pad .bss and .data so their sizes are always multiple of 4 bytes

CHANGELOG.md

@@ -13,6 +13,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   will go into Flash memory will be 4 byte aligned at the start and at the
   end. Which seems to be required (?) by Cortex-M0 devices.
 
+- .bss and .data are now padded so their sizes are multiple of 4 bytes. This
+  improves the output of `objdump`; before, the output showed "Address
+  0x20000004 is out of bounds".
+
 ## [v0.3.3] - 2017-07-14
 
 ### Changed

link.x

@@ -9,7 +9,7 @@ PROVIDE(_stack_start = ORIGIN(RAM) + LENGTH(RAM));
 
 SECTIONS
 {
-  .vector_table ORIGIN(FLASH) :
+  .vector_table ORIGIN(FLASH) : ALIGN(4)
   {
     /* Vector table */
     _svector_table = .;
@@ -45,18 +45,19 @@ SECTIONS
   {
     _sbss = .;
     *(.bss .bss.*);
-    _ebss = ALIGN(4);
+    . = ALIGN(4);
+    _ebss = .;
   } > RAM
 
   .data : ALIGN(4)
   {
+    _sidata = LOADADDR(.data);
     _sdata = .;
     *(.data .data.*);
-    _edata = ALIGN(4);
+    . = ALIGN(4);
+    _edata = .;
   } > RAM AT > FLASH
 
-  _sidata = LOADADDR(.data);
-
   /* The heap starts right after the .bss + .data section ends */
   _sheap = _edata;