- const FunctionIndexEntry* base = this->functions_index.data();
- int i = 0;
- int j = this->functions_index.size() - 1;
- while (j >= i) {
- int k = i + ((j - i) / 2);
-
- /* In most of the search, we do not dereference the base[k].function.
- * This way the memory accesses are located in the base[k] array. */
- if (ip < base[k].low_pc)
- j = k - 1;
- else if (k < j && ip >= base[k + 1].low_pc)
- i = k + 1;
-
- /* At this point, the search is over.
- * Either we have found the correct function or we do not know
- * any function corresponding to this instruction address.
- * Only at the point do we dereference the function pointer. */
- else if ((std::uint64_t)ip < base[k].function->range.end())
- return base[k].function;
- else
- return nullptr;
- }
- return nullptr;
+ auto pos = std::lower_bound(this->functions_index.rbegin(), this->functions_index.rend(), ip,
+ [](auto const& func, auto const* addr) { return func.low_pc > addr; });
+
+ /* At this point, the search is over.
+ * Either we have found the correct function or we do not know
+ * any function corresponding to this instruction address.
+ * Only at the point do we dereference the function pointer. */
+ return (pos != this->functions_index.rend() && reinterpret_cast<std::uint64_t>(ip) < pos->function->range.end())
+ ? pos->function
+ : nullptr;