[PATCH] Fix for PR26702: Emit .size for BSS variables on arm-eabi

[Kwok Cheung Yeung <kcy@codesourcery.com>]

This is a simple patch that ensures that a .size directive is emitted 
when space is allocated for a static variable in the BSS on bare-metal 
ARM targets. This allows other tools such as GDB to look up the size of 
the object correctly.

Before:

$ readelf -s pr26702.o

Symbol table '.symtab' contains 10 entries:
    Num:    Value  Size Type    Bind   Vis      Ndx Name
...
      6: 00000000     0 NOTYPE  LOCAL  DEFAULT    3 static_foo
...

After:

$ readelf -s pr26702.o

Symbol table '.symtab' contains 10 entries:
    Num:    Value  Size Type    Bind   Vis      Ndx Name
...
      6: 00000000     4 NOTYPE  LOCAL  DEFAULT    3 static_foo
...

The testsuite has been run with a i686-pc-linux-gnu hosted 
cross-compiler targetted at arm-none-eabi with no regressions.

Kwok


2015-03-30  Kwok Cheung Yeung  <kcy@codesourcery.com>

gcc/
	PR target/26702
	* config/arm/unknown-elf.h (ASM_OUTPUT_ALIGNED_DECL_LOCAL): Emit
	size of local.

gcc/testsuite/
	PR target/26702
	* gcc.target/arm/pr26702.c: New test.

Index: gcc/testsuite/gcc.target/arm/pr26702.c
===================================================================
--- gcc/testsuite/gcc.target/arm/pr26702.c	(revision 0)
+++ gcc/testsuite/gcc.target/arm/pr26702.c	(revision 0)
@@ -0,0 +1,4 @@
+/* { dg-do compile { target arm*-*-eabi* } } */
+/* { dg-final { scan-assembler "\\.size\[\\t \]+static_foo, 4" } } */
+int foo;
+static int static_foo;
Index: gcc/config/arm/unknown-elf.h
===================================================================
--- gcc/config/arm/unknown-elf.h	(revision 447549)
+++ gcc/config/arm/unknown-elf.h	(working copy)
@@ -81,6 +81,8 @@
        ASM_OUTPUT_ALIGN (FILE, floor_log2 (ALIGN / BITS_PER_UNIT));	\
        ASM_OUTPUT_LABEL (FILE, NAME);					\
        fprintf (FILE, "\t.space\t%d\n", SIZE ? (int)(SIZE) : 1);		\
+      fprintf (FILE, "\t.size\t%s, %d\n",				\
+	       NAME, SIZE ? (int)(SIZE) : 1);				\
      }									\
    while (0)