Rework VM dispatch

[rerobika]

Overview:

• VM_OC_* opcodes are removed, now the dispatch is based on the CBC/CBC_EXT opcode
• The common argument decoding is removed, now each opcode resolves it's arguments individually using VM_DECODE_{EXT}_... macros. Whenever an argument is decoded the dispatcher continues with the same opcode increased by VM_OPCODE_DECODED_ARG.
• E.g.: A opcode with 2 literal arguments dispatches as the following:
  • step_1: case opcode: goto resolve_first_literal, opcode increment by VM_OPCODE_DECODED_ARG, dispatch again (Hidden by macro)
  • step_2: case VM_OPCODE_ONE_LITERAL(opcode): goto resolve_second_literal, opcode increment by VM_OPCODE_DECODED_ARG, dispatch again (Hidden by macro)
  • step_3: case VM_OPCODE_TWO_LITERALS (opcode): Opcode handler implementation goes here.
  • The opcode handler implementation goes as the following:

  case VM_OPCODE_TWO_LITERALS (opcode):
  { 
    VM_DECODE_LITERAL_LITERAL (opcode);
   
   /* use left and right value as before */
  }

• The put result block is optimized, each assignment knows whether an ident or property reference should be resolved
• free_left_value and free_both_values labels are removed, due to the extra long jumps they caused to execute 1 or 2 simple calls.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik robert.fancsik@h-lab.eu

[rerobika]

Benchmark	Heap (bytes)	Stack (bytes)	Perf (sec)
3d-cube.js	10992 -> 10992 : 0.000%	14280 -> 14272 : +0.056%	1.090 -> 0.940 : +13.730%
3d-morph.js	289248 -> 289248 : 0.000%	1664 -> 1664 : 0.000%	1.321 -> 1.305 : +1.202%
3d-raytrace.js	119456 -> 119456 : 0.000%	2572 -> 2564 : +0.311%	1.287 -> 1.210 : +5.962%
access-binary-trees.js	27120 -> 27120 : 0.000%	3548 -> 3540 : +0.225%	0.770 -> 0.751 : +2.449%
access-fannkuch.js	1816 -> 1816 : 0.000%	1736 -> 1736 : 0.000%	2.571 -> 2.374 : +7.661%
access-nbody.js	4592 -> 4592 : 0.000%	1824 -> 1824 : 0.000%	1.462 -> 1.357 : +7.211%
bitops-3bit-bits-in-byte.js	1048 -> 1048 : 0.000%	1680 -> 1680 : 0.000%	0.688 -> 0.622 : +9.500%
bitops-bits-in-byte.js	1008 -> 1008 : 0.000%	1680 -> 1680 : 0.000%	0.997 -> 0.907 : +9.050%
bitops-bitwise-and.js	784 -> 784 : 0.000%	1376 -> 1376 : 0.000%	1.259 -> 1.266 : -0.565%
bitops-nsieve-bits.js	61208 -> 61208 : 0.000%	1680 -> 1680 : 0.000%	1.492 -> 1.312 : +12.036%
controlflow-recursive.js	1288 -> 1288 : 0.000%	61584 -> 61576 : +0.013%	0.527 -> 0.503 : +4.432%
crypto-aes.js	28144 -> 28144 : 0.000%	2308 -> 2308 : 0.000%	0.884 -> 0.816 : +7.666%
crypto-md5.js	70896 -> 70896 : 0.000%	1764 -> 1764 : 0.000%	0.729 -> 0.717 : +1.597%
crypto-sha1.js	46240 -> 46240 : 0.000%	1808 -> 1808 : 0.000%	0.750 -> 0.719 : +4.190%
crypto.js	50112 -> 50112 : 0.000%	3200 -> 3192 : +0.250%	8.457 -> 7.814 : +7.603%
date-format-tofte.js	8840 -> 8840 : 0.000%	2136 -> 2136 : 0.000%	0.989 -> 0.953 : +3.629%
date-format-xparb.js	15200 -> 15200 : 0.000%	2664 -> 2664 : 0.000%	0.722 -> 0.726 : -0.582%
deltablue.js	456312 -> 456312 : 0.000%	3592 -> 3584 : +0.223%	5.278 -> 5.173 : +1.991%
math-cordic.js	2064 -> 2064 : 0.000%	1680 -> 1680 : 0.000%	1.668 -> 1.497 : +10.268%
math-partial-sums.js	1528 -> 1528 : 0.000%	1656 -> 1656 : 0.000%	1.188 -> 1.092 : +8.071%
math-spectral-norm.js	3248 -> 3248 : 0.000%	1680 -> 1680 : 0.000%	0.762 -> 0.707 : +7.189%
raytrace.js	22008 -> 22008 : 0.000%	5168 -> 5160 : +0.155%	2.654 -> 2.608 : +1.713%
richards.js	8472 -> 8472 : 0.000%	2156 -> 2148 : +0.371%	0.297 -> 0.288 : +2.974%
string-base64.js	90120 -> 90120 : 0.000%	1728 -> 1728 : 0.000%	1.423 -> 1.405 : +1.303%
string-fasta.js	4400 -> 4400 : 0.000%	1664 -> 1664 : 0.000%	2.837 -> 2.723 : +3.997%
Geometric mean:	12112.27 -> 12112.27 : 0.000%	2581.934 -> 2580.275 : +0.064%	1.251 -> 1.183 : +5.436%

Binary (bytes)	master(79fd540)	patch(352bd15)	Diff
size	239228	243324	+4096 bytes
.rodata	20950	20170	-780 bytes
.dynstr	384	384	0 bytes
.rel.plt	384	384	0 bytes
.interp	25	25	0 bytes
.dynsym	864	864	0 bytes
.gnu.hash	428	428	0 bytes
.text	208744	214208	+5464 bytes
.comment	85	85	0 bytes
.shstrtab	226	226	0 bytes
.data	8	8	0 bytes
.ARM.exidx	8	8	0 bytes
.rel.dyn	16	16	0 bytes
.init	12	12	0 bytes
.got	208	208	0 bytes
.plt	608	608	0 bytes
.note.ABI-tag	32	32	0 bytes
.gnu.version_r	64	64	0 bytes
.bss	1575136	1575136	0 bytes
.fini	8	8	0 bytes
.hash	372	372	0 bytes
.gnu.version	108	108	0 bytes
.fini_array	4	4	0 bytes
.init_array	4	4	0 bytes
.dynamic	248	248	0 bytes
.eh_frame	4	4	0 bytes
.ARM.attributes	53	53	0 bytes