On Mon, Jun 17, 2024 at 5:51 PM Kito Cheng <kito.ch...@gmail.com> wrote:
> Maybe just add 'a' to riscv_combine_info and other logic to keep the
> same (e.g. keep the logic for skip_zaamo_zalrsc)?
I did consider unconditionally upgrading zaamo/zalrsc to ‘a’ (I think
that’s what you’re suggesting w/ riscv_combine_info).
That could cause issues if users are trying to compile for a zalrsc-only
chip with an old version of binutils. If we upgrade zalrsc -> ‘a’ for both
cc1 and binutils then cc1 will emit amo ops instead of their lr/sc
equivalent.
GCC would end up emitting insns that are illegal for the user-provided
-march string.
Patrick
> On Tue, Jun 18, 2024 at 8:03 AM Patrick O'Neill <patr...@rivosinc.com>
> wrote:
> >
> > Binutils 2.42 and before don't support Zaamo/Zalrsc. Promote
> Zaamo/Zalrsc to
> > 'a' in the -march string when assembling.
> >
> > This change respects Zaamo/Zalrsc when generating code.
> >
> > Testcases that check for the default isa string will fail with the old
> binutils
> > since zaamo/zalrsc aren't emitted anymore. All other Zaamo/Zalrsc
> testcases
> > pass.
> >
> > gcc/ChangeLog:
> >
> > * common/config/riscv/riscv-common.cc
> > (riscv_subset_list::to_string): Add toggle to promote
> Zaamo/Zalrsc
> > extensions to 'a'.
> > (riscv_arch_str): Ditto.
> > (riscv_expand_arch): Ditto.
> > (riscv_expand_arch_from_cpu): Ditto.
> > (riscv_expand_arch_upgrade_exts): New function. Wrapper around
> > riscv_expand_arch to preserve the function signature.
> > (riscv_expand_arch_no_upgrade_exts): Ditto
> > (riscv_expand_arch_from_cpu_upgrade_exts): New function. Wrapper
> around
> > riscv_expand_arch_from_cpu to preserve the function signature.
> > (riscv_expand_arch_from_cpu_no_upgrade_exts): Ditto.
> > * config/riscv/riscv-protos.h (riscv_arch_str): Add toggle to
> function
> > prototype.
> > * config/riscv/riscv-subset.h: Ditto.
> > * config/riscv/riscv-target-attr.cc (riscv_process_target_attr):
> > * config/riscv/riscv.cc (riscv_emit_attribute):
> > (riscv_declare_function_name):
> > * config/riscv/riscv.h (riscv_expand_arch): Remove.
> > (riscv_expand_arch_from_cpu): Ditto.
> > (riscv_expand_arch_upgrade_exts): Add toggle wrapper functions.
> > (riscv_expand_arch_no_upgrade_exts): Ditto.
> > (riscv_expand_arch_from_cpu_upgrade_exts): Ditto.
> > (riscv_expand_arch_from_cpu_no_upgrade_exts): Ditto.
> > (EXTRA_SPEC_FUNCTIONS): Ditto.
> > (OPTION_DEFAULT_SPECS): Use non-upgraded march string when
> invoking the
> > compiler.
> > (ASM_SPEC): Use upgraded march string when invoking the
> assembler.
> >
> > Signed-off-by: Patrick O'Neill <patr...@rivosinc.com>
> > ---
> > v3 ChangeLog:
> > Rebased on non-promoting patch.
> > Wrap all Zaamo/Zalrsc upgrade code in #ifndef to prevent compiler
> > warnings about unused/potentially undefined variables.
> > Silence unused parameter warning with a voidcast.
> > ---
> > RFC since I'm not sure if this upgrade behavior is more trouble than
> > it's worth - this is a pretty invasive change. Happy to iterate further
> > or just drop these changes.
> > ---
> > gcc/common/config/riscv/riscv-common.cc | 111 +++++++++++++++++++++---
> > gcc/config/riscv/riscv-protos.h | 3 +-
> > gcc/config/riscv/riscv-subset.h | 2 +-
> > gcc/config/riscv/riscv-target-attr.cc | 4 +-
> > gcc/config/riscv/riscv.cc | 7 +-
> > gcc/config/riscv/riscv.h | 46 ++++++----
> > 6 files changed, 137 insertions(+), 36 deletions(-)
> >
> > diff --git a/gcc/common/config/riscv/riscv-common.cc
> b/gcc/common/config/riscv/riscv-common.cc
> > index 1dc1d9904c7..05c26f73b73 100644
> > --- a/gcc/common/config/riscv/riscv-common.cc
> > +++ b/gcc/common/config/riscv/riscv-common.cc
> > @@ -907,7 +907,7 @@ riscv_subset_list::add (const char *subset, bool
> implied_p)
> > VERSION_P to determine append version info or not. */
> >
> > std::string
> > -riscv_subset_list::to_string (bool version_p) const
> > +riscv_subset_list::to_string (bool version_p, bool upgrade_exts) const
> > {
> > std::ostringstream oss;
> > oss << "rv" << m_xlen;
> > @@ -916,10 +916,17 @@ riscv_subset_list::to_string (bool version_p) const
> > riscv_subset_t *subset;
> >
> > bool skip_zifencei = false;
> > - bool skip_zaamo_zalrsc = false;
> > bool skip_zicsr = false;
> > bool i2p0 = false;
> >
> > +#ifndef HAVE_AS_MARCH_ZAAMO_ZALRSC
> > + bool upgrade_zaamo_zalrsc = false;
> > + bool has_a_ext = false;
> > + bool insert_a_ext = false;
> > + bool inserted_a_ext = false;
> > + riscv_subset_t *a_subset;
> > +#endif
> > +
> > /* For RISC-V ISA version 2.2 or earlier version, zicsr and zifencei
> is
> > included in the base ISA. */
> > if (riscv_isa_spec == ISA_SPEC_CLASS_2P2)
> > @@ -945,8 +952,33 @@ riscv_subset_list::to_string (bool version_p) const
> > skip_zifencei = true;
> > #endif
> > #ifndef HAVE_AS_MARCH_ZAAMO_ZALRSC
> > - /* Skip since binutils 2.42 and earlier don't recognize
> zaamo/zalrsc. */
> > - skip_zaamo_zalrsc = true;
> > + /* Upgrade Zaamo/Zalrsc extensions to 'a' since binutils 2.42 and
> earlier
> > + don't recognize zaamo/zalrsc. */
> > + upgrade_zaamo_zalrsc = upgrade_exts;
> > + if (upgrade_zaamo_zalrsc)
> > + {
> > + for (subset = m_head; subset != NULL; subset = subset->next)
> > + {
> > + if (subset->name == "a")
> > + has_a_ext = true;
> > + if (subset->name == "zaamo" || subset->name == "zalrsc")
> > + insert_a_ext = true;
> > + }
> > + if (insert_a_ext && !has_a_ext)
> > + {
> > + unsigned int major_version = 0, minor_version = 0;
> > + get_default_version ("a", &major_version, &minor_version);
> > + a_subset = new riscv_subset_t ();
> > + a_subset->name = "a";
> > + a_subset->implied_p = false;
> > + a_subset->major_version = major_version;
> > + a_subset->minor_version = minor_version;
> > + }
> > + }
> > +#else
> > + /* Silence unused parameter warning when HAVE_AS_MARCH_ZAAMO_ZALRSC is
> > + set. */
> > + (void) upgrade_exts;
> > #endif
> >
> > for (subset = m_head; subset != NULL; subset = subset->next)
> > @@ -959,12 +991,29 @@ riscv_subset_list::to_string (bool version_p) const
> > subset->name == "zicsr")
> > continue;
> >
> > - if (skip_zaamo_zalrsc && subset->name == "zaamo")
> > +#ifndef HAVE_AS_MARCH_ZAAMO_ZALRSC
> > + if (upgrade_zaamo_zalrsc && subset->name == "zaamo")
> > continue;
> >
> > - if (skip_zaamo_zalrsc && subset->name == "zalrsc")
> > + if (upgrade_zaamo_zalrsc && subset->name == "zalrsc")
> > continue;
> >
> > + if (upgrade_zaamo_zalrsc && insert_a_ext && !has_a_ext &&
> !inserted_a_ext)
> > + {
> > + gcc_assert (a_subset);
> > + /* Insert `a` extension in cannonical order. */
> > + if (subset_cmp (a_subset->name, subset->name) > 0)
> > + {
> > + oss << a_subset->name;
> > + if (version_p)
> > + oss << a_subset->major_version
> > + << 'p'
> > + << a_subset->minor_version;
> > + inserted_a_ext = true;
> > + }
> > + }
> > +#endif
> > +
> > /* For !version_p, we only separate extension with underline for
> > multi-letter extension. */
> > if (!first &&
> > @@ -984,6 +1033,14 @@ riscv_subset_list::to_string (bool version_p) const
> > << subset->minor_version;
> > }
> >
> > +#ifndef HAVE_AS_MARCH_ZAAMO_ZALRSC
> > + if (upgrade_zaamo_zalrsc && insert_a_ext && !has_a_ext)
> > + {
> > + gcc_assert (inserted_a_ext);
> > + free (a_subset);
> > + }
> > +#endif
> > +
> > return oss.str ();
> > }
> >
> > @@ -1598,10 +1655,10 @@ riscv_subset_list::finalize ()
> > /* Return the current arch string. */
> >
> > std::string
> > -riscv_arch_str (bool version_p)
> > +riscv_arch_str (bool version_p, bool upgrade_exts)
> > {
> > if (current_subset_list)
> > - return current_subset_list->to_string (version_p);
> > + return current_subset_list->to_string (version_p, upgrade_exts);
> > else
> > return std::string();
> > }
> > @@ -1907,18 +1964,33 @@ riscv_handle_option (struct gcc_options *opts,
> >
> > const char *
> > riscv_expand_arch (int argc ATTRIBUTE_UNUSED,
> > - const char **argv)
> > + const char **argv,
> > + bool upgrade_exts)
> > {
> > gcc_assert (argc == 1);
> > location_t loc = UNKNOWN_LOCATION;
> > riscv_parse_arch_string (argv[0], NULL, loc);
> > - const std::string arch = riscv_arch_str (false);
> > + const std::string arch = riscv_arch_str (/*version_p*/ false,
> upgrade_exts);
> > if (arch.length())
> > return xasprintf ("-march=%s", arch.c_str());
> > else
> > return "";
> > }
> >
> > +const char *
> > +riscv_expand_arch_upgrade_exts (int argc ATTRIBUTE_UNUSED,
> > + const char **argv)
> > +{
> > + return riscv_expand_arch (argc, argv, /*upgrade_exts*/ true);
> > +}
> > +
> > +const char *
> > +riscv_expand_arch_no_upgrade_exts (int argc ATTRIBUTE_UNUSED,
> > + const char **argv)
> > +{
> > + return riscv_expand_arch (argc, argv, /*upgrade_exts*/ false);
> > +}
> > +
> > /* Expand default -mtune option from -mcpu option, use default
> --with-tune value
> > if -mcpu don't have valid value. */
> >
> > @@ -1938,7 +2010,8 @@ riscv_default_mtune (int argc, const char **argv)
> >
> > const char *
> > riscv_expand_arch_from_cpu (int argc ATTRIBUTE_UNUSED,
> > - const char **argv)
> > + const char **argv,
> > + bool upgrade_exts)
> > {
> > gcc_assert (argc > 0 && argc <= 2);
> > const char *default_arch_str = NULL;
> > @@ -1961,10 +2034,24 @@ riscv_expand_arch_from_cpu (int argc
> ATTRIBUTE_UNUSED,
> > location_t loc = UNKNOWN_LOCATION;
> >
> > riscv_parse_arch_string (arch_str, NULL, loc);
> > - const std::string arch = riscv_arch_str (false);
> > + const std::string arch = riscv_arch_str (/*version_p*/ false,
> upgrade_exts);
> > return xasprintf ("-march=%s", arch.c_str());
> > }
> >
> > +const char *
> > +riscv_expand_arch_from_cpu_upgrade_exts (int argc ATTRIBUTE_UNUSED,
> > + const char **argv)
> > +{
> > + return riscv_expand_arch_from_cpu (argc, argv, /*upgrade_exts*/ true);
> > +}
> > +
> > +const char *
> > +riscv_expand_arch_from_cpu_no_upgrade_exts (int argc ATTRIBUTE_UNUSED,
> > + const char **argv)
> > +{
> > + return riscv_expand_arch_from_cpu (argc, argv, /*upgrade_exts*/
> false);
> > +}
> > +
> > /* Report error if not found suitable multilib. */
> > const char *
> > riscv_multi_lib_check (int argc ATTRIBUTE_UNUSED,
> > diff --git a/gcc/config/riscv/riscv-protos.h
> b/gcc/config/riscv/riscv-protos.h
> > index d6473d0cd85..06b33c9f330 100644
> > --- a/gcc/config/riscv/riscv-protos.h
> > +++ b/gcc/config/riscv/riscv-protos.h
> > @@ -183,7 +183,8 @@ extern tree riscv_builtin_decl (unsigned int, bool);
> > extern void riscv_init_builtins (void);
> >
> > /* Routines implemented in riscv-common.cc. */
> > -extern std::string riscv_arch_str (bool version_p = true);
> > +extern std::string riscv_arch_str (bool version_p = true,
> > + bool upgrade_exts = false);
> > extern void riscv_parse_arch_string (const char *, struct gcc_options
> *, location_t);
> >
> > extern bool riscv_hard_regno_rename_ok (unsigned, unsigned);
> > diff --git a/gcc/config/riscv/riscv-subset.h
> b/gcc/config/riscv/riscv-subset.h
> > index fe7f54d8bc5..8384aab63cb 100644
> > --- a/gcc/config/riscv/riscv-subset.h
> > +++ b/gcc/config/riscv/riscv-subset.h
> > @@ -90,7 +90,7 @@ public:
> > int major_version = RISCV_DONT_CARE_VERSION,
> > int minor_version = RISCV_DONT_CARE_VERSION)
> const;
> >
> > - std::string to_string (bool) const;
> > + std::string to_string (bool, bool) const;
> >
> > unsigned xlen () const {return m_xlen;};
> >
> > diff --git a/gcc/config/riscv/riscv-target-attr.cc
> b/gcc/config/riscv/riscv-target-attr.cc
> > index 19eb7b06d54..42c2b439e66 100644
> > --- a/gcc/config/riscv/riscv-target-attr.cc
> > +++ b/gcc/config/riscv/riscv-target-attr.cc
> > @@ -367,7 +367,9 @@ riscv_process_target_attr (tree fndecl, tree args,
> location_t loc,
> > /* Add the string of the target attribute to the fndecl hash table.
> */
> > riscv_subset_list *subset_list = attr_parser.get_riscv_subset_list ();
> > if (subset_list)
> > - riscv_func_target_put (fndecl, subset_list->to_string (true));
> > + riscv_func_target_put (fndecl,
> > + subset_list->to_string (/*version_p*/ true,
> > + /*upgrade_exts*/
> true));
> >
> > return true;
> > }
> > diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
> > index c17141d909a..09943389986 100644
> > --- a/gcc/config/riscv/riscv.cc
> > +++ b/gcc/config/riscv/riscv.cc
> > @@ -9425,8 +9425,10 @@ riscv_sched_adjust_cost (rtx_insn *, int,
> rtx_insn *insn, int cost,
> > static void
> > riscv_emit_attribute ()
> > {
> > + /* Upgrade extensions if necessary for the assember to understand
> > + Eg. Zalrsc -> a. */
> > fprintf (asm_out_file, "\t.attribute arch, \"%s\"\n",
> > - riscv_arch_str ().c_str ());
> > + riscv_arch_str (/*version_p*/ true, /*upgrade_exts*/
> true).c_str ());
> >
> > fprintf (asm_out_file, "\t.attribute unaligned_access, %d\n",
> > TARGET_STRICT_ALIGN ? 0 : 1);
> > @@ -9468,7 +9470,8 @@ riscv_declare_function_name (FILE *stream, const
> char *name, tree fndecl)
> > std::string *target_name = riscv_func_target_get (fndecl);
> > std::string isa = target_name != NULL
> > ? *target_name
> > - : riscv_cmdline_subset_list ()->to_string (true);
> > + : riscv_cmdline_subset_list ()->to_string (/*version_p*/ true,
> > + /*upgrade_exts*/
> true);
> > fprintf (stream, "\t.option arch, %s\n", isa.c_str ());
> > riscv_func_target_remove_and_destory (fndecl);
> >
> > diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
> > index 57910eecd3e..55d0a842bf2 100644
> > --- a/gcc/config/riscv/riscv.h
> > +++ b/gcc/config/riscv/riscv.h
> > @@ -46,17 +46,24 @@ along with GCC; see the file COPYING3. If not see
> > #define RISCV_TUNE_STRING_DEFAULT "rocket"
> > #endif
> >
> > -extern const char *riscv_expand_arch (int argc, const char **argv);
> > -extern const char *riscv_expand_arch_from_cpu (int argc, const char
> **argv);
> > +extern const char *riscv_expand_arch_upgrade_exts (int argc, const char
> **argv);
> > +extern const char *riscv_expand_arch_no_upgrade_exts (int argc,
> > + const char **argv);
> > +extern const char *riscv_expand_arch_from_cpu_upgrade_exts (int argc,
> > + const char
> **argv);
> > +extern const char *riscv_expand_arch_from_cpu_no_upgrade_exts (int argc,
> > + const
> char **argv);
> > extern const char *riscv_default_mtune (int argc, const char **argv);
> > extern const char *riscv_multi_lib_check (int argc, const char **argv);
> > extern const char *riscv_arch_help (int argc, const char **argv);
> >
> > -# define EXTRA_SPEC_FUNCTIONS \
> > - { "riscv_expand_arch", riscv_expand_arch }, \
> > - { "riscv_expand_arch_from_cpu", riscv_expand_arch_from_cpu },
> \
> > - { "riscv_default_mtune", riscv_default_mtune }, \
> > - { "riscv_multi_lib_check", riscv_multi_lib_check }, \
> > +# define EXTRA_SPEC_FUNCTIONS
> \
> > + { "riscv_expand_arch_u", riscv_expand_arch_upgrade_exts },
> \
> > + { "riscv_expand_arch_nu", riscv_expand_arch_no_upgrade_exts },
> \
> > + { "riscv_expand_arch_from_cpu_nu",
> riscv_expand_arch_from_cpu_no_upgrade_exts }, \
> > + { "riscv_expand_arch_from_cpu_u",
> riscv_expand_arch_from_cpu_upgrade_exts }, \
> > + { "riscv_default_mtune", riscv_default_mtune },
> \
> > + { "riscv_multi_lib_check", riscv_multi_lib_check },
> \
> > { "riscv_arch_help", riscv_arch_help },
> >
> > /* Support for a compile-time default CPU, et cetera. The rules are:
> > @@ -68,15 +75,15 @@ extern const char *riscv_arch_help (int argc, const
> char **argv);
> >
> > But using default -march/-mtune value if -mcpu don't have valid
> option. */
> > #define OPTION_DEFAULT_SPECS \
> > - {"tune", "%{!mtune=*:" \
> > - " %{!mcpu=*:-mtune=%(VALUE)}" \
> > - " %{mcpu=*:-mtune=%:riscv_default_mtune(%* %(VALUE))}}" }, \
> > - {"arch", "%{!march=*:" \
> > - " %{!mcpu=*:-march=%(VALUE)}" \
> > - " %{mcpu=*:%:riscv_expand_arch_from_cpu(%* %(VALUE))}}" }, \
> > - {"abi", "%{!mabi=*:-mabi=%(VALUE)}" }, \
> > - {"isa_spec", "%{!misa-spec=*:-misa-spec=%(VALUE)}" },
> \
> > - {"tls", "%{!mtls-dialect=*:-mtls-dialect=%(VALUE)}"}, \
> > + {"tune", "%{!mtune=*:"
> \
> > + " %{!mcpu=*:-mtune=%(VALUE)}"
> \
> > + " %{mcpu=*:-mtune=%:riscv_default_mtune(%* %(VALUE))}}" },
> \
> > + {"arch", "%{!march=*:"
> \
> > + " %{!mcpu=*:-march=%(VALUE)}"
> \
> > + " %{mcpu=*:%:riscv_expand_arch_from_cpu_nu(%* %(VALUE))}}"
> }, \
> > + {"abi", "%{!mabi=*:-mabi=%(VALUE)}" },
> \
> > + {"isa_spec", "%{!misa-spec=*:-misa-spec=%(VALUE)}" },
> \
> > + {"tls", "%{!mtls-dialect=*:-mtls-dialect=%(VALUE)}"},
> \
> >
> > #ifdef IN_LIBGCC2
> > #undef TARGET_64BIT
> > @@ -103,7 +110,8 @@ extern const char *riscv_arch_help (int argc, const
> char **argv);
> > #define ASM_SPEC "\
> > %(subtarget_asm_debugging_spec) \
> > %{" FPIE_OR_FPIC_SPEC ":-fpic} \
> > -%{march=*} \
> > +%{march=*:%:riscv_expand_arch_u(%*)} \
> > +%{!march=*:%{mcpu=*:%:riscv_expand_arch_from_cpu_u(%*)}} \
> > %{mabi=*} \
> > %{mno-relax} \
> > %{mbig-endian} \
> > @@ -116,8 +124,8 @@ ASM_MISA_SPEC
> > "%{march=help:%:riscv_arch_help()} " \
> > "%{print-supported-extensions:%:riscv_arch_help()} " \
> > "%{-print-supported-extensions:%:riscv_arch_help()} " \
> > -"%{march=*:%:riscv_expand_arch(%*)} " \
> > -"%{!march=*:%{mcpu=*:%:riscv_expand_arch_from_cpu(%*)}} "
> > +"%{march=*:%:riscv_expand_arch_nu(%*)} " \
> > +"%{!march=*:%{mcpu=*:%:riscv_expand_arch_from_cpu_nu(%*)}} "
> >
> > #define TARGET_DEFAULT_CMODEL CM_MEDLOW
> >
> > --
> > 2.34.1
> >
>
