On Fri, Jan 24, 2020 at 7:04 AM Prathamesh Kulkarni
<prathamesh.kulka...@linaro.org> wrote:
>
> On Mon, 20 Jan 2020 at 15:44, Richard Biener <richard.guent...@gmail.com>
> wrote:
> >
> > On Wed, Jan 8, 2020 at 11:20 AM Prathamesh Kulkarni
> > <prathamesh.kulka...@linaro.org> wrote:
> > >
> > > On Tue, 5 Nov 2019 at 17:38, Richard Biener <richard.guent...@gmail.com>
> > > wrote:
> > > >
> > > > On Tue, Nov 5, 2019 at 12:17 AM Kugan Vivekanandarajah
> > > > <kugan.vivekanandara...@linaro.org> wrote:
> > > > >
> > > > > Hi,
> > > > > Thanks for the review.
> > > > >
> > > > > On Tue, 5 Nov 2019 at 03:57, H.J. Lu <hjl.to...@gmail.com> wrote:
> > > > > >
> > > > > > On Sun, Nov 3, 2019 at 6:45 PM Kugan Vivekanandarajah
> > > > > > <kugan.vivekanandara...@linaro.org> wrote:
> > > > > > >
> > > > > > > Thanks for the reviews.
> > > > > > >
> > > > > > >
> > > > > > > On Sat, 2 Nov 2019 at 02:49, H.J. Lu <hjl.to...@gmail.com> wrote:
> > > > > > > >
> > > > > > > > On Thu, Oct 31, 2019 at 6:33 PM Kugan Vivekanandarajah
> > > > > > > > <kugan.vivekanandara...@linaro.org> wrote:
> > > > > > > > >
> > > > > > > > > On Wed, 30 Oct 2019 at 03:11, H.J. Lu <hjl.to...@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > On Sun, Oct 27, 2019 at 6:33 PM Kugan Vivekanandarajah
> > > > > > > > > > <kugan.vivekanandara...@linaro.org> wrote:
> > > > > > > > > > >
> > > > > > > > > > > Hi Richard,
> > > > > > > > > > >
> > > > > > > > > > > Thanks for the review.
> > > > > > > > > > >
> > > > > > > > > > > On Wed, 23 Oct 2019 at 23:07, Richard Biener
> > > > > > > > > > > <richard.guent...@gmail.com> wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > On Mon, Oct 21, 2019 at 10:04 AM Kugan Vivekanandarajah
> > > > > > > > > > > > <kugan.vivekanandara...@linaro.org> wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > Hi Richard,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks for the pointers.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Fri, 11 Oct 2019 at 22:33, Richard Biener
> > > > > > > > > > > > > <richard.guent...@gmail.com> wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Fri, Oct 11, 2019 at 6:15 AM Kugan
> > > > > > > > > > > > > > Vivekanandarajah
> > > > > > > > > > > > > > <kugan.vivekanandara...@linaro.org> wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Richard,
> > > > > > > > > > > > > > > Thanks for the review.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Wed, 2 Oct 2019 at 20:41, Richard Biener
> > > > > > > > > > > > > > > <richard.guent...@gmail.com> wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Wed, Oct 2, 2019 at 10:39 AM Kugan
> > > > > > > > > > > > > > > > Vivekanandarajah
> > > > > > > > > > > > > > > > <kugan.vivekanandara...@linaro.org> wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > As mentioned in the PR, attached patch adds
> > > > > > > > > > > > > > > > > COLLECT_AS_OPTIONS for
> > > > > > > > > > > > > > > > > passing assembler options specified with -Wa,
> > > > > > > > > > > > > > > > > to the link-time driver.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > The proposed solution only works for uniform
> > > > > > > > > > > > > > > > > -Wa options across all
> > > > > > > > > > > > > > > > > TUs. As mentioned by Richard Biener,
> > > > > > > > > > > > > > > > > supporting non-uniform -Wa flags
> > > > > > > > > > > > > > > > > would require either adjusting partitioning
> > > > > > > > > > > > > > > > > according to flags or
> > > > > > > > > > > > > > > > > emitting multiple object files from a single
> > > > > > > > > > > > > > > > > LTRANS CU. We could
> > > > > > > > > > > > > > > > > consider this as a follow up.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Bootstrapped and regression tests on
> > > > > > > > > > > > > > > > > arm-linux-gcc. Is this OK for trunk?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > While it works for your simple cases it is
> > > > > > > > > > > > > > > > unlikely to work in practice since
> > > > > > > > > > > > > > > > your implementation needs the assembler options
> > > > > > > > > > > > > > > > be present at the link
> > > > > > > > > > > > > > > > command line. I agree that this might be the
> > > > > > > > > > > > > > > > way for people to go when
> > > > > > > > > > > > > > > > they face the issue but then it needs to be
> > > > > > > > > > > > > > > > documented somewhere
> > > > > > > > > > > > > > > > in the manual.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > That is, with COLLECT_AS_OPTION (why singular?
> > > > > > > > > > > > > > > > I'd expected
> > > > > > > > > > > > > > > > COLLECT_AS_OPTIONS) available to cc1 we could
> > > > > > > > > > > > > > > > stream this string
> > > > > > > > > > > > > > > > to lto_options and re-materialize it at link
> > > > > > > > > > > > > > > > time (and diagnose mismatches
> > > > > > > > > > > > > > > > even if we like).
> > > > > > > > > > > > > > > OK. I will try to implement this. So the idea is
> > > > > > > > > > > > > > > if we provide
> > > > > > > > > > > > > > > -Wa,options as part of the lto compile, this
> > > > > > > > > > > > > > > should be available
> > > > > > > > > > > > > > > during link time. Like in:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > arm-linux-gnueabihf-gcc -march=armv7-a -mthumb
> > > > > > > > > > > > > > > -O2 -flto
> > > > > > > > > > > > > > > -Wa,-mimplicit-it=always,-mthumb -c test.c
> > > > > > > > > > > > > > > arm-linux-gnueabihf-gcc -flto test.o
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I am not sure where should we stream this.
> > > > > > > > > > > > > > > Currently, cl_optimization
> > > > > > > > > > > > > > > has all the optimization flag provided for
> > > > > > > > > > > > > > > compiler and it is
> > > > > > > > > > > > > > > autogenerated and all the flags are integer
> > > > > > > > > > > > > > > values. Do you have any
> > > > > > > > > > > > > > > preference or example where this should be done.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > In lto_write_options, I'd simply append the
> > > > > > > > > > > > > > contents of COLLECT_AS_OPTIONS
> > > > > > > > > > > > > > (with -Wa, prepended to each of them), then recover
> > > > > > > > > > > > > > them in lto-wrapper
> > > > > > > > > > > > > > for each TU and pass them down to the LTRANS
> > > > > > > > > > > > > > compiles (if they agree
> > > > > > > > > > > > > > for all TUs, otherwise I'd warn and drop them).
> > > > > > > > > > > > >
> > > > > > > > > > > > > Attached patch streams it and also make sure that the
> > > > > > > > > > > > > options are the
> > > > > > > > > > > > > same for all the TUs. Maybe it is a bit restrictive.
> > > > > > > > > > > > >
> > > > > > > > > > > > > What is the best place to document
> > > > > > > > > > > > > COLLECT_AS_OPTIONS. We don't seem
> > > > > > > > > > > > > to document COLLECT_GCC_OPTIONS anywhere ?
> > > > > > > > > > > >
> > > > > > > > > > > > Nowhere, it's an implementation detail then.
> > > > > > > > > > > >
> > > > > > > > > > > > > Attached patch passes regression and also fixes the
> > > > > > > > > > > > > original ARM
> > > > > > > > > > > > > kernel build issue with tumb2.
> > > > > > > > > > > >
> > > > > > > > > > > > Did you try this with multiple assembler options? I
> > > > > > > > > > > > see you stream
> > > > > > > > > > > > them as -Wa,-mfpu=xyz,-mthumb but then compare the whole
> > > > > > > > > > > > option strings so a mismatch with -Wa,-mthumb,-mfpu=xyz
> > > > > > > > > > > > would be
> > > > > > > > > > > > diagnosed. If there's a spec induced -Wa option do we
> > > > > > > > > > > > get to see
> > > > > > > > > > > > that as well? I can imagine -march=xyz enabling a -Wa
> > > > > > > > > > > > option
> > > > > > > > > > > > for example.
> > > > > > > > > > > >
> > > > > > > > > > > > + *collect_as = XNEWVEC (char, strlen
> > > > > > > > > > > > (args_text) + 1);
> > > > > > > > > > > > + strcpy (*collect_as, args_text);
> > > > > > > > > > > >
> > > > > > > > > > > > there's strdup. Btw, I'm not sure why you don't simply
> > > > > > > > > > > > leave
> > > > > > > > > > > > the -Wa option in the merged options [individually] and
> > > > > > > > > > > > match
> > > > > > > > > > > > them up but go the route of comparing strings and
> > > > > > > > > > > > carrying that
> > > > > > > > > > > > along separately. I think that would be much better.
> > > > > > > > > > >
> > > > > > > > > > > Is attached patch which does this is OK?
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Don't you need to also handle -Xassembler? Since -Wa,
> > > > > > > > > > doesn't work with comma in
> > > > > > > > > > assembler options, like -mfoo=foo1,foo2, one needs to use
> > > > > > > > > >
> > > > > > > > > > -Xassembler -mfoo=foo1,foo2
> > > > > > > > > >
> > > > > > > > > > to pass -mfoo=foo1,foo2 to assembler.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > gcc -flto -O2 -Wa,-mcpu=zzz1 -mcpu=xxx1 -c foo.c
> > > > > > > > > gcc -flto -O2 -Wa,-mcpu=zzz2 -mcpu=xxx2 -c bar.c
> > > > > > > > >
> > > > > > > > > What should be the option we should provide for the final
> > > > > > > > > gcc -flto foo.o bar.o -o out
> > > > > > > > >
> > > > > > > > > I think our ultimate aim is to handle this in LTO
> > > > > > > > > partitioning. That
> > > > > > > > > is, we should create partitioning such that each partition
> > > > > > > > > has the
> > > > > > > > > same -Wa options. This could also handle -Xassembler
> > > > > > > > > -mfoo=foo1,foo2
> > > > > > > > > which H.J. Lu wanted. We need to modify the heuristics and do
> > > > > > > > > some
> > > > > > > > > performance testing.
> > > > > > > > >
> > > > > > > > > In the meantime we could push a simpler solution which is to
> > > > > > > > > accept
> > > > > > > > > -Wa option if they are identical. This would fix at least
> > > > > > > > > some of the
> > > > > > > > > reported cases. Trying to work out what is compatible
> > > > > > > > > options, even if
> > > > > > > > > we ask the back-end to do this, is not a straightforward
> > > > > > > > > strategy and
> > > > > > > > > can be a maintenance nightmare. Unless we can query GNU AS
> > > > > > > > > somehow. If
> > > > > > > > > I am missing something please let me know.
> > > > > > > >
> > > > > > > > +/* Store switches specified for as with -Wa in
> > > > > > > > COLLECT_AS_OPTIONS
> > > > > > > > + and place that in the environment. */
> > > > > > > > +static void
> > > > > > > > +putenv_COLLECT_AS_OPTIONS (vec<char_p> vec)
> > > > > > > > +{
> > > > > > > > + unsigned ix;
> > > > > > > > + char *opt;
> > > > > > > > + int len = vec.length ();
> > > > > > > > +
> > > > > > > > + if (!len)
> > > > > > > > + return;
> > > > > > > > +
> > > > > > > > + obstack_init (&collect_obstack);
> > > > > > > > + obstack_grow (&collect_obstack, "COLLECT_AS_OPTIONS=",
> > > > > > > > + sizeof ("COLLECT_AS_OPTIONS=") - 1);
> > > > > > > > + obstack_grow (&collect_obstack, "-Wa,", strlen ("-Wa,"));
> > > > > > > > +
> > > > > > > > + FOR_EACH_VEC_ELT (vec, ix, opt)
> > > > > > > > + {
> > > > > > > > + obstack_grow (&collect_obstack, opt, strlen (opt));
> > > > > > > > + --len;
> > > > > > > > + if (len)
> > > > > > > > + obstack_grow (&collect_obstack, ",", strlen (","));
> > > > > > > > + }
> > > > > > > > +
> > > > > > > > + xputenv (XOBFINISH (&collect_obstack, char *));
> > > > > > > >
> > > > > > > > This missed the null terminator.
> > > > > > >
> > > > > > > Attached patch addresses the review comments I got so far.
> > > > > > >
> > > > > >
> > > > > > + if (len)
> > > > > > + obstack_grow (&collect_obstack, ",", strlen (","));
> > > > > >
> > > > > > Why not sizeof (",") - 1?
> > > > > I guess I copied and pasted it from elsewhere else. We seem to use
> > > > > both. I have changed it now.
> > > > >
> > > > > >
> > > > > > diff --git a/gcc/lto-wrapper.c b/gcc/lto-wrapper.c
> > > > > > index 9a7bbd0c022..148c52906d1 100644
> > > > > > --- a/gcc/lto-wrapper.c
> > > > > > +++ b/gcc/lto-wrapper.c
> > > > > > @@ -253,6 +253,11 @@ merge_and_complain (struct cl_decoded_option
> > > > > > **decoded_options,
> > > > > > break;
> > > > > >
> > > > > > default:
> > > > > > + if (foption->opt_index == OPT_Wa_)
> > > > > > + {
> > > > > > + append_option (decoded_options, decoded_options_count,
> > > > > > foption);
> > > > > > + break;
> > > > > > + }
> > > > > > if (!(cl_options[foption->opt_index].flags & CL_TARGET))
> > > > > > break;
> > > > > >
> > > > > > Why not use "case OPT_Wa_:" here?
> > > > > Done.
> > > > > >
> > > > > > For
> > > > > >
> > > > > > + static const char *collect_as;
> > > > > > + for (unsigned int j = 1; j < count; ++j)
> > > > > > + {
> > > > > > + struct cl_decoded_option *option = &opts[j];
> > > > > > + if (j == 1)
> > > > > > + collect_as = NULL;
> > > > > >
> > > > > > why not simply
> > > > > >
> > > > > > const char *collect_as = NULL?
> > > > >
> > > > > I wanted to make sure that if we call this from multiple places, it
> > > > > still works. I guess it is still going to be the same. I have changed
> > > > > it now as you have suggested.
> > > > >
> > > > > Is this revised patch OK? I will do a fresh bootstrap and regression
> > > > > testing before committing.
> > > >
> > > > In putenv_COLLECT_AS_OPTIONS you'll happily make
> > > > -Wa,-march=foo,bar out of -Xassembler -march=foo,bar which
> > > > will later cause us to fail to assemble with unknown assembler options.
> > > > May I suggest to instead always use -Xassembler syntax in
> > > > COLLECT_AS_OPTIONS? Please also make sure to quote
> > > > options the same way set_collect_gcc_options does
> > > > (with '', separated by spaces). Then the lto-opts.c part
> > > > becomes "easier" as you can simply copy the string to the
> > > > obstack without wrapping it again with append_to_collect_gcc_options.
> > > >
> > > > In lto-wrapper you then only have to handle OPT_Xassembler.
> > > >
> > > > You simply end up appending _all_ assembler options in order
> > > > of TUs processed by lto-wrapper to the final command (N times
> > > > even if exactly the same). I'm also not sure how you can check
> > > > for positional equivalence (or if we even should). With -Wa
> > > > we could compare the full option string but with separate -Xassembler
> > > > we're having a more difficult task here. OTOH your patch doesn't
> > > > do any comparing here.
> > > >
> > > > Your append_compiler_wa_options should be merged into
> > > > append_compiler_options, passing -Xassembler through.
> > > Hi Richard,
> > > Since Kugan has left Linaro (and GCC), I'd like to take up this task.
> > > I have modified his patch to always pass assembler options via
> > > -Xassembler.
> > > Does it look OK ?
> > >
> > > I am not sure how we should proceed with error-checking for Xassembler ?
> > > In lto-wrapper, I suppose, we can append all Xassembler options for a
> > > TU into a single string, and then
> > > do strcmp similar to previous patch(es) doing strcmp for -Wa options
> > > string, although not sure if that's a good idea.
> >
> > I think there are multiple issues with the main one being how to
> > actually interpret -Xassembler in the LTO context.
> >
> > First let me point out some bits in the COLLECT_AS_OPTIONS parts.
> >
> > + FOR_EACH_VEC_ELT (vec, ix, opt)
> > + {
> > + obstack_grow (&collect_obstack, "\'-Xassembler\' ",
> > + strlen ("\'-Xassembler\' "));
> >
> > quoting of -Xassembler is not necessary.
> >
> > + obstack_1grow (&collect_obstack, '\'');
> > + obstack_grow (&collect_obstack, opt, strlen (opt));
> > + obstack_grow (&collect_obstack, "\' ", 2);
> >
> > This adds a stray space after the last option.
> >
> > Note that COLLECT_AS_OPTIONS gives the impression of listing
> > assembler options but the above adds GCC driver options - assembler
> > options prepended by -Xassembler. IMHO we should drop the
> > -Xassembler emission from the above loop and simply emit the plain
> > assembler options. That requires adjustments to lto_write_options,
> > adding those -Xassembler options.
> >
> > + char *asm_opts = XOBFINISH (&collect_obstack, char *);
> > + xputenv (XOBFINISH (&collect_obstack, char *));
> > + xputenv (asm_opts);
> >
> > That outputs the ENV twice.
> >
> > Note that we record things like --version or --help into
> > assembler_options but I'm not sure the merging of assembler
> > options should be affected on whether one TU was compiled with -v
> > or not. This might mean simply pruning those in lto-options.c
> > (not listing them in COLLECT_AS_OPTIONS wouldn't tell the truth).
> >
> > @@ -252,6 +252,10 @@ merge_and_complain (struct cl_decoded_option
> > **decoded_options,
> > case OPT_SPECIAL_input_file:
> > break;
> >
> > + case OPT_Xassembler:
> > + append_option (decoded_options, decoded_options_count, foption);
> > + break;
> > +
> >
> > this adds the same option over-and-over again, possibly becoming unwieldly.
> > Most of the function also assumes that option position isn't important
> > which might or might not be true. So I think a better course of action
> > would be to not handle Xassembler in the above loop but do a separate
> > one checking 1:1 equality of passed assembler options like
> >
> > /* Verify -Xassembler options are the same on all TUs. */
> > j = 0;
> > i = 0;
> > unsigned Xascount = 0;
> > while (j < *decoded_options_count && i < fdeconded_options_count)
> > {
> > while (fdecoded_options[i].opt_index != OPT_Xassembler) ++i;
> > same for *decoded_options
> > if (stray Xassembler on one side)
> > fatal_error (...);
> > if (strcmp (...) != 0)
> > fatal_error (...);
> > }
> >
> > which means we use the -Xassembler options from the first TU and
> > above only verify those match those from all other TUs.
> Hi Richard,
> Thanks for the suggestions, I tried to address them in the attached patch.
> It now gives errors on following cases during link command:
>
> 1]
> gcc -O -flto -c -Xassembler -mfoo f1.c
> gcc -O -flto -c f2.c
> gcc -O -flto f1.o f2.o
>
> 2]
> gcc -O -flto -c -Xassembler -mfoo f1.c
> gcc -O -flto -c -Xassembler -mbar f2.c
> gcc -O -flto f1.o f2.o
>
> 3]
> gcc -O -flto -c -Xassembler -mfoo -Xassembler -mbar f1.c
> gcc -O -flto -c -Xassembler -mbar -Xassembler -mfoo f2.c
> gcc -O -flto f1.o f2.o
>
> 4]
> gcc -O -flto -c f1.c
> gcc -O -flto -Xassembler -mfoo f1.c
> gcc -O -flto f1.o f2.o
>
> 5]
> gcc -O -flto -Xassembler -mfoo f1.c
> gcc -O -flto -Xassembler -mfoo f2.c
> gcc -O -flto -Xassembler -mbar f1.o f2.o
>
> The following correct case works:
> gcc -O -flto -Xassembler -mfoo f1.c
> gcc -O -flto -Xassembler -mfoo f2.c
> gcc -O -flto f1.o f2.o
I think 5] should work as well and behave as -mfoo -mbar at assembler time.
Add
6]
gcc -O -flto f1.c
gcc -O -flto f2.c
gcc -O -flto -Xassembler -mfoo f1.o f2.o
which should work as well (I think even this use doesn't work right now?)
> Could you please suggest how to add the above cases in dejaGNU format ?
> I am not sure how to write multiple files test with dejaGNU.
look at multi-file testcases in gcc.dg/lto/, use testcase_0.c testcase_1.c,
you can use dg-additional-options to pass -Xassembler (but eventually
that doesn't work on the first TU), also there's some additional option
for the link step directive (just look into the existing tests).
> Also, do you think it's better if we append xassembler options to
> COLLECT_GCC itself rather
> than maintaining COLLECT_AS_OPTIONS with "Xassembler" prepended ?
> Because in both lto_write_options,
> and run_gcc, I am reconstructing "-Xassembler" <opt> for each opt in
> COLLECT_AS_OPTIONS.
>
> I am not quite sure how Xassembler options were added to
> fdecoded_options because I am not appending them
> explicitly. IIUC, find_and_merge_options will add -Xassembler to
> fdecoded_options when it's NULL ?
> if (!fdecoded_options)
> {
> fdecoded_options = f2decoded_options;
> fdecoded_options_count = f2decoded_options_count;
> }
> since merge_and_complain does not handle OPT_Xassembler.
Yes.
Comments on the patch. First avoid <algorithm>, just use MIN/MAX
if really needed. I'd elide xassembler_opts[_count]. For 6] you want
to unconditionally append the options.
In find_and_merge_options I'd have avoided xassembler_opts[_count]
by simply adding another nested loop over both decoded options
requiring matching up OPT_Xassembler 1:1.
Richard.
>
> Thanks,
> Prathamesh
> >
> > Richard.
> >
> > > Thanks,
> > > Prathamesh
> > > >
> > > > Thanks,
> > > > Richard.
> > > >
> > > > > Thanks,
> > > > > Kugan
> > > > >
> > > > > >
> > > > > >
> > > > > > H.J.
