* config/i386/tm-i386bsd.h (SIGTRAMP_START, SIGTRAMP_END, FRAME_CHAIN,

	FRAMELESS_FUNCTION_INVOCATION, FRAME_SAVED_PC, SIGCONTEXT_PC_OFFSET):
	Define to make backtracing through sigtramp work.
	* config/vax/tm-vax.h (SIGTRAMP_START, SIGTRAMP_END, TARGET_UPAGES,
	FRAME_SAVED_PC, SIGCONTEXT_PC_OFFSET):  Ditto.

1 files changed, 47 insertions, 0 deletions

diff --git a/gdb/config/i386/tm-i386bsd.h b/gdb/config/i386/tm-i386bsd.h
index 6f4dbd9..f75fd93 100644
--- a/gdb/config/i386/tm-i386bsd.h
+++ b/gdb/config/i386/tm-i386bsd.h
@@ -27,3 +27,50 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
 /* BSDI can't handle them either.  */
 #undef NUM_REGS
 #define NUM_REGS 10
+
+/* On 386 bsd, sigtramp is above the user stack and immediately below
+   the user area. Using constants here allows for cross debugging.
+   These are tested for BSDI but should work on 386BSD.  */
+#define SIGTRAMP_START	0xfdbfdfc0
+#define SIGTRAMP_END	0xfdbfe000
+
+/* The following redefines make backtracing through sigtramp work.
+   They manufacture a fake sigtramp frame and obtain the saved pc in sigtramp
+   from the sigcontext structure which is pushed by the kernel on the
+   user stack, along with a pointer to it.  */
+
+/* FRAME_CHAIN takes a frame's nominal address and produces the frame's
+   chain-pointer.
+   In the case of the i386, the frame's nominal address
+   is the address of a 4-byte word containing the calling frame's address.  */
+#undef FRAME_CHAIN
+#define FRAME_CHAIN(thisframe)  \
+  (thisframe->signal_handler_caller \
+   ? thisframe->frame \
+   : (!inside_entry_file ((thisframe)->pc) \
+      ? read_memory_integer ((thisframe)->frame, 4) \
+      : 0))
+
+/* A macro that tells us whether the function invocation represented
+   by FI does not have a frame on the stack associated with it.  If it
+   does not, FRAMELESS is set to 1, else 0.  */
+#undef FRAMELESS_FUNCTION_INVOCATION
+#define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) \
+  do { \
+    if ((FI)->signal_handler_caller) \
+      (FRAMELESS) = 0; \
+    else \
+      (FRAMELESS) = frameless_look_for_prologue(FI); \
+  } while (0)
+
+/* Saved Pc.  Get it from sigcontext if within sigtramp.  */
+
+/* Offset to saved PC in sigcontext, from <sys/signal.h>.  */
+#define SIGCONTEXT_PC_OFFSET 20
+
+#undef FRAME_SAVED_PC(FRAME)
+#define FRAME_SAVED_PC(FRAME) \
+  (((FRAME)->signal_handler_caller \
+    ? sigtramp_saved_pc (FRAME) \
+    : read_memory_integer ((FRAME)->frame + 4, 4)) \
+   )