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.
Thanks,
Prathamesh
>
> Thanks,
> Richard.
>
> > Thanks,
> > Kugan
> >
> > >
> > >
> > > H.J.
diff --git a/gcc/gcc.c b/gcc/gcc.c
index 4428d50c390..8dab511dba3 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -5242,6 +5242,36 @@ do_specs_vec (vec<char_p> vec)
}
}
+/* Add options passed via -Xassembler or -Wa to COLLECT_AS_OPTIONS. */
+
+static void
+putenv_COLLECT_AS_OPTIONS (vec<char_p> vec)
+{
+ if (vec.is_empty ())
+ return;
+
+ obstack_init (&collect_obstack);
+ obstack_grow (&collect_obstack, "COLLECT_AS_OPTIONS=",
+ strlen ("COLLECT_AS_OPTIONS="));
+
+ char *opt;
+ unsigned ix;
+
+ FOR_EACH_VEC_ELT (vec, ix, opt)
+ {
+ obstack_grow (&collect_obstack, "\'-Xassembler\' ",
+ strlen ("\'-Xassembler\' "));
+ obstack_1grow (&collect_obstack, '\'');
+ obstack_grow (&collect_obstack, opt, strlen (opt));
+ obstack_grow (&collect_obstack, "\' ", 2);
+ }
+
+ obstack_1grow (&collect_obstack, '\0');
+ char *asm_opts = XOBFINISH (&collect_obstack, char *);
+ xputenv (XOBFINISH (&collect_obstack, char *));
+ xputenv (asm_opts);
+}
+
/* Process the sub-spec SPEC as a portion of a larger spec.
This is like processing a whole spec except that we do
not initialize at the beginning and we do not supply a
@@ -7363,6 +7393,7 @@ driver::main (int argc, char **argv)
global_initializations ();
build_multilib_strings ();
set_up_specs ();
+ putenv_COLLECT_AS_OPTIONS (assembler_options);
putenv_COLLECT_GCC (argv[0]);
maybe_putenv_COLLECT_LTO_WRAPPER ();
maybe_putenv_OFFLOAD_TARGETS ();
diff --git a/gcc/lto-opts.c b/gcc/lto-opts.c
index 99c6fe53923..41b00baef5f 100644
--- a/gcc/lto-opts.c
+++ b/gcc/lto-opts.c
@@ -166,8 +166,20 @@ lto_write_options (void)
obstack_grow (&temporary_obstack, "\0", 1);
args = XOBFINISH (&temporary_obstack, char *);
lto_write_data (args, strlen (args) + 1);
- lto_end_section ();
-
obstack_free (&temporary_obstack, NULL);
+
+ const char *collect_as_options = getenv ("COLLECT_AS_OPTIONS");
+ if (collect_as_options)
+ {
+ obstack_init (&temporary_obstack);
+ obstack_grow (&temporary_obstack, collect_as_options,
+ strlen (collect_as_options));
+ obstack_grow (&temporary_obstack, "\0", 1);
+ args = XOBFINISH (&temporary_obstack, char *);
+ lto_write_data (args, strlen (args) + 1);
+ obstack_free (&temporary_obstack, NULL);
+ }
+
+ lto_end_section ();
free (section_name);
}
diff --git a/gcc/lto-wrapper.c b/gcc/lto-wrapper.c
index 9ee1d930364..16c7509cb9f 100644
--- a/gcc/lto-wrapper.c
+++ b/gcc/lto-wrapper.c
@@ -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;
+
default:
if (!(cl_options[foption->opt_index].flags & CL_TARGET))
break;
@@ -624,6 +628,8 @@ append_compiler_options (obstack *argv_obstack, struct cl_decoded_option *opts,
case OPT_Ofast:
case OPT_Og:
case OPT_Os:
+ /* ??? No error checking for Xassembler opts. */
+ case OPT_Xassembler:
break;
default:
diff --git a/gcc/testsuite/gcc.target/arm/pr78353-1.c b/gcc/testsuite/gcc.target/arm/pr78353-1.c
new file mode 100644
index 00000000000..aec0fb0cbfd
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr78353-1.c
@@ -0,0 +1,8 @@
+/* { dg-do link } */
+/* { dg-options "-march=armv7-a -mthumb -O2 -flto -Wa,-mimplicit-it=always" } */
+
+int main(int x)
+{
+ asm("teq %0, #0; addne %0, %0, #1" : "=r" (x));
+ return x;
+}
diff --git a/gcc/testsuite/gcc.target/arm/pr78353-2.c b/gcc/testsuite/gcc.target/arm/pr78353-2.c
new file mode 100644
index 00000000000..18a90e8834e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr78353-2.c
@@ -0,0 +1,9 @@
+/* { dg-do link } */
+/* { dg-options "-march=armv7-a -mthumb -O2 -flto -Wa,-mimplicit-it=always,-mthumb" } */
+
+int main(int x)
+{
+ asm("teq %0, #0; addne %0, %0, #1" : "=r" (x));
+ return x;
+}
+
