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 "compat.hxx"
  12 #include <iostream>
  13
  14 /*
  15   Look for member functions that merely return a compile-time constant, or they are empty, and can thus
  16   be either removed, or converted into a constant.
  17
  18   This mostly tends to happen as a side-effect of other cleanups.
  19 */
  20 namespace {
  21
  22 class ConstantFunction:
  23     public RecursiveASTVisitor<ConstantFunction>, public loplugin::Plugin
  24 {
  25     StringRef getFilename(SourceLocation loc);
  26 public:
  27     explicit ConstantFunction(InstantiationData const & data): Plugin(data) {}
  28
  29     void run() override
  30     {
  31         // these files crash clang-3.5 somewhere in the isEvaluatable/EvaluateAsXXX stuff
  32         FileID mainFileID = compiler.getSourceManager().getMainFileID();
  33         if (strstr(compiler.getSourceManager().getFileEntryForID(mainFileID)->getDir()->getName(), "sc/source/core/data") != 0) {
  34             return;
  35         }
  36         if (strstr(compiler.getSourceManager().getFileEntryForID(mainFileID)->getDir()->getName(), "sc/source/ui/app") != 0) {
  37             return;
  38         }
  39         if (strstr(compiler.getSourceManager().getFileEntryForID(mainFileID)->getDir()->getName(), "sc/qa/unit") != 0) {
  40             return;
  41         }
  42         if (strstr(compiler.getSourceManager().getFileEntryForID(mainFileID)->getName(), "docuno.cxx") != 0) {
  43             return;
  44         }
  45         if (strstr(compiler.getSourceManager().getFileEntryForID(mainFileID)->getName(), "viewdata.cxx") != 0) {
  46             return;
  47         }
  48         if (strstr(compiler.getSourceManager().getFileEntryForID(mainFileID)->getName(), "calcoptionsdlg.cxx") != 0) {
  49             return;
  50         }
  51         if (strstr(compiler.getSourceManager().getFileEntryForID(mainFileID)->getDir()->getName(), "sc/source/core/opencl") != 0) {
  52             return;
  53         }
  54         if (strstr(compiler.getSourceManager().getFileEntryForID(mainFileID)->getDir()->getName(), "sc/source/core/tool") != 0) {
  55             return;
  56         }
  57
  58         TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
  59     }
  60
  61     bool VisitFunctionDecl(const FunctionDecl *);
  62 };
  63
  64 StringRef ConstantFunction::getFilename(SourceLocation loc)
  65 {
  66     SourceLocation spellingLocation = compiler.getSourceManager().getSpellingLoc(loc);
  67     StringRef name { compiler.getSourceManager().getFilename(spellingLocation) };
  68     return name;
  69 }
  70
  71 static bool startsWith(const std::string& rStr, const char* pSubStr) {
  72     return rStr.compare(0, strlen(pSubStr), pSubStr) == 0;
  73 }
  74
  75 bool ConstantFunction::VisitFunctionDecl(const FunctionDecl * pFunctionDecl) {
  76     if (ignoreLocation(pFunctionDecl)) {
  77         return true;
  78     }
  79     if (!pFunctionDecl->hasBody()) {
  80         return true;
  81     }
  82     // stuff declared extern-C is almost always used as a some kind of callback
  83     if (pFunctionDecl->isExternC()) {
  84         return true;
  85     }
  86
  87     StringRef aFileName = getFilename(pFunctionDecl->getLocStart());
  88
  89     // various tests in here are empty stubs under Linux
  90     if (aFileName.startswith(SRCDIR "/sal/qa/")) {
  91         return true;
  92     }
  93     // lots of empty stuff here where it looks like someone is still going to "fill in the blanks"
  94     if (aFileName.startswith(SRCDIR "/basegfx/test/")) {
  95         return true;
  96     }
  97     // some stuff is just stubs under Linux, although this appears to be a SOLARIS-specific hack, so it
  98     // should probably not even be compiling under Linux.
  99     if (aFileName == SRCDIR "/setup_native/scripts/source/getuid.c") {
 100         return true;
 101     }
 102     // bridges has some weird stuff in it....
 103     if (aFileName.startswith(SRCDIR "/bridges/")) {
 104         return true;
 105     }
 106     // dummy implementation of DDE, since it is only active on Windows
 107     if (aFileName == SRCDIR "/svl/unx/source/svdde/ddedummy.cxx"
 108         || aFileName == SRCDIR "/include/svl/svdde.hxx") {
 109         return true;
 110     }
 111     // fancy templates at work here
 112     if (aFileName == SRCDIR "/vcl/source/gdi/bmpfast.cxx") {
 113         return true;
 114     }
 115     // bunch of stuff used as callbacks here
 116     if (aFileName == SRCDIR "/vcl/generic/glyphs/gcach_layout.cxx") {
 117         return true;
 118     }
 119     // salplug runtime-loading mechanism at work
 120     if (getFilename(pFunctionDecl->getCanonicalDecl()->getLocStart()) == SRCDIR "/vcl/inc/salinst.hxx") {
 121         return true;
 122     }
 123     // lots of callbacks here
 124     if (aFileName == SRCDIR "/extensions/source/plugin/unx/npnapi.cxx") {
 125         return true;
 126     }
 127     // template magic
 128     if (aFileName == SRCDIR "/filter/source/svg/svgreader.cxx") {
 129         return true;
 130     }
 131     // vcl/unx/gtk3 re-using vcl/unx/gtk:
 132     if (aFileName.find("/../../gtk/") != std::string::npos) {
 133         return true;
 134     }
 135     // used by code generated by python
 136     if (getFilename(pFunctionDecl->getCanonicalDecl()->getLocStart()) == SRCDIR "/writerfilter/source/ooxml/OOXMLFastContextHandler.hxx") {
 137         return true;
 138     }
 139
 140
 141     const CXXMethodDecl *pCXXMethodDecl = dyn_cast<CXXMethodDecl>(pFunctionDecl);
 142     if (pCXXMethodDecl) {
 143         if (pCXXMethodDecl->isVirtual()) {
 144             return true;
 145         }
 146         // static with inline body will be optimised at compile-time to a constant anyway
 147         if (pCXXMethodDecl->isStatic() && pCXXMethodDecl->hasInlineBody()) {
 148             return true;
 149         }
 150         // this catches some stuff in templates
 151         if (pFunctionDecl->hasAttr<OverrideAttr>()) {
 152             return true;
 153         }
 154     }
 155     // a free function with an inline body will be optimised at compile-time to a constant anyway
 156     if (!pCXXMethodDecl && pFunctionDecl->isInlineSpecified()) {
 157         return true;
 158     }
 159     if (isa<CXXConstructorDecl>(pFunctionDecl) || isa<CXXDestructorDecl>(pFunctionDecl) || isa<CXXConversionDecl>(pFunctionDecl)) {
 160         return true;
 161     }
 162     SourceLocation canonicalLoc = pFunctionDecl->getCanonicalDecl()->getLocStart();
 163     if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(canonicalLoc))) {
 164         return true;
 165     }
 166
 167     switch (pFunctionDecl->getOverloadedOperator()) {
 168     case OO_Delete:
 169     case OO_EqualEqual:
 170     case OO_Call:
 171         return true;
 172     default:
 173         break;
 174     }
 175
 176     std::string aFunctionName = pFunctionDecl->getQualifiedNameAsString();
 177
 178     // something to do with dynamic loading in sal/textenc/textenc.cxx
 179     if (aFunctionName == "thisModule") {
 180         return true;
 181     }
 182     // an empty stub under certain conditions, sal/osl/unx/thread.cxx
 183     if (aFunctionName == "osl_thread_priority_init_Impl") {
 184         return true;
 185     }
 186     // a pointer to this function is taken and passed to an underlying API, shell/source/unix/sysshell/recently_used_file_handler.cxx
 187     if (aFunctionName == "(anonymous namespace)::recently_used_item::set_nothing") {
 188         return true;
 189     }
 190     // a pointer to this function is taken and passed to an underlying API, cppu/source/uno/lbenv.cxx
 191     if (aFunctionName == "defenv_dispose") {
 192         return true;
 193     }
 194     // a pointer to this function is taken and passed to an underlying API, cppuhelper/source/exc_thrower.cxx
 195     if (aFunctionName == "ExceptionThrower_acquire_release_nop") {
 196         return true;
 197     }
 198     // differetnt hook function is called on different platforms, /vcl/source/app/svmainhook.cxx
 199     if (aFunctionName == "ImplSVMainHook") {
 200         return true;
 201     }
 202     // used as a callback, /vcl/source/filter/jpeg/JpegReader.cxx
 203     if (aFunctionName == "term_source") {
 204         return true;
 205     }
 206     // only valid for windows, extensions/source/update/check/updatecheck.cxx
 207     if (aFunctionName == "(anonymous namespace)::UpdateCheckThread::hasInternetConnection") {
 208         return true;
 209     }
 210     // used as callback, extensions/source/plugin/unx/npwrap.cxx
 211     if (aFunctionName == "plugin_x_error_handler" || aFunctionName == "noClosure") {
 212         return true;
 213     }
 214     // used as callback, sax/source/expatwrap/sax_expat.cxx
 215     if (aFunctionName == "(anonymous namespace)::SaxExpatParser_Impl::callbackUnknownEncoding") {
 216         return true;
 217     }
 218     // used as callback, i18npool/source/textconversion/textconversion.cxx
 219     if (aFunctionName == "com::sun::star::i18n::nullFunc") {
 220         return true;
 221     }
 222     // used as callback, xmloff/source/text/txtparae.cxx
 223     if (aFunctionName == "(anonymous namespace)::lcl_TextContentsUnfiltered") {
 224         return true;
 225     }
 226     // template magic, include/canvas/verifyinput.hxx
 227     if (aFunctionName == "canvas::tools::verifyInput") {
 228         return true;
 229     }
 230     // template magic, cppcanvas/source/mtfrenderer/implrenderer.cxx
 231     if (aFunctionName == "cppcanvas::internal::(anonymous namespace)::AreaQuery::result") {
 232         return true;
 233     }
 234     // callback, drawinglayer/source/dumper/XShapeDumper.
 235     if (aFunctionName == "(anonymous namespace)::closeCallback") {
 236         return true;
 237     }
 238     // callback, basic/source/runtime/runtime.cxx
 239     if (aFunctionName == "SbiRuntime::StepNOP") {
 240         return true;
 241     }
 242     // DLL stuff, only used on windows, basic/source/runtime/dllmgr.hxx
 243     if (aFunctionName == "SbiDllMgr::FreeDll") {
 244         return true;
 245     }
 246     // only used on Windows, basic/source/sbx/sbxdec.cxx
 247     if (aFunctionName == "SbxDecimal::neg" || aFunctionName == "SbxDecimal::isZero") {
 248         return true;
 249     }
 250     // used as a callback, include/sfx2/shell.hxx
 251     if (aFunctionName == "SfxShell::EmptyExecStub" || aFunctionName == "SfxShell::EmptyStateStub"
 252         || aFunctionName == "SfxShell::VerbState") {
 253         return true;
 254     }
 255     // SFX_IMPL_POS_CHILDWINDOW_WITHID macro
 256     if (aFunctionName.find("GetChildWindowId") != std::string::npos) {
 257         return true;
 258     }
 259     // SFX_IMPL_SUPERCLASS_INTERFACE macro
 260     if (aFunctionName.find("InitInterface_Impl") != std::string::npos) {
 261         return true;
 262     }
 263     // callback, vcl/unx/generic/app/sm.cxx
 264     if (aFunctionName == "IgnoreIceIOErrors" || aFunctionName == "IgnoreIceErrors") {
 265         return true;
 266     }
 267     // callback, vcl/unx/gtk/a11y/atkcomponent.cxx
 268     if (aFunctionName == "component_wrapper_get_mdi_zorder") {
 269         return true;
 270     }
 271     // callback, vcl/unx/gtk/a11y/atkaction.cxx
 272     if (aFunctionName == "action_wrapper_set_description") {
 273         return true;
 274     }
 275     // callback, vcl/unx/gtk/a11y/atkutil.cxx
 276     if (aFunctionName == "ooo_atk_util_get_toolkit_version" || aFunctionName == "ooo_atk_util_get_toolkit_name") {
 277         return true;
 278     }
 279     // callback, vcl/unx/gtk/a11y/atktextattributes.cxx
 280     if (aFunctionName == "InvalidValue") {
 281         return true;
 282     }
 283     // callback, vcl/unx/gtk/a11y/atktable.cxx
 284     if (aFunctionName == "table_wrapper_set_summary" || aFunctionName == "table_wrapper_set_row_header"
 285         || aFunctionName == "table_wrapper_set_row_description"
 286         || aFunctionName == "table_wrapper_set_column_header"
 287         || aFunctionName == "table_wrapper_set_column_description"
 288         || aFunctionName == "table_wrapper_set_caption") {
 289         return true;
 290     }
 291     // callbacks, vcl/unx/gtk/window/gtksalframe.cxx
 292     if (startsWith(aFunctionName, "GtkSalFrame::IMHandler::signal")) {
 293         return true;
 294     }
 295     // callbacks, vcl/unx/gtk/window/glomenu.cxx
 296     if (startsWith(aFunctionName, "g_lo_menu_is_mutable")) {
 297         return true;
 298     }
 299     // only contains code for certain versions of GTK, /vcl/unx/gtk/window/gtksalframe.cx
 300     if (aFunctionName == "GtkSalFrame::AllocateFrame") {
 301         return true;
 302     }
 303     // only valid for Windows, embeddedobj/source/msole/olemisc.cxx
 304     if (aFunctionName == "OleEmbeddedObject::GetRidOfComponent") {
 305         return true;
 306     }
 307     // callback, svx/source/accessibility/ShapeTypeHandler.cxx
 308     if (aFunctionName == "accessibility::CreateEmptyShapeReference") {
 309         return true;
 310     }
 311     //  chart2/source/view/main/AbstractShapeFactory.cxx
 312     if (aFunctionName == "chart::(anonymous namespace)::thisModule") {
 313         return true;
 314     }
 315     //  chart2/source/tools/InternalData.cxx
 316     if (aFunctionName == "chart::InternalData::dump") {
 317         return true;
 318     }
 319     //  hwpfilter/
 320     if (aFunctionName == "debug" || aFunctionName == "token_debug") {
 321         return true;
 322     }
 323     //  callback, sdext/source/presenter/PresenterFrameworkObserver.cxx
 324     if (aFunctionName == "sdext::presenter::PresenterFrameworkObserver::True") {
 325         return true;
 326     }
 327     //  hidden behind the ENABLE_PANE_RESIZING macro
 328     if (aFunctionName == "sdext::presenter::PresenterWindowManager::UpdateWindowList") {
 329         return true;
 330     }
 331     // callback, sw/source/core/doc/tblrwcl.cxx
 332     if (aFunctionName == "lcl_DelOtherBox") {
 333         return true;
 334     }
 335     // callback, sw/source/filter/ww8/ww8par.cxx
 336     if (aFunctionName == "SwWW8ImplReader::Read_Majority") {
 337         return true;
 338     }
 339     // callback, sw/source/filter/ww8/ww8par5.cxx
 340     if (aFunctionName == "SwWW8ImplReader::Read_F_Shape") {
 341         return true;
 342     }
 343     // called from SDI file, I don't know what that stuff is about, sd/source/ui/slidesorter/shell/SlideSorterViewShell.cx
 344     if (aFunctionName == "sd::slidesorter::SlideSorterViewShell::ExecStatusBar"
 345         || aFunctionName == "sd::OutlineViewShell::ExecStatusBar") {
 346         return true;
 347     }
 348     // only used in debug mode, sd/source/filter/ppt/pptinanimations.cxx
 349     if (startsWith(aFunctionName, "ppt::AnimationImporter::dump")) {
 350         return true;
 351     }
 352     // only used in ENABLE_SDREMOTE_BLUETOOTH mode, sd/source/ui/dlg/tpoption.cx
 353     if (aFunctionName == "SdTpOptionsMisc::SetImpressMode") {
 354         return true;
 355     }
 356     // template magic, sc/source/ui/docshell/datastream.cxx
 357     if (startsWith(aFunctionName, "sc::(anonymous namespace)::CSVHandler::")) {
 358         return true;
 359     }
 360     // called from SDI file, I don't know what that stuff is about, sc/source/ui/docshell/docsh7.cxx
 361     if (aFunctionName == "ScDocShell::GetDrawObjState") {
 362         return true;
 363     }
 364     // called from SDI file, I don't know what that stuff is about, sc/source/ui/view/cellsh4.cxx
 365     if (aFunctionName == "ScCellShell::GetStateCursor") {
 366         return true;
 367     }
 368     // called from SDI file, I don't know what that stuff is about, sc/source/ui/view/tabvwshh.cxx
 369     if (aFunctionName == "ScTabViewShell::ExecuteSbx" || aFunctionName == "ScTabViewShell::GetSbxState") {
 370         return true;
 371     }
 372     // template magic, sc/source/filter/excel/xepivot.cxx
 373     if (aFunctionName == "XclExpPivotCache::SaveXml") {
 374         return true;
 375     }
 376     // template magic, sc/source/filter/html/htmlpars.cxx
 377     if (startsWith(aFunctionName, "(anonymous namespace)::CSSHandler::")) {
 378         return true;
 379     }
 380     // callbacks, sc/source/filter/oox/formulaparser.cxx
 381     if (startsWith(aFunctionName, "oox::xls::BiffFormulaParserImpl::import")) {
 382         return true;
 383     }
 384     // template magic, sc/qa/unit/helper/csv_handler.hxx
 385     if (startsWith(aFunctionName, "csv_handler::") || startsWith(aFunctionName, "conditional_format_handler::")) {
 386         return true;
 387     }
 388     // template magic, slideshow/source/inc/listenercontainer.hxx
 389     if (startsWith(aFunctionName, "slideshow::internal::EmptyBase::EmptyClearableGuard::")) {
 390         return true;
 391     }
 392     // callback, scripting/source/vbaevents/eventhelper.cxx
 393     if (aFunctionName == "ApproveAll") {
 394         return true;
 395     }
 396     // only on WNT, basic/qa/cppunit/test_vba.cx
 397     if (aFunctionName == "(anonymous namespace)::VBATest::testMiscOLEStuff") {
 398         return true;
 399     }
 400     // GtkSalFrame::TriggerPaintEvent() is only compiled under certain versions of GTK
 401     if (aFunctionName == "GtkSalFrame::TriggerPaintEvent") {
 402         return true;
 403     }
 404     if (aFunctionName == "SwVectorModifyBase::dumpAsXml") {
 405         return true;
 406     }
 407     // vcl/unx/gtk3 re-using vcl/unx/gtk:
 408     if (aFunctionName == "DeInitAtkBridge"
 409         || aFunctionName == "GtkData::initNWF"
 410         || aFunctionName == "GtkSalFrame::EnsureAppMenuWatch"
 411         || aFunctionName == "InitAtkBridge")
 412     {
 413         return true;
 414     }
 415
 416     // can't mess with the TYPEINIT macros in include/tools/rtti.hxx or the LINK macros in include/tools/link.hxx
 417     std::string aImmediateMacro = "";
 418     if (compat::isMacroBodyExpansion(compiler, pFunctionDecl->getLocStart()) ) {
 419         StringRef name { Lexer::getImmediateMacroName(
 420                 pFunctionDecl->getLocStart(), compiler.getSourceManager(), compiler.getLangOpts()) };
 421         aImmediateMacro = name;
 422         if (name == "TYPEINIT_FACTORY" || name == "TYPEINFO" || name == "TYPEINFO_OVERRIDE"
 423             || name.startswith("IMPL_LINK") || name == "DECL_LINK")
 424         {
 425             return true;
 426         }
 427     }
 428
 429     const CompoundStmt *pCompoundStmt = dyn_cast<CompoundStmt>(pFunctionDecl->getBody());
 430     bool aEmptyBody = false;
 431     if (pCompoundStmt) {
 432         if (pCompoundStmt->size() > 1) {
 433             return true;
 434         }
 435         if (pCompoundStmt->size() > 0) {
 436             const ReturnStmt *pReturnStmt = dyn_cast<ReturnStmt>(*pCompoundStmt->body_begin());
 437             if (!pReturnStmt) {
 438                 return true;
 439             }
 440             if (pReturnStmt->getRetValue() != nullptr) {
 441                 // && !pReturnStmt->getRetValue()->isEvaluatable(compiler.getASTContext())) {
 442                 bool aBoolResult;
 443                 llvm::APSInt aIntResult;
 444                 if (pReturnStmt->getRetValue()->isTypeDependent()
 445                     || (!pReturnStmt->getRetValue()->EvaluateAsBooleanCondition(aBoolResult, compiler.getASTContext())
 446                         && !pReturnStmt->getRetValue()->EvaluateAsInt(aIntResult, compiler.getASTContext())))
 447                 {
 448                     return true;
 449                 }
 450             }
 451         } else {
 452             aEmptyBody = true;
 453         }
 454     }
 455
 456     std::string aMessage = "this ";
 457     aMessage += pCXXMethodDecl ? "method" : "function";
 458     if (aEmptyBody) {
 459         aMessage += " is empty and should be removed, " + aFunctionName;
 460     } else {
 461         aMessage += " returns a constant value and should be converted to a constant "
 462                     "or to static inline, " + aFunctionName + ", " + aImmediateMacro;
 463     }
 464     report(
 465         DiagnosticsEngine::Warning,
 466         aMessage,
 467         pFunctionDecl->getLocStart())
 468       << pFunctionDecl->getSourceRange()
 469       << pFunctionDecl->getCanonicalDecl()->getSourceRange();
 470     return true;
 471 }
 472
 473 loplugin::Plugin::Registration<ConstantFunction> X("constantfunction");
 474
 475 }
 476
 477 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */