gdb: add names to unwinders, add debug messages when looking for unwinder

I wrote this while debugging a problem where the expected unwinder for a
frame wasn't used.  It adds messages to show which unwinders are
considered for a frame, why they are not selected (if an exception is
thrown), and finally which unwinder is selected in the end.

To be able to show a meaningful, human-readable name for the unwinders,
add a "name" field to struct frame_unwind, and update all instances to
include a name.

Here's an example of the output:

    [frame] frame_unwind_find_by_frame: this_frame=0
    [frame] frame_unwind_try_unwinder: trying unwinder "dummy"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "dwarf2 tailcall"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "inline"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "jit"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "python"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "amd64 epilogue"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "i386 epilogue"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "dwarf2"
    [frame] frame_unwind_try_unwinder: yes

gdb/ChangeLog:

	* frame-unwind.h (struct frame_unwind) <name>: New.  Update
	instances everywhere to include this field.
	* frame-unwind.c (frame_unwind_try_unwinder,
	frame_unwind_find_by_frame): Add debug messages.

Change-Id: I813f17777422425f0d08b22499817b23922e8ddb

gdb/ChangeLog

@@ -1,3 +1,10 @@
+2021-06-29  Simon Marchi  <simon.marchi@polymtl.ca>
+
+	* frame-unwind.h (struct frame_unwind) <name>: New.  Update
+	instances everywhere to include this field.
+	* frame-unwind.c (frame_unwind_try_unwinder,
+	frame_unwind_find_by_frame): Add debug messages.
+
 2021-06-29  Simon Marchi  <simon.marchi@polymtl.ca>
 
 	* frame.h (frame_debug_printf): New.

gdb/aarch64-tdep.c

@@ -1116,6 +1116,7 @@ aarch64_prologue_prev_register (struct frame_info *this_frame,
 /* AArch64 prologue unwinder.  */
 static frame_unwind aarch64_prologue_unwind =
 {
+  "aarch64 prologue",
   NORMAL_FRAME,
   aarch64_prologue_frame_unwind_stop_reason,
   aarch64_prologue_this_id,
@@ -1210,6 +1211,7 @@ aarch64_stub_unwind_sniffer (const struct frame_unwind *self,
 /* AArch64 stub unwinder.  */
 static frame_unwind aarch64_stub_unwind =
 {
+  "aarch64 stub",
   NORMAL_FRAME,
   aarch64_stub_frame_unwind_stop_reason,
   aarch64_stub_this_id,

gdb/alpha-mdebug-tdep.c

@@ -333,7 +333,9 @@ alpha_mdebug_frame_sniffer (const struct frame_unwind *self,
   return 1;
 }
 
-static const struct frame_unwind alpha_mdebug_frame_unwind = {
+static const struct frame_unwind alpha_mdebug_frame_unwind =
+{
+  "alpha mdebug",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   alpha_mdebug_frame_this_id,

gdb/alpha-tdep.c

@@ -1012,7 +1012,9 @@ alpha_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind alpha_sigtramp_frame_unwind = {
+static const struct frame_unwind alpha_sigtramp_frame_unwind =
+{
+  "alpha sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   alpha_sigtramp_frame_this_id,
@@ -1429,7 +1431,9 @@ alpha_heuristic_frame_prev_register (struct frame_info *this_frame,
   return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
 }
 
-static const struct frame_unwind alpha_heuristic_frame_unwind = {
+static const struct frame_unwind alpha_heuristic_frame_unwind =
+{
+  "alpha prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   alpha_heuristic_frame_this_id,

gdb/amd64-obsd-tdep.c

@@ -402,10 +402,12 @@ amd64obsd_trapframe_sniffer (const struct frame_unwind *self,
 		   || (startswith (name, "Xintr"))));
 }
 
-static const struct frame_unwind amd64obsd_trapframe_unwind = {
+static const struct frame_unwind amd64obsd_trapframe_unwind =
+{
   /* FIXME: kettenis/20051219: This really is more like an interrupt
      frame, but SIGTRAMP_FRAME would print <signal handler called>,
      which really is not what we want here.  */
+  "amd64 openbsd trap",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   amd64obsd_trapframe_this_id,

gdb/amd64-tdep.c

@@ -2702,6 +2702,7 @@ amd64_frame_prev_register (struct frame_info *this_frame, void **this_cache,
 
 static const struct frame_unwind amd64_frame_unwind =
 {
+  "amd64 prologue",
   NORMAL_FRAME,
   amd64_frame_unwind_stop_reason,
   amd64_frame_this_id,
@@ -2846,6 +2847,7 @@ amd64_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind amd64_sigtramp_frame_unwind =
 {
+  "amd64 sigtramp",
   SIGTRAMP_FRAME,
   amd64_sigtramp_frame_unwind_stop_reason,
   amd64_sigtramp_frame_this_id,
@@ -2981,6 +2983,7 @@ amd64_epilogue_frame_this_id (struct frame_info *this_frame,
 
 static const struct frame_unwind amd64_epilogue_frame_unwind =
 {
+  "amd64 epilogue",
   NORMAL_FRAME,
   amd64_epilogue_frame_unwind_stop_reason,
   amd64_epilogue_frame_this_id,

gdb/amd64-windows-tdep.c

@@ -1178,6 +1178,7 @@ amd64_windows_frame_this_id (struct frame_info *this_frame, void **this_cache,
 
 static const struct frame_unwind amd64_windows_frame_unwind =
 {
+  "amd64 windows",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   &amd64_windows_frame_this_id,

gdb/arc-tdep.c

@@ -1922,6 +1922,7 @@ arc_sigtramp_frame_sniffer (const struct frame_unwind *self,
    accepts the frame.  */
 
 static const struct frame_unwind arc_frame_unwind = {
+  "arc prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   arc_frame_this_id,
@@ -1937,6 +1938,7 @@ static const struct frame_unwind arc_frame_unwind = {
    context.  */
 
 static const struct frame_unwind arc_sigtramp_frame_unwind = {
+  "arc sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   arc_sigtramp_frame_this_id,

gdb/arm-tdep.c

@@ -2027,6 +2027,7 @@ arm_prologue_prev_register (struct frame_info *this_frame,
 }
 
 static frame_unwind arm_prologue_unwind = {
+  "arm prologue",
   NORMAL_FRAME,
   arm_prologue_unwind_stop_reason,
   arm_prologue_this_id,
@@ -2736,6 +2737,7 @@ arm_exidx_unwind_sniffer (const struct frame_unwind *self,
 }
 
 struct frame_unwind arm_exidx_unwind = {
+  "arm exidx",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   arm_prologue_this_id,
@@ -2839,6 +2841,7 @@ arm_epilogue_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind arm_epilogue_frame_unwind =
 {
+  "arm epilogue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   arm_epilogue_frame_this_id,
@@ -2960,6 +2963,7 @@ arm_stub_unwind_sniffer (const struct frame_unwind *self,
 }
 
 struct frame_unwind arm_stub_unwind = {
+  "arm stub",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   arm_stub_this_id,
@@ -3171,6 +3175,7 @@ arm_m_exception_unwind_sniffer (const struct frame_unwind *self,
 
 struct frame_unwind arm_m_exception_unwind =
 {
+  "arm m exception",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   arm_m_exception_this_id,

gdb/avr-tdep.c

@@ -1154,6 +1154,7 @@ avr_frame_prev_register (struct frame_info *this_frame,
 }
 
 static const struct frame_unwind avr_frame_unwind = {
+  "avr prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   avr_frame_this_id,

gdb/bfin-tdep.c

@@ -374,6 +374,7 @@ bfin_frame_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind bfin_frame_unwind =
 {
+  "bfin prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   bfin_frame_this_id,

gdb/bpf-tdep.c

@@ -184,6 +184,7 @@ bpf_frame_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind bpf_frame_unwind =
 {
+  "bpf prologue",
   NORMAL_FRAME,
   bpf_frame_unwind_stop_reason,
   bpf_frame_this_id,

gdb/cris-tdep.c

@@ -437,6 +437,7 @@ cris_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind cris_sigtramp_frame_unwind =
 {
+  "cris sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   cris_sigtramp_frame_this_id,
@@ -900,6 +901,7 @@ cris_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 
 static const struct frame_unwind cris_frame_unwind = 
 {
+  "cris prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   cris_frame_this_id,

gdb/csky-tdep.c

@@ -1916,6 +1916,7 @@ csky_frame_prev_register (struct frame_info *this_frame,
    unwinder.  */
 
 static const struct frame_unwind csky_unwind_cache = {
+  "cski prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   csky_frame_this_id,
@@ -1999,6 +2000,7 @@ csky_stub_prev_register (struct frame_info *this_frame,
 }
 
 static frame_unwind csky_stub_unwind = {
+  "csky stub",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   csky_stub_this_id,

gdb/dummy-frame.c

@@ -378,6 +378,7 @@ dummy_frame_this_id (struct frame_info *this_frame,
 
 const struct frame_unwind dummy_frame_unwind =
 {
+  "dummy",
   DUMMY_FRAME,
   default_frame_unwind_stop_reason,
   dummy_frame_this_id,

gdb/dwarf2/frame-tailcall.c

@@ -468,6 +468,7 @@ tailcall_frame_prev_arch (struct frame_info *this_frame,
 
 const struct frame_unwind dwarf2_tailcall_frame_unwind =
 {
+  "dwarf2 tailcall",
   TAILCALL_FRAME,
   default_frame_unwind_stop_reason,
   tailcall_frame_this_id,

gdb/dwarf2/frame.c

@@ -1380,6 +1380,7 @@ dwarf2_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind dwarf2_frame_unwind =
 {
+  "dwarf2",
   NORMAL_FRAME,
   dwarf2_frame_unwind_stop_reason,
   dwarf2_frame_this_id,
@@ -1391,6 +1392,7 @@ static const struct frame_unwind dwarf2_frame_unwind =
 
 static const struct frame_unwind dwarf2_signal_frame_unwind =
 {
+  "dwarf2 signal",
   SIGTRAMP_FRAME,
   dwarf2_frame_unwind_stop_reason,
   dwarf2_frame_this_id,

gdb/frame-unwind.c

@@ -127,10 +127,13 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache,
 
   try
     {
+      frame_debug_printf ("trying unwinder \"%s\"", unwinder->name);
       res = unwinder->sniffer (unwinder, this_frame, this_cache);
     }
   catch (const gdb_exception &ex)
     {
+      frame_debug_printf ("caught exception: %s", ex.message->c_str ());
+
       /* Catch all exceptions, caused by either interrupt or error.
 	 Reset *THIS_CACHE, unless something reinitialized the frame
 	 cache meanwhile, in which case THIS_FRAME/THIS_CACHE are now
@@ -153,9 +156,13 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache,
     }
 
   if (res)
-    return 1;
+    {
+      frame_debug_printf ("yes");
+      return 1;
+    }
   else
     {
+      frame_debug_printf ("no");
       /* Don't set *THIS_CACHE to NULL here, because sniffer has to do
 	 so.  */
       frame_cleanup_after_sniffer (this_frame);
@@ -171,6 +178,8 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache,
 void
 frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache)
 {
+  frame_debug_printf ("this_frame=%d", frame_relative_level (this_frame));
+
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
   struct frame_unwind_table *table
     = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data);

gdb/frame-unwind.h

@@ -158,6 +158,7 @@ typedef struct gdbarch *(frame_prev_arch_ftype) (struct frame_info *this_frame,
 
 struct frame_unwind
 {
+  const char *name;
   /* The frame's type.  Should this instead be a collection of
      predicates that test the frame for various attributes?  */
   enum frame_type type;

gdb/frv-linux-tdep.c

@@ -334,6 +334,7 @@ frv_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind frv_linux_sigtramp_frame_unwind =
 {
+  "frv linux sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   frv_linux_sigtramp_frame_this_id,

gdb/frv-tdep.c

@@ -1411,6 +1411,7 @@ frv_frame_prev_register (struct frame_info *this_frame,
 }
 
 static const struct frame_unwind frv_frame_unwind = {
+  "frv prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   frv_frame_this_id,

gdb/ft32-tdep.c

@@ -525,6 +525,7 @@ ft32_frame_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind ft32_frame_unwind =
 {
+  "ft32 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   ft32_frame_this_id,

gdb/h8300-tdep.c

@@ -501,6 +501,7 @@ h8300_frame_prev_register (struct frame_info *this_frame, void **this_cache,
 }
 
 static const struct frame_unwind h8300_frame_unwind = {
+  "h8300 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   h8300_frame_this_id,

gdb/hppa-linux-tdep.c

@@ -309,6 +309,7 @@ hppa_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
 }
 
 static const struct frame_unwind hppa_linux_sigtramp_frame_unwind = {
+  "hppa linux sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   hppa_linux_sigtramp_frame_this_id,

gdb/hppa-tdep.c

@@ -2302,6 +2302,7 @@ hppa_frame_unwind_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind hppa_frame_unwind =
 {
+  "hppa unwind table",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   hppa_frame_this_id,
@@ -2414,6 +2415,7 @@ hppa_fallback_frame_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind hppa_fallback_frame_unwind =
 {
+  "hppa prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   hppa_fallback_frame_this_id,
@@ -2494,6 +2496,7 @@ hppa_stub_unwind_sniffer (const struct frame_unwind *self,
 }
 
 static const struct frame_unwind hppa_stub_frame_unwind = {
+  "hppa stub",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   hppa_stub_frame_this_id,

gdb/i386-obsd-tdep.c

@@ -391,6 +391,7 @@ i386obsd_trapframe_sniffer (const struct frame_unwind *self,
 }
 
 static const struct frame_unwind i386obsd_trapframe_unwind = {
+  "i386 openbsd trap",
   /* FIXME: kettenis/20051219: This really is more like an interrupt
      frame, but SIGTRAMP_FRAME would print <signal handler called>,
      which really is not what we want here.  */

gdb/i386-tdep.c

@@ -2196,6 +2196,7 @@ i386_frame_prev_register (struct frame_info *this_frame, void **this_cache,
 
 static const struct frame_unwind i386_frame_unwind =
 {
+  "i386 prologue",
   NORMAL_FRAME,
   i386_frame_unwind_stop_reason,
   i386_frame_this_id,
@@ -2317,6 +2318,7 @@ i386_epilogue_frame_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind i386_epilogue_frame_unwind =
 {
+  "i386 epilogue",
   NORMAL_FRAME,
   i386_epilogue_frame_unwind_stop_reason,
   i386_epilogue_frame_this_id,
@@ -2398,6 +2400,7 @@ i386_stack_tramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind i386_stack_tramp_frame_unwind =
 {
+  "i386 stack tramp",
   NORMAL_FRAME,
   i386_epilogue_frame_unwind_stop_reason,
   i386_epilogue_frame_this_id,
@@ -2545,6 +2548,7 @@ i386_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind i386_sigtramp_frame_unwind =
 {
+  "i386 sigtramp",
   SIGTRAMP_FRAME,
   i386_sigtramp_frame_unwind_stop_reason,
   i386_sigtramp_frame_this_id,

gdb/ia64-tdep.c

@@ -2161,6 +2161,7 @@ ia64_frame_prev_register (struct frame_info *this_frame, void **this_cache,
  
 static const struct frame_unwind ia64_frame_unwind =
 {
+  "ia64 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   &ia64_frame_this_id,
@@ -2348,6 +2349,7 @@ ia64_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind ia64_sigtramp_frame_unwind =
 {
+  "ia64 sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   ia64_sigtramp_frame_this_id,
@@ -3006,6 +3008,7 @@ ia64_libunwind_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind ia64_libunwind_frame_unwind =
 {
+  "ia64 libunwind",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   ia64_libunwind_frame_this_id,
@@ -3094,6 +3097,7 @@ ia64_libunwind_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind ia64_libunwind_sigtramp_frame_unwind =
 {
+  "ia64 libunwind sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   ia64_libunwind_sigtramp_frame_this_id,

gdb/inline-frame.c

@@ -263,6 +263,7 @@ inline_frame_sniffer (const struct frame_unwind *self,
 }
 
 const struct frame_unwind inline_frame_unwind = {
+  "inline",
   INLINE_FRAME,
   default_frame_unwind_stop_reason,
   inline_frame_this_id,

gdb/iq2000-tdep.c

@@ -426,6 +426,7 @@ iq2000_frame_this_id (struct frame_info *this_frame, void **this_cache,
 }
 
 static const struct frame_unwind iq2000_frame_unwind = {
+  "iq2000 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   iq2000_frame_this_id,

gdb/jit.c

@@ -1048,6 +1048,7 @@ jit_frame_prev_register (struct frame_info *this_frame, void **cache, int reg)
 
 static const struct frame_unwind jit_frame_unwind =
 {
+  "jit",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   jit_frame_this_id,

gdb/lm32-tdep.c

@@ -455,6 +455,7 @@ lm32_frame_prev_register (struct frame_info *this_frame,
 }
 
 static const struct frame_unwind lm32_frame_unwind = {
+  "lm32 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   lm32_frame_this_id,

gdb/m32c-tdep.c

@@ -1935,6 +1935,7 @@ m32c_prev_register (struct frame_info *this_frame,
 
 
 static const struct frame_unwind m32c_unwind = {
+  "m32c prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   m32c_this_id,

gdb/m32r-linux-tdep.c

@@ -302,6 +302,7 @@ m32r_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
 }
 
 static const struct frame_unwind m32r_linux_sigtramp_frame_unwind = {
+  "m32r linux sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   m32r_linux_sigtramp_frame_this_id,

gdb/m32r-tdep.c

@@ -835,6 +835,7 @@ m32r_frame_prev_register (struct frame_info *this_frame,
 }
 
 static const struct frame_unwind m32r_frame_unwind = {
+  "m32r prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   m32r_frame_this_id,

gdb/m68hc11-tdep.c

@@ -924,6 +924,7 @@ m68hc11_frame_prev_register (struct frame_info *this_frame,
 }
 
 static const struct frame_unwind m68hc11_frame_unwind = {
+  "m68hc11 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   m68hc11_frame_this_id,

gdb/m68k-linux-tdep.c

@@ -316,6 +316,7 @@ m68k_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind m68k_linux_sigtramp_frame_unwind =
 {
+  "m68k linux sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   m68k_linux_sigtramp_frame_this_id,

gdb/m68k-tdep.c

@@ -1003,6 +1003,7 @@ m68k_frame_prev_register (struct frame_info *this_frame, void **this_cache,
 
 static const struct frame_unwind m68k_frame_unwind =
 {
+  "m68k prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   m68k_frame_this_id,

gdb/mep-tdep.c

@@ -2053,6 +2053,7 @@ mep_frame_prev_register (struct frame_info *this_frame,
 
 
 static const struct frame_unwind mep_frame_unwind = {
+  "mep prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   mep_frame_this_id,

gdb/microblaze-tdep.c

@@ -492,6 +492,7 @@ microblaze_frame_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind microblaze_frame_unwind =
 {
+  "microblaze prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   microblaze_frame_this_id,

gdb/mips-sde-tdep.c

@@ -164,6 +164,7 @@ mips_sde_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind mips_sde_frame_unwind =
 {
+  "mips sde sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   mips_sde_frame_this_id,

gdb/mips-tdep.c

@@ -2901,6 +2901,7 @@ mips_insn16_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind mips_insn16_frame_unwind =
 {
+  "mips insn16 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   mips_insn16_frame_this_id,
@@ -3336,6 +3337,7 @@ mips_micro_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind mips_micro_frame_unwind =
 {
+  "mips micro prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   mips_micro_frame_this_id,
@@ -3711,6 +3713,7 @@ mips_insn32_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind mips_insn32_frame_unwind =
 {
+  "mips insn32 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   mips_insn32_frame_this_id,
@@ -3827,6 +3830,7 @@ mips_stub_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind mips_stub_frame_unwind =
 {
+  "mips stub",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   mips_stub_frame_this_id,

gdb/mn10300-tdep.c

@@ -1132,6 +1132,7 @@ mn10300_frame_prev_register (struct frame_info *this_frame,
 }
 
 static const struct frame_unwind mn10300_frame_unwind = {
+  "mn10300 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   mn10300_frame_this_id, 

gdb/moxie-tdep.c

@@ -587,6 +587,7 @@ moxie_frame_prev_register (struct frame_info *this_frame,
 }
 
 static const struct frame_unwind moxie_frame_unwind = {
+  "moxie prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   moxie_frame_this_id,

gdb/msp430-tdep.c

@@ -538,6 +538,7 @@ msp430_prev_register (struct frame_info *this_frame,
 }
 
 static const struct frame_unwind msp430_unwind = {
+  "msp430 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   msp430_this_id,

gdb/nds32-tdep.c

@@ -997,6 +997,7 @@ nds32_frame_prev_register (struct frame_info *this_frame, void **this_cache,
 
 static const struct frame_unwind nds32_frame_unwind =
 {
+  "nds32 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   nds32_frame_this_id,
@@ -1380,6 +1381,7 @@ nds32_epilogue_frame_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind nds32_epilogue_frame_unwind =
 {
+  "nds32 epilogue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   nds32_epilogue_frame_this_id,

gdb/nios2-tdep.c

@@ -1979,6 +1979,7 @@ nios2_frame_base_address (struct frame_info *this_frame, void **this_cache)
 
 static const struct frame_unwind nios2_frame_unwind =
 {
+  "nios2 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   nios2_frame_this_id,
@@ -2079,6 +2080,7 @@ nios2_stub_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind nios2_stub_frame_unwind =
 {
+  "nios2 stub",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   nios2_stub_frame_this_id,

gdb/or1k-tdep.c

@@ -1096,6 +1096,7 @@ or1k_frame_prev_register (struct frame_info *this_frame,
 /* Data structures for the normal prologue-analysis-based unwinder.  */
 
 static const struct frame_unwind or1k_frame_unwind = {
+  "or1k prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   or1k_frame_this_id,

gdb/ppc-fbsd-tdep.c

@@ -263,6 +263,7 @@ ppcfbsd_sigtramp_frame_prev_register (struct frame_info *this_frame,
 }
 
 static const struct frame_unwind ppcfbsd_sigtramp_frame_unwind = {
+  "ppc freebsd sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   ppcfbsd_sigtramp_frame_this_id,

gdb/ppc-obsd-tdep.c

@@ -232,6 +232,7 @@ ppcobsd_sigtramp_frame_prev_register (struct frame_info *this_frame,
 }
 
 static const struct frame_unwind ppcobsd_sigtramp_frame_unwind = {
+  "ppc openbsd sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   ppcobsd_sigtramp_frame_this_id,

gdb/python/py-unwind.c

@@ -680,6 +680,7 @@ pyuw_on_new_gdbarch (struct gdbarch *newarch)
       struct frame_unwind *unwinder
 	  = GDBARCH_OBSTACK_ZALLOC (newarch, struct frame_unwind);
 
+      unwinder->name = "python";
       unwinder->type = NORMAL_FRAME;
       unwinder->stop_reason = default_frame_unwind_stop_reason;
       unwinder->this_id = pyuw_this_id;

gdb/record-btrace.c

@@ -1889,6 +1889,7 @@ record_btrace_frame_dealloc_cache (struct frame_info *self, void *this_cache)
 
 const struct frame_unwind record_btrace_frame_unwind =
 {
+  "record-btrace",
   NORMAL_FRAME,
   record_btrace_frame_unwind_stop_reason,
   record_btrace_frame_this_id,
@@ -1900,6 +1901,7 @@ const struct frame_unwind record_btrace_frame_unwind =
 
 const struct frame_unwind record_btrace_tailcall_frame_unwind =
 {
+  "record-btrace tailcall",
   TAILCALL_FRAME,
   record_btrace_frame_unwind_stop_reason,
   record_btrace_frame_this_id,

gdb/riscv-tdep.c

@@ -3320,6 +3320,7 @@ riscv_frame_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind riscv_frame_unwind =
 {
+  /*.name          =*/ "riscv prologue",
   /*.type          =*/ NORMAL_FRAME,
   /*.stop_reason   =*/ default_frame_unwind_stop_reason,
   /*.this_id       =*/ riscv_frame_this_id,

gdb/rl78-tdep.c

@@ -1183,6 +1183,7 @@ rl78_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind rl78_unwind =
 {
+  "rl78 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   rl78_this_id,

gdb/rs6000-aix-tdep.c

@@ -156,6 +156,7 @@ aix_sighandle_frame_sniffer (const struct frame_unwind *self,
 /* AIX signal handler frame unwinder */
 
 static const struct frame_unwind aix_sighandle_frame_unwind = {
+  "rs6000 aix sighandle",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   aix_sighandle_frame_this_id,

gdb/rs6000-tdep.c

@@ -3783,6 +3783,7 @@ rs6000_frame_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind rs6000_frame_unwind =
 {
+  "rs6000 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   rs6000_frame_this_id,
@@ -3882,6 +3883,7 @@ rs6000_epilogue_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind rs6000_epilogue_frame_unwind =
 {
+  "rs6000 epilogue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   rs6000_epilogue_frame_this_id, rs6000_epilogue_frame_prev_register,

gdb/rx-tdep.c

@@ -630,6 +630,7 @@ rx_exception_sniffer (const struct frame_unwind *self,
    analyzer.  */
 
 static const struct frame_unwind rx_frame_unwind = {
+  "rx prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   rx_frame_this_id,
@@ -642,6 +643,7 @@ static const struct frame_unwind rx_frame_unwind = {
    analyzer.  */
 
 static const struct frame_unwind rx_exception_unwind = {
+  "rx exception",
   /* SIGTRAMP_FRAME could be used here, but backtraces are less informative.  */
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,

gdb/s12z-tdep.c

@@ -467,6 +467,7 @@ s12z_frame_prev_register (struct frame_info *this_frame,
 
 /* Data structures for the normal prologue-analysis-based unwinder.  */
 static const struct frame_unwind s12z_frame_unwind = {
+  "s12z prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   s12z_frame_this_id,

gdb/s390-linux-tdep.c

@@ -542,6 +542,7 @@ s390_sigtramp_frame_sniffer (const struct frame_unwind *self,
 /* S390 sigtramp frame unwinder.  */
 
 static const struct frame_unwind s390_sigtramp_frame_unwind = {
+  "s390 linux sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   s390_sigtramp_frame_this_id,

gdb/s390-tdep.c

@@ -2634,6 +2634,7 @@ s390_frame_prev_register (struct frame_info *this_frame,
 /* Default S390 frame unwinder.  */
 
 static const struct frame_unwind s390_frame_unwind = {
+  "s390 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   s390_frame_this_id,
@@ -2727,6 +2728,7 @@ s390_stub_frame_sniffer (const struct frame_unwind *self,
 /* S390 stub frame unwinder.  */
 
 static const struct frame_unwind s390_stub_frame_unwind = {
+  "s390 stub",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   s390_stub_frame_this_id,

gdb/score-tdep.c

@@ -1351,6 +1351,7 @@ score_prologue_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind score_prologue_unwind =
 {
+  "score prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   score_prologue_this_id,

gdb/sentinel-frame.c

@@ -79,6 +79,7 @@ sentinel_frame_prev_arch (struct frame_info *this_frame,
 
 const struct frame_unwind sentinel_frame_unwind =
 {
+  "sentinel",
   SENTINEL_FRAME,
   default_frame_unwind_stop_reason,
   sentinel_frame_this_id,

gdb/sh-tdep.c

@@ -1968,6 +1968,7 @@ sh_frame_this_id (struct frame_info *this_frame, void **this_cache,
 }
 
 static const struct frame_unwind sh_frame_unwind = {
+  "sh prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   sh_frame_this_id,
@@ -2034,6 +2035,7 @@ sh_stub_unwind_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind sh_stub_unwind =
 {
+  "sh stub",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   sh_stub_this_id,

gdb/sparc-netbsd-tdep.c

@@ -251,6 +251,7 @@ sparc32nbsd_sigcontext_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind sparc32nbsd_sigcontext_frame_unwind =
 {
+  "sparc32 netbsd sigcontext",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   sparc32nbsd_sigcontext_frame_this_id,

gdb/sparc-obsd-tdep.c

@@ -136,6 +136,7 @@ sparc32obsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
 }
 static const struct frame_unwind sparc32obsd_sigtramp_frame_unwind =
 {
+  "sparc32 openbsd sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   sparc32obsd_sigtramp_frame_this_id,

gdb/sparc-sol2-tdep.c

@@ -182,6 +182,7 @@ sparc32_sol2_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind sparc32_sol2_sigtramp_frame_unwind =
 {
+  "sparc32 solaris sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   sparc32_sol2_sigtramp_frame_this_id,

gdb/sparc-tdep.c

@@ -1358,6 +1358,7 @@ sparc32_frame_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind sparc32_frame_unwind =
 {
+  "sparc32 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   sparc32_frame_this_id,

gdb/sparc64-fbsd-tdep.c

@@ -199,6 +199,7 @@ sparc64fbsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind sparc64fbsd_sigtramp_frame_unwind =
 {
+  "sparc64 freebsd sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   sparc64fbsd_sigtramp_frame_this_id,

gdb/sparc64-netbsd-tdep.c

@@ -225,6 +225,7 @@ sparc64nbsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind sparc64nbsd_sigcontext_frame_unwind =
 {
+  "sparc64 netbsd sigcontext",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   sparc64nbsd_sigcontext_frame_this_id,

gdb/sparc64-obsd-tdep.c

@@ -222,6 +222,7 @@ sparc64obsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind sparc64obsd_frame_unwind =
 {
+  "sparc64 openbsd sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   sparc64obsd_frame_this_id,
@@ -305,6 +306,7 @@ sparc64obsd_trapframe_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind sparc64obsd_trapframe_unwind =
 {
+  "sparc64 openbsd trap",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   sparc64obsd_trapframe_this_id,

gdb/sparc64-sol2-tdep.c

@@ -185,6 +185,7 @@ sparc64_sol2_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind sparc64_sol2_sigtramp_frame_unwind =
 {
+  "sparc64 solaris sigtramp",
   SIGTRAMP_FRAME,
   default_frame_unwind_stop_reason,
   sparc64_sol2_sigtramp_frame_this_id,

gdb/sparc64-tdep.c

@@ -1141,6 +1141,7 @@ sparc64_frame_prev_register (struct frame_info *this_frame, void **this_cache,
 
 static const struct frame_unwind sparc64_frame_unwind =
 {
+  "sparc64 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   sparc64_frame_this_id,

gdb/tic6x-tdep.c

@@ -457,6 +457,7 @@ tic6x_frame_base_address (struct frame_info *this_frame, void **this_cache)
 
 static const struct frame_unwind tic6x_frame_unwind =
 {
+  "tic6x prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   tic6x_frame_this_id,
@@ -519,6 +520,7 @@ tic6x_stub_unwind_sniffer (const struct frame_unwind *self,
 
 static const struct frame_unwind tic6x_stub_unwind =
 {
+  "tic6x stub",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   tic6x_stub_this_id,

gdb/tilegx-tdep.c

@@ -905,6 +905,7 @@ tilegx_frame_base_address (struct frame_info *this_frame, void **this_cache)
 }
 
 static const struct frame_unwind tilegx_frame_unwind = {
+  "tilegx prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   tilegx_frame_this_id,

gdb/v850-tdep.c

@@ -1320,6 +1320,7 @@ v850_frame_this_id (struct frame_info *this_frame, void **this_cache,
 }
 
 static const struct frame_unwind v850_frame_unwind = {
+  "v850 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   v850_frame_this_id,

gdb/vax-tdep.c

@@ -390,6 +390,7 @@ vax_frame_prev_register (struct frame_info *this_frame,
 
 static const struct frame_unwind vax_frame_unwind =
 {
+  "vax prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   vax_frame_this_id,

gdb/xstormy16-tdep.c

@@ -736,6 +736,7 @@ xstormy16_frame_base_address (struct frame_info *this_frame, void **this_cache)
 }
 
 static const struct frame_unwind xstormy16_frame_unwind = {
+  "xstormy16 prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   xstormy16_frame_this_id,

gdb/xtensa-tdep.c

@@ -1499,6 +1499,7 @@ xtensa_frame_prev_register (struct frame_info *this_frame,
 static const struct frame_unwind
 xtensa_unwind =
 {
+  "xtensa prologue",
   NORMAL_FRAME,
   default_frame_unwind_stop_reason,
   xtensa_frame_this_id,