This revision was automatically updated to reflect the committed changes.
Closed by commit rL250537: [clang-tidy] add check
cppcoreguidelines-pro-type-union-access (authored by mgehre).
Changed prior to commit:
http://reviews.llvm.org/D13784?vs=37515&id=37621#toc
Repository:
rL LLVM
http://reviews.llvm.org/D13784
Files:
clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/CMakeLists.txt
clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/ProTypeUnionAccessCheck.cpp
clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/ProTypeUnionAccessCheck.h
clang-tools-extra/trunk/docs/clang-tidy/checks/cppcoreguidelines-pro-type-union-access.rst
clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst
clang-tools-extra/trunk/test/clang-tidy/cppcoreguidelines-pro-type-union-access.cpp
Index: clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/CMakeLists.txt
===================================================================
--- clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/CMakeLists.txt
+++ clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/CMakeLists.txt
@@ -6,6 +6,7 @@
ProTypeConstCastCheck.cpp
ProTypeReinterpretCastCheck.cpp
ProTypeStaticCastDowncastCheck.cpp
+ ProTypeUnionAccessCheck.cpp
LINK_LIBS
clangAST
Index: clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/ProTypeUnionAccessCheck.cpp
===================================================================
--- clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/ProTypeUnionAccessCheck.cpp
+++ clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/ProTypeUnionAccessCheck.cpp
@@ -0,0 +1,33 @@
+//===--- ProTypeUnionAccessCheck.cpp - clang-tidy--------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ProTypeUnionAccessCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+
+void ProTypeUnionAccessCheck::registerMatchers(MatchFinder *Finder) {
+ if (!getLangOpts().CPlusPlus)
+ return;
+
+ Finder->addMatcher(memberExpr(hasObjectExpression(hasType(recordDecl(isUnion())))).bind("expr"), this);
+}
+
+void ProTypeUnionAccessCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *Matched = Result.Nodes.getNodeAs<MemberExpr>("expr");
+ diag(Matched->getMemberLoc(), "do not access members of unions; use (boost::)variant instead");
+}
+
+} // namespace tidy
+} // namespace clang
+
Index: clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
===================================================================
--- clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
+++ clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
@@ -16,6 +16,7 @@
#include "ProTypeConstCastCheck.h"
#include "ProTypeReinterpretCastCheck.h"
#include "ProTypeStaticCastDowncastCheck.h"
+#include "ProTypeUnionAccessCheck.h"
namespace clang {
namespace tidy {
@@ -35,6 +36,8 @@
"cppcoreguidelines-pro-type-reinterpret-cast");
CheckFactories.registerCheck<ProTypeStaticCastDowncastCheck>(
"cppcoreguidelines-pro-type-static-cast-downcast");
+ CheckFactories.registerCheck<ProTypeUnionAccessCheck>(
+ "cppcoreguidelines-pro-type-union-access");
CheckFactories.registerCheck<misc::AssignOperatorSignatureCheck>(
"cppcoreguidelines-c-copy-assignment-signature");
}
Index: clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/ProTypeUnionAccessCheck.h
===================================================================
--- clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/ProTypeUnionAccessCheck.h
+++ clang-tools-extra/trunk/clang-tidy/cppcoreguidelines/ProTypeUnionAccessCheck.h
@@ -0,0 +1,35 @@
+//===--- ProTypeUnionAccessCheck.h - clang-tidy------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_TYPE_UNION_ACCESS_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_TYPE_UNION_ACCESS_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+
+/// This check flags all access to members of unions.
+/// Access to a union as a whole (e.g. passing to a function) is not flagged.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines-pro-type-union-access.html
+class ProTypeUnionAccessCheck : public ClangTidyCheck {
+public:
+ ProTypeUnionAccessCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_TYPE_UNION_ACCESS_H
+
Index: clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst
===================================================================
--- clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst
+++ clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst
@@ -8,6 +8,7 @@
cppcoreguidelines-pro-type-const-cast
cppcoreguidelines-pro-type-reinterpret-cast
cppcoreguidelines-pro-type-static-cast-downcast
+ cppcoreguidelines-pro-type-union-access
google-build-explicit-make-pair
google-build-namespaces
google-build-using-namespace
Index: clang-tools-extra/trunk/docs/clang-tidy/checks/cppcoreguidelines-pro-type-union-access.rst
===================================================================
--- clang-tools-extra/trunk/docs/clang-tidy/checks/cppcoreguidelines-pro-type-union-access.rst
+++ clang-tools-extra/trunk/docs/clang-tidy/checks/cppcoreguidelines-pro-type-union-access.rst
@@ -0,0 +1,9 @@
+cppcoreguidelines-pro-type-union-access
+=======================================
+
+This check flags all access to members of unions. Passing unions as a whole is not flagged.
+
+Reading from a union member assumes that member was the last one written, and writing to a union member assumes another member with a nontrivial destructor had its destructor called. This is fragile because it cannot generally be enforced to be safe in the language and so relies on programmer discipline to get it right.
+
+This rule is part of the "Type safety" profile of the C++ Core Guidelines, see
+https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#-type7-avoid-accessing-members-of-raw-unions-prefer-variant-instead
Index: clang-tools-extra/trunk/test/clang-tidy/cppcoreguidelines-pro-type-union-access.cpp
===================================================================
--- clang-tools-extra/trunk/test/clang-tidy/cppcoreguidelines-pro-type-union-access.cpp
+++ clang-tools-extra/trunk/test/clang-tidy/cppcoreguidelines-pro-type-union-access.cpp
@@ -0,0 +1,41 @@
+// RUN: %python %S/check_clang_tidy.py %s cppcoreguidelines-pro-type-union-access %t
+
+union U {
+ bool union_member1;
+ char union_member2;
+} u;
+
+struct S {
+ int non_union_member;
+ union {
+ bool union_member;
+ };
+ union {
+ char union_member2;
+ } u;
+} s;
+
+
+void f(char);
+void f2(U);
+void f3(U&);
+void f4(U*);
+
+void check()
+{
+ u.union_member1 = true;
+ // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: do not access members of unions; use (boost::)variant instead [cppcoreguidelines-pro-type-union-access]
+ auto b = u.union_member2;
+ // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: do not access members of unions; use (boost::)variant instead
+ auto a = &s.union_member;
+ // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: do not access members of unions; use (boost::)variant instead
+ f(s.u.union_member2);
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: do not access members of unions; use (boost::)variant instead
+
+ s.non_union_member = 2; // OK
+
+ U u2 = u; // OK
+ f2(u); // OK
+ f3(u); // OK
+ f4(&u); // OK
+}
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