[base] Fix integer check in CHECK/DCHECK macros

The current implementation failed when comparing an integral type to a
reference to an integral type of different signedness (see updated
unittest).
This CL fixes the checks to actually test the std::decay<T>::type,
i.e. with all references, const or volatile modifiers stripped.

R=jochen@chromium.org, ishell@chromium.org
TEST=unittests/LoggingTest.CompareWithReferenceType

Change-Id: Ib0ac077a91e0409ada7a80b68150cb98cbdd32f1
Reviewed-on: https://chromium-review.googlesource.com/502814Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45271}

src/base/logging.h

@@ -124,8 +124,10 @@ DEFINE_MAKE_CHECK_OP_STRING(void const*)
 template <typename Lhs, typename Rhs>
 struct is_signed_vs_unsigned {
   enum : bool {
-    value = std::is_integral<Lhs>::value && std::is_integral<Rhs>::value &&
-            std::is_signed<Lhs>::value && std::is_unsigned<Rhs>::value
+    value = std::is_integral<typename std::decay<Lhs>::type>::value &&
+            std::is_integral<typename std::decay<Rhs>::type>::value &&
+            std::is_signed<typename std::decay<Lhs>::type>::value &&
+            std::is_unsigned<typename std::decay<Rhs>::type>::value
   };
 };
 // Same thing, other way around: Lhs is unsigned, Rhs signed.
@@ -135,8 +137,10 @@ struct is_unsigned_vs_signed : public is_signed_vs_unsigned<Rhs, Lhs> {};
 // Specialize the compare functions for signed vs. unsigned comparisons.
 // std::enable_if ensures that this template is only instantiable if both Lhs
 // and Rhs are integral types, and their signedness does not match.
-#define MAKE_UNSIGNED(Type, value) \
-  static_cast<typename std::make_unsigned<Type>::type>(value)
+#define MAKE_UNSIGNED(Type, value)                                         \
+  static_cast<                                                             \
+      typename std::make_unsigned<typename std::decay<Type>::type>::type>( \
+      value)
 #define DEFINE_SIGNED_MISMATCH_COMP(CHECK, NAME, IMPL)                  \
   template <typename Lhs, typename Rhs>                                 \
   V8_INLINE typename std::enable_if<CHECK<Lhs, Rhs>::value, bool>::type \

test/unittests/base/logging-unittest.cc

@@ -63,11 +63,11 @@ TEST(LoggingTest, CompareAgainstStaticConstPointer) {
   CHECK_SUCCEED(GT, 0, v8::internal::Smi::kMinValue);
 }
 
-TEST(LoggingTest, CompareWithDifferentSignedness) {
 #define CHECK_BOTH(name, lhs, rhs) \
   CHECK_##name(lhs, rhs);          \
   DCHECK_##name(lhs, rhs)
 
+TEST(LoggingTest, CompareWithDifferentSignedness) {
   int32_t i32 = 10;
   uint32_t u32 = 20;
   int64_t i64 = 30;
@@ -82,5 +82,18 @@ TEST(LoggingTest, CompareWithDifferentSignedness) {
   CHECK_BOTH(IMPLIES, !u32, !i64);
 }
 
+TEST(LoggingTest, CompareWithReferenceType) {
+  int32_t i32 = 10;
+  uint32_t u32 = 20;
+  int64_t i64 = 30;
+  uint64_t u64 = 40;
+
+  // All these checks should compile (!) and succeed.
+  CHECK_BOTH(EQ, i32 + 10, *&u32);
+  CHECK_BOTH(LT, *&i32, u64);
+  CHECK_BOTH(IMPLIES, *&i32, i64);
+  CHECK_BOTH(IMPLIES, *&i32, u64);
+}
+
 }  // namespace base
 }  // namespace v8