[Clang] Diagnose additional ObjC statements as function effect violat…

…ions (llvm#112148) Bug fix: `@autoreleasepool`, `@synchronized`, and `@finally` were not being noticed and treated as function effect violations. --------- Co-authored-by: Doug Wyatt <dwyatt@apple.com>
efcs · Oct 22, 2024 · 7cad785 · 7cad785
1 parent 3a7ec30
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diff --git a/clang/lib/Sema/SemaFunctionEffects.cpp b/clang/lib/Sema/SemaFunctionEffects.cpp
@@ -1133,13 +1133,40 @@ class Analyzer {
       return true;
     }
 
+    bool VisitObjCAtFinallyStmt(ObjCAtFinallyStmt *Finally) {
+      diagnoseLanguageConstruct(FunctionEffect::FE_ExcludeCatch,
+                                ViolationID::ThrowsOrCatchesExceptions,
+                                Finally->getAtFinallyLoc());
+      return true;
+    }
+
     bool VisitObjCMessageExpr(ObjCMessageExpr *Msg) {
       diagnoseLanguageConstruct(FunctionEffect::FE_ExcludeObjCMessageSend,
                                 ViolationID::AccessesObjCMethodOrProperty,
                                 Msg->getBeginLoc());
       return true;
     }
 
+    bool VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *ARP) {
+      // Under the hood, @autorelease (potentially?) allocates memory and
+      // invokes ObjC methods. We don't currently have memory allocation as
+      // a "language construct" but we do have ObjC messaging, so diagnose that.
+      diagnoseLanguageConstruct(FunctionEffect::FE_ExcludeObjCMessageSend,
+                                ViolationID::AccessesObjCMethodOrProperty,
+                                ARP->getBeginLoc());
+      return true;
+    }
+
+    bool VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *Sync) {
+      // Under the hood, this calls objc_sync_enter and objc_sync_exit, wrapped
+      // in a @try/@finally block. Diagnose this generically as "ObjC
+      // messaging".
+      diagnoseLanguageConstruct(FunctionEffect::FE_ExcludeObjCMessageSend,
+                                ViolationID::AccessesObjCMethodOrProperty,
+                                Sync->getBeginLoc());
+      return true;
+    }
+
     bool VisitSEHExceptStmt(SEHExceptStmt *Exc) {
       diagnoseLanguageConstruct(FunctionEffect::FE_ExcludeCatch,
                                 ViolationID::ThrowsOrCatchesExceptions,

diff --git a/clang/test/SemaObjCXX/attr-nonblocking-constraints.mm b/clang/test/SemaObjCXX/attr-nonblocking-constraints.mm
@@ -23,4 +23,17 @@ void nb4() [[clang::nonblocking]] {
 	}
 	@catch (...) { // expected-warning {{function with 'nonblocking' attribute must not throw or catch exceptions}}
 	}
+	@finally { // expected-warning {{function with 'nonblocking' attribute must not throw or catch exceptions}}
+	}
+}
+
+@class Lock;
+extern Lock *someLock;
+
+void nb5() [[clang::nonblocking]] {
+	@autoreleasepool { // expected-warning {{function with 'nonblocking' attribute must not access ObjC methods or properties}}
+	}
+
+	@synchronized(someLock) { // expected-warning {{function with 'nonblocking' attribute must not access ObjC methods or properties}}
+	}
 }