[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

clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp

@@ -12,6 +12,7 @@
 #include "../ClangTidyModuleRegistry.h"
 #include "../misc/AssignOperatorSignatureCheck.h"
 #include "ProBoundsArrayToPointerDecayCheck.h"
+#include "ProBoundsConstantArrayIndexCheck.h"
 #include "ProBoundsPointerArithmeticCheck.h"
 #include "ProTypeConstCastCheck.h"
 #include "ProTypeCstyleCastCheck.h"
@@ -30,6 +31,8 @@ public:
   void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
     CheckFactories.registerCheck<ProBoundsArrayToPointerDecayCheck>(
         "cppcoreguidelines-pro-bounds-array-to-pointer-decay");
+    CheckFactories.registerCheck<ProBoundsConstantArrayIndexCheck>(
+        "cppcoreguidelines-pro-bounds-constant-array-index");
     CheckFactories.registerCheck<ProBoundsPointerArithmeticCheck>(
         "cppcoreguidelines-pro-bounds-pointer-arithmetic");
     CheckFactories.registerCheck<ProTypeConstCastCheck>(