jankratochvil updated this revision to Diff 234787.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D71707/new/
https://reviews.llvm.org/D71707
Files:
clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
clang-tools-extra/clang-tidy/bugprone/PointerCastWideningCheck.cpp
clang-tools-extra/clang-tidy/bugprone/PointerCastWideningCheck.h
clang-tools-extra/docs/ReleaseNotes.rst
clang-tools-extra/docs/clang-tidy/checks/bugprone-pointer-cast-widening.rst
clang-tools-extra/docs/clang-tidy/checks/list.rst
clang-tools-extra/test/clang-tidy/checkers/bugprone-pointer-cast-widening.cpp
Index: clang-tools-extra/test/clang-tidy/checkers/bugprone-pointer-cast-widening.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/checkers/bugprone-pointer-cast-widening.cpp
@@ -0,0 +1,17 @@
+// RUN: %check_clang_tidy %s bugprone-pointer-cast-widening %t
+
+#include <stdint.h>
+
+void test() {
+ void *p = 0;
+ uint64_t u64 = (uint64_t)p;
+ // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: do not use cast of a pointer 'void *' to non-uintptr_t 'uint64_t' (aka 'unsigned long') which may sign-extend [bugprone-pointer-cast-widening]
+ uint64_t u64r = reinterpret_cast<uint64_t>(p);
+ // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: do not use cast of a pointer 'void *' to non-uintptr_t 'uint64_t' (aka 'unsigned long') which may sign-extend [bugprone-pointer-cast-widening]
+ intptr_t ip = reinterpret_cast<intptr_t>(p);
+ // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: do not use cast of a pointer 'void *' to non-uintptr_t 'intptr_t' (aka 'long') which may sign-extend [bugprone-pointer-cast-widening]
+ uintptr_t up = (uintptr_t)p;
+ typedef uintptr_t t1;
+ typedef t1 t2;
+ t2 t = (t2)p;
+}
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
@@ -62,6 +62,7 @@
bugprone-multiple-statement-macro
bugprone-not-null-terminated-result
bugprone-parent-virtual-call
+ bugprone-pointer-cast-widening
bugprone-posix-return
bugprone-sizeof-container
bugprone-sizeof-expression
Index: clang-tools-extra/docs/clang-tidy/checks/bugprone-pointer-cast-widening.rst
===================================================================
--- /dev/null
+++ clang-tools-extra/docs/clang-tidy/checks/bugprone-pointer-cast-widening.rst
@@ -0,0 +1,26 @@
+.. title:: clang-tidy - bugprone-pointer-cast-widening
+
+bugprone-pointer-cast-widening
+==============================
+
+Checks for cast of a pointer to wider (even unsigned) integer as it
+sign-extends the pointer which happens on 32-bit hosts for 64-bit integers.
+The buggy behavior are 32-bit addresses printed like ``0xffffffffd56b5d60``.
+
+Casting from 32-bit ``void *`` to ``uint64_t`` requires an intermediate cast to
+``uintptr_t`` otherwise the pointer gets sign-extended:
+
+.. code-block:: c++
+
+ void *p=(void *)0x80000000;
+ printf( "%p" "\n", p );//0x80000000
+ printf("0x%" PRIxPTR "\n", (uintptr_t) p );//0x80000000
+ printf("0x%" PRIxPTR "\n",reinterpret_cast<uintptr_t>(p));//0x80000000
+ // ^^^^^^^^^^^^^^^^^^^^^^^^^^^ recommended
+ printf("0x%" PRIx64 "\n",reinterpret_cast<uint64_t >(p));//0xffffffff80000000
+ printf("0x%" PRIx64 "\n", (uint64_t ) p );//0xffffffff80000000
+ printf("0x%" PRIx64 "\n", (uint64_t)(uintptr_t) p );//0x80000000
+
+The only supported cast from a pointer to integer is ``uintptr_t``.
+
+Casting to ``int64_t`` is discouraged as it leads to the sign-extensions again.
Index: clang-tools-extra/docs/ReleaseNotes.rst
===================================================================
--- clang-tools-extra/docs/ReleaseNotes.rst
+++ clang-tools-extra/docs/ReleaseNotes.rst
@@ -94,6 +94,12 @@
Without the null terminator it can result in undefined behaviour when the
string is read.
+- New :doc:`bugprone-pointer-cast-widening
+ <clang-tidy/checks/bugprone-pointer-cast-widening>` check
+
+ Checks for cast of a pointer to wider (even unsigned) integer as it
+ sign-extends the pointer which happens on 32-bit hosts for 64-bit integers.
+
- New :doc:`cert-mem57-cpp
<clang-tidy/checks/cert-mem57-cpp>` check.
Index: clang-tools-extra/clang-tidy/bugprone/PointerCastWideningCheck.h
===================================================================
--- /dev/null
+++ clang-tools-extra/clang-tidy/bugprone/PointerCastWideningCheck.h
@@ -0,0 +1,32 @@
+//===--- PointerCastWideningCheck.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_POINTER_CAST_WIDENING_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_POINTER_CAST_WIDENING_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace bugprone {
+
+/// Checks for cast of a pointer to wider (even unsigned) integer as it
+/// sign-extends the pointer which happens on 32-bit hosts for 64-bit integers.
+class PointerCastWideningCheck : public ClangTidyCheck {
+public:
+ PointerCastWideningCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace bugprone
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_POINTER_CAST_WIDENING_H
Index: clang-tools-extra/clang-tidy/bugprone/PointerCastWideningCheck.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/clang-tidy/bugprone/PointerCastWideningCheck.cpp
@@ -0,0 +1,54 @@
+//===--- PointerCastWideningCheck.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 "PointerCastWideningCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace bugprone {
+
+void PointerCastWideningCheck::registerMatchers(MatchFinder *Finder) {
+ if (!getLangOpts().CPlusPlus && !getLangOpts().C99)
+ return;
+
+ Finder->addMatcher(castExpr(unless(isInTemplateInstantiation())).bind("cast"),
+ this);
+}
+
+void PointerCastWideningCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *MatchedCast = Result.Nodes.getNodeAs<CastExpr>("cast");
+
+ if (MatchedCast->getCastKind() != CK_PointerToIntegral)
+ return;
+
+ QualType DestType = MatchedCast->getType();
+ for (QualType DestTypeCheck = DestType;;) {
+ if (DestTypeCheck.getAsString() == "uintptr_t")
+ return;
+ QualType DestTypeNext =
+ DestTypeCheck.getSingleStepDesugaredType(*Result.Context);
+ if (DestTypeNext == DestTypeCheck)
+ break;
+ DestTypeCheck = DestTypeNext;
+ }
+
+ QualType SourceType = MatchedCast->getSubExpr()->getType();
+
+ diag(MatchedCast->getBeginLoc(), "do not use cast of a pointer %0 to "
+ "non-uintptr_t %1 which may sign-extend")
+ << SourceType << DestType;
+}
+
+} // namespace bugprone
+} // namespace tidy
+} // namespace clang
Index: clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
===================================================================
--- clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
+++ clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
@@ -27,6 +27,7 @@
MultipleStatementMacroCheck.cpp
NotNullTerminatedResultCheck.cpp
ParentVirtualCallCheck.cpp
+ PointerCastWideningCheck.cpp
PosixReturnCheck.cpp
SizeofContainerCheck.cpp
SizeofExpressionCheck.cpp
Index: clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
===================================================================
--- clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
+++ clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
@@ -35,6 +35,7 @@
#include "MultipleStatementMacroCheck.h"
#include "NotNullTerminatedResultCheck.h"
#include "ParentVirtualCallCheck.h"
+#include "PointerCastWideningCheck.h"
#include "PosixReturnCheck.h"
#include "SizeofContainerCheck.h"
#include "SizeofExpressionCheck.h"
@@ -117,6 +118,8 @@
"bugprone-not-null-terminated-result");
CheckFactories.registerCheck<ParentVirtualCallCheck>(
"bugprone-parent-virtual-call");
+ CheckFactories.registerCheck<PointerCastWideningCheck>(
+ "bugprone-pointer-cast-widening");
CheckFactories.registerCheck<PosixReturnCheck>(
"bugprone-posix-return");
CheckFactories.registerCheck<SizeofContainerCheck>(
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