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Code Issues Releases Activity
b173f7853e
cpython/Python/opcode_targets.h
Jeffrey Yasskin 9de7ec7868 http://bugs.python.org/issue4715 
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Furthermore, the old jump opcodes (JUMP_IF_FALSE, JUMP_IF_TRUE) have been
replaced by two new opcodes: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
2009-02-25 02:25:04 +00:00

259 lines
5.4 KiB
C
Raw Blame History

static void *opcode_targets[256] = {
&&_unknown_opcode,
&&TARGET_POP_TOP,
&&TARGET_ROT_TWO,
&&TARGET_ROT_THREE,
&&TARGET_DUP_TOP,
&&TARGET_ROT_FOUR,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&TARGET_NOP,
&&TARGET_UNARY_POSITIVE,
&&TARGET_UNARY_NEGATIVE,
&&TARGET_UNARY_NOT,
&&_unknown_opcode,
&&_unknown_opcode,
&&TARGET_UNARY_INVERT,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&TARGET_BINARY_POWER,
&&TARGET_BINARY_MULTIPLY,
&&_unknown_opcode,
&&TARGET_BINARY_MODULO,
&&TARGET_BINARY_ADD,
&&TARGET_BINARY_SUBTRACT,
&&TARGET_BINARY_SUBSCR,
&&TARGET_BINARY_FLOOR_DIVIDE,
&&TARGET_BINARY_TRUE_DIVIDE,
&&TARGET_INPLACE_FLOOR_DIVIDE,
&&TARGET_INPLACE_TRUE_DIVIDE,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&TARGET_STORE_MAP,
&&TARGET_INPLACE_ADD,
&&TARGET_INPLACE_SUBTRACT,
&&TARGET_INPLACE_MULTIPLY,
&&_unknown_opcode,
&&TARGET_INPLACE_MODULO,
&&TARGET_STORE_SUBSCR,
&&TARGET_DELETE_SUBSCR,
&&TARGET_BINARY_LSHIFT,
&&TARGET_BINARY_RSHIFT,
&&TARGET_BINARY_AND,
&&TARGET_BINARY_XOR,
&&TARGET_BINARY_OR,
&&TARGET_INPLACE_POWER,
&&TARGET_GET_ITER,
&&TARGET_STORE_LOCALS,
&&TARGET_PRINT_EXPR,
&&TARGET_LOAD_BUILD_CLASS,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&TARGET_INPLACE_LSHIFT,
&&TARGET_INPLACE_RSHIFT,
&&TARGET_INPLACE_AND,
&&TARGET_INPLACE_XOR,
&&TARGET_INPLACE_OR,
&&TARGET_BREAK_LOOP,
&&TARGET_WITH_CLEANUP,
&&_unknown_opcode,
&&TARGET_RETURN_VALUE,
&&TARGET_IMPORT_STAR,
&&_unknown_opcode,
&&TARGET_YIELD_VALUE,
&&TARGET_POP_BLOCK,
&&TARGET_END_FINALLY,
&&TARGET_POP_EXCEPT,
&&TARGET_STORE_NAME,
&&TARGET_DELETE_NAME,
&&TARGET_UNPACK_SEQUENCE,
&&TARGET_FOR_ITER,
&&TARGET_UNPACK_EX,
&&TARGET_STORE_ATTR,
&&TARGET_DELETE_ATTR,
&&TARGET_STORE_GLOBAL,
&&TARGET_DELETE_GLOBAL,
&&TARGET_DUP_TOPX,
&&TARGET_LOAD_CONST,
&&TARGET_LOAD_NAME,
&&TARGET_BUILD_TUPLE,
&&TARGET_BUILD_LIST,
&&TARGET_BUILD_SET,
&&TARGET_BUILD_MAP,
&&TARGET_LOAD_ATTR,
&&TARGET_COMPARE_OP,
&&TARGET_IMPORT_NAME,
&&TARGET_IMPORT_FROM,
&&TARGET_JUMP_FORWARD,
&&TARGET_JUMP_IF_FALSE_OR_POP,
&&TARGET_JUMP_IF_TRUE_OR_POP,
&&TARGET_JUMP_ABSOLUTE,
&&TARGET_POP_JUMP_IF_FALSE,
&&TARGET_POP_JUMP_IF_TRUE,
&&TARGET_LOAD_GLOBAL,
&&_unknown_opcode,
&&_unknown_opcode,
&&TARGET_CONTINUE_LOOP,
&&TARGET_SETUP_LOOP,
&&TARGET_SETUP_EXCEPT,
&&TARGET_SETUP_FINALLY,
&&_unknown_opcode,
&&TARGET_LOAD_FAST,
&&TARGET_STORE_FAST,
&&TARGET_DELETE_FAST,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&TARGET_RAISE_VARARGS,
&&TARGET_CALL_FUNCTION,
&&TARGET_MAKE_FUNCTION,
&&TARGET_BUILD_SLICE,
&&TARGET_MAKE_CLOSURE,
&&TARGET_LOAD_CLOSURE,
&&TARGET_LOAD_DEREF,
&&TARGET_STORE_DEREF,
&&_unknown_opcode,
&&_unknown_opcode,
&&TARGET_CALL_FUNCTION_VAR,
&&TARGET_CALL_FUNCTION_KW,
&&TARGET_CALL_FUNCTION_VAR_KW,
&&TARGET_EXTENDED_ARG,
&&_unknown_opcode,
&&TARGET_LIST_APPEND,
&&TARGET_SET_ADD,
&&TARGET_MAP_ADD,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode
};
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