1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
//===--- Extract.cpp - Clang refactoring library --------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// Implements the "extract" refactoring that can pull code into
/// new functions, methods or declare new variables.
///
//===----------------------------------------------------------------------===//
#include "clang/Tooling/Refactoring/Extract/Extract.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprObjC.h"
#include "clang/Rewrite/Core/Rewriter.h"
#include "clang/Tooling/Refactoring/Extract/SourceExtraction.h"
#include <optional>
namespace clang {
namespace tooling {
namespace {
/// Returns true if \c E is a simple literal or a reference expression that
/// should not be extracted.
bool isSimpleExpression(const Expr *E) {
if (!E)
return false;
switch (E->IgnoreParenCasts()->getStmtClass()) {
case Stmt::DeclRefExprClass:
case Stmt::PredefinedExprClass:
case Stmt::IntegerLiteralClass:
case Stmt::FloatingLiteralClass:
case Stmt::ImaginaryLiteralClass:
case Stmt::CharacterLiteralClass:
case Stmt::StringLiteralClass:
return true;
default:
return false;
}
}
SourceLocation computeFunctionExtractionLocation(const Decl *D) {
if (isa<CXXMethodDecl>(D)) {
// Code from method that is defined in class body should be extracted to a
// function defined just before the class.
while (const auto *RD = dyn_cast<CXXRecordDecl>(D->getLexicalDeclContext()))
D = RD;
}
return D->getBeginLoc();
}
} // end anonymous namespace
const RefactoringDescriptor &ExtractFunction::describe() {
static const RefactoringDescriptor Descriptor = {
"extract-function",
"Extract Function",
"(WIP action; use with caution!) Extracts code into a new function",
};
return Descriptor;
}
Expected<ExtractFunction>
ExtractFunction::initiate(RefactoringRuleContext &Context,
CodeRangeASTSelection Code,
std::optional<std::string> DeclName) {
// We would like to extract code out of functions/methods/blocks.
// Prohibit extraction from things like global variable / field
// initializers and other top-level expressions.
if (!Code.isInFunctionLikeBodyOfCode())
return Context.createDiagnosticError(
diag::err_refactor_code_outside_of_function);
if (Code.size() == 1) {
// Avoid extraction of simple literals and references.
if (isSimpleExpression(dyn_cast<Expr>(Code[0])))
return Context.createDiagnosticError(
diag::err_refactor_extract_simple_expression);
// Property setters can't be extracted.
if (const auto *PRE = dyn_cast<ObjCPropertyRefExpr>(Code[0])) {
if (!PRE->isMessagingGetter())
return Context.createDiagnosticError(
diag::err_refactor_extract_prohibited_expression);
}
}
return ExtractFunction(std::move(Code), DeclName);
}
// FIXME: Support C++ method extraction.
// FIXME: Support Objective-C method extraction.
Expected<AtomicChanges>
ExtractFunction::createSourceReplacements(RefactoringRuleContext &Context) {
const Decl *ParentDecl = Code.getFunctionLikeNearestParent();
assert(ParentDecl && "missing parent");
// Compute the source range of the code that should be extracted.
SourceRange ExtractedRange(Code[0]->getBeginLoc(),
Code[Code.size() - 1]->getEndLoc());
// FIXME (Alex L): Add code that accounts for macro locations.
ASTContext &AST = Context.getASTContext();
SourceManager &SM = AST.getSourceManager();
const LangOptions &LangOpts = AST.getLangOpts();
Rewriter ExtractedCodeRewriter(SM, LangOpts);
// FIXME: Capture used variables.
// Compute the return type.
QualType ReturnType = AST.VoidTy;
// FIXME (Alex L): Account for the return statement in extracted code.
// FIXME (Alex L): Check for lexical expression instead.
bool IsExpr = Code.size() == 1 && isa<Expr>(Code[0]);
if (IsExpr) {
// FIXME (Alex L): Get a more user-friendly type if needed.
ReturnType = cast<Expr>(Code[0])->getType();
}
// FIXME: Rewrite the extracted code performing any required adjustments.
// FIXME: Capture any field if necessary (method -> function extraction).
// FIXME: Sort captured variables by name.
// FIXME: Capture 'this' / 'self' if necessary.
// FIXME: Compute the actual parameter types.
// Compute the location of the extracted declaration.
SourceLocation ExtractedDeclLocation =
computeFunctionExtractionLocation(ParentDecl);
// FIXME: Adjust the location to account for any preceding comments.
// FIXME: Adjust with PP awareness like in Sema to get correct 'bool'
// treatment.
PrintingPolicy PP = AST.getPrintingPolicy();
// FIXME: PP.UseStdFunctionForLambda = true;
PP.SuppressStrongLifetime = true;
PP.SuppressLifetimeQualifiers = true;
PP.SuppressUnwrittenScope = true;
ExtractionSemicolonPolicy Semicolons = ExtractionSemicolonPolicy::compute(
Code[Code.size() - 1], ExtractedRange, SM, LangOpts);
AtomicChange Change(SM, ExtractedDeclLocation);
// Create the replacement for the extracted declaration.
{
std::string ExtractedCode;
llvm::raw_string_ostream OS(ExtractedCode);
// FIXME: Use 'inline' in header.
OS << "static ";
ReturnType.print(OS, PP, DeclName);
OS << '(';
// FIXME: Arguments.
OS << ')';
// Function body.
OS << " {\n";
if (IsExpr && !ReturnType->isVoidType())
OS << "return ";
OS << ExtractedCodeRewriter.getRewrittenText(ExtractedRange);
if (Semicolons.isNeededInExtractedFunction())
OS << ';';
OS << "\n}\n\n";
auto Err = Change.insert(SM, ExtractedDeclLocation, OS.str());
if (Err)
return std::move(Err);
}
// Create the replacement for the call to the extracted declaration.
{
std::string ReplacedCode;
llvm::raw_string_ostream OS(ReplacedCode);
OS << DeclName << '(';
// FIXME: Forward arguments.
OS << ')';
if (Semicolons.isNeededInOriginalFunction())
OS << ';';
auto Err = Change.replace(
SM, CharSourceRange::getTokenRange(ExtractedRange), OS.str());
if (Err)
return std::move(Err);
}
// FIXME: Add support for assocciated symbol location to AtomicChange to mark
// the ranges of the name of the extracted declaration.
return AtomicChanges{std::move(Change)};
}
} // end namespace tooling
} // end namespace clang
|
