1 /* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
4
5 #include "MustUseChecker.h"
6 #include "CustomMatchers.h"
7 #include "CustomTypeAnnotation.h"
8
9 CustomTypeAnnotation MustUse =
10 CustomTypeAnnotation(moz_must_use_type, "must-use");
11
registerMatchers(MatchFinder * AstMatcher)12 void MustUseChecker::registerMatchers(MatchFinder *AstMatcher) {
13 AstMatcher->addMatcher(switchCase().bind("switchcase"), this);
14 AstMatcher->addMatcher(compoundStmt().bind("compound"), this);
15 AstMatcher->addMatcher(ifStmt().bind("if"), this);
16 AstMatcher->addMatcher(whileStmt().bind("while"), this);
17 AstMatcher->addMatcher(doStmt().bind("do"), this);
18 AstMatcher->addMatcher(forStmt().bind("for"), this);
19 AstMatcher->addMatcher(binaryOperator(binaryCommaOperator()).bind("bin"),
20 this);
21 }
22
check(const MatchFinder::MatchResult & Result)23 void MustUseChecker::check(const MatchFinder::MatchResult &Result) {
24 if (auto SC = Result.Nodes.getNodeAs<SwitchCase>("switchcase")) {
25 handleUnusedExprResult(SC->getSubStmt());
26 }
27 if (auto C = Result.Nodes.getNodeAs<CompoundStmt>("compound")) {
28 for (const auto &S : C->body()) {
29 handleUnusedExprResult(S);
30 }
31 }
32 if (auto IF = Result.Nodes.getNodeAs<IfStmt>("if")) {
33 handleUnusedExprResult(IF->getThen());
34 handleUnusedExprResult(IF->getElse());
35 }
36 if (auto W = Result.Nodes.getNodeAs<WhileStmt>("while")) {
37 handleUnusedExprResult(W->getBody());
38 }
39 if (auto D = Result.Nodes.getNodeAs<DoStmt>("do")) {
40 handleUnusedExprResult(D->getBody());
41 }
42 if (auto F = Result.Nodes.getNodeAs<ForStmt>("for")) {
43 handleUnusedExprResult(F->getBody());
44 handleUnusedExprResult(F->getInit());
45 handleUnusedExprResult(F->getInc());
46 }
47 if (auto C = Result.Nodes.getNodeAs<BinaryOperator>("bin")) {
48 handleUnusedExprResult(C->getLHS());
49 }
50 }
51
handleUnusedExprResult(const Stmt * Statement)52 void MustUseChecker::handleUnusedExprResult(const Stmt *Statement) {
53 const Expr *E = dyn_cast_or_null<Expr>(Statement);
54 if (E) {
55 E = E->IgnoreImplicit(); // Ignore ExprWithCleanup etc. implicit wrappers
56 QualType T = E->getType();
57 if (MustUse.hasEffectiveAnnotation(T) && !isIgnoredExprForMustUse(E)) {
58 diag(E->getBeginLoc(), "Unused value of must-use type %0",
59 DiagnosticIDs::Error)
60 << T;
61 MustUse.dumpAnnotationReason(*this, T, E->getBeginLoc());
62 }
63 }
64 }
65