Re: stabs.texinfo update for macro define/undefine

[David Taylor <dtaylor at emc dot com>]

> Date: Tue, 31 Oct 2006 06:19:33 +0200
> Message-Id: <uejsp6rsa.fsf@gnu.org>
> From: Eli Zaretskii <eliz@gnu.org>
> To: David Taylor <dtaylor@emc.com>
> Cc: gdb-patches@sourceware.org
> 
> > cc: Eli Zaretskii <eliz@gnu.org>
> > Date: Mon, 30 Oct 2006 17:25:21 -0500
> > From: David Taylor <dtaylor@emc.com>
> > 
> > Patch to add information about recording macro define and undefine
> > information in stabs.
> 
> Thanks.

You're welcome.

> > +@node Macro define and undefine
> > +@chapter Representation of #define and #undef
> > +
> > +Macro define and undefine.
> 
> This last sentence is redundant (and actually isn't even a sentence).

Deleted.

> > +information, supported on some systems.  (e.g., with -g3 -gstabs when
> 
> Please put command-line options in @option.

Done.

> > +using gcc).
> 
> Please use GCC instead of gcc.

Done.

> > +A @code{#define @var{macro-name} @var{macro-body}} is represented with
> > +an @code{N_MAC_DEFINE} stab with a string field of
> > +@code{@var{macro-name} @var{macro-body}}.
> > +@findex N_MAC_DEFINE
> > +
> > +An @code{#undef @var{macro-name}} is represented with an
> > +@code{N_MAC_UNDEF} stabs with a string field of simply
> > +@code{@var{macro-name}}.
> > +@findex N_MAC_UNDEF
> > +
> > +For both @code{N_MAC_DEFINE} and @code{N_MAC_UNDEF}, the desc field is
> > +the line number within the file where the corresponding @code{#define}
> > +or @code{#undef} occurred.
> > +@findex N_MAC_DEFINE
> > +@findex N_MAC_UNDEF
> 
> It is not useful to have two identical index entries that point to the
> same page.  In this case, I don't see the need for the second pair of
> @findex entries here.

In case the second chunk of text ended up on a different page than the
first chunk.  I'll delete it.

> > +@end example
> > +
> > +produces the following stabs (as well as many others):
> 
> You need a @noindent before this line, since you don't want it to be
> indented as if it were a new paragraph.

Done.

> > +@example
> > +    .stabs	"NONE 42",54,0,1,0                      # 54 is N_MAC_DEFINE
> > +    .stabs	"TWO(a,b) (a + (a) + 2 * b)",54,0,2,0   # 54 is N_MAC_DEFINE
> > +    .stabs	"ONE(c) (c + 19)",54,0,3,0              # 54 is N_MAC_DEFINE
> > +    .stabs	"ONE",58,0,10,0                         # 58 is N_MAC_UNDEF
> > +    .stabs	"ONE(c) (c + 23)",54,0,11,0             # 54 is N_MAC_DEFINE
> > +@end example
> 
> These lines are too long: they will overflow the page margin in the
> printed version of the manual.  I suggest to remove the comments and
> instead explain the meaning of the constants in a separate text.
> (Didn't I tell you this when you first posted the suggested text?)

You mentioned it, but I guess I misunderstood.  I ran both `make dvi'
and `make info' and looked at the resulting files.  The info file
stayed in fewer than 80 columns; I didn't see any TeX complaints about
an overfull hbox, nor did the dvi file have a black box on any of
those lines.  So, I guessed that they looked too long but were
actually okay.

In the future, how should I test to make sure that the lines are not
too long?

For this, how about:

    @example
        .stabs  "NONE 42",54,0,1,0
        .stabs  "TWO(a,b) (a + (a) + 2 * b)",54,0,2,0
        .stabs  "ONE(c) (c + 19)",54,0,3,0
        .stabs  "ONE",58,0,10,0
        .stabs  "ONE(c) (c + 23)",54,0,11,0
    @end example

    NOTE: In the example above, @code{54} is @code{N_MAC_DEFINE} and @code{58}
    is @code{N_MAC_UNDEF}.

?  This is the text in the patch attached below.

> Please also post the ChangeLog entry for the patch.

Done.

> With these changes, this can go in.  Thanks.

Thanks.  I don't have write after approval privileges.

Here's an updated patch:

gdb/doc/ChangeLog entry:

2006-10-31  David Taylor  <dtaylor@emc.com>

	* stabs.texinfo (Macro define and undefine): New node describing
	stabs for #define and #undef.

Index: stabs.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/stabs.texinfo,v
retrieving revision 1.18
diff -u -r1.18 stabs.texinfo
--- stabs.texinfo	2 Aug 2006 03:31:21 -0000	1.18
+++ stabs.texinfo	31 Oct 2006 14:12:55 -0000
@@ -67,6 +67,7 @@
 * Constants::			Constants
 * Variables::
 * Types::			Type definitions
+* Macro define and undefine::	Representation of #define and #undef
 * Symbol Tables::		Symbol information in symbol tables
 * Cplusplus::			Stabs specific to C++
 * Stab Types::			Symbol types in a.out files
@@ -2220,6 +2221,70 @@
 The variable defines a new type, 24, which is a pointer to another new
 type, 25, which is a function returning @code{int}.
 
+@node Macro define and undefine
+@chapter Representation of #define and #undef
+
+This section describes the stabs support for macro define and undefine
+information, supported on some systems.  (e.g., with @option{-g3}
+@option{-gstabs} when using GCC).
+
+A @code{#define @var{macro-name} @var{macro-body}} is represented with
+an @code{N_MAC_DEFINE} stab with a string field of
+@code{@var{macro-name} @var{macro-body}}.
+@findex N_MAC_DEFINE
+
+An @code{#undef @var{macro-name}} is represented with an
+@code{N_MAC_UNDEF} stabs with a string field of simply
+@code{@var{macro-name}}.
+@findex N_MAC_UNDEF
+
+For both @code{N_MAC_DEFINE} and @code{N_MAC_UNDEF}, the desc field is
+the line number within the file where the corresponding @code{#define}
+or @code{#undef} occurred.
+
+For example, the following C code:
+
+@example
+    #define NONE	42
+    #define TWO(a, b)	(a + (a) + 2 * b)
+    #define ONE(c)	(c + 19)
+
+    main(int argc, char *argv[])
+    @{
+      func(NONE, TWO(10, 11));
+      func(NONE, ONE(23));
+
+    #undef ONE
+    #define ONE(c)	(c + 23)
+
+      func(NONE, ONE(-23));
+
+      return (0);
+    @}
+
+    int global;
+
+    func(int arg1, int arg2)
+    @{
+      global = arg1 + arg2;
+    @}
+@end example
+
+@noindent
+produces the following stabs (as well as many others):
+
+@example
+    .stabs	"NONE 42",54,0,1,0
+    .stabs	"TWO(a,b) (a + (a) + 2 * b)",54,0,2,0
+    .stabs	"ONE(c) (c + 19)",54,0,3,0
+    .stabs	"ONE",58,0,10,0
+    .stabs	"ONE(c) (c + 23)",54,0,11,0
+@end example
+
+@noindent
+NOTE: In the above example, @code{54} is @code{N_MAC_DEFINE} and
+@code{58} is @code{N_MAC_UNDEF}.
+
 @node Symbol Tables
 @chapter Symbol Information in Symbol Tables
 
@@ -3276,11 +3341,17 @@
 @item 0x34     N_NOMAP
 No DST map; see @ref{N_NOMAP}.
 
+@item 0x36     N_MAC_DEFINE
+Name and body of a @code{#define}d macro; see @ref{Macro define and undefine}.
+
 @c FIXME: describe this solaris feature in the body of the text (see
 @c comments in include/aout/stab.def).
 @item 0x38 N_OBJ
 Object file (Solaris2).
 
+@item 0x3a     N_MAC_UNDEF
+Name of an @code{#undef}ed macro; see @ref{Macro define and undefine}.
+
 @c See include/aout/stab.def for (a little) more info.
 @item 0x3c N_OPT
 Debugger options (Solaris2).