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

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Ryosuke Niwa (rniwa)

<details>
<summary>Changes</summary>

Treat accessing NSApp without retaining it as safe

---
Full diff: https://github.com/llvm/llvm-project/pull/160990.diff


3 Files Affected:

- (modified) clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp (+2-2) 
- (modified) clang/test/Analysis/Checkers/WebKit/objc-mock-types.h (+16) 
- (modified) clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm (+1) 


``````````diff
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp
index 00a1b8b6e7e895..2e407eb7cf1e9f 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp
@@ -31,9 +31,9 @@ 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)) {
diff --git a/clang/test/Analysis/Checkers/WebKit/objc-mock-types.h b/clang/test/Analysis/Checkers/WebKit/objc-mock-types.h
index 39dee1746158b5..7a199530ca52f3 100644
--- a/clang/test/Analysis/Checkers/WebKit/objc-mock-types.h
+++ b/clang/test/Analysis/Checkers/WebKit/objc-mock-types.h
@@ -163,6 +163,22 @@ __attribute__((objc_root_class))
 + (NSNumber *)numberWithBool:(BOOL)value;
 @end
 
+ at interface NSResponder : NSObject
+ at end
+
+ at interface NSApplication : NSResponder
+
+extern NSApplication * NSApp;
+
+ at property (class, readonly, strong) NSApplication *sharedApplication;
+
+- (void)finishLaunching;
+- (void)run;
+- (void)stop:(id)sender;
+- (void)terminate:(id)sender;
+
+ at end
+
 @interface SomeObj : NSObject
 - (instancetype)_init;
 - (SomeObj *)mutableCopy;
diff --git a/clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm b/clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm
index c9d2fe861bb498..03ef200fb51f58 100644
--- a/clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm
+++ b/clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm
@@ -582,6 +582,7 @@ - (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 {

``````````

</details>


https://github.com/llvm/llvm-project/pull/160990