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.

1 files changed, 5 insertions, 8 deletions

diff --git a/src/arch/x86/linux/system.cc b/src/arch/x86/linux/system.cc
index a933868d1..f473af40e 100644
--- a/src/arch/x86/linux/system.cc
+++ b/src/arch/x86/linux/system.cc
@@ -67,9 +67,6 @@ LinuxX86System::initState()
     // The location of the real mode data structure.
     const Addr realModeData = 0x90200;
 
-    // A port proxy to write to memory.
-    PortProxy* physProxy = threadContexts[0]->getPhysProxy();
-
     /*
      * Deal with the command line stuff.
      */
@@ -82,15 +79,15 @@ LinuxX86System::initState()
     if (commandLine.length() + 1 > realModeData - commandLineBuff)
         panic("Command line \"%s\" is longer than %d characters.\n",
                 commandLine, realModeData - commandLineBuff - 1);
-    physProxy->writeBlob(commandLineBuff,
-            (uint8_t *)commandLine.c_str(), commandLine.length() + 1);
+    physProxy.writeBlob(commandLineBuff, (uint8_t *)commandLine.c_str(),
+                        commandLine.length() + 1);
 
     // Generate a pointer of the right size and endianness to put into
     // commandLinePointer.
     uint32_t guestCommandLineBuff =
         X86ISA::htog((uint32_t)commandLineBuff);
-    physProxy->writeBlob(commandLinePointer,
-            (uint8_t *)&guestCommandLineBuff, sizeof(guestCommandLineBuff));
+    physProxy.writeBlob(commandLinePointer, (uint8_t *)&guestCommandLineBuff,
+                        sizeof(guestCommandLineBuff));
 
     /*
      * Screen Info.
@@ -127,7 +124,7 @@ LinuxX86System::initState()
     // A pointer to the buffer for E820 entries.
     const Addr e820MapPointer = realModeData + 0x2d0;
 
-    e820Table->writeTo(getSystemPort(), e820MapNrPointer, e820MapPointer);
+    e820Table->writeTo(physProxy, e820MapNrPointer, e820MapPointer);
 
     /*
      * Pass the location of the real mode data structure to the kernel