cpu,sim: Get rid of a bunch of conditional compilation for PCEvents.

These can now be built without referring to anything in ThreadContext
and so can be built even with the NULL ISA. This means the pcEventQueue
can be unconditionally built into the System class. Even though the
pcEventQueue is going away, this still makes it possible for System to
be a PCEventScope unconditionally.

Change-Id: Ia342bb7972b1b5ce95033176d72af4bfa343560f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22104
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/cpu/SConscript

@@ -72,6 +72,8 @@ CompoundFlag('ExecNoTicks', [ 'ExecEnable', 'ExecOpClass', 'ExecThread',
     'ExecEffAddr', 'ExecResult', 'ExecMicro', 'ExecMacro', 'ExecFaulting',
     'ExecUser', 'ExecKernel' ])
 
+Source('pc_event.cc')
+
 if env['TARGET_ISA'] == 'null':
     SimObject('IntrControl.py')
     Source('intr_control_noisa.cc')
@@ -99,7 +101,6 @@ Source('func_unit.cc')
 Source('inteltrace.cc')
 Source('intr_control.cc')
 Source('nativetrace.cc')
-Source('pc_event.cc')
 Source('profile.cc')
 Source('quiesce_event.cc')
 Source('reg_class.cc')

src/cpu/pc_event.cc

@@ -37,8 +37,6 @@
 
 #include "base/debug.hh"
 #include "base/trace.hh"
-#include "cpu/base.hh"
-#include "cpu/thread_context.hh"
 #include "debug/PCEvent.hh"
 #include "sim/core.hh"
 #include "sim/system.hh"

src/sim/system.cc

@@ -292,7 +292,6 @@ System::registerThreadContext(ThreadContext *tc, ContextID assigned)
     return id;
 }
 
-#if THE_ISA != NULL_ISA
 bool
 System::schedule(PCEvent *event)
 {
@@ -304,7 +303,6 @@ System::remove(PCEvent *event)
 {
     return pcEventQueue.remove(event);
 }
-#endif
 
 int
 System::numRunningContexts()

src/sim/system.hh

@@ -57,6 +57,7 @@
 #include "base/loader/symtab.hh"
 #include "base/statistics.hh"
 #include "config/the_isa.hh"
+#include "cpu/pc_event.hh"
 #include "enums/MemoryMode.hh"
 #include "mem/mem_master.hh"
 #include "mem/physical.hh"
@@ -68,25 +69,12 @@
 #include "sim/se_signal.hh"
 #include "sim/sim_object.hh"
 
-/**
- * To avoid linking errors with LTO, only include the header if we
- * actually have the definition.
- */
-#if THE_ISA != NULL_ISA
-#include "cpu/pc_event.hh"
-#else
-class PCEvent;
-#endif
-
 class BaseRemoteGDB;
 class KvmVM;
 class ObjectFile;
 class ThreadContext;
 
-class System : public SimObject
-#if THE_ISA != NULL_ISA
-               , public PCEventScope
-#endif
+class System : public SimObject, public PCEventScope
 {
   private:
 
@@ -198,19 +186,15 @@ class System : public SimObject
      */
     unsigned int cacheLineSize() const { return _cacheLineSize; }
 
-#if THE_ISA != NULL_ISA
     PCEventQueue pcEventQueue;
-#endif
 
     std::vector<ThreadContext *> threadContexts;
     const bool multiThread;
 
     using SimObject::schedule;
 
-#if THE_ISA != NULL_ISA
     bool schedule(PCEvent *event) override;
     bool remove(PCEvent *event) override;
-#endif
 
     ThreadContext *getThreadContext(ContextID tid) const
     {
@@ -502,13 +486,11 @@ class System : public SimObject
     {
         Addr addr M5_VAR_USED = 0; // initialize only to avoid compiler warning
 
-#if THE_ISA != NULL_ISA
         if (symtab->findAddress(lbl, addr)) {
             T *ev = new T(this, desc, fixFuncEventAddr(addr),
                           std::forward<Args>(args)...);
             return ev;
         }
-#endif
 
         return NULL;
     }