Add a simple memory management wrapper.

* lib/jit_memory.c: Implement a simple memory allocation wrapper
	to allow overriding calls to malloc/calloc/realloc/free, as well
	as ensuring all memory containing pointers is zero or points to
	allocated memory.

	* include/lightning.h, include/lightning/jit_private.h: Definitions
	for the memory allocation wrapper.

	* lib/Makefile.am: Update for new jit_memory.c file.

	* lib/jit_arm.c, lib/jit_disasm.c, lib/jit_mips.c, lib/jit_note.c,
	lib/jit_ppc.c, lib/jit_sparc.c, lib/jit_x86.c, lib/lightning.c:
	Use the new memory allocation wrapper code.

lib/jit_memory.c

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2013  Free Software Foundation, Inc.
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Authors:
+ *	Paulo Cesar Pereira de Andrade
+ */
+
+#include <lightning.h>
+#include <lightning/jit_private.h>
+
+/*
+ * Prototypes
+ */
+static void *jit_default_alloc_func(size_t);
+static void *jit_default_realloc_func(void*, size_t);
+static void jit_default_free_func(void *);
+
+/*
+ * Initialization
+ */
+static jit_alloc_func_ptr jit_alloc_ptr = jit_default_alloc_func;
+static jit_realloc_func_ptr jit_realloc_ptr = jit_default_realloc_func;
+static jit_free_func_ptr jit_free_ptr = jit_default_free_func;
+
+/*
+ * Implementation
+ */
+void
+jit_set_memory_functions(jit_alloc_func_ptr alloc_ptr,
+			 jit_realloc_func_ptr realloc_ptr,
+			 jit_free_func_ptr free_ptr)
+{
+    if (alloc_ptr == NULL)
+	alloc_ptr = jit_default_alloc_func;
+    if (realloc_ptr == NULL)
+	realloc_ptr = jit_default_realloc_func;
+    if (free_ptr == NULL)
+	free_ptr = jit_default_free_func;
+    jit_alloc_ptr = alloc_ptr;
+    jit_realloc_ptr = realloc_ptr;
+    jit_free_ptr = free_ptr;
+}
+
+void
+jit_get_memory_functions(jit_alloc_func_ptr *alloc_ptr,
+			 jit_realloc_func_ptr *realloc_ptr,
+			 jit_free_func_ptr *free_ptr)
+{
+    *alloc_ptr = jit_alloc_ptr;
+    *realloc_ptr = jit_realloc_ptr;
+    *free_ptr = jit_free_ptr;
+}
+
+void
+jit_alloc(jit_pointer_t *ptr, jit_word_t size)
+{
+    *ptr = (*jit_alloc_ptr)(size);
+    memset(*ptr, 0, size);
+}
+
+void
+jit_realloc(jit_pointer_t *ptr, jit_word_t old_size, jit_word_t new_size)
+{
+    *ptr = (*jit_realloc_ptr)(*ptr, new_size);
+    if (old_size < new_size)
+	memset((jit_int8_t*)*ptr + old_size, 0, new_size - old_size);
+}
+
+void
+jit_free(jit_pointer_t *ptr)
+{
+    (*jit_free_ptr)(*ptr);
+    *ptr = NULL;
+}
+
+static void *
+jit_default_alloc_func(size_t size)
+{
+    return (malloc(size));
+}
+
+static void *
+jit_default_realloc_func(void *ptr, size_t size)
+{
+    return (realloc(ptr, size));
+}
+
+static void
+jit_default_free_func(void *ptr)
+{
+    free(ptr);
+}