cpu: Make getIsaPtr return a BaseISA pointer.

This isolates the architecture specific ISA types a little bit, and
means that ThreadContexts don't *have* to find an architecture specific
class to return, even if they don't naturally have one lying around.

Change-Id: Ide10b5d945ec6076947b2ccdea87c86e96e40857
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/25008
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>

src/arch/arm/fastmodel/iris/thread_context.hh

@@ -209,7 +209,7 @@ class ThreadContext : public ::ThreadContext
 
     System *getSystemPtr() override { return _cpu->system; }
 
-    ArmISA::ISA *
+    BaseISA *
     getIsaPtr() override
     {
         panic("%s not implemented.", __FUNCTION__);

src/cpu/checker/thread_context.hh

@@ -142,7 +142,7 @@ class CheckerThreadContext : public ThreadContext
         return checkerCPU;
     }
 
-    TheISA::ISA *getIsaPtr() override { return actualTC->getIsaPtr(); }
+    BaseISA *getIsaPtr() override { return actualTC->getIsaPtr(); }
 
     TheISA::Decoder *
     getDecoderPtr() override

src/cpu/o3/thread_context.hh

@@ -113,7 +113,7 @@ class O3ThreadContext : public ThreadContext
 
     CheckerCPU *getCheckerCpuPtr() override { return NULL; }
 
-    TheISA::ISA *
+    BaseISA *
     getIsaPtr() override
     {
         return cpu->isa[thread->threadId()];

src/cpu/simple_thread.hh

@@ -230,7 +230,7 @@ class SimpleThread : public ThreadState, public ThreadContext
 
     CheckerCPU *getCheckerCpuPtr() override { return NULL; }
 
-    TheISA::ISA *getIsaPtr() override { return isa; }
+    BaseISA *getIsaPtr() override { return isa; }
 
     TheISA::Decoder *getDecoderPtr() override { return &decoder; }
 

src/cpu/thread_context.hh

@@ -47,6 +47,7 @@
 #include <iostream>
 #include <string>
 
+#include "arch/generic/isa.hh"
 #include "arch/registers.hh"
 #include "arch/types.hh"
 #include "base/types.hh"
@@ -141,7 +142,7 @@ class ThreadContext : public PCEventScope
 
     virtual CheckerCPU *getCheckerCpuPtr() = 0;
 
-    virtual TheISA::ISA *getIsaPtr() = 0;
+    virtual BaseISA *getIsaPtr() = 0;
 
     virtual TheISA::Decoder *getDecoderPtr() = 0;