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 
623 static bool isDebuggingName(std::string name) {
624   return StringRef(name).lower().find("debug") != StringRef::npos;
625 }
626 
627 /// Returns true when, heuristically, the analyzer may be analyzing debugging
628 /// code. We use this to suppress localization diagnostics in un-localized user
629 /// interfaces that are only used for debugging and are therefore not user
630 /// facing.
631 static bool isDebuggingContext(CheckerContext &C) {
632   const Decl *D = C.getCurrentAnalysisDeclContext()->getDecl();
633   if (!D)
634     return false;
635 
636   if (auto *ND = dyn_cast<NamedDecl>(D)) {
637     if (isDebuggingName(ND->getNameAsString()))
638       return true;
639   }
640 
641   const DeclContext *DC = D->getDeclContext();
642 
643   if (auto *CD = dyn_cast<ObjCContainerDecl>(DC)) {
644     if (isDebuggingName(CD->getNameAsString()))
645       return true;
646   }
647 
648   return false;
649 }
650 
651 
652 /// Reports a localization error for the passed in method call and SVal
653 void NonLocalizedStringChecker::reportLocalizationError(
654     SVal S, const ObjCMethodCall &M, CheckerContext &C,
655     int argumentNumber) const {
656 
657   // Don't warn about localization errors in classes and methods that
658   // may be debug code.
659   if (isDebuggingContext(C))
660     return;
661 
662   ExplodedNode *ErrNode = C.getPredecessor();
663   static CheckerProgramPointTag Tag("NonLocalizedStringChecker",
664                                     "UnlocalizedString");
665   ErrNode = C.addTransition(C.getState(), C.getPredecessor(), &Tag);
666 
667   if (!ErrNode)
668     return;
669 
670   // Generate the bug report.
671   std::unique_ptr<BugReport> R(new BugReport(
672       *BT, "User-facing text should use localized string macro", ErrNode));
673   if (argumentNumber) {
674     R->addRange(M.getArgExpr(argumentNumber - 1)->getSourceRange());
675   } else {
676     R->addRange(M.getSourceRange());
677   }
678   R->markInteresting(S);
679   C.emitReport(std::move(R));
680 }
681 
682 /// Returns the argument number requiring localized string if it exists
683 /// otherwise, returns -1
684 int NonLocalizedStringChecker::getLocalizedArgumentForSelector(
685     const IdentifierInfo *Receiver, Selector S) const {
686   auto method = UIMethods.find(Receiver);
687 
688   if (method == UIMethods.end())
689     return -1;
690 
691   auto argumentIterator = method->getSecond().find(S);
692 
693   if (argumentIterator == method->getSecond().end())
694     return -1;
695 
696   int argumentNumber = argumentIterator->getSecond();
697   return argumentNumber;
698 }
699 
700 /// Check if the string being passed in has NonLocalized state
701 void NonLocalizedStringChecker::checkPreObjCMessage(const ObjCMethodCall &msg,
702                                                     CheckerContext &C) const {
703   initUIMethods(C.getASTContext());
704 
705   const ObjCInterfaceDecl *OD = msg.getReceiverInterface();
706   if (!OD)
707     return;
708   const IdentifierInfo *odInfo = OD->getIdentifier();
709 
710   Selector S = msg.getSelector();
711 
712   std::string SelectorString = S.getAsString();
713   StringRef SelectorName = SelectorString;
714   assert(!SelectorName.empty());
715 
716   if (odInfo->isStr("NSString")) {
717     // Handle the case where the receiver is an NSString
718     // These special NSString methods draw to the screen
719 
720     if (!(SelectorName.startswith("drawAtPoint") ||
721           SelectorName.startswith("drawInRect") ||
722           SelectorName.startswith("drawWithRect")))
723       return;
724 
725     SVal svTitle = msg.getReceiverSVal();
726 
727     bool isNonLocalized = hasNonLocalizedState(svTitle, C);
728 
729     if (isNonLocalized) {
730       reportLocalizationError(svTitle, msg, C);
731     }
732   }
733 
734   int argumentNumber = getLocalizedArgumentForSelector(odInfo, S);
735   // Go up each hierarchy of superclasses and their protocols
736   while (argumentNumber < 0 && OD->getSuperClass() != nullptr) {
737     for (const auto *P : OD->all_referenced_protocols()) {
738       argumentNumber = getLocalizedArgumentForSelector(P->getIdentifier(), S);
739       if (argumentNumber >= 0)
740         break;
741     }
742     if (argumentNumber < 0) {
743       OD = OD->getSuperClass();
744       argumentNumber = getLocalizedArgumentForSelector(OD->getIdentifier(), S);
745     }
746   }
747 
748   if (argumentNumber < 0) // There was no match in UIMethods
749     return;
750 
751   SVal svTitle = msg.getArgSVal(argumentNumber);
752 
753   if (const ObjCStringRegion *SR =
754           dyn_cast_or_null<ObjCStringRegion>(svTitle.getAsRegion())) {
755     StringRef stringValue =
756         SR->getObjCStringLiteral()->getString()->getString();
757     if ((stringValue.trim().size() == 0 && stringValue.size() > 0) ||
758         stringValue.empty())
759       return;
760     if (!IsAggressive && llvm::sys::unicode::columnWidthUTF8(stringValue) < 2)
761       return;
762   }
763 
764   bool isNonLocalized = hasNonLocalizedState(svTitle, C);
765 
766   if (isNonLocalized) {
767     reportLocalizationError(svTitle, msg, C, argumentNumber + 1);
768   }
769 }
770 
771 static inline bool isNSStringType(QualType T, ASTContext &Ctx) {
772 
773   const ObjCObjectPointerType *PT = T->getAs<ObjCObjectPointerType>();
774   if (!PT)
775     return false;
776 
777   ObjCInterfaceDecl *Cls = PT->getObjectType()->getInterface();
778   if (!Cls)
779     return false;
780 
781   IdentifierInfo *ClsName = Cls->getIdentifier();
782 
783   // FIXME: Should we walk the chain of classes?
784   return ClsName == &Ctx.Idents.get("NSString") ||
785          ClsName == &Ctx.Idents.get("NSMutableString");
786 }
787 
788 /// Marks a string being returned by any call as localized
789 /// if it is in LocStringFunctions (LSF) or the function is annotated.
790 /// Otherwise, we mark it as NonLocalized (Aggressive) or
791 /// NonLocalized only if it is not backed by a SymRegion (Non-Aggressive),
792 /// basically leaving only string literals as NonLocalized.
793 void NonLocalizedStringChecker::checkPostCall(const CallEvent &Call,
794                                               CheckerContext &C) const {
795   initLocStringsMethods(C.getASTContext());
796 
797   if (!Call.getOriginExpr())
798     return;
799 
800   // Anything that takes in a localized NSString as an argument
801   // and returns an NSString will be assumed to be returning a
802   // localized NSString. (Counter: Incorrectly combining two LocalizedStrings)
803   const QualType RT = Call.getResultType();
804   if (isNSStringType(RT, C.getASTContext())) {
805     for (unsigned i = 0; i < Call.getNumArgs(); ++i) {
806       SVal argValue = Call.getArgSVal(i);
807       if (hasLocalizedState(argValue, C)) {
808         SVal sv = Call.getReturnValue();
809         setLocalizedState(sv, C);
810         return;
811       }
812     }
813   }
814 
815   const Decl *D = Call.getDecl();
816   if (!D)
817     return;
818 
819   const IdentifierInfo *Identifier = Call.getCalleeIdentifier();
820 
821   SVal sv = Call.getReturnValue();
822   if (isAnnotatedAsLocalized(D) || LSF.count(Identifier) != 0) {
823     setLocalizedState(sv, C);
824   } else if (isNSStringType(RT, C.getASTContext()) &&
825              !hasLocalizedState(sv, C)) {
826     if (IsAggressive) {
827       setNonLocalizedState(sv, C);
828     } else {
829       const SymbolicRegion *SymReg =
830           dyn_cast_or_null<SymbolicRegion>(sv.getAsRegion());
831       if (!SymReg)
832         setNonLocalizedState(sv, C);
833     }
834   }
835 }
836 
837 /// Marks a string being returned by an ObjC method as localized
838 /// if it is in LocStringMethods or the method is annotated
839 void NonLocalizedStringChecker::checkPostObjCMessage(const ObjCMethodCall &msg,
840                                                      CheckerContext &C) const {
841   initLocStringsMethods(C.getASTContext());
842 
843   if (!msg.isInstanceMessage())
844     return;
845 
846   const ObjCInterfaceDecl *OD = msg.getReceiverInterface();
847   if (!OD)
848     return;
849   const IdentifierInfo *odInfo = OD->getIdentifier();
850 
851   Selector S = msg.getSelector();
852   std::string SelectorName = S.getAsString();
853 
854   std::pair<const IdentifierInfo *, Selector> MethodDescription = {odInfo, S};
855 
856   if (LSM.count(MethodDescription) || isAnnotatedAsLocalized(msg.getDecl())) {
857     SVal sv = msg.getReturnValue();
858     setLocalizedState(sv, C);
859   }
860 }
861 
862 /// Marks all empty string literals as localized
863 void NonLocalizedStringChecker::checkPostStmt(const ObjCStringLiteral *SL,
864                                               CheckerContext &C) const {
865   SVal sv = C.getSVal(SL);
866   setNonLocalizedState(sv, C);
867 }
868 
869 namespace {
870 class EmptyLocalizationContextChecker
871     : public Checker<check::ASTDecl<ObjCImplementationDecl>> {
872 
873   // A helper class, which walks the AST
874   class MethodCrawler : public ConstStmtVisitor<MethodCrawler> {
875     const ObjCMethodDecl *MD;
876     BugReporter &BR;
877     AnalysisManager &Mgr;
878     const CheckerBase *Checker;
879     LocationOrAnalysisDeclContext DCtx;
880 
881   public:
882     MethodCrawler(const ObjCMethodDecl *InMD, BugReporter &InBR,
883                   const CheckerBase *Checker, AnalysisManager &InMgr,
884                   AnalysisDeclContext *InDCtx)
885         : MD(InMD), BR(InBR), Mgr(InMgr), Checker(Checker), DCtx(InDCtx) {}
886 
887     void VisitStmt(const Stmt *S) { VisitChildren(S); }
888 
889     void VisitObjCMessageExpr(const ObjCMessageExpr *ME);
890 
891     void reportEmptyContextError(const ObjCMessageExpr *M) const;
892 
893     void VisitChildren(const Stmt *S) {
894       for (const Stmt *Child : S->children()) {
895         if (Child)
896           this->Visit(Child);
897       }
898     }
899   };
900 
901 public:
902   void checkASTDecl(const ObjCImplementationDecl *D, AnalysisManager &Mgr,
903                     BugReporter &BR) const;
904 };
905 } // end anonymous namespace
906 
907 void EmptyLocalizationContextChecker::checkASTDecl(
908     const ObjCImplementationDecl *D, AnalysisManager &Mgr,
909     BugReporter &BR) const {
910 
911   for (const ObjCMethodDecl *M : D->methods()) {
912     AnalysisDeclContext *DCtx = Mgr.getAnalysisDeclContext(M);
913 
914     const Stmt *Body = M->getBody();
915     assert(Body);
916 
917     MethodCrawler MC(M->getCanonicalDecl(), BR, this, Mgr, DCtx);
918     MC.VisitStmt(Body);
919   }
920 }
921 
922 /// This check attempts to match these macros, assuming they are defined as
923 /// follows:
924 ///
925 /// #define NSLocalizedString(key, comment) \
926 /// [[NSBundle mainBundle] localizedStringForKey:(key) value:@"" table:nil]
927 /// #define NSLocalizedStringFromTable(key, tbl, comment) \
928 /// [[NSBundle mainBundle] localizedStringForKey:(key) value:@"" table:(tbl)]
929 /// #define NSLocalizedStringFromTableInBundle(key, tbl, bundle, comment) \
930 /// [bundle localizedStringForKey:(key) value:@"" table:(tbl)]
931 /// #define NSLocalizedStringWithDefaultValue(key, tbl, bundle, val, comment)
932 ///
933 /// We cannot use the path sensitive check because the macro argument we are
934 /// checking for (comment) is not used and thus not present in the AST,
935 /// so we use Lexer on the original macro call and retrieve the value of
936 /// the comment. If it's empty or nil, we raise a warning.
937 void EmptyLocalizationContextChecker::MethodCrawler::VisitObjCMessageExpr(
938     const ObjCMessageExpr *ME) {
939 
940   const ObjCInterfaceDecl *OD = ME->getReceiverInterface();
941   if (!OD)
942     return;
943 
944   const IdentifierInfo *odInfo = OD->getIdentifier();
945 
946   if (!(odInfo->isStr("NSBundle") &&
947         ME->getSelector().getAsString() ==
948             "localizedStringForKey:value:table:")) {
949     return;
950   }
951 
952   SourceRange R = ME->getSourceRange();
953   if (!R.getBegin().isMacroID())
954     return;
955 
956   // getImmediateMacroCallerLoc gets the location of the immediate macro
957   // caller, one level up the stack toward the initial macro typed into the
958   // source, so SL should point to the NSLocalizedString macro.
959   SourceLocation SL =
960       Mgr.getSourceManager().getImmediateMacroCallerLoc(R.getBegin());
961   std::pair<FileID, unsigned> SLInfo =
962       Mgr.getSourceManager().getDecomposedLoc(SL);
963 
964   SrcMgr::SLocEntry SE = Mgr.getSourceManager().getSLocEntry(SLInfo.first);
965 
966   // If NSLocalizedString macro is wrapped in another macro, we need to
967   // unwrap the expansion until we get to the NSLocalizedStringMacro.
968   while (SE.isExpansion()) {
969     SL = SE.getExpansion().getSpellingLoc();
970     SLInfo = Mgr.getSourceManager().getDecomposedLoc(SL);
971     SE = Mgr.getSourceManager().getSLocEntry(SLInfo.first);
972   }
973 
974   llvm::MemoryBuffer *BF = SE.getFile().getContentCache()->getRawBuffer();
975   Lexer TheLexer(SL, LangOptions(), BF->getBufferStart(),
976                  BF->getBufferStart() + SLInfo.second, BF->getBufferEnd());
977 
978   Token I;
979   Token Result;    // This will hold the token just before the last ')'
980   int p_count = 0; // This is for parenthesis matching
981   while (!TheLexer.LexFromRawLexer(I)) {
982     if (I.getKind() == tok::l_paren)
983       ++p_count;
984     if (I.getKind() == tok::r_paren) {
985       if (p_count == 1)
986         break;
987       --p_count;
988     }
989     Result = I;
990   }
991 
992   if (isAnyIdentifier(Result.getKind())) {
993     if (Result.getRawIdentifier().equals("nil")) {
994       reportEmptyContextError(ME);
995       return;
996     }
997   }
998 
999   if (!isStringLiteral(Result.getKind()))
1000     return;
1001 
1002   StringRef Comment =
1003       StringRef(Result.getLiteralData(), Result.getLength()).trim('"');
1004 
1005   if ((Comment.trim().size() == 0 && Comment.size() > 0) || // Is Whitespace
1006       Comment.empty()) {
1007     reportEmptyContextError(ME);
1008   }
1009 }
1010 
1011 void EmptyLocalizationContextChecker::MethodCrawler::reportEmptyContextError(
1012     const ObjCMessageExpr *ME) const {
1013   // Generate the bug report.
1014   BR.EmitBasicReport(MD, Checker, "Context Missing",
1015                      "Localizability Issue (Apple)",
1016                      "Localized string macro should include a non-empty "
1017                      "comment for translators",
1018                      PathDiagnosticLocation(ME, BR.getSourceManager(), DCtx));
1019 }
1020 
1021 namespace {
1022 class PluralMisuseChecker : public Checker<check::ASTCodeBody> {
1023 
1024   // A helper class, which walks the AST
1025   class MethodCrawler : public RecursiveASTVisitor<MethodCrawler> {
1026     BugReporter &BR;
1027     const CheckerBase *Checker;
1028     AnalysisDeclContext *AC;
1029 
1030     // This functions like a stack. We push on any IfStmt or
1031     // ConditionalOperator that matches the condition
1032     // and pop it off when we leave that statement
1033     llvm::SmallVector<const clang::Stmt *, 8> MatchingStatements;
1034     // This is true when we are the direct-child of a
1035     // matching statement
1036     bool InMatchingStatement = false;
1037 
1038   public:
1039     explicit MethodCrawler(BugReporter &InBR, const CheckerBase *Checker,
1040                            AnalysisDeclContext *InAC)
1041         : BR(InBR), Checker(Checker), AC(InAC) {}
1042 
1043     bool VisitIfStmt(const IfStmt *I);
1044     bool EndVisitIfStmt(IfStmt *I);
1045     bool TraverseIfStmt(IfStmt *x);
1046     bool VisitConditionalOperator(const ConditionalOperator *C);
1047     bool TraverseConditionalOperator(ConditionalOperator *C);
1048     bool VisitCallExpr(const CallExpr *CE);
1049     bool VisitObjCMessageExpr(const ObjCMessageExpr *ME);
1050 
1051   private:
1052     void reportPluralMisuseError(const Stmt *S) const;
1053     bool isCheckingPlurality(const Expr *E) const;
1054   };
1055 
1056 public:
1057   void checkASTCodeBody(const Decl *D, AnalysisManager &Mgr,
1058                         BugReporter &BR) const {
1059     MethodCrawler Visitor(BR, this, Mgr.getAnalysisDeclContext(D));
1060     Visitor.TraverseDecl(const_cast<Decl *>(D));
1061   }
1062 };
1063 } // end anonymous namespace
1064 
1065 // Checks the condition of the IfStmt and returns true if one
1066 // of the following heuristics are met:
1067 // 1) The conidtion is a variable with "singular" or "plural" in the name
1068 // 2) The condition is a binary operator with 1 or 2 on the right-hand side
1069 bool PluralMisuseChecker::MethodCrawler::isCheckingPlurality(
1070     const Expr *Condition) const {
1071   const BinaryOperator *BO = nullptr;
1072   // Accounts for when a VarDecl represents a BinaryOperator
1073   if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Condition)) {
1074     if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
1075       const Expr *InitExpr = VD->getInit();
1076       if (InitExpr) {
1077         if (const BinaryOperator *B =
1078                 dyn_cast<BinaryOperator>(InitExpr->IgnoreParenImpCasts())) {
1079           BO = B;
1080         }
1081       }
1082       if (VD->getName().lower().find("plural") != StringRef::npos ||
1083           VD->getName().lower().find("singular") != StringRef::npos) {
1084         return true;
1085       }
1086     }
1087   } else if (const BinaryOperator *B = dyn_cast<BinaryOperator>(Condition)) {
1088     BO = B;
1089   }
1090 
1091   if (BO == nullptr)
1092     return false;
1093 
1094   if (IntegerLiteral *IL = dyn_cast_or_null<IntegerLiteral>(
1095           BO->getRHS()->IgnoreParenImpCasts())) {
1096     llvm::APInt Value = IL->getValue();
1097     if (Value == 1 || Value == 2) {
1098       return true;
1099     }
1100   }
1101   return false;
1102 }
1103 
1104 // A CallExpr with "LOC" in its identifier that takes in a string literal
1105 // has been shown to almost always be a function that returns a localized
1106 // string. Raise a diagnostic when this is in a statement that matches
1107 // the condition.
1108 bool PluralMisuseChecker::MethodCrawler::VisitCallExpr(const CallExpr *CE) {
1109   if (InMatchingStatement) {
1110     if (const FunctionDecl *FD = CE->getDirectCallee()) {
1111       std::string NormalizedName =
1112           StringRef(FD->getNameInfo().getAsString()).lower();
1113       if (NormalizedName.find("loc") != std::string::npos) {
1114         for (const Expr *Arg : CE->arguments()) {
1115           if (isa<ObjCStringLiteral>(Arg))
1116             reportPluralMisuseError(CE);
1117         }
1118       }
1119     }
1120   }
1121   return true;
1122 }
1123 
1124 // The other case is for NSLocalizedString which also returns
1125 // a localized string. It's a macro for the ObjCMessageExpr
1126 // [NSBundle localizedStringForKey:value:table:] Raise a
1127 // diagnostic when this is in a statement that matches
1128 // the condition.
1129 bool PluralMisuseChecker::MethodCrawler::VisitObjCMessageExpr(
1130     const ObjCMessageExpr *ME) {
1131   const ObjCInterfaceDecl *OD = ME->getReceiverInterface();
1132   if (!OD)
1133     return true;
1134 
1135   const IdentifierInfo *odInfo = OD->getIdentifier();
1136 
1137   if (odInfo->isStr("NSBundle") &&
1138       ME->getSelector().getAsString() == "localizedStringForKey:value:table:") {
1139     if (InMatchingStatement) {
1140       reportPluralMisuseError(ME);
1141     }
1142   }
1143   return true;
1144 }
1145 
1146 /// Override TraverseIfStmt so we know when we are done traversing an IfStmt
1147 bool PluralMisuseChecker::MethodCrawler::TraverseIfStmt(IfStmt *I) {
1148   RecursiveASTVisitor<MethodCrawler>::TraverseIfStmt(I);
1149   return EndVisitIfStmt(I);
1150 }
1151 
1152 // EndVisit callbacks are not provided by the RecursiveASTVisitor
1153 // so we override TraverseIfStmt and make a call to EndVisitIfStmt
1154 // after traversing the IfStmt
1155 bool PluralMisuseChecker::MethodCrawler::EndVisitIfStmt(IfStmt *I) {
1156   MatchingStatements.pop_back();
1157   if (!MatchingStatements.empty()) {
1158     if (MatchingStatements.back() != nullptr) {
1159       InMatchingStatement = true;
1160       return true;
1161     }
1162   }
1163   InMatchingStatement = false;
1164   return true;
1165 }
1166 
1167 bool PluralMisuseChecker::MethodCrawler::VisitIfStmt(const IfStmt *I) {
1168   const Expr *Condition = I->getCond()->IgnoreParenImpCasts();
1169   if (isCheckingPlurality(Condition)) {
1170     MatchingStatements.push_back(I);
1171     InMatchingStatement = true;
1172   } else {
1173     MatchingStatements.push_back(nullptr);
1174     InMatchingStatement = false;
1175   }
1176 
1177   return true;
1178 }
1179 
1180 // Preliminary support for conditional operators.
1181 bool PluralMisuseChecker::MethodCrawler::TraverseConditionalOperator(
1182     ConditionalOperator *C) {
1183   RecursiveASTVisitor<MethodCrawler>::TraverseConditionalOperator(C);
1184   MatchingStatements.pop_back();
1185   if (!MatchingStatements.empty()) {
1186     if (MatchingStatements.back() != nullptr)
1187       InMatchingStatement = true;
1188     else
1189       InMatchingStatement = false;
1190   } else {
1191     InMatchingStatement = false;
1192   }
1193   return true;
1194 }
1195 
1196 bool PluralMisuseChecker::MethodCrawler::VisitConditionalOperator(
1197     const ConditionalOperator *C) {
1198   const Expr *Condition = C->getCond()->IgnoreParenImpCasts();
1199   if (isCheckingPlurality(Condition)) {
1200     MatchingStatements.push_back(C);
1201     InMatchingStatement = true;
1202   } else {
1203     MatchingStatements.push_back(nullptr);
1204     InMatchingStatement = false;
1205   }
1206   return true;
1207 }
1208 
1209 void PluralMisuseChecker::MethodCrawler::reportPluralMisuseError(
1210     const Stmt *S) const {
1211   // Generate the bug report.
1212   BR.EmitBasicReport(AC->getDecl(), Checker, "Plural Misuse",
1213                      "Localizability Issue (Apple)",
1214                      "Plural cases are not supported accross all languages. "
1215                      "Use a .stringsdict file instead",
1216                      PathDiagnosticLocation(S, BR.getSourceManager(), AC));
1217 }
1218 
1219 //===----------------------------------------------------------------------===//
1220 // Checker registration.
1221 //===----------------------------------------------------------------------===//
1222 
1223 void ento::registerNonLocalizedStringChecker(CheckerManager &mgr) {
1224   NonLocalizedStringChecker *checker =
1225       mgr.registerChecker<NonLocalizedStringChecker>();
1226   checker->IsAggressive =
1227       mgr.getAnalyzerOptions().getBooleanOption("AggressiveReport", false);
1228 }
1229 
1230 void ento::registerEmptyLocalizationContextChecker(CheckerManager &mgr) {
1231   mgr.registerChecker<EmptyLocalizationContextChecker>();
1232 }
1233 
1234 void ento::registerPluralMisuseChecker(CheckerManager &mgr) {
1235   mgr.registerChecker<PluralMisuseChecker>();
1236 }
1237