resolve #201 with a platform-selective REP MOVSB implementation

include/mimalloc-internal.h

@@ -174,6 +174,22 @@ bool        _mi_page_is_valid(mi_page_t* page);
 #define EOVERFLOW (75)
 #endif
 
+// ------------------------------------------------------
+// Fast `memcpy()` on x86(_64) platforms unavailable,
+// use REP MOVSB
+// ------------------------------------------------------
+
+#if defined(_M_IX86) || defined(_M_X64)
+#include <intrin.h>
+#define _mi_memcpy _mi_memcpy_rep_movsb
+static inline void _mi_memcpy_rep_movsb (void *d, const void *s, size_t n) {
+  __movsb(d, s, n);
+  return;
+}
+#else
+#define _mi_memcpy memcpy
+#endif
+
 
 /* -----------------------------------------------------------
   Inlined definitions

src/alloc-aligned.c

@@ -137,7 +137,7 @@ static void* mi_heap_realloc_zero_aligned_at(mi_heap_t* heap, void* p, size_t ne
           memset((uint8_t*)newp + start, 0, newsize - start);
         }
       }
-      memcpy(newp, p, (newsize > size ? size : newsize));
+      _mi_memcpy(newp, p, (newsize > size ? size : newsize));
       mi_free(p); // only free if successful
     }
     return newp;

src/alloc-posix.c

@@ -99,7 +99,7 @@ mi_decl_restrict unsigned short* mi_wcsdup(const unsigned short* s) mi_attr_noex
   size_t size = (len+1)*sizeof(unsigned short);
   unsigned short* p = (unsigned short*)mi_malloc(size);
   if (p != NULL) {
-    memcpy(p,s,size);
+    _mi_memcpy(p,s,size);
   }
   return p;
 }

src/alloc.c

@@ -571,7 +571,7 @@ void* _mi_heap_realloc_zero(mi_heap_t* heap, void* p, size_t newsize, bool zero)
       size_t start = (size >= sizeof(intptr_t) ? size - sizeof(intptr_t) : 0);
       memset((uint8_t*)newp + start, 0, newsize - start);
     }
-    memcpy(newp, p, (newsize > size ? size : newsize));
+    _mi_memcpy(newp, p, (newsize > size ? size : newsize));
     mi_free(p); // only free if successful
   }
   return newp;
@@ -638,7 +638,7 @@ mi_decl_restrict char* mi_heap_strdup(mi_heap_t* heap, const char* s) mi_attr_no
   if (s == NULL) return NULL;
   size_t n = strlen(s);
   char* t = (char*)mi_heap_malloc(heap,n+1);
-  if (t != NULL) memcpy(t, s, n + 1);
+  if (t != NULL) _mi_memcpy(t, s, n + 1);
   return t;
 }
 
@@ -654,7 +654,7 @@ mi_decl_restrict char* mi_heap_strndup(mi_heap_t* heap, const char* s, size_t n)
   mi_assert_internal(m <= n);
   char* t = (char*)mi_heap_malloc(heap, m+1);
   if (t == NULL) return NULL;
-  memcpy(t, s, m);
+  _mi_memcpy(t, s, m);
   t[m] = 0;
   return t;
 }

src/heap.c

@@ -193,7 +193,7 @@ mi_heap_t* mi_heap_new(void) {
   mi_heap_t* bheap = mi_heap_get_backing();
   mi_heap_t* heap = mi_heap_malloc_tp(bheap, mi_heap_t);  // todo: OS allocate in secure mode?
   if (heap==NULL) return NULL;
-  memcpy(heap, &_mi_heap_empty, sizeof(mi_heap_t));
+  _mi_memcpy(heap, &_mi_heap_empty, sizeof(mi_heap_t));
   heap->tld = bheap->tld;
   heap->thread_id = _mi_thread_id();
   _mi_random_split(&bheap->random, &heap->random);
@@ -219,7 +219,7 @@ static void mi_heap_reset_pages(mi_heap_t* heap) {
 #ifdef MI_MEDIUM_DIRECT
   memset(&heap->pages_free_medium, 0, sizeof(heap->pages_free_medium));
 #endif
-  memcpy(&heap->pages, &_mi_heap_empty.pages, sizeof(heap->pages));
+  _mi_memcpy(&heap->pages, &_mi_heap_empty.pages, sizeof(heap->pages));
   heap->thread_delayed_free = NULL;
   heap->page_count = 0;
 }

src/init.c

@@ -188,7 +188,7 @@ static bool _mi_heap_init(void) {
     // OS allocated so already zero initialized
     mi_tld_t*  tld = &td->tld;
     mi_heap_t* heap = &td->heap;
-    memcpy(heap, &_mi_heap_empty, sizeof(*heap));
+    _mi_memcpy(heap, &_mi_heap_empty, sizeof(*heap));
     heap->thread_id = _mi_thread_id();
     _mi_random_init(&heap->random);
     heap->cookie  = _mi_heap_random_next(heap) | 1;

src/options.c

@@ -183,7 +183,7 @@ static void mi_out_buf(const char* msg, void* arg) {
   if (start+n >= MI_MAX_DELAY_OUTPUT) {
     n = MI_MAX_DELAY_OUTPUT-start-1;
   }
-  memcpy(&out_buf[start], msg, n);
+  _mi_memcpy(&out_buf[start], msg, n);
 }
 
 static void mi_out_buf_flush(mi_output_fun* out, bool no_more_buf, void* arg) {

src/random.c

@@ -115,7 +115,7 @@ static void chacha_init(mi_random_ctx_t* ctx, const uint8_t key[32], uint64_t no
 
 static void chacha_split(mi_random_ctx_t* ctx, uint64_t nonce, mi_random_ctx_t* ctx_new) {
   memset(ctx_new, 0, sizeof(*ctx_new));
-  memcpy(ctx_new->input, ctx->input, sizeof(ctx_new->input));
+  _mi_memcpy(ctx_new->input, ctx->input, sizeof(ctx_new->input));
   ctx_new->input[12] = 0;
   ctx_new->input[13] = 0;
   ctx_new->input[14] = (uint32_t)nonce;