Re: [Patch] Do not call the linker if we are creating precompiled header files

[Steve Ellcey <sellcey at cavium dot com>]

Ping^2

Steve Ellcey
sellcey@cavium.com

On Thu, 2018-05-17 at 14:50 -0700, Steve Ellcey wrote:
> Ping.
> 
> Steve Ellcey
> sellcey@cavium.com
> 
> 
> On Wed, 2018-05-02 at 12:47 -0700, Steve Ellcey wrote:
> > 
> > This is a new version of a patch I sent out last year to stop gcc from
> > trying to do a link when creating precompiled headers and a linker
> > flag is also given.
> > 
> > When I build and test GCC I also build glibc and then I run the GCC tests
> > with -Wl,-rpath and -Wl,--dynamic-linker so that I don't have to install
> > glibc and the compiler in the default locations.  When I do this some
> > precompiled header tests fail because the existance of the linker flags
> > causes the compiler to try and call the linker when we really just want to
> > create pch files.
> > 
> > I tracked this down to driver::maybe_run_linker where it sees the linker
> > flags and increments num_linker_inputs, this causes the routine to call
> > the linker.   This patch checks to see if we are creating precompiled
> > header files and avoids calling the linker in that case.
> > 
> > I tested this with the GCC testsuite and got no regressions, OK to
> > checkin?
> > 
> > Steve Ellcey
> > sellcey@cavium.com
> > 
> > 
> > 2018-05-02  Steve Ellcey  <sellcey@cavium.com>
> > 
> > 	* gcc.c (create_pch_flag): New variable.
> > 	(driver::prepare_infiles): Set create_pch_flag
> > 	when we are creating precompiled headers.
> > 	(driver::maybe_run_linker): Do not link if
> > 	create_pch_flag is set.
> > 	(driver::finalize): Reset create_pch_flag.
> > 
> > 
> > diff --git a/gcc/gcc.c b/gcc/gcc.c
> > index a716f70..ca986cf 100644
> > --- a/gcc/gcc.c
> > +++ b/gcc/gcc.c
> > @@ -208,6 +208,9 @@ int is_cpp_driver;
> >  /* Flag set to nonzero if an @file argument has been supplied to
> > gcc.  */
> >  static bool at_file_supplied;
> >  
> > +/* Flag set to nonzero if we are generating a precompiled
> > header.  */
> > +static bool create_pch_flag;
> > +
> >  /* Definition of string containing the arguments given to
> > configure.  */
> >  #include "configargs.h"
> >  
> > @@ -8095,8 +8098,15 @@ driver::prepare_infiles ()
> >  						   strlen (name),
> >  						   infiles[i].lang
> > ua
> > ge);
> >  
> > -      if (compiler && !(compiler->combinable))
> > -	combine_inputs = false;
> > +      if (compiler)
> > +	{
> > +	  if (!(compiler->combinable))
> > +	    combine_inputs = false;
> > +
> > +	  if ((strcmp(compiler->suffix, "@c-header") == 0)
> > +	      || (strcmp(compiler->suffix, "@c++-header") == 0))
> > +	    create_pch_flag = true;
> > +	}
> >  
> >        if (lang_n_infiles > 0 && compiler != input_file_compiler
> >  	  && infiles[i].language && infiles[i].language[0] != '*')
> > @@ -8282,6 +8292,10 @@ driver::maybe_run_linker (const char *argv0)
> > const
> >    int linker_was_run = 0;
> >    int num_linker_inputs;
> >  
> > +  /* If we are creating a precompiled header, do not run the
> > linker.  */
> > +  if (create_pch_flag)
> > +    return;
> > +
> >    /* Determine if there are any linker input files.  */
> >    num_linker_inputs = 0;
> >    for (i = 0; (int) i < n_infiles; i++)
> > @@ -10052,6 +10066,7 @@ driver::finalize ()
> >  
> >    is_cpp_driver = 0;
> >    at_file_supplied = 0;
> > +  create_pch_flag = 0;
> >    print_help_list = 0;
> >    print_version = 0;
> >    verbose_only_flag = 0;