mgehre updated this revision to Diff 38353.
mgehre marked an inline comment as done.
mgehre added a comment.
Do not flag explicit casts
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 +1,41 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-pro-bounds-array-to-pointer-decay %t
+#include <stddef.h>
+
+namespace gsl {
+template <class T>
+class array_view {
+public:
+ template <class U, size_t N>
+ array_view(U (&arr)[N]);
+};
+}
+
+void pointerfun(int *p);
+void arrayfun(int p[]);
+void arrayviewfun(gsl::array_view<int> &p);
+size_t s();
+
+void f() {
+ int a[5];
+ pointerfun(a);
+ // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay]
+ pointerfun((int *)a); // OK, explicit cast
+ arrayfun(a);
+ // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: do not implicitly decay an array into a pointer
+
+ pointerfun(a + s() - 10); // Convert to &a[g() - 10];
+ // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: do not implicitly decay an array into a pointer
+
+ gsl::array_view<int> av(a);
+ arrayviewfun(av); // OK
+
+ int i = a[0]; // OK
+ pointerfun(&a[0]); // OK
+
+ for (auto &e : a) // OK, iteration internally decays array to pointer
+ e = 1;
+}
+
+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-bounds-pointer-arithmetic
cppcoreguidelines-pro-type-const-cast
cppcoreguidelines-pro-type-reinterpret-cast
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 +1,57 @@
+//===--- 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 {
+
+AST_MATCHER_P(CXXForRangeStmt, hasRangeBeginEndStmt, ast_matchers::internal::Matcher<DeclStmt>,
+ InnerMatcher) {
+ const DeclStmt *const Stmt = Node.getBeginEndStmt();
+ return (Stmt != nullptr && InnerMatcher.matches(*Stmt, Finder, Builder));
+}
+
+AST_MATCHER(Stmt, isInsideOfRangeBeginEndStmt) {
+ return stmt(hasAncestor(cxxForRangeStmt(hasRangeBeginEndStmt(hasDescendant(equalsNode(&Node))))))
+ .matches(Node, Finder, Builder);
+}
+
+void ProBoundsArrayToPointerDecayCheck::registerMatchers(MatchFinder *Finder) {
+ if (!getLangOpts().CPlusPlus)
+ return;
+
+ // The only allowed array to pointer decay
+ // 1) just before array subscription
+ // 2) inside a range-for over an array
+ // 3) if it converts a string literal to a pointer
+ Finder->addMatcher(
+ implicitCastExpr(unless(hasParent(arraySubscriptExpr())),
+ unless(hasParent(explicitCastExpr())),
+ unless(isInsideOfRangeBeginEndStmt()),
+ 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 decay an array into a pointer; consider using gsl::array_view or an explicit cast instead");
+}
+
+} // namespace tidy
+} // namespace clang
+
Index: clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
===================================================================
--- clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
+++ clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
@@ -11,6 +11,7 @@
#include "../ClangTidyModule.h"
#include "../ClangTidyModuleRegistry.h"
#include "../misc/AssignOperatorSignatureCheck.h"
+#include "ProBoundsArrayToPointerDecayCheck.h"
#include "ProBoundsPointerArithmeticCheck.h"
#include "ProTypeConstCastCheck.h"
#include "ProTypeReinterpretCastCheck.h"
@@ -26,6 +27,8 @@
class CppCoreGuidelinesModule : public ClangTidyModule {
public:
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
+ CheckFactories.registerCheck<ProBoundsArrayToPointerDecayCheck>(
+ "cppcoreguidelines-pro-bounds-array-to-pointer-decay");
CheckFactories.registerCheck<ProBoundsPointerArithmeticCheck>(
"cppcoreguidelines-pro-bounds-pointer-arithmetic");
CheckFactories.registerCheck<ProTypeConstCastCheck>(
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
ProBoundsPointerArithmeticCheck.cpp
ProTypeConstCastCheck.cpp
ProTypeReinterpretCastCheck.cpp
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