Patchwork Reproducible gcc builds, gfortran, and -grecord-gcc-switches

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Submitter Simon Baldwin
Date Aug. 21, 2012, 12:20 p.m.
Message ID <CAPTY64oBJDFVSUO=APY1KLUpmWcERDAdUVFvY1hCvkZVNeUxFA@mail.gmail.com>
Download mbox | patch
Permalink /patch/179052/
State New
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Comments

Simon Baldwin - Aug. 21, 2012, 12:20 p.m.
On 20 August 2012 16:45, Joseph S. Myers <joseph@codesourcery.com> wrote:
>
> On Mon, 20 Aug 2012, Simon Baldwin wrote:
>
> > > OPT_* for Fortran options only exist when the Fortran front-end is in the
> > > source tree (whether or not enabled).  I think we try to avoid knowingly
> > > breaking use cases where people remove some front ends from the source
> > > tree, although we don't actively test them and no longer provide split-up
> > > source tarballs.
> >
> > Thanks for the update.  Which fix should move forwards?
>
> I think the approach using a new option flag is the way to go, though the
> patch needs (at least) documentation for the new flag in options.texi.
>

Updated version appended below.  Okay for 4.8 trunk?

----------

Omit OPT_cpp_ from the DWARF producer string in gfortran.

Gfortran uses -cpp=<temporary file> internally, and with -grecord_gcc_switches
this command line switch is stored by default in object files.  This causes
problems with build and packaging systems that care about gcc binary
reproducibility and file checksums; the temporary file is different on each
compiler invocation.

Fixed by adding a new opt marker NoDWARFRecord and associated flag, filtering
options for this this setting when writing the producer string, and setting
this flag for fortran -cpp=<temporary file>

Tested for fortran (suppresses -cpp=...) and c (no effect).

gcc/ChangeLog
2012-08-21  Simon Baldwin  <simonb@google.com>

	* dwarf2out.c (gen_producer_string): Omit command line switch if
	CL_NO_DWARF_RECORD flag set.
	* opts.c (print_specific_help): Add CL_NO_DWARF_RECORD handling.
	* opts.h (CL_NO_DWARF_RECORD): New.
	* opt-functions.awk (switch_flags): Add NoDWARFRecord.
	* doc/options.texi: Document NoDWARFRecord option flag.
	* doc/invoke.texi: Document --help=nodwarfrecord.

gcc/fortran/ChangeLog
2012-08-21  Simon Baldwin  <simonb@google.com>

	* lang.opt (-cpp=): Mark flag NoDWARFRecord.



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Joseph S. Myers - Aug. 21, 2012, 3:18 p.m.
On Tue, 21 Aug 2012, Simon Baldwin wrote:

> Index: gcc/doc/options.texi
> ===================================================================
> --- gcc/doc/options.texi	(revision 190535)
> +++ gcc/doc/options.texi	(working copy)
> @@ -468,4 +468,8 @@ of @option{-@var{opt}}, if not explicitl
>  specify several different languages.  Each @var{language} must have
>  been declared by an earlier @code{Language} record.  @xref{Option file
>  format}.
> +
> +@item NoDWARFRecord
> +The option is added to the list of those omitted from the producer string
> +written by @option{-grecord-gcc-switches}.

Remove "added to the list of those" (which seems unnecessarily verbose).

> +@item @samp{nodwarfrecord}
> +Display only those options that are marked for addition to the list of
> +options omitted from @option{-grecord-gcc-switches}.

I don't think there's any need for special --help support for options with 
this flag; this flag is really an implementation detail.  (Thus, I think 
all the opts.c changes are unnecessary.)

Patch

Index: gcc/doc/options.texi
===================================================================
--- gcc/doc/options.texi	(revision 190535)
+++ gcc/doc/options.texi	(working copy)
@@ -468,4 +468,8 @@  of @option{-@var{opt}}, if not explicitl
 specify several different languages.  Each @var{language} must have
 been declared by an earlier @code{Language} record.  @xref{Option file
 format}.
+
+@item NoDWARFRecord
+The option is added to the list of those omitted from the producer string
+written by @option{-grecord-gcc-switches}.
 @end table
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi	(revision 190535)
+++ gcc/doc/invoke.texi	(working copy)
@@ -1330,6 +1330,10 @@  sign in the same continuous piece of tex
 @item @samp{separate}
 Display options taking an argument that appears as a separate word
 following the original option, such as: @samp{-o output-file}.
+
+@item @samp{nodwarfrecord}
+Display only those options that are marked for addition to the list of
+options omitted from @option{-grecord-gcc-switches}.
 @end table

 Thus for example to display all the undocumented target-specific
Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c	(revision 190535)
+++ gcc/dwarf2out.c	(working copy)
@@ -18101,6 +18101,9 @@  gen_producer_string (void)
 	/* Ignore these.  */
 	continue;
       default:
+        if (cl_options[save_decoded_options[j].opt_index].flags
+	    & CL_NO_DWARF_RECORD)
+	  continue;
         gcc_checking_assert (save_decoded_options[j].canonical_option[0][0]
 			     == '-');
         switch (save_decoded_options[j].canonical_option[0][1])
Index: gcc/opts.c
===================================================================
--- gcc/opts.c	(revision 190535)
+++ gcc/opts.c	(working copy)
@@ -1186,7 +1186,9 @@  print_specific_help (unsigned int includ
     {
       if (any_flags == 0)
 	{
-	  if (include_flags & CL_UNDOCUMENTED)
+	  if (include_flags & CL_NO_DWARF_RECORD)
+	    description = _("The following options are not recorded by DWARF");
+          else if (include_flags & CL_UNDOCUMENTED)
 	    description = _("The following options are not documented");
 	  else if (include_flags & CL_SEPARATE)
 	    description = _("The following options take separate arguments");
@@ -1292,7 +1294,7 @@  common_handle_option (struct gcc_options
 	/* Walk along the argument string, parsing each word in turn.
 	   The format is:
 	   arg = [^]{word}[,{arg}]
-	   word = {optimizers|target|warnings|undocumented|
+	   word = {optimizers|target|warnings|undocumented|nodwarfrecord|
 		   params|common|<language>}  */
 	while (* a != 0)
 	  {
@@ -1307,6 +1309,7 @@  common_handle_option (struct gcc_options
 	      { "target", CL_TARGET },
 	      { "warnings", CL_WARNING },
 	      { "undocumented", CL_UNDOCUMENTED },
+	      { "nodwarfrecord", CL_NO_DWARF_RECORD },
 	      { "params", CL_PARAMS },
 	      { "joined", CL_JOINED },
 	      { "separate", CL_SEPARATE },
Index: gcc/opts.h
===================================================================
--- gcc/opts.h	(revision 190535)
+++ gcc/opts.h	(working copy)
@@ -145,6 +145,7 @@  extern const unsigned int cl_lang_count;
 #define CL_JOINED		(1U << 22) /* If takes joined argument.  */
 #define CL_SEPARATE		(1U << 23) /* If takes a separate argument.  */
 #define CL_UNDOCUMENTED		(1U << 24) /* Do not output with --help.  */
+#define CL_NO_DWARF_RECORD	(1U << 25) /* Do not add to producer string.  */

 /* Flags for an enumerated option argument.  */
 #define CL_ENUM_CANONICAL	(1 << 0) /* Canonical for this value.  */
Index: gcc/fortran/lang.opt
===================================================================
--- gcc/fortran/lang.opt	(revision 190535)
+++ gcc/fortran/lang.opt	(working copy)
@@ -295,7 +295,7 @@  Fortran Negative(nocpp)
 Enable preprocessing

 cpp=
-Fortran Joined Negative(nocpp) Undocumented
+Fortran Joined Negative(nocpp) Undocumented NoDWARFRecord
 ; Internal option generated by specs from -cpp.

 nocpp
Index: gcc/opt-functions.awk
===================================================================
--- gcc/opt-functions.awk	(revision 190535)
+++ gcc/opt-functions.awk	(working copy)
@@ -103,6 +103,7 @@  function switch_flags (flags)
 	  test_flag("JoinedOrMissing", flags, " | CL_JOINED") \
 	  test_flag("Separate", flags, " | CL_SEPARATE") \
 	  test_flag("Undocumented", flags,  " | CL_UNDOCUMENTED") \
+	  test_flag("NoDWARFRecord", flags,  " | CL_NO_DWARF_RECORD") \
 	  test_flag("Warning", flags,  " | CL_WARNING") \
 	  test_flag("Optimization", flags,  " | CL_OPTIMIZATION")
 	sub( "^0 \\| ", "", result )