Concept: druntime getting rid of libc dependency

druntime/mak/COPY

@@ -23,6 +23,7 @@ COPY=\
 	$(IMPDIR)\core\memory.d \
 	$(IMPDIR)\core\runtime.d \
 	$(IMPDIR)\core\simd.d \
+	$(IMPDIR)\core\system.d \
 	$(IMPDIR)\core\time.d \
 	$(IMPDIR)\core\vararg.d \
 	$(IMPDIR)\core\volatile.d \

druntime/mak/SRCS

@@ -17,6 +17,7 @@ SRCS=\
 	src\core\memory.d \
 	src\core\runtime.d \
 	src\core\simd.d \
+	src\core\system.d \
 	src\core\time.d \
 	src\core\vararg.d \
 	src\core\volatile.d \

druntime/src/core/gc/registry.d

@@ -60,9 +60,9 @@ alias GCThreadInitFunction = void function(ThreadBase base) nothrow @nogc;
 void registerGCFactory(string name, GCFactory factory,
         GCThreadInitFunction threadInit = null) nothrow @nogc
 {
-    import core.stdc.stdlib : realloc;
+    import core.system : Mem;
 
-    auto ptr = cast(Entry*)realloc(entries.ptr, (entries.length + 1) * Entry.sizeof);
+    auto ptr = cast(Entry*) Mem.reallocate(entries.ptr, (entries.length + 1) * Entry.sizeof);
     entries = ptr[0 .. entries.length + 1];
     entries[$ - 1] = Entry(name, factory, threadInit);
 }

druntime/src/core/internal/gc/bits.d

@@ -11,7 +11,7 @@ import core.internal.gc.os;
 
 import core.bitop;
 import core.exception : onOutOfMemoryError;
-import core.stdc.stdlib : calloc, free;
+import core.system : Mem;
 import core.stdc.string : memcpy, memset;
 
 // use version gcbitsSingleBitOperation to disable optimizations that use
@@ -38,7 +38,7 @@ struct GCBits
         if (data)
         {
             if (!AllocSupportsShared || !share)
-                free(data);
+                Mem.free(data);
             else static if (AllocSupportsShared)
                 os_mem_unmap_shared(data, nwords * data[0].sizeof);
             else
@@ -51,7 +51,7 @@ struct GCBits
     {
         this.nbits = nbits;
         if (!AllocSupportsShared || !share)
-            data = cast(typeof(data[0])*)calloc(nwords, data[0].sizeof);
+            data = cast(typeof(data[0])*) Mem.allocateBlank(nwords * data[0].sizeof);
         else static if (AllocSupportsShared)
             data = cast(typeof(data[0])*)os_mem_map_shared(nwords * data[0].sizeof); // Allocate as MAP_SHARED
         else

druntime/src/core/runtime.d

@@ -209,7 +209,7 @@ struct Runtime
      */
     static void* loadLibrary()(const scope char[] name)
     {
-        import core.stdc.stdlib : free, malloc;
+        import core.system : Mem;
         version (Windows)
         {
             import core.sys.windows.winnls : CP_UTF8, MultiByteToWideChar;
@@ -222,9 +222,9 @@ struct Runtime
             if (len == 0)
                 return null;
 
-            auto buf = cast(WCHAR*)malloc((len+1) * WCHAR.sizeof);
+            auto buf = cast(WCHAR*) Mem.allocate((len+1) * WCHAR.sizeof);
             if (buf is null) return null;
-            scope (exit) free(buf);
+            scope (exit) Mem.free(buf);
 
             len = MultiByteToWideChar(
                 CP_UTF8, 0, name.ptr, cast(int)name.length, buf, len);
@@ -240,9 +240,9 @@ struct Runtime
             /* Need a 0-terminated C string for the dll name
              */
             immutable len = name.length;
-            auto buf = cast(char*)malloc(len + 1);
+            auto buf = cast(char*) Mem.allocate(len + 1);
             if (!buf) return null;
-            scope (exit) free(buf);
+            scope (exit) Mem.free(buf);
 
             buf[0 .. len] = name[];
             buf[len] = 0;

druntime/src/core/system.d

@@ -0,0 +1,20 @@
+///
+module core.system;
+
+package:
+
+struct Mem
+{
+    import core.stdc.stdlib;
+
+    alias allocate = malloc;
+    alias reallocate = realloc;
+    alias free = core.stdc.stdlib.free;
+
+    static void* allocateBlank(size_t size) nothrow @nogc
+    {
+        ubyte* p = cast(ubyte*) allocate(size);
+        p[0 .. size] = 0;
+        return cast(void*) p;
+    }
+}