compilerplugins/clang/store/constantfunction.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 "plugin.hxx"
  11 #include <iostream>
  12
  13 /*
  14   Look for member functions that merely return a compile-time constant, or they are empty, and can thus
  15   be either removed, or converted into a constant.
  16
  17   This mostly tends to happen as a side-effect of other cleanups.
  18 */
  19 namespace {
  20
  21 class ConstantFunction:
  22     public loplugin::FilteringPlugin<ConstantFunction>
  23 {
  24     StringRef getFilename(const FunctionDecl* functionDecl);
  25 public:
  26     explicit ConstantFunction(InstantiationData const & data): FilteringRewritePlugin(data) {}
  27
  28     void run() override
  29     {
  30         // these files crash clang-3.5 somewhere in the isEvaluatable/EvaluateAsXXX stuff
  31 /*        FileID mainFileID = compiler.getSourceManager().getMainFileID();
  32         if (strstr(compiler.getSourceManager().getFileEntryForID(mainFileID)->getName(), "bootstrapfixture.cxx") != 0) {
  33             return;
  34         }
  35         if (strstr(compiler.getSourceManager().getFileEntryForID(mainFileID)->getName(), "gtk3gtkinst.cxx") != 0) {
  36             return;
  37         }*/
  38
  39         TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
  40     }
  41
  42     bool VisitFunctionDecl(const FunctionDecl *);
  43 };
  44
  45 StringRef ConstantFunction::getFilename(const FunctionDecl* functionDecl)
  46 {
  47     SourceLocation spellingLocation = compiler.getSourceManager().getSpellingLoc(functionDecl->getCanonicalDecl()->getNameInfo().getLoc());
  48     StringRef name { compiler.getSourceManager().getFilename(spellingLocation) };
  49     return name;
  50 }
  51
  52 static bool startsWith(const std::string& rStr, const char* pSubStr) {
  53     return rStr.compare(0, strlen(pSubStr), pSubStr) == 0;
  54 }
  55
  56 bool ConstantFunction::VisitFunctionDecl(const FunctionDecl * pFunctionDecl) {
  57     if (ignoreLocation(pFunctionDecl)) {
  58         return true;
  59     }
  60     if (!pFunctionDecl->hasBody()) {
  61         return true;
  62     }
  63     if (!pFunctionDecl->isThisDeclarationADefinition()) {
  64         return true;
  65     }
  66     // stuff declared extern-C is almost always used as a some kind of callback
  67     if (pFunctionDecl->isExternC()) {
  68         return true;
  69     }
  70     if (pFunctionDecl->isConstexpr()) {
  71         return true;
  72     }
  73     if (pFunctionDecl->isMain()) {
  74         return true;
  75     }
  76
  77     StringRef aFileName = getFilename(pFunctionDecl);
  78
  79     // various tests in here are empty stubs under Linux
  80     if (aFileName.startswith(SRCDIR "/sal/qa/")) {
  81         return true;
  82     }
  83     // lots of empty stuff here where it looks like someone is still going to "fill in the blanks"
  84     if (aFileName.startswith(SRCDIR "/basegfx/test/")) {
  85         return true;
  86     }
  87     // bridges has some weird stuff in it....
  88     if (aFileName.startswith(SRCDIR "/bridges/")) {
  89         return true;
  90     }
  91     // dummy implementation of DDE, since it is only active on Windows
  92     if (aFileName == SRCDIR "/svl/unx/source/svdde/ddedummy.cxx"
  93         || aFileName == SRCDIR "/include/svl/svdde.hxx") {
  94         return true;
  95     }
  96     // fancy templates at work here
  97     if (aFileName == SRCDIR "/vcl/source/gdi/bmpfast.cxx") {
  98         return true;
  99     }
 100     // bunch of stuff used as callbacks here
 101     if (aFileName == SRCDIR "/vcl/generic/glyphs/gcach_layout.cxx") {
 102         return true;
 103     }
 104     // salplug runtime-loading mechanism at work
 105     if (aFileName == SRCDIR "/vcl/inc/salinst.hxx") {
 106         return true;
 107     }
 108     // lots of callbacks here
 109     if (aFileName == SRCDIR "/extensions/source/plugin/unx/npnapi.cxx") {
 110         return true;
 111     }
 112     // vcl/unx/gtk3 re-using vcl/unx/gtk:
 113     if (aFileName.find("/../../gtk/") != std::string::npos) {
 114         return true;
 115     }
 116     // used by code generated by python
 117     if (aFileName == SRCDIR "/writerfilter/source/ooxml/OOXMLFastContextHandler.hxx") {
 118         return true;
 119     }
 120     // this test just test the include of some headers
 121     if (aFileName == SRCDIR "/officecfg/qa/cppheader.cxx") {
 122         return true;
 123     }
 124     // just ignore this for now, people furiously hacking in there
 125     if (startsWith(aFileName, SRCDIR "/libreofficekit")) {
 126         return true;
 127     }
 128
 129
 130     const CXXMethodDecl *pCXXMethodDecl = dyn_cast<CXXMethodDecl>(pFunctionDecl);
 131     if (pCXXMethodDecl) {
 132         if (pCXXMethodDecl->isVirtual()) {
 133             return true;
 134         }
 135         // static with inline body will be optimised at compile-time to a constant anyway
 136         if (pCXXMethodDecl->isStatic() && (pCXXMethodDecl->hasInlineBody() || pCXXMethodDecl->isInlineSpecified())) {
 137             return true;
 138         }
 139         // this catches some stuff in templates
 140         if (pFunctionDecl->hasAttr<OverrideAttr>()) {
 141             return true;
 142         }
 143     }
 144     // a free function with an inline body will be optimised at compile-time to a constant anyway
 145     if (!pCXXMethodDecl && pFunctionDecl->isInlineSpecified()) {
 146         return true;
 147     }
 148     if (isa<CXXConstructorDecl>(pFunctionDecl) || isa<CXXDestructorDecl>(pFunctionDecl) || isa<CXXConversionDecl>(pFunctionDecl)) {
 149         return true;
 150     }
 151     if (isInUnoIncludeFile(pFunctionDecl)) {
 152         return true;
 153     }
 154
 155     switch (pFunctionDecl->getOverloadedOperator()) {
 156     case OO_Delete:
 157     case OO_EqualEqual:
 158     case OO_Call:
 159         return true;
 160     default:
 161         break;
 162     }
 163
 164     std::string aFunctionName = pFunctionDecl->getQualifiedNameAsString();
 165
 166     // something to do with dynamic loading in sal/textenc/textenc.cxx
 167     if (aFunctionName == "thisModule") {
 168         return true;
 169     }
 170     // an empty stub under certain conditions, sal/osl/unx/thread.cxx
 171     if (aFunctionName == "osl_thread_priority_init_Impl") {
 172         return true;
 173     }
 174     // a pointer to this function is taken and passed to an underlying API, cppu/source/uno/lbenv.cxx
 175     if (aFunctionName == "defenv_dispose") {
 176         return true;
 177     }
 178     // a pointer to this function is taken and passed to an underlying API, cppuhelper/source/exc_thrower.cxx
 179     if (aFunctionName == "ExceptionThrower_acquire_release_nop") {
 180         return true;
 181     }
 182     // used as a callback, /vcl/source/filter/jpeg/JpegReader.cxx
 183     if (aFunctionName == "term_source") {
 184         return true;
 185     }
 186     // only valid for windows, extensions/source/update/check/updatecheck.cxx
 187     if (aFunctionName == "(anonymous namespace)::UpdateCheckThread::hasInternetConnection") {
 188         return true;
 189     }
 190     // used as callback, extensions/source/plugin/unx/npwrap.cxx
 191     if (aFunctionName == "plugin_x_error_handler" || aFunctionName == "noClosure") {
 192         return true;
 193     }
 194     // used as callback, sax/source/expatwrap/sax_expat.cxx
 195     if (aFunctionName == "(anonymous namespace)::SaxExpatParser_Impl::callbackUnknownEncoding") {
 196         return true;
 197     }
 198     // used as callback, i18npool/source/textconversion/textconversion.cxx
 199     if (aFunctionName == "com::sun::star::i18n::nullFunc") {
 200         return true;
 201     }
 202     // used as callback, xmloff/source/text/txtparae.cxx
 203     if (aFunctionName == "(anonymous namespace)::lcl_TextContentsUnfiltered") {
 204         return true;
 205     }
 206     // template magic, include/canvas/verifyinput.hxx
 207     if (aFunctionName == "canvas::tools::verifyInput") {
 208         return true;
 209     }
 210     // template magic, cppcanvas/source/mtfrenderer/implrenderer.cxx
 211     if (aFunctionName == "cppcanvas::internal::(anonymous namespace)::AreaQuery::result") {
 212         return true;
 213     }
 214     // callback, drawinglayer/source/dumper/XShapeDumper.
 215     if (aFunctionName == "(anonymous namespace)::closeCallback") {
 216         return true;
 217     }
 218     // callback, basic/source/runtime/runtime.cxx
 219     if (aFunctionName == "SbiRuntime::StepNOP") {
 220         return true;
 221     }
 222     // DLL stuff, only used on windows, basic/source/runtime/dllmgr.hxx
 223     if (aFunctionName == "SbiDllMgr::FreeDll") {
 224         return true;
 225     }
 226     // only used on Windows, basic/source/sbx/sbxdec.cxx
 227     if (aFunctionName == "SbxDecimal::neg" || aFunctionName == "SbxDecimal::isZero") {
 228         return true;
 229     }
 230     // used as a callback, include/sfx2/shell.hxx
 231     if (aFunctionName == "SfxShell::EmptyExecStub" || aFunctionName == "SfxShell::EmptyStateStub"
 232         || aFunctionName == "SfxShell::VerbState") {
 233         return true;
 234     }
 235     // SFX_IMPL_POS_CHILDWINDOW_WITHID macro
 236     if (aFunctionName.find("GetChildWindowId") != std::string::npos) {
 237         return true;
 238     }
 239     // SFX_IMPL_SUPERCLASS_INTERFACE macro
 240     if (aFunctionName.find("InitInterface_Impl") != std::string::npos) {
 241         return true;
 242     }
 243     // callback, vcl/unx/generic/app/sm.cxx
 244     if (aFunctionName == "IgnoreIceIOErrors" || aFunctionName == "IgnoreIceErrors") {
 245         return true;
 246     }
 247     // callback, vcl/unx/gtk/a11y/atkcomponent.cxx
 248     if (aFunctionName == "component_wrapper_get_mdi_zorder") {
 249         return true;
 250     }
 251     // callback, vcl/unx/gtk/a11y/atkaction.cxx
 252     if (aFunctionName == "action_wrapper_set_description") {
 253         return true;
 254     }
 255     // callback, vcl/unx/gtk/a11y/atkutil.cxx
 256     if (aFunctionName == "ooo_atk_util_get_toolkit_version" || aFunctionName == "ooo_atk_util_get_toolkit_name") {
 257         return true;
 258     }
 259     // callback, vcl/unx/gtk/a11y/atktextattributes.cxx
 260     if (aFunctionName == "InvalidValue") {
 261         return true;
 262     }
 263     // callback, vcl/unx/gtk/a11y/atktable.cxx
 264     if (aFunctionName == "table_wrapper_set_summary" || aFunctionName == "table_wrapper_set_row_header"
 265         || aFunctionName == "table_wrapper_set_row_description"
 266         || aFunctionName == "table_wrapper_set_column_header"
 267         || aFunctionName == "table_wrapper_set_column_description"
 268         || aFunctionName == "table_wrapper_set_caption") {
 269         return true;
 270     }
 271     // callbacks, vcl/unx/gtk/window/gtksalframe.cxx
 272     if (startsWith(aFunctionName, "GtkSalFrame::IMHandler::signal")) {
 273         return true;
 274     }
 275     // callbacks, vcl/unx/gtk/window/glomenu.cxx
 276     if (startsWith(aFunctionName, "g_lo_menu_is_mutable")) {
 277         return true;
 278     }
 279     // only contains code for certain versions of GTK, /vcl/unx/gtk/window/gtksalframe.cx
 280     if (aFunctionName == "GtkSalFrame::AllocateFrame") {
 281         return true;
 282     }
 283     // only valid for Windows, embeddedobj/source/msole/olemisc.cxx
 284     if (aFunctionName == "OleEmbeddedObject::GetRidOfComponent") {
 285         return true;
 286     }
 287     // callback, svx/source/accessibility/ShapeTypeHandler.cxx
 288     if (aFunctionName == "accessibility::CreateEmptyShapeReference") {
 289         return true;
 290     }
 291     //  chart2/source/view/main/AbstractShapeFactory.cxx
 292     if (aFunctionName == "chart::(anonymous namespace)::thisModule") {
 293         return true;
 294     }
 295     //  chart2/source/tools/InternalData.cxx
 296     if (aFunctionName == "chart::InternalData::dump") {
 297         return true;
 298     }
 299     //  hwpfilter/
 300     if (aFunctionName == "debug" || aFunctionName == "token_debug") {
 301         return true;
 302     }
 303     //  callback, sdext/source/presenter/PresenterFrameworkObserver.cxx
 304     if (aFunctionName == "sdext::presenter::PresenterFrameworkObserver::True") {
 305         return true;
 306     }
 307     // callback, sw/source/core/doc/tblrwcl.cxx
 308     if (aFunctionName == "lcl_DelOtherBox") {
 309         return true;
 310     }
 311     // callback, sw/source/filter/ww8/ww8par.cxx
 312     if (aFunctionName == "SwWW8ImplReader::Read_Majority") {
 313         return true;
 314     }
 315     // callback, sw/source/filter/ww8/ww8par5.cxx
 316     if (aFunctionName == "SwWW8ImplReader::Read_F_Shape") {
 317         return true;
 318     }
 319     // called from SDI file, I don't know what that stuff is about, sd/source/ui/slidesorter/shell/SlideSorterViewShell.cx
 320     if (aFunctionName == "sd::slidesorter::SlideSorterViewShell::ExecStatusBar"
 321         || aFunctionName == "sd::OutlineViewShell::ExecStatusBar") {
 322         return true;
 323     }
 324     // only used in debug mode, sd/source/filter/ppt/pptinanimations.cxx
 325     if (startsWith(aFunctionName, "ppt::AnimationImporter::dump")) {
 326         return true;
 327     }
 328     // only used in ENABLE_SDREMOTE_BLUETOOTH mode, sd/source/ui/dlg/tpoption.cx
 329     if (aFunctionName == "SdTpOptionsMisc::SetImpressMode") {
 330         return true;
 331     }
 332     // template magic, sc/source/ui/docshell/datastream.cxx
 333     if (startsWith(aFunctionName, "sc::(anonymous namespace)::CSVHandler::")) {
 334         return true;
 335     }
 336     // called from SDI file, I don't know what that stuff is about, sc/source/ui/view/cellsh4.cxx
 337     if (aFunctionName == "ScCellShell::GetStateCursor") {
 338         return true;
 339     }
 340     // template magic, sc/source/filter/excel/xepivot.cxx
 341     if (aFunctionName == "XclExpPivotCache::SaveXml") {
 342         return true;
 343     }
 344     // template magic, sc/source/filter/html/htmlpars.cxx
 345     if (startsWith(aFunctionName, "(anonymous namespace)::CSSHandler::")) {
 346         return true;
 347     }
 348     // callbacks, sc/source/filter/oox/formulaparser.cxx
 349     if (startsWith(aFunctionName, "oox::xls::BiffFormulaParserImpl::import")) {
 350         return true;
 351     }
 352     // template magic, sc/qa/unit/helper/csv_handler.hxx
 353     if (startsWith(aFunctionName, "csv_handler::") || startsWith(aFunctionName, "conditional_format_handler::")) {
 354         return true;
 355     }
 356     // template magic, slideshow/source/inc/listenercontainer.hxx
 357     if (startsWith(aFunctionName, "slideshow::internal::EmptyBase::EmptyClearableGuard::")) {
 358         return true;
 359     }
 360     // callback, scripting/source/vbaevents/eventhelper.cxx
 361     if (aFunctionName == "ApproveAll") {
 362         return true;
 363     }
 364     // only on WNT, basic/qa/cppunit/test_vba.cx
 365     if (aFunctionName == "(anonymous namespace)::VBATest::testMiscOLEStuff") {
 366         return true;
 367     }
 368     // GtkSalFrame::TriggerPaintEvent() is only compiled under certain versions of GTK
 369     if (aFunctionName == "GtkSalFrame::TriggerPaintEvent") {
 370         return true;
 371     }
 372     if (aFunctionName == "SwVectorModifyBase::dumpAsXml") {
 373         return true;
 374     }
 375     // vcl/unx/gtk3 re-using vcl/unx/gtk:
 376     if (aFunctionName == "DeInitAtkBridge"
 377         || aFunctionName == "GtkData::initNWF"
 378         || aFunctionName == "GtkSalFrame::EnsureAppMenuWatch"
 379         || aFunctionName == "InitAtkBridge")
 380     {
 381         return true;
 382     }
 383     if (aFunctionName == "sc::AlignedAllocator::operator!=") {
 384         return true;
 385     }
 386     if (aFunctionName == "clipboard_owner_init") {
 387         return true;
 388     }
 389     // returns sizeof(struct) vcl/source/gdi/dibtools.cxx
 390     if (aFunctionName == "getDIBV5HeaderSize") {
 391         return true;
 392     }
 393     // windows only
 394     if (aFunctionName == "InitAccessBridge") {
 395         return true;
 396     }
 397     // callbacks
 398     if (aFunctionName == "disabled_initSystray" || aFunctionName == "disabled_deInitSystray") {
 399         return true;
 400     }
 401     // behind a BREAKPAD option
 402     if (aFunctionName == "desktop::(anonymous namespace)::crashReportInfoExists") {
 403         return true;
 404     }
 405     // LOK stuff
 406     if (aFunctionName == "doc_getTileMode") {
 407         return true;
 408     }
 409     // apparently this will be useful at sometime in the future
 410     if (aFunctionName == "LocaleDataWrapper::getCurrZeroChar") {
 411         return true;
 412     }
 413     // marked with TODO
 414     if (aFunctionName == "oglcanvas::TextLayout::draw") {
 415         return true;
 416     }
 417     // called from the .sdi files
 418     if (aFunctionName == "SfxObjectShell::StateView_Impl") {
 419         return true;
 420     }
 421     // gtk callback
 422     if (aFunctionName == "GtkSalFrame::signalVisibility") {
 423         return true;
 424     }
 425     // platform-version-dependent code
 426     if (aFunctionName == "(anonymous namespace)::ACTIVE_TAB") {
 427         return true;
 428     }
 429     // SMIL callbacks
 430     if (aFunctionName == "boost::sp_scalar_constructor_hook" || aFunctionName == "boost::sp_scalar_destructor_hook") {
 431         return true;
 432     }
 433
 434
 435
 436
 437     std::string aImmediateMacro = "";
 438     if (compiler.getSourceManager().isMacroBodyExpansion(pFunctionDecl->getLocStart()) ) {
 439         StringRef name { Lexer::getImmediateMacroName(
 440                 pFunctionDecl->getLocStart(), compiler.getSourceManager(), compiler.getLangOpts()) };
 441         aImmediateMacro = name;
 442         if (name.startswith("IMPL_LINK_") )
 443         {
 444             return true;
 445         }
 446     }
 447
 448     const CompoundStmt *pCompoundStmt = dyn_cast<CompoundStmt>(pFunctionDecl->getBody());
 449     bool bEmptyBody = false;
 450     if (pCompoundStmt) {
 451         if (pCompoundStmt->size() > 1) {
 452             return true;
 453         }
 454         if (pCompoundStmt->size() > 0) {
 455             const ReturnStmt *pReturnStmt = dyn_cast<ReturnStmt>(*pCompoundStmt->body_begin());
 456             if (!pReturnStmt) {
 457                 return true;
 458             }
 459             if (const UnaryOperator* unaryOp = dyn_cast<UnaryOperator>(pReturnStmt->getRetValue())) {
 460                 if (unaryOp->getOpcode() == UO_AddrOf) {
 461                     return true;
 462                 }
 463             }
 464             if (pReturnStmt->getRetValue() != nullptr) {
 465                 // && !pReturnStmt->getRetValue()->isEvaluatable(compiler.getASTContext())) {
 466                 bool aBoolResult;
 467                 llvm::APSInt aIntResult;
 468                 if (pReturnStmt->getRetValue()->isTypeDependent()
 469                     || (!pReturnStmt->getRetValue()->EvaluateAsBooleanCondition(aBoolResult, compiler.getASTContext())
 470                         && !pReturnStmt->getRetValue()->EvaluateAsInt(aIntResult, compiler.getASTContext())))
 471                 {
 472                     return true;
 473                 }
 474             }
 475         } else {
 476             bEmptyBody = true;
 477         }
 478     }
 479
 480     std::string aMessage = "this ";
 481     aMessage += pCXXMethodDecl ? "method" : "function";
 482     if (bEmptyBody) {
 483         aMessage += " is empty and should be removed, " + aFunctionName;
 484     } else {
 485         aMessage += " returns a constant value and should be converted to a constant "
 486                     "or to static inline, " + aFunctionName + ", " + aImmediateMacro;
 487     }
 488     report(
 489         DiagnosticsEngine::Warning,
 490         aMessage,
 491         pFunctionDecl->getLocStart())
 492       << pFunctionDecl->getSourceRange();
 493     if (pFunctionDecl != pFunctionDecl->getCanonicalDecl())
 494         report(
 495             DiagnosticsEngine::Note,
 496             aMessage,
 497             pFunctionDecl->getCanonicalDecl()->getLocStart())
 498           << pFunctionDecl->getCanonicalDecl()->getSourceRange();
 499     return true;
 500 }
 501
 502 loplugin::Plugin::Registration<ConstantFunction> X("constantfunction");
 503
 504 }
 505
 506 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */