compiler/optimizing/dead_code_elimination_test.cc - platform/art - Git at Google

 /*
  * 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 "arch/x86/instruction_set_features_x86.h"
 #include "code_generator_x86.h"
 #include "dead_code_elimination.h"
 #include "driver/compiler_options.h"
 #include "graph_checker.h"
 #include "optimizing_unit_test.h"
 #include "pretty_printer.h"

 #include "gtest/gtest.h"

 namespace art {

 static void TestCode(const uint16_t* data,
                      const std::string& expected_before,
                      const std::string& expected_after) {
   ArenaPool pool;
   ArenaAllocator allocator(&pool);
   HGraph* graph = CreateCFG(&allocator, data);
   ASSERT_NE(graph, nullptr);

   graph->TryBuildingSsa();

   StringPrettyPrinter printer_before(graph);
   printer_before.VisitInsertionOrder();
   std::string actual_before = printer_before.str();
   ASSERT_EQ(actual_before, expected_before);

   std::unique_ptr<const X86InstructionSetFeatures> features_x86(
       X86InstructionSetFeatures::FromCppDefines());
   x86::CodeGeneratorX86 codegenX86(graph, *features_x86.get(), CompilerOptions());
   HDeadCodeElimination(graph).Run();
   SSAChecker ssa_checker(&allocator, graph);
   ssa_checker.Run();
   ASSERT_TRUE(ssa_checker.IsValid());

   StringPrettyPrinter printer_after(graph);
   printer_after.VisitInsertionOrder();
   std::string actual_after = printer_after.str();
   ASSERT_EQ(actual_after, expected_after);
 }


 /**
  * Small three-register program.
  *
  *                              16-bit
  *                              offset
  *                              ------
  *     v1 <- 1                  0.      const/4 v1, #+1
  *     v0 <- 0                  1.      const/4 v0, #+0
  *     if v1 >= 0 goto L1       2.      if-gez v1, +3
  *     v0 <- v1                 4.      move v0, v1
  * L1: v2 <- v0 + v1            5.      add-int v2, v0, v1
  *     return-void              7.      return
  */
 TEST(DeadCodeElimination, AdditionAndConditionalJump) {
   const uint16_t data[] = THREE_REGISTERS_CODE_ITEM(
     Instruction::CONST_4 | 1 << 8 | 1 << 12,
     Instruction::CONST_4 | 0 << 8 | 0 << 12,
     Instruction::IF_GEZ | 1 << 8, 3,
     Instruction::MOVE | 0 << 8 | 1 << 12,
     Instruction::ADD_INT | 2 << 8, 0 | 1 << 8,
     Instruction::RETURN_VOID);

   std::string expected_before =
     "BasicBlock 0, succ: 1\n"
     "  3: IntConstant [15, 22, 8]\n"
     "  5: IntConstant [22, 8]\n"
     "  19: SuspendCheck\n"
     "  20: Goto 1\n"
     "BasicBlock 1, pred: 0, succ: 5, 2\n"
     "  8: GreaterThanOrEqual(3, 5) [9]\n"
     "  9: If(8)\n"
     "BasicBlock 2, pred: 1, succ: 3\n"
     "  12: Goto 3\n"
     "BasicBlock 3, pred: 2, 5, succ: 4\n"
     "  22: Phi(3, 5) [15]\n"
     "  15: Add(22, 3)\n"
     "  17: ReturnVoid\n"
     "BasicBlock 4, pred: 3\n"
     "  18: Exit\n"
     "BasicBlock 5, pred: 1, succ: 3\n"
     "  21: Goto 3\n";

   // Expected difference after dead code elimination.
   diff_t expected_diff = {
     { "  3: IntConstant [15, 22, 8]\n", "  3: IntConstant [22, 8]\n" },
     { "  22: Phi(3, 5) [15]\n",         "  22: Phi(3, 5)\n" },
     { "  15: Add(22, 3)\n",             removed }
   };
   std::string expected_after = Patch(expected_before, expected_diff);

   TestCode(data, expected_before, expected_after);
 }

 /**
  * Three-register program with jumps leading to the creation of many
  * blocks.
  *
  * The intent of this test is to ensure that all dead instructions are
  * actually pruned at compile-time, thanks to the (backward)
  * post-order traversal of the the dominator tree.
  *
  *                              16-bit
  *                              offset
  *                              ------
  *     v0 <- 0                   0.     const/4 v0, #+0
  *     v1 <- 1                   1.     const/4 v1, #+1
  *     v2 <- v0 + v1             2.     add-int v2, v0, v1
  *     goto L2                   4.     goto +4
  * L1: v1 <- v0 + 3              5.     add-int/lit16 v1, v0, #+3
  *     goto L3                   7.     goto +4
  * L2: v0 <- v2 + 2              8.     add-int/lit16 v0, v2, #+2
  *     goto L1                  10.     goto +(-5)
  * L3: v2 <- v1 + 4             11.     add-int/lit16 v2, v1, #+4
  *     return                   13.     return-void
  */
 TEST(DeadCodeElimination, AdditionsAndInconditionalJumps) {
   const uint16_t data[] = THREE_REGISTERS_CODE_ITEM(
     Instruction::CONST_4 | 0 << 8 | 0 << 12,
     Instruction::CONST_4 | 1 << 8 | 1 << 12,
     Instruction::ADD_INT | 2 << 8, 0 | 1 << 8,
     Instruction::GOTO | 4 << 8,
     Instruction::ADD_INT_LIT16 | 1 << 8 | 0 << 12, 3,
     Instruction::GOTO | 4 << 8,
     Instruction::ADD_INT_LIT16 | 0 << 8 | 2 << 12, 2,
     static_cast<uint16_t>(Instruction::GOTO | -5 << 8),
     Instruction::ADD_INT_LIT16 | 2 << 8 | 1 << 12, 4,
     Instruction::RETURN_VOID);

   std::string expected_before =
     "BasicBlock 0, succ: 1\n"
     "  3: IntConstant [9]\n"
     "  5: IntConstant [9]\n"
     "  13: IntConstant [14]\n"
     "  18: IntConstant [19]\n"
     "  24: IntConstant [25]\n"
     "  29: SuspendCheck\n"
     "  30: Goto 1\n"
     "BasicBlock 1, pred: 0, succ: 3\n"
     "  9: Add(3, 5) [19]\n"
     "  11: Goto 3\n"
     "BasicBlock 2, pred: 3, succ: 4\n"
     "  14: Add(19, 13) [25]\n"
     "  16: Goto 4\n"
     "BasicBlock 3, pred: 1, succ: 2\n"
     "  19: Add(9, 18) [14]\n"
     "  21: SuspendCheck\n"
     "  22: Goto 2\n"
     "BasicBlock 4, pred: 2, succ: 5\n"
     "  25: Add(14, 24)\n"
     "  27: ReturnVoid\n"
     "BasicBlock 5, pred: 4\n"
     "  28: Exit\n";

   // Expected difference after dead code elimination.
   diff_t expected_diff = {
     { "  13: IntConstant [14]\n", removed },
     { "  24: IntConstant [25]\n", removed },
     { "  14: Add(19, 13) [25]\n", removed },
     // The SuspendCheck instruction following this Add instruction
     // inserts the latter in an environment, thus making it "used" and
     // therefore non removable.  It ensues that some other Add and
     // IntConstant instructions cannot be removed, as they are direct
     // or indirect inputs of the initial Add instruction.
     { "  19: Add(9, 18) [14]\n",  "  19: Add(9, 18) []\n" },
     { "  25: Add(14, 24)\n",      removed },
   };
   std::string expected_after = Patch(expected_before, expected_diff);

   TestCode(data, expected_before, expected_after);
 }

 }  // 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 "arch/x86/instruction_set_features_x86.h"
	#include "code_generator_x86.h"
	#include "dead_code_elimination.h"
	#include "driver/compiler_options.h"
	#include "graph_checker.h"
	#include "optimizing_unit_test.h"
	#include "pretty_printer.h"

	#include "gtest/gtest.h"

	namespace art {

	static void TestCode(const uint16_t* data,
	const std::string& expected_before,
	const std::string& expected_after) {
	ArenaPool pool;
	ArenaAllocator allocator(&pool);
	HGraph* graph = CreateCFG(&allocator, data);
	ASSERT_NE(graph, nullptr);

	graph->TryBuildingSsa();

	StringPrettyPrinter printer_before(graph);
	printer_before.VisitInsertionOrder();
	std::string actual_before = printer_before.str();
	ASSERT_EQ(actual_before, expected_before);

	std::unique_ptr<const X86InstructionSetFeatures> features_x86(
	X86InstructionSetFeatures::FromCppDefines());
	x86::CodeGeneratorX86 codegenX86(graph, *features_x86.get(), CompilerOptions());
	HDeadCodeElimination(graph).Run();
	SSAChecker ssa_checker(&allocator, graph);
	ssa_checker.Run();
	ASSERT_TRUE(ssa_checker.IsValid());

	StringPrettyPrinter printer_after(graph);
	printer_after.VisitInsertionOrder();
	std::string actual_after = printer_after.str();
	ASSERT_EQ(actual_after, expected_after);
	}


	/**
	* Small three-register program.
	*
	* 16-bit
	* offset
	* ------
	* v1 <- 1 0. const/4 v1, #+1
	* v0 <- 0 1. const/4 v0, #+0
	* if v1 >= 0 goto L1 2. if-gez v1, +3
	* v0 <- v1 4. move v0, v1
	* L1: v2 <- v0 + v1 5. add-int v2, v0, v1
	* return-void 7. return
	*/
	TEST(DeadCodeElimination, AdditionAndConditionalJump) {
	const uint16_t data[] = THREE_REGISTERS_CODE_ITEM(
	Instruction::CONST_4 \| 1 << 8 \| 1 << 12,
	Instruction::CONST_4 \| 0 << 8 \| 0 << 12,
	Instruction::IF_GEZ \| 1 << 8, 3,
	Instruction::MOVE \| 0 << 8 \| 1 << 12,
	Instruction::ADD_INT \| 2 << 8, 0 \| 1 << 8,
	Instruction::RETURN_VOID);

	std::string expected_before =
	"BasicBlock 0, succ: 1\n"
	" 3: IntConstant [15, 22, 8]\n"
	" 5: IntConstant [22, 8]\n"
	" 19: SuspendCheck\n"
	" 20: Goto 1\n"
	"BasicBlock 1, pred: 0, succ: 5, 2\n"
	" 8: GreaterThanOrEqual(3, 5) [9]\n"
	" 9: If(8)\n"
	"BasicBlock 2, pred: 1, succ: 3\n"
	" 12: Goto 3\n"
	"BasicBlock 3, pred: 2, 5, succ: 4\n"
	" 22: Phi(3, 5) [15]\n"
	" 15: Add(22, 3)\n"
	" 17: ReturnVoid\n"
	"BasicBlock 4, pred: 3\n"
	" 18: Exit\n"
	"BasicBlock 5, pred: 1, succ: 3\n"
	" 21: Goto 3\n";

	// Expected difference after dead code elimination.
	diff_t expected_diff = {
	{ " 3: IntConstant [15, 22, 8]\n", " 3: IntConstant [22, 8]\n" },
	{ " 22: Phi(3, 5) [15]\n", " 22: Phi(3, 5)\n" },
	{ " 15: Add(22, 3)\n", removed }
	};
	std::string expected_after = Patch(expected_before, expected_diff);

	TestCode(data, expected_before, expected_after);
	}

	/**
	* Three-register program with jumps leading to the creation of many
	* blocks.
	*
	* The intent of this test is to ensure that all dead instructions are
	* actually pruned at compile-time, thanks to the (backward)
	* post-order traversal of the the dominator tree.
	*
	* 16-bit
	* offset
	* ------
	* v0 <- 0 0. const/4 v0, #+0
	* v1 <- 1 1. const/4 v1, #+1
	* v2 <- v0 + v1 2. add-int v2, v0, v1
	* goto L2 4. goto +4
	* L1: v1 <- v0 + 3 5. add-int/lit16 v1, v0, #+3
	* goto L3 7. goto +4
	* L2: v0 <- v2 + 2 8. add-int/lit16 v0, v2, #+2
	* goto L1 10. goto +(-5)
	* L3: v2 <- v1 + 4 11. add-int/lit16 v2, v1, #+4
	* return 13. return-void
	*/
	TEST(DeadCodeElimination, AdditionsAndInconditionalJumps) {
	const uint16_t data[] = THREE_REGISTERS_CODE_ITEM(
	Instruction::CONST_4 \| 0 << 8 \| 0 << 12,
	Instruction::CONST_4 \| 1 << 8 \| 1 << 12,
	Instruction::ADD_INT \| 2 << 8, 0 \| 1 << 8,
	Instruction::GOTO \| 4 << 8,
	Instruction::ADD_INT_LIT16 \| 1 << 8 \| 0 << 12, 3,
	Instruction::GOTO \| 4 << 8,
	Instruction::ADD_INT_LIT16 \| 0 << 8 \| 2 << 12, 2,
	static_cast<uint16_t>(Instruction::GOTO \| -5 << 8),
	Instruction::ADD_INT_LIT16 \| 2 << 8 \| 1 << 12, 4,
	Instruction::RETURN_VOID);

	std::string expected_before =
	"BasicBlock 0, succ: 1\n"
	" 3: IntConstant [9]\n"
	" 5: IntConstant [9]\n"
	" 13: IntConstant [14]\n"
	" 18: IntConstant [19]\n"
	" 24: IntConstant [25]\n"
	" 29: SuspendCheck\n"
	" 30: Goto 1\n"
	"BasicBlock 1, pred: 0, succ: 3\n"
	" 9: Add(3, 5) [19]\n"
	" 11: Goto 3\n"
	"BasicBlock 2, pred: 3, succ: 4\n"
	" 14: Add(19, 13) [25]\n"
	" 16: Goto 4\n"
	"BasicBlock 3, pred: 1, succ: 2\n"
	" 19: Add(9, 18) [14]\n"
	" 21: SuspendCheck\n"
	" 22: Goto 2\n"
	"BasicBlock 4, pred: 2, succ: 5\n"
	" 25: Add(14, 24)\n"
	" 27: ReturnVoid\n"
	"BasicBlock 5, pred: 4\n"
	" 28: Exit\n";

	// Expected difference after dead code elimination.
	diff_t expected_diff = {
	{ " 13: IntConstant [14]\n", removed },
	{ " 24: IntConstant [25]\n", removed },
	{ " 14: Add(19, 13) [25]\n", removed },
	// The SuspendCheck instruction following this Add instruction
	// inserts the latter in an environment, thus making it "used" and
	// therefore non removable. It ensues that some other Add and
	// IntConstant instructions cannot be removed, as they are direct
	// or indirect inputs of the initial Add instruction.
	{ " 19: Add(9, 18) [14]\n", " 19: Add(9, 18) []\n" },
	{ " 25: Add(14, 24)\n", removed },
	};
	std::string expected_after = Patch(expected_before, expected_diff);

	TestCode(data, expected_before, expected_after);
	}

	} // namespace art