Re: GCC's -fsplit-stack disturbing Mach's vm_allocate

[Svante Signell]

On Fri, 2014-04-18 at 10:03 +0200, Samuel Thibault wrote:
> Samuel Thibault, le Thu 17 Apr 2014 00:03:45 +0200, a écrit :
> > Thomas Schwinge, le Wed 09 Apr 2014 09:36:42 +0200, a écrit :
> > > Well, the first step is to verify that TARGET_THREAD_SPLIT_STACK_OFFSET
> > > and similar configury is correct for the Hurd,
> > 
> > I have added the corresponding field, so we can just use the same offset
> > as on Linux.
> 
> I have uploaded packages on http://people.debian.org/~sthibault/tmp/ so
> Svante can try setting TARGET_THREAD_SPLIT_STACK_OFFSET to 0x30 with
> them.

Status report:
- Without split stack enabled around 70 libgo tests pass and 50 fails,
most of them with a segfault.
- Enabling split stack and using the libc Samuel built all 122 libgo
tests fail with a segfault.
- In both cases simple go programs work, like hello+sqrt.go below.
- The segfault seems to be located at the same code piece according to
gdb (maybe due to exception handling)

cat hello+sqrt.go
package main
import (
        "fmt"
)
func main() {
        fmt.Printf("Hello, world.  Sqrt(2) = %v\n", Sqrt(2))
}

I have not been able to use a local go library function, e.g. package
newmath, and the go frontend is not yet available for GNU/Hurd.

However, it seems that something triggers the segfaults when running
make -C build/i486-gnu/libgo check (both with and w/o split-stack)
while setting the keep parameter in ./src/libgo/testsuite/gotest
and running them manually some of them work?? As a first glance, about
the same number of tests succeeds with and w/o split stack :) Some of
the failing tests still seems random, sometimes they pass, sometimes
they fail.