py/emitnative: Initialise locals as Python object type for native code.

In @micropython.native code the types of variables and expressions are
always Python objects, so they can be initialised as such.  This prevents
problems with compiling optimised code like while-loops where a local may
be referenced before it is assigned to.

Signed-off-by: Damien George <damien@micropython.org>
This commit is contained in:
Damien George 2022-12-15 16:11:27 +11:00
parent ed58d6e4ce
commit 910f579403
3 changed files with 14 additions and 1 deletions

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@ -401,7 +401,7 @@ STATIC void emit_native_start_pass(emit_t *emit, pass_kind_t pass, scope_t *scop
// local variables begin unbound, and have unknown type
for (mp_uint_t i = num_args; i < emit->local_vtype_alloc; i++) {
emit->local_vtype[i] = VTYPE_UNBOUND;
emit->local_vtype[i] = emit->do_viper_types ? VTYPE_UNBOUND : VTYPE_PYOBJ;
}
// values on stack begin unbound

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@ -12,6 +12,17 @@ x = 1
print(x, x := 5, x)
print(x)
# Test "while" with assignment expression as conditional, assigning to a new local.
# The while conditional is compiled after the while body, so this tests how the
# compiler handles the case of an unbound local being compiled before it is assigned.
def f():
l = [0, 1]
while local := len(l):
print(local, l.pop())
f()
def foo():
print("any", any((hit := i) % 5 == 3 and (hit % 2) == 0 for i in range(10)))

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@ -5,6 +5,8 @@ True
5
1 5 5
5
2 1
1 0
any True
8
123