[gdb/testsuite] Fix gdb.arch/amd64-disp-step-self-call.exp on freebsdHEADmaster

On x86_64-freebsd, with test-case gdb.arch/amd64-disp-step-self-call.exp, I
run into:
...
(gdb) continue
Continuing.

Program received signal SIGBUS, Bus error.
Object-specific hardware error.
0x000000080051492c in alarm () from /lib/libc.so.7
(gdb) FAIL: $exp: continue to breakpoint: test_call
...

The behaviour is not specific to gdb, it can be reproduced by running the
test-case executable:
...
$ ./outputs/gdb.arch/amd64-disp-step-self-call/amd64-disp-step-self-call
Bus error (core dumped)
$
...

The bus error happens when executing this instruction in alarm:
...
0000000000093910 <alarm>:
   ...
   9392c: 0f 29 45 d0                  	movaps	%xmm0, -0x30(%rbp)
...
because $rbp is not 16-byte aligned.

This can be fixed by adding the missing frame setup instructions at the start
of main in amd64-disp-step-self-call.S:
...
 main:
+	pushq	%rbp
+	movq	%rsp, %rbp
...

Instead, fix this by moving main from the assembly file to the c file, which
has the same effect.

Also remove the done label, which looks like a copy-past left-over.  Instead,
add an unreachable function and use it where appropriate.

Do the same for i386 case (which makes the source files identical for the
amd64 and i386 case, but I decided to leave it like that).

Tested on x86_64-freebsd and x86_64-linux.

0 files changed, 0 insertions, 0 deletions