This diff adds a relativeOffsets option to Disasm, which will print
code addresses as relative offsets from the beginning of the tracelet instead
of absolute addresses. This format makes it much easier to compare the relative
sizes of the instructions selected by the two jits. I also changed the runtime
option to be a double instead of a bool, which is used as the cutoff ratio for
which tracelets to print. Setting it to 1 will print tracelets where the ir
made larger code than tx64, setting it to 2 will print tracelets where the ir's
code is at least twice as big as tx64's, etc...
Adds debug symbols on calls into the runtime so we can better
understand/compare the helpers being called when we use DumpIR or
JitCompareHHIR.
I used the GNU backtrace_symbols() facility to do the translation of
address->symbol, since it seemed like the easiest route to this
functionality.
This change is mostly for FB internal organizational reasons.
Building is not effected beyond the fact that the target now
lands in hphp/hhvm/hhvm rather than src/hhvm/hhvm.
bsimmers