On 09/03/2021 15:41, Alex Coplan via Gcc-patches wrote:
> Hi all,
>
> Here is a v2 patch which provides a more obviously fake answer to
> TARGET_BUILTIN_DECL: this can hopefully go in for GCC 11. For GCC 12, it
> seems that we should consider removing the target hook.
>
> Original patch:
> https://gcc.gnu.org/pipermail/gcc-patches/2021-March/566405.html
Ping. OK for trunk?
>
> ---
>
> As discussed in the PR, we currently have two different numbering
> schemes for SVE builtins: one for C, and one for C++. This is
> problematic for LTO, where we end up getting confused about which
> intrinsic we're talking about. This patch inserts placeholders into the
> registered_functions vector to ensure that there is a consistent
> numbering scheme for both C and C++.
>
> This patch uses integer_zero_node as a placeholder node instead of
> building a function decl. This is safe because the node is only returned
> by the TARGET_BUILTIN_DECL hook, which (on AArch64) is only used for
> validation when builtin decls are streamed into lto1.
>
> Bootstrapped and regtested on aarch64-linux-gnu, OK for trunk?
>
> Thanks,
> Alex
>
> gcc/ChangeLog:
>
> PR target/99216
> * config/aarch64/aarch64-sve-builtins.cc
> (function_builder::add_function): Add placeholder_p argument, use
> placeholder decls if this is set.
> (function_builder::add_unique_function): Instead of conditionally adding
> direct overloads, unconditionally add either a direct overload or a
> placeholder.
> (function_builder::add_overloaded_function): Set placeholder_p if we're
> using C++ overloads. Use the obstack for string storage instead
> of relying on the tree nodes.
> (function_builder::add_overloaded_functions): Don't return early for
> m_direct_overloads: we need to add placeholders.
> * config/aarch64/aarch64-sve-builtins.h
> (function_builder::add_function): Add placeholder_p argument.
>
> gcc/testsuite/ChangeLog:
>
> PR target/99216
> * g++.target/aarch64/sve/pr99216.C: New test.
> diff --git a/gcc/config/aarch64/aarch64-sve-builtins.cc
> b/gcc/config/aarch64/aarch64-sve-builtins.cc
> index 25612d2ea52..f44f81f1375 100644
> --- a/gcc/config/aarch64/aarch64-sve-builtins.cc
> +++ b/gcc/config/aarch64/aarch64-sve-builtins.cc
> @@ -999,12 +999,29 @@ registered_function &
> function_builder::add_function (const function_instance &instance,
> const char *name, tree fntype, tree attrs,
> uint64_t required_extensions,
> - bool overloaded_p)
> + bool overloaded_p,
> + bool placeholder_p)
> {
> unsigned int code = vec_safe_length (registered_functions);
> code = (code << AARCH64_BUILTIN_SHIFT) | AARCH64_BUILTIN_SVE;
> - tree decl = simulate_builtin_function_decl (input_location, name, fntype,
> - code, NULL, attrs);
> +
> + /* We need to be able to generate placeholders to enusre that we have a
> + consistent numbering scheme for function codes between the C and C++
> + frontends, so that everything ties up in LTO.
> +
> + Currently, tree-streamer-in.c:unpack_ts_function_decl_value_fields
> + validates that tree nodes returned by TARGET_BUILTIN_DECL are non-NULL
> and
> + some node other than error_mark_node. This is a holdover from when
> builtin
> + decls were streamed by code rather than by value.
> +
> + Ultimately, we should be able to remove this validation of BUILT_IN_MD
> + nodes and remove the target hook. For now, however, we need to appease
> the
> + validation and return a non-NULL, non-error_mark_node node, so we
> + arbitrarily choose integer_zero_node. */
> + tree decl = placeholder_p
> + ? integer_zero_node
> + : simulate_builtin_function_decl (input_location, name, fntype,
> + code, NULL, attrs);
>
> registered_function &rfn = *ggc_alloc <registered_function> ();
> rfn.instance = instance;
> @@ -1036,7 +1053,7 @@ function_builder::add_unique_function (const
> function_instance &instance,
> argument_types.address ());
> tree attrs = get_attributes (instance);
> registered_function &rfn = add_function (instance, name, fntype, attrs,
> - required_extensions, false);
> + required_extensions, false, false);
>
> /* Enter the function into the hash table. */
> hashval_t hash = instance.hash ();
> @@ -1047,16 +1064,14 @@ function_builder::add_unique_function (const
> function_instance &instance,
>
> /* Also add the function under its overloaded alias, if we want
> a separate decl for each instance of an overloaded function. */
> - if (m_direct_overloads || force_direct_overloads)
> + char *overload_name = get_name (instance, true);
> + if (strcmp (name, overload_name) != 0)
> {
> - char *overload_name = get_name (instance, true);
> - if (strcmp (name, overload_name) != 0)
> - {
> - /* Attribute lists shouldn't be shared. */
> - tree attrs = get_attributes (instance);
> - add_function (instance, overload_name, fntype, attrs,
> - required_extensions, false);
> - }
> + /* Attribute lists shouldn't be shared. */
> + tree attrs = get_attributes (instance);
> + bool placeholder_p = !(m_direct_overloads || force_direct_overloads);
> + add_function (instance, overload_name, fntype, attrs,
> + required_extensions, false, placeholder_p);
> }
>
> obstack_free (&m_string_obstack, name);
> @@ -1077,18 +1092,19 @@ function_builder::add_overloaded_function (const
> function_instance &instance,
> {
> char *name = get_name (instance, true);
> if (registered_function **map_value = m_overload_names.get (name))
> - gcc_assert ((*map_value)->instance == instance
> - && ((*map_value)->required_extensions
> - & ~required_extensions) == 0);
> + {
> + gcc_assert ((*map_value)->instance == instance
> + && ((*map_value)->required_extensions
> + & ~required_extensions) == 0);
> + obstack_free (&m_string_obstack, name);
> + }
> else
> {
> registered_function &rfn
> = add_function (instance, name, m_overload_type, NULL_TREE,
> - required_extensions, true);
> - const char *permanent_name = IDENTIFIER_POINTER (DECL_NAME (rfn.decl));
> - m_overload_names.put (permanent_name, &rfn);
> + required_extensions, true, m_direct_overloads);
> + m_overload_names.put (name, &rfn);
> }
> - obstack_free (&m_string_obstack, name);
> }
>
> /* If we are using manual overload resolution, add one function decl
> @@ -1098,9 +1114,6 @@ void
> function_builder::add_overloaded_functions (const function_group_info &group,
> mode_suffix_index mode)
> {
> - if (m_direct_overloads)
> - return;
> -
> unsigned int explicit_type0 = (*group.shape)->explicit_type_suffix_p (0);
> unsigned int explicit_type1 = (*group.shape)->explicit_type_suffix_p (1);
> for (unsigned int pi = 0; group.preds[pi] != NUM_PREDS; ++pi)
> diff --git a/gcc/config/aarch64/aarch64-sve-builtins.h
> b/gcc/config/aarch64/aarch64-sve-builtins.h
> index 620e18841b2..b701f90ac1a 100644
> --- a/gcc/config/aarch64/aarch64-sve-builtins.h
> +++ b/gcc/config/aarch64/aarch64-sve-builtins.h
> @@ -337,7 +337,8 @@ private:
> tree get_attributes (const function_instance &);
>
> registered_function &add_function (const function_instance &,
> - const char *, tree, tree, uint64_t, bool);
> + const char *, tree, tree,
> + uint64_t, bool, bool);
>
> /* The function type to use for functions that are resolved by
> function_resolver. */
> diff --git a/gcc/testsuite/g++.target/aarch64/sve/pr99216.C
> b/gcc/testsuite/g++.target/aarch64/sve/pr99216.C
> new file mode 100644
> index 00000000000..61a58a7fcf4
> --- /dev/null
> +++ b/gcc/testsuite/g++.target/aarch64/sve/pr99216.C
> @@ -0,0 +1,5 @@
> +/* { dg-do link { target aarch64_asm_sve_ok } } */
> +/* { dg-additional-options "-flto" } */
> +#include <arm_sve.h>
> +bool a;
> +int main() { a = svaddv(svptrue_b8(), svdup_s8(0)); }
--
Alex
