The the code is being translated, we statically know offset of
Continuaton from its ActRec. Use this knowledge to emit data fetches
relative to ActRec rather than relative to Continuation loaded from
local 0.
This diff renames the Tracelet -> RegionDesc conversion mode to
"legacy" (since it's going away eventually) and changes "tracelet" to use the
new region selection mode. It attempts to select a region that will be the same
length as what Translator::analyze would come up with, using HhbcTranslator for
all of the type flow logic. It generates longer tracelets in some cases due to
more precise type information. Once this new mode is no longer a perf
regression it can become the new default, replacing all the code in
Translator::analyze and the "legacy" region mode. This version doesn't support
inlining or tracking of known Func*s; those will come in later diffs.
This diff creates IRTranslator, which creates and uses an
HhbcTranslator to implement the translate* methods. It can be used
independently of Translator or TranslatorX64 (it isn't yet but my next
region compiler diff uses it). I also moved a bunch of methods out of
inappropriate classes and changed the type guard/assert methods in
HhbcTranslator to use RegionDesc::Location instead of Transl::Location
and fixes a local tracking issue in translateRegion.
Having everybody and their uncle reading and writing fields out
of a.code and stubs.code was making assembler work hard. This replaces most
reads with accessors, and all writes with structured friends of
X64SAssembler.
mwilliams