Get rid of zero length array extension (#1076)

VKCOM · Sep 3, 2024 · e511730 · e511730
1 parent 3cb2120
commit e511730
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Showing 3 changed files with 96 additions and 86 deletions.
diff --git a/runtime-core/core-types/decl/array_decl.inl b/runtime-core/core-types/decl/array_decl.inl
@@ -26,13 +26,6 @@ struct array_size {
   inline array_size &min(const array_size &other) noexcept;
 };
 
-#if defined(__clang__) || (defined(__GNUC__) && __GNUC__ < 10)
-// clang complains about 'flexible array member x of type T[] with non-trivial destruction'
-#define KPHP_ARRAY_TAIL_SIZE 0
-#else
-// gcc10 complains about out-of-bounds access to an array of zero size
-#define KPHP_ARRAY_TAIL_SIZE
-#endif
 
 namespace dl {
 template<class T, class TT, class T1>
@@ -95,23 +88,24 @@ private:
     uint32_t string_size{0};
   };
 
-  struct array_inner : array_inner_control {
+  struct alignas(array_bucket) array_inner : array_inner_control {
     static constexpr uint32_t MAX_HASHTABLE_SIZE = (1 << 26);
     //empty hash_entry identified by (next == EMPTY_POINTER)
     static constexpr entry_pointer_type EMPTY_POINTER = 0;
-
-    array_bucket entries[KPHP_ARRAY_TAIL_SIZE];
+    static constexpr size_t ENTRIES_OFFSET = sizeof(array_inner);
 
     inline bool is_vector() const noexcept __attribute__ ((always_inline));
 
+    inline array_bucket* entries() noexcept __attribute__ ((always_inline));
+    inline const array_bucket* entries() const noexcept __attribute__ ((always_inline));
+
     inline list_hash_entry *get_entry(entry_pointer_type pointer) const __attribute__ ((always_inline));
     inline entry_pointer_type get_pointer(list_hash_entry *entry) const __attribute__ ((always_inline));
 
     inline const array_bucket *begin() const __attribute__ ((always_inline)) ubsan_supp("alignment");
     inline const array_bucket *next(const array_bucket *ptr) const __attribute__ ((always_inline)) ubsan_supp("alignment");
     inline const array_bucket *prev(const array_bucket *ptr) const __attribute__ ((always_inline)) ubsan_supp("alignment");
     inline const array_bucket *end() const __attribute__ ((always_inline)) ubsan_supp("alignment");
-
     inline array_bucket *begin() __attribute__ ((always_inline)) ubsan_supp("alignment");
     inline array_bucket *next(array_bucket *ptr) __attribute__ ((always_inline)) ubsan_supp("alignment");
     inline array_bucket *prev(array_bucket *ptr) __attribute__ ((always_inline)) ubsan_supp("alignment");

diff --git a/runtime-core/core-types/decl/array_iterator.h b/runtime-core/core-types/decl/array_iterator.h
@@ -49,7 +49,7 @@ class array_iterator {
 
   inline key_type get_key() const noexcept __attribute__ ((always_inline)) {
     if (self_->is_vector()) {
-      return key_type{static_cast<int64_t>(reinterpret_cast<value_type *>(entry_) - reinterpret_cast<value_type *>(self_->entries))};
+      return key_type{static_cast<int64_t>(reinterpret_cast<value_type *>(entry_) - reinterpret_cast<value_type *>(self_->entries()))};
     }
 
     if (is_string_key()) {
@@ -112,15 +112,15 @@ class array_iterator {
   static inline array_iterator make_begin(std::add_const_t<array_type> &arr) noexcept __attribute__ ((always_inline)) {
     static_assert(std::is_const<T>{}, "expected to be const");
     return arr.is_vector()
-           ? array_iterator{arr.p, arr.p->entries}
+           ? array_iterator{arr.p, arr.p->entries()}
            : array_iterator{arr.p, arr.p->begin()};
   }
 
   static inline array_iterator make_begin(std::remove_const_t<array_type> &arr) noexcept __attribute__ ((always_inline)) {
     static_assert(!std::is_const<T>{}, "expected to be mutable");
     if (arr.is_vector()) {
       arr.mutate_if_vector_shared();
-      return array_iterator{arr.p, arr.p->entries};
+      return array_iterator{arr.p, arr.p->entries()};
     }
 
     arr.mutate_if_map_shared();
@@ -129,7 +129,7 @@ class array_iterator {
 
   static inline array_iterator make_end(array_type &arr) noexcept __attribute__ ((always_inline)) {
     return arr.is_vector()
-           ? array_iterator{arr.p, reinterpret_cast<list_hash_type *>(reinterpret_cast<value_type *>(arr.p->entries) + arr.p->size)}
+           ? array_iterator{arr.p, reinterpret_cast<list_hash_type *>(reinterpret_cast<value_type *>(arr.p->entries()) + arr.p->size)}
            : array_iterator{arr.p, arr.p->end()};
   }
 
@@ -147,7 +147,7 @@ class array_iterator {
         return make_end(arr);
       }
 
-      return array_iterator{arr.p, reinterpret_cast<list_hash_type *>(reinterpret_cast<value_type *>(arr.p->entries) + n)};
+      return array_iterator{arr.p, reinterpret_cast<list_hash_type *>(reinterpret_cast<value_type *>(arr.p->entries()) + n)};
     }
 
     if (n < -l / 2) {