[analyzer] Suppress nullability warning for _Nonnull locals zero-initialized by ObjC ARC.
Prevent the analyzer from warning when a _Nonnnull local variable is implicitly
zero-initialized because of Objective-C automated reference counting. This avoids false
positives in cases where a _Nonnull local variable cannot be initialized with an
initialization expression, such as:
NSString * _Nonnull s; // no-warning
@autoreleasepool {
s = ...;
}
The nullability checker will still warn when a _Nonnull local variable is explicitly
initialized with nil.
This suppression introduces the potential for false negatives if the local variable
is used before it is assigned a _Nonnull value. Based on a discussion with Anna Zaks,
Jordan Rose, and John McCall, I've added a FIXME to treat implicitly zero-initialized
_Nonnull locals as uninitialized in Sema's UninitializedValues analysis to avoid these
false negatives.
rdar://problem/23522311
llvm-svn: 256603
diff --git a/clang/test/Analysis/nullability.mm b/clang/test/Analysis/nullability.mm
index d0428d4..2c29d00 100644
--- a/clang/test/Analysis/nullability.mm
+++ b/clang/test/Analysis/nullability.mm
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -analyze -analyzer-checker=core,nullability -verify %s
+// RUN: %clang_cc1 -fobjc-arc -analyze -analyzer-checker=core,nullability -verify %s
#define nil 0
#define BOOL int
@@ -278,3 +278,12 @@
return p;
}
+
+void testObjCARCImplicitZeroInitialization() {
+ TestObject * _Nonnull implicitlyZeroInitialized; // no-warning
+ implicitlyZeroInitialized = getNonnullTestObject();
+}
+
+void testObjCARCExplicitZeroInitialization() {
+ TestObject * _Nonnull explicitlyZeroInitialized = nil; // expected-warning {{Null is assigned to a pointer which is expected to have non-null value}}
+}