feat(cortex): expose malloc internals for runtime diagnostics

targets/cortex-m/malloc.cpp

@@ -13,7 +13,7 @@
 
 #include <base/base.h>
 
-#include <ld_symbols.h>
+#include <malloc_internal.h>
 
 #define DIAG_ALLOC      1
 #define DIAG_HEAP       2
@@ -49,19 +49,9 @@ OPTIMIZE void* calloc(size_t size, size_t count)
     return _malloc_impl(size * count, true);
 }
 
-struct free_list
-{
-    struct free_list* next;
-    size_t size;
-};
+typedef __malloc_free_list free_list;
 
-static struct
-{
-    free_list* free;
-    size_t fragments;
-    void* top = &__heap_start;
-    void* limit = &__heap_end;
-} __heap;
+__malloc_heap __heap;
 
 void* _malloc_r(_reent* _, size_t size) { return _malloc_impl(size, false); }
 void _free_r(_reent* _, void* ptr) { free(ptr); }

targets/cortex-m/malloc_internal.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2024 triaxis s.r.o.
+ * Licensed under the MIT license. See LICENSE.txt file in the repository root
+ * for full license information.
+ *
+ * cortex-m/malloc_internal.h
+ *
+ * Exposes the internals of the Cortex malloc implementation for diagnostics
+ */
+
+#pragma once
+
+#include <base/base.h>
+
+#include <ld_symbols.h>
+
+struct __malloc_free_list
+{
+    struct __malloc_free_list* next;
+    size_t size;
+};
+
+struct __malloc_heap
+{
+    __malloc_free_list* free;
+    size_t fragments;
+    void* top = &__heap_start;
+    void* limit = &__heap_end;
+
+    constexpr size_t Total() { return &__heap_end - &__heap_start; }
+    constexpr size_t Committed() { return (char*)top - &__heap_start; }
+    constexpr size_t Fragments() { return fragments; }
+    constexpr size_t Used() { return Committed() - fragments; }
+    constexpr size_t ContiguousFree() { return (char*)limit - (char*)top; }
+    constexpr size_t Free() { return ContiguousFree() + fragments; }
+    constexpr size_t Once() { return &__heap_end - (char*)limit; }
+};
+
+extern __malloc_heap __heap;