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