[WIP][libc] Add freelist malloc

Author: PiJoules

libc/config/baremetal/riscv/entrypoints.txt

@@ -170,6 +170,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.ldiv
     libc.src.stdlib.llabs
     libc.src.stdlib.lldiv
+    libc.src.stdlib.malloc
     libc.src.stdlib.qsort
     libc.src.stdlib.rand
     libc.src.stdlib.srand

libc/src/__support/CPP/new.h

@@ -74,6 +74,9 @@ LIBC_INLINE void *operator new[](size_t size, std::align_val_t align,
   return LIBC_NAMESPACE::AllocChecker::aligned_alloc(size, align, ac);
 }
 
+LIBC_INLINE void *operator new(size_t, void *__p) { return __p; }
+LIBC_INLINE void *operator new[](size_t, void *__p) { return __p; }
+
 // The ideal situation would be to define the various flavors of operator delete
 // inlinelike we do with operator new above. However, since we need operator
 // delete prototypes to match those specified by the C++ standard, we cannot

libc/src/__support/CPP/type_traits.h

@@ -12,6 +12,7 @@
 #include "src/__support/CPP/type_traits/add_lvalue_reference.h"
 #include "src/__support/CPP/type_traits/add_pointer.h"
 #include "src/__support/CPP/type_traits/add_rvalue_reference.h"
+#include "src/__support/CPP/type_traits/aligned_storage.h"
 #include "src/__support/CPP/type_traits/bool_constant.h"
 #include "src/__support/CPP/type_traits/conditional.h"
 #include "src/__support/CPP/type_traits/decay.h"

libc/src/__support/CPP/type_traits/aligned_storage.h

@@ -0,0 +1,27 @@
+//===-- aligned_storage type_traits    --------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_ALIGNED_STORAGE_H
+#define LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_ALIGNED_STORAGE_H
+
+#include <stddef.h> // size_t
+
+namespace LIBC_NAMESPACE::cpp {
+
+template <size_t Len, size_t Align> struct aligned_storage {
+  struct type {
+    alignas(Align) unsigned char data[Len];
+  };
+};
+
+template <size_t Len, size_t Align>
+using aligned_storage_t = typename aligned_storage<Len, Align>::type;
+
+} // namespace LIBC_NAMESPACE::cpp
+
+#endif // LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_ALIGNED_STORAGE_H

libc/src/__support/fixedvector.h

@@ -24,6 +24,18 @@ template <typename T, size_t CAPACITY> class FixedVector {
 public:
   constexpr FixedVector() = default;
 
+  template <typename It> FixedVector(It begin, It end) {
+    for (; begin != end; ++begin) {
+      push_back(*begin);
+    }
+  }
+
+  FixedVector(size_t count, const T &value) {
+    for (size_t i = 0; i < count; ++i) {
+      push_back(value);
+    }
+  }
+
   bool push_back(const T &obj) {
     if (item_count == CAPACITY)
       return false;
@@ -36,6 +48,9 @@ template <typename T, size_t CAPACITY> class FixedVector {
 
   T &back() { return store[item_count - 1]; }
 
+  T &operator[](size_t idx) { return store[idx]; }
+  const T &operator[](size_t idx) const { return store[idx]; }
+
   bool pop_back() {
     if (item_count == 0)
       return false;
@@ -44,6 +59,7 @@ template <typename T, size_t CAPACITY> class FixedVector {
   }
 
   bool empty() const { return item_count == 0; }
+  size_t size() const { return item_count; }
 
   // Empties the store for all practical purposes.
   void reset() { item_count = 0; }
@@ -63,6 +79,10 @@ template <typename T, size_t CAPACITY> class FixedVector {
     return reverse_iterator{&store[item_count]};
   }
   LIBC_INLINE constexpr reverse_iterator rend() { return store.rend(); }
+
+  using iterator = typename cpp::array<T, CAPACITY>::iterator;
+  LIBC_INLINE constexpr iterator begin() { return store.begin(); }
+  LIBC_INLINE constexpr iterator end() { return iterator{&store[item_count]}; }
 };
 
 } // namespace LIBC_NAMESPACE

libc/src/stdlib/CMakeLists.txt

@@ -379,8 +379,20 @@ elseif(LIBC_TARGET_OS_IS_GPU)
     aligned_alloc
   )
 else()
-  add_entrypoint_external(
+  add_entrypoint_object(
     malloc
+    SRCS
+      freelist_malloc.cpp
+    HDRS
+      malloc.h
+    DEPENDS
+      libc.src.__support.CPP.new
+      libc.src.__support.CPP.optional
+      libc.src.__support.CPP.span
+      libc.src.__support.CPP.type_traits
+      libc.src.__support.fixedvector
+      libc.src.string.memcpy
+      libc.src.string.memset
   )
   add_entrypoint_external(
     free