[NFC] Make the Apple PAL use the generic BSD code.

src/pal/pal_apple.h

@@ -1,89 +1,27 @@
 #pragma once
 
 #ifdef __APPLE__
-#  include "../ds/bits.h"
-#  include "../mem/allocconfig.h"
-
-#  include <pthread.h>
-#  include <strings.h>
-#  include <sys/mman.h>
-
-extern "C" int puts(const char* str);
+#  include "pal_bsd.h"
 
 namespace snmalloc
 {
   /**
    * PAL implementation for Apple systems (macOS, iOS, watchOS, tvOS...).
+   *
+   * XNU behaves exactly like a generic BSD platform but this class exists
+   * as a place to add XNU-specific behaviour later, if required.
    */
-  class PALApple
+  class PALApple : public PALBSD<PALApple>
   {
   public:
     /**
-     * Bitmap of PalFeatures flags indicating the optional features that this
-     * PAL supports.
+     * The features exported by this PAL.
+     *
+     * Currently, these are identical to the generic BSD PAL.  This field is
+     * declared explicitly to remind anyone who modifies this class that they
+     * should add any required features.
      */
-    static constexpr uint64_t pal_features = LazyCommit;
-    static void error(const char* const str)
-    {
-      puts(str);
-      abort();
-    }
-
-    /// Notify platform that we will not be using these pages
-    void notify_not_using(void* p, size_t size) noexcept
-    {
-      assert(bits::is_aligned_block<OS_PAGE_SIZE>(p, size));
-      madvise(p, size, MADV_FREE);
-    }
-
-    /// Notify platform that we will be using these pages
-    template<ZeroMem zero_mem>
-    void notify_using(void* p, size_t size) noexcept
-    {
-      assert(
-        bits::is_aligned_block<OS_PAGE_SIZE>(p, size) || (zero_mem == NoZero));
-      if constexpr (zero_mem == YesZero)
-        zero(p, size);
-    }
-
-    /// OS specific function for zeroing memory
-    template<bool page_aligned = false>
-    void zero(void* p, size_t size) noexcept
-    {
-      if (page_aligned || bits::is_aligned_block<OS_PAGE_SIZE>(p, size))
-      {
-        assert(bits::is_aligned_block<OS_PAGE_SIZE>(p, size));
-        void* r = mmap(
-          p,
-          size,
-          PROT_READ | PROT_WRITE,
-          MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
-          -1,
-          0);
-
-        if (r != MAP_FAILED)
-          return;
-      }
-
-      bzero(p, size);
-    }
-
-    template<bool committed>
-    void* reserve(size_t* size) noexcept
-    {
-      void* p = mmap(
-        NULL,
-        *size,
-        PROT_READ | PROT_WRITE,
-        MAP_PRIVATE | MAP_ANONYMOUS,
-        -1,
-        0);
-
-      if (p == MAP_FAILED)
-        error("Out of memory");
-
-      return p;
-    }
+    static constexpr uint64_t pal_features = PALBSD::pal_features;
   };
-}
+} // namespace snmalloc
 #endif