Allow returning void expressions where state changes are allowed

In the same places as state changes are allowed, i.e. in places where a parent of the AST node is a WHILE/DO/FOR or an IF without ELSE, it's allowed to use return statements with expressions that return void, e.g. llDie(), provided the function itself is declared as returning void.

The construction, when found, is rewritten to '{<void expression>; return;}' because the optimizer is not designed to deal with these monsters.

We've renamed the variable SuspiciousStSw to PruneBug, because it's used for both purposes now, though a better name might have been PruneBugPendingChecks, because these are only errors if the IF has an ELSE. We've also added the exception to raise as part of the data stored in the list.

Per report by Tonaie Resident.
This commit is contained in:
Sei Lisa 2019-05-01 04:03:58 +02:00
parent 3cfbbb923c
commit 9d540798b4
5 changed files with 183 additions and 14 deletions

View file

@ -1791,7 +1791,8 @@ list lazy_list_set(list L, integer i, list v)
if AllowStSw is False:
raise EParseCantChangeState(self)
if AllowStSw is None:
self.SuspiciousStSw.append(self.errorpos)
self.PruneBug.append((self.errorpos,
EParseCantChangeState))
self.NextToken()
if self.tok[0] not in ('DEFAULT', 'IDENT'):
raise EParseSyntax(self)
@ -1812,12 +1813,31 @@ list lazy_list_set(list L, integer i, list v)
value = None
else:
savepos = self.errorpos
saveAllowVoid = self.allowVoid
# Needed due to another LSL bug, see regr/void-in-return.lsl
self.allowVoid = True
value = self.Parse_expression()
self.allowVoid = saveAllowVoid
self.expect(';')
self.NextToken()
if ReturnType is None and value is not None:
self.errorpos = savepos
raise EParseReturnShouldBeEmpty(self)
# It follows the same rules as AllowStSw
if AllowStSw is False:
self.errorpos = savepos
raise EParseReturnShouldBeEmpty(self)
elif value.t is None:
if AllowStSw is None:
self.PruneBug.append((self.errorpos,
EParseReturnShouldBeEmpty))
self.PushScope()
scope = self.scopeindex
self.PopScope()
return nr(nt='{}', t=None, scope=scope,
ch=[nr(nt='EXPR', t=None, ch=[value]),
nr(nt='RETURN', t=None)])
else:
self.errorpos = savepos
raise EParseTypeMismatch(self)
if ReturnType is not None and value is None:
self.errorpos = savepos
raise EParseReturnIsEmpty(self)
@ -1835,22 +1855,22 @@ list lazy_list_set(list L, integer i, list v)
ret.ch.append(self.Parse_expression())
self.expect(')')
self.NextToken()
saveSuspiciousStSw = self.SuspiciousStSw
self.SuspiciousStSw = []
savePruneBug = self.PruneBug
self.PruneBug = []
ret.ch.append(self.Parse_statement(ReturnType, AllowStSw = None, InsideLoop = InsideLoop))
if self.tok[0] == 'ELSE':
if AllowStSw is False and self.SuspiciousStSw:
self.errorpos = self.SuspiciousStSw[0]
raise EParseCantChangeState(self)
if AllowStSw is False and self.PruneBug:
self.errorpos = self.PruneBug[0][0]
raise self.PruneBug[0][1](self)
LastIsReturn = getattr(ret.ch[1], 'LIR', False)
self.NextToken()
ret.ch.append(self.Parse_statement(ReturnType,
AllowStSw = AllowStSw, InsideLoop = InsideLoop))
if AllowStSw is None:
saveSuspiciousStSw += self.SuspiciousStSw
savePruneBug += self.PruneBug
if LastIsReturn and getattr(ret.ch[2], 'LIR', False):
ret.LIR = True
self.SuspiciousStSw = saveSuspiciousStSw
self.PruneBug = savePruneBug
return ret
if tok0 == 'WHILE':
@ -2915,8 +2935,10 @@ list lazy_list_set(list L, integer i, list v)
# List of preprocessor #line directives.
self.linedir = []
# List of positions with suspicious state change statements.
self.SuspiciousStSw = []
# List of tuples (position, exception) where suspicious state change
# statements or returns with void expressions happen. These can only
# be detected when the 'else' is found.
self.PruneBug = []
# This is a small hack to prevent circular definitions in globals when
# extended expressions are enabled. When false (default), forward

View file

@ -368,8 +368,19 @@ class UnitTestRegression(UnitTestCase):
parser.parse('default{timer(){[llDie()];}}')
parser.parse('default{timer(){llDie();}}')
parser.parse('default{timer(){(llDie());}}')
parser.parse('default{timer(){for(llDie();1;llDie());}}'
, ('optimize',))
parser.parse('default{timer(){for(llDie();1;llDie());}}',
('optimize',))
# 'return <void expr>' works in the same situations as state changes
self.assertRaises(lslparse.EParseReturnShouldBeEmpty, parser.parse,
'default{timer(){return llDie();}}')
self.assertRaises(lslparse.EParseReturnShouldBeEmpty, parser.parse,
'default{timer(){if(1)return llDie();else;}}')
self.assertRaises(lslparse.EParseReturnShouldBeEmpty, parser.parse,
'default{timer(){if(1);else return llDie();}}')
self.assertRaises(lslparse.EParseReturnShouldBeEmpty, parser.parse,
'default{timer(){return 1;}}')
self.assertRaises(lslparse.EParseTypeMismatch, parser.parse,
'default{timer(){if(1)return 1;}}')
class UnitTestCoverage(UnitTestCase):
def test_coverage_misc(self):

View file

@ -0,0 +1,41 @@
x(){
// All these should work
if (1)
return llDie();
while (1)
return llDie();
do
return llDie();
while (1);
for (;1;)
return llDie();
if (1)
{
return llDie();
if (1) return llDie(); else return llDie();
return llDie();
}
}
default
{
state_entry()
{
// Similarly, all these should work
if (1)
return llDie();
while (1)
return llDie();
do
return llDie();
while (1);
for (;1;)
return llDie();
if (1)
{
return llDie();
if (1) return llDie(); else return llDie();
return llDie();
}
}
}

View file

@ -0,0 +1,94 @@
x()
{
if (1)
{
llDie();
return;
}
while (1)
{
llDie();
return;
}
do
{
llDie();
return;
}
while (1);
for (; 1; )
{
llDie();
return;
}
if (1)
{
{
llDie();
return;
}
if (1)
{
llDie();
return;
}
else
{
llDie();
return;
}
{
llDie();
return;
}
}
}
default
{
state_entry()
{
if (1)
{
llDie();
return;
}
while (1)
{
llDie();
return;
}
do
{
llDie();
return;
}
while (1);
for (; 1; )
{
llDie();
return;
}
if (1)
{
{
llDie();
return;
}
if (1)
{
llDie();
return;
}
else
{
llDie();
return;
}
{
llDie();
return;
}
}
}
}

View file

@ -0,0 +1 @@
main.py - -O -optimize