Improve usability of adlc:
So far, expands can only use instructs that are specified further up in the .ad file.
This is because the check whether nodes used in the expand are also defined
is done during parsing.
Move this check to a later point to relax ordering constraints.
Add a row of additional, more verbose Syntax checks.
If MachNode::format() is called before constants are written to the
constants section, it can fail. Add a safer version of constant_offset
to avoid this.
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/