clang-tools-extra/clang-tidy/misc/CoroutineHostileRAIICheck.cpp

   1 //===--- CoroutineHostileRAII.cpp - clang-tidy ----------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "CoroutineHostileRAIICheck.h"
  10 #include "../utils/OptionsUtils.h"
  11 #include "clang/AST/Attr.h"
  12 #include "clang/AST/Decl.h"
  13 #include "clang/AST/ExprCXX.h"
  14 #include "clang/AST/Stmt.h"
  15 #include "clang/AST/Type.h"
  16 #include "clang/ASTMatchers/ASTMatchFinder.h"
  17 #include "clang/ASTMatchers/ASTMatchers.h"
  18 #include "clang/ASTMatchers/ASTMatchersInternal.h"
  19 #include "clang/Basic/AttrKinds.h"
  20 #include "clang/Basic/DiagnosticIDs.h"
  21
  22 using namespace clang::ast_matchers;
  23 namespace clang::tidy::misc {
  24 namespace {
  25 using clang::ast_matchers::internal::BoundNodesTreeBuilder;
  26
  27 AST_MATCHER_P(Stmt, forEachPrevStmt, ast_matchers::internal::Matcher<Stmt>,
  28               InnerMatcher) {
  29   DynTypedNode P;
  30   bool IsHostile = false;
  31   for (const Stmt *Child = &Node; Child; Child = P.get<Stmt>()) {
  32     auto Parents = Finder->getASTContext().getParents(*Child);
  33     if (Parents.empty())
  34       break;
  35     P = *Parents.begin();
  36     auto *PCS = P.get<CompoundStmt>();
  37     if (!PCS)
  38       continue;
  39     for (const auto &Sibling : PCS->children()) {
  40       // Child contains suspension. Siblings after Child do not persist across
  41       // this suspension.
  42       if (Sibling == Child)
  43         break;
  44       // In case of a match, add the bindings as a separate match. Also don't
  45       // clear the bindings if a match is not found (unlike Matcher::matches).
  46       BoundNodesTreeBuilder SiblingBuilder;
  47       if (InnerMatcher.matches(*Sibling, Finder, &SiblingBuilder)) {
  48         Builder->addMatch(SiblingBuilder);
  49         IsHostile = true;
  50       }
  51     }
  52   }
  53   return IsHostile;
  54 }
  55
  56 // Matches the expression awaited by the `co_await`.
  57 AST_MATCHER_P(CoawaitExpr, awaitable, ast_matchers::internal::Matcher<Expr>,
  58               InnerMatcher) {
  59   if (Expr *E = Node.getOperand())
  60     return InnerMatcher.matches(*E, Finder, Builder);
  61   return false;
  62 }
  63
  64 auto typeWithNameIn(const std::vector<StringRef> &Names) {
  65   return hasType(
  66       hasCanonicalType(hasDeclaration(namedDecl(hasAnyName(Names)))));
  67 }
  68 } // namespace
  69
  70 CoroutineHostileRAIICheck::CoroutineHostileRAIICheck(StringRef Name,
  71                                                      ClangTidyContext *Context)
  72     : ClangTidyCheck(Name, Context),
  73       RAIITypesList(utils::options::parseStringList(
  74           Options.get("RAIITypesList", "std::lock_guard;std::scoped_lock"))),
  75       AllowedAwaitablesList(utils::options::parseStringList(
  76           Options.get("AllowedAwaitablesList", ""))) {}
  77
  78 void CoroutineHostileRAIICheck::registerMatchers(MatchFinder *Finder) {
  79   // A suspension happens with co_await or co_yield.
  80   auto ScopedLockable = varDecl(hasType(hasCanonicalType(hasDeclaration(
  81                                     hasAttr(attr::Kind::ScopedLockable)))))
  82                             .bind("scoped-lockable");
  83   auto OtherRAII = varDecl(typeWithNameIn(RAIITypesList)).bind("raii");
  84   auto AllowedSuspend = awaitable(typeWithNameIn(AllowedAwaitablesList));
  85   Finder->addMatcher(
  86       expr(anyOf(coawaitExpr(unless(AllowedSuspend)), coyieldExpr()),
  87            forEachPrevStmt(
  88                declStmt(forEach(varDecl(anyOf(ScopedLockable, OtherRAII))))))
  89           .bind("suspension"),
  90       this);
  91 }
  92
  93 void CoroutineHostileRAIICheck::check(const MatchFinder::MatchResult &Result) {
  94   if (const auto *VD = Result.Nodes.getNodeAs<VarDecl>("scoped-lockable"))
  95     diag(VD->getLocation(),
  96          "%0 holds a lock across a suspension point of coroutine and could be "
  97          "unlocked by a different thread")
  98         << VD;
  99   if (const auto *VD = Result.Nodes.getNodeAs<VarDecl>("raii"))
 100     diag(VD->getLocation(),
 101          "%0 persists across a suspension point of coroutine")
 102         << VD;
 103   if (const auto *Suspension = Result.Nodes.getNodeAs<Expr>("suspension"))
 104     diag(Suspension->getBeginLoc(), "suspension point is here",
 105          DiagnosticIDs::Note);
 106 }
 107
 108 void CoroutineHostileRAIICheck::storeOptions(
 109     ClangTidyOptions::OptionMap &Opts) {
 110   Options.store(Opts, "RAIITypesList",
 111                 utils::options::serializeStringList(RAIITypesList));
 112   Options.store(Opts, "SafeAwaitableList",
 113                 utils::options::serializeStringList(AllowedAwaitablesList));
 114 }
 115 } // namespace clang::tidy::misc