[WebKit Checkers] Recognize NSApp as a safe global variable (llvm#160990)

Treat accessing NSApp without retaining it as safe

Author: rniwa

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

@@ -32,9 +32,9 @@ bool tryToFindPtrOrigin(
     if (auto *DRE = dyn_cast<DeclRefExpr>(E)) {
       if (auto *VD = dyn_cast_or_null<VarDecl>(DRE->getDecl())) {
         auto QT = VD->getType();
-        if (VD->hasGlobalStorage() && QT.isConstQualified()) {
+        auto IsImmortal = safeGetName(VD) == "NSApp";
+        if (VD->hasGlobalStorage() && (IsImmortal || QT.isConstQualified()))
           return callback(E, true);
-        }
       }
     }
     if (auto *tempExpr = dyn_cast<MaterializeTemporaryExpr>(E)) {

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

@@ -178,6 +178,22 @@ __attribute__((objc_root_class))
 + (NSNumber *)numberWithBool:(BOOL)value;
 @end
 
+@interface NSResponder : NSObject
+@end
+
+@interface NSApplication : NSResponder
+
+extern NSApplication * NSApp;
+
+@property (class, readonly, strong) NSApplication *sharedApplication;
+
+- (void)finishLaunching;
+- (void)run;
+- (void)stop:(id)sender;
+- (void)terminate:(id)sender;
+
+@end
+
 @interface SomeObj : NSObject
 - (instancetype)_init;
 - (SomeObj *)mutableCopy;

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

@@ -587,6 +587,7 @@ - (void)doWorkOnSelf {
   [self doWork:@"hello", RetainPtr<SomeObj> { provide() }.get(), RetainPtr<CFMutableArrayRef> { provide_cf() }.get(), OSObjectPtr { provide_dispatch() }.get()];
   [self doWork:__null];
   [self doWork:nil];
+  [NSApp run];
 }
 
 - (SomeObj *)getSomeObj {