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

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Submitter Simon Baldwin
Date Aug. 24, 2012, 11:09 a.m.
Message ID <CAPTY64rMyTTZGP7A16PbOi8t6E5hjnEZCtc4naiLDG_F0wM4Hg@mail.gmail.com>
Download mbox | patch
Permalink /patch/179827/
State New
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Comments

Simon Baldwin - Aug. 24, 2012, 11:09 a.m.
On 21 August 2012 17:18, Joseph S. Myers <joseph@codesourcery.com> wrote:
>
> 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.)

Thanks, revised and shorter version below.  Please take another look when ready.

----------
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
2012-08-24  Simon Baldwin  <simonb@google.com>

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

gcc/fortran/ChangeLog
2012-08-24  Simon Baldwin  <simonb@google.com>

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



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Joseph S. Myers - Aug. 24, 2012, 2:48 p.m.
On Fri, 24 Aug 2012, Simon Baldwin wrote:

> gcc/ChangeLog
> 2012-08-24  Simon Baldwin  <simonb@google.com>
> 
> 	* dwarf2out.c (gen_producer_string): Omit command line switch if
> 	CL_NO_DWARF_RECORD flag set.
> 	* opts.h (CL_NO_DWARF_RECORD): New.
> 	* opt-functions.awk (switch_flags): Add NoDWARFRecord.
> 	* doc/options.texi: Document NoDWARFRecord option flag.
> 
> gcc/fortran/ChangeLog
> 2012-08-24  Simon Baldwin  <simonb@google.com>
> 
> 	* lang.opt (-cpp=): Mark flag NoDWARFRecord.

OK.

Patch

Index: gcc/doc/options.texi
===================================================================
--- gcc/doc/options.texi	(revision 190642)
+++ 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 omitted from the producer string written by
+@option{-grecord-gcc-switches}.
 @end table
Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c	(revision 190642)
+++ gcc/dwarf2out.c	(working copy)
@@ -18138,6 +18138,9 @@  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.h
===================================================================
--- gcc/opts.h	(revision 190642)
+++ 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 190642)
+++ 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 190642)
+++ 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 )