MEM: Make port proxies use references rather than pointers

This patch is adding a clearer design intent to all objects that would
not be complete without a port proxy by making the proxies members
rathen than dynamically allocated. In essence, if NULL would not be a
valid value for the proxy, then we avoid using a pointer to make this
clear.

The same approach is used for the methods using these proxies, such as
loadSections, that now use references rather than pointers to better
reflect the fact that NULL would not be an acceptable value (in fact
the code would break and that is how this patch started out).

Overall the concept of "using a reference to express unconditional
composition where a NULL pointer is never valid" could be done on a
much broader scale throughout the code base, but for now it is only
done in the locations affected by the proxies.

2 files changed, 10 insertions, 12 deletions

diff --git a/src/arch/alpha/linux/system.cc b/src/arch/alpha/linux/system.cc
index 6f3cf6b32..e42553b63 100644
--- a/src/arch/alpha/linux/system.cc
+++ b/src/arch/alpha/linux/system.cc
@@ -88,9 +88,9 @@ LinuxAlphaSystem::initState()
      * Since we aren't using a bootloader, we have to copy the
      * kernel arguments directly into the kernel's memory.
      */
-    virtProxy->writeBlob(CommandLine(),
-                         (uint8_t*)params()->boot_osflags.c_str(),
-                         params()->boot_osflags.length()+1);
+    virtProxy.writeBlob(CommandLine(),
+                        (uint8_t*)params()->boot_osflags.c_str(),
+                        params()->boot_osflags.length()+1);
 
     /**
      * find the address of the est_cycle_freq variable and insert it
@@ -98,8 +98,8 @@ LinuxAlphaSystem::initState()
      * calculated it by using the PIT, RTC, etc.
      */
     if (kernelSymtab->findAddress("est_cycle_freq", addr))
-        virtProxy->write(addr, (uint64_t)(SimClock::Frequency /
-                                          params()->boot_cpu_frequency));
+        virtProxy.write(addr, (uint64_t)(SimClock::Frequency /
+                                         params()->boot_cpu_frequency));
 
 
     /**
@@ -109,7 +109,7 @@ LinuxAlphaSystem::initState()
      * 255 ASNs.
      */
     if (kernelSymtab->findAddress("dp264_mv", addr))
-        virtProxy->write(addr + 0x18, LittleEndianGuest::htog((uint32_t)127));
+        virtProxy.write(addr + 0x18, LittleEndianGuest::htog((uint32_t)127));
     else
         panic("could not find dp264_mv\n");
 
@@ -176,10 +176,8 @@ LinuxAlphaSystem::setDelayLoop(ThreadContext *tc)
     if (kernelSymtab->findAddress("loops_per_jiffy", addr)) {
         Tick cpuFreq = tc->getCpuPtr()->frequency();
         assert(intrFreq);
-        FSTranslatingPortProxy* vp;
-
-        vp = tc->getVirtProxy();
-        vp->writeHtoG(addr, (uint32_t)((cpuFreq / intrFreq) * 0.9988));
+        FSTranslatingPortProxy &vp = tc->getVirtProxy();
+        vp.writeHtoG(addr, (uint32_t)((cpuFreq / intrFreq) * 0.9988));
     }
 }
 
diff --git a/src/arch/alpha/linux/threadinfo.hh b/src/arch/alpha/linux/threadinfo.hh
index 262da9007..94e362fe7 100644
--- a/src/arch/alpha/linux/threadinfo.hh
+++ b/src/arch/alpha/linux/threadinfo.hh
@@ -78,8 +78,8 @@ class ThreadInfo
         if (!addr)
             addr = tc->readMiscRegNoEffect(AlphaISA::IPR_PALtemp23);
 
-        PortProxy* p = tc->getPhysProxy();
-        p->readBlob(addr, (uint8_t *)&sp, sizeof(Addr));
+        PortProxy &p = tc->getPhysProxy();
+        p.readBlob(addr, (uint8_t *)&sp, sizeof(Addr));
 
         return sp & ~ULL(0x3fff);
     }