[clang-tidy] Add new check cppcoreguidelines-pro-bounds-array-to-pointer-decay
Summary:
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
Reviewers: alexfh, sbenza, bkramer, aaron.ballman
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D13640
llvm-svn: 251358
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt b/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
index b2c2bdf..506a907 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt
@@ -2,6 +2,7 @@
add_clang_library(clangTidyCppCoreGuidelinesModule
CppCoreGuidelinesTidyModule.cpp
+ ProBoundsArrayToPointerDecayCheck.cpp
ProBoundsPointerArithmeticCheck.cpp
ProTypeConstCastCheck.cpp
ProTypeReinterpretCastCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
index 9929d66..d77954b 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp
+++ b/clang-tools-extra/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>(
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp
new file mode 100644
index 0000000..514289d
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp
@@ -0,0 +1,60 @@
+//===--- 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
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.h
new file mode 100644
index 0000000..21a9572
--- /dev/null
+++ b/clang-tools-extra/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
+