mem: Assert that requests have non-negative size.

Would have saved me much debugging time if these
had been in there previously.

src/base/chunk_generator.hh

@@ -82,6 +82,7 @@ class ChunkGenerator
     {
         // chunkSize must be a power of two
         assert(chunkSize == 0 || isPowerOf2(chunkSize));
+        assert(totalSize >= 0);
 
         // set up initial chunk.
         curAddr = startAddr;

src/mem/request.hh

@@ -172,6 +172,7 @@ class Request : public FastAlloc
      * allocated Request object. */
     void setPhys(Addr _paddr, int _size, int _flags)
     {
+        assert(_size >= 0);
         paddr = _paddr;
         size = _size;
         flags = _flags;
@@ -188,6 +189,7 @@ class Request : public FastAlloc
      * allocated Request object. */
     void setVirt(int _asid, Addr _vaddr, int _size, int _flags, Addr _pc)
     {
+        assert(_size >= 0);
         asid = _asid;
         vaddr = _vaddr;
         size = _size;