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/*
* 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 "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);
x86::CodeGeneratorX86 codegen(graph, 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
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