Refactor interface between backend and frontend (#530)

* Rename to use Config, rather than StateHandle/Globals/Backend
* Make Backend a type on Config that contains the address space management implementation
* Make Ranges part of the Backend configuration, so we can reuse code for different ways of managing memory
* Pull the common chains of range definitions into separate files for reuse.
* Move PagemapEntry to CommonConfig
* Expose Pagemap through backend, so frontend doesn't see Pagemap directly
* Remove global Pal and use DefaultPal, where one is not pass explicitly.

Co-authored-by: David Chisnall <davidchisnall@users.noreply.github.com>
Co-authored-by: Nathaniel Filardo <105816689+nwf-msr@users.noreply.github.com>

src/test/perf/contention/contention.cc

@@ -154,7 +154,7 @@ void test_tasks(size_t num_tasks, size_t count, size_t size)
   }
 
 #ifndef NDEBUG
-  snmalloc::debug_check_empty<Globals>();
+  snmalloc::debug_check_empty<StandardConfig>();
 #endif
 };
 

src/test/perf/external_pointer/externalpointer.cc

@@ -19,7 +19,7 @@ namespace test
     {
       size_t rand = (size_t)r.next();
       size_t offset = bits::clz(rand);
-      if constexpr (Pal::address_bits > 32)
+      if constexpr (DefaultPal::address_bits > 32)
       {
         if (offset > 30)
           offset = 30;
@@ -47,7 +47,7 @@ namespace test
       alloc.dealloc(objects[i]);
     }
 
-    snmalloc::debug_check_empty<Globals>();
+    snmalloc::debug_check_empty<StandardConfig>();
   }
 
   void test_external_pointer(xoroshiro::p128r64& r)

src/test/perf/singlethread/singlethread.cc

@@ -60,7 +60,7 @@ void test_alloc_dealloc(size_t count, size_t size, bool write)
     }
   }
 
-  snmalloc::debug_check_empty<Globals>();
+  snmalloc::debug_check_empty<StandardConfig>();
 }
 
 int main(int, char**)