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9de7ec7868
This patch by Antoine Pitrou optimizes the bytecode for conditional branches by
merging the following "POP_TOP" instruction into the conditional jump. For
example, the list comprehension "[x for x in l if not x]" produced the
following bytecode:
1 0 BUILD_LIST 0
3 LOAD_FAST 0 (.0)
>> 6 FOR_ITER 23 (to 32)
9 STORE_FAST 1 (x)
12 LOAD_FAST 1 (x)
15 JUMP_IF_TRUE 10 (to 28)
18 POP_TOP
19 LOAD_FAST 1 (x)
22 LIST_APPEND 2
25 JUMP_ABSOLUTE 6
>> 28 POP_TOP
29 JUMP_ABSOLUTE 6
>> 32 RETURN_VALUE
but after the patch it produces the following bytecode:
1 0 BUILD_LIST 0
3 LOAD_FAST 0 (.0)
>> 6 FOR_ITER 18 (to 27)
9 STORE_FAST 1 (x)
12 LOAD_FAST 1 (x)
15 POP_JUMP_IF_TRUE 6
18 LOAD_FAST 1 (x)
21 LIST_APPEND 2
24 JUMP_ABSOLUTE 6
>> 27 RETURN_VALUE
Notice that not only the code is shorter, but the conditional jump
(POP_JUMP_IF_TRUE) jumps right to the start of the loop instead of going through
the JUMP_ABSOLUTE at the end. "continue" statements are helped
similarly.
Furthermore, the old jump opcodes (JUMP_IF_FALSE, JUMP_IF_TRUE) have been
replaced by two new opcodes:
- JUMP_IF_TRUE_OR_POP, which jumps if true and pops otherwise
- JUMP_IF_FALSE_OR_POP, which jumps if false and pops otherwise
178 lines
4.9 KiB
Python
178 lines
4.9 KiB
Python
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"""
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opcode module - potentially shared between dis and other modules which
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operate on bytecodes (e.g. peephole optimizers).
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"""
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__all__ = ["cmp_op", "hasconst", "hasname", "hasjrel", "hasjabs",
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"haslocal", "hascompare", "hasfree", "opname", "opmap",
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"HAVE_ARGUMENT", "EXTENDED_ARG"]
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cmp_op = ('<', '<=', '==', '!=', '>', '>=', 'in', 'not in', 'is',
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'is not', 'exception match', 'BAD')
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hasconst = []
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hasname = []
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hasjrel = []
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hasjabs = []
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haslocal = []
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hascompare = []
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hasfree = []
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opmap = {}
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opname = [''] * 256
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for op in range(256): opname[op] = '<%r>' % (op,)
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del op
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def def_op(name, op):
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opname[op] = name
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opmap[name] = op
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def name_op(name, op):
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def_op(name, op)
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hasname.append(op)
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def jrel_op(name, op):
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def_op(name, op)
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hasjrel.append(op)
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def jabs_op(name, op):
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def_op(name, op)
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hasjabs.append(op)
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# Instruction opcodes for compiled code
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# Blank lines correspond to available opcodes
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def_op('STOP_CODE', 0)
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def_op('POP_TOP', 1)
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def_op('ROT_TWO', 2)
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def_op('ROT_THREE', 3)
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def_op('DUP_TOP', 4)
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def_op('ROT_FOUR', 5)
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def_op('NOP', 9)
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def_op('UNARY_POSITIVE', 10)
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def_op('UNARY_NEGATIVE', 11)
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def_op('UNARY_NOT', 12)
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def_op('UNARY_INVERT', 15)
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def_op('BINARY_POWER', 19)
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def_op('BINARY_MULTIPLY', 20)
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def_op('BINARY_MODULO', 22)
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def_op('BINARY_ADD', 23)
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def_op('BINARY_SUBTRACT', 24)
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def_op('BINARY_SUBSCR', 25)
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def_op('BINARY_FLOOR_DIVIDE', 26)
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def_op('BINARY_TRUE_DIVIDE', 27)
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def_op('INPLACE_FLOOR_DIVIDE', 28)
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def_op('INPLACE_TRUE_DIVIDE', 29)
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def_op('STORE_MAP', 54)
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def_op('INPLACE_ADD', 55)
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def_op('INPLACE_SUBTRACT', 56)
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def_op('INPLACE_MULTIPLY', 57)
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def_op('INPLACE_MODULO', 59)
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def_op('STORE_SUBSCR', 60)
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def_op('DELETE_SUBSCR', 61)
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def_op('BINARY_LSHIFT', 62)
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def_op('BINARY_RSHIFT', 63)
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def_op('BINARY_AND', 64)
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def_op('BINARY_XOR', 65)
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def_op('BINARY_OR', 66)
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def_op('INPLACE_POWER', 67)
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def_op('GET_ITER', 68)
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def_op('STORE_LOCALS', 69)
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def_op('PRINT_EXPR', 70)
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def_op('LOAD_BUILD_CLASS', 71)
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def_op('INPLACE_LSHIFT', 75)
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def_op('INPLACE_RSHIFT', 76)
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def_op('INPLACE_AND', 77)
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def_op('INPLACE_XOR', 78)
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def_op('INPLACE_OR', 79)
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def_op('BREAK_LOOP', 80)
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def_op('WITH_CLEANUP', 81)
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def_op('RETURN_VALUE', 83)
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def_op('IMPORT_STAR', 84)
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def_op('YIELD_VALUE', 86)
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def_op('POP_BLOCK', 87)
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def_op('END_FINALLY', 88)
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def_op('POP_EXCEPT', 89)
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HAVE_ARGUMENT = 90 # Opcodes from here have an argument:
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name_op('STORE_NAME', 90) # Index in name list
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name_op('DELETE_NAME', 91) # ""
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def_op('UNPACK_SEQUENCE', 92) # Number of tuple items
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jrel_op('FOR_ITER', 93)
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def_op('UNPACK_EX', 94)
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name_op('STORE_ATTR', 95) # Index in name list
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name_op('DELETE_ATTR', 96) # ""
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name_op('STORE_GLOBAL', 97) # ""
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name_op('DELETE_GLOBAL', 98) # ""
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def_op('DUP_TOPX', 99) # number of items to duplicate
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def_op('LOAD_CONST', 100) # Index in const list
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hasconst.append(100)
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name_op('LOAD_NAME', 101) # Index in name list
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def_op('BUILD_TUPLE', 102) # Number of tuple items
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def_op('BUILD_LIST', 103) # Number of list items
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def_op('BUILD_SET', 104) # Number of set items
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def_op('BUILD_MAP', 105) # Number of dict entries (upto 255)
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name_op('LOAD_ATTR', 106) # Index in name list
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def_op('COMPARE_OP', 107) # Comparison operator
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hascompare.append(107)
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name_op('IMPORT_NAME', 108) # Index in name list
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name_op('IMPORT_FROM', 109) # Index in name list
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jrel_op('JUMP_FORWARD', 110) # Number of bytes to skip
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jabs_op('JUMP_IF_FALSE_OR_POP', 111) # Target byte offset from beginning of code
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jabs_op('JUMP_IF_TRUE_OR_POP', 112) # ""
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jabs_op('JUMP_ABSOLUTE', 113) # ""
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jabs_op('POP_JUMP_IF_FALSE', 114) # ""
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jabs_op('POP_JUMP_IF_TRUE', 115) # ""
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name_op('LOAD_GLOBAL', 116) # Index in name list
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jabs_op('CONTINUE_LOOP', 119) # Target address
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jrel_op('SETUP_LOOP', 120) # Distance to target address
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jrel_op('SETUP_EXCEPT', 121) # ""
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jrel_op('SETUP_FINALLY', 122) # ""
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def_op('LOAD_FAST', 124) # Local variable number
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haslocal.append(124)
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def_op('STORE_FAST', 125) # Local variable number
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haslocal.append(125)
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def_op('DELETE_FAST', 126) # Local variable number
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haslocal.append(126)
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def_op('RAISE_VARARGS', 130) # Number of raise arguments (1, 2, or 3)
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def_op('CALL_FUNCTION', 131) # #args + (#kwargs << 8)
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def_op('MAKE_FUNCTION', 132) # Number of args with default values
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def_op('BUILD_SLICE', 133) # Number of items
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def_op('MAKE_CLOSURE', 134)
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def_op('LOAD_CLOSURE', 135)
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hasfree.append(135)
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def_op('LOAD_DEREF', 136)
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hasfree.append(136)
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def_op('STORE_DEREF', 137)
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hasfree.append(137)
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def_op('CALL_FUNCTION_VAR', 140) # #args + (#kwargs << 8)
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def_op('CALL_FUNCTION_KW', 141) # #args + (#kwargs << 8)
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def_op('CALL_FUNCTION_VAR_KW', 142) # #args + (#kwargs << 8)
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def_op('EXTENDED_ARG', 143)
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EXTENDED_ARG = 143
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def_op('LIST_APPEND', 145)
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def_op('SET_ADD', 146)
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def_op('MAP_ADD', 147)
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del def_op, name_op, jrel_op, jabs_op
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