From b47b92749f87786ccbf0e6487654ceac9b7cdfb7 Mon Sep 17 00:00:00 2001
From: schrodingerzhu <i@zhuyi.fan>
Date: Thu, 9 Jan 2025 20:14:13 +0800
Subject: [PATCH] [wip] address CRs

---
 src/snmalloc/backend_helpers/buddy.h |  5 ++-
 src/snmalloc/ds_core/bits.h          |  8 ++---
 src/snmalloc/ds_core/helpers.h       | 10 +++---
 src/snmalloc/ds_core/redblacktree.h  | 42 +++++++++-------------
 src/snmalloc/global/memcpy.h         |  3 +-
 src/snmalloc/mem/corealloc.h         |  3 +-
 src/snmalloc/mem/freelist.h          |  6 ++--
 src/snmalloc/mem/remotecache.h       |  6 ++--
 src/snmalloc/pal/pal_linux.h         |  6 ++--
 src/snmalloc/pal/pal_posix.h         |  4 +--
 src/snmalloc/stl/array.h             |  9 +++++
 src/snmalloc/stl/cxx/array.h         | 15 ++++++++
 src/snmalloc/stl/cxx/utility.h       |  1 +
 src/snmalloc/stl/gnu/algorithm.h     | 53 ----------------------------
 src/snmalloc/stl/gnu/array.h         | 53 +++++++---------------------
 src/snmalloc/stl/gnu/utility.h       |  8 +++++
 16 files changed, 86 insertions(+), 146 deletions(-)
 create mode 100644 src/snmalloc/stl/array.h
 create mode 100644 src/snmalloc/stl/cxx/array.h
 delete mode 100644 src/snmalloc/stl/gnu/algorithm.h

diff --git a/src/snmalloc/backend_helpers/buddy.h b/src/snmalloc/backend_helpers/buddy.h
index 21ab0acdb..58cafacb1 100644
--- a/src/snmalloc/backend_helpers/buddy.h
+++ b/src/snmalloc/backend_helpers/buddy.h
@@ -1,7 +1,6 @@
 #pragma once
 
 #include "../ds/ds.h"
-#include "snmalloc/proxy/algorithm.h"
 
 namespace snmalloc
 {
@@ -24,7 +23,7 @@ namespace snmalloc
       RBTree<Rep> tree{};
     };
 
-    proxy::Array<Entry, MAX_SIZE_BITS - MIN_SIZE_BITS> entries{};
+    stl::Array<Entry, MAX_SIZE_BITS - MIN_SIZE_BITS> entries{};
     // All RBtrees at or above this index should be empty.
     size_t empty_at_or_above{0};
 
@@ -168,7 +167,7 @@ namespace snmalloc
       {
         if (Rep::equal(Rep::null, addr) || Rep::compare(e, addr))
         {
-          addr = proxy::exchange(e, addr);
+          addr = stl::exchange(e, addr);
         }
       }
 
diff --git a/src/snmalloc/ds_core/bits.h b/src/snmalloc/ds_core/bits.h
index ea932c7cb..1ff6426ea 100644
--- a/src/snmalloc/ds_core/bits.h
+++ b/src/snmalloc/ds_core/bits.h
@@ -371,9 +371,9 @@ namespace snmalloc
     }
 
     /**
-     * Implementation of `proxy::min`
+     * Implementation of `std::min`
      *
-     * `proxy::min` is in `<algorithm>`, so pulls in a lot of unneccessary code
+     * `bits::min` is in `<algorithm>`, so pulls in a lot of unneccessary code
      * We write our own to reduce the code that potentially needs reviewing.
      */
     template<typename T>
@@ -383,9 +383,9 @@ namespace snmalloc
     }
 
     /**
-     * Implementation of `proxy::max`
+     * Implementation of `std::max`
      *
-     * `proxy::max` is in `<algorithm>`, so pulls in a lot of unneccessary code
+     * `bits::max` is in `<algorithm>`, so pulls in a lot of unneccessary code
      * We write our own to reduce the code that potentially needs reviewing.
      */
     template<typename T>
diff --git a/src/snmalloc/ds_core/helpers.h b/src/snmalloc/ds_core/helpers.h
index fc204f461..3008da4f5 100644
--- a/src/snmalloc/ds_core/helpers.h
+++ b/src/snmalloc/ds_core/helpers.h
@@ -50,7 +50,7 @@ namespace snmalloc
     };
 
     static constexpr size_t rlength = bits::next_pow2_const(length);
-    proxy::Array<TWrap, rlength> array;
+    stl::Array<TWrap, rlength> array;
 
   public:
     constexpr const T& operator[](const size_t i) const
@@ -65,7 +65,7 @@ namespace snmalloc
   };
 #else
   template<size_t length, typename T>
-  using ModArray = proxy::Array<T, length>;
+  using ModArray = stl::Array<T, length>;
 #endif
 
   /**
@@ -144,7 +144,7 @@ namespace snmalloc
     /**
      * The buffer that is used to store the formatted output.
      */
-    proxy::Array<char, BufferSize> buffer;
+    stl::Array<char, BufferSize> buffer;
 
     /**
      * Space in the buffer, excluding a trailing null terminator.
@@ -254,7 +254,7 @@ namespace snmalloc
         append_char('-');
         s = 0 - s;
       }
-      proxy::Array<char, 20> buf{{0}};
+      stl::Array<char, 20> buf{{0}};
       const char digits[] = "0123456789";
       for (long i = static_cast<long>(buf.size() - 1); i >= 0; i--)
       {
@@ -284,7 +284,7 @@ namespace snmalloc
     {
       append_char('0');
       append_char('x');
-      proxy::Array<char, 16> buf{{0}};
+      stl::Array<char, 16> buf{{0}};
       const char hexdigits[] = "0123456789abcdef";
       // Length of string including null terminator
       static_assert(sizeof(hexdigits) == 0x11);
diff --git a/src/snmalloc/ds_core/redblacktree.h b/src/snmalloc/ds_core/redblacktree.h
index 0e3814ded..7fd3c61b8 100644
--- a/src/snmalloc/ds_core/redblacktree.h
+++ b/src/snmalloc/ds_core/redblacktree.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include "snmalloc/proxy/array.h"
+#include "snmalloc/stl/array.h"
 
 #include <stddef.h>
 #include <stdint.h>
@@ -18,9 +18,9 @@ namespace snmalloc
    */
   template<typename Rep>
   concept RBRepTypes = requires() {
-                         typename Rep::Handle;
-                         typename Rep::Contents;
-                       };
+    typename Rep::Handle;
+    typename Rep::Contents;
+  };
 
   /**
    * The representation must define operations on the holder and contents
@@ -41,29 +41,17 @@ namespace snmalloc
   template<typename Rep>
   concept RBRepMethods =
     requires(typename Rep::Handle hp, typename Rep::Contents k, bool b) {
-      {
-        Rep::get(hp)
-        } -> ConceptSame<typename Rep::Contents>;
-      {
-        Rep::set(hp, k)
-        } -> ConceptSame<void>;
-      {
-        Rep::is_red(k)
-        } -> ConceptSame<bool>;
-      {
-        Rep::set_red(k, b)
-        } -> ConceptSame<void>;
-      {
-        Rep::ref(b, k)
-        } -> ConceptSame<typename Rep::Handle>;
-      {
-        Rep::null
-        } -> ConceptSameModRef<const typename Rep::Contents>;
+      { Rep::get(hp) } -> ConceptSame<typename Rep::Contents>;
+      { Rep::set(hp, k) } -> ConceptSame<void>;
+      { Rep::is_red(k) } -> ConceptSame<bool>;
+      { Rep::set_red(k, b) } -> ConceptSame<void>;
+      { Rep::ref(b, k) } -> ConceptSame<typename Rep::Handle>;
+      { Rep::null } -> ConceptSameModRef<const typename Rep::Contents>;
       {
         typename Rep::Handle{const_cast<
           stl::remove_const_t<stl::remove_reference_t<decltype(Rep::root)>>*>(
           &Rep::root)}
-        } -> ConceptSame<typename Rep::Handle>;
+      } -> ConceptSame<typename Rep::Handle>;
     };
 
   template<typename Rep>
@@ -260,7 +248,7 @@ namespace snmalloc
     {
       friend class RBTree;
 
-      proxy::Array<RBStep, 128> path;
+      stl::Array<RBStep, 128> path;
       size_t length = 0;
 
       RBPath(typename Rep::Handle root)
@@ -496,7 +484,8 @@ namespace snmalloc
        */
       path.move(true);
       while (path.move(false))
-      {}
+      {
+      }
 
       K curr = path.curr();
 
@@ -747,7 +736,8 @@ namespace snmalloc
 
       auto path = get_root_path();
       while (path.move(true))
-      {}
+      {
+      }
 
       K result = path.curr();
 
diff --git a/src/snmalloc/global/memcpy.h b/src/snmalloc/global/memcpy.h
index 3664aed2d..eaac1e97f 100644
--- a/src/snmalloc/global/memcpy.h
+++ b/src/snmalloc/global/memcpy.h
@@ -1,6 +1,5 @@
 #pragma once
 #include "bounds_checks.h"
-#include "snmalloc/proxy/algorithm.h"
 
 namespace snmalloc
 {
@@ -157,7 +156,7 @@ namespace snmalloc
      */
     SNMALLOC_UNUSED_FUNCTION
     static constexpr size_t LargestRegisterSize =
-      proxy::max(sizeof(uint64_t), sizeof(void*));
+      bits::max(sizeof(uint64_t), sizeof(void*));
 
     /**
      * Hook for architecture-specific optimisations.
diff --git a/src/snmalloc/mem/corealloc.h b/src/snmalloc/mem/corealloc.h
index e32838935..f82ccc1c2 100644
--- a/src/snmalloc/mem/corealloc.h
+++ b/src/snmalloc/mem/corealloc.h
@@ -6,7 +6,6 @@
 #include "pool.h"
 #include "remotecache.h"
 #include "sizeclasstable.h"
-#include "snmalloc/stl/algorithm.h"
 #include "snmalloc/stl/new.h"
 #include "ticker.h"
 
@@ -223,7 +222,7 @@ namespace snmalloc
                pointer_offset(curr, rsize).template as_static<PreAllocObject>())
         {
           size_t insert_index = entropy.sample(count);
-          curr->next = proxy::exchange(
+          curr->next = stl::exchange(
             pointer_offset(bumpptr, insert_index * rsize)
               .template as_static<PreAllocObject>()
               ->next,
diff --git a/src/snmalloc/mem/freelist.h b/src/snmalloc/mem/freelist.h
index 60c744f18..fd91f6dcc 100644
--- a/src/snmalloc/mem/freelist.h
+++ b/src/snmalloc/mem/freelist.h
@@ -701,11 +701,11 @@ namespace snmalloc
        */
 
       // Pointer to the first element.
-      proxy::Array<void*, LENGTH> head{nullptr};
+      stl::Array<void*, LENGTH> head{nullptr};
       // Pointer to the reference to the last element.
       // In the empty case end[i] == &head[i]
       // This enables branch free enqueuing.
-      proxy::Array<void**, LENGTH> end{nullptr};
+      stl::Array<void**, LENGTH> end{nullptr};
 
       [[nodiscard]] Object::BQueuePtr<BQueue>* cast_end(uint32_t ix) const
       {
@@ -724,7 +724,7 @@ namespace snmalloc
       }
 
       SNMALLOC_NO_UNIQUE_ADDRESS
-      proxy::Array<uint16_t, RANDOM ? 2 : (TRACK_LENGTH ? 1 : 0)> length{};
+      stl::Array<uint16_t, RANDOM ? 2 : (TRACK_LENGTH ? 1 : 0)> length{};
 
     public:
       constexpr Builder() = default;
diff --git a/src/snmalloc/mem/remotecache.h b/src/snmalloc/mem/remotecache.h
index ec531d573..3d5ed70b8 100644
--- a/src/snmalloc/mem/remotecache.h
+++ b/src/snmalloc/mem/remotecache.h
@@ -32,8 +32,8 @@ namespace snmalloc
   {
     static_assert(RINGS > 0);
 
-    proxy::Array<freelist::Builder<false, true>, RINGS> open_builder;
-    proxy::Array<address_t, RINGS> open_meta = {0};
+    stl::Array<freelist::Builder<false, true>, RINGS> open_builder;
+    stl::Array<address_t, RINGS> open_meta = {0};
 
     SNMALLOC_FAST_PATH size_t
     ring_set(typename Config::PagemapEntry::SlabMetadata* meta)
@@ -190,7 +190,7 @@ namespace snmalloc
   template<typename Config>
   struct RemoteDeallocCache
   {
-    proxy::Array<freelist::Builder<false>, REMOTE_SLOTS> list;
+    stl::Array<freelist::Builder<false>, REMOTE_SLOTS> list;
 
     RemoteDeallocCacheBatchingImpl<Config> batching;
 
diff --git a/src/snmalloc/pal/pal_linux.h b/src/snmalloc/pal/pal_linux.h
index 836644a28..ffa16eb25 100644
--- a/src/snmalloc/pal/pal_linux.h
+++ b/src/snmalloc/pal/pal_linux.h
@@ -3,7 +3,7 @@
 #if defined(__linux__)
 #  include "../ds_core/ds_core.h"
 #  include "pal_posix.h"
-#  include "snmalloc/proxy/array.h"
+#  include "snmalloc/stl/array.h"
 
 #  include <string.h>
 #  include <sys/mman.h>
@@ -184,8 +184,8 @@ namespace snmalloc
       // protected routine.
       if (false == syscall_not_working.load(stl::memory_order_relaxed))
       {
-        auto current = proxy::begin(buffer);
-        auto target = proxy::end(buffer);
+        auto current = stl::begin(buffer);
+        auto target = stl::end(buffer);
         while (auto length = target - current)
         {
           // Reading data via syscall from system entropy pool.
diff --git a/src/snmalloc/pal/pal_posix.h b/src/snmalloc/pal/pal_posix.h
index 0afb83ae7..463b71071 100644
--- a/src/snmalloc/pal/pal_posix.h
+++ b/src/snmalloc/pal/pal_posix.h
@@ -418,8 +418,8 @@ namespace snmalloc
       auto fd = open("/dev/urandom", flags, 0);
       if (fd > 0)
       {
-        auto current = proxy::begin(buffer);
-        auto target = proxy::end(buffer);
+        auto current = stl::begin(buffer);
+        auto target = stl::end(buffer);
         while (auto length = static_cast<size_t>(target - current))
         {
           ret = read(fd, current, length);
diff --git a/src/snmalloc/stl/array.h b/src/snmalloc/stl/array.h
new file mode 100644
index 000000000..f398da0e0
--- /dev/null
+++ b/src/snmalloc/stl/array.h
@@ -0,0 +1,9 @@
+#pragma once
+
+#include "snmalloc/stl/common.h"
+
+#if SNMALLOC_USE_SELF_VENDORED_STL
+#  include "snmalloc/stl/gnu/array.h"
+#else
+#  include "snmalloc/stl/cxx/array.h"
+#endif
diff --git a/src/snmalloc/stl/cxx/array.h b/src/snmalloc/stl/cxx/array.h
new file mode 100644
index 000000000..9918f3087
--- /dev/null
+++ b/src/snmalloc/stl/cxx/array.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <array>
+
+namespace snmalloc
+{
+  namespace proxy
+  {
+    template<typename T, size_t N>
+    using Array = std::array<T, N>;
+
+    using std::begin;
+    using std::end;
+  } // namespace proxy
+} // namespace snmalloc
diff --git a/src/snmalloc/stl/cxx/utility.h b/src/snmalloc/stl/cxx/utility.h
index 0853239b2..93ee5df18 100644
--- a/src/snmalloc/stl/cxx/utility.h
+++ b/src/snmalloc/stl/cxx/utility.h
@@ -5,6 +5,7 @@ namespace snmalloc
   namespace stl
   {
     using std::declval;
+    using std::exchange;
     using std::forward;
     using std::move;
     template<class T1, class T2>
diff --git a/src/snmalloc/stl/gnu/algorithm.h b/src/snmalloc/stl/gnu/algorithm.h
deleted file mode 100644
index db3c38040..000000000
--- a/src/snmalloc/stl/gnu/algorithm.h
+++ /dev/null
@@ -1,53 +0,0 @@
-#pragma once
-
-#include "snmalloc/ds_core/defines.h"
-
-#ifndef SNMALLOC_USE_SELF_VENDORED_STL
-#  define SNMALLOC_USE_SELF_VENDORED_STL 0
-#endif
-
-#if SNMALLOC_USE_SELF_VENDORED_STL
-#  include "snmalloc/proxy/utility.h"
-#  if !defined(__GNUC__) && !defined(__clang__)
-#    error "cannot use vendored STL without GNU/Clang extensions"
-#  endif
-
-namespace snmalloc
-{
-  namespace proxy
-  {
-    template<typename T>
-    constexpr SNMALLOC_FAST_PATH const T& max(const T& a, const T& b)
-    {
-      return a < b ? b : a;
-    }
-
-    template<typename T>
-    constexpr SNMALLOC_FAST_PATH const T& min(const T& a, const T& b)
-    {
-      return a < b ? a : b;
-    }
-
-    template<typename A, typename B = A>
-    constexpr SNMALLOC_FAST_PATH A exchange(A& obj, B&& new_value)
-    {
-      A old_value = move(obj);
-      obj = forward<B>(new_value);
-      return old_value;
-    }
-
-  } // namespace proxy
-} // namespace snmalloc
-#else
-#  include <algorithm>
-
-namespace snmalloc
-{
-  namespace proxy
-  {
-    using std::exchange;
-    using std::max;
-    using std::min;
-  } // namespace proxy
-} // namespace snmalloc
-#endif
diff --git a/src/snmalloc/stl/gnu/array.h b/src/snmalloc/stl/gnu/array.h
index 2733ba388..e4f2630a5 100644
--- a/src/snmalloc/stl/gnu/array.h
+++ b/src/snmalloc/stl/gnu/array.h
@@ -1,29 +1,17 @@
 #pragma once
 
-#include "snmalloc/ds_core/defines.h"
-
-#ifndef SNMALLOC_USE_SELF_VENDORED_STL
-#  define SNMALLOC_USE_SELF_VENDORED_STL 0
-#endif
-
-#if SNMALLOC_USE_SELF_VENDORED_STL
-
-#  if !defined(__GNUC__) && !defined(__clang__)
-#    error "cannot use vendored STL without GNU/Clang extensions"
-#  endif
-
-#  include <stddef.h>
+#include <stddef.h>
 
 namespace snmalloc
 {
-  namespace proxy
+  namespace stl
   {
     template<typename T, size_t N>
     struct Array
     {
       // N is potentially 0, so we mark it with __extension__ attribute.
-      // expose this to public to allow aggregate initialization
-      __extension__ T storage[N];
+      // Expose this to public to allow aggregate initialization
+      __extension__ T _storage[N];
 
       [[nodiscard]] constexpr SNMALLOC_FAST_PATH size_t size() const
       {
@@ -32,12 +20,12 @@ namespace snmalloc
 
       constexpr T& operator[](size_t i)
       {
-        return storage[i];
+        return _storage[i];
       }
 
       constexpr const T& operator[](size_t i) const
       {
-        return storage[i];
+        return _storage[i];
       }
 
       using value_type = T;
@@ -47,32 +35,32 @@ namespace snmalloc
 
       [[nodiscard]] constexpr SNMALLOC_FAST_PATH iterator begin()
       {
-        return &storage[0];
+        return &_storage[0];
       }
 
       [[nodiscard]] constexpr SNMALLOC_FAST_PATH const_iterator begin() const
       {
-        return &storage[0];
+        return &_storage[0];
       }
 
       [[nodiscard]] constexpr SNMALLOC_FAST_PATH iterator end()
       {
-        return &storage[N];
+        return &_storage[N];
       }
 
       [[nodiscard]] constexpr SNMALLOC_FAST_PATH const_iterator end() const
       {
-        return &storage[N];
+        return &_storage[N];
       }
 
       [[nodiscard]] constexpr SNMALLOC_FAST_PATH T* data()
       {
-        return &storage[0];
+        return &_storage[0];
       }
 
       [[nodiscard]] constexpr SNMALLOC_FAST_PATH const T* data() const
       {
-        return &storage[0];
+        return &_storage[0];
       }
     };
 
@@ -123,20 +111,5 @@ namespace snmalloc
     {
       return &a[N];
     }
-  } // namespace proxy
-} // namespace snmalloc
-#else
-#  include <array>
-
-namespace snmalloc
-{
-  namespace proxy
-  {
-    template<typename T, size_t N>
-    using Array = std::array<T, N>;
-
-    using std::begin;
-    using std::end;
-  } // namespace proxy
+  } // namespace stl
 } // namespace snmalloc
-#endif
diff --git a/src/snmalloc/stl/gnu/utility.h b/src/snmalloc/stl/gnu/utility.h
index 193613097..03a07c921 100644
--- a/src/snmalloc/stl/gnu/utility.h
+++ b/src/snmalloc/stl/gnu/utility.h
@@ -64,5 +64,13 @@ namespace snmalloc
       T1 first;
       T2 second;
     };
+
+    template<typename A, typename B = A>
+    constexpr SNMALLOC_FAST_PATH A exchange(A& obj, B&& new_value)
+    {
+      A old_value = move(obj);
+      obj = forward<B>(new_value);
+      return old_value;
+    }
   } // namespace stl
 } // namespace snmalloc