[clang-tidy] Add new 'readability-uppercase-literal-suffix' check (CERT DCL16-C, MISRA C:2012, 7.3, MISRA C++:2008, 2-13-4)

Summary:
Detects when the integral literal or floating point (decimal or hexadecimal)
literal has non-uppercase suffix, and suggests to make the suffix uppercase,
with fix-it.

All valid combinations of suffixes are supported.

```
  auto x = 1;  // OK, no suffix.

  auto x = 1u; // warning: integer literal suffix 'u' is not upper-case

  auto x = 1U; // OK, suffix is uppercase.

  ...
```

References:
* [[ https://wiki.sei.cmu.edu/confluence/pages/viewpage.action?pageId=87152241 | CERT DCL16-C ]]
* MISRA C:2012, 7.3 - The lowercase character "l" shall not be used in a literal suffix
* MISRA C++:2008, 2-13-4 - Literal suffixes shall be upper case

Reviewers: JonasToth, aaron.ballman, alexfh, hokein, xazax.hun

Reviewed By: aaron.ballman

Subscribers: Eugene.Zelenko, mgorny, rnkovacs, cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D52670

llvm-svn: 344755

1 files changed, 130 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/readability-uppercase-literal-suffix-integer-custom-list.cpp b/clang-tools-extra/test/clang-tidy/readability-uppercase-literal-suffix-integer-custom-list.cpp
new file mode 100644
index 00000000000..ff67a336b25
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/readability-uppercase-literal-suffix-integer-custom-list.cpp
@@ -0,0 +1,130 @@
+// RUN: %check_clang_tidy %s readability-uppercase-literal-suffix %t -- -config="{CheckOptions: [{key: readability-uppercase-literal-suffix.NewSuffixes, value: 'L;uL'}]}" -- -I %S
+// RUN: grep -Ev "// *[A-Z-]+:" %s > %t.cpp
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -fix -config="{CheckOptions: [{key: readability-uppercase-literal-suffix.NewSuffixes, value: 'L;uL'}]}" -- -I %S
+// RUN: clang-tidy %t.cpp -checks='-*,readability-uppercase-literal-suffix' -warnings-as-errors='-*,readability-uppercase-literal-suffix' -config="{CheckOptions: [{key: readability-uppercase-literal-suffix.NewSuffixes, value: 'L;uL'}]}" -- -I %S
+
+#include "readability-uppercase-literal-suffix.h"
+
+void integer_suffix() {
+  // Unsigned
+
+  static constexpr auto v3 = 1u; // OK.
+  static_assert(is_same<decltype(v3), const unsigned int>::value, "");
+  static_assert(v3 == 1, "");
+
+  static constexpr auto v4 = 1U; // OK.
+  static_assert(is_same<decltype(v4), const unsigned int>::value, "");
+  static_assert(v4 == 1, "");
+
+  // Long
+
+  static constexpr auto v5 = 1l;
+  // CHECK-MESSAGES: :[[@LINE-1]]:30: warning: integer literal has suffix 'l', which is not uppercase
+  // CHECK-MESSAGES-NEXT: static constexpr auto v5 = 1l;
+  // CHECK-MESSAGES-NEXT: ^~
+  // CHECK-MESSAGES-NEXT: {{^ *}}L{{$}}
+  // CHECK-FIXES: static constexpr auto v5 = 1L;
+  static_assert(is_same<decltype(v5), const long>::value, "");
+  static_assert(v5 == 1, "");
+
+  static constexpr auto v6 = 1L; // OK.
+  static_assert(is_same<decltype(v6), const long>::value, "");
+  static_assert(v6 == 1, "");
+
+  // Long Long
+
+  static constexpr auto v7 = 1ll; // OK.
+  static_assert(is_same<decltype(v7), const long long>::value, "");
+  static_assert(v7 == 1, "");
+
+  static constexpr auto v8 = 1LL; // OK.
+  static_assert(is_same<decltype(v8), const long long>::value, "");
+  static_assert(v8 == 1, "");
+
+  // Unsigned Long
+
+  static constexpr auto v9 = 1ul;
+  // CHECK-MESSAGES: :[[@LINE-1]]:30: warning: integer literal has suffix 'ul', which is not uppercase
+  // CHECK-MESSAGES-NEXT: static constexpr auto v9 = 1ul;
+  // CHECK-MESSAGES-NEXT: ^~~
+  // CHECK-MESSAGES-NEXT: {{^ *}}uL{{$}}
+  // CHECK-FIXES: static constexpr auto v9 = 1uL;
+  static_assert(is_same<decltype(v9), const unsigned long>::value, "");
+  static_assert(v9 == 1, "");
+
+  static constexpr auto v10 = 1uL; // OK.
+  static_assert(is_same<decltype(v10), const unsigned long>::value, "");
+  static_assert(v10 == 1, "");
+
+  static constexpr auto v11 = 1Ul;
+  // CHECK-MESSAGES: :[[@LINE-1]]:31: warning: integer literal has suffix 'Ul', which is not uppercase
+  // CHECK-MESSAGES-NEXT: static constexpr auto v11 = 1Ul;
+  // CHECK-MESSAGES-NEXT: ^~~
+  // CHECK-MESSAGES-NEXT: {{^ *}}uL{{$}}
+  // CHECK-FIXES: static constexpr auto v11 = 1uL;
+  static_assert(is_same<decltype(v11), const unsigned long>::value, "");
+  static_assert(v11 == 1, "");
+
+  static constexpr auto v12 = 1UL; // OK.
+  // CHECK-MESSAGES: :[[@LINE-1]]:31: warning: integer literal has suffix 'UL', which is not uppercase
+  // CHECK-MESSAGES-NEXT: static constexpr auto v12 = 1UL;
+  // CHECK-MESSAGES-NEXT: ^~~
+  // CHECK-MESSAGES-NEXT: {{^ *}}uL{{$}}
+  // CHECK-FIXES: static constexpr auto v12 = 1uL;
+  static_assert(is_same<decltype(v12), const unsigned long>::value, "");
+  static_assert(v12 == 1, "");
+
+  // Long Unsigned
+
+  static constexpr auto v13 = 1lu; // OK.
+  static_assert(is_same<decltype(v13), const unsigned long>::value, "");
+  static_assert(v13 == 1, "");
+
+  static constexpr auto v14 = 1Lu; // OK.
+  static_assert(is_same<decltype(v14), const unsigned long>::value, "");
+  static_assert(v14 == 1, "");
+
+  static constexpr auto v15 = 1lU; // OK.
+  static_assert(is_same<decltype(v15), const unsigned long>::value, "");
+  static_assert(v15 == 1, "");
+
+  static constexpr auto v16 = 1LU; // OK.
+  static_assert(is_same<decltype(v16), const unsigned long>::value, "");
+  static_assert(v16 == 1, "");
+
+  // Unsigned Long Long
+
+  static constexpr auto v17 = 1ull; // OK.
+  static_assert(is_same<decltype(v17), const unsigned long long>::value, "");
+  static_assert(v17 == 1, "");
+
+  static constexpr auto v18 = 1uLL; // OK.
+  static_assert(is_same<decltype(v18), const unsigned long long>::value, "");
+  static_assert(v18 == 1, "");
+
+  static constexpr auto v19 = 1Ull; // OK.
+  static_assert(is_same<decltype(v19), const unsigned long long>::value, "");
+  static_assert(v19 == 1, "");
+
+  static constexpr auto v20 = 1ULL; // OK.
+  static_assert(is_same<decltype(v20), const unsigned long long>::value, "");
+  static_assert(v20 == 1, "");
+
+  // Long Long Unsigned
+
+  static constexpr auto v21 = 1llu; // OK.
+  static_assert(is_same<decltype(v21), const unsigned long long>::value, "");
+  static_assert(v21 == 1, "");
+
+  static constexpr auto v22 = 1LLu; // OK.
+  static_assert(is_same<decltype(v22), const unsigned long long>::value, "");
+  static_assert(v22 == 1, "");
+
+  static constexpr auto v23 = 1llU; // OK.
+  static_assert(is_same<decltype(v23), const unsigned long long>::value, "");
+  static_assert(v23 == 1, "");
+
+  static constexpr auto v24 = 1LLU; // OK.
+  static_assert(is_same<decltype(v24), const unsigned long long>::value, "");
+  static_assert(v24 == 1, "");
+}