Re: [PATCH] RISC-V: Reorder the prefixed extensions which are out of order.

[Nelson Chu <nelson.chu@sifive.com>]

Oops... ummmmm... Fortunately, according to the following link, more
people prefer to relax the architecture string order for both single
and multiple extensions, which means tools should help to reorder all
extensions for -march option.  Although it was an accident, it was
half done, and I pinged this issue again by the way...

https://github.com/riscv-non-isa/riscv-toolchain-conventions/issues/11

Thanks
Nelson

On Wed, Jun 22, 2022 at 8:41 PM Kito Cheng <kito.cheng@sifive.com> wrote:
>
> > I noticed that llvm can reorder the multi-letter extensions, even if
> > they are out of order in the architecture string.
>
> Wait, IIRC that's our downstream change for clang...
>
> > Not really sure if
> > they can also reorder the single letter extensions, and not sure if
> > reordering the single extensions is a good idea.  Anyway, I think
> > RISC-V binuitls should at least help to reorder the multi-letters
> > extensions for now.  Therefore, I re-factor this patch and commit it.
> >
> > Thanks
> > Nelson
> >
> > On Mon, May 31, 2021 at 8:37 PM Nelson Chu <nelson.chu@sifive.com> wrote:
> > >
> > > bfd/
> > >     * elfnn-riscv.c (riscv_merge_arch_attr_info): Updated.
> > >     * elfxx-riscv.c (riscv_add_subset): Replaced riscv_add_subset
> > >     with riscv_add_implicit_subset, and renamed it.
> > >     (riscv_parse_add_subset): Updated.
> > >     (riscv_release_subset_list): Likewise.
> > >     (riscv_parse_prefixed_ext): Help to reorder the prefixed
> > >     extensions if users set the wrong order.
> > >     * elfxx-riscv.h (riscv_subset_t): Removed the unsed tail.
> > > gas/
> > >     * testsuite/gas/riscv/march-fail-order-x-z.d: Removed.
> > >     * testsuite/gas/riscv/march-fail-order-x-z.l: Likewise.
> > >     * testsuite/gas/riscv/march-fail-order-x.d: Likewise.
> > >     * testsuite/gas/riscv/march-fail-order-x.l: Likewise.
> > >     * testsuite/gas/riscv/march-fail-order-z.d: Likewise.
> > >     * testsuite/gas/riscv/march-fail-order-z.l: Likewise.
> > >     * testsuite/gas/riscv/attribute-prefixed-reorder.d: New testcase.
> > >     Reorder the prefixed extensions which are out of order.
> > > ---
> > >  bfd/elfnn-riscv.c                             |  1 -
> > >  bfd/elfxx-riscv.c                             | 70 ++-----------------
> > >  bfd/elfxx-riscv.h                             |  1 -
> > >  .../gas/riscv/attribute-prefixed-reorder.d    |  7 ++
> > >  .../gas/riscv/march-fail-order-x-z.d          |  3 -
> > >  .../gas/riscv/march-fail-order-x-z.l          |  2 -
> > >  gas/testsuite/gas/riscv/march-fail-order-x.d  |  3 -
> > >  gas/testsuite/gas/riscv/march-fail-order-x.l  |  2 -
> > >  gas/testsuite/gas/riscv/march-fail-order-z.d  |  3 -
> > >  gas/testsuite/gas/riscv/march-fail-order-z.l  |  2 -
> > >  10 files changed, 14 insertions(+), 80 deletions(-)
> > >  create mode 100644 gas/testsuite/gas/riscv/attribute-prefixed-reorder.d
> > >  delete mode 100644 gas/testsuite/gas/riscv/march-fail-order-x-z.d
> > >  delete mode 100644 gas/testsuite/gas/riscv/march-fail-order-x-z.l
> > >  delete mode 100644 gas/testsuite/gas/riscv/march-fail-order-x.d
> > >  delete mode 100644 gas/testsuite/gas/riscv/march-fail-order-x.l
> > >  delete mode 100644 gas/testsuite/gas/riscv/march-fail-order-z.d
> > >  delete mode 100644 gas/testsuite/gas/riscv/march-fail-order-z.l
> > >
> > > diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
> > > index eef1e800221..2ff1c6cada4 100644
> > > --- a/bfd/elfnn-riscv.c
> > > +++ b/bfd/elfnn-riscv.c
> > > @@ -3551,7 +3551,6 @@ riscv_merge_arch_attr_info (bfd *ibfd, char *in_arch, char *out_arch)
> > >
> > >    unsigned xlen_in, xlen_out;
> > >    merged_subsets.head = NULL;
> > > -  merged_subsets.tail = NULL;
> > >
> > >    riscv_parse_subset_t rpe_in;
> > >    riscv_parse_subset_t rpe_out;
> > > diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
> > > index 39b69e2b0a5..f7ccac77e81 100644
> > > --- a/bfd/elfxx-riscv.c
> > > +++ b/bfd/elfxx-riscv.c
> > > @@ -1294,37 +1294,14 @@ riscv_lookup_subset (const riscv_subset_list_t *subset_list,
> > >    return false;
> > >  }
> > >
> > > -/* Add extension from ISA string to the last of the subset list.  */
> > > +/* Add the extension to the subset list.  Search the
> > > +   list first, and then find the right place to add.  */
> > >
> > >  void
> > >  riscv_add_subset (riscv_subset_list_t *subset_list,
> > >                   const char *subset,
> > >                   int major,
> > >                   int minor)
> > > -{
> > > -  riscv_subset_t *s = xmalloc (sizeof *s);
> > > -
> > > -  if (subset_list->head == NULL)
> > > -    subset_list->head = s;
> > > -
> > > -  s->name = xstrdup (subset);
> > > -  s->major_version = major;
> > > -  s->minor_version = minor;
> > > -  s->next = NULL;
> > > -
> > > -  if (subset_list->tail != NULL)
> > > -    subset_list->tail->next = s;
> > > -  subset_list->tail = s;
> > > -}
> > > -
> > > -/* Add the implicit extension to the subset list.  Search the
> > > -   list first, and then find the right place to add.  */
> > > -
> > > -static void
> > > -riscv_add_implicit_subset (riscv_subset_list_t *subset_list,
> > > -                          const char *subset,
> > > -                          int major,
> > > -                          int minor)
> > >  {
> > >    riscv_subset_t *current, *new;
> > >
> > > @@ -1349,12 +1326,7 @@ riscv_add_implicit_subset (riscv_subset_list_t *subset_list,
> > >      }
> > >  }
> > >
> > > -/* We have to add all extensions from ISA string first, and then start to
> > > -   add their implicit extensions.  The extensions from ISA string must be
> > > -   set in order, so we can add them to the last of the subset list
> > > -   directly, without searching.
> > > -
> > > -   Find the default versions for the extension before adding them to
> > > +/* Find the default versions for the extension before adding them to
> > >     the subset list, if their versions are RISCV_UNKNOWN_VERSION.
> > >     Afterwards, report errors if we can not find their default versions.  */
> > >
> > > @@ -1389,12 +1361,8 @@ riscv_parse_add_subset (riscv_parse_subset_t *rps,
> > >        return;
> > >      }
> > >
> > > -  if (!implicit)
> > > -    riscv_add_subset (rps->subset_list, subset,
> > > -                     major_version, minor_version);
> > > -  else
> > > -    riscv_add_implicit_subset (rps->subset_list, subset,
> > > -                              major_version, minor_version);
> > > +  riscv_add_subset (rps->subset_list, subset,
> > > +                   major_version, minor_version);
> > >  }
> > >
> > >  /* Release subset list.  */
> > > @@ -1409,8 +1377,6 @@ riscv_release_subset_list (riscv_subset_list_t *subset_list)
> > >        free (subset_list->head);
> > >        subset_list->head = next;
> > >      }
> > > -
> > > -  subset_list->tail = NULL;
> > >  }
> > >
> > >  /* Parsing extension version.
> > > @@ -1636,7 +1602,6 @@ riscv_parse_prefixed_ext (riscv_parse_subset_t *rps,
> > >  {
> > >    int major_version;
> > >    int minor_version;
> > > -  const char *last_name;
> > >    enum riscv_prefix_ext_class class;
> > >
> > >    while (*p)
> > > @@ -1691,28 +1656,6 @@ riscv_parse_prefixed_ext (riscv_parse_subset_t *rps,
> > >           return NULL;
> > >         }
> > >
> > > -      /* Check that the extension isn't duplicate.  */
> > > -      last_name = rps->subset_list->tail->name;
> > > -      if (!strcasecmp (last_name, subset))
> > > -       {
> > > -         rps->error_handler
> > > -           (_("-march=%s: duplicate prefixed ISA extension `%s'"),
> > > -            march, subset);
> > > -         free (subset);
> > > -         return NULL;
> > > -       }
> > > -
> > > -      /* Check that the extension is in expected order.  */
> > > -      if (riscv_compare_subsets (last_name, subset) > 0)
> > > -       {
> > > -         rps->error_handler
> > > -           (_("-march=%s: prefixed ISA extension `%s' is not in expected "
> > > -              "order.  It must come before `%s'"),
> > > -            march, subset, last_name);
> > > -         free (subset);
> > > -         return NULL;
> > > -       }
> > > -
> > >        riscv_parse_add_subset (rps, subset,
> > >                               major_version,
> > >                               minor_version, false);
> > > @@ -1811,7 +1754,8 @@ riscv_parse_subset (riscv_parse_subset_t *rps,
> > >    if (p == NULL)
> > >      return false;
> > >
> > > -  /* Parse the different classes of extensions in the specified order.  */
> > > +  /* Parse the prefixed extensions, we will help to reorder them to
> > > +     the correct order.  */
> > >    while (*p != '\0')
> > >      {
> > >        p = riscv_parse_prefixed_ext (rps, arch, p);
> > > diff --git a/bfd/elfxx-riscv.h b/bfd/elfxx-riscv.h
> > > index 6a2501b7be8..c1885158a9f 100644
> > > --- a/bfd/elfxx-riscv.h
> > > +++ b/bfd/elfxx-riscv.h
> > > @@ -49,7 +49,6 @@ typedef struct riscv_subset_t riscv_subset_t;
> > >  typedef struct
> > >  {
> > >    riscv_subset_t *head;
> > > -  riscv_subset_t *tail;
> > >  } riscv_subset_list_t;
> > >
> > >  extern void
> > > diff --git a/gas/testsuite/gas/riscv/attribute-prefixed-reorder.d b/gas/testsuite/gas/riscv/attribute-prefixed-reorder.d
> > > new file mode 100644
> > > index 00000000000..a46a68cd985
> > > --- /dev/null
> > > +++ b/gas/testsuite/gas/riscv/attribute-prefixed-reorder.d
> > > @@ -0,0 +1,7 @@
> > > +#as: -misa-spec=20191213 -march-attr -march=rv64gc_zbc_zba_zifencei_xbargle2p0_zbb_zicsr_xargle2p0
> > > +#readelf: -A
> > > +#source: empty.s
> > > +
> > > +Attribute Section: riscv
> > > +File Attributes
> > > +  Tag_RISCV_arch: "rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0_zifencei2p0_zba0p93_zbb0p93_zbc0p93_xargle2p0_xbargle2p0"
> > > diff --git a/gas/testsuite/gas/riscv/march-fail-order-x-z.d b/gas/testsuite/gas/riscv/march-fail-order-x-z.d
> > > deleted file mode 100644
> > > index 7245e68e0ea..00000000000
> > > --- a/gas/testsuite/gas/riscv/march-fail-order-x-z.d
> > > +++ /dev/null
> > > @@ -1,3 +0,0 @@
> > > -#as: -march=rv32i_xargle2p0_zicsr2p0
> > > -#source: empty.s
> > > -#error_output: march-fail-order-x-z.l
> > > diff --git a/gas/testsuite/gas/riscv/march-fail-order-x-z.l b/gas/testsuite/gas/riscv/march-fail-order-x-z.l
> > > deleted file mode 100644
> > > index 53ea8201187..00000000000
> > > --- a/gas/testsuite/gas/riscv/march-fail-order-x-z.l
> > > +++ /dev/null
> > > @@ -1,2 +0,0 @@
> > > -.*Assembler messages:
> > > -.*Error: .*prefixed ISA extension `zicsr' is not in expected order.  It must come before `xargle'
> > > diff --git a/gas/testsuite/gas/riscv/march-fail-order-x.d b/gas/testsuite/gas/riscv/march-fail-order-x.d
> > > deleted file mode 100644
> > > index 72a821ef8e6..00000000000
> > > --- a/gas/testsuite/gas/riscv/march-fail-order-x.d
> > > +++ /dev/null
> > > @@ -1,3 +0,0 @@
> > > -#as: -march=rv32i_xbargle2p0_xargle2p0
> > > -#source: empty.s
> > > -#error_output: march-fail-order-x.l
> > > diff --git a/gas/testsuite/gas/riscv/march-fail-order-x.l b/gas/testsuite/gas/riscv/march-fail-order-x.l
> > > deleted file mode 100644
> > > index cfb118528df..00000000000
> > > --- a/gas/testsuite/gas/riscv/march-fail-order-x.l
> > > +++ /dev/null
> > > @@ -1,2 +0,0 @@
> > > -.*Assembler messages:
> > > -.*Error: .*prefixed ISA extension `xargle' is not in expected order.  It must come before `xbargle'
> > > diff --git a/gas/testsuite/gas/riscv/march-fail-order-z.d b/gas/testsuite/gas/riscv/march-fail-order-z.d
> > > deleted file mode 100644
> > > index dd076c6d35a..00000000000
> > > --- a/gas/testsuite/gas/riscv/march-fail-order-z.d
> > > +++ /dev/null
> > > @@ -1,3 +0,0 @@
> > > -#as: -march=rv32i_zifencei2p0_zicsr2p0
> > > -#source: empty.s
> > > -#error_output: march-fail-order-z.l
> > > diff --git a/gas/testsuite/gas/riscv/march-fail-order-z.l b/gas/testsuite/gas/riscv/march-fail-order-z.l
> > > deleted file mode 100644
> > > index 468c412051f..00000000000
> > > --- a/gas/testsuite/gas/riscv/march-fail-order-z.l
> > > +++ /dev/null
> > > @@ -1,2 +0,0 @@
> > > -.*Assembler messages:
> > > -.*Error: .*prefixed ISA extension `zicsr' is not in expected order.  It must come before `zifencei'
> > > --
> > > 2.30.2
> > >