[clang-tools-extra] [clang-tidy] Add check to diagnose coroutine-hostile RAII objects (PR #68738)

[Piotr Zegar via cfe-commits]

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@@ -0,0 +1,117 @@
+//===--- CoroutineHostileRAII.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 "CoroutineHostileRAIICheck.h"
+#include "../utils/OptionsUtils.h"
+#include "clang/AST/Attr.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/Stmt.h"
+#include "clang/AST/Type.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/ASTMatchers/ASTMatchersInternal.h"
+#include "clang/Basic/AttrKinds.h"
+#include "clang/Basic/DiagnosticIDs.h"
+
+using namespace clang::ast_matchers;
+namespace clang::tidy::misc {
+using ::clang::ast_matchers::internal::ASTMatchFinder;
+using clang::ast_matchers::internal::BoundNodesTreeBuilder;
+
+// In case of a match, add the bindings as a separate match. Also don't clear
+// the bindings if a match is not found (unlike Matcher::matches).
+template <class Matcher, class Node>
+bool match(Matcher M, Node &N, ASTMatchFinder *Finder,
+           BoundNodesTreeBuilder *Builder) {
+  BoundNodesTreeBuilder LocalBuilder;
+  if (M.matches(N, Finder, &LocalBuilder)) {
+    Builder->addMatch(LocalBuilder);
+    return true;
+  }
+  return false;
+}
+
+CoroutineHostileRAIICheck::CoroutineHostileRAIICheck(StringRef Name,
+                                                     ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      RAIITypesList(utils::options::parseStringList(
+          Options.get("RAIITypesList", "std::lock_guard;std::scoped_lock"))) {}
+
+AST_MATCHER_P(VarDecl, isHostileRAII, std::vector<StringRef>, RAIITypesList) {
+  return match(varDecl(hasType(hasCanonicalType(hasDeclaration(
+                           hasAttr(attr::Kind::ScopedLockable)))))
+                   .bind("scoped-lockable"),
+               Node, Finder, Builder) ||
+         match(varDecl(hasType(hasCanonicalType(hasDeclaration(
+                           namedDecl(hasAnyName(RAIITypesList))))))
+                   .bind("raii"),
+               Node, Finder, Builder);
+}
+
+AST_MATCHER_P(DeclStmt, hasHostileRAII, std::vector<StringRef>, RAIITypesList) {
+  bool IsHostile = false;
+  for (Decl *D : Node.decls())
+    IsHostile |=
+        match(varDecl(isHostileRAII(RAIITypesList)), *D, Finder, Builder);
+  return IsHostile;
+}
+
+AST_MATCHER_P(Expr, isHostileSuspension, std::vector<StringRef>,
+              RAIITypesList) {
+  DynTypedNode P;
+  bool IsHostile = false;
+  for (const Stmt *Child = &Node; Child; Child = P.get<Stmt>()) {
+    auto Parents = Finder->getASTContext().getParents(*Child);
+    if (Parents.empty())
+      break;
+    P = *Parents.begin();
+    auto *PCS = P.get<CompoundStmt>();
+    if (!PCS)
+      continue;
+    for (const auto &Sibling : PCS->children()) {
+      // Child contains suspension. Siblings after Child do not persist across
+      // this suspension.
+      if (Sibling == Child)
+        break;
+      IsHostile |= match(declStmt(hasHostileRAII(RAIITypesList)), *Sibling,
+                         Finder, Builder);
+    }
+  }
+  return IsHostile;
+}
+
+void CoroutineHostileRAIICheck::registerMatchers(MatchFinder *Finder) {
+  // A suspension happens with co_await or co_yield.
+  Finder->addMatcher(
----------------
PiotrZSL wrote:

those 2 can be merged:
```
Finder->addMatcher(expr(anyOf(coawaitExpr(), coyieldExpr()),  
isHostileSuspension(RAIITypesList)).bind("suspension"), this);.
```
Unfortunately we do not have a matcher for an CoroutineSuspendExpr, probably could be added.

https://github.com/llvm/llvm-project/pull/68738