1//===--- TransUnusedInitDelegate.cpp - Transformations to ARC mode --------===//
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// Transformations:
9//===----------------------------------------------------------------------===//
10//
11// rewriteUnusedInitDelegate:
12//
13// Rewrites an unused result of calling a delegate initialization, to assigning
14// the result to self.
15// e.g
16// [self init];
17// ---->
18// self = [self init];
19//
20//===----------------------------------------------------------------------===//
21
22#include "Transforms.h"
23#include "Internals.h"
24#include "clang/AST/ASTContext.h"
25#include "clang/Sema/SemaDiagnostic.h"
26
27using namespace clang;
28using namespace arcmt;
29using namespace trans;
30
31namespace {
32
33class UnusedInitRewriter : public RecursiveASTVisitor<UnusedInitRewriter> {
34 Stmt *Body;
35 MigrationPass &Pass;
36
37 ExprSet Removables;
38
39public:
40 UnusedInitRewriter(MigrationPass &pass)
41 : Body(nullptr), Pass(pass) { }
42
43 void transformBody(Stmt *body, Decl *ParentD) {
44 Body = body;
45 collectRemovables(S: body, exprs&: Removables);
46 TraverseStmt(S: body);
47 }
48
49 bool VisitObjCMessageExpr(ObjCMessageExpr *ME) {
50 if (ME->isDelegateInitCall() &&
51 isRemovable(E: ME) &&
52 Pass.TA.hasDiagnostic(ID: diag::err_arc_unused_init_message,
53 range: ME->getExprLoc())) {
54 Transaction Trans(Pass.TA);
55 Pass.TA.clearDiagnostic(IDs: diag::err_arc_unused_init_message,
56 range: ME->getExprLoc());
57 SourceRange ExprRange = ME->getSourceRange();
58 Pass.TA.insert(loc: ExprRange.getBegin(), text: "if (!(self = ");
59 std::string retStr = ")) return ";
60 retStr += getNilString(Pass);
61 Pass.TA.insertAfterToken(loc: ExprRange.getEnd(), text: retStr);
62 }
63 return true;
64 }
65
66private:
67 bool isRemovable(Expr *E) const {
68 return Removables.count(V: E);
69 }
70};
71
72} // anonymous namespace
73
74void trans::rewriteUnusedInitDelegate(MigrationPass &pass) {
75 BodyTransform<UnusedInitRewriter> trans(pass);
76 trans.TraverseDecl(D: pass.Ctx.getTranslationUnitDecl());
77}
78