Add an Architecture Abstraction Layer.

Currently, we support one architecture, but this provides a layer for
adding other architectures without adding more nested `#ifdef`s.

Fixes #42

src/ds/aba.h

@@ -89,7 +89,7 @@ namespace snmalloc
     bool compare_exchange(Cmp& expect, T* value)
     {
 #ifdef PLATFORM_IS_X86
-#  if defined(_MSC_VER) && defined(PLATFORM_BITS_64)
+#  if defined(_MSC_VER) && defined(SNMALLOC_VA_BITS_64)
       return _InterlockedCompareExchange128(
         (volatile __int64*)&linked,
         expect.aba + 1,

src/ds/bits.h

@@ -3,9 +3,9 @@
 #include <limits>
 #include <stddef.h>
 
-
 // #define USE_LZCNT
 
+#include "aal/aal.h"
 #include "address.h"
 #include "defines.h"
 
@@ -55,87 +55,11 @@ namespace snmalloc
 
     static constexpr size_t ADDRESS_BITS = is64() ? 48 : 32;
 
-    inline void pause()
-    {
-#if defined(PLATFORM_IS_X86)
-      _mm_pause();
-#else
-#  warning "Missing pause intrinsic"
-#endif
-    }
-
-    inline void prefetch(void* ptr)
-    {
-#if defined(PLATFORM_IS_X86)
-      _mm_prefetch(reinterpret_cast<const char*>(ptr), _MM_HINT_T0);
-#else
-#  warning "Missing prefetch intrinsic"
-#endif
-    }
-
-    inline uint64_t tick()
-    {
-#if defined(PLATFORM_IS_X86)
-#  if defined(_MSC_VER)
-      return __rdtsc();
-#  elif defined(__clang__)
-      return __builtin_readcyclecounter();
-#  else
-      return __builtin_ia32_rdtsc();
-#  endif
-#else
-#  error Define CPU tick for this platform
-#endif
-    }
-
-    inline uint64_t tickp()
-    {
-#if defined(PLATFORM_IS_X86)
-#  if defined(_MSC_VER)
-      unsigned int aux;
-      return __rdtscp(&aux);
-#  else
-      unsigned aux;
-      return __builtin_ia32_rdtscp(&aux);
-#  endif
-#else
-#  error Define CPU tick for this platform
-#endif
-    }
-
-    inline void halt_out_of_order()
-    {
-#if defined(PLATFORM_IS_X86)
-#  if defined(_MSC_VER)
-      int cpu_info[4];
-      __cpuid(cpu_info, 0);
-#  else
-      unsigned int eax, ebx, ecx, edx;
-      __get_cpuid(0, &eax, &ebx, &ecx, &edx);
-#  endif
-#else
-#  error Define CPU benchmark start time for this platform
-#endif
-    }
-
-    inline uint64_t benchmark_time_start()
-    {
-      halt_out_of_order();
-      return tick();
-    }
-
-    inline uint64_t benchmark_time_end()
-    {
-      uint64_t t = tickp();
-      halt_out_of_order();
-      return t;
-    }
-
     inline size_t clz(size_t x)
     {
 #if defined(_MSC_VER)
 #  ifdef USE_LZCNT
-#    ifdef PLATFORM_BITS_64
+#    ifdef SNMALLOC_VA_BITS_64
       return __lzcnt64(x);
 #    else
       return __lzcnt((uint32_t)x);
@@ -143,7 +67,7 @@ namespace snmalloc
 #  else
       unsigned long index;
 
-#    ifdef PLATFORM_BITS_64
+#    ifdef SNMALLOC_VA_BITS_64
       _BitScanReverse64(&index, x);
 #    else
       _BitScanReverse(&index, (unsigned long)x);
@@ -173,7 +97,7 @@ namespace snmalloc
     inline size_t rotr(size_t x, size_t n)
     {
 #if defined(_MSC_VER)
-#  ifdef PLATFORM_BITS_64
+#  ifdef SNMALLOC_VA_BITS_64
       return _rotr64(x, (int)n);
 #  else
       return _rotr((uint32_t)x, (int)n);
@@ -186,7 +110,7 @@ namespace snmalloc
     inline size_t rotl(size_t x, size_t n)
     {
 #if defined(_MSC_VER)
-#  ifdef PLATFORM_BITS_64
+#  ifdef SNMALLOC_VA_BITS_64
       return _rotl64(x, (int)n);
 #  else
       return _rotl((uint32_t)x, (int)n);
@@ -216,7 +140,7 @@ namespace snmalloc
     inline size_t ctz(size_t x)
     {
 #if defined(_MSC_VER)
-#  ifdef PLATFORM_BITS_64
+#  ifdef SNMALLOC_VA_BITS_64
       return _tzcnt_u64(x);
 #  else
       return _tzcnt_u32((uint32_t)x);
@@ -250,7 +174,7 @@ namespace snmalloc
       overflow = __builtin_mul_overflow(x, y, &prod);
       return prod;
 #elif defined(_MSC_VER)
-#  if defined(PLATFORM_BITS_64)
+#  if defined(SNMALLOC_VA_BITS_64)
       size_t high_prod;
       size_t prod = _umul128(x, y, &high_prod);
       overflow = high_prod != 0;

src/ds/defines.h

@@ -1,8 +1,6 @@
 #pragma once
 
 #ifdef _MSC_VER
-#  include <immintrin.h>
-#  include <intrin.h>
 #  define ALWAYSINLINE __forceinline
 #  define NOINLINE __declspec(noinline)
 #  define HEADER_GLOBAL __declspec(selectany)
@@ -14,8 +12,6 @@
 #else
 #  define likely(x) __builtin_expect(!!(x), 1)
 #  define unlikely(x) __builtin_expect(!!(x), 0)
-#  include <cpuid.h>
-#  include <emmintrin.h>
 #  define ALWAYSINLINE __attribute__((always_inline))
 #  define NOINLINE __attribute__((noinline))
 #  define SNMALLOC_SLOW_PATH NOINLINE
@@ -30,25 +26,6 @@
 #  endif
 #endif
 
-#if defined(__i386__) || defined(_M_IX86) || defined(_X86_) || \
-  defined(__amd64__) || defined(__x86_64__) || defined(_M_X64) || \
-  defined(_M_AMD64)
-#  define PLATFORM_IS_X86
-#  if defined(__linux__) && !defined(OPEN_ENCLAVE)
-#    include <x86intrin.h>
-#  endif
-#  if defined(__amd64__) || defined(__x86_64__) || defined(_M_X64) || \
-    defined(_M_AMD64)
-#    define PLATFORM_BITS_64
-#  else
-#    define PLATFORM_BITS_32
-#  endif
-#endif
-
-#if defined(_MSC_VER) && defined(PLATFORM_BITS_32)
-#  include <intsafe.h>
-#endif
-
 #ifndef __has_builtin
 #  define __has_builtin(x) 0
 #endif

src/ds/flaglock.h

@@ -13,7 +13,7 @@ namespace snmalloc
     FlagLock(std::atomic_flag& lock) : lock(lock)
     {
       while (lock.test_and_set(std::memory_order_acquire))
-        bits::pause();
+        AAL::pause();
     }
 
     ~FlagLock()

src/ds/mpscq.h

@@ -70,7 +70,7 @@ namespace snmalloc
       if (next != nullptr)
       {
         front = next;
-        bits::prefetch(&(next->next));
+        AAL::prefetch(&(next->next));
         assert(front);
         std::atomic_thread_fence(std::memory_order_acquire);
         invariant();