[clang-tidy] add check cppcoreguidelines-pro-bounds-constant-array-index

Summary:
This is http://reviews.llvm.org/D13746 but instead of including <array>,
a stub is provided.
This check flags all array subscriptions on static arrays and
std::arrays that either have a non-compile-time-constant index or are
out of bounds.

Dynamic accesses into arrays are difficult for both tools and humans to
validate as safe. array_view is a bounds-checked, safe type for
accessing arrays of data. at() is another alternative that ensures
single accesses are bounds-checked. If iterators are needed to access an
array, use the iterators from an array_view constructed over the array.

This rule is part of the "Bounds safety" profile of the C++ Core
Guidelines, see
https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#-bounds2-only-index-into-arrays-using-constant-expressions

Reviewers: alexfh, sbenza, bkramer, aaron.ballman

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D15030

llvm-svn: 255470

1 files changed, 40 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.h
new file mode 100644
index 00000000000..1caf28cc311
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.h
@@ -0,0 +1,40 @@
+//===--- ProBoundsConstantArrayIndexCheck.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_CONSTANT_ARRAY_INDEX_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_BOUNDS_CONSTANT_ARRAY_INDEX_H
+
+#include "../ClangTidy.h"
+#include "../utils/IncludeInserter.h"
+
+namespace clang {
+namespace tidy {
+
+/// This checks that all array subscriptions on static arrays and std::arrays
+/// have a constant index and are within bounds
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines-pro-bounds-constant-array-index.html
+class ProBoundsConstantArrayIndexCheck : public ClangTidyCheck {
+  const std::string GslHeader;
+  const IncludeSorter::IncludeStyle IncludeStyle;
+  std::unique_ptr<IncludeInserter> Inserter;
+
+public:
+  ProBoundsConstantArrayIndexCheck(StringRef Name, ClangTidyContext *Context);
+  void registerPPCallbacks(CompilerInstance &Compiler) override;
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_PRO_BOUNDS_CONSTANT_ARRAY_INDEX_H