build/clang-plugin/MustOverrideChecker.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "MustOverrideChecker.h"
   6 #include "CustomMatchers.h"
   7
   8 void MustOverrideChecker::registerMatchers(MatchFinder *AstMatcher) {
   9   AstMatcher->addMatcher(cxxRecordDecl(isDefinition()).bind("class"), this);
  10 }
  11
  12 void MustOverrideChecker::registerPPCallbacks(CompilerInstance &CI) {
  13   this->CI = &CI;
  14 }
  15
  16 void MustOverrideChecker::check(const MatchFinder::MatchResult &Result) {
  17   auto D = Result.Nodes.getNodeAs<CXXRecordDecl>("class");
  18
  19   // Look through all of our immediate bases to find methods that need to be
  20   // overridden
  21   typedef std::vector<CXXMethodDecl *> OverridesVector;
  22   OverridesVector MustOverrides;
  23   for (const auto &Base : D->bases()) {
  24     // The base is either a class (CXXRecordDecl) or it's a templated class...
  25     CXXRecordDecl *Parent = Base.getType()
  26                                 .getDesugaredType(D->getASTContext())
  27                                 ->getAsCXXRecordDecl();
  28     // The parent might not be resolved to a type yet. In this case, we can't
  29     // do any checking here. For complete correctness, we should visit
  30     // template instantiations, but this case is likely to be rare, so we will
  31     // ignore it until it becomes important.
  32     if (!Parent) {
  33       continue;
  34     }
  35     Parent = Parent->getDefinition();
  36     for (const auto &M : Parent->methods()) {
  37       if (hasCustomAttribute<moz_must_override>(M))
  38         MustOverrides.push_back(M);
  39     }
  40   }
  41
  42   for (auto &O : MustOverrides) {
  43     bool Overridden = false;
  44     for (const auto &M : D->methods()) {
  45       // The way that Clang checks if a method M overrides its parent method
  46       // is if the method has the same name but would not overload.
  47       if (getNameChecked(M) == getNameChecked(O) &&
  48           !CI->getSema().IsOverload(M, O, false)) {
  49         Overridden = true;
  50         break;
  51       }
  52     }
  53     if (!Overridden) {
  54       diag(D->getLocation(), "%0 must override %1", DiagnosticIDs::Error)
  55           << D->getDeclName() << O->getDeclName();
  56       diag(O->getLocation(), "function to override is here",
  57            DiagnosticIDs::Note);
  58     }
  59   }
  60 }