Do I need to extract a source tar file for each pass in LFS, or does creating a seperate named "build" folder suffice (like "build", "build2")?

There's a handful of programs like GCC that not only require two different passes when setting up LFS, but as is the case with GCC, it is also used for Libstdc++. When going thru this setting up for LFS, what is expected me of to do? The directions are somewhat vague on whether I should extract the source tar file into a different named folder for each pass, or if I should create a separate build folder inside the source folder for each pass (like "build", "build2")? Also what would happen if I used the same build directory that was used in the original pass 1 but obviously configured differently for the second pass? Would there be any conflicts?