[Bug c/11446] [3.4] Incompatibilty with alignment of structures between 3.3 and 3.4 CVS

["janis187 at us dot ibm dot com" <gcc-bugzilla at gcc dot gnu dot org>]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11446


janis187 at us dot ibm dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at redhat dot com


------- Additional Comments From janis187 at us dot ibm dot com  2003-07-31 23:18 -------
The sizes and alignments of the structs in PR 11446 changed with this
patch:

--- gcc/gcc/ChangeLog ---

2003-04-03  Jason Merrill  <jason@redhat.com>

        * stor-layout.c (do_type_align): New fn, split out from...
        (layout_decl): ...here.  Do all alignment calculations for
        FIELD_DECLs here.
        (update_alignment_for_field): Not here.
        (start_record_layout, debug_rli): Remove unpadded_align.
        * tree.h (struct record_layout_info_s): Remove unpadded_align.
        * c-decl.c (finish_enum): Don't set DECL_SIZE, DECL_ALIGN
        or DECL_MODE on the CONST_DECLs.
        (finish_struct): Don't mess with DECL_ALIGN.

--- gcc/gcc/cp/ChangeLog ---

2003-04-03  Jason Merrill  <jason@redhat.com>

        * class.c (build_vtable): Set DECL_ALIGN here.
        (get_vtable_decl): Not here.
        (layout_vtable_decl): Or here.
        (create_vtable_ptr): Or here.
        (layout_class_type): Or here.
        (check_bitfield_decl): Don't mess with field alignment.

I used the following test on i686-pc-linux-gnu and watched for the size
of b2 to become 32:

------------------------------------------------------------------
struct A2_m_inner_p_outer {
  double d;
} __attribute__ ((aligned));

struct B2_m_inner_p_outer {
  char c;
  struct A2_m_inner_p_outer a2;
} __attribute__ ((packed));

struct B2_m_inner_p_outer b2 = { 1, { 2.0 } };

struct B2_m_inner_p_outer a2[2] = { { 1, { 2.0 } }, { 2, { 3.0 } } };
------------------------------------------------------------------

Here's the definition of b2 before and after the patch:

 .globl b2
        .data
+       .align 16
        .type   b2, @object
-       .size   b2, 17
+       .size   b2, 32
 b2:
        .byte   1
+       .zero   15
        .long   0
        .long   1073741824
        .zero   8

I don't know what the expected sizes and alignments are; Jason, is this
change expected?