Re: CVS commit: src/gnu

[Matt Thomas <matt%3am-software.com@localhost>]

On Feb 24, 2011, at 5:15 PM, riz%netbsd.org@localhost wrote:

> On Thu, Feb 10, 2011 at 07:18:30AM +0000, Matt Thomas wrote:
>> Module Name: src
>> Committed By:        matt
>> Date:                Thu Feb 10 07:18:29 UTC 2011
>> 
>> Modified Files:
>>      src/gnu/dist/gcc4/gcc: config.gcc
>>      src/gnu/dist/gcc4/gcc/config/rs6000: netbsd.h
>>      src/gnu/usr.bin/gcc4/arch/powerpc: tm.h
>> 
>> Log Message:
>> Default NetBSD to -msecure-plt now.
>> 
>> 
>> To generate a diff of this commit:
>> cvs rdiff -u -r1.21 -r1.22 src/gnu/dist/gcc4/gcc/config.gcc
>> cvs rdiff -u -r1.4 -r1.5 src/gnu/dist/gcc4/gcc/config/rs6000/netbsd.h
>> cvs rdiff -u -r1.4 -r1.5 src/gnu/usr.bin/gcc4/arch/powerpc/tm.h
>> 
>> Please note that diffs are not public domain; they are subject to the
>> copyright notices on the relevant files.
>> 
> 
> I just identified this change as the one that's preventing the building of
> shared libs which work on my macppc.  The problem was identified by pooka
> while troubleshooting some rump stuff on one of my systems;  on a system
> built with this change, one of the tests in /usr/tests/toolchain/cc fails.
> When the system is built without -msecure-plt the default, it succeeds.
> 
> The test creates two src files, building one as a shared lib:
> 
> cat > test.c << EOF
> #include <stdlib.h>
> int main(void) {callpic();exit(0);}
> EOF
>        cat > pic.c << EOF
> #include <stdio.h>
> int callpic(void) {printf("hello world\n");}
> EOF
> 
> Then:
>            cc -fPIC -dPIC -shared -o libtest.so pic.c
>            cc -o hello test.c -L. -ltest
> 
> env LD_LIBRARY_PATH=. ./hello
> 
> ...which segfaults if the toolchain was built with -msecure-plt.
> 
> Thoughts?

This is a build issue but I don't know how to fix that.  So I checked
in a workaround in rs6000/netbsd.h which causes the right thing to
happen.

When the "native" compiler is built, the host programs aren't getting
all right config defines set up right.  This causes all the patterns
for TARGET_SECURE_PLT to get dropped and so the compiler was emitting
bad code.