clang/lib/Analysis/RetainSummaryManager.cpp

   1 //== RetainSummaryManager.cpp - Summaries for reference counting --*- C++ -*--//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 //  This file defines summaries implementation for retain counting, which
  10 //  implements a reference count checker for Core Foundation, Cocoa
  11 //  and OSObject (on Mac OS X).
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
  16 #include "clang/Analysis/RetainSummaryManager.h"
  17 #include "clang/AST/Attr.h"
  18 #include "clang/AST/DeclCXX.h"
  19 #include "clang/AST/DeclObjC.h"
  20 #include "clang/AST/ParentMap.h"
  21 #include "clang/ASTMatchers/ASTMatchFinder.h"
  22 #include <optional>
  23
  24 using namespace clang;
  25 using namespace ento;
  26
  27 template <class T>
  28 constexpr static bool isOneOf() {
  29   return false;
  30 }
  31
  32 /// Helper function to check whether the class is one of the
  33 /// rest of varargs.
  34 template <class T, class P, class... ToCompare>
  35 constexpr static bool isOneOf() {
  36   return std::is_same_v<T, P> || isOneOf<T, ToCompare...>();
  37 }
  38
  39 namespace {
  40
  41 /// Fake attribute class for RC* attributes.
  42 struct GeneralizedReturnsRetainedAttr {
  43   static bool classof(const Attr *A) {
  44     if (auto AA = dyn_cast<AnnotateAttr>(A))
  45       return AA->getAnnotation() == "rc_ownership_returns_retained";
  46     return false;
  47   }
  48 };
  49
  50 struct GeneralizedReturnsNotRetainedAttr {
  51   static bool classof(const Attr *A) {
  52     if (auto AA = dyn_cast<AnnotateAttr>(A))
  53       return AA->getAnnotation() == "rc_ownership_returns_not_retained";
  54     return false;
  55   }
  56 };
  57
  58 struct GeneralizedConsumedAttr {
  59   static bool classof(const Attr *A) {
  60     if (auto AA = dyn_cast<AnnotateAttr>(A))
  61       return AA->getAnnotation() == "rc_ownership_consumed";
  62     return false;
  63   }
  64 };
  65
  66 }
  67
  68 template <class T>
  69 std::optional<ObjKind> RetainSummaryManager::hasAnyEnabledAttrOf(const Decl *D,
  70                                                                  QualType QT) {
  71   ObjKind K;
  72   if (isOneOf<T, CFConsumedAttr, CFReturnsRetainedAttr,
  73               CFReturnsNotRetainedAttr>()) {
  74     if (!TrackObjCAndCFObjects)
  75       return std::nullopt;
  76
  77     K = ObjKind::CF;
  78   } else if (isOneOf<T, NSConsumedAttr, NSConsumesSelfAttr,
  79                      NSReturnsAutoreleasedAttr, NSReturnsRetainedAttr,
  80                      NSReturnsNotRetainedAttr, NSConsumesSelfAttr>()) {
  81
  82     if (!TrackObjCAndCFObjects)
  83       return std::nullopt;
  84
  85     if (isOneOf<T, NSReturnsRetainedAttr, NSReturnsAutoreleasedAttr,
  86                 NSReturnsNotRetainedAttr>() &&
  87         !cocoa::isCocoaObjectRef(QT))
  88       return std::nullopt;
  89     K = ObjKind::ObjC;
  90   } else if (isOneOf<T, OSConsumedAttr, OSConsumesThisAttr,
  91                      OSReturnsNotRetainedAttr, OSReturnsRetainedAttr,
  92                      OSReturnsRetainedOnZeroAttr,
  93                      OSReturnsRetainedOnNonZeroAttr>()) {
  94     if (!TrackOSObjects)
  95       return std::nullopt;
  96     K = ObjKind::OS;
  97   } else if (isOneOf<T, GeneralizedReturnsNotRetainedAttr,
  98                      GeneralizedReturnsRetainedAttr,
  99                      GeneralizedConsumedAttr>()) {
 100     K = ObjKind::Generalized;
 101   } else {
 102     llvm_unreachable("Unexpected attribute");
 103   }
 104   if (D->hasAttr<T>())
 105     return K;
 106   return std::nullopt;
 107 }
 108
 109 template <class T1, class T2, class... Others>
 110 std::optional<ObjKind> RetainSummaryManager::hasAnyEnabledAttrOf(const Decl *D,
 111                                                                  QualType QT) {
 112   if (auto Out = hasAnyEnabledAttrOf<T1>(D, QT))
 113     return Out;
 114   return hasAnyEnabledAttrOf<T2, Others...>(D, QT);
 115 }
 116
 117 const RetainSummary *
 118 RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) {
 119   // Unique "simple" summaries -- those without ArgEffects.
 120   if (OldSumm.isSimple()) {
 121     ::llvm::FoldingSetNodeID ID;
 122     OldSumm.Profile(ID);
 123
 124     void *Pos;
 125     CachedSummaryNode *N = SimpleSummaries.FindNodeOrInsertPos(ID, Pos);
 126
 127     if (!N) {
 128       N = (CachedSummaryNode *) BPAlloc.Allocate<CachedSummaryNode>();
 129       new (N) CachedSummaryNode(OldSumm);
 130       SimpleSummaries.InsertNode(N, Pos);
 131     }
 132
 133     return &N->getValue();
 134   }
 135
 136   RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>();
 137   new (Summ) RetainSummary(OldSumm);
 138   return Summ;
 139 }
 140
 141 static bool isSubclass(const Decl *D,
 142                        StringRef ClassName) {
 143   using namespace ast_matchers;
 144   DeclarationMatcher SubclassM =
 145       cxxRecordDecl(isSameOrDerivedFrom(std::string(ClassName)));
 146   return !(match(SubclassM, *D, D->getASTContext()).empty());
 147 }
 148
 149 static bool isExactClass(const Decl *D, StringRef ClassName) {
 150   using namespace ast_matchers;
 151   DeclarationMatcher sameClassM =
 152       cxxRecordDecl(hasName(std::string(ClassName)));
 153   return !(match(sameClassM, *D, D->getASTContext()).empty());
 154 }
 155
 156 static bool isOSObjectSubclass(const Decl *D) {
 157   return D && isSubclass(D, "OSMetaClassBase") &&
 158          !isExactClass(D, "OSMetaClass");
 159 }
 160
 161 static bool isOSObjectDynamicCast(StringRef S) { return S == "safeMetaCast"; }
 162
 163 static bool isOSObjectRequiredCast(StringRef S) {
 164   return S == "requiredMetaCast";
 165 }
 166
 167 static bool isOSObjectThisCast(StringRef S) {
 168   return S == "metaCast";
 169 }
 170
 171
 172 static bool isOSObjectPtr(QualType QT) {
 173   return isOSObjectSubclass(QT->getPointeeCXXRecordDecl());
 174 }
 175
 176 static bool isISLObjectRef(QualType Ty) {
 177   return StringRef(Ty.getAsString()).startswith("isl_");
 178 }
 179
 180 static bool isOSIteratorSubclass(const Decl *D) {
 181   return isSubclass(D, "OSIterator");
 182 }
 183
 184 static bool hasRCAnnotation(const Decl *D, StringRef rcAnnotation) {
 185   for (const auto *Ann : D->specific_attrs<AnnotateAttr>()) {
 186     if (Ann->getAnnotation() == rcAnnotation)
 187       return true;
 188   }
 189   return false;
 190 }
 191
 192 static bool isRetain(const FunctionDecl *FD, StringRef FName) {
 193   return FName.startswith_insensitive("retain") ||
 194          FName.endswith_insensitive("retain");
 195 }
 196
 197 static bool isRelease(const FunctionDecl *FD, StringRef FName) {
 198   return FName.startswith_insensitive("release") ||
 199          FName.endswith_insensitive("release");
 200 }
 201
 202 static bool isAutorelease(const FunctionDecl *FD, StringRef FName) {
 203   return FName.startswith_insensitive("autorelease") ||
 204          FName.endswith_insensitive("autorelease");
 205 }
 206
 207 static bool isMakeCollectable(StringRef FName) {
 208   return FName.contains_insensitive("MakeCollectable");
 209 }
 210
 211 /// A function is OSObject related if it is declared on a subclass
 212 /// of OSObject, or any of the parameters is a subclass of an OSObject.
 213 static bool isOSObjectRelated(const CXXMethodDecl *MD) {
 214   if (isOSObjectSubclass(MD->getParent()))
 215     return true;
 216
 217   for (ParmVarDecl *Param : MD->parameters()) {
 218     QualType PT = Param->getType()->getPointeeType();
 219     if (!PT.isNull())
 220       if (CXXRecordDecl *RD = PT->getAsCXXRecordDecl())
 221         if (isOSObjectSubclass(RD))
 222           return true;
 223   }
 224
 225   return false;
 226 }
 227
 228 bool
 229 RetainSummaryManager::isKnownSmartPointer(QualType QT) {
 230   QT = QT.getCanonicalType();
 231   const auto *RD = QT->getAsCXXRecordDecl();
 232   if (!RD)
 233     return false;
 234   const IdentifierInfo *II = RD->getIdentifier();
 235   if (II && II->getName() == "smart_ptr")
 236     if (const auto *ND = dyn_cast<NamespaceDecl>(RD->getDeclContext()))
 237       if (ND->getNameAsString() == "os")
 238         return true;
 239   return false;
 240 }
 241
 242 const RetainSummary *
 243 RetainSummaryManager::getSummaryForOSObject(const FunctionDecl *FD,
 244                                             StringRef FName, QualType RetTy) {
 245   assert(TrackOSObjects &&
 246          "Requesting a summary for an OSObject but OSObjects are not tracked");
 247
 248   if (RetTy->isPointerType()) {
 249     const CXXRecordDecl *PD = RetTy->getPointeeType()->getAsCXXRecordDecl();
 250     if (PD && isOSObjectSubclass(PD)) {
 251       if (isOSObjectDynamicCast(FName) || isOSObjectRequiredCast(FName) ||
 252           isOSObjectThisCast(FName))
 253         return getDefaultSummary();
 254
 255       // TODO: Add support for the slightly common *Matching(table) idiom.
 256       // Cf. IOService::nameMatching() etc. - these function have an unusual
 257       // contract of returning at +0 or +1 depending on their last argument.
 258       if (FName.endswith("Matching")) {
 259         return getPersistentStopSummary();
 260       }
 261
 262       // All objects returned with functions *not* starting with 'get',
 263       // or iterators, are returned at +1.
 264       if ((!FName.startswith("get") && !FName.startswith("Get")) ||
 265           isOSIteratorSubclass(PD)) {
 266         return getOSSummaryCreateRule(FD);
 267       } else {
 268         return getOSSummaryGetRule(FD);
 269       }
 270     }
 271   }
 272
 273   if (const auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
 274     const CXXRecordDecl *Parent = MD->getParent();
 275     if (Parent && isOSObjectSubclass(Parent)) {
 276       if (FName == "release" || FName == "taggedRelease")
 277         return getOSSummaryReleaseRule(FD);
 278
 279       if (FName == "retain" || FName == "taggedRetain")
 280         return getOSSummaryRetainRule(FD);
 281
 282       if (FName == "free")
 283         return getOSSummaryFreeRule(FD);
 284
 285       if (MD->getOverloadedOperator() == OO_New)
 286         return getOSSummaryCreateRule(MD);
 287     }
 288   }
 289
 290   return nullptr;
 291 }
 292
 293 const RetainSummary *RetainSummaryManager::getSummaryForObjCOrCFObject(
 294     const FunctionDecl *FD,
 295     StringRef FName,
 296     QualType RetTy,
 297     const FunctionType *FT,
 298     bool &AllowAnnotations) {
 299
 300   ArgEffects ScratchArgs(AF.getEmptyMap());
 301
 302   std::string RetTyName = RetTy.getAsString();
 303   if (FName == "pthread_create" || FName == "pthread_setspecific") {
 304     // Part of: <rdar://problem/7299394> and <rdar://problem/11282706>.
 305     // This will be addressed better with IPA.
 306     return getPersistentStopSummary();
 307   } else if(FName == "NSMakeCollectable") {
 308     // Handle: id NSMakeCollectable(CFTypeRef)
 309     AllowAnnotations = false;
 310     return RetTy->isObjCIdType() ? getUnarySummary(FT, DoNothing)
 311                                  : getPersistentStopSummary();
 312   } else if (FName == "CMBufferQueueDequeueAndRetain" ||
 313              FName == "CMBufferQueueDequeueIfDataReadyAndRetain") {
 314     // Part of: <rdar://problem/39390714>.
 315     return getPersistentSummary(RetEffect::MakeOwned(ObjKind::CF),
 316                                 ScratchArgs,
 317                                 ArgEffect(DoNothing),
 318                                 ArgEffect(DoNothing));
 319   } else if (FName == "CFPlugInInstanceCreate") {
 320     return getPersistentSummary(RetEffect::MakeNoRet(), ScratchArgs);
 321   } else if (FName == "IORegistryEntrySearchCFProperty" ||
 322              (RetTyName == "CFMutableDictionaryRef" &&
 323               (FName == "IOBSDNameMatching" || FName == "IOServiceMatching" ||
 324                FName == "IOServiceNameMatching" ||
 325                FName == "IORegistryEntryIDMatching" ||
 326                FName == "IOOpenFirmwarePathMatching"))) {
 327     // Part of <rdar://problem/6961230>. (IOKit)
 328     // This should be addressed using a API table.
 329     return getPersistentSummary(RetEffect::MakeOwned(ObjKind::CF), ScratchArgs,
 330                                 ArgEffect(DoNothing), ArgEffect(DoNothing));
 331   } else if (FName == "IOServiceGetMatchingService" ||
 332              FName == "IOServiceGetMatchingServices") {
 333     // FIXES: <rdar://problem/6326900>
 334     // This should be addressed using a API table.  This strcmp is also
 335     // a little gross, but there is no need to super optimize here.
 336     ScratchArgs = AF.add(ScratchArgs, 1, ArgEffect(DecRef, ObjKind::CF));
 337     return getPersistentSummary(RetEffect::MakeNoRet(),
 338                                 ScratchArgs,
 339                                 ArgEffect(DoNothing), ArgEffect(DoNothing));
 340   } else if (FName == "IOServiceAddNotification" ||
 341              FName == "IOServiceAddMatchingNotification") {
 342     // Part of <rdar://problem/6961230>. (IOKit)
 343     // This should be addressed using a API table.
 344     ScratchArgs = AF.add(ScratchArgs, 2, ArgEffect(DecRef, ObjKind::CF));
 345     return getPersistentSummary(RetEffect::MakeNoRet(),
 346                                 ScratchArgs,
 347                                 ArgEffect(DoNothing), ArgEffect(DoNothing));
 348   } else if (FName == "CVPixelBufferCreateWithBytes") {
 349     // FIXES: <rdar://problem/7283567>
 350     // Eventually this can be improved by recognizing that the pixel
 351     // buffer passed to CVPixelBufferCreateWithBytes is released via
 352     // a callback and doing full IPA to make sure this is done correctly.
 353     // FIXME: This function has an out parameter that returns an
 354     // allocated object.
 355     ScratchArgs = AF.add(ScratchArgs, 7, ArgEffect(StopTracking));
 356     return getPersistentSummary(RetEffect::MakeNoRet(),
 357                                 ScratchArgs,
 358                                 ArgEffect(DoNothing), ArgEffect(DoNothing));
 359   } else if (FName == "CGBitmapContextCreateWithData") {
 360     // FIXES: <rdar://problem/7358899>
 361     // Eventually this can be improved by recognizing that 'releaseInfo'
 362     // passed to CGBitmapContextCreateWithData is released via
 363     // a callback and doing full IPA to make sure this is done correctly.
 364     ScratchArgs = AF.add(ScratchArgs, 8, ArgEffect(ArgEffect(StopTracking)));
 365     return getPersistentSummary(RetEffect::MakeOwned(ObjKind::CF), ScratchArgs,
 366                                 ArgEffect(DoNothing), ArgEffect(DoNothing));
 367   } else if (FName == "CVPixelBufferCreateWithPlanarBytes") {
 368     // FIXES: <rdar://problem/7283567>
 369     // Eventually this can be improved by recognizing that the pixel
 370     // buffer passed to CVPixelBufferCreateWithPlanarBytes is released
 371     // via a callback and doing full IPA to make sure this is done
 372     // correctly.
 373     ScratchArgs = AF.add(ScratchArgs, 12, ArgEffect(StopTracking));
 374     return getPersistentSummary(RetEffect::MakeNoRet(),
 375                                 ScratchArgs,
 376                                 ArgEffect(DoNothing), ArgEffect(DoNothing));
 377   } else if (FName == "VTCompressionSessionEncodeFrame") {
 378     // The context argument passed to VTCompressionSessionEncodeFrame()
 379     // is passed to the callback specified when creating the session
 380     // (e.g. with VTCompressionSessionCreate()) which can release it.
 381     // To account for this possibility, conservatively stop tracking
 382     // the context.
 383     ScratchArgs = AF.add(ScratchArgs, 5, ArgEffect(StopTracking));
 384     return getPersistentSummary(RetEffect::MakeNoRet(),
 385                                 ScratchArgs,
 386                                 ArgEffect(DoNothing), ArgEffect(DoNothing));
 387   } else if (FName == "dispatch_set_context" ||
 388              FName == "xpc_connection_set_context") {
 389     // <rdar://problem/11059275> - The analyzer currently doesn't have
 390     // a good way to reason about the finalizer function for libdispatch.
 391     // If we pass a context object that is memory managed, stop tracking it.
 392     // <rdar://problem/13783514> - Same problem, but for XPC.
 393     // FIXME: this hack should possibly go away once we can handle
 394     // libdispatch and XPC finalizers.
 395     ScratchArgs = AF.add(ScratchArgs, 1, ArgEffect(StopTracking));
 396     return getPersistentSummary(RetEffect::MakeNoRet(),
 397                                 ScratchArgs,
 398                                 ArgEffect(DoNothing), ArgEffect(DoNothing));
 399   } else if (FName.startswith("NSLog")) {
 400     return getDoNothingSummary();
 401   } else if (FName.startswith("NS") && FName.contains("Insert")) {
 402     // Allowlist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can
 403     // be deallocated by NSMapRemove. (radar://11152419)
 404     ScratchArgs = AF.add(ScratchArgs, 1, ArgEffect(StopTracking));
 405     ScratchArgs = AF.add(ScratchArgs, 2, ArgEffect(StopTracking));
 406     return getPersistentSummary(RetEffect::MakeNoRet(),
 407                                 ScratchArgs, ArgEffect(DoNothing),
 408                                 ArgEffect(DoNothing));
 409   }
 410
 411   if (RetTy->isPointerType()) {
 412
 413     // For CoreFoundation ('CF') types.
 414     if (cocoa::isRefType(RetTy, "CF", FName)) {
 415       if (isRetain(FD, FName)) {
 416         // CFRetain isn't supposed to be annotated. However, this may as
 417         // well be a user-made "safe" CFRetain function that is incorrectly
 418         // annotated as cf_returns_retained due to lack of better options.
 419         // We want to ignore such annotation.
 420         AllowAnnotations = false;
 421
 422         return getUnarySummary(FT, IncRef);
 423       } else if (isAutorelease(FD, FName)) {
 424         // The headers use cf_consumed, but we can fully model CFAutorelease
 425         // ourselves.
 426         AllowAnnotations = false;
 427
 428         return getUnarySummary(FT, Autorelease);
 429       } else if (isMakeCollectable(FName)) {
 430         AllowAnnotations = false;
 431         return getUnarySummary(FT, DoNothing);
 432       } else {
 433         return getCFCreateGetRuleSummary(FD);
 434       }
 435     }
 436
 437     // For CoreGraphics ('CG') and CoreVideo ('CV') types.
 438     if (cocoa::isRefType(RetTy, "CG", FName) ||
 439         cocoa::isRefType(RetTy, "CV", FName)) {
 440       if (isRetain(FD, FName))
 441         return getUnarySummary(FT, IncRef);
 442       else
 443         return getCFCreateGetRuleSummary(FD);
 444     }
 445
 446     // For all other CF-style types, use the Create/Get
 447     // rule for summaries but don't support Retain functions
 448     // with framework-specific prefixes.
 449     if (coreFoundation::isCFObjectRef(RetTy)) {
 450       return getCFCreateGetRuleSummary(FD);
 451     }
 452
 453     if (FD->hasAttr<CFAuditedTransferAttr>()) {
 454       return getCFCreateGetRuleSummary(FD);
 455     }
 456   }
 457
 458   // Check for release functions, the only kind of functions that we care
 459   // about that don't return a pointer type.
 460   if (FName.startswith("CG") || FName.startswith("CF")) {
 461     // Test for 'CGCF'.
 462     FName = FName.substr(FName.startswith("CGCF") ? 4 : 2);
 463
 464     if (isRelease(FD, FName))
 465       return getUnarySummary(FT, DecRef);
 466     else {
 467       assert(ScratchArgs.isEmpty());
 468       // Remaining CoreFoundation and CoreGraphics functions.
 469       // We use to assume that they all strictly followed the ownership idiom
 470       // and that ownership cannot be transferred.  While this is technically
 471       // correct, many methods allow a tracked object to escape.  For example:
 472       //
 473       //   CFMutableDictionaryRef x = CFDictionaryCreateMutable(...);
 474       //   CFDictionaryAddValue(y, key, x);
 475       //   CFRelease(x);
 476       //   ... it is okay to use 'x' since 'y' has a reference to it
 477       //
 478       // We handle this and similar cases with the follow heuristic.  If the
 479       // function name contains "InsertValue", "SetValue", "AddValue",
 480       // "AppendValue", or "SetAttribute", then we assume that arguments may
 481       // "escape."  This means that something else holds on to the object,
 482       // allowing it be used even after its local retain count drops to 0.
 483       ArgEffectKind E =
 484           (StrInStrNoCase(FName, "InsertValue") != StringRef::npos ||
 485            StrInStrNoCase(FName, "AddValue") != StringRef::npos ||
 486            StrInStrNoCase(FName, "SetValue") != StringRef::npos ||
 487            StrInStrNoCase(FName, "AppendValue") != StringRef::npos ||
 488            StrInStrNoCase(FName, "SetAttribute") != StringRef::npos)
 489               ? MayEscape
 490               : DoNothing;
 491
 492       return getPersistentSummary(RetEffect::MakeNoRet(), ScratchArgs,
 493                                   ArgEffect(DoNothing), ArgEffect(E, ObjKind::CF));
 494     }
 495   }
 496
 497   return nullptr;
 498 }
 499
 500 const RetainSummary *
 501 RetainSummaryManager::generateSummary(const FunctionDecl *FD,
 502                                       bool &AllowAnnotations) {
 503   // We generate "stop" summaries for implicitly defined functions.
 504   if (FD->isImplicit())
 505     return getPersistentStopSummary();
 506
 507   const IdentifierInfo *II = FD->getIdentifier();
 508
 509   StringRef FName = II ? II->getName() : "";
 510
 511   // Strip away preceding '_'.  Doing this here will effect all the checks
 512   // down below.
 513   FName = FName.substr(FName.find_first_not_of('_'));
 514
 515   // Inspect the result type. Strip away any typedefs.
 516   const auto *FT = FD->getType()->castAs<FunctionType>();
 517   QualType RetTy = FT->getReturnType();
 518
 519   if (TrackOSObjects)
 520     if (const RetainSummary *S = getSummaryForOSObject(FD, FName, RetTy))
 521       return S;
 522
 523   if (const auto *MD = dyn_cast<CXXMethodDecl>(FD))
 524     if (!isOSObjectRelated(MD))
 525       return getPersistentSummary(RetEffect::MakeNoRet(),
 526                                   ArgEffects(AF.getEmptyMap()),
 527                                   ArgEffect(DoNothing),
 528                                   ArgEffect(StopTracking),
 529                                   ArgEffect(DoNothing));
 530
 531   if (TrackObjCAndCFObjects)
 532     if (const RetainSummary *S =
 533             getSummaryForObjCOrCFObject(FD, FName, RetTy, FT, AllowAnnotations))
 534       return S;
 535
 536   return getDefaultSummary();
 537 }
 538
 539 const RetainSummary *
 540 RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) {
 541   // If we don't know what function we're calling, use our default summary.
 542   if (!FD)
 543     return getDefaultSummary();
 544
 545   // Look up a summary in our cache of FunctionDecls -> Summaries.
 546   FuncSummariesTy::iterator I = FuncSummaries.find(FD);
 547   if (I != FuncSummaries.end())
 548     return I->second;
 549
 550   // No summary?  Generate one.
 551   bool AllowAnnotations = true;
 552   const RetainSummary *S = generateSummary(FD, AllowAnnotations);
 553
 554   // Annotations override defaults.
 555   if (AllowAnnotations)
 556     updateSummaryFromAnnotations(S, FD);
 557
 558   FuncSummaries[FD] = S;
 559   return S;
 560 }
 561
 562 //===----------------------------------------------------------------------===//
 563 // Summary creation for functions (largely uses of Core Foundation).
 564 //===----------------------------------------------------------------------===//
 565
 566 static ArgEffect getStopTrackingHardEquivalent(ArgEffect E) {
 567   switch (E.getKind()) {
 568   case DoNothing:
 569   case Autorelease:
 570   case DecRefBridgedTransferred:
 571   case IncRef:
 572   case UnretainedOutParameter:
 573   case RetainedOutParameter:
 574   case RetainedOutParameterOnZero:
 575   case RetainedOutParameterOnNonZero:
 576   case MayEscape:
 577   case StopTracking:
 578   case StopTrackingHard:
 579     return E.withKind(StopTrackingHard);
 580   case DecRef:
 581   case DecRefAndStopTrackingHard:
 582     return E.withKind(DecRefAndStopTrackingHard);
 583   case Dealloc:
 584     return E.withKind(Dealloc);
 585   }
 586
 587   llvm_unreachable("Unknown ArgEffect kind");
 588 }
 589
 590 const RetainSummary *
 591 RetainSummaryManager::updateSummaryForNonZeroCallbackArg(const RetainSummary *S,
 592                                                          AnyCall &C) {
 593   ArgEffect RecEffect = getStopTrackingHardEquivalent(S->getReceiverEffect());
 594   ArgEffect DefEffect = getStopTrackingHardEquivalent(S->getDefaultArgEffect());
 595
 596   ArgEffects ScratchArgs(AF.getEmptyMap());
 597   ArgEffects CustomArgEffects = S->getArgEffects();
 598   for (ArgEffects::iterator I = CustomArgEffects.begin(),
 599                             E = CustomArgEffects.end();
 600        I != E; ++I) {
 601     ArgEffect Translated = getStopTrackingHardEquivalent(I->second);
 602     if (Translated.getKind() != DefEffect.getKind())
 603       ScratchArgs = AF.add(ScratchArgs, I->first, Translated);
 604   }
 605
 606   RetEffect RE = RetEffect::MakeNoRetHard();
 607
 608   // Special cases where the callback argument CANNOT free the return value.
 609   // This can generally only happen if we know that the callback will only be
 610   // called when the return value is already being deallocated.
 611   if (const IdentifierInfo *Name = C.getIdentifier()) {
 612     // When the CGBitmapContext is deallocated, the callback here will free
 613     // the associated data buffer.
 614     // The callback in dispatch_data_create frees the buffer, but not
 615     // the data object.
 616     if (Name->isStr("CGBitmapContextCreateWithData") ||
 617         Name->isStr("dispatch_data_create"))
 618       RE = S->getRetEffect();
 619   }
 620
 621   return getPersistentSummary(RE, ScratchArgs, RecEffect, DefEffect);
 622 }
 623
 624 void RetainSummaryManager::updateSummaryForReceiverUnconsumedSelf(
 625     const RetainSummary *&S) {
 626
 627   RetainSummaryTemplate Template(S, *this);
 628
 629   Template->setReceiverEffect(ArgEffect(DoNothing));
 630   Template->setRetEffect(RetEffect::MakeNoRet());
 631 }
 632
 633
 634 void RetainSummaryManager::updateSummaryForArgumentTypes(
 635   const AnyCall &C, const RetainSummary *&RS) {
 636   RetainSummaryTemplate Template(RS, *this);
 637
 638   unsigned parm_idx = 0;
 639   for (auto pi = C.param_begin(), pe = C.param_end(); pi != pe;
 640        ++pi, ++parm_idx) {
 641     QualType QT = (*pi)->getType();
 642
 643     // Skip already created values.
 644     if (RS->getArgEffects().contains(parm_idx))
 645       continue;
 646
 647     ObjKind K = ObjKind::AnyObj;
 648
 649     if (isISLObjectRef(QT)) {
 650       K = ObjKind::Generalized;
 651     } else if (isOSObjectPtr(QT)) {
 652       K = ObjKind::OS;
 653     } else if (cocoa::isCocoaObjectRef(QT)) {
 654       K = ObjKind::ObjC;
 655     } else if (coreFoundation::isCFObjectRef(QT)) {
 656       K = ObjKind::CF;
 657     }
 658
 659     if (K != ObjKind::AnyObj)
 660       Template->addArg(AF, parm_idx,
 661                        ArgEffect(RS->getDefaultArgEffect().getKind(), K));
 662   }
 663 }
 664
 665 const RetainSummary *
 666 RetainSummaryManager::getSummary(AnyCall C,
 667                                  bool HasNonZeroCallbackArg,
 668                                  bool IsReceiverUnconsumedSelf,
 669                                  QualType ReceiverType) {
 670   const RetainSummary *Summ;
 671   switch (C.getKind()) {
 672   case AnyCall::Function:
 673   case AnyCall::Constructor:
 674   case AnyCall::InheritedConstructor:
 675   case AnyCall::Allocator:
 676   case AnyCall::Deallocator:
 677     Summ = getFunctionSummary(cast_or_null<FunctionDecl>(C.getDecl()));
 678     break;
 679   case AnyCall::Block:
 680   case AnyCall::Destructor:
 681     // FIXME: These calls are currently unsupported.
 682     return getPersistentStopSummary();
 683   case AnyCall::ObjCMethod: {
 684     const auto *ME = cast_or_null<ObjCMessageExpr>(C.getExpr());
 685     if (!ME) {
 686       Summ = getMethodSummary(cast<ObjCMethodDecl>(C.getDecl()));
 687     } else if (ME->isInstanceMessage()) {
 688       Summ = getInstanceMethodSummary(ME, ReceiverType);
 689     } else {
 690       Summ = getClassMethodSummary(ME);
 691     }
 692     break;
 693   }
 694   }
 695
 696   if (HasNonZeroCallbackArg)
 697     Summ = updateSummaryForNonZeroCallbackArg(Summ, C);
 698
 699   if (IsReceiverUnconsumedSelf)
 700     updateSummaryForReceiverUnconsumedSelf(Summ);
 701
 702   updateSummaryForArgumentTypes(C, Summ);
 703
 704   assert(Summ && "Unknown call type?");
 705   return Summ;
 706 }
 707
 708
 709 const RetainSummary *
 710 RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) {
 711   if (coreFoundation::followsCreateRule(FD))
 712     return getCFSummaryCreateRule(FD);
 713
 714   return getCFSummaryGetRule(FD);
 715 }
 716
 717 bool RetainSummaryManager::isTrustedReferenceCountImplementation(
 718     const Decl *FD) {
 719   return hasRCAnnotation(FD, "rc_ownership_trusted_implementation");
 720 }
 721
 722 std::optional<RetainSummaryManager::BehaviorSummary>
 723 RetainSummaryManager::canEval(const CallExpr *CE, const FunctionDecl *FD,
 724                               bool &hasTrustedImplementationAnnotation) {
 725
 726   IdentifierInfo *II = FD->getIdentifier();
 727   if (!II)
 728     return std::nullopt;
 729
 730   StringRef FName = II->getName();
 731   FName = FName.substr(FName.find_first_not_of('_'));
 732
 733   QualType ResultTy = CE->getCallReturnType(Ctx);
 734   if (ResultTy->isObjCIdType()) {
 735     if (II->isStr("NSMakeCollectable"))
 736       return BehaviorSummary::Identity;
 737   } else if (ResultTy->isPointerType()) {
 738     // Handle: (CF|CG|CV)Retain
 739     //         CFAutorelease
 740     // It's okay to be a little sloppy here.
 741     if (FName == "CMBufferQueueDequeueAndRetain" ||
 742         FName == "CMBufferQueueDequeueIfDataReadyAndRetain") {
 743       // Part of: <rdar://problem/39390714>.
 744       // These are not retain. They just return something and retain it.
 745       return std::nullopt;
 746     }
 747     if (CE->getNumArgs() == 1 &&
 748         (cocoa::isRefType(ResultTy, "CF", FName) ||
 749          cocoa::isRefType(ResultTy, "CG", FName) ||
 750          cocoa::isRefType(ResultTy, "CV", FName)) &&
 751         (isRetain(FD, FName) || isAutorelease(FD, FName) ||
 752          isMakeCollectable(FName)))
 753       return BehaviorSummary::Identity;
 754
 755     // safeMetaCast is called by OSDynamicCast.
 756     // We assume that OSDynamicCast is either an identity (cast is OK,
 757     // the input was non-zero),
 758     // or that it returns zero (when the cast failed, or the input
 759     // was zero).
 760     if (TrackOSObjects) {
 761       if (isOSObjectDynamicCast(FName) && FD->param_size() >= 1) {
 762         return BehaviorSummary::IdentityOrZero;
 763       } else if (isOSObjectRequiredCast(FName) && FD->param_size() >= 1) {
 764         return BehaviorSummary::Identity;
 765       } else if (isOSObjectThisCast(FName) && isa<CXXMethodDecl>(FD) &&
 766                  !cast<CXXMethodDecl>(FD)->isStatic()) {
 767         return BehaviorSummary::IdentityThis;
 768       }
 769     }
 770
 771     const FunctionDecl* FDD = FD->getDefinition();
 772     if (FDD && isTrustedReferenceCountImplementation(FDD)) {
 773       hasTrustedImplementationAnnotation = true;
 774       return BehaviorSummary::Identity;
 775     }
 776   }
 777
 778   if (const auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
 779     const CXXRecordDecl *Parent = MD->getParent();
 780     if (TrackOSObjects && Parent && isOSObjectSubclass(Parent))
 781       if (FName == "release" || FName == "retain")
 782         return BehaviorSummary::NoOp;
 783   }
 784
 785   return std::nullopt;
 786 }
 787
 788 const RetainSummary *
 789 RetainSummaryManager::getUnarySummary(const FunctionType* FT,
 790                                       ArgEffectKind AE) {
 791
 792   // Unary functions have no arg effects by definition.
 793   ArgEffects ScratchArgs(AF.getEmptyMap());
 794
 795   // Verify that this is *really* a unary function.  This can
 796   // happen if people do weird things.
 797   const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT);
 798   if (!FTP || FTP->getNumParams() != 1)
 799     return getPersistentStopSummary();
 800
 801   ArgEffect Effect(AE, ObjKind::CF);
 802
 803   ScratchArgs = AF.add(ScratchArgs, 0, Effect);
 804   return getPersistentSummary(RetEffect::MakeNoRet(),
 805                               ScratchArgs,
 806                               ArgEffect(DoNothing), ArgEffect(DoNothing));
 807 }
 808
 809 const RetainSummary *
 810 RetainSummaryManager::getOSSummaryRetainRule(const FunctionDecl *FD) {
 811   return getPersistentSummary(RetEffect::MakeNoRet(),
 812                               AF.getEmptyMap(),
 813                               /*ReceiverEff=*/ArgEffect(DoNothing),
 814                               /*DefaultEff=*/ArgEffect(DoNothing),
 815                               /*ThisEff=*/ArgEffect(IncRef, ObjKind::OS));
 816 }
 817
 818 const RetainSummary *
 819 RetainSummaryManager::getOSSummaryReleaseRule(const FunctionDecl *FD) {
 820   return getPersistentSummary(RetEffect::MakeNoRet(),
 821                               AF.getEmptyMap(),
 822                               /*ReceiverEff=*/ArgEffect(DoNothing),
 823                               /*DefaultEff=*/ArgEffect(DoNothing),
 824                               /*ThisEff=*/ArgEffect(DecRef, ObjKind::OS));
 825 }
 826
 827 const RetainSummary *
 828 RetainSummaryManager::getOSSummaryFreeRule(const FunctionDecl *FD) {
 829   return getPersistentSummary(RetEffect::MakeNoRet(),
 830                               AF.getEmptyMap(),
 831                               /*ReceiverEff=*/ArgEffect(DoNothing),
 832                               /*DefaultEff=*/ArgEffect(DoNothing),
 833                               /*ThisEff=*/ArgEffect(Dealloc, ObjKind::OS));
 834 }
 835
 836 const RetainSummary *
 837 RetainSummaryManager::getOSSummaryCreateRule(const FunctionDecl *FD) {
 838   return getPersistentSummary(RetEffect::MakeOwned(ObjKind::OS),
 839                               AF.getEmptyMap());
 840 }
 841
 842 const RetainSummary *
 843 RetainSummaryManager::getOSSummaryGetRule(const FunctionDecl *FD) {
 844   return getPersistentSummary(RetEffect::MakeNotOwned(ObjKind::OS),
 845                               AF.getEmptyMap());
 846 }
 847
 848 const RetainSummary *
 849 RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) {
 850   return getPersistentSummary(RetEffect::MakeOwned(ObjKind::CF),
 851                               ArgEffects(AF.getEmptyMap()));
 852 }
 853
 854 const RetainSummary *
 855 RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) {
 856   return getPersistentSummary(RetEffect::MakeNotOwned(ObjKind::CF),
 857                               ArgEffects(AF.getEmptyMap()),
 858                               ArgEffect(DoNothing), ArgEffect(DoNothing));
 859 }
 860
 861
 862
 863
 864 //===----------------------------------------------------------------------===//
 865 // Summary creation for Selectors.
 866 //===----------------------------------------------------------------------===//
 867
 868 std::optional<RetEffect>
 869 RetainSummaryManager::getRetEffectFromAnnotations(QualType RetTy,
 870                                                   const Decl *D) {
 871   if (hasAnyEnabledAttrOf<NSReturnsRetainedAttr>(D, RetTy))
 872     return ObjCAllocRetE;
 873
 874   if (auto K = hasAnyEnabledAttrOf<CFReturnsRetainedAttr, OSReturnsRetainedAttr,
 875                                    GeneralizedReturnsRetainedAttr>(D, RetTy))
 876     return RetEffect::MakeOwned(*K);
 877
 878   if (auto K = hasAnyEnabledAttrOf<
 879           CFReturnsNotRetainedAttr, OSReturnsNotRetainedAttr,
 880           GeneralizedReturnsNotRetainedAttr, NSReturnsNotRetainedAttr,
 881           NSReturnsAutoreleasedAttr>(D, RetTy))
 882     return RetEffect::MakeNotOwned(*K);
 883
 884   if (const auto *MD = dyn_cast<CXXMethodDecl>(D))
 885     for (const auto *PD : MD->overridden_methods())
 886       if (auto RE = getRetEffectFromAnnotations(RetTy, PD))
 887         return RE;
 888
 889   return std::nullopt;
 890 }
 891
 892 /// \return Whether the chain of typedefs starting from @c QT
 893 /// has a typedef with a given name @c Name.
 894 static bool hasTypedefNamed(QualType QT,
 895                             StringRef Name) {
 896   while (auto *T = QT->getAs<TypedefType>()) {
 897     const auto &Context = T->getDecl()->getASTContext();
 898     if (T->getDecl()->getIdentifier() == &Context.Idents.get(Name))
 899       return true;
 900     QT = T->getDecl()->getUnderlyingType();
 901   }
 902   return false;
 903 }
 904
 905 static QualType getCallableReturnType(const NamedDecl *ND) {
 906   if (const auto *FD = dyn_cast<FunctionDecl>(ND)) {
 907     return FD->getReturnType();
 908   } else if (const auto *MD = dyn_cast<ObjCMethodDecl>(ND)) {
 909     return MD->getReturnType();
 910   } else {
 911     llvm_unreachable("Unexpected decl");
 912   }
 913 }
 914
 915 bool RetainSummaryManager::applyParamAnnotationEffect(
 916     const ParmVarDecl *pd, unsigned parm_idx, const NamedDecl *FD,
 917     RetainSummaryTemplate &Template) {
 918   QualType QT = pd->getType();
 919   if (auto K =
 920           hasAnyEnabledAttrOf<NSConsumedAttr, CFConsumedAttr, OSConsumedAttr,
 921                               GeneralizedConsumedAttr>(pd, QT)) {
 922     Template->addArg(AF, parm_idx, ArgEffect(DecRef, *K));
 923     return true;
 924   } else if (auto K = hasAnyEnabledAttrOf<
 925                  CFReturnsRetainedAttr, OSReturnsRetainedAttr,
 926                  OSReturnsRetainedOnNonZeroAttr, OSReturnsRetainedOnZeroAttr,
 927                  GeneralizedReturnsRetainedAttr>(pd, QT)) {
 928
 929     // For OSObjects, we try to guess whether the object is created based
 930     // on the return value.
 931     if (K == ObjKind::OS) {
 932       QualType QT = getCallableReturnType(FD);
 933
 934       bool HasRetainedOnZero = pd->hasAttr<OSReturnsRetainedOnZeroAttr>();
 935       bool HasRetainedOnNonZero = pd->hasAttr<OSReturnsRetainedOnNonZeroAttr>();
 936
 937       // The usual convention is to create an object on non-zero return, but
 938       // it's reverted if the typedef chain has a typedef kern_return_t,
 939       // because kReturnSuccess constant is defined as zero.
 940       // The convention can be overwritten by custom attributes.
 941       bool SuccessOnZero =
 942           HasRetainedOnZero ||
 943           (hasTypedefNamed(QT, "kern_return_t") && !HasRetainedOnNonZero);
 944       bool ShouldSplit = !QT.isNull() && !QT->isVoidType();
 945       ArgEffectKind AK = RetainedOutParameter;
 946       if (ShouldSplit && SuccessOnZero) {
 947         AK = RetainedOutParameterOnZero;
 948       } else if (ShouldSplit && (!SuccessOnZero || HasRetainedOnNonZero)) {
 949         AK = RetainedOutParameterOnNonZero;
 950       }
 951       Template->addArg(AF, parm_idx, ArgEffect(AK, ObjKind::OS));
 952     }
 953
 954     // For others:
 955     // Do nothing. Retained out parameters will either point to a +1 reference
 956     // or NULL, but the way you check for failure differs depending on the
 957     // API. Consequently, we don't have a good way to track them yet.
 958     return true;
 959   } else if (auto K = hasAnyEnabledAttrOf<CFReturnsNotRetainedAttr,
 960                                           OSReturnsNotRetainedAttr,
 961                                           GeneralizedReturnsNotRetainedAttr>(
 962                  pd, QT)) {
 963     Template->addArg(AF, parm_idx, ArgEffect(UnretainedOutParameter, *K));
 964     return true;
 965   }
 966
 967   if (const auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
 968     for (const auto *OD : MD->overridden_methods()) {
 969       const ParmVarDecl *OP = OD->parameters()[parm_idx];
 970       if (applyParamAnnotationEffect(OP, parm_idx, OD, Template))
 971         return true;
 972     }
 973   }
 974
 975   return false;
 976 }
 977
 978 void
 979 RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ,
 980                                                    const FunctionDecl *FD) {
 981   if (!FD)
 982     return;
 983
 984   assert(Summ && "Must have a summary to add annotations to.");
 985   RetainSummaryTemplate Template(Summ, *this);
 986
 987   // Effects on the parameters.
 988   unsigned parm_idx = 0;
 989   for (auto pi = FD->param_begin(),
 990          pe = FD->param_end(); pi != pe; ++pi, ++parm_idx)
 991     applyParamAnnotationEffect(*pi, parm_idx, FD, Template);
 992
 993   QualType RetTy = FD->getReturnType();
 994   if (std::optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, FD))
 995     Template->setRetEffect(*RetE);
 996
 997   if (hasAnyEnabledAttrOf<OSConsumesThisAttr>(FD, RetTy))
 998     Template->setThisEffect(ArgEffect(DecRef, ObjKind::OS));
 999 }
1000
1001 void
1002 RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ,
1003                                                    const ObjCMethodDecl *MD) {
1004   if (!MD)
1005     return;
1006
1007   assert(Summ && "Must have a valid summary to add annotations to");
1008   RetainSummaryTemplate Template(Summ, *this);
1009
1010   // Effects on the receiver.
1011   if (hasAnyEnabledAttrOf<NSConsumesSelfAttr>(MD, MD->getReturnType()))
1012     Template->setReceiverEffect(ArgEffect(DecRef, ObjKind::ObjC));
1013
1014   // Effects on the parameters.
1015   unsigned parm_idx = 0;
1016   for (auto pi = MD->param_begin(), pe = MD->param_end(); pi != pe;
1017        ++pi, ++parm_idx)
1018     applyParamAnnotationEffect(*pi, parm_idx, MD, Template);
1019
1020   QualType RetTy = MD->getReturnType();
1021   if (std::optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, MD))
1022     Template->setRetEffect(*RetE);
1023 }
1024
1025 const RetainSummary *
1026 RetainSummaryManager::getStandardMethodSummary(const ObjCMethodDecl *MD,
1027                                                Selector S, QualType RetTy) {
1028   // Any special effects?
1029   ArgEffect ReceiverEff = ArgEffect(DoNothing, ObjKind::ObjC);
1030   RetEffect ResultEff = RetEffect::MakeNoRet();
1031
1032   // Check the method family, and apply any default annotations.
1033   switch (MD ? MD->getMethodFamily() : S.getMethodFamily()) {
1034     case OMF_None:
1035     case OMF_initialize:
1036     case OMF_performSelector:
1037       // Assume all Objective-C methods follow Cocoa Memory Management rules.
1038       // FIXME: Does the non-threaded performSelector family really belong here?
1039       // The selector could be, say, @selector(copy).
1040       if (cocoa::isCocoaObjectRef(RetTy))
1041         ResultEff = RetEffect::MakeNotOwned(ObjKind::ObjC);
1042       else if (coreFoundation::isCFObjectRef(RetTy)) {
1043         // ObjCMethodDecl currently doesn't consider CF objects as valid return
1044         // values for alloc, new, copy, or mutableCopy, so we have to
1045         // double-check with the selector. This is ugly, but there aren't that
1046         // many Objective-C methods that return CF objects, right?
1047         if (MD) {
1048           switch (S.getMethodFamily()) {
1049           case OMF_alloc:
1050           case OMF_new:
1051           case OMF_copy:
1052           case OMF_mutableCopy:
1053             ResultEff = RetEffect::MakeOwned(ObjKind::CF);
1054             break;
1055           default:
1056             ResultEff = RetEffect::MakeNotOwned(ObjKind::CF);
1057             break;
1058           }
1059         } else {
1060           ResultEff = RetEffect::MakeNotOwned(ObjKind::CF);
1061         }
1062       }
1063       break;
1064     case OMF_init:
1065       ResultEff = ObjCInitRetE;
1066       ReceiverEff = ArgEffect(DecRef, ObjKind::ObjC);
1067       break;
1068     case OMF_alloc:
1069     case OMF_new:
1070     case OMF_copy:
1071     case OMF_mutableCopy:
1072       if (cocoa::isCocoaObjectRef(RetTy))
1073         ResultEff = ObjCAllocRetE;
1074       else if (coreFoundation::isCFObjectRef(RetTy))
1075         ResultEff = RetEffect::MakeOwned(ObjKind::CF);
1076       break;
1077     case OMF_autorelease:
1078       ReceiverEff = ArgEffect(Autorelease, ObjKind::ObjC);
1079       break;
1080     case OMF_retain:
1081       ReceiverEff = ArgEffect(IncRef, ObjKind::ObjC);
1082       break;
1083     case OMF_release:
1084       ReceiverEff = ArgEffect(DecRef, ObjKind::ObjC);
1085       break;
1086     case OMF_dealloc:
1087       ReceiverEff = ArgEffect(Dealloc, ObjKind::ObjC);
1088       break;
1089     case OMF_self:
1090       // -self is handled specially by the ExprEngine to propagate the receiver.
1091       break;
1092     case OMF_retainCount:
1093     case OMF_finalize:
1094       // These methods don't return objects.
1095       break;
1096   }
1097
1098   // If one of the arguments in the selector has the keyword 'delegate' we
1099   // should stop tracking the reference count for the receiver.  This is
1100   // because the reference count is quite possibly handled by a delegate
1101   // method.
1102   if (S.isKeywordSelector()) {
1103     for (unsigned i = 0, e = S.getNumArgs(); i != e; ++i) {
1104       StringRef Slot = S.getNameForSlot(i);
1105       if (Slot.substr(Slot.size() - 8).equals_insensitive("delegate")) {
1106         if (ResultEff == ObjCInitRetE)
1107           ResultEff = RetEffect::MakeNoRetHard();
1108         else
1109           ReceiverEff = ArgEffect(StopTrackingHard, ObjKind::ObjC);
1110       }
1111     }
1112   }
1113
1114   if (ReceiverEff.getKind() == DoNothing &&
1115       ResultEff.getKind() == RetEffect::NoRet)
1116     return getDefaultSummary();
1117
1118   return getPersistentSummary(ResultEff, ArgEffects(AF.getEmptyMap()),
1119                               ArgEffect(ReceiverEff), ArgEffect(MayEscape));
1120 }
1121
1122 const RetainSummary *
1123 RetainSummaryManager::getClassMethodSummary(const ObjCMessageExpr *ME) {
1124   assert(!ME->isInstanceMessage());
1125   const ObjCInterfaceDecl *Class = ME->getReceiverInterface();
1126
1127   return getMethodSummary(ME->getSelector(), Class, ME->getMethodDecl(),
1128                           ME->getType(), ObjCClassMethodSummaries);
1129 }
1130
1131 const RetainSummary *RetainSummaryManager::getInstanceMethodSummary(
1132     const ObjCMessageExpr *ME,
1133     QualType ReceiverType) {
1134   const ObjCInterfaceDecl *ReceiverClass = nullptr;
1135
1136   // We do better tracking of the type of the object than the core ExprEngine.
1137   // See if we have its type in our private state.
1138   if (!ReceiverType.isNull())
1139     if (const auto *PT = ReceiverType->getAs<ObjCObjectPointerType>())
1140       ReceiverClass = PT->getInterfaceDecl();
1141
1142   // If we don't know what kind of object this is, fall back to its static type.
1143   if (!ReceiverClass)
1144     ReceiverClass = ME->getReceiverInterface();
1145
1146   // FIXME: The receiver could be a reference to a class, meaning that
1147   //  we should use the class method.
1148   // id x = [NSObject class];
1149   // [x performSelector:... withObject:... afterDelay:...];
1150   Selector S = ME->getSelector();
1151   const ObjCMethodDecl *Method = ME->getMethodDecl();
1152   if (!Method && ReceiverClass)
1153     Method = ReceiverClass->getInstanceMethod(S);
1154
1155   return getMethodSummary(S, ReceiverClass, Method, ME->getType(),
1156                           ObjCMethodSummaries);
1157 }
1158
1159 const RetainSummary *
1160 RetainSummaryManager::getMethodSummary(Selector S,
1161                                        const ObjCInterfaceDecl *ID,
1162                                        const ObjCMethodDecl *MD, QualType RetTy,
1163                                        ObjCMethodSummariesTy &CachedSummaries) {
1164
1165   // Objective-C method summaries are only applicable to ObjC and CF objects.
1166   if (!TrackObjCAndCFObjects)
1167     return getDefaultSummary();
1168
1169   // Look up a summary in our summary cache.
1170   const RetainSummary *Summ = CachedSummaries.find(ID, S);
1171
1172   if (!Summ) {
1173     Summ = getStandardMethodSummary(MD, S, RetTy);
1174
1175     // Annotations override defaults.
1176     updateSummaryFromAnnotations(Summ, MD);
1177
1178     // Memoize the summary.
1179     CachedSummaries[ObjCSummaryKey(ID, S)] = Summ;
1180   }
1181
1182   return Summ;
1183 }
1184
1185 void RetainSummaryManager::InitializeClassMethodSummaries() {
1186   ArgEffects ScratchArgs = AF.getEmptyMap();
1187
1188   // Create the [NSAssertionHandler currentHander] summary.
1189   addClassMethSummary("NSAssertionHandler", "currentHandler",
1190                 getPersistentSummary(RetEffect::MakeNotOwned(ObjKind::ObjC),
1191                                      ScratchArgs));
1192
1193   // Create the [NSAutoreleasePool addObject:] summary.
1194   ScratchArgs = AF.add(ScratchArgs, 0, ArgEffect(Autorelease));
1195   addClassMethSummary("NSAutoreleasePool", "addObject",
1196                       getPersistentSummary(RetEffect::MakeNoRet(), ScratchArgs,
1197                                            ArgEffect(DoNothing),
1198                                            ArgEffect(Autorelease)));
1199 }
1200
1201 void RetainSummaryManager::InitializeMethodSummaries() {
1202
1203   ArgEffects ScratchArgs = AF.getEmptyMap();
1204   // Create the "init" selector.  It just acts as a pass-through for the
1205   // receiver.
1206   const RetainSummary *InitSumm = getPersistentSummary(
1207       ObjCInitRetE, ScratchArgs, ArgEffect(DecRef, ObjKind::ObjC));
1208   addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm);
1209
1210   // awakeAfterUsingCoder: behaves basically like an 'init' method.  It
1211   // claims the receiver and returns a retained object.
1212   addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx),
1213                          InitSumm);
1214
1215   // The next methods are allocators.
1216   const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE,
1217                                                         ScratchArgs);
1218   const RetainSummary *CFAllocSumm =
1219     getPersistentSummary(RetEffect::MakeOwned(ObjKind::CF), ScratchArgs);
1220
1221   // Create the "retain" selector.
1222   RetEffect NoRet = RetEffect::MakeNoRet();
1223   const RetainSummary *Summ = getPersistentSummary(
1224       NoRet, ScratchArgs, ArgEffect(IncRef, ObjKind::ObjC));
1225   addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ);
1226
1227   // Create the "release" selector.
1228   Summ = getPersistentSummary(NoRet, ScratchArgs,
1229                               ArgEffect(DecRef, ObjKind::ObjC));
1230   addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ);
1231
1232   // Create the -dealloc summary.
1233   Summ = getPersistentSummary(NoRet, ScratchArgs, ArgEffect(Dealloc,
1234                                                             ObjKind::ObjC));
1235   addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ);
1236
1237   // Create the "autorelease" selector.
1238   Summ = getPersistentSummary(NoRet, ScratchArgs, ArgEffect(Autorelease,
1239                                                             ObjKind::ObjC));
1240   addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ);
1241
1242   // For NSWindow, allocated objects are (initially) self-owned.
1243   // FIXME: For now we opt for false negatives with NSWindow, as these objects
1244   //  self-own themselves.  However, they only do this once they are displayed.
1245   //  Thus, we need to track an NSWindow's display status.
1246   //  This is tracked in <rdar://problem/6062711>.
1247   //  See also http://llvm.org/bugs/show_bug.cgi?id=3714.
1248   const RetainSummary *NoTrackYet =
1249       getPersistentSummary(RetEffect::MakeNoRet(), ScratchArgs,
1250                            ArgEffect(StopTracking), ArgEffect(StopTracking));
1251
1252   addClassMethSummary("NSWindow", "alloc", NoTrackYet);
1253
1254   // For NSPanel (which subclasses NSWindow), allocated objects are not
1255   //  self-owned.
1256   // FIXME: For now we don't track NSPanels. object for the same reason
1257   //   as for NSWindow objects.
1258   addClassMethSummary("NSPanel", "alloc", NoTrackYet);
1259
1260   // For NSNull, objects returned by +null are singletons that ignore
1261   // retain/release semantics.  Just don't track them.
1262   // <rdar://problem/12858915>
1263   addClassMethSummary("NSNull", "null", NoTrackYet);
1264
1265   // Don't track allocated autorelease pools, as it is okay to prematurely
1266   // exit a method.
1267   addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet);
1268   addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false);
1269   addClassMethSummary("NSAutoreleasePool", "new", NoTrackYet);
1270
1271   // Create summaries QCRenderer/QCView -createSnapShotImageOfType:
1272   addInstMethSummary("QCRenderer", AllocSumm, "createSnapshotImageOfType");
1273   addInstMethSummary("QCView", AllocSumm, "createSnapshotImageOfType");
1274
1275   // Create summaries for CIContext, 'createCGImage' and
1276   // 'createCGLayerWithSize'.  These objects are CF objects, and are not
1277   // automatically garbage collected.
1278   addInstMethSummary("CIContext", CFAllocSumm, "createCGImage", "fromRect");
1279   addInstMethSummary("CIContext", CFAllocSumm, "createCGImage", "fromRect",
1280                      "format", "colorSpace");
1281   addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", "info");
1282 }
1283
1284 const RetainSummary *
1285 RetainSummaryManager::getMethodSummary(const ObjCMethodDecl *MD) {
1286   const ObjCInterfaceDecl *ID = MD->getClassInterface();
1287   Selector S = MD->getSelector();
1288   QualType ResultTy = MD->getReturnType();
1289
1290   ObjCMethodSummariesTy *CachedSummaries;
1291   if (MD->isInstanceMethod())
1292     CachedSummaries = &ObjCMethodSummaries;
1293   else
1294     CachedSummaries = &ObjCClassMethodSummaries;
1295
1296   return getMethodSummary(S, ID, MD, ResultTy, *CachedSummaries);
1297 }