DImode is aligned at 4 byte according to i386 psABI. This 4.4 patch
http://gcc.gnu.org/ml/gcc-patches/2008-02/msg00184.html
will use 4byte alignment for DImode. But Ada doesn't follow i386 psABI.
validate_alignment in ada/decl.c does
new_align = UI_To_Int (alignment);
...
align = MAX (align, new_align == 0 ? 1 : new_align * BITS_PER_UNIT);
It changes DImode alignment from 32bit to 64bit and turns DImode integer
into a DImode record. As the result, Ada fails to compile s-pack33.adb:
s-pack33.adb:52:49: size for "E0" too small, minimum allowed is 64
s-pack33.adb:53:49: size for "E1" too small, minimum allowed is 64
s-pack33.adb:54:49: size for "E2" too small, minimum allowed is 64
s-pack33.adb:55:49: size for "E3" too small, minimum allowed is 64
s-pack33.adb:56:49: size for "E4" too small, minimum allowed is 64
s-pack33.adb:57:49: size for "E5" too small, minimum allowed is 64
s-pack33.adb:58:49: size for "E6" too small, minimum allowed is 64
s-pack33.adb:59:49: size for "E7" too small, minimum allowed is 64
s-pack33.adb:62:30: size for "Cluster" too small, minimum allowed is 512
because validate_size has
(gdb) call debug_tree (size)
<integer_cst 0xb7d0d4d0 type <integer_type 0xb7cf8068 bit_size_type> constant
invariant 33>
(gdb) call debug_tree (type_size)
<integer_cst 0xb7ceb738 type <integer_type 0xb7cf8068 bit_size_type> constant
invariant visited 64>
(gdb) call debug_tree (gnu_type)
<record_type 0xb7d0ed00 system__pack_33__bits_33___PAD sizes-gimplified
asm_written visited type_5 DI
size <integer_cst 0xb7ceb738 type <integer_type 0xb7cf8068 bit_size_type>
constant invariant visited 64>
unit size <integer_cst 0xb7ceb754 type <integer_type 0xb7cf8000 long int>
constant invariant visited 8>
align 64 symtab -1210166256 alias set -1 canonical type 0xb7d0ed00
fields <field_decl 0xb7d052e0 F
type <integer_type 0xb7d0ec98 system__pack_33__bits_33 type
<integer_type 0xb7d0ec30 system__pack_33__bits_33___UMT>
sizes-gimplified asm_written visited unsigned type_2 DI size
<integer_cst 0xb7ceb738 64> unit size <integer_cst 0xb7ceb754 8>
align 32 symtab -1210166464 alias set -1 canonical type 0xb7d0ec98
precision 64 min <integer_cst 0xb7d0d364 0> max <integer_cst 0xb7d0d3f0
0x1ffffffff>>
unsigned decl_3 decl_5 DI file s-pack33.ads line 6 col 9 size
<integer_cst 0xb7ceb738 64> unit size <integer_cst 0xb7ceb754 8>
align 32 offset_align 128
offset <integer_cst 0xb7ceb968 constant invariant visited 0>
bit offset <integer_cst 0xb7ceb984 constant invariant 0> context
<record_type 0xb7d0ed00 system__pack_33__bits_33___PAD>> Ada size <integer_cst
0xb7ceb738 64>
chain <type_decl 0xb7d0edd0 system__pack_33__bits_33___PAD>>
(gdb)
Before my patch, validate_size has
(gdb) call debug_tree (size)
<integer_cst 0xb7c9f444 type <integer_type 0xb7c8a068 bit_size_type> constant
invariant 33>
(gdb)
<integer_cst 0xb7c9f444 type <integer_type 0xb7c8a068 bit_size_type> constant
invariant 33>
(gdb) call debug_tree (type_size)
<integer_cst 0xb7c9f444 type <integer_type 0xb7c8a068 bit_size_type> constant
invariant 33>
(gdb) call debug_tree (gnu_type)
<integer_type 0xb7ca0c98 system__pack_33__bits_33
type <integer_type 0xb7ca0c30 system__pack_33__bits_33___UMT public
unsigned type_1 DI
size <integer_cst 0xb7c7d738 constant invariant visited 64>
unit size <integer_cst 0xb7c7d754 constant invariant visited 8>
align 64 symtab -1208441944 alias set -1 canonical type 0xb7ca0c30
precision 64 min <integer_cst 0xb7c9f364 0> max <integer_cst 0xb7c9894c -1>
modulus <integer_cst 0xb7c9f3d4 constant invariant 0x200000000>>
sizes-gimplified visited unsigned type_2 DI size <integer_cst 0xb7c7d738
64> unit size <integer_cst 0xb7c7d754 8>
align 64 symtab -1208442048 alias set -1 canonical type 0xb7ca0c98
precision 64 min <integer_cst 0xb7c9f364 0> max <integer_cst 0xb7c9f3f0
0x1ffffffff>
RM size <integer_cst 0xb7c9f444 type <integer_type 0xb7c8a068
bit_size_type> constant invariant 33>>
(gdb)
--
Summary: Ada doesn't follow i386 psABI
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ada
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: hjl dot tools at gmail dot com
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35186
