misc: Adopt the gem5 namespace

Apply the gem5 namespace to the codebase.

Some anonymous namespaces could theoretically be removed,
but since this change's main goal was to keep conflicts
at a minimum, it was decided not to modify much the
general shape of the files.

A few missing comments of the form "// namespace X" that
occurred before the newly added "} // namespace gem5"
have been added for consistency.

std out should not be included in the gem5 namespace, so
they weren't.

ProtoMessage has not been included in the gem5 namespace,
since I'm not familiar with how proto works.

Regarding the SystemC files, although they belong to gem5,
they actually perform integration between gem5 and SystemC;
therefore, it deserved its own separate namespace.

Files that are automatically generated have been included
in the gem5 namespace.

The .isa files currently are limited to a single namespace.
This limitation should be later removed to make it easier
to accomodate a better API.

Regarding the files in util, gem5:: was prepended where
suitable. Notice that this patch was tested as much as
possible given that most of these were already not
previously compiling.

Change-Id: Ia53d404ec79c46edaa98f654e23bc3b0e179fe2d
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/46323
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>

util/systemc/systemc_within_gem5/systemc_sc_main/sc_main.cc

@@ -31,6 +31,8 @@
 
 #include "systemc/ext/systemc"
 
+using namespace gem5;
+
 class Printer : public sc_core::sc_module
 {
   public:

util/systemc/systemc_within_gem5/systemc_simple_object/feeder.cc

@@ -29,8 +29,8 @@
 #include "sim/sim_exit.hh"
 #include "systemc_simple_object/feeder.hh"
 
-Feeder::Feeder(const Gem5_FeederParams &params) :
-    SimObject(params), printer(params.printer), delay(params.delay),
+Feeder::Feeder(const gem5::Gem5_FeederParams &params) :
+    gem5::SimObject(params), printer(params.printer), delay(params.delay),
     strings(params.strings), index(0), event(this)
 {
     // Bind the printer objects "input" port to our sc_buffer. This will let
@@ -46,16 +46,16 @@ Feeder::Feeder(const Gem5_FeederParams &params) :
 void
 Feeder::startup()
 {
-    schedule(&event, curTick() + delay);
+    schedule(&event, gem5::curTick() + delay);
 }
 
 void
 Feeder::feed()
 {
     if (index >= strings.size())
-        exitSimLoop("Printed all the words.");
+        gem5::exitSimLoop("Printed all the words.");
     else
         buf.write(strings[index++].c_str());
 
-    schedule(&event, curTick() + delay);
+    schedule(&event, gem5::curTick() + delay);
 }

util/systemc/systemc_within_gem5/systemc_simple_object/feeder.hh

@@ -42,18 +42,21 @@
 #include "systemc/ext/channel/sc_buffer.hh"
 
 // This implementation (mostly) just uses standard gem5 mechanisms.
+namespace gem5
+{
 class Gem5_FeederParams;
+} // namespace gem5
 
-class Feeder : public SimObject
+class Feeder : public gem5::SimObject
 {
   public:
-    Feeder(const Gem5_FeederParams &params);
+    Feeder(const gem5::Gem5_FeederParams &params);
 
     void feed();
 
   private:
     Printer *printer;
-    Tick delay;
+    gem5::Tick delay;
     std::vector<std::string> strings;
     int index;
 
@@ -61,7 +64,7 @@ class Feeder : public SimObject
     // except to help interact with systemc objects/models.
     sc_core::sc_buffer<const char *> buf;
 
-    EventWrapper<Feeder, &Feeder::feed> event;
+    gem5::EventWrapper<Feeder, &Feeder::feed> event;
 
     void startup() override;
 };

util/systemc/systemc_within_gem5/systemc_simple_object/printer.cc

@@ -36,7 +36,7 @@
 // systemc object could accept those parameters however it likes, for instance
 // through its constructor or by assigning them to a member variable.
 Printer *
-SystemC_PrinterParams::create() const
+gem5::SystemC_PrinterParams::create() const
 {
     Printer *printer = new Printer(name.c_str());
     printer->prefix = prefix;

util/systemc/systemc_within_gem5/systemc_simple_object/printer.hh

@@ -71,7 +71,7 @@ class Printer : public sc_core::sc_module
         }
     }
 
-    statistics::Scalar numWords;
+    gem5::statistics::Scalar numWords;
 
     // Gem5 statistics should be set up during the "end_of_elabortion"
     // callback.