llvm-project/clang/lib/ARCMigrate/TransUnusedInitDelegate.cpp

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2012-11-14 23:08:31 +08:00
//===--- TransUnusedInitDelegate.cpp - Transformations to ARC mode --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// Transformations:
//===----------------------------------------------------------------------===//
//
// rewriteUnusedInitDelegate:
//
// Rewrites an unused result of calling a delegate initialization, to assigning
// the result to self.
// e.g
// [self init];
// ---->
// self = [self init];
//
//===----------------------------------------------------------------------===//
#include "Transforms.h"
#include "Internals.h"
#include "clang/AST/ASTContext.h"
#include "clang/Sema/SemaDiagnostic.h"
using namespace clang;
using namespace arcmt;
using namespace trans;
namespace {
class UnusedInitRewriter : public RecursiveASTVisitor<UnusedInitRewriter> {
Stmt *Body;
MigrationPass &Pass;
ExprSet Removables;
public:
UnusedInitRewriter(MigrationPass &pass)
: Body(nullptr), Pass(pass) { }
void transformBody(Stmt *body, Decl *ParentD) {
Body = body;
collectRemovables(body, Removables);
TraverseStmt(body);
}
bool VisitObjCMessageExpr(ObjCMessageExpr *ME) {
if (ME->isDelegateInitCall() &&
isRemovable(ME) &&
Pass.TA.hasDiagnostic(diag::err_arc_unused_init_message,
ME->getExprLoc())) {
Transaction Trans(Pass.TA);
Pass.TA.clearDiagnostic(diag::err_arc_unused_init_message,
ME->getExprLoc());
SourceRange ExprRange = ME->getSourceRange();
Pass.TA.insert(ExprRange.getBegin(), "if (!(self = ");
std::string retStr = ")) return ";
retStr += getNilString(Pass.Ctx);
Pass.TA.insertAfterToken(ExprRange.getEnd(), retStr);
}
return true;
}
private:
bool isRemovable(Expr *E) const {
return Removables.count(E);
}
};
} // anonymous namespace
void trans::rewriteUnusedInitDelegate(MigrationPass &pass) {
BodyTransform<UnusedInitRewriter> trans(pass);
trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
}