diff --git a/libc/bionic/debug_mapinfo.cpp b/libc/bionic/debug_mapinfo.cpp
new file mode 100644
index 0000000..174cc28
--- /dev/null
+++ b/libc/bionic/debug_mapinfo.cpp
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "dlmalloc.h"
+#include "debug_mapinfo.h"
+
+// 6f000000-6f01e000 rwxp 00000000 00:0c 16389419   /system/lib/libcomposer.so
+// 012345678901234567890123456789012345678901234567890123456789
+// 0         1         2         3         4         5
+
+static mapinfo_t* parse_maps_line(char* line) {
+  int len = strlen(line);
+
+  if (len < 1) return 0;
+  line[--len] = 0;
+
+  if (len < 50) return 0;
+  if (line[20] != 'x') return 0;
+
+  mapinfo_t* mi = static_cast<mapinfo_t*>(dlmalloc(sizeof(mapinfo_t) + (len - 47)));
+  if (mi == 0) return 0;
+
+  mi->start = strtoul(line, 0, 16);
+  mi->end = strtoul(line + 9, 0, 16);
+  mi->next = 0;
+  strcpy(mi->name, line + 49);
+
+  return mi;
+}
+
+__LIBC_HIDDEN__ mapinfo_t* mapinfo_create(int pid) {
+  struct mapinfo_t* milist = NULL;
+  char data[1024]; // Used to read lines as well as to construct the filename.
+  snprintf(data, sizeof(data), "/proc/%d/maps", pid);
+  FILE* fp = fopen(data, "r");
+  if (fp != NULL) {
+    while (fgets(data, sizeof(data), fp) != NULL) {
+      mapinfo_t* mi = parse_maps_line(data);
+      if (mi) {
+        mi->next = milist;
+        milist = mi;
+      }
+    }
+    fclose(fp);
+  }
+  return milist;
+}
+
+__LIBC_HIDDEN__ void mapinfo_destroy(mapinfo_t* mi) {
+  while (mi) {
+    mapinfo_t* del = mi;
+    mi = mi->next;
+    dlfree(del);
+  }
+}
+
+// Find the containing map info for the PC.
+__LIBC_HIDDEN__ const mapinfo_t* mapinfo_find(mapinfo_t* mi, unsigned pc, unsigned* rel_pc) {
+  *rel_pc = pc;
+  for (; mi != NULL; mi = mi->next) {
+    if ((pc >= mi->start) && (pc < mi->end)) {
+      *rel_pc -= mi->start;
+      return mi;
+    }
+  }
+  return NULL;
+}