Decouple CpuFeatures from serializer state.
Traditionally, we cross compile a snapshot iff the serializer is enabled.
This will change in the future.
Changes:
- CpuFeatures probing is done once per process, depending on whether we
cross compile.
- CpuFeatures are consolidated into the platform-independent assembler.h
as much as possible.
- FLAG_enable_<feature> will only be checked at probing time (already the
case for ARM).
- The serializer state is cached by the MacroAssembler.
- PlatformFeatureScope is no longer necessary.
- CPUFeature enum values no longer map to CPUID bit fields.
R=svenpanne@chromium.org
Review URL: https://codereview.chromium.org/
285233010
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21347
ce2b1a6d-e550-0410-aec6-
3dcde31c8c00