1//===--- SemaFixItUtils.cpp - Sema FixIts ---------------------------------===//
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 helper classes for generation of Sema FixItHints.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/AST/ASTContext.h"
14#include "clang/AST/ExprCXX.h"
15#include "clang/AST/ExprObjC.h"
16#include "clang/Lex/Preprocessor.h"
17#include "clang/Sema/Sema.h"
18#include "clang/Sema/SemaFixItUtils.h"
19
20using namespace clang;
21
22bool ConversionFixItGenerator::compareTypesSimple(CanQualType From,
23 CanQualType To,
24 Sema &S,
25 SourceLocation Loc,
26 ExprValueKind FromVK) {
27 if (!To.isAtLeastAsQualifiedAs(Other: From, Ctx: S.getASTContext()))
28 return false;
29
30 From = From.getNonReferenceType();
31 To = To.getNonReferenceType();
32
33 // If both are pointer types, work with the pointee types.
34 if (isa<PointerType>(Val: From) && isa<PointerType>(Val: To)) {
35 From = S.Context.getCanonicalType(
36 T: (cast<PointerType>(Val&: From))->getPointeeType());
37 To = S.Context.getCanonicalType(
38 T: (cast<PointerType>(Val&: To))->getPointeeType());
39 }
40
41 const CanQualType FromUnq = From.getUnqualifiedType();
42 const CanQualType ToUnq = To.getUnqualifiedType();
43
44 if ((FromUnq == ToUnq || (S.IsDerivedFrom(Loc, Derived: FromUnq, Base: ToUnq))) &&
45 To.isAtLeastAsQualifiedAs(Other: From, Ctx: S.getASTContext()))
46 return true;
47 return false;
48}
49
50bool ConversionFixItGenerator::tryToFixConversion(const Expr *FullExpr,
51 const QualType FromTy,
52 const QualType ToTy,
53 Sema &S) {
54 if (!FullExpr)
55 return false;
56
57 const CanQualType FromQTy = S.Context.getCanonicalType(T: FromTy);
58 const CanQualType ToQTy = S.Context.getCanonicalType(T: ToTy);
59 const SourceLocation Begin = FullExpr->getSourceRange().getBegin();
60 const SourceLocation End = S.getLocForEndOfToken(Loc: FullExpr->getSourceRange()
61 .getEnd());
62
63 // Strip the implicit casts - those are implied by the compiler, not the
64 // original source code.
65 const Expr* Expr = FullExpr->IgnoreImpCasts();
66
67 bool NeedParen = true;
68 if (isa<ArraySubscriptExpr>(Val: Expr) ||
69 isa<CallExpr>(Val: Expr) ||
70 isa<DeclRefExpr>(Val: Expr) ||
71 isa<CastExpr>(Val: Expr) ||
72 isa<CXXNewExpr>(Val: Expr) ||
73 isa<CXXConstructExpr>(Val: Expr) ||
74 isa<CXXDeleteExpr>(Val: Expr) ||
75 isa<CXXNoexceptExpr>(Val: Expr) ||
76 isa<CXXPseudoDestructorExpr>(Val: Expr) ||
77 isa<CXXScalarValueInitExpr>(Val: Expr) ||
78 isa<CXXThisExpr>(Val: Expr) ||
79 isa<CXXTypeidExpr>(Val: Expr) ||
80 isa<CXXUnresolvedConstructExpr>(Val: Expr) ||
81 isa<ObjCMessageExpr>(Val: Expr) ||
82 isa<ObjCPropertyRefExpr>(Val: Expr) ||
83 isa<ObjCProtocolExpr>(Val: Expr) ||
84 isa<MemberExpr>(Val: Expr) ||
85 isa<ParenExpr>(Val: FullExpr) ||
86 isa<ParenListExpr>(Val: Expr) ||
87 isa<SizeOfPackExpr>(Val: Expr) ||
88 isa<UnaryOperator>(Val: Expr))
89 NeedParen = false;
90
91 // Check if the argument needs to be dereferenced:
92 // (type * -> type) or (type * -> type &).
93 if (const PointerType *FromPtrTy = dyn_cast<PointerType>(Val: FromQTy)) {
94 OverloadFixItKind FixKind = OFIK_Dereference;
95
96 bool CanConvert = CompareTypes(
97 S.Context.getCanonicalType(T: FromPtrTy->getPointeeType()), ToQTy,
98 S, Begin, VK_LValue);
99 if (CanConvert) {
100 // Do not suggest dereferencing a Null pointer.
101 if (Expr->IgnoreParenCasts()->
102 isNullPointerConstant(Ctx&: S.Context, NPC: Expr::NPC_ValueDependentIsNotNull))
103 return false;
104
105 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(Val: Expr)) {
106 if (UO->getOpcode() == UO_AddrOf) {
107 FixKind = OFIK_RemoveTakeAddress;
108 Hints.push_back(x: FixItHint::CreateRemoval(
109 RemoveRange: CharSourceRange::getTokenRange(B: Begin, E: Begin)));
110 }
111 } else if (NeedParen) {
112 Hints.push_back(x: FixItHint::CreateInsertion(InsertionLoc: Begin, Code: "*("));
113 Hints.push_back(x: FixItHint::CreateInsertion(InsertionLoc: End, Code: ")"));
114 } else {
115 Hints.push_back(x: FixItHint::CreateInsertion(InsertionLoc: Begin, Code: "*"));
116 }
117
118 NumConversionsFixed++;
119 if (NumConversionsFixed == 1)
120 Kind = FixKind;
121 return true;
122 }
123 }
124
125 // Check if the pointer to the argument needs to be passed:
126 // (type -> type *) or (type & -> type *).
127 if (const auto *ToPtrTy = dyn_cast<PointerType>(Val: ToQTy)) {
128 bool CanConvert = false;
129 OverloadFixItKind FixKind = OFIK_TakeAddress;
130
131 // Only suggest taking address of L-values.
132 if (!Expr->isLValue() || Expr->getObjectKind() != OK_Ordinary)
133 return false;
134
135 // Do no take address of const pointer to get void*
136 if (isa<PointerType>(Val: FromQTy) && ToPtrTy->isVoidPointerType())
137 return false;
138
139 CanConvert = CompareTypes(S.Context.getPointerType(T: FromQTy), ToQTy, S,
140 Begin, VK_PRValue);
141 if (CanConvert) {
142
143 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(Val: Expr)) {
144 if (UO->getOpcode() == UO_Deref) {
145 FixKind = OFIK_RemoveDereference;
146 Hints.push_back(x: FixItHint::CreateRemoval(
147 RemoveRange: CharSourceRange::getTokenRange(B: Begin, E: Begin)));
148 }
149 } else if (NeedParen) {
150 Hints.push_back(x: FixItHint::CreateInsertion(InsertionLoc: Begin, Code: "&("));
151 Hints.push_back(x: FixItHint::CreateInsertion(InsertionLoc: End, Code: ")"));
152 } else {
153 Hints.push_back(x: FixItHint::CreateInsertion(InsertionLoc: Begin, Code: "&"));
154 }
155
156 NumConversionsFixed++;
157 if (NumConversionsFixed == 1)
158 Kind = FixKind;
159 return true;
160 }
161 }
162
163 return false;
164}
165
166static bool isMacroDefined(const Sema &S, SourceLocation Loc, StringRef Name) {
167 return (bool)S.PP.getMacroDefinitionAtLoc(II: &S.getASTContext().Idents.get(Name),
168 Loc);
169}
170
171static std::string getScalarZeroExpressionForType(
172 const Type &T, SourceLocation Loc, const Sema &S) {
173 assert(T.isScalarType() && "use scalar types only");
174 // Suggest "0" for non-enumeration scalar types, unless we can find a
175 // better initializer.
176 if (T.isEnumeralType())
177 return std::string();
178 if ((T.isObjCObjectPointerType() || T.isBlockPointerType()) &&
179 isMacroDefined(S, Loc, Name: "nil"))
180 return "nil";
181 if (T.isRealFloatingType())
182 return "0.0";
183 if (T.isBooleanType() &&
184 (S.LangOpts.CPlusPlus || isMacroDefined(S, Loc, Name: "false")))
185 return "false";
186 if (T.isPointerType() || T.isMemberPointerType()) {
187 if (S.LangOpts.CPlusPlus11)
188 return "nullptr";
189 if (isMacroDefined(S, Loc, Name: "NULL"))
190 return "NULL";
191 }
192 if (T.isCharType())
193 return "'\\0'";
194 if (T.isWideCharType())
195 return "L'\\0'";
196 if (T.isChar16Type())
197 return "u'\\0'";
198 if (T.isChar32Type())
199 return "U'\\0'";
200 return "0";
201}
202
203std::string
204Sema::getFixItZeroInitializerForType(QualType T, SourceLocation Loc) const {
205 if (T->isScalarType()) {
206 std::string s = getScalarZeroExpressionForType(T: *T, Loc, S: *this);
207 if (!s.empty())
208 s = " = " + s;
209 return s;
210 }
211
212 const CXXRecordDecl *RD = T->getAsCXXRecordDecl();
213 if (!RD || !RD->hasDefinition())
214 return std::string();
215 if (LangOpts.CPlusPlus11 && !RD->hasUserProvidedDefaultConstructor())
216 return "{}";
217 if (RD->isAggregate())
218 return " = {}";
219 return std::string();
220}
221
222std::string
223Sema::getFixItZeroLiteralForType(QualType T, SourceLocation Loc) const {
224 return getScalarZeroExpressionForType(T: *T, Loc, S: *this);
225}
226