------- Additional Comments From mcvick_e at iname dot com 2005-08-24 15:44
-------
Here is a short program that duplicates the problem.
------------------ test.cc ------------------------
struct foo {
char bar1;
char bar2;
char bar3;
};
class bar2 {
private:
static foo myFubarStruct;
public:
static void fbs(foo fubarStruct);
};
foo bar2::myFubarStruct;
class bar1 {
private:
int rVal1;
int rVal2;
public:
void doFoo(void);
};
void bar1::doFoo(void) {
foo barStruct;
barStruct.bar1 = 'A';
barStruct.bar2 = 'B';
barStruct.bar3 = 'C';
bar2::fbs(barStruct);
}
void bar2::fbs(foo fubarStruct) {
myFubarStruct = fubarStruct;
}
int main(int argc, char **argv) {
bar1 baar;
baar.doFoo();
return (0);
}
------------------ end of test.cc ------------------------------
The test app was just compiled to object code as shown below with the -mstrict-
align option.
(2)> ppcg++ -mstrict-align -c test.cc
Then an objdump was done to dump the assembly (shown below)
(3)> ppcobjdump -C -S test.o
test.o: file format elf32-powerpc
Disassembly of section .text:
00000000 <bar2::fbs(foo)>:
0: 94 21 ff f0 stwu r1,-16(r1)
4: 93 e1 00 0c stw r31,12(r1)
8: 7c 3f 0b 78 mr r31,r1
c: 7c 6b 1b 78 mr r11,r3
10: 3d 20 00 00 lis r9,0
14: 39 29 00 00 addi r9,r9,0
18: 88 0b 00 00 lbz r0,0(r11)
1c: 89 4b 00 01 lbz r10,1(r11)
20: 89 6b 00 02 lbz r11,2(r11)
24: 98 09 00 00 stb r0,0(r9)
28: 99 49 00 01 stb r10,1(r9)
2c: 99 69 00 02 stb r11,2(r9)
30: 81 61 00 00 lwz r11,0(r1)
34: 83 eb ff fc lwz r31,-4(r11)
38: 7d 61 5b 78 mr r1,r11
3c: 4e 80 00 20 blr
00000040 <bar1::doFoo()>:
40: 94 21 ff c8 stwu r1,-56(r1)
44: 7c 08 02 a6 mflr r0
48: 93 e1 00 34 stw r31,52(r1)
4c: 90 01 00 3c stw r0,60(r1)
50: 7c 3f 0b 78 mr r31,r1
54: 90 7f 00 18 stw r3,24(r31)
58: 38 00 00 41 li r0,65
5c: 98 1f 00 0b stb r0,11(r31)
60: 38 00 00 42 li r0,66
64: 98 1f 00 0c stb r0,12(r31)
68: 38 00 00 43 li r0,67
6c: 98 1f 00 0d stb r0,13(r31)
70: 88 1f 00 0b lbz r0,11(r31)
74: 89 3f 00 0c lbz r9,12(r31)
78: 89 7f 00 0d lbz r11,13(r31)
7c: 98 1f 00 08 stb r0,8(r31)
80: 99 3f 00 09 stb r9,9(r31)
84: 99 7f 00 0a stb r11,10(r31)
88: 88 1f 00 08 lbz r0,8(r31)
8c: a1 3f 00 09 lhz r9,9(r31) <--- Odd alignment
90: 98 1f 00 20 stb r0,32(r31)
94: b1 3f 00 21 sth r9,33(r31) <--- Odd alignment
98: 38 1f 00 20 addi r0,r31,32
9c: 7c 03 03 78 mr r3,r0
a0: 48 00 00 01 bl a0 <bar1::doFoo()+0x60>
a4: 81 61 00 00 lwz r11,0(r1)
a8: 80 0b 00 04 lwz r0,4(r11)
ac: 7c 08 03 a6 mtlr r0
b0: 83 eb ff fc lwz r31,-4(r11)
b4: 7d 61 5b 78 mr r1,r11
b8: 4e 80 00 20 blr
000000bc <main>:
bc: 94 21 ff d8 stwu r1,-40(r1)
c0: 7c 08 02 a6 mflr r0
c4: 93 e1 00 24 stw r31,36(r1)
c8: 90 01 00 2c stw r0,44(r1)
cc: 7c 3f 0b 78 mr r31,r1
d0: 90 7f 00 18 stw r3,24(r31)
d4: 90 9f 00 1c stw r4,28(r31)
d8: 48 00 00 01 bl d8 <main+0x1c>
dc: 38 7f 00 08 addi r3,r31,8
e0: 48 00 00 01 bl e0 <main+0x24>
e4: 38 00 00 00 li r0,0
e8: 7c 03 03 78 mr r3,r0
ec: 81 61 00 00 lwz r11,0(r1)
f0: 80 0b 00 04 lwz r0,4(r11)
f4: 7c 08 03 a6 mtlr r0
f8: 83 eb ff fc lwz r31,-4(r11)
fc: 7d 61 5b 78 mr r1,r11
100: 4e 80 00 20 blr
(4)>
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23539
