modlib: Move modlib_allocbuffer to modlib_sectname and modlib_symname

it's better to allocate the buffer just before really use it.

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

libs/libc/modlib/modlib_bind.c

@@ -811,17 +811,6 @@ int modlib_bind(FAR struct module_s *modp,
       return ret;
     }
 
-  /* Allocate an I/O buffer.  This buffer is used by mod_symname() to
-   * accumulate the variable length symbol name.
-   */
-
-  ret = modlib_allocbuffer(loadinfo);
-  if (ret < 0)
-    {
-      berr("ERROR: modlib_allocbuffer failed: %d\n", ret);
-      return -ENOMEM;
-    }
-
   /* Process relocations in every allocated section */
 
   for (i = 1; i < loadinfo->ehdr.e_shnum; i++)

libs/libc/modlib/modlib_sections.c

@@ -73,6 +73,17 @@ static inline int modlib_sectname(FAR struct mod_loadinfo_s *loadinfo,
       return -EINVAL;
     }
 
+  /* Allocate an I/O buffer.  This buffer is used by modlib_sectname() to
+   * accumulate the variable length symbol name.
+   */
+
+  ret = modlib_allocbuffer(loadinfo);
+  if (ret < 0)
+    {
+      berr("ERROR: modlib_allocbuffer failed: %d\n", ret);
+      return -ENOMEM;
+    }
+
   /* Get the section name string table section header */
 
   shstr = &loadinfo->shdr[shstrndx];

libs/libc/modlib/modlib_symbols.c

@@ -109,6 +109,17 @@ static int modlib_symname(FAR struct mod_loadinfo_s *loadinfo,
       return -ESRCH;
     }
 
+  /* Allocate an I/O buffer.  This buffer is used by mod_symname() to
+   * accumulate the variable length symbol name.
+   */
+
+  ret = modlib_allocbuffer(loadinfo);
+  if (ret < 0)
+    {
+      berr("ERROR: modlib_allocbuffer failed: %d\n", ret);
+      return -ENOMEM;
+    }
+
   offset = sh_offset + sym->st_name;
 
   /* Loop until we get the entire symbol name into memory */