 5)),      // Nested head, loops to 3.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(4), DEF_PRED1(4)),            // Loops to 4.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
   };
   const BasicBlockId expected_order[] = {
       1, 3, 4, 5, 6, 2
   };
   const uint16_t loop_ends[] = {
       0, 4, 4, 0, 0, 0
   };

   PrepareBasicBlocks(bbs);
   ComputeTopologicalSortOrder();
   CheckOrder(expected_order);
   CheckLoopEnds(loop_ends);
 }

 TEST_F(TopologicalSortOrderTest, NestedLoopSameBackBranchBlock) {
   const BBDef bbs[] = {
       DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
       DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
       DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(6)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 6), DEF_PRED2(1, 5)),
       DEF_BB(kDalvikByteCode, DEF_SUCC1(5), DEF_PRED2(3, 5)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 3), DEF_PRED1(4)),         // Loops to 4 and 3.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
   };
   const BasicBlockId expected_order[] = {
       1, 3, 4, 5, 6, 2
   };
   const uint16_t loop_ends[] = {
       0, 4, 4, 0, 0, 0
   };

   PrepareBasicBlocks(bbs);
   ComputeTopologicalSortOrder();
   CheckOrder(expected_order);
   CheckLoopEnds(loop_ends);
 }

 TEST_F(TopologicalSortOrderTest, TwoReorderedInnerLoops) {
   // This is a simplified version of real code graph where the branch from 8 to 5 must prevent
   // the block 5 from being considered a loop head before processing the loop 7-8.
   const BBDef bbs[] = {
       DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
       DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
       DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(9)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 9), DEF_PRED2(1, 5)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 7), DEF_PRED1(3)),         // Branch over loop in 5.
       DEF_BB(kDalvikByteCode, DEF_SUCC2(6, 3), DEF_PRED3(4, 6, 8)),   // Loops to 4; inner loop.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(5), DEF_PRED1(5)),            // Loops to 5.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(8), DEF_PRED2(4, 8)),         // Loop head.
       DEF_BB(kDalvikByteCode, DEF_SUCC2(7, 5), DEF_PRED1(7)),         // Loops to 7; branches to 5.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
   };
   const BasicBlockId expected_order[] = {
       1, 3, 4, 7, 8, 5, 6, 9, 2
   };
   const uint16_t loop_ends[] = {
       0, 7, 0, 5, 0, 7, 0, 0, 0
   };

   PrepareBasicBlocks(bbs);
   ComputeTopologicalSortOrder();
   CheckOrder(expected_order);
   CheckLoopEnds(loop_ends);
 }

 TEST_F(TopologicalSortOrderTest, NestedLoopWithBackEdgeAfterOuterLoopBackEdge) {
   // This is a simplified version of real code graph. The back-edge from 7 to the inner
   // loop head 4 comes after the back-edge from 6 to the outer loop head 3. To make this
   // appear a bit more complex, there's also a back-edge from 5 to 4.
   const BBDef bbs[] = {
       DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
       DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
       DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(7)),
       DEF_BB(kDalvikByteCode, DEF_SUCC1(4), DEF_PRED2(1, 6)),         // Outer loop head.
       DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 6), DEF_PRED3(3, 5, 7)),   // Inner loop head.
       DEF_BB(kDalvikByteCode, DEF_SUCC1(4), DEF_PRED1(4)),            // Loops to inner loop head 4.
       DEF_BB(kDalvikByteCode, DEF_SUCC2(7, 3), DEF_PRED1(4)),         // Loops to outer loop head 3.
       DEF_BB(kDalvikByteCode, DEF_SUCC2(2, 4), DEF_PRED1(6)),         // Loops to inner loop head 4.
   };
   const BasicBlockId expected_order[] = {
       // NOTE: The 5 goes before 6 only because 5 is a "fall-through" from 4 while 6 is "taken".
       1, 3, 4, 5, 6, 7, 2
   };
   const uint16_t loop_ends[] = {
       0, 6, 6, 0, 0, 0, 0
   };

   PrepareBasicBlocks(bbs);
   ComputeTopologicalSortOrder();
   CheckOrder(expected_order);
   CheckLoopEnds(loop_ends);
 }

 TEST_F(TopologicalSortOrderTest, LoopWithTwoEntryPoints) {
   const BBDef bbs[] = {
       DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
       DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
       DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(7)),
       DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 4), DEF_PRED1(1)),
       DEF_BB(kDalvikByteCode, DEF_SUCC1(5), DEF_PRED2(3, 6)),  // Fall-back block is chosen as
       DEF_BB(kDalvikByteCode, DEF_SUCC1(6), DEF_PRED2(3, 4)),  // the earlier from these two.
       DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 7), DEF_PRED1(5)),
       DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(6)),
   };
   const BasicBlockId expected_order[] = {
       1, 3, 4, 5, 6, 7, 2
   };
   const uint16_t loop_ends[] = {
       0, 0, 5, 0, 0, 0, 0
   };

   PrepareBasicBlocks(bbs);
   ComputeTopologicalSortOrder();
   CheckOrder(expected_order);
   CheckLoopEnds(loop_ends);
 }

 }  // namespace art
	/*
	* Copyright (C) 2014 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "mir_graph.h"
	#include "gtest/gtest.h"

	namespace art {

	class TopologicalSortOrderTest : public testing::Test {
	protected:
	struct BBDef {
	static constexpr size_t kMaxSuccessors = 4;
	static constexpr size_t kMaxPredecessors = 4;

	BBType type;
	size_t num_successors;
	BasicBlockId successors[kMaxPredecessors];
	size_t num_predecessors;
	BasicBlockId predecessors[kMaxPredecessors];
	};

	#define DEF_SUCC0() \
	0u, { }
	#define DEF_SUCC1(s1) \
	1u, { s1 }
	#define DEF_SUCC2(s1, s2) \
	2u, { s1, s2 }
	#define DEF_SUCC3(s1, s2, s3) \
	3u, { s1, s2, s3 }
	#define DEF_SUCC4(s1, s2, s3, s4) \
	4u, { s1, s2, s3, s4 }
	#define DEF_PRED0() \
	0u, { }
	#define DEF_PRED1(p1) \
	1u, { p1 }
	#define DEF_PRED2(p1, p2) \
	2u, { p1, p2 }
	#define DEF_PRED3(p1, p2, p3) \
	3u, { p1, p2, p3 }
	#define DEF_PRED4(p1, p2, p3, p4) \
	4u, { p1, p2, p3, p4 }
	#define DEF_BB(type, succ, pred) \
	{ type, succ, pred }

	void DoPrepareBasicBlocks(const BBDef* defs, size_t count) {
	cu_.mir_graph->block_id_map_.clear();
	cu_.mir_graph->block_list_.clear();
	ASSERT_LT(3u, count); // null, entry, exit and at least one bytecode block.
	ASSERT_EQ(kNullBlock, defs[0].type);
	ASSERT_EQ(kEntryBlock, defs[1].type);
	ASSERT_EQ(kExitBlock, defs[2].type);
	for (size_t i = 0u; i != count; ++i) {
	const BBDef* def = &defs[i];
	BasicBlock* bb = cu_.mir_graph->CreateNewBB(def->type);
	if (def->num_successors <= 2) {
	bb->successor_block_list_type = kNotUsed;
	bb->fall_through = (def->num_successors >= 1) ? def->successors[0] : 0u;
	bb->taken = (def->num_successors >= 2) ? def->successors[1] : 0u;
	} else {
	bb->successor_block_list_type = kPackedSwitch;
	bb->fall_through = 0u;
	bb->taken = 0u;
	bb->successor_blocks.reserve(def->num_successors);
	for (size_t j = 0u; j != def->num_successors; ++j) {
	SuccessorBlockInfo* successor_block_info =
	static_cast<SuccessorBlockInfo*>(cu_.arena.Alloc(sizeof(SuccessorBlockInfo),
	kArenaAllocSuccessor));
	successor_block_info->block = j;
	successor_block_info->key = 0u; // Not used by class init check elimination.
	bb->successor_blocks.push_back(successor_block_info);
	}
	}
	bb->predecessors.assign(def->predecessors, def->predecessors + def->num_predecessors);
	if (def->type == kDalvikByteCode \|\| def->type == kEntryBlock \|\| def->type == kExitBlock) {
	bb->data_flow_info = static_cast<BasicBlockDataFlow*>(
	cu_.arena.Alloc(sizeof(BasicBlockDataFlow), kArenaAllocDFInfo));
	}
	}
	cu_.mir_graph->num_blocks_ = count;
	ASSERT_EQ(count, cu_.mir_graph->block_list_.size());
	cu_.mir_graph->entry_block_ = cu_.mir_graph->block_list_[1];
	ASSERT_EQ(kEntryBlock, cu_.mir_graph->entry_block_->block_type);
	cu_.mir_graph->exit_block_ = cu_.mir_graph->block_list_[2];
	ASSERT_EQ(kExitBlock, cu_.mir_graph->exit_block_->block_type);

	DexFile::CodeItem* code_item = static_cast<DexFile::CodeItem*>(cu_.arena.Alloc(sizeof(DexFile::CodeItem),
	kArenaAllocMisc));
	cu_.mir_graph->current_code_item_ = code_item;
	}

	template <size_t count>
	void PrepareBasicBlocks(const BBDef (&defs)[count]) {
	DoPrepareBasicBlocks(defs, count);
	}

	void ComputeTopologicalSortOrder() {
	cu_.mir_graph->SSATransformationStart();
	cu_.mir_graph->ComputeDFSOrders();
	cu_.mir_graph->ComputeDominators();
	cu_.mir_graph->ComputeTopologicalSortOrder();
	cu_.mir_graph->SSATransformationEnd();
	ASSERT_FALSE(cu_.mir_graph->topological_order_.empty());
	ASSERT_FALSE(cu_.mir_graph->topological_order_loop_ends_.empty());
	ASSERT_FALSE(cu_.mir_graph->topological_order_indexes_.empty());
	ASSERT_EQ(cu_.mir_graph->GetNumBlocks(), cu_.mir_graph->topological_order_indexes_.size());
	for (size_t i = 0, size = cu_.mir_graph->GetTopologicalSortOrder().size(); i != size; ++i) {
	ASSERT_LT(cu_.mir_graph->topological_order_[i], cu_.mir_graph->GetNumBlocks());
	BasicBlockId id = cu_.mir_graph->topological_order_[i];
	EXPECT_EQ(i, cu_.mir_graph->topological_order_indexes_[id]);
	}
	}

	void DoCheckOrder(const BasicBlockId* ids, size_t count) {
	ASSERT_EQ(count, cu_.mir_graph->GetTopologicalSortOrder().size());
	for (size_t i = 0; i != count; ++i) {
	EXPECT_EQ(ids[i], cu_.mir_graph->GetTopologicalSortOrder()[i]) << i;
	}
	}

	template <size_t count>
	void CheckOrder(const BasicBlockId (&ids)[count]) {
	DoCheckOrder(ids, count);
	}

	void DoCheckLoopEnds(const uint16_t* ends, size_t count) {
	for (size_t i = 0; i != count; ++i) {
	ASSERT_LT(i, cu_.mir_graph->GetTopologicalSortOrderLoopEnds().size());
	EXPECT_EQ(ends[i], cu_.mir_graph->GetTopologicalSortOrderLoopEnds()[i]) << i;
	}
	}

	template <size_t count>
	void CheckLoopEnds(const uint16_t (&ends)[count]) {
	DoCheckLoopEnds(ends, count);
	}

	TopologicalSortOrderTest()
	: pool_(),
	cu_(&pool_) {
	cu_.mir_graph.reset(new MIRGraph(&cu_, &cu_.arena));
	}

	ArenaPool pool_;
	CompilationUnit cu_;
	};

	TEST_F(TopologicalSortOrderTest, DoWhile) {
	const BBDef bbs[] = {
	DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
	DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
	DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(5)),
	DEF_BB(kDalvikByteCode, DEF_SUCC1(4), DEF_PRED1(1)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 4), DEF_PRED2(3, 4)), // "taken" loops to self.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(4)),
	};
	const BasicBlockId expected_order[] = {
	1, 3, 4, 5, 2
	};
	const uint16_t loop_ends[] = {
	0, 0, 3, 0, 0
	};

	PrepareBasicBlocks(bbs);
	ComputeTopologicalSortOrder();
	CheckOrder(expected_order);
	CheckLoopEnds(loop_ends);
	}

	TEST_F(TopologicalSortOrderTest, While) {
	const BBDef bbs[] = {
	DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
	DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
	DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(5)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 5), DEF_PRED2(1, 4)),
	DEF_BB(kDalvikByteCode, DEF_SUCC1(3), DEF_PRED1(3)), // Loops to 3.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
	};
	const BasicBlockId expected_order[] = {
	1, 3, 4, 5, 2
	};
	const uint16_t loop_ends[] = {
	0, 3, 0, 0, 0
	};

	PrepareBasicBlocks(bbs);
	ComputeTopologicalSortOrder();
	CheckOrder(expected_order);
	CheckLoopEnds(loop_ends);
	}

	TEST_F(TopologicalSortOrderTest, WhileWithTwoBackEdges) {
	const BBDef bbs[] = {
	DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
	DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
	DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(6)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 6), DEF_PRED3(1, 4, 5)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 3), DEF_PRED1(3)), // Loops to 3.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(3), DEF_PRED1(4)), // Loops to 3.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
	};
	const BasicBlockId expected_order[] = {
	1, 3, 4, 5, 6, 2
	};
	const uint16_t loop_ends[] = {
	0, 4, 0, 0, 0, 0
	};

	PrepareBasicBlocks(bbs);
	ComputeTopologicalSortOrder();
	CheckOrder(expected_order);
	CheckLoopEnds(loop_ends);
	}

	TEST_F(TopologicalSortOrderTest, NestedLoop) {
	const BBDef bbs[] = {
	DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
	DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
	DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(7)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 7), DEF_PRED2(1, 6)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 6), DEF_PRED2(3, 5)),
	DEF_BB(kDalvikByteCode, DEF_SUCC1(4), DEF_PRED1(4)), // Loops to 4.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(3), DEF_PRED1(4)), // Loops to 3.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
	};
	const BasicBlockId expected_order[] = {
	1, 3, 4, 5, 6, 7, 2
	};
	const uint16_t loop_ends[] = {
	0, 5, 4, 0, 0, 0, 0
	};

	PrepareBasicBlocks(bbs);
	ComputeTopologicalSortOrder();
	CheckOrder(expected_order);
	CheckLoopEnds(loop_ends);
	}

	TEST_F(TopologicalSortOrderTest, NestedLoopHeadLoops) {
	const BBDef bbs[] = {
	DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
	DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
	DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(6)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 6), DEF_PRED2(1, 4)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 3), DEF_PRED2(3, 5)), // Nested head, loops to 3.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(4), DEF_PRED1(4)), // Loops to 4.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
	};
	const BasicBlockId expected_order[] = {
	1, 3, 4, 5, 6, 2
	};
	const uint16_t loop_ends[] = {
	0, 4, 4, 0, 0, 0
	};

	PrepareBasicBlocks(bbs);
	ComputeTopologicalSortOrder();
	CheckOrder(expected_order);
	CheckLoopEnds(loop_ends);
	}

	TEST_F(TopologicalSortOrderTest, NestedLoopSameBackBranchBlock) {
	const BBDef bbs[] = {
	DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
	DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
	DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(6)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 6), DEF_PRED2(1, 5)),
	DEF_BB(kDalvikByteCode, DEF_SUCC1(5), DEF_PRED2(3, 5)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 3), DEF_PRED1(4)), // Loops to 4 and 3.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
	};
	const BasicBlockId expected_order[] = {
	1, 3, 4, 5, 6, 2
	};
	const uint16_t loop_ends[] = {
	0, 4, 4, 0, 0, 0
	};

	PrepareBasicBlocks(bbs);
	ComputeTopologicalSortOrder();
	CheckOrder(expected_order);
	CheckLoopEnds(loop_ends);
	}

	TEST_F(TopologicalSortOrderTest, TwoReorderedInnerLoops) {
	// This is a simplified version of real code graph where the branch from 8 to 5 must prevent
	// the block 5 from being considered a loop head before processing the loop 7-8.
	const BBDef bbs[] = {
	DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
	DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
	DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(9)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 9), DEF_PRED2(1, 5)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 7), DEF_PRED1(3)), // Branch over loop in 5.
	DEF_BB(kDalvikByteCode, DEF_SUCC2(6, 3), DEF_PRED3(4, 6, 8)), // Loops to 4; inner loop.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(5), DEF_PRED1(5)), // Loops to 5.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(8), DEF_PRED2(4, 8)), // Loop head.
	DEF_BB(kDalvikByteCode, DEF_SUCC2(7, 5), DEF_PRED1(7)), // Loops to 7; branches to 5.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(3)),
	};
	const BasicBlockId expected_order[] = {
	1, 3, 4, 7, 8, 5, 6, 9, 2
	};
	const uint16_t loop_ends[] = {
	0, 7, 0, 5, 0, 7, 0, 0, 0
	};

	PrepareBasicBlocks(bbs);
	ComputeTopologicalSortOrder();
	CheckOrder(expected_order);
	CheckLoopEnds(loop_ends);
	}

	TEST_F(TopologicalSortOrderTest, NestedLoopWithBackEdgeAfterOuterLoopBackEdge) {
	// This is a simplified version of real code graph. The back-edge from 7 to the inner
	// loop head 4 comes after the back-edge from 6 to the outer loop head 3. To make this
	// appear a bit more complex, there's also a back-edge from 5 to 4.
	const BBDef bbs[] = {
	DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
	DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
	DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(7)),
	DEF_BB(kDalvikByteCode, DEF_SUCC1(4), DEF_PRED2(1, 6)), // Outer loop head.
	DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 6), DEF_PRED3(3, 5, 7)), // Inner loop head.
	DEF_BB(kDalvikByteCode, DEF_SUCC1(4), DEF_PRED1(4)), // Loops to inner loop head 4.
	DEF_BB(kDalvikByteCode, DEF_SUCC2(7, 3), DEF_PRED1(4)), // Loops to outer loop head 3.
	DEF_BB(kDalvikByteCode, DEF_SUCC2(2, 4), DEF_PRED1(6)), // Loops to inner loop head 4.
	};
	const BasicBlockId expected_order[] = {
	// NOTE: The 5 goes before 6 only because 5 is a "fall-through" from 4 while 6 is "taken".
	1, 3, 4, 5, 6, 7, 2
	};
	const uint16_t loop_ends[] = {
	0, 6, 6, 0, 0, 0, 0
	};

	PrepareBasicBlocks(bbs);
	ComputeTopologicalSortOrder();
	CheckOrder(expected_order);
	CheckLoopEnds(loop_ends);
	}

	TEST_F(TopologicalSortOrderTest, LoopWithTwoEntryPoints) {
	const BBDef bbs[] = {
	DEF_BB(kNullBlock, DEF_SUCC0(), DEF_PRED0()),
	DEF_BB(kEntryBlock, DEF_SUCC1(3), DEF_PRED0()),
	DEF_BB(kExitBlock, DEF_SUCC0(), DEF_PRED1(7)),
	DEF_BB(kDalvikByteCode, DEF_SUCC2(5, 4), DEF_PRED1(1)),
	DEF_BB(kDalvikByteCode, DEF_SUCC1(5), DEF_PRED2(3, 6)), // Fall-back block is chosen as
	DEF_BB(kDalvikByteCode, DEF_SUCC1(6), DEF_PRED2(3, 4)), // the earlier from these two.
	DEF_BB(kDalvikByteCode, DEF_SUCC2(4, 7), DEF_PRED1(5)),
	DEF_BB(kDalvikByteCode, DEF_SUCC1(2), DEF_PRED1(6)),
	};
	const BasicBlockId expected_order[] = {
	1, 3, 4, 5, 6, 7, 2
	};
	const uint16_t loop_ends[] = {
	0, 0, 5, 0, 0, 0, 0
	};

	PrepareBasicBlocks(bbs);
	ComputeTopologicalSortOrder();
	CheckOrder(expected_order);
	CheckLoopEnds(loop_ends);
	}

	} // namespace art