objdump/opcodes: add syntax highlighting to disassembler output

This commit adds the _option_ of having disassembler output syntax
highlighted in objdump.  This option is _off_ by default.  The new
command line options are:

  --disassembler-color=off		# The default.
  --disassembler-color=color
  --disassembler-color=extended-color

I have implemented two colour modes, using the same option names as we
use of --visualize-jumps, a basic 8-color mode ("color"), and an
extended 8bit color mode ("extended-color").

The syntax highlighting requires that each targets disassembler be
updated; each time the disassembler produces some output we now pass
through an additional parameter indicating what style should be
applied to the text.

As updating all target disassemblers is a large task, the old API is
maintained.  And so, a user of the disassembler (i.e. objdump, gdb)
must provide two functions, the current non-styled print function, and
a new, styled print function.

I don't currently have a plan for converting every single target
disassembler, my hope is that interested folk will update the
disassemblers they are interested in.  But it is possible some might
never get updated.

In this initial series I intend to convert the RISC-V disassembler
completely, and also do a partial conversion of the x86 disassembler.
Hopefully having the x86 disassembler at least partial converted will
allow more people to try this out easily and provide feedback.

In this commit I have focused on objdump.  The changes to GDB at this
point are the bare minimum required to get things compiling, GDB makes
no use of the styling information to provide any colors, that will
come later, if this commit is accepted.

This first commit in the series doesn't convert any target
disassemblers at all (the next two commits will update some targets),
so after this commit, the only color you will see in the disassembler
output, is that produced from objdump itself, e.g. from
objdump_print_addr_with_sym, where we print an address and a symbol
name, these are now printed with styling information, and so will have
colors applied (if the option is on).

Finally, my ability to pick "good" colors is ... well, terrible.  I'm
in no way committed to the colors I've picked here, so I encourage
people to suggest new colors, or wait for this commit to land, and
then patch the choice of colors.

I do have an idea about using possibly an environment variable to
allow the objdump colors to be customised, but I haven't done anything
like that in this commit, the color choices are just fixed in the code
for now.

binutils/ChangeLog:

	* NEWS: Mention new feature.
	* doc/binutils.texi (objdump): Describe --disassembler-color
	option.
	* objdump.c (disassembler_color): New global.
	(disassembler_extended_color): Likewise.
	(disassembler_in_comment): Likewise.
	(usage): Mention --disassembler-color option.
	(long_options): Add --disassembler-color option.
	(objdump_print_value): Use fprintf_styled_func instead of
	fprintf_func.
	(objdump_print_symname): Likewise.
	(objdump_print_addr_with_sym): Likewise.
	(objdump_color_for_disassembler_style): New function.
	(objdump_styled_sprintf): New function.
	(fprintf_styled): New function.
	(disassemble_jumps): Use disassemble_set_printf, and reset
	disassembler_in_comment.
	(null_styled_print): New function.
	(disassemble_bytes): Use disassemble_set_printf, and reset
	disassembler_in_comment.
	(disassemble_data): Update init_disassemble_info call.
	(main): Handle --disassembler-color option.

include/ChangeLog:

	* dis-asm.h (enum disassembler_style): New enum.
	(struct disassemble_info): Add fprintf_styled_func field, and
	created_styled_output field.
	(disassemble_set_printf): Declare.
	(init_disassemble_info): Add additional parameter.
	(INIT_DISASSEMBLE_INFO): Add additional parameter.

opcodes/ChangeLog:

	* dis-init.c (init_disassemble_info): Take extra parameter,
	initialize the new fprintf_styled_func and created_styled_output
	fields.
	* disassembler.c (disassemble_set_printf): New function definition.

1 files changed, 217 insertions, 32 deletions

diff --git a/binutils/objdump.c b/binutils/objdump.c
index 8e1c9cb..54c89a3 100644
--- a/binutils/objdump.c
+++ b/binutils/objdump.c
@@ -130,10 +130,19 @@ static bool visualize_jumps = false;	/* --visualize-jumps.  */
 static bool color_output = false;	/* --visualize-jumps=color.  */
 static bool extended_color_output = false; /* --visualize-jumps=extended-color.  */
 static int process_links = false;       /* --process-links.  */
+static bool disassembler_color = false; /* --disassembler-color=color.  */
+static bool disassembler_extended_color = false; /* --disassembler-color=extended-color.  */
 
 static int dump_any_debugging;
 static int demangle_flags = DMGL_ANSI | DMGL_PARAMS;
 
+/* This is reset to false each time we enter the disassembler, and set true
+   when the disassembler emits something in the dis_style_comment_start
+   style.  Once this is true, all further output on that line is done in
+   the comment style.  This only has an effect when disassembler coloring
+   is turned on.  */
+static bool disassembler_in_comment = false;
+
 /* A structure to record the sections mentioned in -j switches.  */
 struct only
 {
@@ -396,6 +405,10 @@ usage (FILE *stream, int status)
                                  Use extended 8-bit color codes\n"));
       fprintf (stream, _("\
       --visualize-jumps=off      Disable jump visualization\n\n"));
+      fprintf (stream, _("\
+      --disassembler-color=off   Disable disassembler color output.\n\n"));
+      fprintf (stream, _("\
+      --disassembler-color=color Use basic colors in disassembler output.\n\n"));
 
       list_supported_targets (program_name, stream);
       list_supported_architectures (program_name, stream);
@@ -437,7 +450,8 @@ enum option_values
     OPTION_CTF,
     OPTION_CTF_PARENT,
 #endif
-    OPTION_VISUALIZE_JUMPS
+    OPTION_VISUALIZE_JUMPS,
+    OPTION_DISASSEMBLER_COLOR
   };
 
 static struct option long_options[]=
@@ -503,6 +517,7 @@ static struct option long_options[]=
   {"version", no_argument, NULL, 'V'},
   {"visualize-jumps", optional_argument, 0, OPTION_VISUALIZE_JUMPS},
   {"wide", no_argument, NULL, 'w'},
+  {"disassembler-color", required_argument, NULL, OPTION_DISASSEMBLER_COLOR},
   {NULL, no_argument, NULL, 0}
 };
 
@@ -1246,7 +1261,7 @@ objdump_print_value (bfd_vma vma, struct disassemble_info *inf,
       if (*p == '\0')
 	--p;
     }
-  (*inf->fprintf_func) (inf->stream, "%s", p);
+  (*inf->fprintf_styled_func) (inf->stream, dis_style_address, "%s", p);
 }
 
 /* Print the name of a symbol.  */
@@ -1280,10 +1295,11 @@ objdump_print_symname (bfd *abfd, struct disassemble_info *inf,
 
   if (inf != NULL)
     {
-      (*inf->fprintf_func) (inf->stream, "%s", name);
+      (*inf->fprintf_styled_func) (inf->stream, dis_style_symbol, "%s", name);
       if (version_string && *version_string != '\0')
-	(*inf->fprintf_func) (inf->stream, hidden ? "@%s" : "@@%s",
-			      version_string);
+	(*inf->fprintf_styled_func) (inf->stream, dis_style_symbol,
+				     hidden ? "@%s" : "@@%s",
+				     version_string);
     }
   else
     {
@@ -1545,31 +1561,33 @@ objdump_print_addr_with_sym (bfd *abfd, asection *sec, asymbol *sym,
   if (!no_addresses)
     {
       objdump_print_value (vma, inf, skip_zeroes);
-      (*inf->fprintf_func) (inf->stream, " ");
+      (*inf->fprintf_styled_func) (inf->stream, dis_style_text, " ");
     }
 
   if (sym == NULL)
     {
       bfd_vma secaddr;
 
-      (*inf->fprintf_func) (inf->stream, "<%s",
-			    sanitize_string (bfd_section_name (sec)));
+      (*inf->fprintf_styled_func) (inf->stream, dis_style_text,"<");
+      (*inf->fprintf_styled_func) (inf->stream, dis_style_symbol, "%s",
+				   sanitize_string (bfd_section_name (sec)));
       secaddr = bfd_section_vma (sec);
       if (vma < secaddr)
 	{
-	  (*inf->fprintf_func) (inf->stream, "-0x");
+	  (*inf->fprintf_styled_func) (inf->stream, dis_style_immediate,
+				       "-0x");
 	  objdump_print_value (secaddr - vma, inf, true);
 	}
       else if (vma > secaddr)
 	{
-	  (*inf->fprintf_func) (inf->stream, "+0x");
+	  (*inf->fprintf_styled_func) (inf->stream, dis_style_immediate, "+0x");
 	  objdump_print_value (vma - secaddr, inf, true);
 	}
-      (*inf->fprintf_func) (inf->stream, ">");
+      (*inf->fprintf_styled_func) (inf->stream, dis_style_text, ">");
     }
   else
     {
-      (*inf->fprintf_func) (inf->stream, "<");
+      (*inf->fprintf_styled_func) (inf->stream, dis_style_text, "<");
 
       objdump_print_symname (abfd, inf, sym);
 
@@ -1586,21 +1604,22 @@ objdump_print_addr_with_sym (bfd *abfd, asection *sec, asymbol *sym,
 	;
       else if (bfd_asymbol_value (sym) > vma)
 	{
-	  (*inf->fprintf_func) (inf->stream, "-0x");
+	  (*inf->fprintf_styled_func) (inf->stream, dis_style_immediate,"-0x");
 	  objdump_print_value (bfd_asymbol_value (sym) - vma, inf, true);
 	}
       else if (vma > bfd_asymbol_value (sym))
 	{
-	  (*inf->fprintf_func) (inf->stream, "+0x");
+	  (*inf->fprintf_styled_func) (inf->stream, dis_style_immediate, "+0x");
 	  objdump_print_value (vma - bfd_asymbol_value (sym), inf, true);
 	}
 
-      (*inf->fprintf_func) (inf->stream, ">");
+      (*inf->fprintf_styled_func) (inf->stream, dis_style_text, ">");
     }
 
   if (display_file_offsets)
-    inf->fprintf_func (inf->stream, _(" (File Offset: 0x%lx)"),
-			(long int)(sec->filepos + (vma - sec->vma)));
+    inf->fprintf_styled_func (inf->stream, dis_style_text,
+			      _(" (File Offset: 0x%lx)"),
+			      (long int)(sec->filepos + (vma - sec->vma)));
 }
 
 /* Print an address (VMA), symbolically if possible.
@@ -2127,6 +2146,143 @@ objdump_sprintf (SFILE *f, const char *format, ...)
   return n;
 }
 
+/* Return an integer greater than, or equal to zero, representing the color
+   for STYLE, or -1 if no color should be used.  */
+
+static int
+objdump_color_for_disassembler_style (enum disassembler_style style)
+{
+  int color = -1;
+
+  if (style == dis_style_comment_start)
+    disassembler_in_comment = true;
+
+  if (disassembler_color)
+    {
+      if (disassembler_in_comment)
+	return color;
+
+      switch (style)
+	{
+	case dis_style_symbol: color = 32; break;
+        case dis_style_assembler_directive:
+	case dis_style_mnemonic: color = 33; break;
+	case dis_style_register: color = 34; break;
+	case dis_style_address:
+        case dis_style_address_offset:
+	case dis_style_immediate: color = 35; break;
+	default:
+	case dis_style_text: color = -1; break;
+	}
+    }
+  else if (disassembler_extended_color)
+    {
+      if (disassembler_in_comment)
+	return 250;
+
+      switch (style)
+	{
+	case dis_style_symbol: color = 40; break;
+        case dis_style_assembler_directive:
+	case dis_style_mnemonic: color = 142; break;
+	case dis_style_register: color = 27; break;
+	case dis_style_address:
+        case dis_style_address_offset:
+	case dis_style_immediate: color = 134; break;
+	default:
+	case dis_style_text: color = -1; break;
+	}
+    }
+
+  return color;
+}
+
+/* Like objdump_sprintf, but add in escape sequences to highlight the
+   content according to STYLE.  */
+
+static int ATTRIBUTE_PRINTF_3
+objdump_styled_sprintf (SFILE *f, enum disassembler_style style,
+			const char *format, ...)
+{
+  size_t n;
+  va_list args;
+  int color = objdump_color_for_disassembler_style (style);
+
+  if (color >= 0)
+    {
+      while (1)
+	{
+	  size_t space = f->alloc - f->pos;
+
+	  if (disassembler_color)
+	    n = snprintf (f->buffer + f->pos, space, "\033[%dm", color);
+	  else
+	    n = snprintf (f->buffer + f->pos, space, "\033[38;5;%dm", color);
+	  if (space > n)
+	    break;
+
+	  f->alloc = (f->alloc + n) * 2;
+	  f->buffer = (char *) xrealloc (f->buffer, f->alloc);
+	}
+      f->pos += n;
+    }
+
+  while (1)
+    {
+      size_t space = f->alloc - f->pos;
+
+      va_start (args, format);
+      n = vsnprintf (f->buffer + f->pos, space, format, args);
+      va_end (args);
+
+      if (space > n)
+	break;
+
+      f->alloc = (f->alloc + n) * 2;
+      f->buffer = (char *) xrealloc (f->buffer, f->alloc);
+    }
+  f->pos += n;
+
+  if (color >= 0)
+    {
+      while (1)
+	{
+	  size_t space = f->alloc - f->pos;
+
+	  n = snprintf (f->buffer + f->pos, space, "\033[0m");
+
+	  if (space > n)
+	    break;
+
+	  f->alloc = (f->alloc + n) * 2;
+	  f->buffer = (char *) xrealloc (f->buffer, f->alloc);
+	}
+      f->pos += n;
+    }
+
+  return n;
+}
+
+/* We discard the styling information here.  This function is only used
+   when objdump is printing auxiliary information, the symbol headers, and
+   disassembly address, or the bytes of the disassembled instruction.  We
+   don't (currently) apply styling to any of this stuff, so, for now, just
+   print the content with no additional style added.  */
+
+static int ATTRIBUTE_PRINTF_3
+fprintf_styled (FILE *f, enum disassembler_style style ATTRIBUTE_UNUSED,
+		const char *fmt, ...)
+{
+  int res;
+  va_list ap;
+
+  va_start (ap, fmt);
+  res = vfprintf (f, fmt, ap);
+  va_end (ap);
+
+  return res;
+}
+
 /* Code for generating (colored) diagrams of control flow start and end
    points.  */
 
@@ -2558,8 +2714,8 @@ disassemble_jumps (struct disassemble_info * inf,
   sfile.pos = 0;
 
   inf->insn_info_valid = 0;
-  inf->fprintf_func = (fprintf_ftype) objdump_sprintf;
-  inf->stream = &sfile;
+  disassemble_set_printf (inf, &sfile, (fprintf_ftype) objdump_sprintf,
+			  (fprintf_styled_ftype) objdump_styled_sprintf);
 
   addr_offset = start_offset;
   while (addr_offset < stop_offset)
@@ -2621,6 +2777,7 @@ disassemble_jumps (struct disassemble_info * inf,
 
       /* Extract jump information.  */
       inf->insn_info_valid = 0;
+      disassembler_in_comment = false;
       octets = (*disassemble_fn) (section->vma + addr_offset, inf);
       /* Test if a jump was detected.  */
       if (inf->insn_info_valid
@@ -2641,9 +2798,8 @@ disassemble_jumps (struct disassemble_info * inf,
       addr_offset += octets / opb;
     }
 
-  inf->fprintf_func = (fprintf_ftype) fprintf;
-  inf->stream = stdout;
-
+  disassemble_set_printf (inf, (void *) stdout, (fprintf_ftype) fprintf,
+			  (fprintf_styled_ftype) fprintf_styled);
   free (sfile.buffer);
 
   /* Merge jumps.  */
@@ -2736,6 +2892,17 @@ null_print (const void * stream ATTRIBUTE_UNUSED, const char * format ATTRIBUTE_
   return 1;
 }
 
+/* Like null_print, but takes the extra STYLE argument.  As this is not
+   going to print anything, the extra argument is just ignored.  */
+
+static int
+null_styled_print (const void * stream ATTRIBUTE_UNUSED,
+		   enum disassembler_style style ATTRIBUTE_UNUSED,
+		   const char * format ATTRIBUTE_UNUSED, ...)
+{
+  return 1;
+}
+
 /* Print out jump visualization.  */
 
 static void
@@ -2946,8 +3113,9 @@ disassemble_bytes (struct disassemble_info *inf,
 	      int insn_size;
 
 	      sfile.pos = 0;
-	      inf->fprintf_func = (fprintf_ftype) objdump_sprintf;
-	      inf->stream = &sfile;
+	      disassemble_set_printf
+		(inf, &sfile, (fprintf_ftype) objdump_sprintf,
+		 (fprintf_styled_ftype) objdump_styled_sprintf);
 	      inf->bytes_per_line = 0;
 	      inf->bytes_per_chunk = 0;
 	      inf->flags = ((disassemble_all ? DISASSEMBLE_DATA : 0)
@@ -2989,10 +3157,15 @@ disassemble_bytes (struct disassemble_info *inf,
 			     twice, but we only do this when there is a high
 			     probability that there is a reloc that will
 			     affect the instruction.  */
-			  inf->fprintf_func = (fprintf_ftype) null_print;
+			  disassemble_set_printf
+			    (inf, inf->stream, (fprintf_ftype) null_print,
+			     (fprintf_styled_ftype) null_styled_print);
 			  insn_size = disassemble_fn (section->vma
 						      + addr_offset, inf);
-			  inf->fprintf_func = (fprintf_ftype) objdump_sprintf;
+			  disassemble_set_printf
+			    (inf, inf->stream,
+			     (fprintf_ftype) objdump_sprintf,
+			     (fprintf_styled_ftype) objdump_styled_sprintf);
 			}
 		    }
 
@@ -3017,12 +3190,13 @@ disassemble_bytes (struct disassemble_info *inf,
 		inf->stop_vma = section->vma + stop_offset;
 
 	      inf->stop_offset = stop_offset;
+	      disassembler_in_comment = false;
 	      insn_size = (*disassemble_fn) (section->vma + addr_offset, inf);
 	      octets = insn_size;
 
 	      inf->stop_vma = 0;
-	      inf->fprintf_func = (fprintf_ftype) fprintf;
-	      inf->stream = stdout;
+	      disassemble_set_printf (inf, stdout, (fprintf_ftype) fprintf,
+				      (fprintf_styled_ftype) fprintf_styled);
 	      if (insn_width == 0 && inf->bytes_per_line != 0)
 		octets_per_line = inf->bytes_per_line;
 	      if (insn_size < (int) opb)
@@ -3583,8 +3757,9 @@ disassemble_section (bfd *abfd, asection *section, void *inf)
 	      sf.alloc = strlen (sym->name) + 40;
 	      sf.buffer = (char*) xmalloc (sf.alloc);
 	      sf.pos = 0;
-	      di.fprintf_func = (fprintf_ftype) objdump_sprintf;
-	      di.stream = &sf;
+	      disassemble_set_printf
+		(&di, &sf, (fprintf_ftype) objdump_sprintf,
+		 (fprintf_styled_ftype) objdump_styled_sprintf);
 
 	      objdump_print_symname (abfd, &di, sym);
 
@@ -3653,8 +3828,8 @@ disassemble_data (bfd *abfd)
       ++sorted_symcount;
     }
 
-  init_disassemble_info (&disasm_info, stdout, (fprintf_ftype) fprintf);
-
+  init_disassemble_info (&disasm_info, stdout, (fprintf_ftype) fprintf,
+			 (fprintf_styled_ftype) fprintf_styled);
   disasm_info.application_data = (void *) &aux;
   aux.abfd = abfd;
   aux.require_sec = false;
@@ -5495,6 +5670,16 @@ main (int argc, char **argv)
 		nonfatal (_("unrecognized argument to --visualize-option"));
 	    }
 	  break;
+	case OPTION_DISASSEMBLER_COLOR:
+	  if (streq (optarg, "off"))
+	    disassembler_color = false;
+	  else if (streq (optarg, "color"))
+	    disassembler_color = true;
+	  else if (streq (optarg, "extended-color"))
+	    disassembler_extended_color = true;
+	  else
+	    nonfatal (_("unrecognized argument to --disassembler-color"));
+	  break;
 	case 'E':
 	  if (strcmp (optarg, "B") == 0)
 	    endian = BFD_ENDIAN_BIG;