base: Fix enums checkpointing

Creating an extra version of string to number converters (__to_number)
in base/str.hh; it will be used by enums only when unserializing
them. The reason not to have a single helper for both enums and
integers is that std::numeric_limits trait is not specialized for enums.
We fix this by using the std::underlying_type trait.

Change-Id: I819e35c0df8c094de7b7a6390152964fa47d513d
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Ciro Santilli <ciro.santilli@arm.com>
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/16382
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

base: Make it possible to convert strings to enums

The __to_number helper function defined in base/str.hh is used by
unserializing code. Its purpose is to convert a string into an
integral/floating point number. Since enums underlying type can only be
an integer type, it makes sense to extend the helper function for enums
as well. In this way it will be possible to unserialize Enums and
containers of Enums without the need of casting.

Change-Id: I74069cc4c04ec8b5eb80939acea7ab18fb366dd4
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Ciro Santilli <ciro.santilli@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15336
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

base: Don't let exceptions leak from the to_number utility function.

This function catches a couple types of exceptions the functions it
calls might throw, but if one that it doesn't catch is thrown, then
it will propogate that exception to its own callers, and not initialize
the value it was asked to convert.

This might be considered desirable behavior since it lets errors
propogate and avoids handling them in code that might not know the
context of when it's called. On the other hand, it upsets g++ since it
thinks that there might be an uninitialized value used elsewhere, even
though that value will only be uninitialized if an exception is
propogating, and the code that would use it is after a point where that
exception would have been caught and execution would have resumed.

To satisfy g++ and to also avoid silently hiding errors, this change
adds a catch all which will panic if an unexpected exception is raised.

Change-Id: Ie94dcef3a50f7902566328a3fa2eac59b3cf9aad
Reviewed-on: https://gem5-review.googlesource.com/c/14399
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

base: Clean up redundant string functions and use C++11

This patch does a bit of housekeeping on the string helper functions
and relies on the C++11 standard library where possible. It also does
away with our custom string hash as an implementation is already part
of the standard library.

str: add an overloaded startswith() utility method
for various string types and use it in a few places.

includes: sort all includes

Updated Authors from bk prs info

New directory structure:
- simulator source now in 'src' subdirectory
- imported files from 'ext' repository
- support building in arbitrary places, including
outside of the source tree. See comment at top
of SConstruct file for more details.
Regression tests are temporarily disabled; that
syetem needs more extensive revisions.

SConstruct:
Update for new directory structure.
Modify to support build trees that are not subdirectories
of the source tree. See comment at top of file for
more details.
Regression tests are temporarily disabled.
src/arch/SConscript:
src/arch/isa_parser.py:
src/python/SConscript:
Update for new directory structure.