[PATCH] D156624: [clang-tidy] Access checks not done classes derived of std::array

[Jorge Pinto Sousa via Phabricator via cfe-commits]

sousajo created this revision.
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sousajo requested review of this revision.
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Index accessing checks are not performed for derived classes of
of `std::array`, as only `std::array` itself and its aliases
seems to be checked.

      

This patch aims to extend it for derived classes such as:

  template<class T, size_t N>
  class DerivedArray : public std::array<T, N> {};


https://reviews.llvm.org/D156624

Files:
  clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
  clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-constant-array-index.cpp


Index: clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-constant-array-index.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-constant-array-index.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-bounds-constant-array-index.cpp
@@ -23,6 +23,9 @@
   return base + 3;
 }
 
+template<class T, size_t N>
+class DerivedArray : public std::array<T, N> {};
+
 void f(std::array<int, 10> a, int pos) {
   a [ pos / 2 /*comment*/] = 1;
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not use array subscript when the index is not an integer constant expression [cppcoreguidelines-pro-bounds-constant-array-index]
@@ -68,6 +71,51 @@
   m[const_index(6)] = 3; // OK, constant index and inside bounds
 }
 
+void f_derived(DerivedArray<int, 10> a, int pos) {
+  a [ pos / 2 /*comment*/] = 1;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not use array subscript when the index is not an integer constant expression [cppcoreguidelines-pro-bounds-constant-array-index]
+  int j = a[pos - 1];
+  // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: do not use array subscript when the index is not an integer constant expression
+
+  a.at(pos-1) = 2; // OK, at() instead of []
+  gsl::at(a, pos-1) = 2; // OK, gsl::at() instead of []
+
+  a[-1] = 3;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: std::array<> index -1 is negative [cppcoreguidelines-pro-bounds-constant-array-index]
+  a[10] = 4;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: std::array<> index 10 is past the end of the array (which contains 10 elements) [cppcoreguidelines-pro-bounds-constant-array-index]
+
+  a[const_index(7)] = 3;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: std::array<> index 10 is past the end of the array (which contains 10 elements)
+
+  a[0] = 3; // OK, constant index and inside bounds
+  a[1] = 3; // OK, constant index and inside bounds
+  a[9] = 3; // OK, constant index and inside bounds
+  a[const_index(6)] = 3; // OK, constant index and inside bounds
+
+  using MyArray = DerivedArray<int, 10>;
+  MyArray m{};
+  m [ pos / 2 /*comment*/] = 1;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not use array subscript when the index is not an integer constant expression [cppcoreguidelines-pro-bounds-constant-array-index]
+  int jj = m[pos - 1];
+  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: do not use array subscript when the index is not an integer constant expression
+
+  m.at(pos-1) = 2; // OK, at() instead of []
+  gsl::at(m, pos-1) = 2; // OK, gsl::at() instead of []
+  m[-1] = 3;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: std::array<> index -1 is negative [cppcoreguidelines-pro-bounds-constant-array-index]
+  m[10] = 4;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: std::array<> index 10 is past the end of the array (which contains 10 elements) [cppcoreguidelines-pro-bounds-constant-array-index]
+
+  m[const_index(7)] = 3;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: std::array<> index 10 is past the end of the array (which contains 10 elements)
+
+  m[0] = 3; // OK, constant index and inside bounds
+  m[1] = 3; // OK, constant index and inside bounds
+  m[9] = 3; // OK, constant index and inside bounds
+  m[const_index(6)] = 3; // OK, constant index and inside bounds
+}
+
 void g() {
   int a[10];
   for (int i = 0; i < 10; ++i) {
Index: clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
+++ clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
@@ -50,7 +50,8 @@
           hasOverloadedOperatorName("[]"),
           hasArgument(
               0, hasType(hasUnqualifiedDesugaredType(recordType(hasDeclaration(
-                     cxxRecordDecl(hasName("::std::array")).bind("type")))))),
+                     cxxRecordDecl(isSameOrDerivedFrom(hasName("::std::array")))
+                         .bind("type")))))),
           hasArgument(1, expr().bind("index")))
           .bind("expr"),
       this);


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