Re: Disassemble branch delay slot instructions automatically

["Maciej W. Rozycki" <macro at mips dot com>]

On Wed, 20 Jun 2007, Eli Zaretskii wrote:

> This is fine, but I think we should also document this in the user
> manual.

 Good point -- I hope my note is clear enough -- see below.

gdb/:
2007-06-21  Nigel Stephens  <nigel@mips.com>
            Maciej W. Rozycki  <macro@mips.com>

	* disasm.c (gdb_print_insn): Return the number of branch delay
	slot instructions too.
	* disasm.h (gdb_print_insn): Update prototype.
	* printcmd.c (branch_delay_insns): New variable to record the
	number of delay slot instructions after disassembling a branch.
	(print_formatted): Record the number of branch delay slot
	instructions.
	(do_examine): When disassembling, if the last instruction
	disassembled has any branch delay slots, then bump the count so
	that they get disassembled too.
	* tui/tui-disasm.c (tui_disassemble): Update the call to
	gdb_print_insn().
	* NEWS: Document the new behaviour.

gdb/doc/:
2007-06-21  Maciej W. Rozycki  <macro@mips.com>

	* gdb.texinfo (Examining Memory): Document the new behaviour.

gdb/gdbtk/:
2007-06-21  Maciej W. Rozycki  <macro@mips.com>

	* generic/gdbtk-cmds.c (gdbtk_load_asm): Update the call to
	gdb_print_insn().

 I have checked it in.

  Maciej

12235.diff
Index: binutils-quilt/src/gdb/printcmd.c
===================================================================
--- binutils-quilt.orig/src/gdb/printcmd.c	2007-06-21 13:39:03.000000000 +0100
+++ binutils-quilt/src/gdb/printcmd.c	2007-06-21 14:10:21.000000000 +0100
@@ -70,6 +70,10 @@
 
 static CORE_ADDR next_address;
 
+/* Number of delay instructions following current disassembled insn.  */
+
+static int branch_delay_insns;
+
 /* Last address examined.  */
 
 static CORE_ADDR last_examine_address;
@@ -277,8 +281,9 @@
 
       /* We often wrap here if there are long symbolic names.  */
       wrap_here ("    ");
-      next_address = VALUE_ADDRESS (val)
-	+ gdb_print_insn (VALUE_ADDRESS (val), stream);
+      next_address = (VALUE_ADDRESS (val)
+		      + gdb_print_insn (VALUE_ADDRESS (val), stream,
+					&branch_delay_insns));
       break;
 
     default:
@@ -800,6 +805,10 @@
 	    release_value (last_examine_value);
 
 	  print_formatted (last_examine_value, format, size, gdb_stdout);
+
+	  /* Display any branch delay slots following the final insn.  */
+	  if (format == 'i' && count == 1)
+	    count += branch_delay_insns;
 	}
       printf_filtered ("\n");
       gdb_flush (gdb_stdout);
Index: binutils-quilt/src/gdb/disasm.c
===================================================================
--- binutils-quilt.orig/src/gdb/disasm.c	2007-06-21 13:39:03.000000000 +0100
+++ binutils-quilt/src/gdb/disasm.c	2007-06-21 14:10:21.000000000 +0100
@@ -387,11 +387,24 @@
 }
 
 /* Print the instruction at address MEMADDR in debugged memory,
-   on STREAM.  Returns length of the instruction, in bytes.  */
+   on STREAM.  Returns the length of the instruction, in bytes,
+   and, if requested, the number of branch delay slot instructions.  */
 
 int
-gdb_print_insn (CORE_ADDR memaddr, struct ui_file *stream)
+gdb_print_insn (CORE_ADDR memaddr, struct ui_file *stream,
+		int *branch_delay_insns)
 {
-  struct disassemble_info di = gdb_disassemble_info (current_gdbarch, stream);
-  return gdbarch_print_insn (current_gdbarch, memaddr, &di);
+  struct disassemble_info di;
+  int length;
+
+  di = gdb_disassemble_info (current_gdbarch, stream);
+  length = gdbarch_print_insn (current_gdbarch, memaddr, &di);
+  if (branch_delay_insns)
+    {
+      if (di.insn_info_valid)
+	*branch_delay_insns = di.branch_delay_insns;
+      else
+	*branch_delay_insns = 0;
+    }
+  return length;
 }
Index: binutils-quilt/src/gdb/disasm.h
===================================================================
--- binutils-quilt.orig/src/gdb/disasm.h	2007-06-21 13:39:03.000000000 +0100
+++ binutils-quilt/src/gdb/disasm.h	2007-06-21 14:10:21.000000000 +0100
@@ -30,9 +30,12 @@
 			     int mixed_source_and_assembly,
 			     int how_many, CORE_ADDR low, CORE_ADDR high);
 
-/* Print the instruction at address MEMADDR in debugged memory, on
-   STREAM.  Returns length of the instruction, in bytes.  */
+/* Print the instruction at address MEMADDR in debugged memory,
+   on STREAM.  Returns the length of the instruction, in bytes,
+   and, if requested, the number of branch delay slot instructions.  */
 
-extern int gdb_print_insn (CORE_ADDR memaddr, struct ui_file *stream);
+extern int gdb_print_insn (CORE_ADDR memaddr,
+			   struct ui_file *stream,
+			   int *branch_delay_insns);
 
 #endif
Index: binutils-quilt/src/gdb/tui/tui-disasm.c
===================================================================
--- binutils-quilt.orig/src/gdb/tui/tui-disasm.c	2007-06-21 13:39:03.000000000 +0100
+++ binutils-quilt/src/gdb/tui/tui-disasm.c	2007-06-21 14:10:21.000000000 +0100
@@ -72,7 +72,7 @@
 
       ui_file_rewind (gdb_dis_out);
 
-      pc = pc + gdb_print_insn (pc, gdb_dis_out);
+      pc = pc + gdb_print_insn (pc, gdb_dis_out, NULL);
 
       asm_lines->insn = xstrdup (tui_file_get_strbuf (gdb_dis_out));
 
Index: binutils-quilt/src/gdb/gdbtk/generic/gdbtk-cmds.c
===================================================================
--- binutils-quilt.orig/src/gdb/gdbtk/generic/gdbtk-cmds.c	2007-06-21 13:39:03.000000000 +0100
+++ binutils-quilt/src/gdb/gdbtk/generic/gdbtk-cmds.c	2007-06-21 14:10:21.000000000 +0100
@@ -1895,7 +1895,7 @@
 
   result_ptr->obj_ptr = client_data->result_obj[2];
   /* FIXME: cagney/2003-09-08: This should use gdb_disassembly.  */
-  insn = gdb_print_insn (pc, gdb_stdout);
+  insn = gdb_print_insn (pc, gdb_stdout, NULL);
   gdb_flush (gdb_stdout);
 
   client_data->widget_line_no++;
Index: binutils-quilt/src/gdb/NEWS
===================================================================
--- binutils-quilt.orig/src/gdb/NEWS	2007-06-21 13:39:03.000000000 +0100
+++ binutils-quilt/src/gdb/NEWS	2007-06-21 14:10:21.000000000 +0100
@@ -41,6 +41,9 @@
 layout.  It also supports a TextSeg= and DataSeg= response when only
 segment base addresses (rather than offsets) are available.
 
+* The /i format now outputs any trailing branch delay slot instructions 
+immediately following the last instruction within the count specified.
+
 * New commands
 
 set remoteflow
Index: binutils-quilt/src/gdb/doc/gdb.texinfo
===================================================================
--- binutils-quilt.orig/src/gdb/doc/gdb.texinfo	2007-06-21 13:39:03.000000000 +0100
+++ binutils-quilt/src/gdb/doc/gdb.texinfo	2007-06-21 14:19:07.000000000 +0100
@@ -5861,9 +5861,12 @@
 Even though the unit size @var{u} is ignored for the formats @samp{s}
 and @samp{i}, you might still want to use a count @var{n}; for example,
 @samp{3i} specifies that you want to see three machine instructions,
-including any operands.  The command @code{disassemble} gives an
-alternative way of inspecting machine instructions; see @ref{Machine
-Code,,Source and Machine Code}.
+including any operands.  For convenience, especially when used with
+the @code{display} command, the @samp{i} format also prints branch delay
+slot instructions, if any, beyond the count specified, which immediately
+follow the last instruction that is within the count.  The command
+@code{disassemble} gives an alternative way of inspecting machine
+instructions; see @ref{Machine Code,,Source and Machine Code}.
 
 All the defaults for the arguments to @code{x} are designed to make it
 easy to continue scanning memory with minimal specifications each time