WIP: Make ClassWriter reusable
Adds a clear() method to ClassWriter to allow the user to
reuse it to write another class without needing to allocate
new buffers for the constant pool, etc.
Furthermore, add a mode that enabled internal reuse of of buffers class writing.
Exposes an overload of toByteArray that does not require
a copy of the internal buffer, but rather returns the ByteVector
directly. ByteVector has been updated to expose its contents
in a read-only manner as a ByteBuffer or a ByteArrayInputStream.
I've made an initial attempt to include this in the benchmark framework.
# VM version: JDK 1.8.0_162, VM 25.162-b12
Benchmark Mode Cnt Score Error Units
GeneratorBenchmark.asm6_1 thrpt 20 874896.336 ± 10360.316 ops/s
GeneratorBenchmark.asm6_1:+memory.used thrpt 20 ≈ 0 bytes
GeneratorBenchmark.asm6_1:·gc.alloc.rate thrpt 20 2777.524 ± 31.962 MB/sec
GeneratorBenchmark.asm6_1:·gc.alloc.rate.norm thrpt 20 5000.001 ± 0.003 B/op
GeneratorBenchmark.asm6_1:·gc.churn.PS_Eden_Space thrpt 20 2689.738 ± 71.334 MB/sec
GeneratorBenchmark.asm6_1:·gc.churn.PS_Eden_Space.norm thrpt 20 4841.558 ± 101.258 B/op
GeneratorBenchmark.asm6_1:·gc.churn.PS_Survivor_Space thrpt 20 0.162 ± 0.044 MB/sec
GeneratorBenchmark.asm6_1:·gc.churn.PS_Survivor_Space.norm thrpt 20 0.291 ± 0.079 B/op
GeneratorBenchmark.asm6_1:·gc.count thrpt 20 264.000 counts
GeneratorBenchmark.asm6_1:·gc.time thrpt 20 176.000 ms
GeneratorBenchmark.asm6_1_reuse thrpt 20 1053280.540 ± 38925.306 ops/s
GeneratorBenchmark.asm6_1_reuse:+memory.used thrpt 20 ≈ 0 bytes
GeneratorBenchmark.asm6_1_reuse:·gc.alloc.rate thrpt 20 1525.059 ± 56.375 MB/sec
GeneratorBenchmark.asm6_1_reuse:·gc.alloc.rate.norm thrpt 20 2280.001 ± 0.002 B/op
GeneratorBenchmark.asm6_1_reuse:·gc.churn.PS_Eden_Space thrpt 20 1455.204 ± 57.245 MB/sec
GeneratorBenchmark.asm6_1_reuse:·gc.churn.PS_Eden_Space.norm thrpt 20 2175.987 ± 47.373 B/op
GeneratorBenchmark.asm6_1_reuse:·gc.churn.PS_Survivor_Space thrpt 20 0.171 ± 0.046 MB/sec
GeneratorBenchmark.asm6_1_reuse:·gc.churn.PS_Survivor_Space.norm thrpt 20 0.257 ± 0.070 B/op
GeneratorBenchmark.asm6_1_reuse:·gc.count thrpt 20 248.000 counts
GeneratorBenchmark.asm6_1_reuse:·gc.time thrpt 20 166.000 ms # VM version: JDK 10.0.1, VM 10.0.1+10
Benchmark Mode Cnt Score Error Units
GeneratorBenchmark.asm6_1 thrpt 20 808490.379 ± 9597.741 ops/s
GeneratorBenchmark.asm6_1:·gc.alloc.rate thrpt 20 2567.604 ± 30.110 MB/sec
GeneratorBenchmark.asm6_1:·gc.alloc.rate.norm thrpt 20 5000.001 ± 0.002 B/op
GeneratorBenchmark.asm6_1:·gc.churn.CodeHeap_'non-profiled_nmethods' thrpt 20 0.008 ± 0.002 MB/sec
GeneratorBenchmark.asm6_1:·gc.churn.CodeHeap_'non-profiled_nmethods'.norm thrpt 20 0.016 ± 0.004 B/op
GeneratorBenchmark.asm6_1:·gc.churn.G1_Old_Gen thrpt 20 2574.135 ± 84.224 MB/sec
GeneratorBenchmark.asm6_1:·gc.churn.G1_Old_Gen.norm thrpt 20 5012.769 ± 155.361 B/op
GeneratorBenchmark.asm6_1:·gc.count thrpt 20 235.000 counts
GeneratorBenchmark.asm6_1:·gc.time thrpt 20 250.000 ms
GeneratorBenchmark.asm6_1_reuse thrpt 20 874917.363 ± 2517.632 ops/s
GeneratorBenchmark.asm6_1_reuse:·gc.alloc.rate thrpt 20 1266.731 ± 4.102 MB/sec
GeneratorBenchmark.asm6_1_reuse:·gc.alloc.rate.norm thrpt 20 2280.001 ± 0.002 B/op
GeneratorBenchmark.asm6_1_reuse:·gc.churn.CodeHeap_'non-profiled_nmethods' thrpt 20 0.004 ± 0.002 MB/sec
GeneratorBenchmark.asm6_1_reuse:·gc.churn.CodeHeap_'non-profiled_nmethods'.norm thrpt 20 0.008 ± 0.004 B/op
GeneratorBenchmark.asm6_1_reuse:·gc.churn.G1_Old_Gen thrpt 20 1266.407 ± 62.495 MB/sec
GeneratorBenchmark.asm6_1_reuse:·gc.churn.G1_Old_Gen.norm thrpt 20 2279.504 ± 113.687 B/op
GeneratorBenchmark.asm6_1_reuse:·gc.count thrpt 20 144.000 counts
GeneratorBenchmark.asm6_1_reuse:·gc.time thrpt 20 147.000 ms