mem: Make Request getters const

This patch tidies up the Request class, making all getters const. The
odd one out is incAccessDepth which is called by the memory system as
packets carry the request around. This is also const to enable the
packet to hold on to a const Request.

src/mem/request.hh

@@ -410,13 +410,13 @@ class Request
      * Accessor for paddr.
      */
     bool
-    hasPaddr()
+    hasPaddr() const
     {
         return privateFlags.isSet(VALID_PADDR);
     }
 
     Addr
-    getPaddr()
+    getPaddr() const
     {
         assert(privateFlags.isSet(VALID_PADDR));
         return _paddr;
@@ -437,19 +437,19 @@ class Request
      * Level of the cache hierachy where this request was responded to
      * (e.g. 0 = L1; 1 = L2).
      */
-    int depth;
+    mutable int depth;
 
     /**
      *  Accessor for size.
      */
     bool
-    hasSize()
+    hasSize() const
     {
         return privateFlags.isSet(VALID_SIZE);
     }
 
     int
-    getSize()
+    getSize() const
     {
         assert(privateFlags.isSet(VALID_SIZE));
         return _size;
@@ -512,7 +512,7 @@ class Request
 
     /** Accesssor for the requestor id. */
     MasterID
-    masterId()
+    masterId() const
     {
         return _masterId;
     }
@@ -530,7 +530,7 @@ class Request
 
     /** Accessor function for asid.*/
     int
-    getAsid()
+    getAsid() const
     {
         assert(privateFlags.isSet(VALID_VADDR));
         return _asid;
@@ -545,7 +545,7 @@ class Request
 
     /** Accessor function for architecture-specific flags.*/
     ArchFlagsType
-    getArchFlags()
+    getArchFlags() const
     {
         assert(privateFlags.isSet(VALID_PADDR|VALID_VADDR));
         return _flags & ARCH_BITS;
@@ -553,7 +553,7 @@ class Request
 
     /** Accessor function to check if sc result is valid. */
     bool
-    extraDataValid()
+    extraDataValid() const
     {
         return privateFlags.isSet(VALID_EXTRA_DATA);
     }
@@ -621,7 +621,7 @@ class Request
      * Increment/Get the depth at which this request is responded to.
      * This currently happens when the request misses in any cache level.
      */
-    void incAccessDepth() { depth++; }
+    void incAccessDepth() const { depth++; }
     int getAccessDepth() const { return depth; }
 
     /**