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gh-92619: Fix bug where the compiler duplicates exit blocks unnecessarily #92620

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markshannon merged 2 commits into from
May 10, 2022
Merged

gh-92619: Fix bug where the compiler duplicates exit blocks unnecessarily #92620

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gh-92619: Fix bug where the compiler duplicates exit blocks unnecessa…
iritkatriel May 10, 2022
efb1e4a
📜🤖 Added by blurb_it.
blurb-it[bot] May 10, 2022
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22 changes: 7 additions & 15 deletions Lib/test/test_dis.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1490,7 +1490,7 @@ def _prepare_test_cases():
Instruction(opname='CALL', opcode=171, arg=1, argval=1, argrepr='', offset=368, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=378, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_EXCEPT', opcode=89, arg=None, argval=None, argrepr='', offset=380, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='JUMP_FORWARD', opcode=110, arg=21, argval=426, argrepr='to 426', offset=382, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='JUMP_FORWARD', opcode=110, arg=4, argval=392, argrepr='to 392', offset=382, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='RERAISE', opcode=119, arg=0, argval=0, argrepr='', offset=384, starts_line=22, is_jump_target=True, positions=None),
Instruction(opname='COPY', opcode=120, arg=3, argval=3, argrepr='', offset=386, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_EXCEPT', opcode=89, arg=None, argval=None, argrepr='', offset=388, starts_line=None, is_jump_target=False, positions=None),
Expand All @@ -1502,24 +1502,16 @@ def _prepare_test_cases():
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=420, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='LOAD_CONST', opcode=100, arg=0, argval=None, argrepr='None', offset=422, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='RETURN_VALUE', opcode=83, arg=None, argval=None, argrepr='', offset=424, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='NOP', opcode=9, arg=None, argval=None, argrepr='', offset=426, starts_line=23, is_jump_target=True, positions=None),
Instruction(opname='LOAD_GLOBAL', opcode=116, arg=3, argval='print', argrepr='NULL + print', offset=428, starts_line=28, is_jump_target=False, positions=None),
Instruction(opname='PUSH_EXC_INFO', opcode=35, arg=None, argval=None, argrepr='', offset=426, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='LOAD_GLOBAL', opcode=116, arg=3, argval='print', argrepr='NULL + print', offset=428, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='LOAD_CONST', opcode=100, arg=10, argval="OK, now we're done", argrepr='"OK, now we\'re done"', offset=440, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='PRECALL', opcode=166, arg=1, argval=1, argrepr='', offset=442, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='CALL', opcode=171, arg=1, argval=1, argrepr='', offset=446, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=456, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='LOAD_CONST', opcode=100, arg=0, argval=None, argrepr='None', offset=458, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='RETURN_VALUE', opcode=83, arg=None, argval=None, argrepr='', offset=460, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='PUSH_EXC_INFO', opcode=35, arg=None, argval=None, argrepr='', offset=462, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='LOAD_GLOBAL', opcode=116, arg=3, argval='print', argrepr='NULL + print', offset=464, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='LOAD_CONST', opcode=100, arg=10, argval="OK, now we're done", argrepr='"OK, now we\'re done"', offset=476, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='PRECALL', opcode=166, arg=1, argval=1, argrepr='', offset=478, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='CALL', opcode=171, arg=1, argval=1, argrepr='', offset=482, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=492, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='RERAISE', opcode=119, arg=0, argval=0, argrepr='', offset=494, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='COPY', opcode=120, arg=3, argval=3, argrepr='', offset=496, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_EXCEPT', opcode=89, arg=None, argval=None, argrepr='', offset=498, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='RERAISE', opcode=119, arg=1, argval=1, argrepr='', offset=500, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='RERAISE', opcode=119, arg=0, argval=0, argrepr='', offset=458, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='COPY', opcode=120, arg=3, argval=3, argrepr='', offset=460, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_EXCEPT', opcode=89, arg=None, argval=None, argrepr='', offset=462, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='RERAISE', opcode=119, arg=1, argval=1, argrepr='', offset=464, starts_line=None, is_jump_target=False, positions=None),
]

# One last piece of inspect fodder to check the default line number handling
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1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core and Builtins/2022-05-10-11-34-35.gh-issue-92619.u0V0lY.rst
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@@ -0,0 +1 @@
Make the compiler duplicate an exit block only if none of its instructions have a lineno (previously only the first instruction in the block was checked, leading to unnecessarily duplicated blocks).
10 changes: 9 additions & 1 deletion Python/compile.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9280,7 +9280,15 @@ trim_unused_consts(struct compiler *c, struct assembler *a, PyObject *consts)

static inline int
is_exit_without_lineno(basicblock *b) {
return b->b_exit && b->b_instr[0].i_lineno < 0;
if (!b->b_exit) {
return 0;
}
for (int i = 0; i < b->b_iused; i++) {
if (b->b_instr[i].i_lineno >= 0) {
return 0;
}
}
return 1;
}

/* PEP 626 mandates that the f_lineno of a frame is correct
Expand Down