1 //===--- SourceCodeBuilder.cpp ----------------------------------*- 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 #include "clang/Tooling/Transformer/SourceCodeBuilders.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/AST/Expr.h"
12 #include "clang/AST/ExprCXX.h"
13 #include "clang/Tooling/Transformer/SourceCode.h"
14 #include "llvm/ADT/Twine.h"
15 #include <string>
16
17 using namespace clang;
18 using namespace tooling;
19
reallyIgnoreImplicit(const Expr & E)20 const Expr *tooling::reallyIgnoreImplicit(const Expr &E) {
21 const Expr *Expr = E.IgnoreImplicit();
22 if (const auto *CE = dyn_cast<CXXConstructExpr>(Expr)) {
23 if (CE->getNumArgs() > 0 &&
24 CE->getArg(0)->getSourceRange() == Expr->getSourceRange())
25 return CE->getArg(0)->IgnoreImplicit();
26 }
27 return Expr;
28 }
29
mayEverNeedParens(const Expr & E)30 bool tooling::mayEverNeedParens(const Expr &E) {
31 const Expr *Expr = reallyIgnoreImplicit(E);
32 // We always want parens around unary, binary, and ternary operators, because
33 // they are lower precedence.
34 if (isa<UnaryOperator>(Expr) || isa<BinaryOperator>(Expr) ||
35 isa<AbstractConditionalOperator>(Expr))
36 return true;
37
38 // We need parens around calls to all overloaded operators except: function
39 // calls, subscripts, and expressions that are already part of an (implicit)
40 // call to operator->. These latter are all in the same precedence level as
41 // dot/arrow and that level is left associative, so they don't need parens
42 // when appearing on the left.
43 if (const auto *Op = dyn_cast<CXXOperatorCallExpr>(Expr))
44 return Op->getOperator() != OO_Call && Op->getOperator() != OO_Subscript &&
45 Op->getOperator() != OO_Arrow;
46
47 return false;
48 }
49
needParensAfterUnaryOperator(const Expr & E)50 bool tooling::needParensAfterUnaryOperator(const Expr &E) {
51 const Expr *Expr = reallyIgnoreImplicit(E);
52 if (isa<BinaryOperator>(Expr) || isa<AbstractConditionalOperator>(Expr))
53 return true;
54
55 if (const auto *Op = dyn_cast<CXXOperatorCallExpr>(Expr))
56 return Op->getNumArgs() == 2 && Op->getOperator() != OO_PlusPlus &&
57 Op->getOperator() != OO_MinusMinus && Op->getOperator() != OO_Call &&
58 Op->getOperator() != OO_Subscript;
59
60 return false;
61 }
62
buildParens(const Expr & E,const ASTContext & Context)63 llvm::Optional<std::string> tooling::buildParens(const Expr &E,
64 const ASTContext &Context) {
65 StringRef Text = getText(E, Context);
66 if (Text.empty())
67 return llvm::None;
68 if (mayEverNeedParens(E))
69 return ("(" + Text + ")").str();
70 return Text.str();
71 }
72
73 llvm::Optional<std::string>
buildDereference(const Expr & E,const ASTContext & Context)74 tooling::buildDereference(const Expr &E, const ASTContext &Context) {
75 if (const auto *Op = dyn_cast<UnaryOperator>(&E))
76 if (Op->getOpcode() == UO_AddrOf) {
77 // Strip leading '&'.
78 StringRef Text =
79 getText(*Op->getSubExpr()->IgnoreParenImpCasts(), Context);
80 if (Text.empty())
81 return llvm::None;
82 return Text.str();
83 }
84
85 StringRef Text = getText(E, Context);
86 if (Text.empty())
87 return llvm::None;
88 // Add leading '*'.
89 if (needParensAfterUnaryOperator(E))
90 return ("*(" + Text + ")").str();
91 return ("*" + Text).str();
92 }
93
buildAddressOf(const Expr & E,const ASTContext & Context)94 llvm::Optional<std::string> tooling::buildAddressOf(const Expr &E,
95 const ASTContext &Context) {
96 if (const auto *Op = dyn_cast<UnaryOperator>(&E))
97 if (Op->getOpcode() == UO_Deref) {
98 // Strip leading '*'.
99 StringRef Text =
100 getText(*Op->getSubExpr()->IgnoreParenImpCasts(), Context);
101 if (Text.empty())
102 return llvm::None;
103 return Text.str();
104 }
105 // Add leading '&'.
106 StringRef Text = getText(E, Context);
107 if (Text.empty())
108 return llvm::None;
109 if (needParensAfterUnaryOperator(E)) {
110 return ("&(" + Text + ")").str();
111 }
112 return ("&" + Text).str();
113 }
114
buildDot(const Expr & E,const ASTContext & Context)115 llvm::Optional<std::string> tooling::buildDot(const Expr &E,
116 const ASTContext &Context) {
117 if (const auto *Op = llvm::dyn_cast<UnaryOperator>(&E))
118 if (Op->getOpcode() == UO_Deref) {
119 // Strip leading '*', add following '->'.
120 const Expr *SubExpr = Op->getSubExpr()->IgnoreParenImpCasts();
121 StringRef DerefText = getText(*SubExpr, Context);
122 if (DerefText.empty())
123 return llvm::None;
124 if (needParensBeforeDotOrArrow(*SubExpr))
125 return ("(" + DerefText + ")->").str();
126 return (DerefText + "->").str();
127 }
128
129 // Add following '.'.
130 StringRef Text = getText(E, Context);
131 if (Text.empty())
132 return llvm::None;
133 if (needParensBeforeDotOrArrow(E)) {
134 return ("(" + Text + ").").str();
135 }
136 return (Text + ".").str();
137 }
138
buildArrow(const Expr & E,const ASTContext & Context)139 llvm::Optional<std::string> tooling::buildArrow(const Expr &E,
140 const ASTContext &Context) {
141 if (const auto *Op = llvm::dyn_cast<UnaryOperator>(&E))
142 if (Op->getOpcode() == UO_AddrOf) {
143 // Strip leading '&', add following '.'.
144 const Expr *SubExpr = Op->getSubExpr()->IgnoreParenImpCasts();
145 StringRef DerefText = getText(*SubExpr, Context);
146 if (DerefText.empty())
147 return llvm::None;
148 if (needParensBeforeDotOrArrow(*SubExpr))
149 return ("(" + DerefText + ").").str();
150 return (DerefText + ".").str();
151 }
152
153 // Add following '->'.
154 StringRef Text = getText(E, Context);
155 if (Text.empty())
156 return llvm::None;
157 if (needParensBeforeDotOrArrow(E))
158 return ("(" + Text + ")->").str();
159 return (Text + "->").str();
160 }
161