For most cases where a conversion specifier doesn't match an argument,
we usually guess that the conversion specifier is wrong. However, if
the argument is an integer type and the specifier is %C, it's likely
the user really did mean to print the integer as a character.
(This is more common than %c because there is no way to specify a unichar
literal -- you have to write an integer literal, such as '0x2603',
and then cast it to unichar.)
This does not change the behavior of %S, since there are fewer cases
where printing a literal Unicode *string* is necessary, but this could
easily be changed in the future.
<rdar://problem/11982013>
llvm-svn: 169400
This warning was failing to fire under ARC because of the implicit
lifetime casts added around the object literal expression.
<rdar://problem/11300873>, again.
llvm-svn: 167648
Previously, the warning would erroneously fire on this:
for (Test *a in someArray)
use(a.weakProp);
...because it looks like the same property is being accessed over and over.
However, clearly this is not the case. We now ignore loops like this for
local variables, but continue to warn if the base object is a parameter,
global variable, or instance variable, on the assumption that these are
not repeatedly usually assigned to within loops.
Additionally, do-while loops where the condition is 'false' are not really
loops at all; usually they're just used for semicolon-swallowing macros or
using "break" like "goto".
<rdar://problem/12578785&12578849>
llvm-svn: 166942
Also, unify ObjCShouldCallSuperDealloc and ObjCShouldCallSuperFinalize.
The two have identical behavior and will never be active at the same time.
There's one last simplification now, which is that if we see a call to
[super foo] and we are currently in a method named 'foo', we will
/unconditionally/ clear the ObjCShouldCallSuper flag, rather than check
first to see if we're in a method where calling super is required. There's
no reason to pay the extra lookup price here.
llvm-svn: 166285
This is a "safe" pattern, or at least one that cannot be helped by using
a strong local variable. However, if the single read is within a loop,
it should /always/ be treated as potentially dangerous.
<rdar://problem/12437490>
llvm-svn: 165719
Previously, [foo weakProp] was not being treated the same as foo.weakProp.
Now, for every explicit message send, we check if it's a property access,
and if so, if the property is weak. Then for every assignment of a
message, we have to do the same thing again.
This is a potentially expensive increase because determining whether a
method is a property accessor requires searching through the methods it
overrides. However, without it -Warc-repeated-use-of-weak will miss cases
from people who prefer not to use dot syntax. If this turns out to be
too expensive, we can try caching the result somewhere, or even lose
precision by not checking superclass methods. The warning is off-by-default,
though.
<rdar://problem/12407765>
llvm-svn: 165718
Then, switch users of PropertyIfSetterOrGetter and LookupPropertyDecl
(the latter by name) over to findPropertyDecl. This actually makes
-Wreceiver-is-weak a bit stronger than it was before.
llvm-svn: 165628
Old algorithm:
1. See if the name looks like a getter or setter.
2. Use the name to look up a property in the current ObjCContainer
and all its protocols.
3. If the current container is an interface, also look in all categories
and superclasses (and superclass categories, and so on).
New algorithm:
1. See if the method is marked as a property accessor. If so, look through
all properties in the current container and find one that has a matching
selector.
2. Find all overrides of the method using ObjCMethodDecl's
getOverriddenMethods. This collects methods in superclasses and protocols
(as well as superclass categories, which isn't really necessary), and
checks if THEY are accessors. This part is not done recursively, since
getOverriddenMethods is already recursive.
This lets us handle getters and setters that do not match the property
names.
llvm-svn: 165627
New output:
warning: weak property may be unpredictably set to nil
note: property declared here
note: assign the value to a strong variable to keep the object alive
during use
<rdar://problem/12277204>
llvm-svn: 164857
Like properties, loading from a weak ivar twice in the same function can
give you inconsistent results if the object is deallocated between the
two loads. It is safer to assign to a strong local variable and use that.
Second half of <rdar://problem/12280249>.
llvm-svn: 164855
The motivating example:
if (self.weakProp)
use(self.weakProp);
As with any non-atomic test-then-use, it is possible a weak property to be
non-nil at the 'if', but be deallocated by the time it is used. The correct
way to write this example is as follows:
id tmp = self.weakProp;
if (tmp)
use(tmp);
The warning is controlled by -Warc-repeated-use-of-receiver, and uses the
property name and base to determine if the same property on the same object
is being accessed multiple times. In cases where the base is more
complicated than just a single Decl (e.g. 'foo.bar.weakProp'), it picks a
Decl for some degree of uniquing and reports the problem under a subflag,
-Warc-maybe-repeated-use-of-receiver. This gives a way to tune the
aggressiveness of the warning for a particular project.
The warning is not on by default because it is not flow-sensitive and thus
may have a higher-than-acceptable rate of false positives, though it is
less noisy than -Wreceiver-is-weak. On the other hand, it will not warn
about some cases that may be legitimate issues that -Wreceiver-is-weak
will catch, and it does not attempt to reason about methods returning weak
values.
Even though this is not a real "analysis-based" check I've put the bug
emission code in AnalysisBasedWarnings for two reasons: (1) to run on
every kind of code body (function, method, block, or lambda), and (2) to
suggest that it may be enhanced by flow-sensitive analysis in the future.
The second (smaller) half of this work is to extend it to weak locals
and weak ivars. This should use most of the same infrastructure.
Part of <rdar://problem/12280249>
llvm-svn: 164854
Retain cycles happen in the case where a block is persisted past its
life on the stack, and the way that occurs is by copying the block.
We should thus look through any explicit copies we see.
Note that Block_copy is actually a type-safe wrapper for _Block_copy,
which does all the real work.
<rdar://problem/12219663>
llvm-svn: 164039
Specifically, this should warn:
__block block_t a = ^{ a(); };
Furthermore, this case which previously warned now does not, since the value
of 'b' is captured before the assignment occurs:
block_t b; // not __block
b = ^{ b(); };
(This will of course warn under -Wuninitialized, as before.)
<rdar://problem/11015883>
llvm-svn: 163962
Objective-C related to NSException.
Fixes <rdar://problem/12287498>
I debated whether or not this logic should be sunk into the CFG
itself. It's not clear if we should, as different analyses may
wish to have different policies. We can re-evaluate this in the
future.
llvm-svn: 163760
in classes. Use it to flag those method implementations which don't
contain call to 'super' if they have 'super' class and it has the method
with this attribute set. This is wip. // rdar://6386358
llvm-svn: 163434
Jordan Rose