balazske updated this revision to Diff 222161.
balazske added a comment.
- Rename to DefaultOperatorNewAlignmentCheck.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D67545/new/
https://reviews.llvm.org/D67545
Files:
clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp
clang-tools-extra/clang-tidy/cert/CMakeLists.txt
clang-tools-extra/clang-tidy/cert/DefaultOperatorNewAlignmentCheck.cpp
clang-tools-extra/clang-tidy/cert/DefaultOperatorNewAlignmentCheck.h
clang-tools-extra/docs/ReleaseNotes.rst
clang-tools-extra/docs/clang-tidy/checks/cert-mem57-cpp.rst
clang-tools-extra/docs/clang-tidy/checks/list.rst
clang-tools-extra/test/clang-tidy/cert-mem57-cpp.cpp
Index: clang-tools-extra/test/clang-tidy/cert-mem57-cpp.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/cert-mem57-cpp.cpp
@@ -0,0 +1,39 @@
+// RUN: %check_clang_tidy %s -std=c++17 cert-mem57-cpp %t
+
+namespace std {
+typedef __typeof(sizeof(int)) size_t;
+void *aligned_alloc(size_t, size_t);
+void free(void *);
+} // namespace std
+
+struct alignas(32) Vector1 {
+ char elems[32];
+};
+
+struct Vector2 {
+ char elems[32];
+};
+
+struct alignas(32) Vector3 {
+ char elems[32];
+ static void *operator new(std::size_t nbytes) noexcept(true) {
+ return std::aligned_alloc(alignof(Vector3), nbytes);
+ }
+ static void operator delete(void *p) {
+ std::free(p);
+ }
+};
+
+struct alignas(8) Vector4 {
+ char elems[32];
+};
+
+void f() {
+ auto *V1 = new Vector1;
+ // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: allocation function returns a pointer with alignment 16 but the over-aligned type being allocated requires alignment 32 [cert-mem57-cpp]
+ auto *V2 = new Vector2;
+ auto *V3 = new Vector3;
+ auto *V4 = new Vector4;
+ auto *V1_Arr = new Vector1[2];
+ // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: allocation function returns a pointer with alignment 16 but the over-aligned type being allocated requires alignment 32 [cert-mem57-cpp]
+}
Index: clang-tools-extra/docs/clang-tidy/checks/list.rst
===================================================================
--- clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -98,6 +98,7 @@
cert-err61-cpp (redirects to misc-throw-by-value-catch-by-reference) <cert-err61-cpp>
cert-fio38-c (redirects to misc-non-copyable-objects) <cert-fio38-c>
cert-flp30-c
+ cert-mem57-cpp
cert-msc30-c (redirects to cert-msc50-cpp) <cert-msc30-c>
cert-msc32-c (redirects to cert-msc51-cpp) <cert-msc32-c>
cert-msc50-cpp
Index: clang-tools-extra/docs/clang-tidy/checks/cert-mem57-cpp.rst
===================================================================
--- /dev/null
+++ clang-tools-extra/docs/clang-tidy/checks/cert-mem57-cpp.rst
@@ -0,0 +1,16 @@
+.. title:: clang-tidy - cert-mem57-cpp
+
+cert-mem57-cpp
+==============
+
+This check flags uses of default ``operator new`` where the type has extended
+alignment (an alignment greater than the fundamental alignment). (The default
+``operator new`` is guaranteed to provide the correct alignmment if the
+requested alignment is less or equal to the fundamental alignment).
+Only cases are detected (by design) where the ``operator new`` is not
+user-defined and is not a placement new (the reason is that in these cases we
+assume that the user provided the correct memory allocation).
+
+This check corresponds to the CERT C++ Coding Standard rule
+`MEM57-CPP. Avoid using default operator new for over-aligned types
+<https://wiki.sei.cmu.edu/confluence/display/cplusplus/MEM57-CPP.+Avoid+using+default+operator+new+for+over-aligned+types>`_.
Index: clang-tools-extra/docs/ReleaseNotes.rst
===================================================================
--- clang-tools-extra/docs/ReleaseNotes.rst
+++ clang-tools-extra/docs/ReleaseNotes.rst
@@ -73,6 +73,12 @@
Finds instances where variables with static storage are initialized
dynamically in header files.
+- New :doc:`cert-mem57-cpp
+ <clang-tidy/checks/cert-mem57-cpp>` check.
+
+ Checks if an object of type with extended alignment is allocated by using
+ the default ``operator new``.
+
- New :doc:`linuxkernel-must-use-errs
<clang-tidy/checks/linuxkernel-must-use-errs>` check.
Index: clang-tools-extra/clang-tidy/cert/DefaultOperatorNewAlignmentCheck.h
===================================================================
--- /dev/null
+++ clang-tools-extra/clang-tidy/cert/DefaultOperatorNewAlignmentCheck.h
@@ -0,0 +1,35 @@
+//===--- DefaultOperatorNewCheck.h - clang-tidy -----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_DEFAULTOPERATORNEWALIGNMENTCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_DEFAULTOPERATORNEWALIGNMENTCHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang {
+namespace tidy {
+namespace cert {
+
+/// Checks if an object of type with extended alignment is allocated by using
+/// the default operator new.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/cert-mem57-cpp.html
+class DefaultOperatorNewAlignmentCheck : public ClangTidyCheck {
+public:
+ DefaultOperatorNewAlignmentCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace cert
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_DEFAULTOPERATORNEWALIGNMENTCHECK_H
Index: clang-tools-extra/clang-tidy/cert/DefaultOperatorNewAlignmentCheck.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/clang-tidy/cert/DefaultOperatorNewAlignmentCheck.cpp
@@ -0,0 +1,69 @@
+//===--- DefaultOperatorNewCheck.cpp - clang-tidy --------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "DefaultOperatorNewAlignmentCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace cert {
+
+void DefaultOperatorNewAlignmentCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(cxxNewExpr().bind("new"), this);
+}
+
+void DefaultOperatorNewAlignmentCheck::check(
+ const MatchFinder::MatchResult &Result) {
+ // Get the found 'new' expression.
+ const auto *NewExpr = Result.Nodes.getNodeAs<CXXNewExpr>("new");
+
+ // Skip placement new: This is a user-defined allocation.
+ if (NewExpr->getNumPlacementArgs() > 0)
+ return;
+ QualType T = NewExpr->getAllocatedType();
+ // Dependent types do not have fixed alignment.
+ if (T->isDependentType())
+ return;
+ const TagDecl *D = T->getAsTagDecl();
+ // Alignment can not be obtained for undefined type.
+ if (!D || !D->getDefinition() || !D->isCompleteDefinition())
+ return;
+
+ ASTContext &Context = D->getASTContext();
+
+ // Check if no alignment was specified for the type.
+ if (!Context.isAlignmentRequired(T))
+ return;
+
+ // The user-specified alignment (in bits).
+ const unsigned SpecifiedAlignment = D->getMaxAlignment();
+ // Double-check if no alignment was specified.
+ if (!SpecifiedAlignment)
+ return;
+ // The alignment used by default 'operator new' (in bits).
+ const unsigned DefaultNewAlignment = Context.getTargetInfo().getNewAlign();
+
+ const bool OverAligned = SpecifiedAlignment > DefaultNewAlignment;
+ const bool HasDefaultOperatorNew =
+ !NewExpr->getOperatorNew() || NewExpr->getOperatorNew()->isImplicit();
+
+ const unsigned CharWidth = Context.getTargetInfo().getCharWidth();
+ if (HasDefaultOperatorNew && OverAligned /*&& !NewExpr->passAlignment()*/)
+ diag(NewExpr->getBeginLoc(),
+ "allocation function returns a pointer with alignment %0 but the "
+ "over-aligned type being allocated requires alignment %1")
+ << (DefaultNewAlignment / CharWidth)
+ << (SpecifiedAlignment / CharWidth);
+}
+
+} // namespace cert
+} // namespace tidy
+} // namespace clang
Index: clang-tools-extra/clang-tidy/cert/CMakeLists.txt
===================================================================
--- clang-tools-extra/clang-tidy/cert/CMakeLists.txt
+++ clang-tools-extra/clang-tidy/cert/CMakeLists.txt
@@ -3,6 +3,7 @@
add_clang_library(clangTidyCERTModule
CERTTidyModule.cpp
CommandProcessorCheck.cpp
+ DefaultOperatorNewAlignmentCheck.cpp
DontModifyStdNamespaceCheck.cpp
FloatLoopCounter.cpp
LimitedRandomnessCheck.cpp
Index: clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp
===================================================================
--- clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp
+++ clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp
@@ -18,6 +18,7 @@
#include "../performance/MoveConstructorInitCheck.h"
#include "../readability/UppercaseLiteralSuffixCheck.h"
#include "CommandProcessorCheck.h"
+#include "DefaultOperatorNewAlignmentCheck.h"
#include "DontModifyStdNamespaceCheck.h"
#include "FloatLoopCounter.h"
#include "LimitedRandomnessCheck.h"
@@ -64,6 +65,9 @@
CheckFactories.registerCheck<LimitedRandomnessCheck>("cert-msc50-cpp");
CheckFactories.registerCheck<ProperlySeededRandomGeneratorCheck>(
"cert-msc51-cpp");
+ // MEM
+ CheckFactories.registerCheck<DefaultOperatorNewAlignmentCheck>(
+ "cert-mem57-cpp");
// C checkers
// DCL
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