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Simplify BREAK_LOOP detection...

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by making more us of linestart. At least for now...
This commit is contained in:
rocky
2024-07-14 14:45:25 -04:00
parent 04da2fb8df
commit d731d32c11
5 changed files with 94 additions and 50 deletions
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3
uncompyle6/scanners/scanner2.py
View File

@@ -495,7 +495,8 @@ class Scanner2(Scanner):
if show_asm in ("both", "after"):
print("\n# ---- tokenization:")
for t in new_tokens:
# FIXME: t.format() is changing tokens!
for t in new_tokens.copy():
print(t.format(line_prefix=""))
print()
return new_tokens, customize

3
uncompyle6/scanners/scanner26.py
View File

@@ -353,7 +353,8 @@ class Scanner26(scan.Scanner2):
if show_asm in ("both", "after"):
print("\n# ---- tokenization:")
for t in tokens:
# FIXME: t.format() is changing tokens!
for t in tokens.copy():
print(t.format(line_prefix=""))
print()
return tokens, customize

3
uncompyle6/scanners/scanner3.py
View File

@@ -797,7 +797,8 @@ class Scanner3(Scanner):
if show_asm in ("both", "after"):
print("\n# ---- tokenization:")
for t in new_tokens:
# FIXME: t.format() is changing tokens!
for t in new_tokens.copy():
print(t.format(line_prefix=""))
print()
return new_tokens, customize

86
uncompyle6/scanners/scanner37base.py
View File

@@ -228,13 +228,13 @@ class Scanner37Base(Scanner):
if show_asm in ("both", "before"):
print("\n# ---- disassembly:")
self.insts = bytecode.disassemble_bytes(
bytecode.disassemble_bytes(
co.co_code,
varnames=co.co_varnames,
names=co.co_names,
constants=co.co_consts,
cells=bytecode._cell_names,
linestarts=bytecode._linestarts,
line_starts=bytecode._linestarts,
asm_format="extended",
filename=co.co_filename,
show_source=True,
@@ -481,12 +481,17 @@ class Scanner37Base(Scanner):
next_opname = self.insts[i + 1].opname
# 'Continue's include jumps to loops that are not
# and the end of a block which follow with POP_BLOCK and COME_FROM_LOOP.
# If the JUMP_ABSOLUTE is to a FOR_ITER and it is followed by another JUMP_FORWARD
# then we'll take it as a "continue".
is_continue = (
self.insts[self.offset2inst_index[target]].opname == "FOR_ITER"
and self.insts[i + 1].opname == "JUMP_FORWARD"
# and the end of a block which follow with
# POP_BLOCK and COME_FROM_LOOP. If the
# JUMP_ABSOLUTE is to a FOR_ITER, and it is
# followed by another JUMP_FORWARD then we'll take
# it as a "continue".
next_inst = self.insts[i + 1]
is_continue = self.insts[
self.offset2inst_index[target]
].opname == "FOR_ITER" and next_inst.opname in (
"JUMP_FORWARD",
"JUMP_ABSOLUTE",
)
if self.version < (3, 8) and (
@@ -501,21 +506,65 @@ class Scanner37Base(Scanner):
):
opname = "CONTINUE"
else:
# "continue" versus "break_loop" dectction is more complicated
# because "continue" to an outer loop is really a "break loop"
opname = "JUMP_BACK"
# FIXME: this is a hack to catch stuff like:
# if x: continue
# the "continue" is not on a new line.
# There are other situations where we don't catch
# CONTINUE as well.
if tokens[-1].kind == "JUMP_BACK" and tokens[-1].attr <= argval:
#
# Another situation is where we have
# for method in methods:
# for B in method:
# if c:
# return
# break # A "continue" but not the innermost one
if tokens[-1].kind == "JUMP_LOOP" and tokens[-1].attr <= argval:
if tokens[-2].kind == "BREAK_LOOP":
del tokens[-1]
j -= 1
else:
# intern is used because we are changing the *previous* token
tokens[-1].kind = sys.intern("CONTINUE")
if last_op_was_break and opname == "CONTINUE":
last_op_was_break = False
continue
# "intern" is used because we are
# changing the *previous* token. A
# POP_TOP suggests a "break" rather
# than a "continue"?
if tokens[-2] == "POP_TOP" and (
is_continue and next_inst.argval != tokens[-1].attr
):
tokens[-1].kind = sys.intern("BREAK_LOOP")
else:
tokens[-1].kind = sys.intern("CONTINUE")
last_continue = tokens[-1]
pass
pass
pass
# elif (
# last_continue is not None
# and tokens[-1].kind == "JUMP_LOOP"
# and last_continue.attr <= tokens[-1].attr
# and last_continue.offset > tokens[-1].attr
# ):
# # Handle mis-characterized "CONTINUE"
# # We have a situation like:
# # loop ... for or while)
# # loop
# # if ...: # code below starts here
# # break # not continue
# #
# # POP_JUMP_IF_FALSE_LOOP # to outer loop
# # JUMP_LOOP # to inner loop
# # ...
# # JUMP_LOOP # to outer loop
# tokens[-2].kind = sys.intern("BREAK_LOOP")
# pass
# if last_op_was_break and opname == "CONTINUE":
# last_op_was_break = False
# continue
pass
else:
opname = "JUMP_FORWARD"
elif inst.offset in self.load_asserts:
opname = "LOAD_ASSERT"
@@ -538,9 +587,10 @@ class Scanner37Base(Scanner):
)
pass
if show_asm in ("both", "after"):
if show_asm in ("both", "after") and self.version < (3, 8):
print("\n# ---- tokenization:")
for t in tokens:
# FIXME: t.format() is changing tokens!
for t in tokens.copy():
print(t.format(line_prefix=""))
print()
return tokens, customize

49
uncompyle6/scanners/scanner38.py
View File

@@ -24,13 +24,13 @@ scanner routine for Python 3.7 and up.
from typing import Dict, Tuple
from uncompyle6.scanners.tok import off2int
from uncompyle6.scanners.scanner37 import Scanner37
from uncompyle6.scanners.scanner37base import Scanner37Base
# bytecode verification, verify(), uses JUMP_OPs from here
from xdis.opcodes import opcode_38 as opc
from uncompyle6.scanners.scanner37 import Scanner37
from uncompyle6.scanners.scanner37base import Scanner37Base
from uncompyle6.scanners.tok import off2int
# bytecode verification, verify(), uses JUMP_OPS from here
JUMP_OPs = opc.JUMP_OPS
@@ -121,35 +121,26 @@ class Scanner38(Scanner37):
new_tokens.append(token)
continue
# We also want to avoid confusing BREAK_LOOPS with parts of the
# grammar rules for loops. (Perhaps we should change the grammar.)
# Try to find an adjacent JUMP_BACK which is part of the normal loop end.
j = i
while tokens[j - 1] in ("POP_TOP", "POP_BLOCK", "POP_EXCEPT"):
j -= 1
if tokens[j].linestart:
break
token_with_linestart = tokens[j]
if i + 1 < len(tokens) and tokens[i + 1] == "JUMP_BACK":
# Sometimes the jump back is after the "break" instruction..
jump_back_index = i + 1
else:
# and sometimes, because of jump-to-jump optimization, it is before the
# jump target instruction.
jump_back_index = self.offset2tok_index[jump_target] - 1
while tokens[jump_back_index].kind.startswith("COME_FROM_"):
jump_back_index -= 1
pass
pass
jump_back_token = tokens[jump_back_index]
# Is this a forward jump not next to a JUMP_BACK ? ...
break_loop = token.linestart and jump_back_token != "JUMP_BACK"
# or if there is looping jump back, then that loop
# should start before where the "break" instruction sits.
if break_loop or (
jump_back_token == "JUMP_BACK"
and jump_back_token.attr < token.off2int()
):
if token_with_linestart.linestart:
token.kind = "BREAK_LOOP"
pass
new_tokens.append(token)
if show_asm in ("both", "after"):
print("\n# ---- tokenization:")
# FIXME: t.format() is changing tokens!
for t in new_tokens.copy():
print(t.format(line_prefix=""))
print()
return new_tokens, customize