[clang-tools-extra] [clang-tidy] Add bugprone-move-shared-pointer-contents check. (PR #67467)

[Baranov Victor via cfe-commits]

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@@ -0,0 +1,137 @@
+//===--- 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 {
+namespace {
+
+// Reports whether the QualType matches the inner matcher, which is expected to
+// be matchesAnyListedName. The QualType is expected to either point to a
+// RecordDecl (for concrete types) or an ElaboratedType (for dependent ones).
+AST_MATCHER_P(QualType, isSharedPointer,
+              clang::ast_matchers::internal::Matcher<NamedDecl>, InnerMatcher) {
+  if (const auto *RD = Node.getTypePtr()->getAsCXXRecordDecl(); RD != nullptr) {
+    return InnerMatcher.matches(*RD, Finder, Builder);
+  } else if (const auto *ED = Node.getTypePtr()->getAs<ElaboratedType>();
+             ED != nullptr) {
+    if (const auto *TS = ED->getNamedType()
+                             .getTypePtr()
+                             ->getAs<TemplateSpecializationType>();
+        TS != nullptr) {
+      return InnerMatcher.matches(*TS->getTemplateName().getAsTemplateDecl(),
+                                  Finder, Builder);
+    }
+  }
+
+  return false;
+}
+
+} // namespace
+
+MoveSharedPointerContentsCheck::MoveSharedPointerContentsCheck(
+    StringRef Name, ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      SharedPointerClasses(utils::options::parseStringList(
+          Options.get("SharedPointerClasses",
+                      "::std::shared_ptr;::boost::shared_pointer"))) {}
+
+void MoveSharedPointerContentsCheck::registerMatchers(MatchFinder *Finder) {
+  auto isStdMove =
+      callee(functionDecl(hasAnyName("::std::move", "::std::forward")));
+
+  auto resolvedType = callExpr(anyOf(
+      // Resolved type, direct move.
+      callExpr(isStdMove,
+               hasArgument(
+                   0, cxxOperatorCallExpr(
+                          hasOverloadedOperatorName("*"),
+                          hasArgument(
+                              0, declRefExpr(hasType(qualType(isSharedPointer(
+                                     matchers::matchesAnyListedName(
+                                         SharedPointerClasses)))))),
+                          callee(cxxMethodDecl()))))
+          .bind("call"),
+      // Resolved type, move out of get().
+      callExpr(
+          isStdMove,
+          hasArgument(
+              0, unaryOperator(
+                     hasOperatorName("*"),
+                     hasUnaryOperand(allOf(
+                         hasDescendant(declRefExpr(hasType(qualType(
+                             isSharedPointer(matchers::matchesAnyListedName(
+                                 SharedPointerClasses)))))),
+                         cxxMemberCallExpr(
+                             callee(cxxMethodDecl(hasName("get")))))))))
+          .bind("get_call")));
+
+  Finder->addMatcher(resolvedType, this);
+
+  auto isStdMoveUnresolved = callee(unresolvedLookupExpr(
+      hasAnyDeclaration(namedDecl(hasUnderlyingDecl(hasName("::std::move"))))));
+
+  auto unresolvedType = callExpr(anyOf(
+      // Unresolved type, direct move.
+      callExpr(
+          isStdMoveUnresolved,
+          hasArgument(0, unaryOperator(
+                             hasOperatorName("*"),
+                             hasUnaryOperand(declRefExpr(hasType(qualType(
+                                 isSharedPointer(matchers::matchesAnyListedName(
+                                     SharedPointerClasses)))))))))
+          .bind("unresolved_call"),
+
+      // 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.
+      callExpr(isStdMoveUnresolved,
+               hasArgument(
+                   0, unaryOperator(
+                          hasOperatorName("*"),
+                          hasDescendant(cxxDependentScopeMemberExpr(
+                              hasMemberName("get"))),
+                          hasDescendant(declRefExpr(to(varDecl(hasType(qualType(
+                              isSharedPointer(matchers::matchesAnyListedName(
+                                  SharedPointerClasses)))))))))))
+          .bind("unresolved_get_call")));
+
+  Finder->addMatcher(unresolvedType, this);
+}
+
+void MoveSharedPointerContentsCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  const CallExpr *Call = nullptr;
+  for (const llvm::StringRef binding :
+       {"unresolved_call", "unresolved_get_call", "get_call", "call"}) {
+    if (const auto *C = Result.Nodes.getNodeAs<CallExpr>(binding);
+        C != nullptr) {
+      Call = C;
+      break;
+    }
+  }
+
+  if (Call == nullptr && !Call->getBeginLoc().isValid()) {
----------------
vbvictor wrote:

Should this be `Call != nullptr` or simply `Call &&`

https://github.com/llvm/llvm-project/pull/67467