compilerplugins/clang/staticvar.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 <cassert>
  11 #include <string>
  12 #include <iostream>
  13 #include <unordered_map>
  14 #include <unordered_set>
  15
  16 #include "plugin.hxx"
  17 #include "check.hxx"
  18 #include "clang/AST/CXXInheritance.h"
  19 #include "clang/AST/StmtVisitor.h"
  20
  21 // Look for variables that either
  22 // (a) could be statically initialised, without runtime code, and warn
  23 // (b) variables that are statically declared, but require runtime initialisation, and warn
  24 //
  25 // e.g.
  26 //     static const OUString[] XXX { "xxx" };
  27 // requires runtime initialisation, so should rather be declared as OUStringLiteral
  28 // and
  29 //     static int[] XXX { 1,2 };
  30 // can be declared const since it does not require runtime initialisation.
  31
  32 namespace
  33 {
  34 class StaticVar : public loplugin::FilteringPlugin<StaticVar>
  35 {
  36 public:
  37     explicit StaticVar(loplugin::InstantiationData const& data)
  38         : FilteringPlugin(data)
  39     {
  40     }
  41
  42     virtual void run() override
  43     {
  44         std::string fn(handler.getMainFileName());
  45         loplugin::normalizeDotDotInFilePath(fn);
  46
  47         if (
  48             // uses icu::UnicodeString
  49             fn == SRCDIR "/l10ntools/source/xmlparse.cxx"
  50             // contains mutable state
  51             || fn == SRCDIR "/sal/osl/unx/signal.cxx"
  52             || fn == SRCDIR "/sal/qa/rtl/digest/rtl_digest.cxx"
  53             || fn == SRCDIR "/sal/qa/rtl/strings/test_oustring_endswith.cxx"
  54             || fn == SRCDIR "/sal/qa/rtl/strings/test_oustring_convert.cxx"
  55             || fn == SRCDIR "/svl/qa/unit/items/test_itempool.cxx"
  56             // contains mutable state
  57             || fn == SRCDIR "/vcl/unx/generic/dtrans/X11_selection.cxx"
  58             || fn == SRCDIR "/sax/qa/cppunit/xmlimport.cxx"
  59             || fn == SRCDIR "/pyuno/source/module/pyuno.cxx"
  60             || fn == SRCDIR "/pyuno/source/module/pyuno_module.cxx"
  61             || fn == SRCDIR "/pyuno/source/module/pyuno_struct.cxx"
  62             // TODO for this one we need a static OUString
  63             || fn == SRCDIR "/xmloff/source/core/xmltoken.cxx"
  64             // mutable
  65             || fn == SRCDIR "/basic/source/runtime/stdobj.cxx"
  66             // TODO this needs more extensive cleanup
  67             || fn == SRCDIR "/connectivity/source/drivers/postgresql/pq_statics.cxx"
  68             // mutable
  69             || fn == SRCDIR "/hwpfilter/source/hwpreader.cxx"
  70             // mutable
  71             || fn == SRCDIR "/sw/source/filter/basflt/fltini.cxx"
  72             // mutable
  73             || fn == SRCDIR "/sw/source/uibase/docvw/srcedtw.cxx"
  74             // mutable
  75             || fn == SRCDIR "/forms/source/misc/limitedformats.cxx"
  76             // aHTMLOptionTab is ordered by useful grouping, so let it sort at runtime
  77             || fn == SRCDIR "/svtools/source/svhtml/htmlkywd.cxx"
  78             // TODO sorting some of these tables will be a lot of work...
  79             || fn == SRCDIR "/sw/source/filter/ww8/ww8par6.cxx"
  80             // this only triggers on older versions of clang, not sure why
  81             // in any case, it is actually about the array in vcl/inc/units.hrc, which we can't change
  82             || fn == SRCDIR "/vcl/source/app/svdata.cxx"
  83             // I tried doing this, but got very weird unit test failures, apparently sorting this table
  84             // disturbs some code elsewhere
  85             || fn == SRCDIR "/svx/source/unodraw/unoprov.cxx"
  86             // aRTFTokenTab is ordered by useful grouping, so let it sort at runtime
  87             || fn == SRCDIR "/svtools/source/svrtf/rtfkeywd.cxx")
  88             return;
  89         TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
  90     }
  91
  92     bool VisitVarDecl(VarDecl const*);
  93 };
  94
  95 static bool containsNonLiteral(Expr const* expr)
  96 {
  97     expr = expr->IgnoreImplicit();
  98     if (auto initList = dyn_cast<InitListExpr>(expr))
  99     {
 100         for (unsigned i = 0; i < initList->getNumInits(); ++i)
 101             if (containsNonLiteral(initList->getInit(i)))
 102                 return true;
 103     }
 104     else if (auto constructExpr = dyn_cast<CXXConstructExpr>(expr))
 105     {
 106         for (Expr const* arg : constructExpr->arguments())
 107             if (containsNonLiteral(arg))
 108                 return true;
 109     }
 110     else if (isa<MemberExpr>(expr))
 111         return true;
 112     else if (auto declRefExpr = dyn_cast<DeclRefExpr>(expr))
 113     {
 114         auto varDecl = dyn_cast_or_null<VarDecl>(declRefExpr->getDecl());
 115         return varDecl && varDecl->isLocalVarDeclOrParm();
 116     }
 117     else if (isa<CXXMemberCallExpr>(expr))
 118         return true;
 119     else if (auto castExpr = dyn_cast<CXXFunctionalCastExpr>(expr))
 120         return containsNonLiteral(castExpr->getSubExpr());
 121     else if (auto unaryOp = dyn_cast<UnaryOperator>(expr))
 122         return containsNonLiteral(unaryOp->getSubExpr());
 123
 124     return false;
 125 }
 126
 127 bool StaticVar::VisitVarDecl(VarDecl const* varDecl)
 128 {
 129     if (ignoreLocation(varDecl))
 130         return true;
 131     if (!varDecl->hasInit())
 132         return true;
 133     auto initList = dyn_cast_or_null<InitListExpr>(varDecl->getInit());
 134     if (!initList)
 135         return true;
 136     if (varDecl->isExceptionVariable() || isa<ParmVarDecl>(varDecl))
 137         return true;
 138     if (!varDecl->getType()->isArrayType())
 139         return true;
 140     auto elementType = varDecl->getType()->getBaseElementTypeUnsafe();
 141     if (!elementType->isRecordType())
 142         return true;
 143     auto elementRecordDecl
 144         = dyn_cast_or_null<CXXRecordDecl>(elementType->getAs<RecordType>()->getDecl());
 145     if (!elementRecordDecl)
 146         return true;
 147     if (containsNonLiteral(initList))
 148         return true;
 149
 150     if (elementRecordDecl->hasTrivialDestructor())
 151     {
 152         if (varDecl->isLocalVarDecl())
 153         {
 154             if (varDecl->getStorageDuration() == SD_Static && varDecl->getType().isConstQualified())
 155                 return true;
 156         }
 157         else
 158         {
 159             if (varDecl->getType().isConstQualified())
 160                 return true;
 161         }
 162
 163         // TODO cannot figure out how to make the loplugin::TypeCheck stuff match this
 164         //    std::string typeName = varDecl->getType().getAsString();
 165         //    if (typeName == "std::va_list" || typeName == "va_list")
 166         //        return true;
 167
 168         auto const tcElement = loplugin::TypeCheck(elementRecordDecl);
 169         if (tcElement.Struct("ContextID_Index_Pair").GlobalNamespace())
 170             return true;
 171         if (tcElement.Class("SfxSlot").GlobalNamespace())
 172             return true;
 173
 174         if (varDecl->isLocalVarDecl())
 175             report(DiagnosticsEngine::Warning, "var should be static const, or whitelisted",
 176                    varDecl->getLocation())
 177                 << varDecl->getSourceRange();
 178         else
 179             report(DiagnosticsEngine::Warning, "var should be const, or whitelisted",
 180                    varDecl->getLocation())
 181                 << varDecl->getSourceRange();
 182     }
 183     else
 184     {
 185         if (varDecl->isLocalVarDecl())
 186         {
 187             if (varDecl->getStorageDuration() != SD_Static
 188                 || !varDecl->getType().isConstQualified())
 189                 return true;
 190         }
 191         else
 192         {
 193             if (!varDecl->getType().isConstQualified())
 194                 return true;
 195         }
 196
 197         if (varDecl->isLocalVarDecl())
 198             report(DiagnosticsEngine::Warning, "static const var requires runtime initialization?",
 199                    varDecl->getLocation())
 200                 << varDecl->getSourceRange();
 201         else
 202             report(DiagnosticsEngine::Warning, "static var requires runtime initialization?",
 203                    varDecl->getLocation())
 204                 << varDecl->getSourceRange();
 205     }
 206     return true;
 207 }
 208
 209 loplugin::Plugin::Registration<StaticVar> X("staticvar", false);
 210 }
 211
 212 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */