There is a fix[1] in binutils 2.30 that we want for Chromium. Version 2.29 and earlier has a performance problem with objcopy (and possibly other tools) where they are O(n^2) in number of sections in the object file. Since Chromium is compiled with -ffunction-section there can be many hundreds or thousands of sections per cc file instead of just one. 

In some jumbo builds, those hundreds or hundreds can become tens of thousands and then an objcopy that should have been more or less instant can take more than 5 minutes.

None of the official configurations experience the most extreme slowdown which is why it's not been urgent but at some time it should be switched to (it was released at the beginning of the year). Unless the project has moved to llvm objcopy but if that is happening I have not noticed.

[1]: https://sourceware.org/ml/binutils/2018-01/msg00197.html