clang-tools-extra/clang-tidy/linuxkernel/MustCheckErrsCheck.cpp

   1 //===--- MustCheckErrsCheck.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 "MustCheckErrsCheck.h"
  10 #include "clang/AST/ASTContext.h"
  11 #include "clang/ASTMatchers/ASTMatchFinder.h"
  12
  13 using namespace clang::ast_matchers;
  14
  15 namespace clang::tidy::linuxkernel {
  16
  17 void MustCheckErrsCheck::registerMatchers(MatchFinder *Finder) {
  18   auto ErrFn =
  19       functionDecl(hasAnyName("ERR_PTR", "PTR_ERR", "IS_ERR", "IS_ERR_OR_NULL",
  20                               "ERR_CAST", "PTR_ERR_OR_ZERO"));
  21   auto NonCheckingStmts = stmt(anyOf(compoundStmt(), labelStmt()));
  22   Finder->addMatcher(
  23       callExpr(callee(ErrFn), hasParent(NonCheckingStmts)).bind("call"),
  24       this);
  25
  26   auto ReturnToCheck = returnStmt(hasReturnValue(callExpr(callee(ErrFn))));
  27   auto ReturnsErrFn = functionDecl(hasDescendant(ReturnToCheck));
  28   Finder->addMatcher(callExpr(callee(ReturnsErrFn), hasParent(NonCheckingStmts))
  29                          .bind("transitive_call"),
  30                      this);
  31 }
  32
  33 void MustCheckErrsCheck::check(const MatchFinder::MatchResult &Result) {
  34   const auto *MatchedCallExpr = Result.Nodes.getNodeAs<CallExpr>("call");
  35   if (MatchedCallExpr) {
  36     diag(MatchedCallExpr->getExprLoc(), "result from function %0 is unused")
  37         << MatchedCallExpr->getDirectCallee();
  38   }
  39
  40   const auto *MatchedTransitiveCallExpr =
  41       Result.Nodes.getNodeAs<CallExpr>("transitive_call");
  42   if (MatchedTransitiveCallExpr) {
  43     diag(MatchedTransitiveCallExpr->getExprLoc(),
  44          "result from function %0 is unused but represents an error value")
  45         << MatchedTransitiveCallExpr->getDirectCallee();
  46   }
  47 }
  48
  49 } // namespace clang::tidy::linuxkernel