[proposed but not yet applied patch for PR28865 (PR39383 and PR56880 are dups) <mikpe@it.uu.se>]

Date: Wed, 22 Apr 2009 18:13:42 -0500 (CDT)
From: "Anmol P dot  Paralkar" <anmol at freescale dot com>
Subject: PATCH RFA: Fix for PR 39383 for generic ELF systems.
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>

Hello,

  Please find attached, a fix for PR 39383 in the case of generic ELF systems
  and a test-case for inclusion in the test-suite.

  Per Comment #6 in the PR, the .size assembler directive emitted ought to
  contain the "true" size of the object (when the object is of type struct
  containing a flexible array - using the size of the type is going to be
  off). The fix involves changing the definition of the ASM_DECLARE_OBJECT_NAME
  macro to use the size of the variable's initializer instead of the type of
  the variable.

  The fixed GCC was bootstrapped and tested on a PowerBook G4 (7447A altivec
  supported), running Linux 2.6.27.5-117.fc10.ppc (compared post-fix relative
  to pre-fix for each of: gcc, g++, libgomp, libmudflap, objc, gfortran, libffi,
  libjava, libstdc++ - there were no regressions - please let me know in case
  you wish to see the summaries/logs) in native configuration:
  powerpc-unknown-linux-gnu

  This is my zeroeth attempt to contribute to GCC; any advice (especially, if the
  ASM_FINISH_DECLARE_OBJECT macro needs the same change as well) is gratefully
  received.

  Thank you.

Sincerely,
Anmol P. Paralkar

2009-04-22  Anmol P. Paralkar  <anmol@freescale.com>

	PR c/39383
	* config/elfos.h (ASM_DECLARE_OBJECT_NAME): Use the size of the
	variable's initializer instead of the size of its type.

2009-04-22  Anmol P. Paralkar  <anmol@freescale.com>

	PR c/39383
	* gcc.dg/pr39383.c: New testcase.

--- gcc-4.7.3/gcc/config/elfos.h.~1~	2011-11-14 17:55:56.000000000 +0100
+++ gcc-4.7.3/gcc/config/elfos.h	2013-04-20 12:52:04.129290034 +0200
@@ -316,7 +316,7 @@ see the files COPYING3 and COPYING.RUNTI
 	  && (DECL) && DECL_SIZE (DECL))				\
 	{								\
 	  size_directive_output = 1;					\
-	  size = int_size_in_bytes (TREE_TYPE (DECL));			\
+	  size = tree_low_cst (DECL_SIZE_UNIT (DECL), 1);		\
 	  ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);			\
 	}								\
 									\
--- gcc-4.7.3/gcc/testsuite/gcc.dg/pr39383.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.7.3/gcc/testsuite/gcc.dg/pr39383.c	2013-04-20 12:52:04.129290034 +0200
@@ -0,0 +1,16 @@
+/* Verify that when a struct has a flexible array member,
+   the size in the emitted .size assembler directive for
+   a statically initialized object (of that type) is based
+   on the actual size of the object (as determined by its
+   initializer) and not on the type of the object. */
+
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+struct text
+{
+  char len;
+  char txt[];
+} vowels = { 5, { 'a', 'e', 'i', 'o', 'u' } };
+
+/* { dg-final { scan-assembler "\.size\[ \t\]+vowels,\[ \t\]+6" } } */