clang-tools-extra/clang-tidy/bugprone/UndefinedMemoryManipulationCheck.cpp

   1 //===--- UndefinedMemoryManipulationCheck.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 "UndefinedMemoryManipulationCheck.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::bugprone {
  16
  17 namespace {
  18 AST_MATCHER(CXXRecordDecl, isNotTriviallyCopyable) {
  19   // For incomplete types, assume they are TriviallyCopyable.
  20   return Node.hasDefinition() ? !Node.isTriviallyCopyable() : false;
  21 }
  22 } // namespace
  23
  24 void UndefinedMemoryManipulationCheck::registerMatchers(MatchFinder *Finder) {
  25   const auto HasNotTriviallyCopyableDecl =
  26       hasDeclaration(cxxRecordDecl(isNotTriviallyCopyable()));
  27   const auto ArrayOfNotTriviallyCopyable =
  28       arrayType(hasElementType(HasNotTriviallyCopyableDecl));
  29   const auto NotTriviallyCopyableObject = hasType(hasCanonicalType(
  30       anyOf(pointsTo(qualType(anyOf(HasNotTriviallyCopyableDecl,
  31                                     ArrayOfNotTriviallyCopyable))),
  32             ArrayOfNotTriviallyCopyable)));
  33
  34   // Check whether destination object is not TriviallyCopyable.
  35   // Applicable to all three memory manipulation functions.
  36   Finder->addMatcher(callExpr(callee(functionDecl(hasAnyName(
  37                                   "::memset", "::memcpy", "::memmove"))),
  38                               hasArgument(0, NotTriviallyCopyableObject))
  39                          .bind("dest"),
  40                      this);
  41
  42   // Check whether source object is not TriviallyCopyable.
  43   // Only applicable to memcpy() and memmove().
  44   Finder->addMatcher(
  45       callExpr(callee(functionDecl(hasAnyName("::memcpy", "::memmove"))),
  46                hasArgument(1, NotTriviallyCopyableObject))
  47           .bind("src"),
  48       this);
  49 }
  50
  51 void UndefinedMemoryManipulationCheck::check(
  52     const MatchFinder::MatchResult &Result) {
  53   if (const auto *Call = Result.Nodes.getNodeAs<CallExpr>("dest")) {
  54     QualType DestType = Call->getArg(0)->IgnoreImplicit()->getType();
  55     if (!DestType->getPointeeType().isNull())
  56       DestType = DestType->getPointeeType();
  57     diag(Call->getBeginLoc(), "undefined behavior, destination object type %0 "
  58                               "is not TriviallyCopyable")
  59         << DestType;
  60   }
  61   if (const auto *Call = Result.Nodes.getNodeAs<CallExpr>("src")) {
  62     QualType SourceType = Call->getArg(1)->IgnoreImplicit()->getType();
  63     if (!SourceType->getPointeeType().isNull())
  64       SourceType = SourceType->getPointeeType();
  65     diag(Call->getBeginLoc(),
  66          "undefined behavior, source object type %0 is not TriviallyCopyable")
  67         << SourceType;
  68   }
  69 }
  70
  71 } // namespace clang::tidy::bugprone