This is preparation for PPC64 integration: http://openjdk.java.net/jeps/175
This and following ppc64 changes will go into staging repository first and tested there: http://hg.openjdk.java.net/ppc-aix-port/stage/
A trampoline allows to encode a small branch in the code, even if there
is the chance that this branch can not reach all possible code locations.
If the relocation finds that a branch is too far for the instruction
in the code, it can patch it to jump to the trampoline where is
sufficient space for a far branch. Needed on PPC64.