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Normalize jumps in compiler. All forward jumps to use JUMP_FORWARD. (GH-28755)

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Mark Shannon 2021-10-06 13:05:45 +01:00 committed by GitHub
parent c379bc5ec9
commit f6eafe18c0
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 37 additions and 14 deletions
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4
Lib/test/test_dis.py
View file

@ -1046,7 +1046,7 @@ def _prepare_test_cases():
Instruction(opname='COMPARE_OP', opcode=107, arg=4, argval='>', argrepr='>', offset=34, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_JUMP_IF_FALSE', opcode=114, arg=21, argval=42, argrepr='to 42', offset=36, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=38, starts_line=8, is_jump_target=False, positions=None),
Instruction(opname='JUMP_ABSOLUTE', opcode=113, arg=26, argval=52, argrepr='to 52', offset=40, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='JUMP_FORWARD', opcode=110, arg=5, argval=52, argrepr='to 52', offset=40, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='JUMP_ABSOLUTE', opcode=113, arg=4, argval=8, argrepr='to 8', offset=42, starts_line=7, is_jump_target=True, positions=None),
Instruction(opname='LOAD_GLOBAL', opcode=116, arg=1, argval='print', argrepr='print', offset=44, starts_line=10, is_jump_target=True, positions=None),
Instruction(opname='LOAD_CONST', opcode=100, arg=4, argval='I can haz else clause?', argrepr="'I can haz else clause?'", offset=46, starts_line=None, is_jump_target=False, positions=None),
@ -1071,7 +1071,7 @@ def _prepare_test_cases():
Instruction(opname='LOAD_CONST', opcode=100, arg=2, argval=4, argrepr='4', offset=84, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='COMPARE_OP', opcode=107, arg=0, argval='<', argrepr='<', offset=86, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='POP_JUMP_IF_FALSE', opcode=114, arg=46, argval=92, argrepr='to 92', offset=88, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='JUMP_ABSOLUTE', opcode=113, arg=52, argval=104, argrepr='to 104', offset=90, starts_line=17, is_jump_target=False, positions=None),
Instruction(opname='JUMP_FORWARD', opcode=110, arg=6, argval=104, argrepr='to 104', offset=90, starts_line=17, is_jump_target=False, positions=None),
Instruction(opname='LOAD_FAST', opcode=124, arg=0, argval='i', argrepr='i', offset=92, starts_line=11, is_jump_target=True, positions=None),
Instruction(opname='POP_JUMP_IF_TRUE', opcode=115, arg=28, argval=56, argrepr='to 56', offset=94, starts_line=None, is_jump_target=False, positions=None),
Instruction(opname='LOAD_GLOBAL', opcode=116, arg=1, argval='print', argrepr='print', offset=96, starts_line=19, is_jump_target=True, positions=None),

24
Python/ceval.c
View file

@ -4051,19 +4051,18 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, InterpreterFrame *frame, int thr
TARGET(JUMP_ABSOLUTE) {
PREDICTED(JUMP_ABSOLUTE);
if (oparg < INSTR_OFFSET()) {
/* Increment the warmup counter and quicken if warm enough
* _Py_Quicken is idempotent so we don't worry about overflow */
if (!PyCodeObject_IsWarmedUp(co)) {
PyCodeObject_IncrementWarmup(co);
if (PyCodeObject_IsWarmedUp(co)) {
if (_Py_Quicken(co)) {
goto error;
}
int nexti = INSTR_OFFSET();
first_instr = co->co_firstinstr;
next_instr = first_instr + nexti;
assert(oparg < INSTR_OFFSET());
/* Increment the warmup counter and quicken if warm enough
* _Py_Quicken is idempotent so we don't worry about overflow */
if (!PyCodeObject_IsWarmedUp(co)) {
PyCodeObject_IncrementWarmup(co);
if (PyCodeObject_IsWarmedUp(co)) {
if (_Py_Quicken(co)) {
goto error;
}
int nexti = INSTR_OFFSET();
first_instr = co->co_firstinstr;
next_instr = first_instr + nexti;
}
}
JUMPTO(oparg);
@ -4072,6 +4071,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, InterpreterFrame *frame, int thr
}
TARGET(JUMP_ABSOLUTE_QUICK) {
assert(oparg < INSTR_OFFSET());
JUMPTO(oparg);
CHECK_EVAL_BREAKER();
DISPATCH();

23
Python/compile.c
View file

@ -7220,6 +7220,26 @@ assemble_emit(struct assembler *a, struct instr *i)
return 1;
}
static void
normalize_jumps(struct assembler *a)
{
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) {
b->b_visited = 0;
}
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) {
b->b_visited = 1;
if (b->b_iused == 0) {
continue;
}
struct instr *last = &b->b_instr[b->b_iused-1];
if (last->i_opcode == JUMP_ABSOLUTE &&
last->i_target->b_visited == 0
) {
last->i_opcode = JUMP_FORWARD;
}
}
}
static void
assemble_jump_offsets(struct assembler *a, struct compiler *c)
{
@ -7897,6 +7917,9 @@ assemble(struct compiler *c, int addNone)
clean_basic_block(b);
}
/* Order of basic blocks must have been determined by now */
normalize_jumps(&a);
/* Can't modify the bytecode after computing jump offsets. */
assemble_jump_offsets(&a, c);