clang/lib/Analysis/CocoaConventions.cpp

   1 //===- CocoaConventions.h - Special handling of Cocoa conventions -*- 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 implements cocoa naming convention analysis.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
  14 #include "clang/AST/Decl.h"
  15 #include "clang/AST/DeclObjC.h"
  16 #include "clang/AST/Type.h"
  17 #include "clang/Basic/CharInfo.h"
  18 #include "llvm/ADT/StringExtras.h"
  19 #include "llvm/Support/ErrorHandling.h"
  20
  21 using namespace clang;
  22 using namespace ento;
  23
  24 bool cocoa::isRefType(QualType RetTy, StringRef Prefix,
  25                       StringRef Name) {
  26   // Recursively walk the typedef stack, allowing typedefs of reference types.
  27   while (const TypedefType *TD = RetTy->getAs<TypedefType>()) {
  28     StringRef TDName = TD->getDecl()->getIdentifier()->getName();
  29     if (TDName.startswith(Prefix) && TDName.endswith("Ref"))
  30       return true;
  31     // XPC unfortunately uses CF-style function names, but aren't CF types.
  32     if (TDName.startswith("xpc_"))
  33       return false;
  34     RetTy = TD->getDecl()->getUnderlyingType();
  35   }
  36
  37   if (Name.empty())
  38     return false;
  39
  40   // Is the type void*?
  41   const PointerType* PT = RetTy->castAs<PointerType>();
  42   if (!PT || !PT->getPointeeType().getUnqualifiedType()->isVoidType())
  43     return false;
  44
  45   // Does the name start with the prefix?
  46   return Name.startswith(Prefix);
  47 }
  48
  49 /// Returns true when the passed-in type is a CF-style reference-counted
  50 /// type from the DiskArbitration framework.
  51 static bool isDiskArbitrationAPIRefType(QualType T) {
  52   return cocoa::isRefType(T, "DADisk") ||
  53       cocoa::isRefType(T, "DADissenter") ||
  54       cocoa::isRefType(T, "DASessionRef");
  55 }
  56
  57 bool coreFoundation::isCFObjectRef(QualType T) {
  58   return cocoa::isRefType(T, "CF") || // Core Foundation.
  59          cocoa::isRefType(T, "CG") || // Core Graphics.
  60          cocoa::isRefType(T, "CM") || // Core Media.
  61          isDiskArbitrationAPIRefType(T);
  62 }
  63
  64
  65 bool cocoa::isCocoaObjectRef(QualType Ty) {
  66   if (!Ty->isObjCObjectPointerType())
  67     return false;
  68
  69   const ObjCObjectPointerType *PT = Ty->getAs<ObjCObjectPointerType>();
  70
  71   // Can be true for objects with the 'NSObject' attribute.
  72   if (!PT)
  73     return true;
  74
  75   // We assume that id<..>, id, Class, and Class<..> all represent tracked
  76   // objects.
  77   if (PT->isObjCIdType() || PT->isObjCQualifiedIdType() ||
  78       PT->isObjCClassType() || PT->isObjCQualifiedClassType())
  79     return true;
  80
  81   // Does the interface subclass NSObject?
  82   // FIXME: We can memoize here if this gets too expensive.
  83   const ObjCInterfaceDecl *ID = PT->getInterfaceDecl();
  84
  85   // Assume that anything declared with a forward declaration and no
  86   // @interface subclasses NSObject.
  87   if (!ID->hasDefinition())
  88     return true;
  89
  90   for ( ; ID ; ID = ID->getSuperClass())
  91     if (ID->getIdentifier()->getName() == "NSObject")
  92       return true;
  93
  94   return false;
  95 }
  96
  97 bool coreFoundation::followsCreateRule(const FunctionDecl *fn) {
  98   // For now, *just* base this on the function name, not on anything else.
  99
 100   const IdentifierInfo *ident = fn->getIdentifier();
 101   if (!ident) return false;
 102   StringRef functionName = ident->getName();
 103
 104   StringRef::iterator it = functionName.begin();
 105   StringRef::iterator start = it;
 106   StringRef::iterator endI = functionName.end();
 107
 108   while (true) {
 109     // Scan for the start of 'create' or 'copy'.
 110     for ( ; it != endI ; ++it) {
 111       // Search for the first character.  It can either be 'C' or 'c'.
 112       char ch = *it;
 113       if (ch == 'C' || ch == 'c') {
 114         // Make sure this isn't something like 'recreate' or 'Scopy'.
 115         if (ch == 'c' && it != start && isLetter(*(it - 1)))
 116           continue;
 117
 118         ++it;
 119         break;
 120       }
 121     }
 122
 123     // Did we hit the end of the string?  If so, we didn't find a match.
 124     if (it == endI)
 125       return false;
 126
 127     // Scan for *lowercase* 'reate' or 'opy', followed by no lowercase
 128     // character.
 129     StringRef suffix = functionName.substr(it - start);
 130     if (suffix.startswith("reate")) {
 131       it += 5;
 132     }
 133     else if (suffix.startswith("opy")) {
 134       it += 3;
 135     } else {
 136       // Keep scanning.
 137       continue;
 138     }
 139
 140     if (it == endI || !isLowercase(*it))
 141       return true;
 142
 143     // If we matched a lowercase character, it isn't the end of the
 144     // word.  Keep scanning.
 145   }
 146 }