pfultz2 created this revision.
pfultz2 added reviewers: clang-tools-extra, aaron.ballman.
pfultz2 added a project: clang-tools-extra.
Herald added a subscriber: mgorny.
Diagnoses when a non-trivial type is not assigned to a variable. This is useful
to check for problems like unnamed lock guards.
For example, if you had code written like this:
int g_i = 0;
std::mutex g_i_mutex; // protects g_i
void safe_increment()
{
std::lock_guard<std::mutex>{g_i_mutex};
// The lock is locked and then unlocked before reaching here
++g_i;
}
This will warn that a variable should be created instead:
int g_i = 0;
std::mutex g_i_mutex; // protects g_i
void safe_increment()
{
std::lock_guard<std::mutex> lock{g_i_mutex};
// The lock is locked and then will be unlocked when exiting scope
++g_i;
}
Repository:
rCTE Clang Tools Extra
https://reviews.llvm.org/D44241
Files:
clang-tidy/misc/CMakeLists.txt
clang-tidy/misc/MiscTidyModule.cpp
clang-tidy/misc/OwnerlessResourceCheck.cpp
clang-tidy/misc/OwnerlessResourceCheck.h
docs/ReleaseNotes.rst
docs/clang-tidy/checks/list.rst
docs/clang-tidy/checks/misc-ownerless-resource.rst
test/clang-tidy/misc-ownerless-resource.cpp
Index: test/clang-tidy/misc-ownerless-resource.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/misc-ownerless-resource.cpp
@@ -0,0 +1,36 @@
+// RUN: %check_clang_tidy %s misc-ownerless-resource %t
+
+struct Trivial {};
+
+struct NonTrivial {
+ int *mem;
+ NonTrivial()
+ : mem(new int()) {}
+ NonTrivial(int)
+ : mem(new int()) {}
+ ~NonTrivial() {
+ delete mem;
+ }
+};
+
+NonTrivial f() { return {}; }
+void g(NonTrivial) {}
+
+void fail() {
+ NonTrivial{};
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: Resource has no owner; Did you mean to declare it with a variable name? [misc-ownerless-resource]
+ NonTrivial{1};
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: Resource has no owner; Did you mean to declare it with a variable name? [misc-ownerless-resource]
+}
+
+void valid() {
+ NonTrivial a{};
+ auto b = NonTrivial{};
+
+ g(f());
+ f();
+
+ auto c = f();
+ Trivial{};
+ Trivial x{};
+}
Index: docs/clang-tidy/checks/misc-ownerless-resource.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/misc-ownerless-resource.rst
@@ -0,0 +1,34 @@
+.. title:: clang-tidy - misc-ownerless-resource
+
+misc-ownerless-resource
+=======================
+
+Diagnoses when a non-trivial type is not assigned to a variable. This is useful to check for problems like unamed lock guards.
+
+For example, if you had code written like this:
+
+.. code-block:: c++
+
+ int g_i = 0;
+ std::mutex g_i_mutex; // protects g_i
+
+ void safe_increment()
+ {
+ std::lock_guard<std::mutex>{g_i_mutex};
+ // The lock is locked and then unlocked before reaching here
+ ++g_i;
+ }
+
+This will warn that a variable should be created instead:
+
+.. code-block:: c++
+
+ int g_i = 0;
+ std::mutex g_i_mutex; // protects g_i
+
+ void safe_increment()
+ {
+ std::lock_guard<std::mutex> lock{g_i_mutex};
+ // The lock is locked and then will be unlocked when exiting scope
+ ++g_i;
+ }
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -143,6 +143,7 @@
misc-misplaced-const
misc-new-delete-overloads
misc-non-copyable-objects
+ misc-ownerless-resource
misc-redundant-expression
misc-sizeof-container
misc-sizeof-expression
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -57,6 +57,12 @@
Improvements to clang-tidy
--------------------------
+- New `misc-ownerless-resource
+ <http://clang.llvm.org/extra/clang-tidy/checks/misc-ownerless-resource.html>`_ check
+
+ Diagnoses when a non-trivial type is not assigned to a variable. This is
+ useful to check for problems like unamed lock guards.
+
- New `bugprone-throw-keyword-missing
<http://clang.llvm.org/extra/clang-tidy/checks/bugprone-throw-keyword-missing.html>`_ check
Index: clang-tidy/misc/OwnerlessResourceCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/misc/OwnerlessResourceCheck.h
@@ -0,0 +1,35 @@
+//===--- OwnerlessResourceCheck.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_MISC_OWNERLESSRESOURCECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_OWNERLESSRESOURCECHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+/// Diagnoses when a non-trivial type is not assigned to a variable.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/misc-ownerless-resource.html
+class OwnerlessResourceCheck : public ClangTidyCheck {
+public:
+ OwnerlessResourceCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_OWNERLESSRESOURCECHECK_H
Index: clang-tidy/misc/OwnerlessResourceCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/misc/OwnerlessResourceCheck.cpp
@@ -0,0 +1,37 @@
+//===--- OwnerlessResourceCheck.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 "OwnerlessResourceCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+void OwnerlessResourceCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(
+ exprWithCleanups(unless(hasType(voidType())),
+ has(cxxBindTemporaryExpr(has(cxxTemporaryObjectExpr()))))
+ .bind("ownerless-resource"),
+ this);
+}
+
+void OwnerlessResourceCheck::check(const MatchFinder::MatchResult &Result) {
+ if (const auto *E = Result.Nodes.getNodeAs<Expr>("ownerless-resource")) {
+ diag(E->getLocStart(), "Resource has no owner; Did you mean to declare it "
+ "with a variable name?");
+ }
+}
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/misc/MiscTidyModule.cpp
===================================================================
--- clang-tidy/misc/MiscTidyModule.cpp
+++ clang-tidy/misc/MiscTidyModule.cpp
@@ -15,6 +15,7 @@
#include "MisplacedConstCheck.h"
#include "NewDeleteOverloadsCheck.h"
#include "NonCopyableObjects.h"
+#include "OwnerlessResourceCheck.h"
#include "RedundantExpressionCheck.h"
#include "SizeofContainerCheck.h"
#include "SizeofExpressionCheck.h"
@@ -35,6 +36,8 @@
public:
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
CheckFactories.registerCheck<MisplacedConstCheck>("misc-misplaced-const");
+ CheckFactories.registerCheck<OwnerlessResourceCheck>(
+ "misc-ownerless-resource");
CheckFactories.registerCheck<UnconventionalAssignOperatorCheck>(
"misc-unconventional-assign-operator");
CheckFactories.registerCheck<DefinitionsInHeadersCheck>(
Index: clang-tidy/misc/CMakeLists.txt
===================================================================
--- clang-tidy/misc/CMakeLists.txt
+++ clang-tidy/misc/CMakeLists.txt
@@ -2,6 +2,7 @@
add_clang_library(clangTidyMiscModule
MisplacedConstCheck.cpp
+ OwnerlessResourceCheck.cpp
UnconventionalAssignOperatorCheck.cpp
DefinitionsInHeadersCheck.cpp
MacroParenthesesCheck.cpp
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