diff --git a/mach/proto/mcg/map.c b/mach/proto/mcg/map.c
deleted file mode 100644
index 228cf8bcc..000000000
--- a/mach/proto/mcg/map.c
+++ /dev/null
@@ -1,58 +0,0 @@
-#include "mcg.h"
-
-static void extend(struct map_node** map, int* count, int* max)
-{
-	if (*count == *max)
-	{
-		int newmax = (*max == 0) ? 8 : (*max * 2);
-		struct map_node* newmap = realloc(*map, newmax * sizeof(struct map_node));
-		if (!newmap)
-			fatal("memory allocation failure");
-
-		*max = newmax;
-		*map = newmap;
-	}
-}
-
-void map_set(struct map_node** map, int* count, int* max, void* left, void* right)
-{
-	int i;
-	struct map_node* node;
-
-	for (i=0; i<*count; i++)
-	{
-		node = &(*map)[i];
-		if (node->left == left)
-		{
-			node->right = right;
-			return;
-		}
-	}
-
-	extend(map, count, max);
-	node = &(*map)[*count];
-	node->left = left;
-	node->right = right;
-	(*count)++;
-}
-
-void map_add(struct map_node** map, int* count, int* max, void* left, void* right)
-{
-	int i;
-	struct map_node* node;
-
-	for (i=0; i<*count; i++)
-	{
-		node = &(*map)[i];
-		if ((node->left == left) && (node->right == right))
-			return;
-	}
-
-	extend(map, count, max);
-	node = &(*map)[*count];
-	node->left = left;
-	node->right = right;
-	(*count)++;
-}
-
-/* vim: set sw=4 ts=4 expandtab : */
diff --git a/mach/proto/mcg/map.h b/mach/proto/mcg/map.h
deleted file mode 100644
index bf9d9e8e3..000000000
--- a/mach/proto/mcg/map.h
+++ /dev/null
@@ -1,26 +0,0 @@
-#ifndef MAP_H
-#define MAP_H
-
-struct map_node
-{
-	void* left;
-	void* right;
-};
-
-#define _MAP(MODIFIER, NAME) \
-	MODIFIER struct map_node* NAME; \
-	MODIFIER int NAME##_count; \
-	MODIFIER int NAME##_max
-
-#define MAP(NAME) _MAP(, NAME)
-#define STATICMAP(NAME) _MAP(static, NAME)
-
-#define MAP_SET(MAP, LEFT, RIGHT) \
-	map_set(&MAP, &MAP##_count, &MAP##_max, LEFT, RIGHT)
-
-extern void map_set(struct map_node** map, int* count, int* max, void* left, void* right);
-extern void map_add(struct map_node** map, int* count, int* max, void* left, void* right);
-
-#endif
-
-
diff --git a/mach/proto/mcg/pass_convertstackops.c b/mach/proto/mcg/pass_convertstackops.c
index fd18ab67b..adbe25068 100644
--- a/mach/proto/mcg/pass_convertstackops.c
+++ b/mach/proto/mcg/pass_convertstackops.c
@@ -1,6 +1,6 @@
 #include "mcg.h"
 
-STATICMAP(graph);
+static MAPOF(struct basicblock, struct basicblock) graph;
 static ARRAYOF(struct ir) pops;
 static ARRAYOF(struct ir) pushes;
 
@@ -46,7 +46,7 @@ static bool collect_outputs_cb(struct ir* ir, void* user)
     struct basicblock* caller = user;
 
     if (ir->opcode == IR_BLOCK)
-        MAP_SET(graph, caller, ir->u.bvalue);
+        map_addp(&graph, caller, ir->u.bvalue);
     return false;
 }
 
@@ -54,7 +54,7 @@ static void make_bb_graph(struct procedure* proc)
 {
     int i, j;
 
-    graph_count = 0;
+    graph.count = 0;
     for (i=0; i<proc->blocks.count; i++)
     {
         struct basicblock* bb = proc->blocks.item[i];
@@ -78,11 +78,11 @@ static void convert_block(struct procedure* proc, struct basicblock* bb)
         /* Abort unless *every* successor block of this one starts with a pop
          * of the same size... */
 
-        for (i=0; i<graph_count; i++)
+        for (i=0; i<graph.count; i++)
         {
-            if (graph[i].left == bb)
+            if (graph.item[i].left == bb)
             {
-                struct basicblock* outbb = graph[i].right;
+                struct basicblock* outbb = graph.item[i].right;
 
                 ir = get_first_pop(outbb);
                 if (!ir || (ir->size != lastpush->size))
@@ -92,11 +92,11 @@ static void convert_block(struct procedure* proc, struct basicblock* bb)
                 /* Also abort unless *every* predecessor block of the one we've
                  * just found *also* ends in a push of the same size. */
 
-                for (j=0; j<graph_count; j++)
+                for (j=0; j<graph.count; j++)
                 {
-                    if (graph[j].right == outbb)
+                    if (graph.item[j].right == outbb)
                     {
-                        struct basicblock* inbb = graph[j].left;
+                        struct basicblock* inbb = graph.item[j].left;
 
                         ir = get_last_push(inbb);
                         if (!ir || (ir->size != lastpush->size))
diff --git a/modules/src/data/build.lua b/modules/src/data/build.lua
index 7250f4f72..f9af7c519 100644
--- a/modules/src/data/build.lua
+++ b/modules/src/data/build.lua
@@ -6,4 +6,3 @@ clibrary {
 	},
 }
 
-
diff --git a/modules/src/data/map.c b/modules/src/data/map.c
new file mode 100644
index 000000000..d75284762
--- /dev/null
+++ b/modules/src/data/map.c
@@ -0,0 +1,58 @@
+#include <stdlib.h>
+#include <stdbool.h>
+#include "map.h"
+
+static void append(void* mapp, void* left, void* right)
+{
+    struct map* map = mapp;
+    struct map_node* node;
+
+	if (map->count == map->max)
+	{
+		int newmax = (map->max == 0) ? 8 : (map->max * 2);
+		struct map_node* newarray = realloc(map->item, newmax * sizeof(*newarray));
+
+		map->max = newmax;
+		map->item = newarray;
+	}
+
+    node = &map->item[map->count];
+    map->count++;
+
+    node->left = left;
+    node->right = right;
+}
+
+void map_putp(void* mapp, void* left, void* right)
+{
+    struct map* map = mapp;
+    int i;
+
+    for (i=0; i<map->count; i++)
+    {
+        struct map_node* node = &map->item[i];
+        if (node->left == left)
+        {
+            node->right = right;
+            return;
+        }
+    }
+
+    append(map, left, right);
+}
+
+void map_addp(void* mapp, void* left, void* right)
+{
+    struct map* map = mapp;
+    int i;
+
+    for (i=0; i<map->count; i++)
+    {
+        struct map_node* node = &map->item[i];
+        if ((node->left == left) && (node->right == right))
+            return;
+    }
+
+    append(map, left, right);
+}
+
diff --git a/modules/src/data/map.h b/modules/src/data/map.h
new file mode 100644
index 000000000..859618bd7
--- /dev/null
+++ b/modules/src/data/map.h
@@ -0,0 +1,30 @@
+#ifndef MAP_H
+#define MAP_H
+
+struct map_node
+{
+	void* left;
+	void* right;
+};
+
+/* Danger, Will Robinson! The type and the macro must be compatible. */
+
+struct map
+{
+	struct map_node* item;
+	int count;
+	int max;
+};
+
+#define MAPOF(LEFT, RIGHT) \
+	struct { \
+		struct { LEFT* left; RIGHT* right; }* item; \
+		int count; \
+		int max; \
+	}
+
+extern void map_putp(void* map, void* left, void* right);
+extern void map_addp(void* map, void* left, void* right);
+
+#endif
+