FreeBSD x86: Use tramp-frame for signal frames.

Use a register map to describe the registers in mcontext_t as part of
the signal frame as is done on several other FreeBSD arches.  This
permits fetching the fsbase and gsbase register values from the signal
frame for both amd64 and i386 and permits fetching additional segment
registers stored as 16-bit values on amd64.

While signal frames on FreeBSD do contain floating point/XSAVE state,
these unwinders do not attempt to supply those registers.  The
existing x86 signal frame uwinders do not support these registers, and
the only existing functions which handle FSAVE/FXSAVE/XSAVE state all
work with regcaches.  In the future these unwinders could create a
tempory regcache, collect floating point registers, and then supply
values out of the regcache into the trad-frame.

1 files changed, 0 insertions, 58 deletions

diff --git a/gdb/amd64-fbsd-nat.c b/gdb/amd64-fbsd-nat.c
index 3c79a40..f9bd45d 100644
--- a/gdb/amd64-fbsd-nat.c
+++ b/gdb/amd64-fbsd-nat.c
@@ -213,8 +213,6 @@ void _initialize_amd64fbsd_nat ();
 void
 _initialize_amd64fbsd_nat ()
 {
-  int offset;
-
   amd64_native_gregset32_reg_offset = amd64fbsd32_r_reg_offset;
   amd64_native_gregset64_reg_offset = amd64fbsd64_r_reg_offset;
 
@@ -222,60 +220,4 @@ _initialize_amd64fbsd_nat ()
 
   /* Support debugging kernel virtual memory images.  */
   bsd_kvm_add_target (amd64fbsd_supply_pcb);
-
-  /* To support the recognition of signal handlers, i386-bsd-tdep.c
-     hardcodes some constants.  Inclusion of this file means that we
-     are compiling a native debugger, which means that we can use the
-     system header files and sysctl(3) to get at the relevant
-     information.  */
-
-#define SC_REG_OFFSET amd64fbsd_sc_reg_offset
-
-  /* We only check the program counter, stack pointer and frame
-     pointer since these members of `struct sigcontext' are essential
-     for providing backtraces.  */
-
-#define SC_RIP_OFFSET SC_REG_OFFSET[AMD64_RIP_REGNUM]
-#define SC_RSP_OFFSET SC_REG_OFFSET[AMD64_RSP_REGNUM]
-#define SC_RBP_OFFSET SC_REG_OFFSET[AMD64_RBP_REGNUM]
-
-  /* Override the default value for the offset of the program counter
-     in the sigcontext structure.  */
-  offset = offsetof (struct sigcontext, sc_rip);
-
-  if (SC_RIP_OFFSET != offset)
-    {
-      warning (_("\
-offsetof (struct sigcontext, sc_rip) yields %d instead of %d.\n\
-Please report this to <bug-gdb@gnu.org>."),
-	       offset, SC_RIP_OFFSET);
-    }
-
-  SC_RIP_OFFSET = offset;
-
-  /* Likewise for the stack pointer.  */
-  offset = offsetof (struct sigcontext, sc_rsp);
-
-  if (SC_RSP_OFFSET != offset)
-    {
-      warning (_("\
-offsetof (struct sigcontext, sc_rsp) yields %d instead of %d.\n\
-Please report this to <bug-gdb@gnu.org>."),
-	       offset, SC_RSP_OFFSET);
-    }
-
-  SC_RSP_OFFSET = offset;
-
-  /* And the frame pointer.  */
-  offset = offsetof (struct sigcontext, sc_rbp);
-
-  if (SC_RBP_OFFSET != offset)
-    {
-      warning (_("\
-offsetof (struct sigcontext, sc_rbp) yields %d instead of %d.\n\
-Please report this to <bug-gdb@gnu.org>."),
-	       offset, SC_RBP_OFFSET);
-    }
-
-  SC_RBP_OFFSET = offset;
 }