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
AST_MATCHER_P(Stmt,forEachPrevStmt,ast_matchers::internal::Matcher<Stmt>,InnerMatcher)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`.
AST_MATCHER_P(CoawaitExpr,awaitable,ast_matchers::internal::Matcher<Expr>,InnerMatcher)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
typeWithNameIn(const std::vector<StringRef> & Names)64 auto typeWithNameIn(const std::vector<StringRef> &Names) {
65 return hasType(
66 hasCanonicalType(hasDeclaration(namedDecl(hasAnyName(Names)))));
67 }
68 } // namespace
69
CoroutineHostileRAIICheck(StringRef Name,ClangTidyContext * Context)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
registerMatchers(MatchFinder * Finder)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
check(const MatchFinder::MatchResult & Result)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
storeOptions(ClangTidyOptions::OptionMap & Opts)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
116