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
27 using namespace clang;
28 using namespace arcmt;
29 using namespace trans;
30
31 namespace {
32
33 class UnusedInitRewriter : public RecursiveASTVisitor<UnusedInitRewriter> {
34 Stmt *Body;
35 MigrationPass &Pass;
36
37 ExprSet Removables;
38
39 public:
UnusedInitRewriter(MigrationPass & pass)40 UnusedInitRewriter(MigrationPass &pass)
41 : Body(nullptr), Pass(pass) { }
42
transformBody(Stmt * body,Decl * ParentD)43 void transformBody(Stmt *body, Decl *ParentD) {
44 Body = body;
45 collectRemovables(body, Removables);
46 TraverseStmt(body);
47 }
48
VisitObjCMessageExpr(ObjCMessageExpr * ME)49 bool VisitObjCMessageExpr(ObjCMessageExpr *ME) {
50 if (ME->isDelegateInitCall() &&
51 isRemovable(ME) &&
52 Pass.TA.hasDiagnostic(diag::err_arc_unused_init_message,
53 ME->getExprLoc())) {
54 Transaction Trans(Pass.TA);
55 Pass.TA.clearDiagnostic(diag::err_arc_unused_init_message,
56 ME->getExprLoc());
57 SourceRange ExprRange = ME->getSourceRange();
58 Pass.TA.insert(ExprRange.getBegin(), "if (!(self = ");
59 std::string retStr = ")) return ";
60 retStr += getNilString(Pass);
61 Pass.TA.insertAfterToken(ExprRange.getEnd(), retStr);
62 }
63 return true;
64 }
65
66 private:
isRemovable(Expr * E) const67 bool isRemovable(Expr *E) const {
68 return Removables.count(E);
69 }
70 };
71
72 } // anonymous namespace
73
rewriteUnusedInitDelegate(MigrationPass & pass)74 void trans::rewriteUnusedInitDelegate(MigrationPass &pass) {
75 BodyTransform<UnusedInitRewriter> trans(pass);
76 trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
77 }
78