[analyzer] Add annotation for functions taking user-facing strings

[erikjv]

Summary

There was already a returns_localized_nsstring annotation to indicate
that the return value could be passed to UIKit methods that would
display them. However, those UIKit methods were hard-coded, and it was
not possible to indicate that other classes/methods in a code-base would
do the same.

The takes_localized_nsstring annotation can be put on function
parameters and selector parameters to indicate that those will also show
the string to the user.

[erikjv]

Sorry, now with more context in the diff.

[dcoughlin]

Thanks for the patch! This looks very good to me.

The one thing I would suggest is renaming 'isAnnotatedAsLocalized()' and 'isAnnotatedTakingLocalized()' to make it more clear what each does, now that there are two of them. How about: 'isAnnotatedAsReturningLocalized()' and 'isAnnotatedAsTakingLocalized()'?

lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp

 };
 
 class NonLocalizedStringChecker
-    : public Checker<check::PostCall, check::PreObjCMessage,
+    : public Checker<check::PreCall, check::PostCall, check::PreObjCMessage,
                      check::PostObjCMessage,
                      check::PostStmt<ObjCStringLiteral>> {
 

   void setLocalizedState(SVal S, CheckerContext &C) const;
 
   bool isAnnotatedAsLocalized(const Decl *D) const;
-  void reportLocalizationError(SVal S, const ObjCMethodCall &M,
-                               CheckerContext &C, int argumentNumber = 0) const;
+  bool isAnnotatedTakingLocalized(const Decl *D) const;
+  void reportLocalizationError(SVal S, const CallEvent &M, CheckerContext &C,
+                               int argumentNumber = 0) const;
 
   int getLocalizedArgumentForSelector(const IdentifierInfo *Receiver,
                                       Selector S) const;

   void checkPreObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const;
   void checkPostObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const;
   void checkPostStmt(const ObjCStringLiteral *SL, CheckerContext &C) const;
+  void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
   void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
 };
 

       });
 }
 
+/// Checks to see if the method / function declaration includes
+/// __attribute__((annotate("takes_localized_nsstring")))
+bool NonLocalizedStringChecker::isAnnotatedTakingLocalized(const Decl *D) const {
+  if (!D)
+    return false;
+  return std::any_of(
+      D->specific_attr_begin<AnnotateAttr>(),
+      D->specific_attr_end<AnnotateAttr>(), [](const AnnotateAttr *Ann) {
+        return Ann->getAnnotation() == "takes_localized_nsstring";
+      });
+}
+
 /// Returns true if the given SVal is marked as Localized in the program state
 bool NonLocalizedStringChecker::hasLocalizedState(SVal S,
                                                   CheckerContext &C) const {

 
 /// Reports a localization error for the passed in method call and SVal
 void NonLocalizedStringChecker::reportLocalizationError(
-    SVal S, const ObjCMethodCall &M, CheckerContext &C,
-    int argumentNumber) const {
+    SVal S, const CallEvent &M, CheckerContext &C, int argumentNumber) const {
 
   // Don't warn about localization errors in classes and methods that
   // may be debug code.

     }
   }
 
-  if (argumentNumber < 0) // There was no match in UIMethods
+  if (argumentNumber < 0) { // There was no match in UIMethods
+    if (const Decl *D = msg.getDecl()) {
+      if (const ObjCMethodDecl *OMD = dyn_cast_or_null<ObjCMethodDecl>(D)) {
+        auto formals = OMD->parameters();
+        for (unsigned i = 0, ei = formals.size(); i != ei; ++i) {
+          if (isAnnotatedTakingLocalized(formals[i])) {
+            argumentNumber = i;
+            break;
+          }
+        }
+      }
+    }
+  }
+
+  if (argumentNumber < 0) // Still no match
     return;
 
   SVal svTitle = msg.getArgSVal(argumentNumber);

   }
 }
 
+void NonLocalizedStringChecker::checkPreCall(const CallEvent &Call,
+                                             CheckerContext &C) const {
+  const Decl *D = Call.getDecl();
+  if (D && isa<FunctionDecl>(D)) {
+    const FunctionDecl *FD = dyn_cast<FunctionDecl>(D);
+    auto formals = FD->parameters();
+    for (unsigned i = 0,
+                  ei = std::min(unsigned(formals.size()), Call.getNumArgs());
+         i != ei; ++i) {
+      if (isAnnotatedTakingLocalized(formals[i])) {
+        auto actual = Call.getArgSVal(i);
+        if (hasNonLocalizedState(actual, C)) {
+          reportLocalizationError(actual, Call, C, i + 1);
+        }
+      }
+    }
+  }
+}
+
 static inline bool isNSStringType(QualType T, ASTContext &Ctx) {
 
   const ObjCObjectPointerType *PT = T->getAs<ObjCObjectPointerType>();

test/Analysis/localization-aggressive.m

 NSString *CFNumberFormatterCreateStringWithNumber(float x);
 + (NSString *)forceLocalized:(NSString *)str
     __attribute__((annotate("returns_localized_nsstring")));
++ (NSString *)takesLocalizedString:
+    (NSString *)__attribute__((annotate("takes_localized_nsstring")))str;
 @end
 
+NSString *
+takesLocalizedString(NSString *str
+                     __attribute__((annotate("takes_localized_nsstring")))) {
+  return str;
+}
+
 // Test cases begin here
 @implementation LocalizationTestSuite
 

   return str;
 }
 
++ (NSString *) takesLocalizedString:(NSString *)str { return str; }
+
 // An ObjC method that returns a localized string
 + (NSString *)unLocalizedStringMethod {
   return @"UnlocalizedString";

   NSString *string2 = POSSIBLE_FALSE_POSITIVE(@"Hello", @"Hello"); // no-warning
 }
 
+- (void)testTakesLocalizedString {
+  NSString *localized = NSLocalizedString(@"Hello", @"World");
+  NSString *alsoLocalized = [LocalizationTestSuite takesLocalizedString:localized]; // no-warning
+  NSString *stillLocalized = [LocalizationTestSuite takesLocalizedString:alsoLocalized]; // no-warning
+  takesLocalizedString(stillLocalized); // no-warning
+
+  [LocalizationTestSuite takesLocalizedString:@"not localized"]; // expected-warning {{User-facing text should use localized string macro}}
+  takesLocalizedString(@"not localized"); // expected-warning {{User-facing text should use localized string macro}}
+}
 @end