https://github.com/adrian-prantl updated
https://github.com/llvm/llvm-project/pull/69465
>From 627f68e57b2526fb72285ef4831fc3c02a6ee6d0 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0...@163.com>
Date: Wed, 18 Oct 2023 08:47:02 +0800
Subject: [PATCH 1/6] [clang-tidy]Add new check bugprone-casting-through-void
Fixes: #68532
---
.../bugprone/BugproneTidyModule.cpp | 3 ++
.../clang-tidy/bugprone/CMakeLists.txt | 1 +
.../bugprone/CastingThroughVoidCheck.cpp | 46 +++++++++++++++++++
.../bugprone/CastingThroughVoidCheck.h | 37 +++++++++++++++
clang-tools-extra/docs/ReleaseNotes.rst | 6 +++
.../checks/bugprone/casting-through-void.rst | 11 +++++
.../docs/clang-tidy/checks/list.rst | 1 +
.../bugprone/casting-through-void.cpp | 18 ++++++++
8 files changed, 123 insertions(+)
create mode 100644
clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
create mode 100644
clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
create mode 100644
clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
create mode 100644
clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
diff --git a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
index 543c522899d7a52..7a910037368c832 100644
--- a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
@@ -16,6 +16,7 @@
#include "BadSignalToKillThreadCheck.h"
#include "BoolPointerImplicitConversionCheck.h"
#include "BranchCloneCheck.h"
+#include "CastingThroughVoidCheck.h"
#include "ComparePointerToMemberVirtualFunctionCheck.h"
#include "CopyConstructorInitCheck.h"
#include "DanglingHandleCheck.h"
@@ -104,6 +105,8 @@ class BugproneModule : public ClangTidyModule {
CheckFactories.registerCheck<BoolPointerImplicitConversionCheck>(
"bugprone-bool-pointer-implicit-conversion");
CheckFactories.registerCheck<BranchCloneCheck>("bugprone-branch-clone");
+ CheckFactories.registerCheck<CastingThroughVoidCheck>(
+ "bugprone-casting-through-void");
CheckFactories.registerCheck<ComparePointerToMemberVirtualFunctionCheck>(
"bugprone-compare-pointer-to-member-virtual-function");
CheckFactories.registerCheck<CopyConstructorInitCheck>(
diff --git a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
index 0df9e439b715e5a..d443fd8d1452f16 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
@@ -11,6 +11,7 @@ add_clang_library(clangTidyBugproneModule
BoolPointerImplicitConversionCheck.cpp
BranchCloneCheck.cpp
BugproneTidyModule.cpp
+ CastingThroughVoidCheck.cpp
ComparePointerToMemberVirtualFunctionCheck.cpp
CopyConstructorInitCheck.cpp
DanglingHandleCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
new file mode 100644
index 000000000000000..7b9cd7dd51fc47f
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
@@ -0,0 +1,46 @@
+//===--- CastingThroughVoidCheck.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 "CastingThroughVoidCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/Type.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "llvm/ADT/StringSet.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+
+void CastingThroughVoidCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(
+ explicitCastExpr(
+ hasDestinationType(qualType(pointsTo(qualType(unless(voidType()))))
+ .bind("target_type")),
+ hasSourceExpression(
+ explicitCastExpr(hasSourceExpression(expr(
+ hasType(qualType().bind("source_type")))),
+ hasDestinationType(pointsTo(voidType())))))
+ .bind("cast"),
+ this);
+}
+
+void CastingThroughVoidCheck::check(const MatchFinder::MatchResult &Result) {
+ ASTContext *Context = Result.Context;
+ const auto *CE = Result.Nodes.getNodeAs<ExplicitCastExpr>("cast");
+ const auto *TT = Result.Nodes.getNodeAs<QualType>("target_type");
+ const auto *ST = Result.Nodes.getNodeAs<QualType>("source_type");
+ if (Context->hasSameType(*TT, *ST))
+ return;
+ diag(CE->getSourceRange().getBegin(), "do not cast %0 to %1 through void *",
+ DiagnosticIDs::Level::Warning)
+ << ST->getAsString() << TT->getAsString();
+}
+
+} // namespace clang::tidy::bugprone
diff --git a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
new file mode 100644
index 000000000000000..542b1c50dc782e7
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
@@ -0,0 +1,37 @@
+//===--- CastingThroughVoidCheck.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_BUGPRONE_CASTINGTHROUGHVOIDCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_CASTINGTHROUGHVOIDCHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang::tidy::bugprone {
+
+/// A check detects usage of ``static_cast`` pointer to the other pointer
+/// throght
+/// ``static_cast`` to ``void *`` in C++ code.
+/// For the user-facing documentation see:
+///
http://clang.llvm.org/extra/clang-tidy/checks/bugprone/casting-through-void.html
+class CastingThroughVoidCheck : public ClangTidyCheck {
+public:
+ CastingThroughVoidCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+ bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
+ return LangOpts.CPlusPlus;
+ }
+ std::optional<TraversalKind> getCheckTraversalKind() const override {
+ return TK_IgnoreUnlessSpelledInSource;
+ }
+};
+
+} // namespace clang::tidy::bugprone
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_CASTINGTHROUGHVOIDCHECK_H
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst
b/clang-tools-extra/docs/ReleaseNotes.rst
index af164d0462d52c1..3ceb844a036240c 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -125,6 +125,12 @@ Improvements to clang-tidy
New checks
^^^^^^^^^^
+- New :doc:`bugprone-casting-through-void
+ <clang-tidy/checks/bugprone/casting-through-void>` check.
+
+ Detects usage of ``static_cast`` pointer to the other pointer throght
+ ``static_cast`` to ``void *`` in C++ code.
+
- New :doc:`bugprone-compare-pointer-to-member-virtual-function
<clang-tidy/checks/bugprone/compare-pointer-to-member-virtual-function>`
check.
diff --git
a/clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
b/clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
new file mode 100644
index 000000000000000..4a20d8eb9b41c8b
--- /dev/null
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
@@ -0,0 +1,11 @@
+.. title:: clang-tidy - bugprone-casting-through-void
+
+bugprone-casting-through-void
+=============================
+
+A check detects usage of ``static_cast`` pointer to the other pointer throght
+``static_cast`` to ``void *`` in C++ code.
+
+Use of these casts can violate type safety and cause the program to access a
+variable that is actually of type ``X`` to be accessed as if it were of an
+unrelated type ``Z``.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst
b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index 2125ebd7a213c15..fa95bffdc45f9cb 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -82,6 +82,7 @@ Clang-Tidy Checks
:doc:`bugprone-bad-signal-to-kill-thread
<bugprone/bad-signal-to-kill-thread>`,
:doc:`bugprone-bool-pointer-implicit-conversion
<bugprone/bool-pointer-implicit-conversion>`, "Yes"
:doc:`bugprone-branch-clone <bugprone/branch-clone>`,
+ :doc:`bugprone-casting-through-void <bugprone/casting-through-void>`, "Yes"
:doc:`bugprone-compare-pointer-to-member-virtual-function
<bugprone/compare-pointer-to-member-virtual-function>`,
:doc:`bugprone-copy-constructor-init <bugprone/copy-constructor-init>`,
"Yes"
:doc:`bugprone-dangling-handle <bugprone/dangling-handle>`,
diff --git
a/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
b/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
new file mode 100644
index 000000000000000..f9e8c57201ee802
--- /dev/null
+++
b/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
@@ -0,0 +1,18 @@
+// RUN: %check_clang_tidy %s bugprone-casting-through-void %t
+
+using T = void*;
+
+void test() {
+ int i = 100;
+ double d = 100;
+
+ static_cast<int *>(static_cast<void *>(&d));
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not cast double * to int *
through void * [bugprone-casting-through-void]
+
+ static_cast<int *>(static_cast<T>(&d));
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not cast double * to int *
through void * [bugprone-casting-through-void]
+
+ static_cast<int *>(static_cast<void *>(&i));
+
+ static_cast<void *>(static_cast<void *>(&i));
+}
>From 77d37e9a95191cfbeb7f4fe7504f86c6dfd0ad2e Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0...@163.com>
Date: Wed, 18 Oct 2023 22:43:03 +0800
Subject: [PATCH 2/6] fix
---
.../bugprone/CastingThroughVoidCheck.cpp | 18 ++++++++----------
.../docs/clang-tidy/checks/list.rst | 2 +-
.../checkers/bugprone/casting-through-void.cpp | 4 ++--
3 files changed, 11 insertions(+), 13 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
index 7b9cd7dd51fc47f..f1d6c9170dbcbfe 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
@@ -26,21 +26,19 @@ void CastingThroughVoidCheck::registerMatchers(MatchFinder
*Finder) {
hasSourceExpression(
explicitCastExpr(hasSourceExpression(expr(
hasType(qualType().bind("source_type")))),
- hasDestinationType(pointsTo(voidType())))))
- .bind("cast"),
+ hasDestinationType(pointsTo(voidType())))
+ .bind("cast"))),
this);
}
void CastingThroughVoidCheck::check(const MatchFinder::MatchResult &Result) {
- ASTContext *Context = Result.Context;
- const auto *CE = Result.Nodes.getNodeAs<ExplicitCastExpr>("cast");
- const auto *TT = Result.Nodes.getNodeAs<QualType>("target_type");
- const auto *ST = Result.Nodes.getNodeAs<QualType>("source_type");
- if (Context->hasSameType(*TT, *ST))
+ const auto TT = *Result.Nodes.getNodeAs<QualType>("target_type");
+ const auto ST = *Result.Nodes.getNodeAs<QualType>("source_type");
+ if (Result.Context->hasSameType(TT, ST))
return;
- diag(CE->getSourceRange().getBegin(), "do not cast %0 to %1 through void *",
- DiagnosticIDs::Level::Warning)
- << ST->getAsString() << TT->getAsString();
+ const auto *CE = Result.Nodes.getNodeAs<ExplicitCastExpr>("cast");
+ diag(CE->getSourceRange().getBegin(), "do not cast %0 to %1 through 'void*'")
+ << ST << TT;
}
} // namespace clang::tidy::bugprone
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst
b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index fa95bffdc45f9cb..0ce25772aa5b66b 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -82,7 +82,7 @@ Clang-Tidy Checks
:doc:`bugprone-bad-signal-to-kill-thread
<bugprone/bad-signal-to-kill-thread>`,
:doc:`bugprone-bool-pointer-implicit-conversion
<bugprone/bool-pointer-implicit-conversion>`, "Yes"
:doc:`bugprone-branch-clone <bugprone/branch-clone>`,
- :doc:`bugprone-casting-through-void <bugprone/casting-through-void>`, "Yes"
+ :doc:`bugprone-casting-through-void <bugprone/casting-through-void>`,
:doc:`bugprone-compare-pointer-to-member-virtual-function
<bugprone/compare-pointer-to-member-virtual-function>`,
:doc:`bugprone-copy-constructor-init <bugprone/copy-constructor-init>`,
"Yes"
:doc:`bugprone-dangling-handle <bugprone/dangling-handle>`,
diff --git
a/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
b/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
index f9e8c57201ee802..74265fce3f59068 100644
---
a/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
+++
b/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
@@ -7,10 +7,10 @@ void test() {
double d = 100;
static_cast<int *>(static_cast<void *>(&d));
- // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not cast double * to int *
through void * [bugprone-casting-through-void]
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
static_cast<int *>(static_cast<T>(&d));
- // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not cast double * to int *
through void * [bugprone-casting-through-void]
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
static_cast<int *>(static_cast<void *>(&i));
>From a432aed9e92e9cd3d4302c09e39fb4eac6dcd943 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0...@163.com>
Date: Wed, 18 Oct 2023 23:30:20 +0800
Subject: [PATCH 3/6] add test
---
.../bugprone/CastingThroughVoidCheck.cpp | 7 +-
.../bugprone/casting-through-void.cpp | 81 ++++++++++++++++++-
2 files changed, 83 insertions(+), 5 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
index f1d6c9170dbcbfe..4ce4e3c773f6766 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
@@ -34,7 +34,12 @@ void CastingThroughVoidCheck::registerMatchers(MatchFinder
*Finder) {
void CastingThroughVoidCheck::check(const MatchFinder::MatchResult &Result) {
const auto TT = *Result.Nodes.getNodeAs<QualType>("target_type");
const auto ST = *Result.Nodes.getNodeAs<QualType>("source_type");
- if (Result.Context->hasSameType(TT, ST))
+ if (Result.Context->hasSameType(TT->getUnqualifiedDesugaredType(),
+ ST->getUnqualifiedDesugaredType()))
+ return;
+ if (Result.Context->hasSameType(
+ TT->getPointeeType()->getUnqualifiedDesugaredType(),
+ ST->getPointeeType()->getUnqualifiedDesugaredType()))
return;
const auto *CE = Result.Nodes.getNodeAs<ExplicitCastExpr>("cast");
diag(CE->getSourceRange().getBegin(), "do not cast %0 to %1 through 'void*'")
diff --git
a/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
b/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
index 74265fce3f59068..4edb33310f45ec7 100644
---
a/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
+++
b/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
@@ -1,11 +1,14 @@
// RUN: %check_clang_tidy %s bugprone-casting-through-void %t
using T = void*;
+using CT = const void*;
-void test() {
- int i = 100;
- double d = 100;
+int i = 100;
+double d = 100;
+const int ci = 100;
+const double cd = 100;
+void normal_test() {
static_cast<int *>(static_cast<void *>(&d));
// CHECK-MESSAGES: :[[@LINE-1]]:22: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
@@ -13,6 +16,76 @@ void test() {
// CHECK-MESSAGES: :[[@LINE-1]]:22: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
static_cast<int *>(static_cast<void *>(&i));
-
static_cast<void *>(static_cast<void *>(&i));
}
+
+void const_pointer_test() {
+ static_cast<int *const>(static_cast<void *>(&d));
+ // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: do not cast 'double *' to 'int
*const' through 'void*' [bugprone-casting-through-void]
+
+ static_cast<int *const>(static_cast<T>(&d));
+ // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: do not cast 'double *' to 'int
*const' through 'void*' [bugprone-casting-through-void]
+
+ static_cast<int *const>(static_cast<void *>(&i));
+ static_cast<void *const>(static_cast<void *>(&i));
+}
+
+void const_test() {
+ static_cast<const int *>(static_cast<const void *>(&d));
+ // CHECK-MESSAGES: :[[@LINE-1]]:28: warning: do not cast 'double *' to
'const int *' through 'void*' [bugprone-casting-through-void]
+
+ static_cast<const int *>(static_cast<const T>(&d));
+ // CHECK-MESSAGES: :[[@LINE-1]]:28: warning: do not cast 'double *' to
'const int *' through 'void*' [bugprone-casting-through-void]
+
+ static_cast<const int *>(static_cast<const void *>(&i));
+ static_cast<const void *>(static_cast<const void *>(&i));
+
+ static_cast<const int *>(static_cast<const void *>(&cd));
+ // CHECK-MESSAGES: :[[@LINE-1]]:28: warning: do not cast 'const double *' to
'const int *' through 'void*' [bugprone-casting-through-void]
+
+ static_cast<const int *>(static_cast<const CT>(&cd));
+ // CHECK-MESSAGES: :[[@LINE-1]]:28: warning: do not cast 'const double *' to
'const int *' through 'void*' [bugprone-casting-through-void]
+
+ static_cast<const int *>(static_cast<const void *>(&ci));
+ static_cast<const void *>(static_cast<const void *>(&ci));
+}
+
+
+void reinterpret_cast_test() {
+ static_cast<int *>(reinterpret_cast<void *>(&d));
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
+ reinterpret_cast<int *>(static_cast<void *>(&d));
+ // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
+ reinterpret_cast<int *>(reinterpret_cast<void *>(&d));
+ // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
+
+ static_cast<int *>(reinterpret_cast<void *>(&i));
+ static_cast<void *>(reinterpret_cast<void *>(&i));
+ reinterpret_cast<int *>(reinterpret_cast<void *>(&i));
+ reinterpret_cast<void *>(reinterpret_cast<void *>(&i));
+ static_cast<int *>(reinterpret_cast<void *>(&i));
+ static_cast<void *>(reinterpret_cast<void *>(&i));
+}
+
+void c_style_cast_test() {
+ static_cast<int *>((void *)&d);
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
+ (int *)(void *)&d;
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
+ static_cast<int *>((void *)&d);
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
+
+ static_cast<int *>(reinterpret_cast<void *>(&i));
+ static_cast<void *>(reinterpret_cast<void *>(&i));
+}
+
+struct A {
+ A(void*);
+};
+void cxx_functional_cast() {
+ A(static_cast<void*>(&i));
+}
+
+void bit_cast() {
+ __builtin_bit_cast(int *, static_cast<void *>(&i));
+}
>From 858aff0c29fb8946572c4dc749cfa99ac6f75320 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0...@163.com>
Date: Wed, 18 Oct 2023 23:47:33 +0800
Subject: [PATCH 4/6] support __builtin_bit_cast
---
.../clang-tidy/bugprone/CastingThroughVoidCheck.cpp | 3 ++-
.../clang-tidy/bugprone/CastingThroughVoidCheck.h | 8 ++------
clang-tools-extra/docs/ReleaseNotes.rst | 4 ++--
.../checks/bugprone/casting-through-void.rst | 4 ++--
.../checkers/bugprone/casting-through-void.cpp | 2 +-
clang/include/clang/ASTMatchers/ASTMatchers.h | 10 ++++++++++
6 files changed, 19 insertions(+), 12 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
index 4ce4e3c773f6766..4ac0eda72dc30ad 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.cpp
@@ -27,7 +27,8 @@ void CastingThroughVoidCheck::registerMatchers(MatchFinder
*Finder) {
explicitCastExpr(hasSourceExpression(expr(
hasType(qualType().bind("source_type")))),
hasDestinationType(pointsTo(voidType())))
- .bind("cast"))),
+ .bind("cast")),
+ unless(builtinBitCastExpr())),
this);
}
diff --git a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
index 542b1c50dc782e7..369242036115814 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
@@ -13,9 +13,8 @@
namespace clang::tidy::bugprone {
-/// A check detects usage of ``static_cast`` pointer to the other pointer
-/// throght
-/// ``static_cast`` to ``void *`` in C++ code.
+/// A check detects usage of cast pointer to the other pointer throght cast to
+/// ``void *`` in C/C++ code.
/// For the user-facing documentation see:
///
http://clang.llvm.org/extra/clang-tidy/checks/bugprone/casting-through-void.html
class CastingThroughVoidCheck : public ClangTidyCheck {
@@ -24,9 +23,6 @@ class CastingThroughVoidCheck : public ClangTidyCheck {
: ClangTidyCheck(Name, Context) {}
void registerMatchers(ast_matchers::MatchFinder *Finder) override;
void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
- bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
- return LangOpts.CPlusPlus;
- }
std::optional<TraversalKind> getCheckTraversalKind() const override {
return TK_IgnoreUnlessSpelledInSource;
}
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst
b/clang-tools-extra/docs/ReleaseNotes.rst
index 3ceb844a036240c..08ba3ca79aa87ef 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -128,8 +128,8 @@ New checks
- New :doc:`bugprone-casting-through-void
<clang-tidy/checks/bugprone/casting-through-void>` check.
- Detects usage of ``static_cast`` pointer to the other pointer throght
- ``static_cast`` to ``void *`` in C++ code.
+ Detects usage of cast pointer to the other pointer throght cast to
+ ``void *`` in C/C++ code.
- New :doc:`bugprone-compare-pointer-to-member-virtual-function
<clang-tidy/checks/bugprone/compare-pointer-to-member-virtual-function>`
check.
diff --git
a/clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
b/clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
index 4a20d8eb9b41c8b..4c5e70533fa3bc6 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
@@ -3,8 +3,8 @@
bugprone-casting-through-void
=============================
-A check detects usage of ``static_cast`` pointer to the other pointer throght
-``static_cast`` to ``void *`` in C++ code.
+A check detects usage of cast pointer to the other pointer throght cast to
+``void *`` in C/C++ code.
Use of these casts can violate type safety and cause the program to access a
variable that is actually of type ``X`` to be accessed as if it were of an
diff --git
a/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
b/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
index 4edb33310f45ec7..8cf15c3b08cdb14 100644
---
a/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
+++
b/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
@@ -87,5 +87,5 @@ void cxx_functional_cast() {
}
void bit_cast() {
- __builtin_bit_cast(int *, static_cast<void *>(&i));
+ __builtin_bit_cast(int *, static_cast<void *>(&d));
}
diff --git a/clang/include/clang/ASTMatchers/ASTMatchers.h
b/clang/include/clang/ASTMatchers/ASTMatchers.h
index 82a26356c58f556..1dad8594ec92843 100644
--- a/clang/include/clang/ASTMatchers/ASTMatchers.h
+++ b/clang/include/clang/ASTMatchers/ASTMatchers.h
@@ -2732,6 +2732,16 @@ extern const internal::VariadicDynCastAllOfMatcher<Stmt,
CastExpr> castExpr;
extern const internal::VariadicDynCastAllOfMatcher<Stmt, CXXFunctionalCastExpr>
cxxFunctionalCastExpr;
+/// Matches a builtin bit cast expression.
+///
+/// Example: Matches __builtin_bit_cast(double, i) in
+/// \code
+/// int64_t i = 100;
+/// double d = __builtin_bit_cast(double, i);
+/// \endcode
+extern const internal::VariadicDynCastAllOfMatcher<Stmt, BuiltinBitCastExpr>
+ builtinBitCastExpr;
+
/// Matches functional cast expressions having N != 1 arguments
///
/// Example: Matches Foo(bar, bar)
>From 01c3ab74d3c3f3828366fb9e472cb2e4c6b93466 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0...@163.com>
Date: Thu, 19 Oct 2023 00:11:28 +0800
Subject: [PATCH 5/6] add functional cast test
---
.../bugprone/casting-through-void.cpp | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
diff --git
a/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
b/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
index 8cf15c3b08cdb14..f36f51a88d183e2 100644
---
a/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
+++
b/clang-tools-extra/test/clang-tidy/checkers/bugprone/casting-through-void.cpp
@@ -1,7 +1,7 @@
// RUN: %check_clang_tidy %s bugprone-casting-through-void %t
-using T = void*;
-using CT = const void*;
+using V = void*;
+using CV = const void*;
int i = 100;
double d = 100;
@@ -12,7 +12,7 @@ void normal_test() {
static_cast<int *>(static_cast<void *>(&d));
// CHECK-MESSAGES: :[[@LINE-1]]:22: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
- static_cast<int *>(static_cast<T>(&d));
+ static_cast<int *>(static_cast<V>(&d));
// CHECK-MESSAGES: :[[@LINE-1]]:22: warning: do not cast 'double *' to 'int
*' through 'void*' [bugprone-casting-through-void]
static_cast<int *>(static_cast<void *>(&i));
@@ -23,7 +23,7 @@ void const_pointer_test() {
static_cast<int *const>(static_cast<void *>(&d));
// CHECK-MESSAGES: :[[@LINE-1]]:27: warning: do not cast 'double *' to 'int
*const' through 'void*' [bugprone-casting-through-void]
- static_cast<int *const>(static_cast<T>(&d));
+ static_cast<int *const>(static_cast<V>(&d));
// CHECK-MESSAGES: :[[@LINE-1]]:27: warning: do not cast 'double *' to 'int
*const' through 'void*' [bugprone-casting-through-void]
static_cast<int *const>(static_cast<void *>(&i));
@@ -34,7 +34,7 @@ void const_test() {
static_cast<const int *>(static_cast<const void *>(&d));
// CHECK-MESSAGES: :[[@LINE-1]]:28: warning: do not cast 'double *' to
'const int *' through 'void*' [bugprone-casting-through-void]
- static_cast<const int *>(static_cast<const T>(&d));
+ static_cast<const int *>(static_cast<const V>(&d));
// CHECK-MESSAGES: :[[@LINE-1]]:28: warning: do not cast 'double *' to
'const int *' through 'void*' [bugprone-casting-through-void]
static_cast<const int *>(static_cast<const void *>(&i));
@@ -43,7 +43,7 @@ void const_test() {
static_cast<const int *>(static_cast<const void *>(&cd));
// CHECK-MESSAGES: :[[@LINE-1]]:28: warning: do not cast 'const double *' to
'const int *' through 'void*' [bugprone-casting-through-void]
- static_cast<const int *>(static_cast<const CT>(&cd));
+ static_cast<const int *>(static_cast<const CV>(&cd));
// CHECK-MESSAGES: :[[@LINE-1]]:28: warning: do not cast 'const double *' to
'const int *' through 'void*' [bugprone-casting-through-void]
static_cast<const int *>(static_cast<const void *>(&ci));
@@ -82,8 +82,13 @@ void c_style_cast_test() {
struct A {
A(void*);
};
+using I = int *;
+using D = double *;
void cxx_functional_cast() {
- A(static_cast<void*>(&i));
+ A(static_cast<void*>(&d));
+ D(static_cast<void*>(&d));
+ I(static_cast<void*>(&d));
+ // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: do not cast 'double *' to 'I'
(aka 'int *') through 'void*' [bugprone-casting-through-void]
}
void bit_cast() {
>From e073d026aa7e12720af1d1760b8c49e22ae970d8 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0...@163.com>
Date: Thu, 19 Oct 2023 00:20:36 +0800
Subject: [PATCH 6/6] doc
---
.../bugprone/CastingThroughVoidCheck.h | 3 +-
clang-tools-extra/docs/ReleaseNotes.rst | 3 +-
.../checks/bugprone/casting-through-void.rst | 31 ++++++++++++++++---
3 files changed, 28 insertions(+), 9 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
index 369242036115814..86ed84275006f92 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
+++ b/clang-tools-extra/clang-tidy/bugprone/CastingThroughVoidCheck.h
@@ -13,8 +13,7 @@
namespace clang::tidy::bugprone {
-/// A check detects usage of cast pointer to the other pointer throght cast to
-/// ``void *`` in C/C++ code.
+/// A check detects unsafe or redundant two-step casting operations involving
``void*``.
/// For the user-facing documentation see:
///
http://clang.llvm.org/extra/clang-tidy/checks/bugprone/casting-through-void.html
class CastingThroughVoidCheck : public ClangTidyCheck {
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst
b/clang-tools-extra/docs/ReleaseNotes.rst
index 08ba3ca79aa87ef..e3943b858ee4596 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -128,8 +128,7 @@ New checks
- New :doc:`bugprone-casting-through-void
<clang-tidy/checks/bugprone/casting-through-void>` check.
- Detects usage of cast pointer to the other pointer throght cast to
- ``void *`` in C/C++ code.
+ Detects unsafe or redundant two-step casting operations involving ``void*``.
- New :doc:`bugprone-compare-pointer-to-member-virtual-function
<clang-tidy/checks/bugprone/compare-pointer-to-member-virtual-function>`
check.
diff --git
a/clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
b/clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
index 4c5e70533fa3bc6..c9f851b0679c247 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/casting-through-void.rst
@@ -3,9 +3,30 @@
bugprone-casting-through-void
=============================
-A check detects usage of cast pointer to the other pointer throght cast to
-``void *`` in C/C++ code.
+A check detects unsafe or redundant two-step casting operations involving
``void*``.
-Use of these casts can violate type safety and cause the program to access a
-variable that is actually of type ``X`` to be accessed as if it were of an
-unrelated type ``Z``.
+Two-step type conversions via void* are discouraged for several reasons.
+
+1. They obscure code and impede its understandability, complicating
maintenance.
+2. These conversions bypass valuable compiler support, erasing warnings related
+ to pointer alignment. It may violate strict aliasing rule and leading to
+ undefined behavior.
+3. In scenarios involving multiple inheritance, ambiguity and unexpected
outcomes
+ can arise due to the loss of type information, posing runtime issues.
+
+In summary, avoiding two-step type conversions through void* ensures clearer
code,
+maintains essential compiler warnings, and prevents ambiguity and potential
runtime
+errors, particularly in complex inheritance scenarios.
+
+Examples:
+
+.. code-block:: c++
+ using IntegerPointer = int *;
+ double *ptr;
+
+ static_cast<IntegerPointer>(static_cast<void *>(ptr)); // WRONG
+ reinterpret_cast<IntegerPointer>(reinterpret_cast<void *>(ptr)); // WRONG
+ (IntegerPointer)(void *)ptr; // WRONG
+ IntegerPointer(static_cast<void *>(ptr)); // WRONG
+
+ __bultin_bit_cast(IntegerPointer, static_cast<void *>(ptr)) // GOOD,
__builtin_bit_cast is used to implement std::bit_cast
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