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, 83 insertions, 5 deletions

diff --git a/include/dis-asm.h b/include/dis-asm.h
index 3175924..4f91df1 100644
--- a/include/dis-asm.h
+++ b/include/dis-asm.h
@@ -35,8 +35,6 @@ extern "C" {
 #include <string.h>
 #include "bfd.h"
 
-  typedef int (*fprintf_ftype) (void *, const char*, ...) ATTRIBUTE_FPTR_PRINTF_2;
-
 enum dis_insn_type
 {
   dis_noninsn,			/* Not a valid instruction.  */
@@ -49,6 +47,76 @@ enum dis_insn_type
   dis_dref2			/* Two data references in instruction.  */
 };
 
+/* When printing styled disassembler output, this describes what style
+   should be used.  */
+
+enum disassembler_style
+{
+  /* This is the default style, use this for any additional syntax
+     (e.g. commas between operands, brackets, etc), or just as a default if
+     no other style seems appropriate.  */
+  dis_style_text,
+
+  /* Use this for all instruction mnemonics, or aliases for mnemonics.
+     These should be things that correspond to real machine
+     instructions.  */
+  dis_style_mnemonic,
+
+  /* For things that aren't real machine instructions, but rather
+     assembler directives, e.g. .byte, etc.  */
+  dis_style_assembler_directive,
+
+  /* Use this for any register names.  This may or may-not include any
+     register prefix, e.g. '$', '%', at the discretion of the target,
+     though within each target the choice to include prefixes for not
+     should be kept consistent.  If the prefix is not printed with this
+     style, then dis_style_text should be used.  */
+  dis_style_register,
+
+  /* Use this for any constant values used within instructions or
+     directives, unless the value is an absolute address, or an offset
+     that will be added to an address (no matter where the address comes
+     from) before use.  This style may, or may-not be used for any
+     prefix to the immediate value, e.g. '$', at the discretion of the
+     target, though within each target the choice to include these
+     prefixes should be kept consistent.  */
+  dis_style_immediate,
+
+  /* The style for the numerical representation of an absolute address.
+     Anything that is an address offset should use the immediate style.
+     This style may, or may-not be used for any prefix to the immediate
+     value, e.g. '$', at the discretion of the target, though within
+     each target the choice to include these prefixes should be kept
+     consistent.  */
+  dis_style_address,
+
+  /* The style for any constant value within an instruction or directive
+     that represents an offset that will be added to an address before
+     use.  This style may, or may-not be used for any prefix to the
+     immediate value, e.g. '$', at the discretion of the target, though
+     within each target the choice to include these prefixes should be
+     kept consistent.  */
+  dis_style_address_offset,
+
+  /* The style for a symbol's name.  The numerical address of a symbol
+     should use the address style above, this style is reserved for the
+     name.  */
+  dis_style_symbol,
+
+  /* The start of a comment that runs to the end of the line.  Anything
+     printed after a comment start might be styled differently,
+     e.g. everything might be styled as a comment, regardless of the
+     actual style used.  The disassembler itself should not try to adjust
+     the style emitted for comment content, e.g. an address emitted within
+     a comment should still be given dis_style_address, in this way it is
+     up to the user of the disassembler to decide how comments should be
+     styled.  */
+  dis_style_comment_start
+};
+
+typedef int (*fprintf_ftype) (void *, const char*, ...) ATTRIBUTE_FPTR_PRINTF_2;
+typedef int (*fprintf_styled_ftype) (void *, enum disassembler_style, const char*, ...) ATTRIBUTE_FPTR_PRINTF_3;
+
 /* This struct is passed into the instruction decoding routine,
    and is passed back out into each callback.  The various fields are used
    for conveying information from your main routine into your callbacks,
@@ -62,6 +130,7 @@ enum dis_insn_type
 typedef struct disassemble_info
 {
   fprintf_ftype fprintf_func;
+  fprintf_styled_ftype fprintf_styled_func;
   void *stream;
   void *application_data;
 
@@ -228,6 +297,9 @@ typedef struct disassemble_info
      disassembling such as the way mapping symbols are found on AArch64.  */
   bfd_vma stop_offset;
 
+  /* Set to true if the disassembler applied styling to the output,
+     otherwise, set to false.  */
+  bool created_styled_output;
 } disassemble_info;
 
 /* This struct is used to pass information about valid disassembler
@@ -337,6 +409,10 @@ extern void disassemble_init_for_target (struct disassemble_info *);
 /* Tidy any memory allocated by targets, such as info->private_data.  */
 extern void disassemble_free_target (struct disassemble_info *);
 
+/* Set the basic disassembler print functions.  */
+extern void disassemble_set_printf (struct disassemble_info *, void *,
+				    fprintf_ftype, fprintf_styled_ftype);
+
 /* Document any target specific options available from the disassembler.  */
 extern void disassembler_usage (FILE *);
 
@@ -394,11 +470,13 @@ extern bool generic_symbol_is_valid
 /* Method to initialize a disassemble_info struct.  This should be
    called by all applications creating such a struct.  */
 extern void init_disassemble_info (struct disassemble_info *dinfo, void *stream,
-				   fprintf_ftype fprintf_func);
+				   fprintf_ftype fprintf_func,
+				   fprintf_styled_ftype fprintf_styled_func);
 
 /* For compatibility with existing code.  */
-#define INIT_DISASSEMBLE_INFO(INFO, STREAM, FPRINTF_FUNC) \
-  init_disassemble_info (&(INFO), (STREAM), (fprintf_ftype) (FPRINTF_FUNC))
+#define INIT_DISASSEMBLE_INFO(INFO, STREAM, FPRINTF_FUNC, FPRINTF_STYLED_FUNC)  \
+  init_disassemble_info (&(INFO), (STREAM), (fprintf_ftype) (FPRINTF_FUNC), \
+			 (fprintf_styled_ftype) (FPRINTF_STYLED_FUNC))
 
 #ifdef __cplusplus
 }