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      1 //=- LocalizationChecker.cpp -------------------------------------*- C++ -*-==//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 //  This file defines a set of checks for localizability including:
     11 //  1) A checker that warns about uses of non-localized NSStrings passed to
     12 //     UI methods expecting localized strings
     13 //  2) A syntactic checker that warns against the bad practice of
     14 //     not including a comment in NSLocalizedString macros.
     15 //
     16 //===----------------------------------------------------------------------===//
     17 
     18 #include "ClangSACheckers.h"
     19 #include "clang/AST/Attr.h"
     20 #include "clang/AST/Decl.h"
     21 #include "clang/AST/DeclObjC.h"
     22 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
     23 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
     24 #include "clang/StaticAnalyzer/Core/Checker.h"
     25 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
     26 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
     27 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
     28 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
     29 #include "clang/Lex/Lexer.h"
     30 #include "clang/AST/RecursiveASTVisitor.h"
     31 #include "clang/AST/StmtVisitor.h"
     32 #include "llvm/Support/Unicode.h"
     33 #include "llvm/ADT/StringSet.h"
     34 
     35 using namespace clang;
     36 using namespace ento;
     37 
     38 namespace {
     39 struct LocalizedState {
     40 private:
     41   enum Kind { NonLocalized, Localized } K;
     42   LocalizedState(Kind InK) : K(InK) {}
     43 
     44 public:
     45   bool isLocalized() const { return K == Localized; }
     46   bool isNonLocalized() const { return K == NonLocalized; }
     47 
     48   static LocalizedState getLocalized() { return LocalizedState(Localized); }
     49   static LocalizedState getNonLocalized() {
     50     return LocalizedState(NonLocalized);
     51   }
     52 
     53   // Overload the == operator
     54   bool operator==(const LocalizedState &X) const { return K == X.K; }
     55 
     56   // LLVMs equivalent of a hash function
     57   void Profile(llvm::FoldingSetNodeID &ID) const { ID.AddInteger(K); }
     58 };
     59 
     60 class NonLocalizedStringChecker
     61     : public Checker<check::PostCall, check::PreObjCMessage,
     62                      check::PostObjCMessage,
     63                      check::PostStmt<ObjCStringLiteral>> {
     64 
     65   mutable std::unique_ptr<BugType> BT;
     66 
     67   // Methods that require a localized string
     68   mutable llvm::DenseMap<const IdentifierInfo *,
     69                          llvm::DenseMap<Selector, uint8_t>> UIMethods;
     70   // Methods that return a localized string
     71   mutable llvm::SmallSet<std::pair<const IdentifierInfo *, Selector>, 12> LSM;
     72   // C Functions that return a localized string
     73   mutable llvm::SmallSet<const IdentifierInfo *, 5> LSF;
     74 
     75   void initUIMethods(ASTContext &Ctx) const;
     76   void initLocStringsMethods(ASTContext &Ctx) const;
     77 
     78   bool hasNonLocalizedState(SVal S, CheckerContext &C) const;
     79   bool hasLocalizedState(SVal S, CheckerContext &C) const;
     80   void setNonLocalizedState(SVal S, CheckerContext &C) const;
     81   void setLocalizedState(SVal S, CheckerContext &C) const;
     82 
     83   bool isAnnotatedAsLocalized(const Decl *D) const;
     84   void reportLocalizationError(SVal S, const ObjCMethodCall &M,
     85                                CheckerContext &C, int argumentNumber = 0) const;
     86 
     87   int getLocalizedArgumentForSelector(const IdentifierInfo *Receiver,
     88                                       Selector S) const;
     89 
     90 public:
     91   NonLocalizedStringChecker();
     92 
     93   // When this parameter is set to true, the checker assumes all
     94   // methods that return NSStrings are unlocalized. Thus, more false
     95   // positives will be reported.
     96   DefaultBool IsAggressive;
     97 
     98   void checkPreObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const;
     99   void checkPostObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const;
    100   void checkPostStmt(const ObjCStringLiteral *SL, CheckerContext &C) const;
    101   void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
    102 };
    103 
    104 } // end anonymous namespace
    105 
    106 REGISTER_MAP_WITH_PROGRAMSTATE(LocalizedMemMap, const MemRegion *,
    107                                LocalizedState)
    108 
    109 NonLocalizedStringChecker::NonLocalizedStringChecker() {
    110   BT.reset(new BugType(this, "Unlocalizable string",
    111                        "Localizability Issue (Apple)"));
    112 }
    113 
    114 #define NEW_RECEIVER(receiver)                                                 \
    115   llvm::DenseMap<Selector, uint8_t> &receiver##M =                             \
    116       UIMethods.insert({&Ctx.Idents.get(#receiver),                            \
    117                         llvm::DenseMap<Selector, uint8_t>()})                  \
    118           .first->second;
    119 #define ADD_NULLARY_METHOD(receiver, method, argument)                         \
    120   receiver##M.insert(                                                          \
    121       {Ctx.Selectors.getNullarySelector(&Ctx.Idents.get(#method)), argument});
    122 #define ADD_UNARY_METHOD(receiver, method, argument)                           \
    123   receiver##M.insert(                                                          \
    124       {Ctx.Selectors.getUnarySelector(&Ctx.Idents.get(#method)), argument});
    125 #define ADD_METHOD(receiver, method_list, count, argument)                     \
    126   receiver##M.insert({Ctx.Selectors.getSelector(count, method_list), argument});
    127 
    128 /// Initializes a list of methods that require a localized string
    129 /// Format: {"ClassName", {{"selectorName:", LocStringArg#}, ...}, ...}
    130 void NonLocalizedStringChecker::initUIMethods(ASTContext &Ctx) const {
    131   if (!UIMethods.empty())
    132     return;
    133 
    134   // UI Methods
    135   NEW_RECEIVER(UISearchDisplayController)
    136   ADD_UNARY_METHOD(UISearchDisplayController, setSearchResultsTitle, 0)
    137 
    138   NEW_RECEIVER(UITabBarItem)
    139   IdentifierInfo *initWithTitleUITabBarItemTag[] = {
    140       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("image"),
    141       &Ctx.Idents.get("tag")};
    142   ADD_METHOD(UITabBarItem, initWithTitleUITabBarItemTag, 3, 0)
    143   IdentifierInfo *initWithTitleUITabBarItemImage[] = {
    144       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("image"),
    145       &Ctx.Idents.get("selectedImage")};
    146   ADD_METHOD(UITabBarItem, initWithTitleUITabBarItemImage, 3, 0)
    147 
    148   NEW_RECEIVER(NSDockTile)
    149   ADD_UNARY_METHOD(NSDockTile, setBadgeLabel, 0)
    150 
    151   NEW_RECEIVER(NSStatusItem)
    152   ADD_UNARY_METHOD(NSStatusItem, setTitle, 0)
    153   ADD_UNARY_METHOD(NSStatusItem, setToolTip, 0)
    154 
    155   NEW_RECEIVER(UITableViewRowAction)
    156   IdentifierInfo *rowActionWithStyleUITableViewRowAction[] = {
    157       &Ctx.Idents.get("rowActionWithStyle"), &Ctx.Idents.get("title"),
    158       &Ctx.Idents.get("handler")};
    159   ADD_METHOD(UITableViewRowAction, rowActionWithStyleUITableViewRowAction, 3, 1)
    160   ADD_UNARY_METHOD(UITableViewRowAction, setTitle, 0)
    161 
    162   NEW_RECEIVER(NSBox)
    163   ADD_UNARY_METHOD(NSBox, setTitle, 0)
    164 
    165   NEW_RECEIVER(NSButton)
    166   ADD_UNARY_METHOD(NSButton, setTitle, 0)
    167   ADD_UNARY_METHOD(NSButton, setAlternateTitle, 0)
    168 
    169   NEW_RECEIVER(NSSavePanel)
    170   ADD_UNARY_METHOD(NSSavePanel, setPrompt, 0)
    171   ADD_UNARY_METHOD(NSSavePanel, setTitle, 0)
    172   ADD_UNARY_METHOD(NSSavePanel, setNameFieldLabel, 0)
    173   ADD_UNARY_METHOD(NSSavePanel, setNameFieldStringValue, 0)
    174   ADD_UNARY_METHOD(NSSavePanel, setMessage, 0)
    175 
    176   NEW_RECEIVER(UIPrintInfo)
    177   ADD_UNARY_METHOD(UIPrintInfo, setJobName, 0)
    178 
    179   NEW_RECEIVER(NSTabViewItem)
    180   ADD_UNARY_METHOD(NSTabViewItem, setLabel, 0)
    181   ADD_UNARY_METHOD(NSTabViewItem, setToolTip, 0)
    182 
    183   NEW_RECEIVER(NSBrowser)
    184   IdentifierInfo *setTitleNSBrowser[] = {&Ctx.Idents.get("setTitle"),
    185                                          &Ctx.Idents.get("ofColumn")};
    186   ADD_METHOD(NSBrowser, setTitleNSBrowser, 2, 0)
    187 
    188   NEW_RECEIVER(UIAccessibilityElement)
    189   ADD_UNARY_METHOD(UIAccessibilityElement, setAccessibilityLabel, 0)
    190   ADD_UNARY_METHOD(UIAccessibilityElement, setAccessibilityHint, 0)
    191   ADD_UNARY_METHOD(UIAccessibilityElement, setAccessibilityValue, 0)
    192 
    193   NEW_RECEIVER(UIAlertAction)
    194   IdentifierInfo *actionWithTitleUIAlertAction[] = {
    195       &Ctx.Idents.get("actionWithTitle"), &Ctx.Idents.get("style"),
    196       &Ctx.Idents.get("handler")};
    197   ADD_METHOD(UIAlertAction, actionWithTitleUIAlertAction, 3, 0)
    198 
    199   NEW_RECEIVER(NSPopUpButton)
    200   ADD_UNARY_METHOD(NSPopUpButton, addItemWithTitle, 0)
    201   IdentifierInfo *insertItemWithTitleNSPopUpButton[] = {
    202       &Ctx.Idents.get("insertItemWithTitle"), &Ctx.Idents.get("atIndex")};
    203   ADD_METHOD(NSPopUpButton, insertItemWithTitleNSPopUpButton, 2, 0)
    204   ADD_UNARY_METHOD(NSPopUpButton, removeItemWithTitle, 0)
    205   ADD_UNARY_METHOD(NSPopUpButton, selectItemWithTitle, 0)
    206   ADD_UNARY_METHOD(NSPopUpButton, setTitle, 0)
    207 
    208   NEW_RECEIVER(NSTableViewRowAction)
    209   IdentifierInfo *rowActionWithStyleNSTableViewRowAction[] = {
    210       &Ctx.Idents.get("rowActionWithStyle"), &Ctx.Idents.get("title"),
    211       &Ctx.Idents.get("handler")};
    212   ADD_METHOD(NSTableViewRowAction, rowActionWithStyleNSTableViewRowAction, 3, 1)
    213   ADD_UNARY_METHOD(NSTableViewRowAction, setTitle, 0)
    214 
    215   NEW_RECEIVER(NSImage)
    216   ADD_UNARY_METHOD(NSImage, setAccessibilityDescription, 0)
    217 
    218   NEW_RECEIVER(NSUserActivity)
    219   ADD_UNARY_METHOD(NSUserActivity, setTitle, 0)
    220 
    221   NEW_RECEIVER(NSPathControlItem)
    222   ADD_UNARY_METHOD(NSPathControlItem, setTitle, 0)
    223 
    224   NEW_RECEIVER(NSCell)
    225   ADD_UNARY_METHOD(NSCell, initTextCell, 0)
    226   ADD_UNARY_METHOD(NSCell, setTitle, 0)
    227   ADD_UNARY_METHOD(NSCell, setStringValue, 0)
    228 
    229   NEW_RECEIVER(NSPathControl)
    230   ADD_UNARY_METHOD(NSPathControl, setPlaceholderString, 0)
    231 
    232   NEW_RECEIVER(UIAccessibility)
    233   ADD_UNARY_METHOD(UIAccessibility, setAccessibilityLabel, 0)
    234   ADD_UNARY_METHOD(UIAccessibility, setAccessibilityHint, 0)
    235   ADD_UNARY_METHOD(UIAccessibility, setAccessibilityValue, 0)
    236 
    237   NEW_RECEIVER(NSTableColumn)
    238   ADD_UNARY_METHOD(NSTableColumn, setTitle, 0)
    239   ADD_UNARY_METHOD(NSTableColumn, setHeaderToolTip, 0)
    240 
    241   NEW_RECEIVER(NSSegmentedControl)
    242   IdentifierInfo *setLabelNSSegmentedControl[] = {
    243       &Ctx.Idents.get("setLabel"), &Ctx.Idents.get("forSegment")};
    244   ADD_METHOD(NSSegmentedControl, setLabelNSSegmentedControl, 2, 0)
    245 
    246   NEW_RECEIVER(NSButtonCell)
    247   ADD_UNARY_METHOD(NSButtonCell, setTitle, 0)
    248   ADD_UNARY_METHOD(NSButtonCell, setAlternateTitle, 0)
    249 
    250   NEW_RECEIVER(NSSliderCell)
    251   ADD_UNARY_METHOD(NSSliderCell, setTitle, 0)
    252 
    253   NEW_RECEIVER(NSControl)
    254   ADD_UNARY_METHOD(NSControl, setStringValue, 0)
    255 
    256   NEW_RECEIVER(NSAccessibility)
    257   ADD_UNARY_METHOD(NSAccessibility, setAccessibilityValueDescription, 0)
    258   ADD_UNARY_METHOD(NSAccessibility, setAccessibilityLabel, 0)
    259   ADD_UNARY_METHOD(NSAccessibility, setAccessibilityTitle, 0)
    260   ADD_UNARY_METHOD(NSAccessibility, setAccessibilityPlaceholderValue, 0)
    261   ADD_UNARY_METHOD(NSAccessibility, setAccessibilityHelp, 0)
    262 
    263   NEW_RECEIVER(NSMatrix)
    264   IdentifierInfo *setToolTipNSMatrix[] = {&Ctx.Idents.get("setToolTip"),
    265                                           &Ctx.Idents.get("forCell")};
    266   ADD_METHOD(NSMatrix, setToolTipNSMatrix, 2, 0)
    267 
    268   NEW_RECEIVER(NSPrintPanel)
    269   ADD_UNARY_METHOD(NSPrintPanel, setDefaultButtonTitle, 0)
    270 
    271   NEW_RECEIVER(UILocalNotification)
    272   ADD_UNARY_METHOD(UILocalNotification, setAlertBody, 0)
    273   ADD_UNARY_METHOD(UILocalNotification, setAlertAction, 0)
    274   ADD_UNARY_METHOD(UILocalNotification, setAlertTitle, 0)
    275 
    276   NEW_RECEIVER(NSSlider)
    277   ADD_UNARY_METHOD(NSSlider, setTitle, 0)
    278 
    279   NEW_RECEIVER(UIMenuItem)
    280   IdentifierInfo *initWithTitleUIMenuItem[] = {&Ctx.Idents.get("initWithTitle"),
    281                                                &Ctx.Idents.get("action")};
    282   ADD_METHOD(UIMenuItem, initWithTitleUIMenuItem, 2, 0)
    283   ADD_UNARY_METHOD(UIMenuItem, setTitle, 0)
    284 
    285   NEW_RECEIVER(UIAlertController)
    286   IdentifierInfo *alertControllerWithTitleUIAlertController[] = {
    287       &Ctx.Idents.get("alertControllerWithTitle"), &Ctx.Idents.get("message"),
    288       &Ctx.Idents.get("preferredStyle")};
    289   ADD_METHOD(UIAlertController, alertControllerWithTitleUIAlertController, 3, 1)
    290   ADD_UNARY_METHOD(UIAlertController, setTitle, 0)
    291   ADD_UNARY_METHOD(UIAlertController, setMessage, 0)
    292 
    293   NEW_RECEIVER(UIApplicationShortcutItem)
    294   IdentifierInfo *initWithTypeUIApplicationShortcutItemIcon[] = {
    295       &Ctx.Idents.get("initWithType"), &Ctx.Idents.get("localizedTitle"),
    296       &Ctx.Idents.get("localizedSubtitle"), &Ctx.Idents.get("icon"),
    297       &Ctx.Idents.get("userInfo")};
    298   ADD_METHOD(UIApplicationShortcutItem,
    299              initWithTypeUIApplicationShortcutItemIcon, 5, 1)
    300   IdentifierInfo *initWithTypeUIApplicationShortcutItem[] = {
    301       &Ctx.Idents.get("initWithType"), &Ctx.Idents.get("localizedTitle")};
    302   ADD_METHOD(UIApplicationShortcutItem, initWithTypeUIApplicationShortcutItem,
    303              2, 1)
    304 
    305   NEW_RECEIVER(UIActionSheet)
    306   IdentifierInfo *initWithTitleUIActionSheet[] = {
    307       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("delegate"),
    308       &Ctx.Idents.get("cancelButtonTitle"),
    309       &Ctx.Idents.get("destructiveButtonTitle"),
    310       &Ctx.Idents.get("otherButtonTitles")};
    311   ADD_METHOD(UIActionSheet, initWithTitleUIActionSheet, 5, 0)
    312   ADD_UNARY_METHOD(UIActionSheet, addButtonWithTitle, 0)
    313   ADD_UNARY_METHOD(UIActionSheet, setTitle, 0)
    314 
    315   NEW_RECEIVER(NSURLSessionTask)
    316   ADD_UNARY_METHOD(NSURLSessionTask, setTaskDescription, 0)
    317 
    318   NEW_RECEIVER(UIAccessibilityCustomAction)
    319   IdentifierInfo *initWithNameUIAccessibilityCustomAction[] = {
    320       &Ctx.Idents.get("initWithName"), &Ctx.Idents.get("target"),
    321       &Ctx.Idents.get("selector")};
    322   ADD_METHOD(UIAccessibilityCustomAction,
    323              initWithNameUIAccessibilityCustomAction, 3, 0)
    324   ADD_UNARY_METHOD(UIAccessibilityCustomAction, setName, 0)
    325 
    326   NEW_RECEIVER(UISearchBar)
    327   ADD_UNARY_METHOD(UISearchBar, setText, 0)
    328   ADD_UNARY_METHOD(UISearchBar, setPrompt, 0)
    329   ADD_UNARY_METHOD(UISearchBar, setPlaceholder, 0)
    330 
    331   NEW_RECEIVER(UIBarItem)
    332   ADD_UNARY_METHOD(UIBarItem, setTitle, 0)
    333 
    334   NEW_RECEIVER(UITextView)
    335   ADD_UNARY_METHOD(UITextView, setText, 0)
    336 
    337   NEW_RECEIVER(NSView)
    338   ADD_UNARY_METHOD(NSView, setToolTip, 0)
    339 
    340   NEW_RECEIVER(NSTextField)
    341   ADD_UNARY_METHOD(NSTextField, setPlaceholderString, 0)
    342 
    343   NEW_RECEIVER(NSAttributedString)
    344   ADD_UNARY_METHOD(NSAttributedString, initWithString, 0)
    345   IdentifierInfo *initWithStringNSAttributedString[] = {
    346       &Ctx.Idents.get("initWithString"), &Ctx.Idents.get("attributes")};
    347   ADD_METHOD(NSAttributedString, initWithStringNSAttributedString, 2, 0)
    348 
    349   NEW_RECEIVER(NSText)
    350   ADD_UNARY_METHOD(NSText, setString, 0)
    351 
    352   NEW_RECEIVER(UIKeyCommand)
    353   IdentifierInfo *keyCommandWithInputUIKeyCommand[] = {
    354       &Ctx.Idents.get("keyCommandWithInput"), &Ctx.Idents.get("modifierFlags"),
    355       &Ctx.Idents.get("action"), &Ctx.Idents.get("discoverabilityTitle")};
    356   ADD_METHOD(UIKeyCommand, keyCommandWithInputUIKeyCommand, 4, 3)
    357   ADD_UNARY_METHOD(UIKeyCommand, setDiscoverabilityTitle, 0)
    358 
    359   NEW_RECEIVER(UILabel)
    360   ADD_UNARY_METHOD(UILabel, setText, 0)
    361 
    362   NEW_RECEIVER(NSAlert)
    363   IdentifierInfo *alertWithMessageTextNSAlert[] = {
    364       &Ctx.Idents.get("alertWithMessageText"), &Ctx.Idents.get("defaultButton"),
    365       &Ctx.Idents.get("alternateButton"), &Ctx.Idents.get("otherButton"),
    366       &Ctx.Idents.get("informativeTextWithFormat")};
    367   ADD_METHOD(NSAlert, alertWithMessageTextNSAlert, 5, 0)
    368   ADD_UNARY_METHOD(NSAlert, addButtonWithTitle, 0)
    369   ADD_UNARY_METHOD(NSAlert, setMessageText, 0)
    370   ADD_UNARY_METHOD(NSAlert, setInformativeText, 0)
    371   ADD_UNARY_METHOD(NSAlert, setHelpAnchor, 0)
    372 
    373   NEW_RECEIVER(UIMutableApplicationShortcutItem)
    374   ADD_UNARY_METHOD(UIMutableApplicationShortcutItem, setLocalizedTitle, 0)
    375   ADD_UNARY_METHOD(UIMutableApplicationShortcutItem, setLocalizedSubtitle, 0)
    376 
    377   NEW_RECEIVER(UIButton)
    378   IdentifierInfo *setTitleUIButton[] = {&Ctx.Idents.get("setTitle"),
    379                                         &Ctx.Idents.get("forState")};
    380   ADD_METHOD(UIButton, setTitleUIButton, 2, 0)
    381 
    382   NEW_RECEIVER(NSWindow)
    383   ADD_UNARY_METHOD(NSWindow, setTitle, 0)
    384   IdentifierInfo *minFrameWidthWithTitleNSWindow[] = {
    385       &Ctx.Idents.get("minFrameWidthWithTitle"), &Ctx.Idents.get("styleMask")};
    386   ADD_METHOD(NSWindow, minFrameWidthWithTitleNSWindow, 2, 0)
    387   ADD_UNARY_METHOD(NSWindow, setMiniwindowTitle, 0)
    388 
    389   NEW_RECEIVER(NSPathCell)
    390   ADD_UNARY_METHOD(NSPathCell, setPlaceholderString, 0)
    391 
    392   NEW_RECEIVER(UIDocumentMenuViewController)
    393   IdentifierInfo *addOptionWithTitleUIDocumentMenuViewController[] = {
    394       &Ctx.Idents.get("addOptionWithTitle"), &Ctx.Idents.get("image"),
    395       &Ctx.Idents.get("order"), &Ctx.Idents.get("handler")};
    396   ADD_METHOD(UIDocumentMenuViewController,
    397              addOptionWithTitleUIDocumentMenuViewController, 4, 0)
    398 
    399   NEW_RECEIVER(UINavigationItem)
    400   ADD_UNARY_METHOD(UINavigationItem, initWithTitle, 0)
    401   ADD_UNARY_METHOD(UINavigationItem, setTitle, 0)
    402   ADD_UNARY_METHOD(UINavigationItem, setPrompt, 0)
    403 
    404   NEW_RECEIVER(UIAlertView)
    405   IdentifierInfo *initWithTitleUIAlertView[] = {
    406       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("message"),
    407       &Ctx.Idents.get("delegate"), &Ctx.Idents.get("cancelButtonTitle"),
    408       &Ctx.Idents.get("otherButtonTitles")};
    409   ADD_METHOD(UIAlertView, initWithTitleUIAlertView, 5, 0)
    410   ADD_UNARY_METHOD(UIAlertView, addButtonWithTitle, 0)
    411   ADD_UNARY_METHOD(UIAlertView, setTitle, 0)
    412   ADD_UNARY_METHOD(UIAlertView, setMessage, 0)
    413 
    414   NEW_RECEIVER(NSFormCell)
    415   ADD_UNARY_METHOD(NSFormCell, initTextCell, 0)
    416   ADD_UNARY_METHOD(NSFormCell, setTitle, 0)
    417   ADD_UNARY_METHOD(NSFormCell, setPlaceholderString, 0)
    418 
    419   NEW_RECEIVER(NSUserNotification)
    420   ADD_UNARY_METHOD(NSUserNotification, setTitle, 0)
    421   ADD_UNARY_METHOD(NSUserNotification, setSubtitle, 0)
    422   ADD_UNARY_METHOD(NSUserNotification, setInformativeText, 0)
    423   ADD_UNARY_METHOD(NSUserNotification, setActionButtonTitle, 0)
    424   ADD_UNARY_METHOD(NSUserNotification, setOtherButtonTitle, 0)
    425   ADD_UNARY_METHOD(NSUserNotification, setResponsePlaceholder, 0)
    426 
    427   NEW_RECEIVER(NSToolbarItem)
    428   ADD_UNARY_METHOD(NSToolbarItem, setLabel, 0)
    429   ADD_UNARY_METHOD(NSToolbarItem, setPaletteLabel, 0)
    430   ADD_UNARY_METHOD(NSToolbarItem, setToolTip, 0)
    431 
    432   NEW_RECEIVER(NSProgress)
    433   ADD_UNARY_METHOD(NSProgress, setLocalizedDescription, 0)
    434   ADD_UNARY_METHOD(NSProgress, setLocalizedAdditionalDescription, 0)
    435 
    436   NEW_RECEIVER(NSSegmentedCell)
    437   IdentifierInfo *setLabelNSSegmentedCell[] = {&Ctx.Idents.get("setLabel"),
    438                                                &Ctx.Idents.get("forSegment")};
    439   ADD_METHOD(NSSegmentedCell, setLabelNSSegmentedCell, 2, 0)
    440   IdentifierInfo *setToolTipNSSegmentedCell[] = {&Ctx.Idents.get("setToolTip"),
    441                                                  &Ctx.Idents.get("forSegment")};
    442   ADD_METHOD(NSSegmentedCell, setToolTipNSSegmentedCell, 2, 0)
    443 
    444   NEW_RECEIVER(NSUndoManager)
    445   ADD_UNARY_METHOD(NSUndoManager, setActionName, 0)
    446   ADD_UNARY_METHOD(NSUndoManager, undoMenuTitleForUndoActionName, 0)
    447   ADD_UNARY_METHOD(NSUndoManager, redoMenuTitleForUndoActionName, 0)
    448 
    449   NEW_RECEIVER(NSMenuItem)
    450   IdentifierInfo *initWithTitleNSMenuItem[] = {
    451       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("action"),
    452       &Ctx.Idents.get("keyEquivalent")};
    453   ADD_METHOD(NSMenuItem, initWithTitleNSMenuItem, 3, 0)
    454   ADD_UNARY_METHOD(NSMenuItem, setTitle, 0)
    455   ADD_UNARY_METHOD(NSMenuItem, setToolTip, 0)
    456 
    457   NEW_RECEIVER(NSPopUpButtonCell)
    458   IdentifierInfo *initTextCellNSPopUpButtonCell[] = {
    459       &Ctx.Idents.get("initTextCell"), &Ctx.Idents.get("pullsDown")};
    460   ADD_METHOD(NSPopUpButtonCell, initTextCellNSPopUpButtonCell, 2, 0)
    461   ADD_UNARY_METHOD(NSPopUpButtonCell, addItemWithTitle, 0)
    462   IdentifierInfo *insertItemWithTitleNSPopUpButtonCell[] = {
    463       &Ctx.Idents.get("insertItemWithTitle"), &Ctx.Idents.get("atIndex")};
    464   ADD_METHOD(NSPopUpButtonCell, insertItemWithTitleNSPopUpButtonCell, 2, 0)
    465   ADD_UNARY_METHOD(NSPopUpButtonCell, removeItemWithTitle, 0)
    466   ADD_UNARY_METHOD(NSPopUpButtonCell, selectItemWithTitle, 0)
    467   ADD_UNARY_METHOD(NSPopUpButtonCell, setTitle, 0)
    468 
    469   NEW_RECEIVER(NSViewController)
    470   ADD_UNARY_METHOD(NSViewController, setTitle, 0)
    471 
    472   NEW_RECEIVER(NSMenu)
    473   ADD_UNARY_METHOD(NSMenu, initWithTitle, 0)
    474   IdentifierInfo *insertItemWithTitleNSMenu[] = {
    475       &Ctx.Idents.get("insertItemWithTitle"), &Ctx.Idents.get("action"),
    476       &Ctx.Idents.get("keyEquivalent"), &Ctx.Idents.get("atIndex")};
    477   ADD_METHOD(NSMenu, insertItemWithTitleNSMenu, 4, 0)
    478   IdentifierInfo *addItemWithTitleNSMenu[] = {
    479       &Ctx.Idents.get("addItemWithTitle"), &Ctx.Idents.get("action"),
    480       &Ctx.Idents.get("keyEquivalent")};
    481   ADD_METHOD(NSMenu, addItemWithTitleNSMenu, 3, 0)
    482   ADD_UNARY_METHOD(NSMenu, setTitle, 0)
    483 
    484   NEW_RECEIVER(UIMutableUserNotificationAction)
    485   ADD_UNARY_METHOD(UIMutableUserNotificationAction, setTitle, 0)
    486 
    487   NEW_RECEIVER(NSForm)
    488   ADD_UNARY_METHOD(NSForm, addEntry, 0)
    489   IdentifierInfo *insertEntryNSForm[] = {&Ctx.Idents.get("insertEntry"),
    490                                          &Ctx.Idents.get("atIndex")};
    491   ADD_METHOD(NSForm, insertEntryNSForm, 2, 0)
    492 
    493   NEW_RECEIVER(NSTextFieldCell)
    494   ADD_UNARY_METHOD(NSTextFieldCell, setPlaceholderString, 0)
    495 
    496   NEW_RECEIVER(NSUserNotificationAction)
    497   IdentifierInfo *actionWithIdentifierNSUserNotificationAction[] = {
    498       &Ctx.Idents.get("actionWithIdentifier"), &Ctx.Idents.get("title")};
    499   ADD_METHOD(NSUserNotificationAction,
    500              actionWithIdentifierNSUserNotificationAction, 2, 1)
    501 
    502   NEW_RECEIVER(NSURLSession)
    503   ADD_UNARY_METHOD(NSURLSession, setSessionDescription, 0)
    504 
    505   NEW_RECEIVER(UITextField)
    506   ADD_UNARY_METHOD(UITextField, setText, 0)
    507   ADD_UNARY_METHOD(UITextField, setPlaceholder, 0)
    508 
    509   NEW_RECEIVER(UIBarButtonItem)
    510   IdentifierInfo *initWithTitleUIBarButtonItem[] = {
    511       &Ctx.Idents.get("initWithTitle"), &Ctx.Idents.get("style"),
    512       &Ctx.Idents.get("target"), &Ctx.Idents.get("action")};
    513   ADD_METHOD(UIBarButtonItem, initWithTitleUIBarButtonItem, 4, 0)
    514 
    515   NEW_RECEIVER(UIViewController)
    516   ADD_UNARY_METHOD(UIViewController, setTitle, 0)
    517 
    518   NEW_RECEIVER(UISegmentedControl)
    519   IdentifierInfo *insertSegmentWithTitleUISegmentedControl[] = {
    520       &Ctx.Idents.get("insertSegmentWithTitle"), &Ctx.Idents.get("atIndex"),
    521       &Ctx.Idents.get("animated")};
    522   ADD_METHOD(UISegmentedControl, insertSegmentWithTitleUISegmentedControl, 3, 0)
    523   IdentifierInfo *setTitleUISegmentedControl[] = {
    524       &Ctx.Idents.get("setTitle"), &Ctx.Idents.get("forSegmentAtIndex")};
    525   ADD_METHOD(UISegmentedControl, setTitleUISegmentedControl, 2, 0)
    526 }
    527 
    528 #define LSF_INSERT(function_name) LSF.insert(&Ctx.Idents.get(function_name));
    529 #define LSM_INSERT_NULLARY(receiver, method_name)                              \
    530   LSM.insert({&Ctx.Idents.get(receiver), Ctx.Selectors.getNullarySelector(     \
    531                                              &Ctx.Idents.get(method_name))});
    532 #define LSM_INSERT_UNARY(receiver, method_name)                                \
    533   LSM.insert({&Ctx.Idents.get(receiver),                                       \
    534               Ctx.Selectors.getUnarySelector(&Ctx.Idents.get(method_name))});
    535 #define LSM_INSERT_SELECTOR(receiver, method_list, arguments)                  \
    536   LSM.insert({&Ctx.Idents.get(receiver),                                       \
    537               Ctx.Selectors.getSelector(arguments, method_list)});
    538 
    539 /// Initializes a list of methods and C functions that return a localized string
    540 void NonLocalizedStringChecker::initLocStringsMethods(ASTContext &Ctx) const {
    541   if (!LSM.empty())
    542     return;
    543 
    544   IdentifierInfo *LocalizedStringMacro[] = {
    545       &Ctx.Idents.get("localizedStringForKey"), &Ctx.Idents.get("value"),
    546       &Ctx.Idents.get("table")};
    547   LSM_INSERT_SELECTOR("NSBundle", LocalizedStringMacro, 3)
    548   LSM_INSERT_UNARY("NSDateFormatter", "stringFromDate")
    549   IdentifierInfo *LocalizedStringFromDate[] = {
    550       &Ctx.Idents.get("localizedStringFromDate"), &Ctx.Idents.get("dateStyle"),
    551       &Ctx.Idents.get("timeStyle")};
    552   LSM_INSERT_SELECTOR("NSDateFormatter", LocalizedStringFromDate, 3)
    553   LSM_INSERT_UNARY("NSNumberFormatter", "stringFromNumber")
    554   LSM_INSERT_NULLARY("UITextField", "text")
    555   LSM_INSERT_NULLARY("UITextView", "text")
    556   LSM_INSERT_NULLARY("UILabel", "text")
    557 
    558   LSF_INSERT("CFDateFormatterCreateStringWithDate");
    559   LSF_INSERT("CFDateFormatterCreateStringWithAbsoluteTime");
    560   LSF_INSERT("CFNumberFormatterCreateStringWithNumber");
    561 }
    562 
    563 /// Checks to see if the method / function declaration includes
    564 /// __attribute__((annotate("returns_localized_nsstring")))
    565 bool NonLocalizedStringChecker::isAnnotatedAsLocalized(const Decl *D) const {
    566   if (!D)
    567     return false;
    568   return std::any_of(
    569       D->specific_attr_begin<AnnotateAttr>(),
    570       D->specific_attr_end<AnnotateAttr>(), [](const AnnotateAttr *Ann) {
    571         return Ann->getAnnotation() == "returns_localized_nsstring";
    572       });
    573 }
    574 
    575 /// Returns true if the given SVal is marked as Localized in the program state
    576 bool NonLocalizedStringChecker::hasLocalizedState(SVal S,
    577                                                   CheckerContext &C) const {
    578   const MemRegion *mt = S.getAsRegion();
    579   if (mt) {
    580     const LocalizedState *LS = C.getState()->get<LocalizedMemMap>(mt);
    581     if (LS && LS->isLocalized())
    582       return true;
    583   }
    584   return false;
    585 }
    586 
    587 /// Returns true if the given SVal is marked as NonLocalized in the program
    588 /// state
    589 bool NonLocalizedStringChecker::hasNonLocalizedState(SVal S,
    590                                                      CheckerContext &C) const {
    591   const MemRegion *mt = S.getAsRegion();
    592   if (mt) {
    593     const LocalizedState *LS = C.getState()->get<LocalizedMemMap>(mt);
    594     if (LS && LS->isNonLocalized())
    595       return true;
    596   }
    597   return false;
    598 }
    599 
    600 /// Marks the given SVal as Localized in the program state
    601 void NonLocalizedStringChecker::setLocalizedState(const SVal S,
    602                                                   CheckerContext &C) const {
    603   const MemRegion *mt = S.getAsRegion();
    604   if (mt) {
    605     ProgramStateRef State =
    606         C.getState()->set<LocalizedMemMap>(mt, LocalizedState::getLocalized());
    607     C.addTransition(State);
    608   }
    609 }
    610 
    611 /// Marks the given SVal as NonLocalized in the program state
    612 void NonLocalizedStringChecker::setNonLocalizedState(const SVal S,
    613                                                      CheckerContext &C) const {
    614   const MemRegion *mt = S.getAsRegion();
    615   if (mt) {
    616     ProgramStateRef State = C.getState()->set<LocalizedMemMap>(
    617         mt, LocalizedState::getNonLocalized());
    618     C.addTransition(State);
    619   }
    620 }
    621 
    622 /// Reports a localization error for the passed in method call and SVal
    623 void NonLocalizedStringChecker::reportLocalizationError(
    624     SVal S, const ObjCMethodCall &M, CheckerContext &C,
    625     int argumentNumber) const {
    626 
    627   ExplodedNode *ErrNode = C.getPredecessor();
    628   static CheckerProgramPointTag Tag("NonLocalizedStringChecker",
    629                                     "UnlocalizedString");
    630   ErrNode = C.addTransition(C.getState(), C.getPredecessor(), &Tag);
    631 
    632   if (!ErrNode)
    633     return;
    634 
    635   // Generate the bug report.
    636   std::unique_ptr<BugReport> R(new BugReport(
    637       *BT, "User-facing text should use localized string macro", ErrNode));
    638   if (argumentNumber) {
    639     R->addRange(M.getArgExpr(argumentNumber - 1)->getSourceRange());
    640   } else {
    641     R->addRange(M.getSourceRange());
    642   }
    643   R->markInteresting(S);
    644   C.emitReport(std::move(R));
    645 }
    646 
    647 /// Returns the argument number requiring localized string if it exists
    648 /// otherwise, returns -1
    649 int NonLocalizedStringChecker::getLocalizedArgumentForSelector(
    650     const IdentifierInfo *Receiver, Selector S) const {
    651   auto method = UIMethods.find(Receiver);
    652 
    653   if (method == UIMethods.end())
    654     return -1;
    655 
    656   auto argumentIterator = method->getSecond().find(S);
    657 
    658   if (argumentIterator == method->getSecond().end())
    659     return -1;
    660 
    661   int argumentNumber = argumentIterator->getSecond();
    662   return argumentNumber;
    663 }
    664 
    665 /// Check if the string being passed in has NonLocalized state
    666 void NonLocalizedStringChecker::checkPreObjCMessage(const ObjCMethodCall &msg,
    667                                                     CheckerContext &C) const {
    668   initUIMethods(C.getASTContext());
    669 
    670   const ObjCInterfaceDecl *OD = msg.getReceiverInterface();
    671   if (!OD)
    672     return;
    673   const IdentifierInfo *odInfo = OD->getIdentifier();
    674 
    675   Selector S = msg.getSelector();
    676 
    677   std::string SelectorString = S.getAsString();
    678   StringRef SelectorName = SelectorString;
    679   assert(!SelectorName.empty());
    680 
    681   if (odInfo->isStr("NSString")) {
    682     // Handle the case where the receiver is an NSString
    683     // These special NSString methods draw to the screen
    684 
    685     if (!(SelectorName.startswith("drawAtPoint") ||
    686           SelectorName.startswith("drawInRect") ||
    687           SelectorName.startswith("drawWithRect")))
    688       return;
    689 
    690     SVal svTitle = msg.getReceiverSVal();
    691 
    692     bool isNonLocalized = hasNonLocalizedState(svTitle, C);
    693 
    694     if (isNonLocalized) {
    695       reportLocalizationError(svTitle, msg, C);
    696     }
    697   }
    698 
    699   int argumentNumber = getLocalizedArgumentForSelector(odInfo, S);
    700   // Go up each hierarchy of superclasses and their protocols
    701   while (argumentNumber < 0 && OD->getSuperClass() != nullptr) {
    702     for (const auto *P : OD->all_referenced_protocols()) {
    703       argumentNumber = getLocalizedArgumentForSelector(P->getIdentifier(), S);
    704       if (argumentNumber >= 0)
    705         break;
    706     }
    707     if (argumentNumber < 0) {
    708       OD = OD->getSuperClass();
    709       argumentNumber = getLocalizedArgumentForSelector(OD->getIdentifier(), S);
    710     }
    711   }
    712 
    713   if (argumentNumber < 0) // There was no match in UIMethods
    714     return;
    715 
    716   SVal svTitle = msg.getArgSVal(argumentNumber);
    717 
    718   if (const ObjCStringRegion *SR =
    719           dyn_cast_or_null<ObjCStringRegion>(svTitle.getAsRegion())) {
    720     StringRef stringValue =
    721         SR->getObjCStringLiteral()->getString()->getString();
    722     if ((stringValue.trim().size() == 0 && stringValue.size() > 0) ||
    723         stringValue.empty())
    724       return;
    725     if (!IsAggressive && llvm::sys::unicode::columnWidthUTF8(stringValue) < 2)
    726       return;
    727   }
    728 
    729   bool isNonLocalized = hasNonLocalizedState(svTitle, C);
    730 
    731   if (isNonLocalized) {
    732     reportLocalizationError(svTitle, msg, C, argumentNumber + 1);
    733   }
    734 }
    735 
    736 static inline bool isNSStringType(QualType T, ASTContext &Ctx) {
    737 
    738   const ObjCObjectPointerType *PT = T->getAs<ObjCObjectPointerType>();
    739   if (!PT)
    740     return false;
    741 
    742   ObjCInterfaceDecl *Cls = PT->getObjectType()->getInterface();
    743   if (!Cls)
    744     return false;
    745 
    746   IdentifierInfo *ClsName = Cls->getIdentifier();
    747 
    748   // FIXME: Should we walk the chain of classes?
    749   return ClsName == &Ctx.Idents.get("NSString") ||
    750          ClsName == &Ctx.Idents.get("NSMutableString");
    751 }
    752 
    753 /// Marks a string being returned by any call as localized
    754 /// if it is in LocStringFunctions (LSF) or the function is annotated.
    755 /// Otherwise, we mark it as NonLocalized (Aggressive) or
    756 /// NonLocalized only if it is not backed by a SymRegion (Non-Aggressive),
    757 /// basically leaving only string literals as NonLocalized.
    758 void NonLocalizedStringChecker::checkPostCall(const CallEvent &Call,
    759                                               CheckerContext &C) const {
    760   initLocStringsMethods(C.getASTContext());
    761 
    762   if (!Call.getOriginExpr())
    763     return;
    764 
    765   // Anything that takes in a localized NSString as an argument
    766   // and returns an NSString will be assumed to be returning a
    767   // localized NSString. (Counter: Incorrectly combining two LocalizedStrings)
    768   const QualType RT = Call.getResultType();
    769   if (isNSStringType(RT, C.getASTContext())) {
    770     for (unsigned i = 0; i < Call.getNumArgs(); ++i) {
    771       SVal argValue = Call.getArgSVal(i);
    772       if (hasLocalizedState(argValue, C)) {
    773         SVal sv = Call.getReturnValue();
    774         setLocalizedState(sv, C);
    775         return;
    776       }
    777     }
    778   }
    779 
    780   const Decl *D = Call.getDecl();
    781   if (!D)
    782     return;
    783 
    784   const IdentifierInfo *Identifier = Call.getCalleeIdentifier();
    785 
    786   SVal sv = Call.getReturnValue();
    787   if (isAnnotatedAsLocalized(D) || LSF.count(Identifier) != 0) {
    788     setLocalizedState(sv, C);
    789   } else if (isNSStringType(RT, C.getASTContext()) &&
    790              !hasLocalizedState(sv, C)) {
    791     if (IsAggressive) {
    792       setNonLocalizedState(sv, C);
    793     } else {
    794       const SymbolicRegion *SymReg =
    795           dyn_cast_or_null<SymbolicRegion>(sv.getAsRegion());
    796       if (!SymReg)
    797         setNonLocalizedState(sv, C);
    798     }
    799   }
    800 }
    801 
    802 /// Marks a string being returned by an ObjC method as localized
    803 /// if it is in LocStringMethods or the method is annotated
    804 void NonLocalizedStringChecker::checkPostObjCMessage(const ObjCMethodCall &msg,
    805                                                      CheckerContext &C) const {
    806   initLocStringsMethods(C.getASTContext());
    807 
    808   if (!msg.isInstanceMessage())
    809     return;
    810 
    811   const ObjCInterfaceDecl *OD = msg.getReceiverInterface();
    812   if (!OD)
    813     return;
    814   const IdentifierInfo *odInfo = OD->getIdentifier();
    815 
    816   Selector S = msg.getSelector();
    817   std::string SelectorName = S.getAsString();
    818 
    819   std::pair<const IdentifierInfo *, Selector> MethodDescription = {odInfo, S};
    820 
    821   if (LSM.count(MethodDescription) || isAnnotatedAsLocalized(msg.getDecl())) {
    822     SVal sv = msg.getReturnValue();
    823     setLocalizedState(sv, C);
    824   }
    825 }
    826 
    827 /// Marks all empty string literals as localized
    828 void NonLocalizedStringChecker::checkPostStmt(const ObjCStringLiteral *SL,
    829                                               CheckerContext &C) const {
    830   SVal sv = C.getSVal(SL);
    831   setNonLocalizedState(sv, C);
    832 }
    833 
    834 namespace {
    835 class EmptyLocalizationContextChecker
    836     : public Checker<check::ASTDecl<ObjCImplementationDecl>> {
    837 
    838   // A helper class, which walks the AST
    839   class MethodCrawler : public ConstStmtVisitor<MethodCrawler> {
    840     const ObjCMethodDecl *MD;
    841     BugReporter &BR;
    842     AnalysisManager &Mgr;
    843     const CheckerBase *Checker;
    844     LocationOrAnalysisDeclContext DCtx;
    845 
    846   public:
    847     MethodCrawler(const ObjCMethodDecl *InMD, BugReporter &InBR,
    848                   const CheckerBase *Checker, AnalysisManager &InMgr,
    849                   AnalysisDeclContext *InDCtx)
    850         : MD(InMD), BR(InBR), Mgr(InMgr), Checker(Checker), DCtx(InDCtx) {}
    851 
    852     void VisitStmt(const Stmt *S) { VisitChildren(S); }
    853 
    854     void VisitObjCMessageExpr(const ObjCMessageExpr *ME);
    855 
    856     void reportEmptyContextError(const ObjCMessageExpr *M) const;
    857 
    858     void VisitChildren(const Stmt *S) {
    859       for (const Stmt *Child : S->children()) {
    860         if (Child)
    861           this->Visit(Child);
    862       }
    863     }
    864   };
    865 
    866 public:
    867   void checkASTDecl(const ObjCImplementationDecl *D, AnalysisManager &Mgr,
    868                     BugReporter &BR) const;
    869 };
    870 } // end anonymous namespace
    871 
    872 void EmptyLocalizationContextChecker::checkASTDecl(
    873     const ObjCImplementationDecl *D, AnalysisManager &Mgr,
    874     BugReporter &BR) const {
    875 
    876   for (const ObjCMethodDecl *M : D->methods()) {
    877     AnalysisDeclContext *DCtx = Mgr.getAnalysisDeclContext(M);
    878 
    879     const Stmt *Body = M->getBody();
    880     assert(Body);
    881 
    882     MethodCrawler MC(M->getCanonicalDecl(), BR, this, Mgr, DCtx);
    883     MC.VisitStmt(Body);
    884   }
    885 }
    886 
    887 /// This check attempts to match these macros, assuming they are defined as
    888 /// follows:
    889 ///
    890 /// #define NSLocalizedString(key, comment) \
    891 /// [[NSBundle mainBundle] localizedStringForKey:(key) value:@"" table:nil]
    892 /// #define NSLocalizedStringFromTable(key, tbl, comment) \
    893 /// [[NSBundle mainBundle] localizedStringForKey:(key) value:@"" table:(tbl)]
    894 /// #define NSLocalizedStringFromTableInBundle(key, tbl, bundle, comment) \
    895 /// [bundle localizedStringForKey:(key) value:@"" table:(tbl)]
    896 /// #define NSLocalizedStringWithDefaultValue(key, tbl, bundle, val, comment)
    897 ///
    898 /// We cannot use the path sensitive check because the macro argument we are
    899 /// checking for (comment) is not used and thus not present in the AST,
    900 /// so we use Lexer on the original macro call and retrieve the value of
    901 /// the comment. If it's empty or nil, we raise a warning.
    902 void EmptyLocalizationContextChecker::MethodCrawler::VisitObjCMessageExpr(
    903     const ObjCMessageExpr *ME) {
    904 
    905   const ObjCInterfaceDecl *OD = ME->getReceiverInterface();
    906   if (!OD)
    907     return;
    908 
    909   const IdentifierInfo *odInfo = OD->getIdentifier();
    910 
    911   if (!(odInfo->isStr("NSBundle") &&
    912         ME->getSelector().getAsString() ==
    913             "localizedStringForKey:value:table:")) {
    914     return;
    915   }
    916 
    917   SourceRange R = ME->getSourceRange();
    918   if (!R.getBegin().isMacroID())
    919     return;
    920 
    921   // getImmediateMacroCallerLoc gets the location of the immediate macro
    922   // caller, one level up the stack toward the initial macro typed into the
    923   // source, so SL should point to the NSLocalizedString macro.
    924   SourceLocation SL =
    925       Mgr.getSourceManager().getImmediateMacroCallerLoc(R.getBegin());
    926   std::pair<FileID, unsigned> SLInfo =
    927       Mgr.getSourceManager().getDecomposedLoc(SL);
    928 
    929   SrcMgr::SLocEntry SE = Mgr.getSourceManager().getSLocEntry(SLInfo.first);
    930 
    931   // If NSLocalizedString macro is wrapped in another macro, we need to
    932   // unwrap the expansion until we get to the NSLocalizedStringMacro.
    933   while (SE.isExpansion()) {
    934     SL = SE.getExpansion().getSpellingLoc();
    935     SLInfo = Mgr.getSourceManager().getDecomposedLoc(SL);
    936     SE = Mgr.getSourceManager().getSLocEntry(SLInfo.first);
    937   }
    938 
    939   llvm::MemoryBuffer *BF = SE.getFile().getContentCache()->getRawBuffer();
    940   Lexer TheLexer(SL, LangOptions(), BF->getBufferStart(),
    941                  BF->getBufferStart() + SLInfo.second, BF->getBufferEnd());
    942 
    943   Token I;
    944   Token Result;    // This will hold the token just before the last ')'
    945   int p_count = 0; // This is for parenthesis matching
    946   while (!TheLexer.LexFromRawLexer(I)) {
    947     if (I.getKind() == tok::l_paren)
    948       ++p_count;
    949     if (I.getKind() == tok::r_paren) {
    950       if (p_count == 1)
    951         break;
    952       --p_count;
    953     }
    954     Result = I;
    955   }
    956 
    957   if (isAnyIdentifier(Result.getKind())) {
    958     if (Result.getRawIdentifier().equals("nil")) {
    959       reportEmptyContextError(ME);
    960       return;
    961     }
    962   }
    963 
    964   if (!isStringLiteral(Result.getKind()))
    965     return;
    966 
    967   StringRef Comment =
    968       StringRef(Result.getLiteralData(), Result.getLength()).trim("\"");
    969 
    970   if ((Comment.trim().size() == 0 && Comment.size() > 0) || // Is Whitespace
    971       Comment.empty()) {
    972     reportEmptyContextError(ME);
    973   }
    974 }
    975 
    976 void EmptyLocalizationContextChecker::MethodCrawler::reportEmptyContextError(
    977     const ObjCMessageExpr *ME) const {
    978   // Generate the bug report.
    979   BR.EmitBasicReport(MD, Checker, "Context Missing",
    980                      "Localizability Issue (Apple)",
    981                      "Localized string macro should include a non-empty "
    982                      "comment for translators",
    983                      PathDiagnosticLocation(ME, BR.getSourceManager(), DCtx));
    984 }
    985 
    986 namespace {
    987 class PluralMisuseChecker : public Checker<check::ASTCodeBody> {
    988 
    989   // A helper class, which walks the AST
    990   class MethodCrawler : public RecursiveASTVisitor<MethodCrawler> {
    991     BugReporter &BR;
    992     const CheckerBase *Checker;
    993     AnalysisDeclContext *AC;
    994 
    995     // This functions like a stack. We push on any IfStmt or
    996     // ConditionalOperator that matches the condition
    997     // and pop it off when we leave that statement
    998     llvm::SmallVector<const clang::Stmt *, 8> MatchingStatements;
    999     // This is true when we are the direct-child of a
   1000     // matching statement
   1001     bool InMatchingStatement = false;
   1002 
   1003   public:
   1004     explicit MethodCrawler(BugReporter &InBR, const CheckerBase *Checker,
   1005                            AnalysisDeclContext *InAC)
   1006         : BR(InBR), Checker(Checker), AC(InAC) {}
   1007 
   1008     bool VisitIfStmt(const IfStmt *I);
   1009     bool EndVisitIfStmt(IfStmt *I);
   1010     bool TraverseIfStmt(IfStmt *x);
   1011     bool VisitConditionalOperator(const ConditionalOperator *C);
   1012     bool TraverseConditionalOperator(ConditionalOperator *C);
   1013     bool VisitCallExpr(const CallExpr *CE);
   1014     bool VisitObjCMessageExpr(const ObjCMessageExpr *ME);
   1015 
   1016   private:
   1017     void reportPluralMisuseError(const Stmt *S) const;
   1018     bool isCheckingPlurality(const Expr *E) const;
   1019   };
   1020 
   1021 public:
   1022   void checkASTCodeBody(const Decl *D, AnalysisManager &Mgr,
   1023                         BugReporter &BR) const {
   1024     MethodCrawler Visitor(BR, this, Mgr.getAnalysisDeclContext(D));
   1025     Visitor.TraverseDecl(const_cast<Decl *>(D));
   1026   }
   1027 };
   1028 } // end anonymous namespace
   1029 
   1030 // Checks the condition of the IfStmt and returns true if one
   1031 // of the following heuristics are met:
   1032 // 1) The conidtion is a variable with "singular" or "plural" in the name
   1033 // 2) The condition is a binary operator with 1 or 2 on the right-hand side
   1034 bool PluralMisuseChecker::MethodCrawler::isCheckingPlurality(
   1035     const Expr *Condition) const {
   1036   const BinaryOperator *BO = nullptr;
   1037   // Accounts for when a VarDecl represents a BinaryOperator
   1038   if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Condition)) {
   1039     if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
   1040       const Expr *InitExpr = VD->getInit();
   1041       if (InitExpr) {
   1042         if (const BinaryOperator *B =
   1043                 dyn_cast<BinaryOperator>(InitExpr->IgnoreParenImpCasts())) {
   1044           BO = B;
   1045         }
   1046       }
   1047       if (VD->getName().lower().find("plural") != StringRef::npos ||
   1048           VD->getName().lower().find("singular") != StringRef::npos) {
   1049         return true;
   1050       }
   1051     }
   1052   } else if (const BinaryOperator *B = dyn_cast<BinaryOperator>(Condition)) {
   1053     BO = B;
   1054   }
   1055 
   1056   if (BO == nullptr)
   1057     return false;
   1058 
   1059   if (IntegerLiteral *IL = dyn_cast_or_null<IntegerLiteral>(
   1060           BO->getRHS()->IgnoreParenImpCasts())) {
   1061     llvm::APInt Value = IL->getValue();
   1062     if (Value == 1 || Value == 2) {
   1063       return true;
   1064     }
   1065   }
   1066   return false;
   1067 }
   1068 
   1069 // A CallExpr with "LOC" in its identifier that takes in a string literal
   1070 // has been shown to almost always be a function that returns a localized
   1071 // string. Raise a diagnostic when this is in a statement that matches
   1072 // the condition.
   1073 bool PluralMisuseChecker::MethodCrawler::VisitCallExpr(const CallExpr *CE) {
   1074   if (InMatchingStatement) {
   1075     if (const FunctionDecl *FD = CE->getDirectCallee()) {
   1076       std::string NormalizedName =
   1077           StringRef(FD->getNameInfo().getAsString()).lower();
   1078       if (NormalizedName.find("loc") != std::string::npos) {
   1079         for (const Expr *Arg : CE->arguments()) {
   1080           if (isa<ObjCStringLiteral>(Arg))
   1081             reportPluralMisuseError(CE);
   1082         }
   1083       }
   1084     }
   1085   }
   1086   return true;
   1087 }
   1088 
   1089 // The other case is for NSLocalizedString which also returns
   1090 // a localized string. It's a macro for the ObjCMessageExpr
   1091 // [NSBundle localizedStringForKey:value:table:] Raise a
   1092 // diagnostic when this is in a statement that matches
   1093 // the condition.
   1094 bool PluralMisuseChecker::MethodCrawler::VisitObjCMessageExpr(
   1095     const ObjCMessageExpr *ME) {
   1096   const ObjCInterfaceDecl *OD = ME->getReceiverInterface();
   1097   if (!OD)
   1098     return true;
   1099 
   1100   const IdentifierInfo *odInfo = OD->getIdentifier();
   1101 
   1102   if (odInfo->isStr("NSBundle") &&
   1103       ME->getSelector().getAsString() == "localizedStringForKey:value:table:") {
   1104     if (InMatchingStatement) {
   1105       reportPluralMisuseError(ME);
   1106     }
   1107   }
   1108   return true;
   1109 }
   1110 
   1111 /// Override TraverseIfStmt so we know when we are done traversing an IfStmt
   1112 bool PluralMisuseChecker::MethodCrawler::TraverseIfStmt(IfStmt *I) {
   1113   RecursiveASTVisitor<MethodCrawler>::TraverseIfStmt(I);
   1114   return EndVisitIfStmt(I);
   1115 }
   1116 
   1117 // EndVisit callbacks are not provided by the RecursiveASTVisitor
   1118 // so we override TraverseIfStmt and make a call to EndVisitIfStmt
   1119 // after traversing the IfStmt
   1120 bool PluralMisuseChecker::MethodCrawler::EndVisitIfStmt(IfStmt *I) {
   1121   MatchingStatements.pop_back();
   1122   if (!MatchingStatements.empty()) {
   1123     if (MatchingStatements.back() != nullptr) {
   1124       InMatchingStatement = true;
   1125       return true;
   1126     }
   1127   }
   1128   InMatchingStatement = false;
   1129   return true;
   1130 }
   1131 
   1132 bool PluralMisuseChecker::MethodCrawler::VisitIfStmt(const IfStmt *I) {
   1133   const Expr *Condition = I->getCond()->IgnoreParenImpCasts();
   1134   if (isCheckingPlurality(Condition)) {
   1135     MatchingStatements.push_back(I);
   1136     InMatchingStatement = true;
   1137   } else {
   1138     MatchingStatements.push_back(nullptr);
   1139     InMatchingStatement = false;
   1140   }
   1141 
   1142   return true;
   1143 }
   1144 
   1145 // Preliminary support for conditional operators.
   1146 bool PluralMisuseChecker::MethodCrawler::TraverseConditionalOperator(
   1147     ConditionalOperator *C) {
   1148   RecursiveASTVisitor<MethodCrawler>::TraverseConditionalOperator(C);
   1149   MatchingStatements.pop_back();
   1150   if (!MatchingStatements.empty()) {
   1151     if (MatchingStatements.back() != nullptr)
   1152       InMatchingStatement = true;
   1153     else
   1154       InMatchingStatement = false;
   1155   } else {
   1156     InMatchingStatement = false;
   1157   }
   1158   return true;
   1159 }
   1160 
   1161 bool PluralMisuseChecker::MethodCrawler::VisitConditionalOperator(
   1162     const ConditionalOperator *C) {
   1163   const Expr *Condition = C->getCond()->IgnoreParenImpCasts();
   1164   if (isCheckingPlurality(Condition)) {
   1165     MatchingStatements.push_back(C);
   1166     InMatchingStatement = true;
   1167   } else {
   1168     MatchingStatements.push_back(nullptr);
   1169     InMatchingStatement = false;
   1170   }
   1171   return true;
   1172 }
   1173 
   1174 void PluralMisuseChecker::MethodCrawler::reportPluralMisuseError(
   1175     const Stmt *S) const {
   1176   // Generate the bug report.
   1177   BR.EmitBasicReport(AC->getDecl(), Checker, "Plural Misuse",
   1178                      "Localizability Issue (Apple)",
   1179                      "Plural cases are not supported accross all languages. "
   1180                      "Use a .stringsdict file instead",
   1181                      PathDiagnosticLocation(S, BR.getSourceManager(), AC));
   1182 }
   1183 
   1184 //===----------------------------------------------------------------------===//
   1185 // Checker registration.
   1186 //===----------------------------------------------------------------------===//
   1187 
   1188 void ento::registerNonLocalizedStringChecker(CheckerManager &mgr) {
   1189   NonLocalizedStringChecker *checker =
   1190       mgr.registerChecker<NonLocalizedStringChecker>();
   1191   checker->IsAggressive =
   1192       mgr.getAnalyzerOptions().getBooleanOption("AggressiveReport", false);
   1193 }
   1194 
   1195 void ento::registerEmptyLocalizationContextChecker(CheckerManager &mgr) {
   1196   mgr.registerChecker<EmptyLocalizationContextChecker>();
   1197 }
   1198 
   1199 void ento::registerPluralMisuseChecker(CheckerManager &mgr) {
   1200   mgr.registerChecker<PluralMisuseChecker>();
   1201 }
   1202