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