arch,cpu,dev,sim,mem: Collect System thread elements into a subclass.

The System class has a few different arrays of values which each
correspond to a thread of execution based on their position. This
change collects them together into a single class to make managing them
easier and less error prone. It also collects methods for manipulating
those threads as an API for that class.

This class acts as a collection point for thread based state which the
System class can look into to get at all its state. It also acts as an
interface for interacting with threads for other classes. This forces
external consumers to use the API instead of accessing the individual
arrays which improves consistency.

Change-Id: Idc4575c5a0b56fe75f5c497809ad91c22bfe26cc
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/25144
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>

src/cpu/base.hh

@@ -54,6 +54,7 @@
 #include "arch/isa_traits.hh"
 #include "arch/microcode_rom.hh"
 #include "base/statistics.hh"
+#include "mem/port_proxy.hh"
 #include "sim/clocked_object.hh"
 #include "sim/eventq.hh"
 #include "sim/full_system.hh"

src/cpu/intr_control.cc

@@ -47,7 +47,7 @@ void
 IntrControl::post(int cpu_id, int int_num, int index)
 {
     DPRINTF(IntrControl, "post  %d:%d (cpu %d)\n", int_num, index, cpu_id);
-    ThreadContext *tc = sys->getThreadContext(cpu_id);
+    auto *tc = sys->threads[cpu_id];
     tc->getCpuPtr()->postInterrupt(tc->threadId(), int_num, index);
 }
 
@@ -55,7 +55,7 @@ void
 IntrControl::clear(int cpu_id, int int_num, int index)
 {
     DPRINTF(IntrControl, "clear %d:%d (cpu %d)\n", int_num, index, cpu_id);
-    ThreadContext *tc = sys->getThreadContext(cpu_id);
+    auto *tc = sys->threads[cpu_id];
     tc->getCpuPtr()->clearInterrupt(tc->threadId(), int_num, index);
 }
 
@@ -63,7 +63,7 @@ void
 IntrControl::clearAll(int cpu_id)
 {
     DPRINTF(IntrControl, "Clear all pending interrupts for CPU %d\n", cpu_id);
-    ThreadContext *tc = sys->getThreadContext(cpu_id);
+    auto *tc = sys->threads[cpu_id];
     tc->getCpuPtr()->clearInterrupts(tc->threadId());
 }
 
@@ -71,7 +71,7 @@ bool
 IntrControl::havePosted(int cpu_id) const
 {
     DPRINTF(IntrControl, "Check pending interrupts for CPU %d\n", cpu_id);
-    ThreadContext *tc = sys->getThreadContext(cpu_id);
+    auto *tc = sys->threads[cpu_id];
     return tc->getCpuPtr()->checkInterrupts(tc);
 }
 

src/cpu/kvm/vm.cc

@@ -539,7 +539,7 @@ KvmVM::contextIdToVCpuId(ContextID ctx) const
 {
     assert(system != nullptr);
     return dynamic_cast<BaseKvmCPU*>
-        (system->getThreadContext(ctx)->getCpuPtr())->getVCpuID();
+        (system->threads[ctx]->getCpuPtr())->getVCpuID();
 }
 
 int

src/cpu/o3/cpu.cc

@@ -757,7 +757,7 @@ FullO3CPU<Impl>::insertThread(ThreadID tid)
     // and not in the ThreadContext.
     ThreadContext *src_tc;
     if (FullSystem)
-        src_tc = system->threadContexts[tid];
+        src_tc = system->threads[tid];
     else
         src_tc = tcBase(tid);