clang-tools-extra/clang-tidy/cppcoreguidelines/InterfacesGlobalInitCheck.cpp

   1 //===--- InterfacesGlobalInitCheck.cpp - clang-tidy------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "InterfacesGlobalInitCheck.h"
  10 #include "clang/AST/ASTContext.h"
  11 #include "clang/ASTMatchers/ASTMatchFinder.h"
  12
  13 using namespace clang::ast_matchers;
  14
  15 namespace clang::tidy::cppcoreguidelines {
  16
  17 void InterfacesGlobalInitCheck::registerMatchers(MatchFinder *Finder) {
  18   const auto GlobalVarDecl =
  19       varDecl(hasGlobalStorage(),
  20               hasDeclContext(anyOf(translationUnitDecl(), // Global scope.
  21                                    namespaceDecl(),       // Namespace scope.
  22                                    recordDecl())),        // Class scope.
  23               unless(isConstexpr()));
  24
  25   const auto ReferencesUndefinedGlobalVar = declRefExpr(hasDeclaration(
  26       varDecl(GlobalVarDecl, unless(isDefinition())).bind("referencee")));
  27
  28   Finder->addMatcher(
  29       traverse(TK_AsIs, varDecl(GlobalVarDecl, isDefinition(),
  30                                 hasInitializer(expr(hasDescendant(
  31                                     ReferencesUndefinedGlobalVar))))
  32                             .bind("var")),
  33       this);
  34 }
  35
  36 void InterfacesGlobalInitCheck::check(const MatchFinder::MatchResult &Result) {
  37   const auto *const Var = Result.Nodes.getNodeAs<VarDecl>("var");
  38   // For now assume that people who write macros know what they're doing.
  39   if (Var->getLocation().isMacroID())
  40     return;
  41   const auto *const Referencee = Result.Nodes.getNodeAs<VarDecl>("referencee");
  42   // If the variable has been defined, we're good.
  43   const auto *const ReferenceeDef = Referencee->getDefinition();
  44   if (ReferenceeDef != nullptr &&
  45       Result.SourceManager->isBeforeInTranslationUnit(
  46           ReferenceeDef->getLocation(), Var->getLocation())) {
  47     return;
  48   }
  49   diag(Var->getLocation(),
  50        "initializing non-local variable with non-const expression depending on "
  51        "uninitialized non-local variable %0")
  52       << Referencee;
  53 }
  54
  55 } // namespace clang::tidy::cppcoreguidelines