7c50187b7d
Add an option to ignore warnings for cppcoreguidelines avoid-non-const-global-variables. Understandably, the core guidelines discourage non const global variables, even at the TU level (see https://github.com/isocpp/CppCoreGuidelines/issues/2195). However, having a small TU with an interface that uses a non const variable from an anonymous namespace can be a valid choice. This adds an option that disables the warning just for anonymous namespaces, i.e. at the file level. The default is still to show a warning, just as before.
80 lines
3.2 KiB
C++
80 lines
3.2 KiB
C++
//===--- AvoidNonConstGlobalVariablesCheck.cpp - clang-tidy ---------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "AvoidNonConstGlobalVariablesCheck.h"
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#include "clang/ASTMatchers/ASTMatchFinder.h"
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#include "clang/ASTMatchers/ASTMatchers.h"
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using namespace clang::ast_matchers;
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namespace clang::tidy::cppcoreguidelines {
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AvoidNonConstGlobalVariablesCheck::AvoidNonConstGlobalVariablesCheck(
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StringRef Name, ClangTidyContext *Context)
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: ClangTidyCheck(Name, Context),
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AllowInternalLinkage(Options.get("AllowInternalLinkage", false)) {}
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void AvoidNonConstGlobalVariablesCheck::registerMatchers(MatchFinder *Finder) {
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auto NamespaceMatcher = AllowInternalLinkage
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? namespaceDecl(unless(isAnonymous()))
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: namespaceDecl();
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auto GlobalContext =
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varDecl(hasGlobalStorage(),
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hasDeclContext(anyOf(NamespaceMatcher, translationUnitDecl())));
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auto GlobalVariable = varDecl(
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GlobalContext,
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AllowInternalLinkage ? varDecl(unless(isStaticStorageClass()))
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: varDecl(),
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unless(anyOf(
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isConstexpr(), hasType(isConstQualified()),
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hasType(referenceType())))); // References can't be changed, only the
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// data they reference can be changed.
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auto GlobalReferenceToNonConst =
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varDecl(GlobalContext, hasType(referenceType()),
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unless(hasType(references(qualType(isConstQualified())))));
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auto GlobalPointerToNonConst = varDecl(
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GlobalContext, hasType(pointerType(pointee(unless(isConstQualified())))));
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Finder->addMatcher(GlobalVariable.bind("non-const_variable"), this);
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Finder->addMatcher(GlobalReferenceToNonConst.bind("indirection_to_non-const"),
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this);
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Finder->addMatcher(GlobalPointerToNonConst.bind("indirection_to_non-const"),
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this);
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}
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void AvoidNonConstGlobalVariablesCheck::check(
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const MatchFinder::MatchResult &Result) {
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if (const auto *Variable =
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Result.Nodes.getNodeAs<VarDecl>("non-const_variable")) {
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diag(Variable->getLocation(), "variable %0 is non-const and globally "
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"accessible, consider making it const")
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<< Variable; // FIXME: Add fix-it hint to Variable
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// Don't return early, a non-const variable may also be a pointer or
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// reference to non-const data.
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}
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if (const auto *VD =
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Result.Nodes.getNodeAs<VarDecl>("indirection_to_non-const")) {
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diag(VD->getLocation(),
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"variable %0 provides global access to a non-const object; consider "
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"making the %select{referenced|pointed-to}1 data 'const'")
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<< VD
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<< VD->getType()->isPointerType(); // FIXME: Add fix-it hint to Variable
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}
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}
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void AvoidNonConstGlobalVariablesCheck::storeOptions(
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ClangTidyOptions::OptionMap &Opts) {
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Options.store(Opts, "AllowInternalLinkage", AllowInternalLinkage);
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}
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} // namespace clang::tidy::cppcoreguidelines
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