compilerplugins/clang/useuniqueptr.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  */
   9
  10 #include <memory>
  11 #include <cassert>
  12 #include <string>
  13 #include <iostream>
  14 #include <fstream>
  15 #include <set>
  16 #include "plugin.hxx"
  17 #include "check.hxx"
  18
  19 /**
  20   Find destructors that only contain a single call to delete of a field. In which
  21   case that field should really be managed by unique_ptr.
  22 */
  23
  24 namespace {
  25
  26 class UseUniquePtr:
  27     public RecursiveASTVisitor<UseUniquePtr>, public loplugin::Plugin
  28 {
  29 public:
  30     explicit UseUniquePtr(loplugin::InstantiationData const & data):
  31         Plugin(data) {}
  32
  33     virtual void run() override
  34     {
  35         std::string fn(compiler.getSourceManager()
  36                            .getFileEntryForID(compiler.getSourceManager().getMainFileID())
  37                            ->getName());
  38         loplugin::normalizeDotDotInFilePath(fn);
  39         // can't change these because we pass them down to the SfxItemPool stuff
  40         if (fn == SRCDIR "/sc/source/core/data/docpool.cxx")
  41             return;
  42         // this just too clever for me
  43         if (fn == SRCDIR "/sc/source/core/tool/chgtrack.cxx")
  44             return;
  45         // too clever
  46         if (fn == SRCDIR "/pyuno/source/module/pyuno_runtime.cxx")
  47             return;
  48         // m_pExampleSet here is very badly managed. sometimes it is owning, sometimes not,
  49         // and the logic depends on overriding methods.
  50         if (fn == SRCDIR "/sfx2/source/dialog/tabdlg.cxx")
  51             return;
  52         // pLongArr is being deleted here because we temporarily overwrite a pointer to someone else's buffer, with a pointer
  53         // to our own buffer
  54         if (fn == SRCDIR "/editeng/source/misc/txtrange.cxx")
  55             return;
  56         // can't use std::set<std::unique_ptr<>> until C++14
  57         if (fn == SRCDIR "/editeng/source/misc/svxacorr.cxx")
  58             return;
  59
  60         TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
  61     }
  62
  63     bool VisitCXXMethodDecl(const CXXMethodDecl* );
  64     bool VisitCompoundStmt(const CompoundStmt* );
  65 private:
  66     void CheckCompoundStmt(const CXXMethodDecl*, const CompoundStmt* );
  67     void CheckForUnconditionalDelete(const CXXMethodDecl*, const CompoundStmt* );
  68     void CheckForSimpleDelete(const CXXMethodDecl*, const CompoundStmt* );
  69     void CheckRangedLoopDelete(const CXXMethodDecl*, const CXXForRangeStmt* );
  70     void CheckLoopDelete(const CXXMethodDecl*, const Stmt* );
  71     void CheckLoopDelete(const CXXMethodDecl*, const CXXDeleteExpr* );
  72     void CheckDeleteExpr(const CXXMethodDecl*, const CXXDeleteExpr*);
  73     void CheckParenExpr(const CXXMethodDecl*, const ParenExpr*);
  74     void CheckDeleteExpr(const CXXMethodDecl*, const CXXDeleteExpr*,
  75         const MemberExpr*, StringRef message);
  76 };
  77
  78 bool UseUniquePtr::VisitCXXMethodDecl(const CXXMethodDecl* methodDecl)
  79 {
  80     if (ignoreLocation(methodDecl))
  81         return true;
  82     if (isInUnoIncludeFile(methodDecl))
  83         return true;
  84
  85     const CompoundStmt* compoundStmt = dyn_cast_or_null< CompoundStmt >( methodDecl->getBody() );
  86     if (!compoundStmt || compoundStmt->size() == 0)
  87         return true;
  88
  89     CheckCompoundStmt(methodDecl, compoundStmt);
  90
  91     return true;
  92 }
  93
  94 void UseUniquePtr::CheckCompoundStmt(const CXXMethodDecl* methodDecl, const CompoundStmt* compoundStmt)
  95 {
  96     CheckForSimpleDelete(methodDecl, compoundStmt);
  97
  98     for (auto i = compoundStmt->body_begin(); i != compoundStmt->body_end(); ++i)
  99     {
 100         if (auto cxxForRangeStmt = dyn_cast<CXXForRangeStmt>(*i))
 101             CheckRangedLoopDelete(methodDecl, cxxForRangeStmt);
 102         else if (auto forStmt = dyn_cast<ForStmt>(*i))
 103             CheckLoopDelete(methodDecl, forStmt->getBody());
 104         else if (auto whileStmt = dyn_cast<WhileStmt>(*i))
 105             CheckLoopDelete(methodDecl, whileStmt->getBody());
 106         // check for unconditional inner compound statements
 107         else if (auto innerCompoundStmt = dyn_cast<CompoundStmt>(*i))
 108             CheckCompoundStmt(methodDecl, innerCompoundStmt);
 109     }
 110 }
 111
 112 /**
 113  * check for simple call to delete in a destructor i.e. direct unconditional call, or if-guarded call
 114  */
 115 void UseUniquePtr::CheckForSimpleDelete(const CXXMethodDecl* methodDecl, const CompoundStmt* compoundStmt)
 116 {
 117     for (auto i = compoundStmt->body_begin(); i != compoundStmt->body_end(); ++i)
 118     {
 119         auto deleteExpr = dyn_cast<CXXDeleteExpr>(*i);
 120         if (deleteExpr)
 121         {
 122             CheckDeleteExpr(methodDecl, deleteExpr);
 123             continue;
 124         }
 125         auto parenExpr = dyn_cast<ParenExpr>(*i);
 126         if (parenExpr)
 127         {
 128             CheckParenExpr(methodDecl, parenExpr);
 129             continue;
 130         }
 131         // Check for conditional deletes like:
 132         //     if (m_pField != nullptr) delete m_pField;
 133         auto ifStmt = dyn_cast<IfStmt>(*i);
 134         if (!ifStmt)
 135             continue;
 136         auto cond = ifStmt->getCond()->IgnoreImpCasts();
 137         if (auto ifCondMemberExpr = dyn_cast<MemberExpr>(cond))
 138         {
 139             // ignore "if (bMine)"
 140             if (!loplugin::TypeCheck(ifCondMemberExpr->getType()).Pointer())
 141                 continue;
 142             // good
 143         }
 144         else if (auto binaryOp = dyn_cast<BinaryOperator>(cond))
 145         {
 146             if (!isa<MemberExpr>(binaryOp->getLHS()->IgnoreImpCasts()))
 147                 continue;
 148             if (!isa<CXXNullPtrLiteralExpr>(binaryOp->getRHS()->IgnoreImpCasts()))
 149                 continue;
 150             // good
 151         }
 152         else // ignore anything more complicated
 153             continue;
 154
 155         deleteExpr = dyn_cast<CXXDeleteExpr>(ifStmt->getThen());
 156         if (deleteExpr)
 157         {
 158             CheckDeleteExpr(methodDecl, deleteExpr);
 159             continue;
 160         }
 161
 162         parenExpr = dyn_cast<ParenExpr>(ifStmt->getThen());
 163         if (parenExpr)
 164         {
 165             CheckParenExpr(methodDecl, parenExpr);
 166             continue;
 167         }
 168
 169         auto ifThenCompoundStmt = dyn_cast<CompoundStmt>(ifStmt->getThen());
 170         if (!ifThenCompoundStmt)
 171             continue;
 172         for (auto j = ifThenCompoundStmt->body_begin(); j != ifThenCompoundStmt->body_end(); ++j)
 173         {
 174             auto ifDeleteExpr = dyn_cast<CXXDeleteExpr>(*j);
 175             if (ifDeleteExpr)
 176                 CheckDeleteExpr(methodDecl, ifDeleteExpr);
 177             ParenExpr const * parenExpr = dyn_cast<ParenExpr>(*i);
 178             if (parenExpr)
 179                 CheckParenExpr(methodDecl, parenExpr);
 180         }
 181     }
 182 }
 183
 184 /**
 185  * Check the delete expression in a destructor.
 186  */
 187 void UseUniquePtr::CheckDeleteExpr(const CXXMethodDecl* methodDecl, const CXXDeleteExpr* deleteExpr)
 188 {
 189     const ImplicitCastExpr* castExpr = dyn_cast<ImplicitCastExpr>(deleteExpr->getArgument());
 190     if (!castExpr)
 191         return;
 192     const MemberExpr* memberExpr = dyn_cast<MemberExpr>(castExpr->getSubExpr());
 193     if (!memberExpr)
 194         return;
 195     CheckDeleteExpr(methodDecl, deleteExpr, memberExpr,
 196         "unconditional call to delete on a member, should be using std::unique_ptr");
 197 }
 198
 199 /**
 200  * Look for DELETEZ expressions.
 201  */
 202 void UseUniquePtr::CheckParenExpr(const CXXMethodDecl* methodDecl, const ParenExpr* parenExpr)
 203 {
 204     auto binaryOp = dyn_cast<BinaryOperator>(parenExpr->getSubExpr());
 205     if (!binaryOp || binaryOp->getOpcode() != BO_Comma)
 206         return;
 207     auto deleteExpr = dyn_cast<CXXDeleteExpr>(binaryOp->getLHS());
 208     if (!deleteExpr)
 209         return;
 210     CheckDeleteExpr(methodDecl, deleteExpr);
 211 }
 212
 213 /**
 214  * Check the delete expression in a destructor.
 215  */
 216 void UseUniquePtr::CheckDeleteExpr(const CXXMethodDecl* methodDecl, const CXXDeleteExpr* deleteExpr,
 217     const MemberExpr* memberExpr, StringRef message)
 218 {
 219     // ignore union games
 220     const FieldDecl* fieldDecl = dyn_cast<FieldDecl>(memberExpr->getMemberDecl());
 221     if (!fieldDecl)
 222         return;
 223     TagDecl const * td = dyn_cast<TagDecl>(fieldDecl->getDeclContext());
 224     if (td->isUnion())
 225         return;
 226
 227     // ignore calling delete on someone else's field
 228     if (fieldDecl->getParent() != methodDecl->getParent() )
 229         return;
 230
 231     if (ignoreLocation(fieldDecl))
 232         return;
 233     // to ignore things like the CPPUNIT macros
 234     StringRef aFileName = compiler.getSourceManager().getFilename(compiler.getSourceManager().getSpellingLoc(fieldDecl->getLocStart()));
 235     if (loplugin::hasPathnamePrefix(aFileName, WORKDIR "/"))
 236         return;
 237     // passes and stores pointers to member fields
 238     if (loplugin::isSamePathname(aFileName, SRCDIR "/sot/source/sdstor/stgdir.hxx"))
 239         return;
 240     // something platform-specific
 241     if (loplugin::isSamePathname(aFileName, SRCDIR "/hwpfilter/source/htags.h"))
 242         return;
 243     // passes pointers to member fields
 244     if (loplugin::isSamePathname(aFileName, SRCDIR "/sd/inc/sdpptwrp.hxx"))
 245         return;
 246     // @TODO intrusive linked-lists here, with some trickiness
 247     if (loplugin::isSamePathname(aFileName, SRCDIR "/sw/source/filter/html/parcss1.hxx"))
 248         return;
 249     // @TODO SwDoc has some weird ref-counting going on
 250     if (loplugin::isSamePathname(aFileName, SRCDIR "/sw/inc/shellio.hxx"))
 251         return;
 252     // @TODO it's sharing pointers with another class
 253     if (loplugin::isSamePathname(aFileName, SRCDIR "/sc/inc/formulacell.hxx"))
 254         return;
 255     // some weird stuff going on here around struct Entity
 256     if (loplugin::hasPathnamePrefix(aFileName, SRCDIR "/sax/"))
 257         return;
 258     if (loplugin::hasPathnamePrefix(aFileName, SRCDIR "/include/sax/"))
 259         return;
 260     // manipulation of tree structures ie. StgAvlNode, don't lend themselves to std::unique_ptr
 261     if (loplugin::hasPathnamePrefix(aFileName, SRCDIR "/sot/"))
 262         return;
 263     if (loplugin::hasPathnamePrefix(aFileName, SRCDIR "/include/sot/"))
 264         return;
 265     // the std::vector is being passed to another class
 266     if (loplugin::isSamePathname(aFileName, SRCDIR "/sfx2/source/explorer/nochaos.cxx"))
 267         return;
 268     // ignore std::map and std::unordered_map, MSVC 2015 has problems with mixing these with std::unique_ptr
 269     auto tc = loplugin::TypeCheck(fieldDecl->getType());
 270     if (tc.Class("map").StdNamespace() || tc.Class("unordered_map").StdNamespace())
 271         return;
 272     // there is a loop in ~ImplPrnQueueList deleting stuff on a global data structure
 273     if (loplugin::isSamePathname(aFileName, SRCDIR "/vcl/inc/print.h"))
 274         return;
 275     // painful linked list
 276     if (loplugin::isSamePathname(aFileName, SRCDIR "/basic/source/inc/runtime.hxx"))
 277         return;
 278     // not sure how the node management is working here
 279     if (loplugin::isSamePathname(aFileName, SRCDIR "/i18npool/source/localedata/saxparser.cxx"))
 280         return;
 281     // has a pointer that it only sometimes owns
 282     if (loplugin::isSamePathname(aFileName, SRCDIR "/editeng/source/editeng/impedit.hxx"))
 283         return;
 284
 285     report(
 286         DiagnosticsEngine::Warning,
 287         message,
 288         deleteExpr->getLocStart())
 289         << deleteExpr->getSourceRange();
 290     report(
 291         DiagnosticsEngine::Note,
 292         "member is here",
 293         fieldDecl->getLocStart())
 294         << fieldDecl->getSourceRange();
 295 }
 296
 297 void UseUniquePtr::CheckLoopDelete(const CXXMethodDecl* methodDecl, const Stmt* bodyStmt)
 298 {
 299     if (auto deleteExpr = dyn_cast<CXXDeleteExpr>(bodyStmt))
 300         CheckLoopDelete(methodDecl, deleteExpr);
 301     else if (auto compoundStmt = dyn_cast<CompoundStmt>(bodyStmt))
 302     {
 303         for (auto i = compoundStmt->body_begin(); i != compoundStmt->body_end(); ++i)
 304         {
 305             if (auto deleteExpr = dyn_cast<CXXDeleteExpr>(*i))
 306                 CheckLoopDelete(methodDecl, deleteExpr);
 307         }
 308     }
 309 }
 310
 311 void UseUniquePtr::CheckLoopDelete(const CXXMethodDecl* methodDecl, const CXXDeleteExpr* deleteExpr)
 312 {
 313     const MemberExpr* memberExpr = nullptr;
 314     const Expr* subExpr = deleteExpr->getArgument();
 315     for (;;)
 316     {
 317         subExpr = subExpr->IgnoreImpCasts();
 318         if ((memberExpr = dyn_cast<MemberExpr>(subExpr)))
 319             break;
 320         else if (auto arraySubscriptExpr = dyn_cast<ArraySubscriptExpr>(subExpr))
 321             subExpr = arraySubscriptExpr->getBase();
 322         else if (auto cxxOperatorCallExpr = dyn_cast<CXXOperatorCallExpr>(subExpr))
 323         {
 324             if (cxxOperatorCallExpr->getOperator() == OO_Subscript)
 325             {
 326                 memberExpr = dyn_cast<MemberExpr>(cxxOperatorCallExpr->getArg(0));
 327                 break;
 328             }
 329             break;
 330         }
 331         else
 332            break;
 333     }
 334     if (!memberExpr)
 335         return;
 336
 337     CheckDeleteExpr(methodDecl, deleteExpr, memberExpr, "rather manage with std::some_container<std::unique_ptr<T>>");
 338 }
 339
 340 void UseUniquePtr::CheckRangedLoopDelete(const CXXMethodDecl* methodDecl, const CXXForRangeStmt* cxxForRangeStmt)
 341 {
 342     CXXDeleteExpr const * deleteExpr = nullptr;
 343     if (auto compoundStmt = dyn_cast<CompoundStmt>(cxxForRangeStmt->getBody()))
 344         deleteExpr = dyn_cast<CXXDeleteExpr>(*compoundStmt->body_begin());
 345     else
 346         deleteExpr = dyn_cast<CXXDeleteExpr>(cxxForRangeStmt->getBody());
 347     if (!deleteExpr)
 348         return;
 349     auto memberExpr = dyn_cast<MemberExpr>(cxxForRangeStmt->getRangeInit());
 350     if (!memberExpr)
 351         return;
 352     auto fieldDecl = dyn_cast<FieldDecl>(memberExpr->getMemberDecl());
 353     if (!fieldDecl)
 354         return;
 355
 356     CheckDeleteExpr(methodDecl, deleteExpr, memberExpr, "rather manage with std::some_container<std::unique_ptr<T>>");
 357 }
 358
 359 bool UseUniquePtr::VisitCompoundStmt(const CompoundStmt* compoundStmt)
 360 {
 361     if (ignoreLocation(compoundStmt))
 362         return true;
 363     if (isInUnoIncludeFile(compoundStmt->getLocStart()))
 364         return true;
 365     if (compoundStmt->size() == 0) {
 366         return true;
 367     }
 368
 369     auto lastStmt = compoundStmt->body_back();
 370     if (compoundStmt->size() > 1) {
 371         if (isa<ReturnStmt>(lastStmt))
 372             lastStmt = *(++compoundStmt->body_rbegin());
 373     }
 374     auto deleteExpr = dyn_cast<CXXDeleteExpr>(lastStmt);
 375     if (deleteExpr == nullptr) {
 376         return true;
 377     }
 378
 379     auto pCastExpr = dyn_cast<ImplicitCastExpr>(deleteExpr->getArgument());
 380     if (!pCastExpr)
 381         return true;
 382     auto declRefExpr = dyn_cast<DeclRefExpr>(pCastExpr->getSubExpr());
 383     if (!declRefExpr)
 384         return true;
 385     auto varDecl = dyn_cast<VarDecl>(declRefExpr->getDecl());
 386     if (!varDecl)
 387         return true;
 388     if (!varDecl->hasInit()
 389         || !isa<CXXNewExpr>(
 390             varDecl->getInit()->IgnoreImplicit()->IgnoreParenImpCasts()))
 391         return true;
 392     // determine if the var is declared inside the same block as the delete.
 393     // @TODO there should surely be a better way to do this
 394     if (varDecl->getLocStart() < compoundStmt->getLocStart())
 395         return true;
 396
 397     report(
 398         DiagnosticsEngine::Warning,
 399         "deleting a local variable at the end of a block, is a sure sign it should be using std::unique_ptr for that var",
 400         deleteExpr->getLocStart())
 401         << deleteExpr->getSourceRange();
 402     report(
 403         DiagnosticsEngine::Note,
 404         "var is here",
 405         varDecl->getLocStart())
 406         << varDecl->getSourceRange();
 407     return true;
 408 }
 409
 410 loplugin::Plugin::Registration< UseUniquePtr > X("useuniqueptr", false);
 411
 412 }
 413
 414 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */