2004-10-31 Orjan Friberg <organ.friberg@axis.com>

	    Andrew Cagney  <cagney@gnu.org>

	* gdbarch.sh (single_step_through_delay): Add.
	* gdbarch.h, gdbarch.c: Re-generate.
	* config/mips/tm-mips.h (STEP_SKIPS_DELAY_P, STEP_SKIPS_DELAY)
	(mips_step_skips_delay): Delete.
	* mips-tdep.c (mips_single_step_through_delay): Replace
	mips_step_skips_delay.
	(mips_gdbarch_init): Set single_step_through_delay.
	(mips_dump_tdep): Do not print STEP_SKIPS_DELAY.

7 files changed, 107 insertions, 28 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f8bb86a..e50e86d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,15 @@
+2004-10-31  Orjan Friberg <organ.friberg@axis.com>
+	    Andrew Cagney  <cagney@gnu.org>
+
+	* gdbarch.sh (single_step_through_delay): Add.
+	* gdbarch.h, gdbarch.c: Re-generate.
+	* config/mips/tm-mips.h (STEP_SKIPS_DELAY_P, STEP_SKIPS_DELAY)
+	(mips_step_skips_delay): Delete.
+	* mips-tdep.c (mips_single_step_through_delay): Replace
+	mips_step_skips_delay.
+	(mips_gdbarch_init): Set single_step_through_delay.
+	(mips_dump_tdep): Do not print STEP_SKIPS_DELAY.
+	
 2004-10-31  Mark Kettenis  <kettenis@gnu.org>
 
 	* tramp-frame.c (tramp_frame_prepend_unwinder): Set unwinder type
diff --git a/gdb/config/mips/tm-mips.h b/gdb/config/mips/tm-mips.h
index 0830342..09af61d 100644
--- a/gdb/config/mips/tm-mips.h
+++ b/gdb/config/mips/tm-mips.h
@@ -33,12 +33,6 @@ struct symbol;
 struct type;
 struct value;
 
-/* Return non-zero if PC points to an instruction which will cause a step
-   to execute both the instruction at PC and an instruction at PC+4.  */
-extern int mips_step_skips_delay (CORE_ADDR);
-#define STEP_SKIPS_DELAY_P (1)
-#define STEP_SKIPS_DELAY(pc) (mips_step_skips_delay (pc))
-
 /* Special symbol found in blocks associated with routines.  We can
    hang mdebug_extra_func_info's off of this.  */
 
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index 7eb4aeb..e822fa6 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -211,6 +211,7 @@ struct gdbarch
   gdbarch_addr_bits_remove_ftype *addr_bits_remove;
   gdbarch_smash_text_address_ftype *smash_text_address;
   gdbarch_software_single_step_ftype *software_single_step;
+  gdbarch_single_step_through_delay_ftype *single_step_through_delay;
   gdbarch_print_insn_ftype *print_insn;
   gdbarch_skip_trampoline_code_ftype *skip_trampoline_code;
   gdbarch_skip_solib_resolver_ftype *skip_solib_resolver;
@@ -337,6 +338,7 @@ struct gdbarch startup_gdbarch =
   0,  /* addr_bits_remove */
   0,  /* smash_text_address */
   0,  /* software_single_step */
+  0,  /* single_step_through_delay */
   0,  /* print_insn */
   0,  /* skip_trampoline_code */
   generic_skip_solib_resolver,  /* skip_solib_resolver */
@@ -591,6 +593,7 @@ verify_gdbarch (struct gdbarch *current_gdbarch)
   /* Skip verify of addr_bits_remove, invalid_p == 0 */
   /* Skip verify of smash_text_address, invalid_p == 0 */
   /* Skip verify of software_single_step, has predicate */
+  /* Skip verify of single_step_through_delay, has predicate */
   if (current_gdbarch->print_insn == 0)
     fprintf_unfiltered (log, "\n\tprint_insn");
   /* Skip verify of skip_trampoline_code, invalid_p == 0 */
@@ -1516,6 +1519,12 @@ gdbarch_dump (struct gdbarch *current_gdbarch, struct ui_file *file)
   fprintf_unfiltered (file,
                       "gdbarch_dump: short_bit = %s\n",
                       paddr_d (current_gdbarch->short_bit));
+  fprintf_unfiltered (file,
+                      "gdbarch_dump: gdbarch_single_step_through_delay_p() = %d\n",
+                      gdbarch_single_step_through_delay_p (current_gdbarch));
+  fprintf_unfiltered (file,
+                      "gdbarch_dump: single_step_through_delay = <0x%lx>\n",
+                      (long) current_gdbarch->single_step_through_delay);
 #ifdef SKIP_PROLOGUE
   fprintf_unfiltered (file,
                       "gdbarch_dump: %s # %s\n",
@@ -3346,6 +3355,30 @@ set_gdbarch_software_single_step (struct gdbarch *gdbarch,
 }
 
 int
+gdbarch_single_step_through_delay_p (struct gdbarch *gdbarch)
+{
+  gdb_assert (gdbarch != NULL);
+  return gdbarch->single_step_through_delay != NULL;
+}
+
+int
+gdbarch_single_step_through_delay (struct gdbarch *gdbarch, struct frame_info *frame)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->single_step_through_delay != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_single_step_through_delay called\n");
+  return gdbarch->single_step_through_delay (gdbarch, frame);
+}
+
+void
+set_gdbarch_single_step_through_delay (struct gdbarch *gdbarch,
+                                       gdbarch_single_step_through_delay_ftype single_step_through_delay)
+{
+  gdbarch->single_step_through_delay = single_step_through_delay;
+}
+
+int
 gdbarch_print_insn (struct gdbarch *gdbarch, bfd_vma vma, struct disassemble_info *info)
 {
   gdb_assert (gdbarch != NULL);
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index 78b27ba..8ff296c 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -1218,6 +1218,15 @@ extern void set_gdbarch_software_single_step (struct gdbarch *gdbarch, gdbarch_s
 #define SOFTWARE_SINGLE_STEP(sig, insert_breakpoints_p) (gdbarch_software_single_step (current_gdbarch, sig, insert_breakpoints_p))
 #endif
 
+/* Return non-zero if the processor is executing a delay slot and a
+   further single-step is needed before the instruction finishes. */
+
+extern int gdbarch_single_step_through_delay_p (struct gdbarch *gdbarch);
+
+typedef int (gdbarch_single_step_through_delay_ftype) (struct gdbarch *gdbarch, struct frame_info *frame);
+extern int gdbarch_single_step_through_delay (struct gdbarch *gdbarch, struct frame_info *frame);
+extern void set_gdbarch_single_step_through_delay (struct gdbarch *gdbarch, gdbarch_single_step_through_delay_ftype *single_step_through_delay);
+
 /* FIXME: cagney/2003-08-28: Need to find a better way of selecting the
    disassembler.  Perhaps objdump can handle it? */
 
diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index 3ffb85e..fec4c7a 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -611,6 +611,9 @@ f:=:CORE_ADDR:smash_text_address:CORE_ADDR addr:addr::core_addr_identity::0
 # FIXME/cagney/2001-01-18: The logic is backwards.  It should be asking if the target can
 # single step.  If not, then implement single step using breakpoints.
 F:=:void:software_single_step:enum target_signal sig, int insert_breakpoints_p:sig, insert_breakpoints_p
+# Return non-zero if the processor is executing a delay slot and a
+# further single-step is needed before the instruction finishes.
+M::int:single_step_through_delay:struct frame_info *frame:frame
 # FIXME: cagney/2003-08-28: Need to find a better way of selecting the
 # disassembler.  Perhaps objdump can handle it?
 f:TARGET_PRINT_INSN:int:print_insn:bfd_vma vma, struct disassemble_info *info:vma, info::0:
diff --git a/gdb/infrun.c b/gdb/infrun.c
index d35ecde..396a616 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -714,24 +714,17 @@ proceed (CORE_ADDR addr, enum target_signal siggnal, int step)
 
   if (addr == (CORE_ADDR) -1)
     {
-      /* If there is a breakpoint at the address we will resume at,
-         step one instruction before inserting breakpoints
-         so that we do not stop right away (and report a second
-         hit at this breakpoint).  */
-
       if (read_pc () == stop_pc && breakpoint_here_p (read_pc ()))
+	/* There is a breakpoint at the address we will resume at,
+	   step one instruction before inserting breakpoints so that
+	   we do not stop right away (and report a second hit at this
+	   breakpoint).  */
 	oneproc = 1;
-
-#ifndef STEP_SKIPS_DELAY
-#define STEP_SKIPS_DELAY(pc) (0)
-#define STEP_SKIPS_DELAY_P (0)
-#endif
-      /* Check breakpoint_here_p first, because breakpoint_here_p is fast
-         (it just checks internal GDB data structures) and STEP_SKIPS_DELAY
-         is slow (it needs to read memory from the target).  */
-      if (STEP_SKIPS_DELAY_P
-	  && breakpoint_here_p (read_pc () + 4)
-	  && STEP_SKIPS_DELAY (read_pc ()))
+      else if (gdbarch_single_step_through_delay_p (current_gdbarch)
+              && gdbarch_single_step_through_delay (current_gdbarch,
+                                                    get_current_frame ()))
+	/* We stepped onto an instruction that needs to be stepped
+	   again before re-inserting the breakpoint, do so.  */
 	oneproc = 1;
     }
   else
@@ -1781,6 +1774,39 @@ handle_inferior_event (struct execution_control_state *ecs)
   stopped_by_random_signal = 0;
   breakpoints_failed = 0;
 
+  if (stop_signal == TARGET_SIGNAL_TRAP
+      && trap_expected
+      && gdbarch_single_step_through_delay_p (current_gdbarch)
+      && currently_stepping (ecs))
+    {
+      /* We're trying to step of a breakpoint.  Turns out that we're
+	 also on an instruction that needs to be stepped multiple
+	 times before it's been fully executing. E.g., architectures
+	 with a delay slot.  It needs to be stepped twice, once for
+	 the instruction and once for the delay slot.  */
+      int step_through_delay
+	= gdbarch_single_step_through_delay (current_gdbarch,
+					     get_current_frame ());
+      if (step_range_end == 0 && step_through_delay)
+	{
+	  /* The user issued a continue when stopped at a breakpoint.
+	     Set up for another trap and get out of here.  */
+         ecs->another_trap = 1;
+         keep_going (ecs);
+         return;
+	}
+      else if (step_through_delay)
+	{
+	  /* The user issued a step when stopped at a breakpoint.
+	     Maybe we should stop, maybe we should not - the delay
+	     slot *might* correspond to a line of source.  In any
+	     case, don't decide that here, just set ecs->another_trap,
+	     making sure we single-step again before breakpoints are
+	     re-inserted.  */
+	  ecs->another_trap = 1;
+	}
+    }
+
   /* Look at the cause of the stop, and decide what to do.
      The alternatives are:
      1) break; to really stop and return to the debugger,
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
index 047abe5..686b8b1 100644
--- a/gdb/mips-tdep.c
+++ b/gdb/mips-tdep.c
@@ -4142,16 +4142,19 @@ is_delayed (unsigned long insn)
 }
 
 int
-mips_step_skips_delay (CORE_ADDR pc)
+mips_single_step_through_delay (struct gdbarch *gdbarch,
+				struct frame_info *frame)
 {
+  CORE_ADDR pc = get_frame_pc (frame);
   char buf[MIPS_INSN32_SIZE];
 
   /* There is no branch delay slot on MIPS16.  */
   if (mips_pc_is_mips16 (pc))
     return 0;
 
-  if (target_read_memory (pc, buf, sizeof buf) != 0)
-    /* If error reading memory, guess that it is not a delayed branch.  */
+  if (!safe_frame_unwind_memory (frame, pc, buf, sizeof buf))
+    /* If error reading memory, guess that it is not a delayed
+       branch.  */
     return 0;
   return is_delayed (extract_unsigned_integer (buf, sizeof buf));
 }
@@ -5097,6 +5100,8 @@ mips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
       set_gdbarch_in_solib_return_trampoline (gdbarch, mips_in_solib_return_trampoline);
     }
 
+  set_gdbarch_single_step_through_delay (gdbarch, mips_single_step_through_delay);
+
   /* Hook in OS ABI-specific overrides, if they have been registered.  */
   gdbarch_init_osabi (info, gdbarch);
 
@@ -5305,9 +5310,6 @@ mips_dump_tdep (struct gdbarch *current_gdbarch, struct ui_file *file)
 		      "mips_dump_tdep: STEP_SKIPS_DELAY # %s\n",
 		      XSTRING (STEP_SKIPS_DELAY (PC)));
   fprintf_unfiltered (file,
-		      "mips_dump_tdep: STEP_SKIPS_DELAY_P = %d\n",
-		      STEP_SKIPS_DELAY_P);
-  fprintf_unfiltered (file,
 		      "mips_dump_tdep: STOPPED_BY_WATCHPOINT # %s\n",
 		      XSTRING (STOPPED_BY_WATCHPOINT (WS)));
   fprintf_unfiltered (file,