[clang-tools-extra] [clang-tidy] Add bugprone-move-shared-pointer-contents check. (PR #67467)
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Thu Jan 11 12:42:52 PST 2024
https://github.com/pizzud updated https://github.com/llvm/llvm-project/pull/67467
>From 04a3e8d8cbd6943f44a81fddb0524902202a1a78 Mon Sep 17 00:00:00 2001
From: David Pizzuto <pizzud at google.com>
Date: Tue, 26 Sep 2023 10:45:42 -0700
Subject: [PATCH] [clang-tidy] Add bugprone-move-shared-pointer-contents check.
This check detects moves of the contents of a shared pointer rather than the
pointer itself. Other code with a reference to the shared pointer is probably
not expecting the move.
The set of shared pointer classes is configurable via options to allow individual
projects to cover additional types.
---
.../MoveSharedPointerContentsCheck.cpp | 157 ++++++++++++++++++
.../bugprone/MoveSharedPointerContentsCheck.h | 45 +++++
.../bugprone/move-shared-pointer-contents.rst | 19 +++
.../docs/clang-tidy/checks/list.rst | 4 +
4 files changed, 225 insertions(+)
create mode 100644 clang-tools-extra/clang-tidy/bugprone/MoveSharedPointerContentsCheck.cpp
create mode 100644 clang-tools-extra/clang-tidy/bugprone/MoveSharedPointerContentsCheck.h
create mode 100644 clang-tools-extra/docs/clang-tidy/checks/bugprone/move-shared-pointer-contents.rst
diff --git a/clang-tools-extra/clang-tidy/bugprone/MoveSharedPointerContentsCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/MoveSharedPointerContentsCheck.cpp
new file mode 100644
index 00000000000000..461fe91267e632
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/MoveSharedPointerContentsCheck.cpp
@@ -0,0 +1,157 @@
+//===--- MoveSharedPointerContentsCheck.cpp - clang-tidy ------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "MoveSharedPointerContentsCheck.h"
+#include "../ClangTidyCheck.h"
+#include "../utils/Matchers.h"
+#include "../utils/OptionsUtils.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+
+MoveSharedPointerContentsCheck::MoveSharedPointerContentsCheck(
+ StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context),
+ SharedPointerClasses(utils::options::parseStringList(
+ Options.get("SharedPointerClasses", "::std::shared_ptr"))) {}
+
+void MoveSharedPointerContentsCheck::registerMatchers(MatchFinder *Finder) {
+ auto isStdMove = callee(functionDecl(hasName("::std::move")));
+
+ // Resolved type, direct move.
+ Finder->addMatcher(
+ callExpr(isStdMove, hasArgument(0, cxxOperatorCallExpr(
+ hasOverloadedOperatorName("*"),
+ callee(cxxMethodDecl(ofClass(
+ matchers::matchesAnyListedName(
+ SharedPointerClasses)))))))
+ .bind("call"),
+ this);
+
+ // Resolved type, move out of get().
+ Finder->addMatcher(
+ callExpr(
+ isStdMove,
+ hasArgument(
+ 0, unaryOperator(
+ hasOperatorName("*"),
+ hasUnaryOperand(cxxMemberCallExpr(callee(cxxMethodDecl(
+ hasName("get"), ofClass(matchers::matchesAnyListedName(
+ SharedPointerClasses)))))))))
+ .bind("get_call"),
+ this);
+
+ auto isStdMoveUnresolved = callee(unresolvedLookupExpr(
+ hasAnyDeclaration(namedDecl(hasUnderlyingDecl(hasName("::std::move"))))));
+
+ // Unresolved type, direct move.
+ Finder->addMatcher(
+ callExpr(
+ isStdMoveUnresolved,
+ hasArgument(0, unaryOperator(hasOperatorName("*"),
+ hasUnaryOperand(declRefExpr(hasType(
+ qualType().bind("unresolved_p")))))))
+ .bind("unresolved_call"),
+ this);
+ // Annoyingly, the declRefExpr in the unresolved-move-of-get() case
+ // is of <dependent type> rather than shared_ptr<T>, so we have to
+ // just fetch the variable. This does leave a gap where a temporary
+ // shared_ptr wouldn't be caught, but moving out of a temporary
+ // shared pointer is a truly wild thing to do so it should be okay.
+
+ // Unresolved type, move out of get().
+ Finder->addMatcher(
+ callExpr(isStdMoveUnresolved,
+ hasArgument(
+ 0, unaryOperator(hasOperatorName("*"),
+ hasDescendant(cxxDependentScopeMemberExpr(
+ hasMemberName("get"))),
+ hasDescendant(declRefExpr(to(
+ varDecl().bind("unresolved_get_p")))))))
+ .bind("unresolved_get_call"),
+ this);
+}
+
+bool MoveSharedPointerContentsCheck::isSharedPointerClass(
+ const VarDecl *VD) const {
+ if (VD == nullptr)
+ return false;
+
+ const QualType QT = VD->getType();
+ return isSharedPointerClass(&QT);
+}
+
+bool MoveSharedPointerContentsCheck::isSharedPointerClass(
+ const QualType *QT) const {
+ if (QT == nullptr)
+ return false;
+
+ // We want the qualified name without template parameters,
+ // const/volatile, or reference/pointer qualifiers so we can look
+ // it up in SharedPointerClasses. This is a bit messy, but gets us
+ // to the underlying type without template parameters (eg
+ // std::shared_ptr) or const/volatile qualifiers even in the face of
+ // typedefs.
+
+ bool found = false;
+ const auto *Template = llvm::dyn_cast<TemplateSpecializationType>(
+ QT->getSplitDesugaredType().Ty);
+ if (Template != nullptr) {
+ const std::string TypeName = Template->getTemplateName()
+ .getAsTemplateDecl()
+ ->getQualifiedNameAsString();
+ for (const llvm::StringRef SharedPointer : SharedPointerClasses) {
+ // SharedPointer entries may or may not have leading ::, but TypeName
+ // definitely won't.
+ if (SharedPointer == TypeName || SharedPointer.substr(2) == TypeName) {
+ found = true;
+ break;
+ }
+ }
+ }
+
+ return found;
+}
+
+void MoveSharedPointerContentsCheck::check(
+ const MatchFinder::MatchResult &Result) {
+ const bool Unresolved =
+ isSharedPointerClass(Result.Nodes.getNodeAs<QualType>("unresolved_p"));
+ const bool UnresolvedGet =
+ isSharedPointerClass(Result.Nodes.getNodeAs<VarDecl>("unresolved_get_p"));
+
+ clang::SourceLocation Loc;
+ if (const auto *UnresolvedCall =
+ Result.Nodes.getNodeAs<CallExpr>("unresolved_call");
+ UnresolvedCall != nullptr && Unresolved) {
+ Loc = UnresolvedCall->getBeginLoc();
+ } else if (const auto *UnresolvedGetCall =
+ Result.Nodes.getNodeAs<CallExpr>("unresolved_get_call");
+ UnresolvedGetCall != nullptr && UnresolvedGet) {
+ Loc = UnresolvedGetCall->getBeginLoc();
+ } else if (const auto *GetCall = Result.Nodes.getNodeAs<CallExpr>("get_call");
+ GetCall != nullptr) {
+ Loc = GetCall->getBeginLoc();
+ } else if (const auto *Call = Result.Nodes.getNodeAs<CallExpr>("call");
+ Call != nullptr) {
+ Loc = Call->getBeginLoc();
+ } else {
+ return;
+ }
+
+ if (Loc.isValid()) {
+ diag(Loc,
+ "don't move the contents out of a shared pointer, as other accessors "
+ "expect them to remain in a determinate state");
+ }
+}
+
+} // namespace clang::tidy::bugprone
diff --git a/clang-tools-extra/clang-tidy/bugprone/MoveSharedPointerContentsCheck.h b/clang-tools-extra/clang-tidy/bugprone/MoveSharedPointerContentsCheck.h
new file mode 100644
index 00000000000000..c3a6ca83b24ec7
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/MoveSharedPointerContentsCheck.h
@@ -0,0 +1,45 @@
+//===--- MoveSharedPointerContentsCheck.h - clang-tidy ----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_MOVESHAREDPOINTERCONTENTSCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_MOVESHAREDPOINTERCONTENTSCHECK_H
+
+#include <vector>
+
+#include "../ClangTidyCheck.h"
+
+namespace clang::tidy::bugprone {
+
+/// Detects calls to move the contents out of a ``std::shared_ptr`` rather than
+/// moving the pointer itself.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/move-shared-pointer-contents.html
+class MoveSharedPointerContentsCheck : public ClangTidyCheck {
+public:
+ MoveSharedPointerContentsCheck(StringRef Name, ClangTidyContext *Context);
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+ bool
+ isLanguageVersionSupported(const LangOptions &LangOptions) const override {
+ return LangOptions.CPlusPlus11;
+ }
+ std::optional<TraversalKind> getCheckTraversalKind() const override {
+ return TK_IgnoreUnlessSpelledInSource;
+ }
+
+private:
+ // Returns whether the type or variable is one of the SharedPointerClasses.
+ bool isSharedPointerClass(const VarDecl *VD) const;
+ bool isSharedPointerClass(const QualType *QT) const;
+ const std::vector<StringRef> SharedPointerClasses;
+};
+
+} // namespace clang::tidy::bugprone
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_MOVESHAREDPOINTERCONTENTSCHECK_H
diff --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/move-shared-pointer-contents.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/move-shared-pointer-contents.rst
new file mode 100644
index 00000000000000..ea4c1fb6df708c
--- /dev/null
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/move-shared-pointer-contents.rst
@@ -0,0 +1,19 @@
+.. title:: clang-tidy - bugprone-move-shared-pointer-contents
+
+bugprone-move-shared-pointer-contents
+=====================================
+
+
+Detects calls to move the contents out of a ``std::shared_ptr`` rather
+than moving the pointer itself. In other words, calling
+``std::move(*p)`` or ``std::move(*p.get())``. Other reference holders
+may not be expecting the move and suddenly getting empty or otherwise
+indeterminate states can cause issues.
+
+Options
+-------
+.. option :: SharedPointerClasses
+
+ A semicolon-separated list of class names that should be treated as shared
+ pointers. Classes are resolved through aliases, so any alias to the defined
+ classes will be considered. Default is `::std::shared_ptr`.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index 2f86121ad87299..a2996b9f9f18fd 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -118,6 +118,10 @@ Clang-Tidy Checks
:doc:`bugprone-posix-return <bugprone/posix-return>`, "Yes"
:doc:`bugprone-redundant-branch-condition <bugprone/redundant-branch-condition>`, "Yes"
:doc:`bugprone-reserved-identifier <bugprone/reserved-identifier>`, "Yes"
+<<<<<<< HEAD
+=======
+ :doc:`bugprone-shared-pointer-contents-move <bugprone/shared-pointer-contents-move>`,
+>>>>>>> b81b29d180ac ([clang-tidy] Add bugprone-move-shared-pointer-contents check.)
:doc:`bugprone-shared-ptr-array-mismatch <bugprone/shared-ptr-array-mismatch>`, "Yes"
:doc:`bugprone-signal-handler <bugprone/signal-handler>`,
:doc:`bugprone-signed-char-misuse <bugprone/signed-char-misuse>`,
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