Add a kluge to allow kgdb(1) to inject its own frame sniffer in the

list of frame sniffers so that trapframes can be detected. The kluge
is needed because this version of gdb only supports appending a
sniffer to the list of sniffers and the moment kgdb gets a chance to
add its own frame sniffer, the target's default frame sniffer is
already in the list. Since the default frame sniffer claims any
frame thrown at it, kgdb's frame sniffer never gets to smell (a
process much akin to tasting, but with lesser chance of hurling :-)

This commit adds dummy frame sniffers that never claim a frame and
as such don't fix anything yet. However, we now have frame sniffers
and they are being called, so it's just a matter of adding meat to
the bones and we'll be able to properly unwind across trapframes.

MFC after: 1 week

11 files changed, 188 insertions, 13 deletions

diff --git a/gnu/usr.bin/gdb/kgdb/kgdb.h b/gnu/usr.bin/gdb/kgdb/kgdb.h
index b545ebb..2103acd 100644
--- a/gnu/usr.bin/gdb/kgdb/kgdb.h
+++ b/gnu/usr.bin/gdb/kgdb/kgdb.h
@@ -29,7 +29,7 @@
 #ifndef _KGDB_H_
 #define	_KGDB_H_
 
-struct	thread_info;
+struct thread_info;
 
 extern kvm_t *kvm;
 extern int verbose;
@@ -50,6 +50,8 @@ void kgdb_target(void);
 void kgdb_trgt_fetch_registers(int);
 void kgdb_trgt_store_registers(int);
 
+frame_unwind_sniffer_ftype kgdb_trgt_trapframe_sniffer;
+
 struct kthr *kgdb_thr_first(void);
 struct kthr *kgdb_thr_init(void);
 struct kthr *kgdb_thr_lookup_tid(int);
diff --git a/gnu/usr.bin/gdb/kgdb/kthr.c b/gnu/usr.bin/gdb/kgdb/kthr.c
index 505605d..9156f1a 100644
--- a/gnu/usr.bin/gdb/kgdb/kthr.c
+++ b/gnu/usr.bin/gdb/kgdb/kthr.c
@@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
 #include <stdlib.h>
 
 #include <defs.h>
+#include <frame-unwind.h>
 
 #include "kgdb.h"
 
diff --git a/gnu/usr.bin/gdb/kgdb/main.c b/gnu/usr.bin/gdb/kgdb/main.c
index 856cb93..b07328c 100644
--- a/gnu/usr.bin/gdb/kgdb/main.c
+++ b/gnu/usr.bin/gdb/kgdb/main.c
@@ -50,6 +50,7 @@ __FBSDID("$FreeBSD$");
 /* libgdb stuff. */
 #include <defs.h>
 #include <frame.h>
+#include <frame-unwind.h>
 #include <inferior.h>
 #include <interps.h>
 #include <cli-out.h>
@@ -61,6 +62,8 @@ __FBSDID("$FreeBSD$");
 
 extern void (*init_ui_hook)(char *);
 
+extern frame_unwind_sniffer_ftype *kgdb_sniffer_kluge;
+
 extern void symbol_file_add_main (char *args, int from_tty);
 
 #include "kgdb.h"
@@ -478,5 +481,7 @@ main(int argc, char *argv[])
 
 	init_ui_hook = kgdb_init;
 
+	kgdb_sniffer_kluge = kgdb_trgt_trapframe_sniffer;
+
 	return (gdb_main(&args));
 }
diff --git a/gnu/usr.bin/gdb/kgdb/trgt.c b/gnu/usr.bin/gdb/kgdb/trgt.c
index 87487ce..dac66c4 100644
--- a/gnu/usr.bin/gdb/kgdb/trgt.c
+++ b/gnu/usr.bin/gdb/kgdb/trgt.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 
 #include <defs.h>
 #include <command.h>
+#include <frame-unwind.h>
 #include <gdbthread.h>
 #include <inferior.h>
 #include <regcache.h>
diff --git a/gnu/usr.bin/gdb/kgdb/trgt_alpha.c b/gnu/usr.bin/gdb/kgdb/trgt_alpha.c
index 336970b..c63c005 100644
--- a/gnu/usr.bin/gdb/kgdb/trgt_alpha.c
+++ b/gnu/usr.bin/gdb/kgdb/trgt_alpha.c
@@ -33,13 +33,14 @@ __FBSDID("$FreeBSD$");
 #include <kvm.h>
 #include <string.h>
 
-#include "kgdb.h"
-
 #include <defs.h>
 #include <target.h>
 #include <gdbthread.h>
 #include <inferior.h>
 #include <regcache.h>
+#include <frame-unwind.h>
+
+#include "kgdb.h"
 
 void
 kgdb_trgt_fetch_registers(int regno __unused)
@@ -71,3 +72,29 @@ kgdb_trgt_store_registers(int regno __unused)
 {
 	fprintf_unfiltered(gdb_stderr, "XXX: %s\n", __func__);
 }
+
+static void
+kgdb_trgt_trapframe_this_id(struct frame_info *next_frame, void **this_cache,
+    struct frame_id *this_id)
+{
+}
+
+static void
+kgdb_trgt_trapframe_prev_register(struct frame_info *next_frame,
+    void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp,
+    CORE_ADDR *addrp, int *realnump, void *valuep)
+{
+}
+
+static const struct frame_unwind kgdb_trgt_trapframe_unwind = {
+        UNKNOWN_FRAME,
+        &kgdb_trgt_trapframe_this_id,
+        &kgdb_trgt_trapframe_prev_register
+};
+
+const struct frame_unwind *
+kgdb_trgt_trapframe_sniffer(struct frame_info *next_frame)
+{
+
+        return (NULL);
+}
diff --git a/gnu/usr.bin/gdb/kgdb/trgt_amd64.c b/gnu/usr.bin/gdb/kgdb/trgt_amd64.c
index 0907d0d..bd1558f 100644
--- a/gnu/usr.bin/gdb/kgdb/trgt_amd64.c
+++ b/gnu/usr.bin/gdb/kgdb/trgt_amd64.c
@@ -33,13 +33,14 @@ __FBSDID("$FreeBSD$");
 #include <kvm.h>
 #include <string.h>
 
-#include "kgdb.h"
-
 #include <defs.h>
 #include <target.h>
 #include <gdbthread.h>
 #include <inferior.h>
 #include <regcache.h>
+#include <frame-unwind.h>
+
+#include "kgdb.h"
 
 void
 kgdb_trgt_fetch_registers(int regno __unused)
@@ -71,3 +72,29 @@ kgdb_trgt_store_registers(int regno __unused)
 {
 	fprintf_unfiltered(gdb_stderr, "XXX: %s\n", __func__);
 }
+
+static void
+kgdb_trgt_trapframe_this_id(struct frame_info *next_frame, void **this_cache,
+    struct frame_id *this_id)
+{
+}
+
+static void
+kgdb_trgt_trapframe_prev_register(struct frame_info *next_frame,
+    void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp,
+    CORE_ADDR *addrp, int *realnump, void *valuep)
+{
+}
+
+static const struct frame_unwind kgdb_trgt_trapframe_unwind = {
+        UNKNOWN_FRAME,
+        &kgdb_trgt_trapframe_this_id,
+        &kgdb_trgt_trapframe_prev_register
+};
+
+const struct frame_unwind *
+kgdb_trgt_trapframe_sniffer(struct frame_info *next_frame)
+{
+
+        return (NULL);
+}
diff --git a/gnu/usr.bin/gdb/kgdb/trgt_i386.c b/gnu/usr.bin/gdb/kgdb/trgt_i386.c
index 96dad51..eb58df3 100644
--- a/gnu/usr.bin/gdb/kgdb/trgt_i386.c
+++ b/gnu/usr.bin/gdb/kgdb/trgt_i386.c
@@ -33,13 +33,14 @@ __FBSDID("$FreeBSD$");
 #include <kvm.h>
 #include <string.h>
 
-#include "kgdb.h"
-
 #include <defs.h>
 #include <target.h>
 #include <gdbthread.h>
 #include <inferior.h>
 #include <regcache.h>
+#include <frame-unwind.h>
+
+#include "kgdb.h"
 
 void
 kgdb_trgt_fetch_registers(int regno __unused)
@@ -67,3 +68,29 @@ kgdb_trgt_store_registers(int regno __unused)
 {
 	fprintf_unfiltered(gdb_stderr, "XXX: %s\n", __func__);
 }
+
+static void
+kgdb_trgt_trapframe_this_id(struct frame_info *next_frame, void **this_cache,
+    struct frame_id *this_id)
+{
+}
+
+static void
+kgdb_trgt_trapframe_prev_register(struct frame_info *next_frame,
+    void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp,
+    CORE_ADDR *addrp, int *realnump, void *valuep)
+{
+}
+
+static const struct frame_unwind kgdb_trgt_trapframe_unwind = {
+        UNKNOWN_FRAME,
+        &kgdb_trgt_trapframe_this_id,
+        &kgdb_trgt_trapframe_prev_register
+};
+
+const struct frame_unwind *
+kgdb_trgt_trapframe_sniffer(struct frame_info *next_frame)
+{
+
+        return (NULL);
+}
diff --git a/gnu/usr.bin/gdb/kgdb/trgt_ia64.c b/gnu/usr.bin/gdb/kgdb/trgt_ia64.c
index bfceba4..7d9e119 100644
--- a/gnu/usr.bin/gdb/kgdb/trgt_ia64.c
+++ b/gnu/usr.bin/gdb/kgdb/trgt_ia64.c
@@ -34,13 +34,14 @@ __FBSDID("$FreeBSD$");
 #include <kvm.h>
 #include <string.h>
 
-#include "kgdb.h"
-
 #include <defs.h>
 #include <target.h>
 #include <gdbthread.h>
 #include <inferior.h>
 #include <regcache.h>
+#include <frame-unwind.h>
+
+#include "kgdb.h"
 
 void
 kgdb_trgt_fetch_registers(int regno __unused)
@@ -131,3 +132,29 @@ kgdb_trgt_store_registers(int regno __unused)
 {
 	fprintf_unfiltered(gdb_stderr, "XXX: %s\n", __func__);
 }
+
+static void
+kgdb_trgt_trapframe_this_id(struct frame_info *next_frame, void **this_cache,
+    struct frame_id *this_id)
+{
+}
+
+static void
+kgdb_trgt_trapframe_prev_register(struct frame_info *next_frame,
+    void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp,
+    CORE_ADDR *addrp, int *realnump, void *valuep)
+{
+}
+
+static const struct frame_unwind kgdb_trgt_trapframe_unwind = {
+        UNKNOWN_FRAME,
+        &kgdb_trgt_trapframe_this_id,
+        &kgdb_trgt_trapframe_prev_register
+};
+
+const struct frame_unwind *
+kgdb_trgt_trapframe_sniffer(struct frame_info *next_frame)
+{
+
+        return (NULL);
+}
diff --git a/gnu/usr.bin/gdb/kgdb/trgt_sparc64.c b/gnu/usr.bin/gdb/kgdb/trgt_sparc64.c
index 17d8135..d6dcd65 100644
--- a/gnu/usr.bin/gdb/kgdb/trgt_sparc64.c
+++ b/gnu/usr.bin/gdb/kgdb/trgt_sparc64.c
@@ -34,16 +34,17 @@ __FBSDID("$FreeBSD$");
 #include <kvm.h>
 #include <string.h>
 
-#include "kgdb.h"
-
 #include <defs.h>
 #include <target.h>
 #include <gdbthread.h>
 #include <inferior.h>
 #include <regcache.h>
+#include <frame-unwind.h>
 #include <sparc-tdep.h>
 #include <sparc64-tdep.h>
 
+#include "kgdb.h"
+
 void
 kgdb_trgt_fetch_registers(int regno __unused)
 {
@@ -70,3 +71,29 @@ kgdb_trgt_store_registers(int regno __unused)
 {
 	fprintf_unfiltered(gdb_stderr, "XXX: %s\n", __func__);
 }
+
+static void
+kgdb_trgt_trapframe_this_id(struct frame_info *next_frame, void **this_cache,
+    struct frame_id *this_id)
+{
+}
+
+static void
+kgdb_trgt_trapframe_prev_register(struct frame_info *next_frame,
+    void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp,
+    CORE_ADDR *addrp, int *realnump, void *valuep)
+{
+}
+
+static const struct frame_unwind kgdb_trgt_trapframe_unwind = {
+        UNKNOWN_FRAME,
+        &kgdb_trgt_trapframe_this_id,
+        &kgdb_trgt_trapframe_prev_register
+};
+
+const struct frame_unwind *
+kgdb_trgt_trapframe_sniffer(struct frame_info *next_frame)
+{
+
+        return (NULL);
+}
diff --git a/gnu/usr.bin/gdb/libgdb/Makefile b/gnu/usr.bin/gdb/libgdb/Makefile
index e9e92ca..29598d3 100644
--- a/gnu/usr.bin/gdb/libgdb/Makefile
+++ b/gnu/usr.bin/gdb/libgdb/Makefile
@@ -18,7 +18,7 @@ SRCS=	annotate.c arch-utils.c auxv.c ax-gdb.c ax-general.c \
 	elfread.c environ.c eval.c event-loop.c event-top.c exec.c \
 	expprint.c \
 	f-exp.y f-lang.c f-typeprint.c f-valprint.c findvar.c \
-	${_fork_child} frame-base.c frame-unwind.c frame.c \
+	${_fork_child} frame-base.c frame-unwind-kluge.c frame.c \
 	gdb-events.c gdbarch.c gdbtypes.c gnu-v2-abi.c gnu-v3-abi.c \
 	hpacc-abi.c \
 	inf-loop.c infcall.c infcmd.c inflow.c ${_infptrace} infrun.c \
@@ -59,7 +59,11 @@ _infptrace= infptrace.c
 _inftarg= inftarg.c
 .endif
 
-GENSRCS= version.c
+GENSRCS= frame-unwind-kluge.c version.c
+
+frame-unwind-kluge.c: frame-unwind.diff
+	cat ${CNTRB_GDB}/gdb/frame-unwind.c > ${.TARGET}
+	patch ${.TARGET} ${.ALLSRC}
 
 version.c:
 	echo '#include "version.h"' >  ${.TARGET}
diff --git a/gnu/usr.bin/gdb/libgdb/frame-unwind.diff b/gnu/usr.bin/gdb/libgdb/frame-unwind.diff
new file mode 100644
index 0000000..8143c55
--- /dev/null
+++ b/gnu/usr.bin/gdb/libgdb/frame-unwind.diff
@@ -0,0 +1,27 @@
+$FreeBSD$
+
+Index: frame-unwind.c
+===================================================================
+RCS file: /home/ncvs/src/contrib/gdb/gdb/frame-unwind.c,v
+retrieving revision 1.1.1.1
+diff -u -r1.1.1.1 frame-unwind.c
+--- frame-unwind.c	20 Jun 2004 18:16:58 -0000	1.1.1.1
++++ frame-unwind.c	10 Sep 2005 06:36:55 -0000
+@@ -27,6 +27,8 @@
+ 
+ static struct gdbarch_data *frame_unwind_data;
+ 
++frame_unwind_sniffer_ftype *kgdb_sniffer_kluge;
++
+ struct frame_unwind_table
+ {
+   frame_unwind_sniffer_ftype **sniffer;
+@@ -49,6 +51,8 @@
+ {
+   struct frame_unwind_table *table = XCALLOC (1, struct frame_unwind_table);
+   append_predicate (table, dummy_frame_sniffer);
++  if (kgdb_sniffer_kluge != NULL)
++    append_predicate (table, kgdb_sniffer_kluge);
+   return table;
+ }
+