Hi, I've run into a piece of code on ppc405 that does the wrong thing when a function is automatically inlined. I don't really do ppc asm so I haven't been able to isolate what exactly the problem is, but the code blatantly takes the wrong branch.
The toolchain I'm using is a cross compiler from x86 to ppc. The target
is a 405gp. I built this gcc-3.4.5/binutils-2.15/glibc-2.3.6 compiler
using crosstools-0.42
Reading specs from
/home/mort/src/targa/powerpc-linux/gcc-3.4.5-glibc-2.3.6/powerpc-405-linux-gnu/bin/../lib/gcc/powerpc-405-linux-gnu/3.4.5/specs
Configured with:
/home/mort/src/crosstool-0.42/build/powerpc-405-linux-gnu/gcc-3.4.5-glibc-2.3.6/gcc-3.4.5/configure
--target=powerpc-405-linux-gnu --host=i686-host_pc-linux-gnu
--prefix=/opt/targa/local/powerpc-linux/gcc-3.4.5-glibc-2.3.6/powerpc-405-linux-gnu
--with-cpu=405 --enable-cxx-flags=-mcpu=405
--with-headers=/opt/targa/local/powerpc-linux/gcc-3.4.5-glibc-2.3.6/powerpc-405-linux-gnu/powerpc-405-linux-gnu/include
--with-local-prefix=/opt/targa/local/powerpc-linux/gcc-3.4.5-glibc-2.3.6/powerpc-405-linux-gnu/powerpc-405-linux-gnu
--disable-nls --enable-threads=posix --enable-symvers=gnu
--enable-__cxa_atexit --enable-languages=c,c++ --enable-shared --enable-c99
--enable-long-long
Thread model: posix
gcc version 3.4.5
The problem I'm having is when running the CPU post test on u-boot
1.1.4. Specifically, in the branch tests. While doing the first branch
conditional test the computer incorrectly takes the "if (link)" branch
in u-boot/post/cpu/b.c::cpu_post_test_bc()
--- a/post/cpu/b.c
+++ b/post/cpu/b.c
@@ -84,10 +84,14 @@ static int cpu_post_test_bc (ulong cmd,
}
if (ret == 0)
{
- if (link)
+ printf("link = %d\n", link);
+ if (link)
ret = lr == (ulong) code + 24 ? 0 : -1;
else
ret = lr == 0 ? 0 : -1;
+ if (ret)
+ printf("ret = %d, link = %lx, code = %p, lr = %lx\n",
+ ret, link, code, lr);
}
return ret;
---
Running with this small change, I get:
POST cpu link = 0
ret = -1, link = 0, code = 03fa5ab8, lr = 0
It looks clear to me that link == 0, so the test worked fine.
However, if I take away the "static" from the cpu_post_test_bc()
declaration then everything works fine. Everything also works fine if I
leave the static, but also add the 'noinline' function attribute.
I've posted "objdump -dS" output for post/cpu/b.o with and without
cpu_post_test_bc() declared as static at:
http://www.bork.org/~mort/ppcstatic/
Any hints appreciated. Let me know if any other info is required.
mh
--
Martin Hicks || [EMAIL PROTECTED] || PGP/GnuPG: 0x4C7F2BEE
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