add noexcept attributes to improve mi_free codegen

Author: daanx

include/mimalloc-internal.h

@@ -37,9 +37,9 @@ terms of the MIT license. A copy of the license can be found in the file
 #endif
 
 #if defined(__cplusplus)
-#define mi_decl_externc   extern "C"
+#define mi_decl_externc       extern "C"
 #else
-#define mi_decl_externc
+#define mi_decl_externc  
 #endif
 
 // "options.c"
@@ -100,7 +100,7 @@ void       _mi_abandoned_await_readers(void);
 // "page.c"
 void*      _mi_malloc_generic(mi_heap_t* heap, size_t size)  mi_attr_noexcept mi_attr_malloc;
 
-void       _mi_page_retire(mi_page_t* page);                                  // free the page if there are no other pages with many free blocks
+void       _mi_page_retire(mi_page_t* page) mi_attr_noexcept;                  // free the page if there are no other pages with many free blocks
 void       _mi_page_unfull(mi_page_t* page);
 void       _mi_page_free(mi_page_t* page, mi_page_queue_t* pq, bool force);   // free the page
 void       _mi_page_abandon(mi_page_t* page, mi_page_queue_t* pq);            // abandon the page, to be picked up by another thread...

src/alloc.c

@@ -435,7 +435,7 @@ mi_block_t* _mi_page_ptr_unalign(const mi_segment_t* segment, const mi_page_t* p
 }
 
 
-static void mi_decl_noinline mi_free_generic(const mi_segment_t* segment, bool local, void* p) {
+static void mi_decl_noinline mi_free_generic(const mi_segment_t* segment, bool local, void* p) mi_attr_noexcept {
   mi_page_t* const page = _mi_segment_page_of(segment, p);
   mi_block_t* const block = (mi_page_has_aligned(page) ? _mi_page_ptr_unalign(segment, page, p) : (mi_block_t*)p);
   mi_stat_free(page, block);

src/page.c

@@ -386,7 +386,7 @@ void _mi_page_free(mi_page_t* page, mi_page_queue_t* pq, bool force) {
 // Note: called from `mi_free` and benchmarks often
 // trigger this due to freeing everything and then
 // allocating again so careful when changing this.
-void _mi_page_retire(mi_page_t* page) {
+void _mi_page_retire(mi_page_t* page) mi_attr_noexcept {
   mi_assert_internal(page != NULL);
   mi_assert_expensive(_mi_page_is_valid(page));
   mi_assert_internal(mi_page_all_free(page));