x32: gdbserver's agent bytecode JIT: fix "call" emission

Running fast tracepoint tests on x32 exposes a latent bug in the agent
bytecode jitting.  There's a code path that forgets to emit the call
opcode...  Whoops.  Fixes a bunch of gdb.trace/trace-condition.exp
FAILs, like:

  (gdb)
  continue
  Continuing.

  Thread 1 "trace-condition" received signal SIGSEGV, Segmentation fault.
  0x7ffec016 in ?? ()
  (gdb) FAIL: gdb.trace/trace-condition.exp: ftrace: $rip == *set_point: advance through tracing

gdb/gdbserver/ChangeLog:
2016-08-19  Pedro Alves  <palves@redhat.com>

	* linux-x86-low.c (amd64_emit_call): Emit missing call opcode.

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index f59d389..c28c2cb 100644 (file)
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,9 @@
 2016-08-19  Pedro Alves  <palves@redhat.com>
 
+       * linux-x86-low.c (amd64_emit_call): Emit missing call opcode.
+
+2016-08-19  Pedro Alves  <palves@redhat.com>
+
        * linux-x86-low.c (amd64_install_fast_tracepoint_jump_pad): Fix
        comment.  Use memcpy instead of casting through unsigned long.
 

diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
index 1ba98ba..d847b93 100644 (file)
--- a/gdb/gdbserver/linux-x86-low.c
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -1842,6 +1842,8 @@ amd64_emit_call (CORE_ADDR fn)
   else
     {
       int offset32 = offset64; /* we know we can't overflow here.  */
+
+      buf[i++] = 0xe8; /* call <reladdr> */
       memcpy (buf + i, &offset32, 4);
       i += 4;
     }