From: Jason Merrill <jason@redhat.com>
To: Patrick Palka <ppalka@redhat.com>, gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] c++: remove coerce_innermost_template_parms
Date: Fri, 18 Nov 2022 18:52:50 -0500 [thread overview]
Message-ID: <cc9382d8-cad6-c6d1-124a-55deff6819d0@redhat.com> (raw)
In-Reply-To: <20221118215946.3621557-1-ppalka@redhat.com>
On 11/18/22 16:59, Patrick Palka wrote:
> IIUC the only practical difference between coerce_innermost_template_parms
> and the main function coerce_template_parms is that the former takes
> a multi-level template parameter list and returns a template argument
> vector of the same depth, whereas the latter takes a single-level
> template parameter vector and returns a single-level template argument
> vector.
>
> This patch gets rid of the wrapper function and just overloads the
> behavior of the main function according to whether 'parms' is a
> multi-level template parameter list or a single-level template argument
> vector. It turns out we can assume parms and args have the same depth
> in the multi-level case, which simplifies the overloading logic.
>
> Besides the (subjective) simplificatio benefit, another benefit of this
> unification is that it avoids a redundant copy of a multi-level 'args'.
> Now, we can return new_args directly from c_t_p. (And because of this,
> we need to turn new_inner_args into a reference so that updating it also
> updates new_args.)
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> trunk?
OK. But this doesn't really seem like stage 3 material; let's hold off
on further cleanups like this until next stage 1.
> gcc/cp/ChangeLog:
>
> * pt.cc (coerce_template_parms): Salvage part of the function
> comment from c_innermost_t_p. Handle parms being a full
> template parameter list.
> (coerce_innermost_template_parms): Remove.
> (lookup_template_class): Use c_t_p instead of c_innermost_t_p.
> (finish_template_variable): Likewise.
> (tsubst_decl): Likewise.
> (instantiate_alias_template): Likewise.
> ---
> gcc/cp/pt.cc | 92 +++++++++++++++-------------------------------------
> 1 file changed, 27 insertions(+), 65 deletions(-)
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index 0310e38c9b9..2666e455edf 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -148,8 +148,6 @@ static void add_pending_template (tree);
> static tree reopen_tinst_level (struct tinst_level *);
> static tree tsubst_initializer_list (tree, tree);
> static tree get_partial_spec_bindings (tree, tree, tree);
> -static tree coerce_innermost_template_parms (tree, tree, tree, tsubst_flags_t,
> - bool = true);
> static void tsubst_enum (tree, tree, tree);
> static bool check_instantiated_args (tree, tree, tsubst_flags_t);
> static int check_non_deducible_conversion (tree, tree, unification_kind_t, int,
> @@ -8827,6 +8825,14 @@ pack_expansion_args_count (tree args)
> arguments. If any error occurs, return error_mark_node. Error and
> warning messages are issued under control of COMPLAIN.
>
> + If PARMS represents all template parameters levels, this function
> + returns a vector of vectors representing all the resulting argument
> + levels. Note that in this case, only the innermost arguments are
> + coerced because the outermost ones are supposed to have been coerced
> + already. Otherwise, if PARMS represents only (the innermost) vector
> + of parameters, this function returns a vector containing just the
> + innermost resulting arguments.
> +
> If REQUIRE_ALL_ARGS is false, argument deduction will be performed
> for arguments not specified in ARGS. If REQUIRE_ALL_ARGS is true,
> arguments not specified in ARGS must have default arguments which
> @@ -8842,8 +8848,6 @@ coerce_template_parms (tree parms,
> int nparms, nargs, parm_idx, arg_idx, lost = 0;
> tree orig_inner_args;
> tree inner_args;
> - tree new_args;
> - tree new_inner_args;
>
> /* When used as a boolean value, indicates whether this is a
> variadic template parameter list. Since it's an int, we can also
> @@ -8864,6 +8868,17 @@ coerce_template_parms (tree parms,
> if (args == error_mark_node)
> return error_mark_node;
>
> + bool return_full_args = false;
> + if (TREE_CODE (parms) == TREE_LIST)
> + {
> + if (TMPL_PARMS_DEPTH (parms) > 1)
> + {
> + gcc_assert (TMPL_PARMS_DEPTH (parms) == TMPL_ARGS_DEPTH (args));
> + return_full_args = true;
> + }
> + parms = INNERMOST_TEMPLATE_PARMS (parms);
> + }
> +
> nparms = TREE_VEC_LENGTH (parms);
>
> /* Determine if there are any parameter packs or default arguments. */
> @@ -8961,8 +8976,8 @@ coerce_template_parms (tree parms,
> template-id may be nested within a "sizeof". */
> cp_evaluated ev;
>
> - new_inner_args = make_tree_vec (nparms);
> - new_args = add_outermost_template_args (args, new_inner_args);
> + tree new_args = add_outermost_template_args (args, make_tree_vec (nparms));
> + tree& new_inner_args = TMPL_ARGS_LEVEL (new_args, TMPL_ARGS_DEPTH (new_args));
> int pack_adjust = 0;
> for (parm_idx = 0, arg_idx = 0; parm_idx < nparms; parm_idx++, arg_idx++)
> {
> @@ -9164,59 +9179,7 @@ coerce_template_parms (tree parms,
> SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (new_inner_args,
> TREE_VEC_LENGTH (new_inner_args));
>
> - return new_inner_args;
> -}
> -
> -/* Like coerce_template_parms. If PARMS represents all template
> - parameters levels, this function returns a vector of vectors
> - representing all the resulting argument levels. Note that in this
> - case, only the innermost arguments are coerced because the
> - outermost ones are supposed to have been coerced already.
> -
> - Otherwise, if PARMS represents only (the innermost) vector of
> - parameters, this function returns a vector containing just the
> - innermost resulting arguments. */
> -
> -static tree
> -coerce_innermost_template_parms (tree parms,
> - tree args,
> - tree in_decl,
> - tsubst_flags_t complain,
> - bool require_all_args /* = true */)
> -{
> - int parms_depth = TMPL_PARMS_DEPTH (parms);
> - int args_depth = TMPL_ARGS_DEPTH (args);
> - tree coerced_args;
> -
> - if (parms_depth > 1)
> - {
> - coerced_args = make_tree_vec (parms_depth);
> - tree level;
> - int cur_depth;
> -
> - for (level = parms, cur_depth = parms_depth;
> - parms_depth > 0 && level != NULL_TREE;
> - level = TREE_CHAIN (level), --cur_depth)
> - {
> - tree l;
> - if (cur_depth == args_depth)
> - l = coerce_template_parms (TREE_VALUE (level),
> - args, in_decl, complain,
> - require_all_args);
> - else
> - l = TMPL_ARGS_LEVEL (args, cur_depth);
> -
> - if (l == error_mark_node)
> - return error_mark_node;
> -
> - SET_TMPL_ARGS_LEVEL (coerced_args, cur_depth, l);
> - }
> - }
> - else
> - coerced_args = coerce_template_parms (INNERMOST_TEMPLATE_PARMS (parms),
> - args, in_decl, complain,
> - require_all_args);
> - return coerced_args;
> + return return_full_args ? new_args : new_inner_args;
> }
>
> /* Returns true if T is a wrapper to make a C++20 template parameter
> @@ -9909,8 +9872,7 @@ lookup_template_class (tree d1, tree arglist, tree in_decl, tree context,
> /* Calculate the BOUND_ARGS. These will be the args that are
> actually tsubst'd into the definition to create the
> instantiation. */
> - arglist = coerce_innermost_template_parms (parmlist, arglist, gen_tmpl,
> - complain);
> + arglist = coerce_template_parms (parmlist, arglist, gen_tmpl, complain);
>
> if (arglist == error_mark_node)
> /* We were unable to bind the arguments. */
> @@ -10326,7 +10288,7 @@ finish_template_variable (tree var, tsubst_flags_t complain)
> tree arglist = TREE_OPERAND (var, 1);
>
> tree parms = DECL_TEMPLATE_PARMS (templ);
> - arglist = coerce_innermost_template_parms (parms, arglist, templ, complain);
> + arglist = coerce_template_parms (parms, arglist, templ, complain);
> if (arglist == error_mark_node)
> return error_mark_node;
>
> @@ -14962,7 +14924,7 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain)
> /* We're fully specializing a template declaration, so
> we need to coerce the innermost arguments corresponding to
> the template. */
> - argvec = (coerce_innermost_template_parms
> + argvec = (coerce_template_parms
> (DECL_TEMPLATE_PARMS (gen_tmpl),
> argvec, t, complain));
> if (argvec == error_mark_node)
> @@ -21800,8 +21762,8 @@ instantiate_alias_template (tree tmpl, tree args, tsubst_flags_t complain)
> if (tmpl == error_mark_node || args == error_mark_node)
> return error_mark_node;
>
> - args = coerce_innermost_template_parms (DECL_TEMPLATE_PARMS (tmpl),
> - args, tmpl, complain);
> + args = coerce_template_parms (DECL_TEMPLATE_PARMS (tmpl),
> + args, tmpl, complain);
>
> /* FIXME check for satisfaction in check_instantiated_args. */
> if (flag_concepts
prev parent reply other threads:[~2022-11-18 23:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-18 21:59 Patrick Palka
2022-11-18 23:52 ` Jason Merrill [this message]
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