mgehre created this revision.
mgehre added reviewers: alexfh, sbenza, bkramer, aaron.ballman.
mgehre added a subscriber: cfe-commits.
This check flags all array to pointer decays.
Pointers should not be used as arrays. array_view is a bounds-checked,
safe alternative to using pointers to access arrays.
This rule is part of the "Bounds safety" profile of the C++ Core
Guidelines, see
https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#-bounds3-no-array-to-pointer-decay
http://reviews.llvm.org/D13640
Files:
clang-tidy/cppcoreguidelines/CMakeLists.txt
clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp
clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.h
docs/clang-tidy/checks/cppcoreguidelines-pro-bounds-array-to-pointer-decay.rst
docs/clang-tidy/checks/list.rst
test/clang-tidy/cppcoreguidelines-pro-bounds-array-to-pointer-decay.cpp
Index: test/clang-tidy/cppcoreguidelines-pro-bounds-array-to-pointer-decay.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/cppcoreguidelines-pro-bounds-array-to-pointer-decay.cpp
@@ -0,0 +1,26 @@
+// RUN: %python %S/check_clang_tidy.py %s cppcoreguidelines-pro-bounds-array-to-pointer-decay %t
+
+void pointerfun(int* p);
+void arrayfun(int p[]);
+
+void f()
+{
+ int a[5];
+ pointerfun(a);
+ // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: do not (implicitly) convert an array to a pointer [cppcoreguidelines-pro-bounds-array-to-pointer-decay]
+ pointerfun((int*)a);
+ // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: do not (implicitly) convert an array to a pointer
+ arrayfun(a);
+ // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: do not (implicitly) convert an array to a pointer
+
+ int i = a[0]; // OK
+ pointerfun(&a[0]); // OK
+
+ for(auto e : a ) // OK, iteration internally decays array to pointer
+ ;
+}
+
+const char* g()
+{
+ return "clang"; // OK, decay string literal to pointer
+}
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -4,6 +4,7 @@
.. toctree::
cert-setlongjmp
cert-variadic-function-def
+ cppcoreguidelines-pro-bounds-array-to-pointer-decay
cppcoreguidelines-pro-type-const-cast
cppcoreguidelines-pro-type-reinterpret-cast
google-build-explicit-make-pair
Index: docs/clang-tidy/checks/cppcoreguidelines-pro-bounds-array-to-pointer-decay.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/cppcoreguidelines-pro-bounds-array-to-pointer-decay.rst
@@ -0,0 +1,9 @@
+cppcoreguidelines-pro-bounds-array-to-pointer-decay
+===================================================
+
+This check flags all array to pointer decays.
+
+Pointers should not be used as arrays. array_view is a bounds-checked, safe alternative to using pointers to access arrays.
+
+This rule is part of the "Bounds safety" profile of the C++ Core Guidelines, see
+https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#-bounds3-no-array-to-pointer-decay
Index: clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.h
@@ -0,0 +1,34 @@
+//===--- ProBoundsArrayToPointerDecayCheck.h - clang-tidy--------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_BOUNDS_ARRAY_TO_POINTER_DECAY_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_BOUNDS_ARRAY_TO_POINTER_DECAY_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+
+/// This check flags all array to pointer decays
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines-pro-bounds-array-to-pointer-decay.html
+class ProBoundsArrayToPointerDecayCheck : public ClangTidyCheck {
+public:
+ ProBoundsArrayToPointerDecayCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_BOUNDS_ARRAY_TO_POINTER_DECAY_H
+
Index: clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp
@@ -0,0 +1,45 @@
+//===--- ProBoundsArrayToPointerDecayCheck.cpp - clang-tidy----------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ProBoundsArrayToPointerDecayCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+
+void ProBoundsArrayToPointerDecayCheck::registerMatchers(MatchFinder *Finder) {
+ if (!getLangOpts().CPlusPlus)
+ return;
+
+ // The only allowed array to pointer decay if
+ // 1) just before array subscription
+ // 2) inside a range-for over an array
+ // 3) it converts a string literal to a pointer
+ Finder->addMatcher(
+ implicitCastExpr(unless(hasParent(arraySubscriptExpr())),
+ unless(hasSourceExpression(declRefExpr(to(varDecl(hasName("__range")))))),
+ unless(hasSourceExpression(stringLiteral()))
+ ).bind("cast"),
+ this);
+}
+
+void ProBoundsArrayToPointerDecayCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *MatchedCast = Result.Nodes.getNodeAs<ImplicitCastExpr>("cast");
+ if (MatchedCast->getCastKind() != CK_ArrayToPointerDecay)
+ return;
+
+ diag(MatchedCast->getExprLoc(), "do not (implicitly) convert an array to a pointer");
+}
+
+} // namespace tidy
+} // namespace clang
+
Index: clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
===================================================================
--- clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
+++ clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
@@ -10,6 +10,7 @@
#include "../ClangTidy.h"
#include "../ClangTidyModule.h"
#include "../ClangTidyModuleRegistry.h"
+#include "ProBoundsArrayToPointerDecayCheck.h"
#include "ProTypeConstCastCheck.h"
#include "ProTypeReinterpretCastCheck.h"
@@ -21,6 +22,8 @@
class CppCoreGuidelinesModule : public ClangTidyModule {
public:
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
+ CheckFactories.registerCheck<ProBoundsArrayToPointerDecayCheck>(
+ "cppcoreguidelines-pro-bounds-array-to-pointer-decay");
CheckFactories.registerCheck<ProTypeConstCastCheck>(
"cppcoreguidelines-pro-type-const-cast");
CheckFactories.registerCheck<ProTypeReinterpretCastCheck>(
Index: clang-tidy/cppcoreguidelines/CMakeLists.txt
===================================================================
--- clang-tidy/cppcoreguidelines/CMakeLists.txt
+++ clang-tidy/cppcoreguidelines/CMakeLists.txt
@@ -2,6 +2,7 @@
add_clang_library(clangTidyCppCoreGuidelinesModule
CppCoreGuidelinesTidyModule.cpp
+ ProBoundsArrayToPointerDecayCheck.cpp
ProTypeConstCastCheck.cpp
ProTypeReinterpretCastCheck.cpp
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