1 //===--- SemaFixItUtils.cpp - Sema FixIts ---------------------------------===//
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 helper classes for generation of Sema FixItHints.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "clang/AST/ASTContext.h"
15 #include "clang/AST/ExprCXX.h"
16 #include "clang/AST/ExprObjC.h"
17 #include "clang/Lex/Preprocessor.h"
18 #include "clang/Sema/Sema.h"
19 #include "clang/Sema/SemaFixItUtils.h"
20
21 using namespace clang;
22
compareTypesSimple(CanQualType From,CanQualType To,Sema & S,SourceLocation Loc,ExprValueKind FromVK)23 bool ConversionFixItGenerator::compareTypesSimple(CanQualType From,
24 CanQualType To,
25 Sema &S,
26 SourceLocation Loc,
27 ExprValueKind FromVK) {
28 if (!To.isAtLeastAsQualifiedAs(From))
29 return false;
30
31 From = From.getNonReferenceType();
32 To = To.getNonReferenceType();
33
34 // If both are pointer types, work with the pointee types.
35 if (isa<PointerType>(From) && isa<PointerType>(To)) {
36 From = S.Context.getCanonicalType(
37 (cast<PointerType>(From))->getPointeeType());
38 To = S.Context.getCanonicalType(
39 (cast<PointerType>(To))->getPointeeType());
40 }
41
42 const CanQualType FromUnq = From.getUnqualifiedType();
43 const CanQualType ToUnq = To.getUnqualifiedType();
44
45 if ((FromUnq == ToUnq || (S.IsDerivedFrom(FromUnq, ToUnq)) ) &&
46 To.isAtLeastAsQualifiedAs(From))
47 return true;
48 return false;
49 }
50
tryToFixConversion(const Expr * FullExpr,const QualType FromTy,const QualType ToTy,Sema & S)51 bool ConversionFixItGenerator::tryToFixConversion(const Expr *FullExpr,
52 const QualType FromTy,
53 const QualType ToTy,
54 Sema &S) {
55 if (!FullExpr)
56 return false;
57
58 const CanQualType FromQTy = S.Context.getCanonicalType(FromTy);
59 const CanQualType ToQTy = S.Context.getCanonicalType(ToTy);
60 const SourceLocation Begin = FullExpr->getSourceRange().getBegin();
61 const SourceLocation End = S.PP.getLocForEndOfToken(FullExpr->getSourceRange()
62 .getEnd());
63
64 // Strip the implicit casts - those are implied by the compiler, not the
65 // original source code.
66 const Expr* Expr = FullExpr->IgnoreImpCasts();
67
68 bool NeedParen = true;
69 if (isa<ArraySubscriptExpr>(Expr) ||
70 isa<CallExpr>(Expr) ||
71 isa<DeclRefExpr>(Expr) ||
72 isa<CastExpr>(Expr) ||
73 isa<CXXNewExpr>(Expr) ||
74 isa<CXXConstructExpr>(Expr) ||
75 isa<CXXDeleteExpr>(Expr) ||
76 isa<CXXNoexceptExpr>(Expr) ||
77 isa<CXXPseudoDestructorExpr>(Expr) ||
78 isa<CXXScalarValueInitExpr>(Expr) ||
79 isa<CXXThisExpr>(Expr) ||
80 isa<CXXTypeidExpr>(Expr) ||
81 isa<CXXUnresolvedConstructExpr>(Expr) ||
82 isa<ObjCMessageExpr>(Expr) ||
83 isa<ObjCPropertyRefExpr>(Expr) ||
84 isa<ObjCProtocolExpr>(Expr) ||
85 isa<MemberExpr>(Expr) ||
86 isa<ParenExpr>(FullExpr) ||
87 isa<ParenListExpr>(Expr) ||
88 isa<SizeOfPackExpr>(Expr) ||
89 isa<UnaryOperator>(Expr))
90 NeedParen = false;
91
92 // Check if the argument needs to be dereferenced:
93 // (type * -> type) or (type * -> type &).
94 if (const PointerType *FromPtrTy = dyn_cast<PointerType>(FromQTy)) {
95 OverloadFixItKind FixKind = OFIK_Dereference;
96
97 bool CanConvert = CompareTypes(
98 S.Context.getCanonicalType(FromPtrTy->getPointeeType()), ToQTy,
99 S, Begin, VK_LValue);
100 if (CanConvert) {
101 // Do not suggest dereferencing a Null pointer.
102 if (Expr->IgnoreParenCasts()->
103 isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull))
104 return false;
105
106 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(Expr)) {
107 if (UO->getOpcode() == UO_AddrOf) {
108 FixKind = OFIK_RemoveTakeAddress;
109 Hints.push_back(FixItHint::CreateRemoval(
110 CharSourceRange::getTokenRange(Begin, Begin)));
111 }
112 } else if (NeedParen) {
113 Hints.push_back(FixItHint::CreateInsertion(Begin, "*("));
114 Hints.push_back(FixItHint::CreateInsertion(End, ")"));
115 } else {
116 Hints.push_back(FixItHint::CreateInsertion(Begin, "*"));
117 }
118
119 NumConversionsFixed++;
120 if (NumConversionsFixed == 1)
121 Kind = FixKind;
122 return true;
123 }
124 }
125
126 // Check if the pointer to the argument needs to be passed:
127 // (type -> type *) or (type & -> type *).
128 if (isa<PointerType>(ToQTy)) {
129 bool CanConvert = false;
130 OverloadFixItKind FixKind = OFIK_TakeAddress;
131
132 // Only suggest taking address of L-values.
133 if (!Expr->isLValue() || Expr->getObjectKind() != OK_Ordinary)
134 return false;
135
136 CanConvert = CompareTypes(S.Context.getPointerType(FromQTy), ToQTy,
137 S, Begin, VK_RValue);
138 if (CanConvert) {
139
140 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(Expr)) {
141 if (UO->getOpcode() == UO_Deref) {
142 FixKind = OFIK_RemoveDereference;
143 Hints.push_back(FixItHint::CreateRemoval(
144 CharSourceRange::getTokenRange(Begin, Begin)));
145 }
146 } else if (NeedParen) {
147 Hints.push_back(FixItHint::CreateInsertion(Begin, "&("));
148 Hints.push_back(FixItHint::CreateInsertion(End, ")"));
149 } else {
150 Hints.push_back(FixItHint::CreateInsertion(Begin, "&"));
151 }
152
153 NumConversionsFixed++;
154 if (NumConversionsFixed == 1)
155 Kind = FixKind;
156 return true;
157 }
158 }
159
160 return false;
161 }
162
isMacroDefined(const Sema & S,StringRef Name)163 static bool isMacroDefined(const Sema &S, StringRef Name) {
164 return S.PP.getMacroInfo(&S.getASTContext().Idents.get(Name));
165 }
166
getScalarZeroExpressionForType(const Type & T,const Sema & S)167 static std::string getScalarZeroExpressionForType(const Type& T, const Sema& S) {
168 assert(T.isScalarType() && "use scalar types only");
169 // Suggest "0" for non-enumeration scalar types, unless we can find a
170 // better initializer.
171 if (T.isEnumeralType())
172 return std::string();
173 if ((T.isObjCObjectPointerType() || T.isBlockPointerType()) &&
174 isMacroDefined(S, "nil"))
175 return "nil";
176 if (T.isRealFloatingType())
177 return "0.0";
178 if (T.isBooleanType() && S.LangOpts.CPlusPlus)
179 return "false";
180 if (T.isPointerType() || T.isMemberPointerType()) {
181 if (S.LangOpts.CPlusPlus0x)
182 return "nullptr";
183 if (isMacroDefined(S, "NULL"))
184 return "NULL";
185 }
186 if (T.isCharType())
187 return "'\\0'";
188 if (T.isWideCharType())
189 return "L'\\0'";
190 if (T.isChar16Type())
191 return "u'\\0'";
192 if (T.isChar32Type())
193 return "U'\\0'";
194 return "0";
195 }
196
getFixItZeroInitializerForType(QualType T) const197 std::string Sema::getFixItZeroInitializerForType(QualType T) const {
198 if (T->isScalarType()) {
199 std::string s = getScalarZeroExpressionForType(*T, *this);
200 if (!s.empty())
201 s = " = " + s;
202 return s;
203 }
204
205 const CXXRecordDecl *RD = T->getAsCXXRecordDecl();
206 if (!RD || !RD->hasDefinition())
207 return std::string();
208 if (LangOpts.CPlusPlus0x && !RD->hasUserProvidedDefaultConstructor())
209 return "{}";
210 if (RD->isAggregate())
211 return " = {}";
212 return std::string();
213 }
214
getFixItZeroLiteralForType(QualType T) const215 std::string Sema::getFixItZeroLiteralForType(QualType T) const {
216 return getScalarZeroExpressionForType(*T, *this);
217 }
218