arch: Fix all override related warnings.

Clang has started(?) reporting override related warnings, something gcc
apparently did before, but was disabled in the SConstruct. Rather than
disable the warnings in for clang as well, this change fixes the
warnings. A future change will re-enable the warnings for gcc.

Change-Id: I3cc79e45749b2ae0f9bebb1acadc56a3d3a942da
Reviewed-on: https://gem5-review.googlesource.com/9343
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>

alpha,arm,mips,power,riscv,sparc,x86,isa: De-specialize ExecContexts.

The ISA parser used to generate different copies of exec functions
for each exec context class a particular CPU wanted to use. That's
since been changed so that those functions take a pointer to the base
ExecContext, so the code which would generate those extra functions
can be removed, and some functions which used to be templated on an
ExecContext subclass can be untemplated, or minimally less templated.

Now that some functions aren't going to be instantiated multiple times
with different signatures, there are also opportunities to collapse
templates and make many instruction definitions simpler within the
parser. Since those changes will be less mechanical, they're left for
later changes and will probably be done in smaller increments.

Change-Id: I0015307bb02dfb9c60380b56d2a820f12169ebea
Reviewed-on: https://gem5-review.googlesource.com/5381
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

cpu: Simplify the rename interface and use RegId

With the hierarchical RegId there are a lot of functions that are
redundant now.

The idea behind the simplification is that instead of having the regId,
telling which kind of register read/write/rename/lookup/etc. and then
the function panic_if'ing if the regId is not of the appropriate type,
we provide an interface that decides what kind of register to read
depending on the register type of the given regId.

Change-Id: I7d52e9e21fc01205ae365d86921a4ceb67a57178
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
[ Fix RISCV build issues ]
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2702

arch, cpu: Architectural Register structural indexing

Replace the unified register mapping with a structure associating
a class and an index. It is now much easier to know which class of
register the index is referring to. Also, when adding a new class
there is no need to modify existing ones.

Change-Id: I55b3ac80763702aa2cd3ed2cbff0a75ef7620373
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
[ Fix RISCV build issues ]
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2700

arch: Use shared_ptr for all Faults

This patch takes quite a large step in transitioning from the ad-hoc
RefCountingPtr to the c++11 shared_ptr by adopting its use for all
Faults. There are no changes in behaviour, and the code modifications
are mostly just replacing "new" with "make_shared".

arch: teach ISA parser how to split code across files

This patch encompasses several interrelated and interdependent changes
to the ISA generation step. The end goal is to reduce the size of the
generated compilation units for instruction execution and decoding so
that batch compilation can proceed with all CPUs active without
exhausting physical memory.

The ISA parser (src/arch/isa_parser.py) has been improved so that it can
accept 'split [output_type];' directives at the top level of the grammar
and 'split(output_type)' python calls within 'exec {{ ... }}' blocks.
This has the effect of "splitting" the files into smaller compilation
units. I use air-quotes around "splitting" because the files themselves
are not split, but preprocessing directives are inserted to have the same
effect.

Architecturally, the ISA parser has had some changes in how it works.
In general, it emits code sooner. It doesn't generate per-CPU files,
and instead defers to the C preprocessor to create the duplicate copies
for each CPU type. Likewise there are more files emitted and the C
preprocessor does more substitution that used to be done by the ISA parser.

Finally, the build system (SCons) needs to be able to cope with a
dynamic list of source files coming out of the ISA parser. The changes
to the SCons{cript,truct} files support this. In broad strokes, the
targets requested on the command line are hidden from SCons until all
the build dependencies are determined, otherwise it would try, realize
it can't reach the goal, and terminate in failure. Since build steps
(i.e. running the ISA parser) must be taken to determine the file list,
several new build stages have been inserted at the very start of the
build. First, the build dependencies from the ISA parser will be emitted
to arch/$ISA/generated/inc.d, which is then read by a new SCons builder
to finalize the dependencies. (Once inc.d exists, the ISA parser will not
need to be run to complete this step.) Once the dependencies are known,
the 'Environments' are made by the makeEnv() function. This function used
to be called before the build began but now happens during the build.
It is easy to see that this step is quite slow; this is a known issue
and it's important to realize that it was already slow, but there was
no obvious cause to attribute it to since nothing was displayed to the
terminal. Since new steps that used to be performed serially are now in a
potentially-parallel build phase, the pathname handling in the SCons scripts
has been tightened up to deal with chdir() race conditions. In general,
pathnames are computed earlier and more likely to be stored, passed around,
and processed as absolute paths rather than relative paths. In the end,
some of these issues had to be fixed by inserting serializing dependencies
in the build.

Minor note:
For the null ISA, we just provide a dummy inc.d so SCons is never
compelled to try to generate it. While it seems slightly wrong to have
anything in src/arch/*/generated (i.e. a non-generated 'generated' file),
it's by far the simplest solution.

ISA parser: Use '_' instead of '.' to delimit type modifiers on operands.

By using an underscore, the "." is still available and can unambiguously be
used to refer to members of a structure if an operand is a structure, class,
etc. This change mostly just replaces the appropriate "."s with "_"s, but
there were also a few places where the ISA descriptions where handling the
extensions themselves and had their own regular expressions to update. The
regular expressions in the isa parser were updated as well. It also now
looks for one of the defined type extensions specifically after connecting "_"
where before it would look for any sequence of characters after a "."
following an operand name and try to use it as the extension. This helps to
disambiguate cases where a "_" may legitimately be part of an operand name but
not separate the name from the type suffix.

Because leaving the "_" and suffix on the variable name still leaves a valid
C++ identifier and all extensions need to be consistent in a given context, I
considered leaving them on as a breadcrumb that would show what the intended
type was for that operand. Unfortunately the operands can be referred to in
code templates, the Mem operand in particular, and since the exact type of Mem
can be different for different uses of the same template, that broke things.

add back in clobbered MIPS fix for g++ 4.2

go back and fix up MIPS copyright headers

Add in files from merge-bare-iron, get them compiling in FS and SE mode

String constant const-ness changes to placate g++ 4.2.
Also some bug fixes in MIPS ISA uncovered by g++ warnings
(Python string compares don't work in C++!).

mips import pt. 1

src/arch/mips/SConscript:
"mips import pt.1".

Minor cleanup of new snippet/subst code.

Started removing "CodeBlock" objects from the mips isa description.

Cleaned up include files and got rid of many using directives in header files.

Mips Code Cleanup:
Fix some author stuff and copyright dates
Take out full system code

src/arch/mips/isa/base.isa:
src/arch/mips/isa/bitfields.isa:
copyright info
src/arch/mips/isa/decoder.isa:
src/arch/mips/isa/formats/basic.isa:
src/arch/mips/isa/formats/branch.isa:
src/arch/mips/isa/formats/control.isa:
src/arch/mips/isa/formats/fp.isa:
src/arch/mips/isa/formats/int.isa:
src/arch/mips/isa/formats/mem.isa:
src/arch/mips/isa/formats/noop.isa:
src/arch/mips/isa/formats/tlbop.isa:
src/arch/mips/isa/formats/trap.isa:
src/arch/mips/isa/formats/unimp.isa:
src/arch/mips/isa/formats/unknown.isa:
src/arch/mips/isa/formats/util.isa:
src/arch/mips/isa/includes.isa:
src/arch/mips/isa/main.isa:
src/arch/mips/isa/operands.isa:
src/arch/mips/process.cc:
src/arch/mips/regfile/misc_regfile.hh:
src/arch/mips/stacktrace.hh:
copyright 2006
src/arch/mips/isa_traits.cc:
src/arch/mips/isa_traits.hh:
copyright 2006
take out full system
src/arch/mips/regfile/float_regfile.hh:
src/arch/mips/regfile/regfile.hh:
copyright 2006
use FloatRegVal
src/arch/mips/regfile/int_regfile.hh:
copyright 2006
move HI/LO to types.hh
src/arch/mips/types.hh:
copyright 2006

typedef FloatRegVal

-luxc1 fix
-noop templates
-trap disassembly

src/arch/mips/isa/decoder.isa:
luxc1 uses doubleword, not single
src/arch/mips/isa/formats/int.isa:
use new nop decode template
src/arch/mips/isa/formats/mem.isa:
Noop templates
src/arch/mips/isa/formats/noop.isa:
redo noop templates
src/arch/mips/isa/formats/trap.isa:
fix for trap disassembly

Authorship stuff

Merging in a month of changes

src/arch/isa_parser.py:
Sign extend bit if you read int reg that is greater than default size
src/arch/mips/SConscript:
src/arch/mips/faults.cc:
src/arch/mips/faults.hh:
src/arch/mips/isa/base.isa:
src/arch/mips/isa/bitfields.isa:
src/arch/mips/isa/decoder.isa:
src/arch/mips/isa/formats/basic.isa:
src/arch/mips/isa/formats/branch.isa:
src/arch/mips/isa/formats/formats.isa:
src/arch/mips/isa/formats/fp.isa:
src/arch/mips/isa/formats/int.isa:
src/arch/mips/isa/formats/mem.isa:
src/arch/mips/isa/formats/noop.isa:
src/arch/mips/isa/formats/tlbop.isa:
src/arch/mips/isa/formats/trap.isa:
src/arch/mips/isa/formats/unimp.isa:
src/arch/mips/isa/formats/unknown.isa:
src/arch/mips/isa/formats/util.isa:
src/arch/mips/isa/includes.isa:
src/arch/mips/isa/main.isa:
src/arch/mips/isa/operands.isa:
src/arch/mips/isa_traits.cc:
src/arch/mips/linux/process.cc:
src/arch/mips/linux/process.hh:
src/arch/mips/process.cc:
src/arch/mips/process.hh:
src/arch/mips/regfile/float_regfile.hh:
src/arch/mips/utility.hh:
1 month of changes!
src/arch/mips/isa/formats/control.isa:
control formats
src/arch/mips/isa/formats/mt.isa:
mips mt format
src/arch/mips/utility.cc:
utility functions

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.