Home | History | Annotate | Download | only in optimizing
      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "arch/x86/instruction_set_features_x86.h"
     18 #include "base/arena_allocator.h"
     19 #include "builder.h"
     20 #include "code_generator.h"
     21 #include "code_generator_x86.h"
     22 #include "dex_file.h"
     23 #include "dex_instruction.h"
     24 #include "driver/compiler_options.h"
     25 #include "nodes.h"
     26 #include "optimizing_unit_test.h"
     27 #include "prepare_for_register_allocation.h"
     28 #include "ssa_liveness_analysis.h"
     29 
     30 namespace art {
     31 
     32 class LivenessTest : public CommonCompilerTest {};
     33 
     34 static void DumpBitVector(BitVector* vector,
     35                           std::ostream& buffer,
     36                           size_t count,
     37                           const char* prefix) {
     38   buffer << prefix;
     39   buffer << '(';
     40   for (size_t i = 0; i < count; ++i) {
     41     buffer << vector->IsBitSet(i);
     42   }
     43   buffer << ")\n";
     44 }
     45 
     46 static void TestCode(const uint16_t* data, const char* expected) {
     47   ArenaPool pool;
     48   ArenaAllocator allocator(&pool);
     49   HGraph* graph = CreateCFG(&allocator, data);
     50   // `Inline` conditions into ifs.
     51   PrepareForRegisterAllocation(graph).Run();
     52   std::unique_ptr<const X86InstructionSetFeatures> features_x86(
     53       X86InstructionSetFeatures::FromCppDefines());
     54   x86::CodeGeneratorX86 codegen(graph, *features_x86.get(), CompilerOptions());
     55   SsaLivenessAnalysis liveness(graph, &codegen);
     56   liveness.Analyze();
     57 
     58   std::ostringstream buffer;
     59   for (HInsertionOrderIterator it(*graph); !it.Done(); it.Advance()) {
     60     HBasicBlock* block = it.Current();
     61     buffer << "Block " << block->GetBlockId() << std::endl;
     62     size_t ssa_values = liveness.GetNumberOfSsaValues();
     63     BitVector* live_in = liveness.GetLiveInSet(*block);
     64     DumpBitVector(live_in, buffer, ssa_values, "  live in: ");
     65     BitVector* live_out = liveness.GetLiveOutSet(*block);
     66     DumpBitVector(live_out, buffer, ssa_values, "  live out: ");
     67     BitVector* kill = liveness.GetKillSet(*block);
     68     DumpBitVector(kill, buffer, ssa_values, "  kill: ");
     69   }
     70   ASSERT_STREQ(expected, buffer.str().c_str());
     71 }
     72 
     73 TEST_F(LivenessTest, CFG1) {
     74   const char* expected =
     75     "Block 0\n"
     76     "  live in: (0)\n"
     77     "  live out: (0)\n"
     78     "  kill: (1)\n"
     79     "Block 1\n"
     80     "  live in: (0)\n"
     81     "  live out: (0)\n"
     82     "  kill: (0)\n"
     83     "Block 2\n"
     84     "  live in: (0)\n"
     85     "  live out: (0)\n"
     86     "  kill: (0)\n";
     87 
     88   // Constant is not used.
     89   const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
     90     Instruction::CONST_4 | 0 | 0,
     91     Instruction::RETURN_VOID);
     92 
     93   TestCode(data, expected);
     94 }
     95 
     96 TEST_F(LivenessTest, CFG2) {
     97   const char* expected =
     98     "Block 0\n"
     99     "  live in: (0)\n"
    100     "  live out: (1)\n"
    101     "  kill: (1)\n"
    102     "Block 1\n"
    103     "  live in: (1)\n"
    104     "  live out: (0)\n"
    105     "  kill: (0)\n"
    106     "Block 2\n"
    107     "  live in: (0)\n"
    108     "  live out: (0)\n"
    109     "  kill: (0)\n";
    110 
    111   const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
    112     Instruction::CONST_4 | 0 | 0,
    113     Instruction::RETURN);
    114 
    115   TestCode(data, expected);
    116 }
    117 
    118 TEST_F(LivenessTest, CFG3) {
    119   const char* expected =
    120     "Block 0\n"  // entry block
    121     "  live in: (000)\n"
    122     "  live out: (110)\n"
    123     "  kill: (110)\n"
    124     "Block 1\n"  // block with add
    125     "  live in: (110)\n"
    126     "  live out: (001)\n"
    127     "  kill: (001)\n"
    128     "Block 2\n"  // block with return
    129     "  live in: (001)\n"
    130     "  live out: (000)\n"
    131     "  kill: (000)\n"
    132     "Block 3\n"  // exit block
    133     "  live in: (000)\n"
    134     "  live out: (000)\n"
    135     "  kill: (000)\n";
    136 
    137   const uint16_t data[] = TWO_REGISTERS_CODE_ITEM(
    138     Instruction::CONST_4 | 3 << 12 | 0,
    139     Instruction::CONST_4 | 4 << 12 | 1 << 8,
    140     Instruction::ADD_INT_2ADDR | 1 << 12,
    141     Instruction::GOTO | 0x100,
    142     Instruction::RETURN);
    143 
    144   TestCode(data, expected);
    145 }
    146 
    147 TEST_F(LivenessTest, CFG4) {
    148   // var a;
    149   // if (0 == 0) {
    150   //   a = 5;
    151   // } else {
    152   //   a = 4;
    153   // }
    154   // return a;
    155   //
    156   // Bitsets are made of:
    157   // (constant0, constant5, constant4, phi)
    158   const char* expected =
    159     "Block 0\n"  // entry block
    160     "  live in: (0000)\n"
    161     "  live out: (1110)\n"
    162     "  kill: (1110)\n"
    163     "Block 1\n"  // block with if
    164     "  live in: (1110)\n"
    165     "  live out: (0110)\n"
    166     "  kill: (0000)\n"
    167     "Block 2\n"  // else block
    168     "  live in: (0010)\n"
    169     "  live out: (0000)\n"
    170     "  kill: (0000)\n"
    171     "Block 3\n"  // then block
    172     "  live in: (0100)\n"
    173     "  live out: (0000)\n"
    174     "  kill: (0000)\n"
    175     "Block 4\n"  // return block
    176     "  live in: (0000)\n"
    177     "  live out: (0000)\n"
    178     "  kill: (0001)\n"
    179     "Block 5\n"  // exit block
    180     "  live in: (0000)\n"
    181     "  live out: (0000)\n"
    182     "  kill: (0000)\n";
    183 
    184   const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
    185     Instruction::CONST_4 | 0 | 0,
    186     Instruction::IF_EQ, 4,
    187     Instruction::CONST_4 | 4 << 12 | 0,
    188     Instruction::GOTO | 0x200,
    189     Instruction::CONST_4 | 5 << 12 | 0,
    190     Instruction::RETURN | 0 << 8);
    191 
    192   TestCode(data, expected);
    193 }
    194 
    195 TEST_F(LivenessTest, CFG5) {
    196   // var a = 0;
    197   // if (0 == 0) {
    198   // } else {
    199   //   a = 4;
    200   // }
    201   // return a;
    202   //
    203   // Bitsets are made of:
    204   // (constant0, constant4, phi)
    205   const char* expected =
    206     "Block 0\n"  // entry block
    207     "  live in: (000)\n"
    208     "  live out: (110)\n"
    209     "  kill: (110)\n"
    210     "Block 1\n"  // block with if
    211     "  live in: (110)\n"
    212     "  live out: (110)\n"
    213     "  kill: (000)\n"
    214     "Block 2\n"  // else block
    215     "  live in: (010)\n"
    216     "  live out: (000)\n"
    217     "  kill: (000)\n"
    218     "Block 3\n"  // return block
    219     "  live in: (000)\n"
    220     "  live out: (000)\n"
    221     "  kill: (001)\n"
    222     "Block 4\n"  // exit block
    223     "  live in: (000)\n"
    224     "  live out: (000)\n"
    225     "  kill: (000)\n"
    226     "Block 5\n"  // block to avoid critical edge. Predecessor is 1, successor is 3.
    227     "  live in: (100)\n"
    228     "  live out: (000)\n"
    229     "  kill: (000)\n";
    230 
    231   const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
    232     Instruction::CONST_4 | 0 | 0,
    233     Instruction::IF_EQ, 3,
    234     Instruction::CONST_4 | 4 << 12 | 0,
    235     Instruction::RETURN | 0 << 8);
    236 
    237   TestCode(data, expected);
    238 }
    239 
    240 TEST_F(LivenessTest, Loop1) {
    241   // Simple loop with one preheader and one back edge.
    242   // var a = 0;
    243   // while (a == a) {
    244   //   a = 4;
    245   // }
    246   // return;
    247   // Bitsets are made of:
    248   // (constant0, constant4, phi)
    249   const char* expected =
    250     "Block 0\n"  // entry block
    251     "  live in: (000)\n"
    252     "  live out: (110)\n"
    253     "  kill: (110)\n"
    254     "Block 1\n"  // pre header
    255     "  live in: (110)\n"
    256     "  live out: (010)\n"
    257     "  kill: (000)\n"
    258     "Block 2\n"  // loop header
    259     "  live in: (010)\n"
    260     "  live out: (010)\n"
    261     "  kill: (001)\n"
    262     "Block 3\n"  // back edge
    263     "  live in: (010)\n"
    264     "  live out: (010)\n"
    265     "  kill: (000)\n"
    266     "Block 4\n"  // return block
    267     "  live in: (000)\n"
    268     "  live out: (000)\n"
    269     "  kill: (000)\n"
    270     "Block 5\n"  // exit block
    271     "  live in: (000)\n"
    272     "  live out: (000)\n"
    273     "  kill: (000)\n";
    274 
    275 
    276   const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
    277     Instruction::CONST_4 | 0 | 0,
    278     Instruction::IF_EQ, 4,
    279     Instruction::CONST_4 | 4 << 12 | 0,
    280     Instruction::GOTO | 0xFD00,
    281     Instruction::RETURN_VOID);
    282 
    283   TestCode(data, expected);
    284 }
    285 
    286 TEST_F(LivenessTest, Loop3) {
    287   // Test that the returned value stays live in a preceding loop.
    288   // var a = 0;
    289   // while (a == a) {
    290   //   a = 4;
    291   // }
    292   // return 5;
    293   // Bitsets are made of:
    294   // (constant0, constant5, constant4, phi)
    295   const char* expected =
    296     "Block 0\n"
    297     "  live in: (0000)\n"
    298     "  live out: (1110)\n"
    299     "  kill: (1110)\n"
    300     "Block 1\n"
    301     "  live in: (1110)\n"
    302     "  live out: (0110)\n"
    303     "  kill: (0000)\n"
    304     "Block 2\n"  // loop header
    305     "  live in: (0110)\n"
    306     "  live out: (0110)\n"
    307     "  kill: (0001)\n"
    308     "Block 3\n"  // back edge
    309     "  live in: (0110)\n"
    310     "  live out: (0110)\n"
    311     "  kill: (0000)\n"
    312     "Block 4\n"  // return block
    313     "  live in: (0100)\n"
    314     "  live out: (0000)\n"
    315     "  kill: (0000)\n"
    316     "Block 5\n"  // exit block
    317     "  live in: (0000)\n"
    318     "  live out: (0000)\n"
    319     "  kill: (0000)\n";
    320 
    321   const uint16_t data[] = TWO_REGISTERS_CODE_ITEM(
    322     Instruction::CONST_4 | 0 | 0,
    323     Instruction::IF_EQ, 4,
    324     Instruction::CONST_4 | 4 << 12 | 0,
    325     Instruction::GOTO | 0xFD00,
    326     Instruction::CONST_4 | 5 << 12 | 1 << 8,
    327     Instruction::RETURN | 1 << 8);
    328 
    329   TestCode(data, expected);
    330 }
    331 
    332 
    333 TEST_F(LivenessTest, Loop4) {
    334   // Make sure we support a preheader of a loop not being the first predecessor
    335   // in the predecessor list of the header.
    336   // var a = 0;
    337   // while (a == a) {
    338   //   a = 4;
    339   // }
    340   // return a;
    341   // Bitsets are made of:
    342   // (constant0, constant4, phi)
    343   const char* expected =
    344     "Block 0\n"
    345     "  live in: (000)\n"
    346     "  live out: (110)\n"
    347     "  kill: (110)\n"
    348     "Block 1\n"
    349     "  live in: (110)\n"
    350     "  live out: (110)\n"
    351     "  kill: (000)\n"
    352     "Block 2\n"  // loop header
    353     "  live in: (010)\n"
    354     "  live out: (011)\n"
    355     "  kill: (001)\n"
    356     "Block 3\n"  // back edge
    357     "  live in: (010)\n"
    358     "  live out: (010)\n"
    359     "  kill: (000)\n"
    360     "Block 4\n"  // pre loop header
    361     "  live in: (110)\n"
    362     "  live out: (010)\n"
    363     "  kill: (000)\n"
    364     "Block 5\n"  // return block
    365     "  live in: (001)\n"
    366     "  live out: (000)\n"
    367     "  kill: (000)\n"
    368     "Block 6\n"  // exit block
    369     "  live in: (000)\n"
    370     "  live out: (000)\n"
    371     "  kill: (000)\n";
    372 
    373   const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
    374     Instruction::CONST_4 | 0 | 0,
    375     Instruction::GOTO | 0x500,
    376     Instruction::IF_EQ, 5,
    377     Instruction::CONST_4 | 4 << 12 | 0,
    378     Instruction::GOTO | 0xFD00,
    379     Instruction::GOTO | 0xFC00,
    380     Instruction::RETURN | 0 << 8);
    381 
    382   TestCode(data, expected);
    383 }
    384 
    385 TEST_F(LivenessTest, Loop5) {
    386   // Make sure we create a preheader of a loop when a header originally has two
    387   // incoming blocks and one back edge.
    388   // Bitsets are made of:
    389   // (constant0, constant5, constant4, phi in block 8)
    390   const char* expected =
    391     "Block 0\n"
    392     "  live in: (0000)\n"
    393     "  live out: (1110)\n"
    394     "  kill: (1110)\n"
    395     "Block 1\n"
    396     "  live in: (1110)\n"
    397     "  live out: (0110)\n"
    398     "  kill: (0000)\n"
    399     "Block 2\n"
    400     "  live in: (0010)\n"
    401     "  live out: (0000)\n"
    402     "  kill: (0000)\n"
    403     "Block 3\n"
    404     "  live in: (0100)\n"
    405     "  live out: (0000)\n"
    406     "  kill: (0000)\n"
    407     "Block 4\n"  // loop header
    408     "  live in: (0001)\n"
    409     "  live out: (0001)\n"
    410     "  kill: (0000)\n"
    411     "Block 5\n"  // back edge
    412     "  live in: (0001)\n"
    413     "  live out: (0001)\n"
    414     "  kill: (0000)\n"
    415     "Block 6\n"  // return block
    416     "  live in: (0001)\n"
    417     "  live out: (0000)\n"
    418     "  kill: (0000)\n"
    419     "Block 7\n"  // exit block
    420     "  live in: (0000)\n"
    421     "  live out: (0000)\n"
    422     "  kill: (0000)\n"
    423     "Block 8\n"  // synthesized pre header
    424     "  live in: (0000)\n"
    425     "  live out: (0001)\n"
    426     "  kill: (0001)\n";
    427 
    428   const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
    429     Instruction::CONST_4 | 0 | 0,
    430     Instruction::IF_EQ, 4,
    431     Instruction::CONST_4 | 4 << 12 | 0,
    432     Instruction::GOTO | 0x200,
    433     Instruction::CONST_4 | 5 << 12 | 0,
    434     Instruction::IF_EQ, 3,
    435     Instruction::GOTO | 0xFE00,
    436     Instruction::RETURN | 0 << 8);
    437 
    438   TestCode(data, expected);
    439 }
    440 
    441 TEST_F(LivenessTest, Loop6) {
    442   // Bitsets are made of:
    443   // (constant0, constant4, constant5, phi in block 2)
    444   const char* expected =
    445     "Block 0\n"
    446     "  live in: (0000)\n"
    447     "  live out: (1110)\n"
    448     "  kill: (1110)\n"
    449     "Block 1\n"
    450     "  live in: (1110)\n"
    451     "  live out: (0110)\n"
    452     "  kill: (0000)\n"
    453     "Block 2\n"  // loop header
    454     "  live in: (0110)\n"
    455     "  live out: (0111)\n"
    456     "  kill: (0001)\n"
    457     "Block 3\n"
    458     "  live in: (0110)\n"
    459     "  live out: (0110)\n"
    460     "  kill: (0000)\n"
    461     "Block 4\n"  // back edge
    462     "  live in: (0110)\n"
    463     "  live out: (0110)\n"
    464     "  kill: (0000)\n"
    465     "Block 5\n"  // back edge
    466     "  live in: (0110)\n"
    467     "  live out: (0110)\n"
    468     "  kill: (0000)\n"
    469     "Block 6\n"  // return block
    470     "  live in: (0001)\n"
    471     "  live out: (0000)\n"
    472     "  kill: (0000)\n"
    473     "Block 7\n"  // exit block
    474     "  live in: (0000)\n"
    475     "  live out: (0000)\n"
    476     "  kill: (0000)\n";
    477 
    478   const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
    479     Instruction::CONST_4 | 0 | 0,
    480     Instruction::IF_EQ, 8,
    481     Instruction::CONST_4 | 4 << 12 | 0,
    482     Instruction::IF_EQ, 4,
    483     Instruction::CONST_4 | 5 << 12 | 0,
    484     Instruction::GOTO | 0xFA00,
    485     Instruction::GOTO | 0xF900,
    486     Instruction::RETURN | 0 << 8);
    487 
    488   TestCode(data, expected);
    489 }
    490 
    491 
    492 TEST_F(LivenessTest, Loop7) {
    493   // Bitsets are made of:
    494   // (constant0, constant4, constant5, phi in block 2, phi in block 6)
    495   const char* expected =
    496     "Block 0\n"
    497     "  live in: (00000)\n"
    498     "  live out: (11100)\n"
    499     "  kill: (11100)\n"
    500     "Block 1\n"
    501     "  live in: (11100)\n"
    502     "  live out: (01100)\n"
    503     "  kill: (00000)\n"
    504     "Block 2\n"  // loop header
    505     "  live in: (01100)\n"
    506     "  live out: (01110)\n"
    507     "  kill: (00010)\n"
    508     "Block 3\n"
    509     "  live in: (01100)\n"
    510     "  live out: (01100)\n"
    511     "  kill: (00000)\n"
    512     "Block 4\n"  // loop exit
    513     "  live in: (00100)\n"
    514     "  live out: (00000)\n"
    515     "  kill: (00000)\n"
    516     "Block 5\n"  // back edge
    517     "  live in: (01100)\n"
    518     "  live out: (01100)\n"
    519     "  kill: (00000)\n"
    520     "Block 6\n"  // return block
    521     "  live in: (00000)\n"
    522     "  live out: (00000)\n"
    523     "  kill: (00001)\n"
    524     "Block 7\n"  // exit block
    525     "  live in: (00000)\n"
    526     "  live out: (00000)\n"
    527     "  kill: (00000)\n"
    528     "Block 8\n"  // synthesized block to avoid critical edge.
    529     "  live in: (00010)\n"
    530     "  live out: (00000)\n"
    531     "  kill: (00000)\n";
    532 
    533   const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
    534     Instruction::CONST_4 | 0 | 0,
    535     Instruction::IF_EQ, 8,
    536     Instruction::CONST_4 | 4 << 12 | 0,
    537     Instruction::IF_EQ, 4,
    538     Instruction::CONST_4 | 5 << 12 | 0,
    539     Instruction::GOTO | 0x0200,
    540     Instruction::GOTO | 0xF900,
    541     Instruction::RETURN | 0 << 8);
    542 
    543   TestCode(data, expected);
    544 }
    545 
    546 TEST_F(LivenessTest, Loop8) {
    547   // var a = 0;
    548   // while (a == a) {
    549   //   a = a + a;
    550   // }
    551   // return a;
    552   //
    553   // We want to test that the ins of the loop exit
    554   // does contain the phi.
    555   // Bitsets are made of:
    556   // (constant0, phi, add)
    557   const char* expected =
    558     "Block 0\n"
    559     "  live in: (000)\n"
    560     "  live out: (100)\n"
    561     "  kill: (100)\n"
    562     "Block 1\n"  // pre loop header
    563     "  live in: (100)\n"
    564     "  live out: (000)\n"
    565     "  kill: (000)\n"
    566     "Block 2\n"  // loop header
    567     "  live in: (000)\n"
    568     "  live out: (010)\n"
    569     "  kill: (010)\n"
    570     "Block 3\n"  // back edge
    571     "  live in: (010)\n"
    572     "  live out: (000)\n"
    573     "  kill: (001)\n"
    574     "Block 4\n"  // return block
    575     "  live in: (010)\n"
    576     "  live out: (000)\n"
    577     "  kill: (000)\n"
    578     "Block 5\n"  // exit block
    579     "  live in: (000)\n"
    580     "  live out: (000)\n"
    581     "  kill: (000)\n";
    582 
    583   const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
    584     Instruction::CONST_4 | 0 | 0,
    585     Instruction::IF_EQ, 6,
    586     Instruction::ADD_INT, 0, 0,
    587     Instruction::GOTO | 0xFB00,
    588     Instruction::RETURN | 0 << 8);
    589 
    590   TestCode(data, expected);
    591 }
    592 
    593 }  // namespace art
    594