Remove remaining base dependencies from base/numerics

base/numerics/safe_conversions.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_NUMERICS_SAFE_CONVERSIONS_H_
 #define BASE_NUMERICS_SAFE_CONVERSIONS_H_
 
 #include <stddef.h>
 
+#include <cassert>
 #include <limits>
 #include <type_traits>
 
-#include "base/logging.h"
 #include "base/numerics/safe_conversions_impl.h"
 
 namespace base {
 
 // Convenience function that returns true if the supplied value is in range
 // for the destination type.
 template <typename Dst, typename Src>
 constexpr bool IsValueInRangeForNumericType(Src value) {
   return internal::DstRangeRelationToSrcRange<Dst>(value) ==
          internal::RANGE_VALID;
@@ skipping 10 matching lines @@
 }
 
 template <typename T>
 constexpr typename std::enable_if<!std::numeric_limits<T>::is_signed,
                                   bool>::type IsValueNegative(T) {
   static_assert(std::numeric_limits<T>::is_specialized,
                 "Argument must be numeric.");
   return false;
 }
 
-// Just fires a CHECK(false). Used for numeric boundary errors.
+// Forces a crash, like a CHECK(false). Used for numeric boundary errors.
 struct CheckOnFailure {
   template <typename T>
   static T HandleFailure() {
-    CHECK(false);
+#if defined(__GNUC__) || defined(__clang__)
+    __builtin_trap();
+#else
+    ((void)(*(volatile char*)0 = 0));

[Tom Sepez, 2016/11/22 18:17:31]

I thought we had an issue with some compiler pulling these out due to "undefined
behavior".  But we do the same in partitionAlloc.  We have EXPECT_DEATH tests
for these?

[jschuh, 2016/11/22 18:27:52]

This is exactly what base/logging.h uses for a CHECK in release builds. Maybe
GCC or clang would optimize it out as undefined behavior, but those are using an
explicit trap intrinsic.

+#endif
     return T();
   }
 };
 
 // checked_cast<> is analogous to static_cast<> for numeric types,
 // except that it CHECKs that the specified numeric conversion will not
 // overflow or underflow. NaN source will always trigger a CHECK.
 template <typename Dst,
           class CheckHandler = CheckOnFailure,
           typename Src>
 constexpr Dst checked_cast(Src value) {
   // This throws a compile-time error on evaluating the constexpr if it can be
   // determined at compile-time as failing, otherwise it will CHECK at runtime.
   return IsValueInRangeForNumericType<Dst>(value)
              ? static_cast<Dst>(value)
              : CheckHandler::template HandleFailure<Dst>();
 }
 
 // HandleNaN will return 0 in this case.
 struct SaturatedCastNaNBehaviorReturnZero {
   template <typename T>
   static constexpr T HandleFailure() {
     return T();
   }
 };
 
 namespace internal {
 // This wrapper is used for C++11 constexpr support by avoiding the declaration
 // of local variables in the saturated_cast template function.
+// TODO(jschuh): convert this back to a switch once we support C++14.
 template <typename Dst, class NaNHandler, typename Src>
 constexpr Dst saturated_cast_impl(const Src value,
                                   const RangeConstraint constraint) {
   return constraint == RANGE_VALID
              ? static_cast<Dst>(value)
              : (constraint == RANGE_UNDERFLOW
                     ? std::numeric_limits<Dst>::min()
                     : (constraint == RANGE_OVERFLOW
                            ? std::numeric_limits<Dst>::max()
                            : (constraint == RANGE_INVALID
                                   ? NaNHandler::template HandleFailure<Dst>()
-                                  : (NOTREACHED(), static_cast<Dst>(value)))));
+                                  : (assert(false), static_cast<Dst>(value)))));
 }
 }  // namespace internal
 
 // saturated_cast<> is analogous to static_cast<> for numeric types, except
 // that the specified numeric conversion will saturate rather than overflow or
 // underflow. NaN assignment to an integral will defer the behavior to a
 // specified class. By default, it will return 0.
 template <typename Dst,
           class NaNHandler = SaturatedCastNaNBehaviorReturnZero,
           typename Src>
@@ skipping 62 matching lines @@
  private:
   const T value_;
 };
 
 // Explicitly make a shorter size_t typedef for convenience.
 typedef StrictNumeric<size_t> SizeT;
 
 }  // namespace base
 
 #endif  // BASE_NUMERICS_SAFE_CONVERSIONS_H_