Treat invocations of copy & isEqual selectors as safe.

Author: rniwa

clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefCallArgsChecker.cpp

@@ -177,13 +177,18 @@ class RawPtrRefCallArgsChecker
       return;
 
     auto Selector = E->getSelector();
+    auto SelName = Selector.getNameForSlot(0);
+    bool IsSafeSel = SelName.starts_with("copy") || SelName.contains("Copy") ||
+                     SelName == "isEqual" || SelName == "isEqualToString";
+    if (Selector.getNumArgs() <= 1 && IsSafeSel)
+      return; // These selectors are assumed to be readonly.
+
     if (auto *Receiver = E->getInstanceReceiver()) {
       std::optional<bool> IsUnsafe = isUnsafePtr(E->getReceiverType());
       if (IsUnsafe && *IsUnsafe && !isPtrOriginSafe(Receiver)) {
         if (auto *InnerMsg =
                 dyn_cast<ObjCMessageExpr>(Receiver->IgnoreParenCasts())) {
           auto InnerSelector = InnerMsg->getSelector();
-          auto SelName = Selector.getNameForSlot(0);
           if (InnerSelector.getNameForSlot(0).starts_with("alloc") &&
               (SelName.starts_with("init") || SelName.starts_with("_init")))
             return;

clang/test/Analysis/Checkers/WebKit/objc-mock-types.h

@@ -146,6 +146,8 @@ __attribute__((objc_root_class))
 - ( const char *)UTF8String;
 - (id)initWithUTF8String:(const char *)nullTerminatedCString;
 - (NSString *)copy;
+- (NSString *)mutableCopy;
+- (BOOL)isEqualToString:(NSString *)aString;
 + (id)stringWithUTF8String:(const char *)nullTerminatedCString;
 @end
 
@@ -168,6 +170,7 @@ __attribute__((objc_root_class))
 + (SomeObj *)sharedInstance;
 - (instancetype)_init;
 - (SomeObj *)mutableCopy;
+- (BOOL)isEqual:(SomeObj *)other;
 - (SomeObj *)copyWithValue:(int)value;
 - (void)doWork;
 - (SomeObj *)other;

clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm

@@ -6,6 +6,8 @@
 SomeObj *provide();
 void consume_obj(SomeObj*);
 
+NSString *provide_str();
+
 CFMutableArrayRef provide_cf();
 void consume_cf(CFMutableArrayRef);
 
@@ -592,6 +594,10 @@ - (void)doWorkOnSelf {
   [self doWork:@"hello", RetainPtr<SomeObj> { provide() }.get(), RetainPtr<CFMutableArrayRef> { provide_cf() }.get(), OSObjectPtr { provide_dispatch() }.get()];
   [self doWork:__null];
   [self doWork:nil];
+  [provide() isEqual:provide()];
+  [provide_str() isEqualToString:@"foo"];
+  [provide_str() copyWithZone:nullptr];
+  [provide_str() mutableCopy];
 }
 
 - (SomeObj *)getSomeObj {