sys/shell: cleanup the heap command approach

Replaces the special heap command approach of the lpc_common module with a more general heap command approach. Module lpc_common was already removed with PR RIOT-OS#2118. PR RIOT-OS#2118 integrated cpu/lpc_common code in cpu/lpc2387. With PR RIOT-OS#3530 special heap handling for cpu/lpc2387 was replaced by newlib memory management which uses _sbrk_r to allocate chunks from the heap. _sbrk_r uses _sheap and _eheap symbols that are defined in lpc2387.ld and can be used together with mallinfo function for heap statistics.

sys/newlib_syscalls_default/syscalls.c

@@ -27,6 +27,7 @@
 #include <unistd.h>
 #include <reent.h>
 #include <errno.h>
+#include <malloc.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -122,6 +123,24 @@ void *_sbrk_r(struct _reent *r, ptrdiff_t incr)
     return res;
 }
 
+/**
+ * @brief Print heap statistics
+ *
+ * If the CPU does not provide its own heap handling and heap_stats function,
+ * but instead uses the newlib_syscall_default function, this function outputs
+ * the heap statistics. If the CPU provides its own heap_stats function, it
+ * should define HAVE_HEAP_STATS in its cpu_conf.h file.
+ */
+#ifndef HAVE_HEAP_STATS
+__attribute__((weak)) void heap_stats(void)
+{
+    struct mallinfo minfo = mallinfo();
+    long int heap_size = &_eheap - &_sheap;
+    printf("heap: %ld (used %d, free %ld) [bytes]\n",
+           heap_size, minfo.uordblks, heap_size - minfo.uordblks);
+}
+#endif /* HAVE_HEAP_STATS */
+
 #endif /*__mips__*/
 
 /**

sys/shell/commands/Makefile

@@ -11,6 +11,9 @@ endif
 ifneq (,$(filter ps,$(USEMODULE)))
   SRC += sc_ps.c
 endif
+ifneq (,$(filter heap_cmd,$(USEMODULE)))
+  SRC += sc_heap.c
+endif
 ifneq (,$(filter sht1x,$(USEMODULE)))
   SRC += sc_sht1x.c
 endif

sys/shell/commands/sc_heap.c

@@ -18,14 +18,24 @@
  * @}
  */
 
+#include "cpu_conf.h"
+
+#if defined(MODULE_NEWLIB_SYSCALLS_DEFAULT) || defined (HAVE_HEAP_STATS)
 extern void heap_stats(void);
+#else
+#include <stdio.h>
+#endif
 
 int _heap_handler(int argc, char **argv)
 {
     (void) argc;
     (void) argv;
 
+#if defined(MODULE_NEWLIB_SYSCALLS_DEFAULT) || defined (HAVE_HEAP_STATS)
     heap_stats();
-
     return 0;
+#else
+    printf("heap statistics are not supported for %s cpu\n", RIOT_CPU);
+    return 1;
+#endif
 }

sys/shell/commands/shell_commands.c

@@ -29,7 +29,7 @@ extern int _reboot_handler(int argc, char **argv);
 extern int _id_handler(int argc, char **argv);
 #endif
 
-#ifdef MODULE_LPC_COMMON
+#ifdef MODULE_HEAP_CMD
 extern int _heap_handler(int argc, char **argv);
 #endif
 
@@ -168,8 +168,8 @@ const shell_command_t _shell_command_list[] = {
 #ifdef MODULE_CONFIG
     {"id", "Gets or sets the node's id.", _id_handler},
 #endif
-#ifdef MODULE_LPC_COMMON
-    {"heap", "Shows the heap state for the LPC2387 on the command shell.", _heap_handler},
+#ifdef MODULE_HEAP_CMD
+    {"heap", "Prints heap statistics.", _heap_handler},
 #endif
 #ifdef MODULE_PS
     {"ps", "Prints information about running threads.", _ps_handler},