From 10acaf4db9f8b54bd55fb7a6f5b6bb39a91fb9b8 Mon Sep 17 00:00:00 2001 From: Jason Merrill Date: Wed, 31 Jul 2019 14:50:00 -0400 Subject: [PATCH] PR c++/90538 - multiple expansions of capture packs Previously, with init-capture the type of the closure field was a DECLTYPE_TYPE of the initializer. But since each time we tsubst a lambda we get a different lambda, that meant that if the initializer is a lambda, we'd end up with different closure types in the field and initializer after substitution (PR 87322). We dealt with this by remembering the lambda instantiation within each pack expansion element, using local_specialization_stack to separate the elements. But that broke this testcase, because it lost lambda capture proxies that also use local_specializations. So, this patch removes the local_specializations changes from that patch and fixes 87322 differently, by giving init-capture fields 'auto' type and doing deduction later. There's a bit of a kludge to get the right number of fields by pretending that 'auto...' uses the parameter packs from the initializer, but it does the trick. * cp-tree.h (DECLTYPE_FOR_INIT_CAPTURE): Remove. * lambda.c (add_capture): Copy parameter packs from init. (lambda_capture_field_type): Always use auto for init-capture. * pt.c (uses_parameter_packs): Return tree. (tsubst) [DECLTYPE_TYPE]: Remove init-capture handling. (gen_elem_of_pack_expansion_instantiation): Don't push local_specialization_stack. (prepend_one_capture): New. (tsubst_lambda_expr): Use it. Don't touch local_specializations. (do_auto_deduction): Avoid redundant error. From-SVN: r273944 --- gcc/cp/ChangeLog | 12 +++ gcc/cp/cp-tree.h | 9 +-- gcc/cp/lambda.c | 30 +++++--- gcc/cp/pt.c | 73 ++++++++++--------- .../g++.dg/cpp0x/lambda/lambda-variadic9.C | 16 ++++ gcc/testsuite/g++.dg/cpp0x/range-for19.C | 2 +- gcc/testsuite/g++.dg/cpp1y/lambda-init16.C | 2 +- 7 files changed, 91 insertions(+), 53 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic9.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 06024eb506d..e30cc6d8d77 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,5 +1,17 @@ 2019-07-31 Jason Merrill + PR c++/90538 - multiple expansions of capture packs + * cp-tree.h (DECLTYPE_FOR_INIT_CAPTURE): Remove. + * lambda.c (add_capture): Copy parameter packs from init. + (lambda_capture_field_type): Always use auto for init-capture. + * pt.c (uses_parameter_packs): Return tree. + (tsubst) [DECLTYPE_TYPE]: Remove init-capture handling. + (gen_elem_of_pack_expansion_instantiation): Don't push + local_specialization_stack. + (prepend_one_capture): New. + (tsubst_lambda_expr): Use it. Don't touch local_specializations. + (do_auto_deduction): Avoid redundant error. + Fix copy_node of TEMPLATE_INFO. * cp-tree.h (struct tree_template_info): Use tree_base instead of tree_common. Add tmpl and args fields. diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index c8fa29938e4..c6a1eff9ce1 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -423,7 +423,6 @@ extern GTY(()) tree cp_global_trees[CPTI_MAX]; LAMBDA_EXPR_MUTABLE_P (in LAMBDA_EXPR) DECL_FINAL_P (in FUNCTION_DECL) QUALIFIED_NAME_IS_TEMPLATE (in SCOPE_REF) - DECLTYPE_FOR_INIT_CAPTURE (in DECLTYPE_TYPE) CONSTRUCTOR_IS_DEPENDENT (in CONSTRUCTOR) TINFO_USED_TEMPLATE_ID (in TEMPLATE_INFO) PACK_EXPANSION_SIZEOF_P (in *_PACK_EXPANSION) @@ -4484,12 +4483,10 @@ more_aggr_init_expr_args_p (const aggr_init_expr_arg_iterator *iter) (DECLTYPE_TYPE_CHECK (NODE))->type_common.string_flag /* These flags indicate that we want different semantics from normal - decltype: lambda capture just drops references, init capture - uses auto semantics, lambda proxies look through implicit dereference. */ + decltype: lambda capture just drops references, + lambda proxies look through implicit dereference. */ #define DECLTYPE_FOR_LAMBDA_CAPTURE(NODE) \ TREE_LANG_FLAG_0 (DECLTYPE_TYPE_CHECK (NODE)) -#define DECLTYPE_FOR_INIT_CAPTURE(NODE) \ - TREE_LANG_FLAG_1 (DECLTYPE_TYPE_CHECK (NODE)) #define DECLTYPE_FOR_LAMBDA_PROXY(NODE) \ TREE_LANG_FLAG_2 (DECLTYPE_TYPE_CHECK (NODE)) #define DECLTYPE_FOR_REF_CAPTURE(NODE) \ @@ -6794,7 +6791,7 @@ extern bool maybe_instantiate_noexcept (tree, tsubst_flags_t = tf_warning_or_er extern tree instantiate_decl (tree, bool, bool); extern int comp_template_parms (const_tree, const_tree); extern bool builtin_pack_fn_p (tree); -extern bool uses_parameter_packs (tree); +extern tree uses_parameter_packs (tree); extern bool template_parameter_pack_p (const_tree); extern bool function_parameter_pack_p (const_tree); extern bool function_parameter_expanded_from_pack_p (tree, tree); diff --git a/gcc/cp/lambda.c b/gcc/cp/lambda.c index 758773b8a85..c4fed168269 100644 --- a/gcc/cp/lambda.c +++ b/gcc/cp/lambda.c @@ -213,16 +213,7 @@ lambda_capture_field_type (tree expr, bool explicit_init_p, tree type; bool is_this = is_this_parameter (tree_strip_nop_conversions (expr)); - if (!is_this && type_dependent_expression_p (expr)) - { - type = cxx_make_type (DECLTYPE_TYPE); - DECLTYPE_TYPE_EXPR (type) = expr; - DECLTYPE_FOR_LAMBDA_CAPTURE (type) = true; - DECLTYPE_FOR_INIT_CAPTURE (type) = explicit_init_p; - DECLTYPE_FOR_REF_CAPTURE (type) = by_reference_p; - SET_TYPE_STRUCTURAL_EQUALITY (type); - } - else if (!is_this && explicit_init_p) + if (!is_this && explicit_init_p) { tree auto_node = make_auto (); @@ -233,6 +224,14 @@ lambda_capture_field_type (tree expr, bool explicit_init_p, type = build_reference_type (type); type = do_auto_deduction (type, expr, auto_node); } + else if (!is_this && type_dependent_expression_p (expr)) + { + type = cxx_make_type (DECLTYPE_TYPE); + DECLTYPE_TYPE_EXPR (type) = expr; + DECLTYPE_FOR_LAMBDA_CAPTURE (type) = true; + DECLTYPE_FOR_REF_CAPTURE (type) = by_reference_p; + SET_TYPE_STRUCTURAL_EQUALITY (type); + } else { type = non_reference (unlowered_expr_type (expr)); @@ -594,7 +593,16 @@ add_capture (tree lambda, tree id, tree orig_init, bool by_reference_p, name = get_identifier (buf); if (variadic) - type = make_pack_expansion (type); + { + type = make_pack_expansion (type); + if (explicit_init_p) + /* With an explicit initializer 'type' is auto, which isn't really a + parameter pack in this context. We will want as many fields as we + have elements in the expansion of the initializer, so use its packs + instead. */ + PACK_EXPANSION_PARAMETER_PACKS (type) + = uses_parameter_packs (initializer); + } /* Make member variable. */ member = build_decl (input_location, FIELD_DECL, name, type); diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index deaac576468..91a46745447 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -3872,7 +3872,7 @@ find_parameter_packs_r (tree *tp, int *walk_subtrees, void* data) } /* Determines if the expression or type T uses any parameter packs. */ -bool +tree uses_parameter_packs (tree t) { tree parameter_packs = NULL_TREE; @@ -3882,7 +3882,7 @@ uses_parameter_packs (tree t) ppd.type_pack_expansion_p = false; cp_walk_tree (&t, &find_parameter_packs_r, &ppd, ppd.visited); delete ppd.visited; - return parameter_packs != NULL_TREE; + return parameter_packs; } /* Turn ARG, which may be an expression, type, or a TREE_LIST @@ -11764,10 +11764,6 @@ gen_elem_of_pack_expansion_instantiation (tree pattern, ARGUMENT_PACK_SELECT_INDEX (aps) = index; } - // Any local specialization bindings arising from this substitution - // cannot be reused for a different INDEX. - local_specialization_stack lss (lss_copy); - /* Substitute into the PATTERN with the (possibly altered) arguments. */ if (pattern == in_decl) @@ -15139,24 +15135,12 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) /*function_p*/false, /*integral_constant_expression*/false); - if (DECLTYPE_FOR_INIT_CAPTURE (t)) - { - if (type == NULL_TREE) - { - if (complain & tf_error) - error ("empty initializer in lambda init-capture"); - type = error_mark_node; - } - else if (TREE_CODE (type) == TREE_LIST) - type = build_x_compound_expr_from_list (type, ELK_INIT, complain); - } - --cp_unevaluated_operand; --c_inhibit_evaluation_warnings; if (DECLTYPE_FOR_LAMBDA_CAPTURE (t)) type = lambda_capture_field_type (type, - DECLTYPE_FOR_INIT_CAPTURE (t), + false /*explicit_init*/, DECLTYPE_FOR_REF_CAPTURE (t)); else if (DECLTYPE_FOR_LAMBDA_PROXY (t)) type = lambda_proxy_type (type); @@ -18023,6 +18007,33 @@ tsubst_non_call_postfix_expression (tree t, tree args, return t; } +/* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the + LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously + dependent init-capture. */ + +static void +prepend_one_capture (tree field, tree init, tree &list, + tsubst_flags_t complain) +{ + if (tree auto_node = type_uses_auto (TREE_TYPE (field))) + { + tree type = NULL_TREE; + if (!init) + { + if (complain & tf_error) + error ("empty initializer in lambda init-capture"); + init = error_mark_node; + } + else if (TREE_CODE (init) == TREE_LIST) + init = build_x_compound_expr_from_list (init, ELK_INIT, complain); + if (!type) + type = do_auto_deduction (TREE_TYPE (field), init, auto_node, complain); + TREE_TYPE (field) = type; + cp_apply_type_quals_to_decl (cp_type_quals (type), field); + } + list = tree_cons (field, init, list); +} + /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current instantiation context. Instantiating a pack expansion containing a lambda might result in multiple lambdas all based on the same lambda in the @@ -18034,17 +18045,8 @@ tsubst_lambda_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl) tree oldfn = lambda_function (t); in_decl = oldfn; - /* If we have already specialized this lambda expr, reuse it. See - PR c++/87322. */ - if (local_specializations) - if (tree r = retrieve_local_specialization (t)) - return r; - tree r = build_lambda_expr (); - if (local_specializations) - register_local_specialization (r, t); - LAMBDA_EXPR_LOCATION (r) = LAMBDA_EXPR_LOCATION (t); LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (r) @@ -18097,15 +18099,15 @@ tsubst_lambda_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl) gcc_assert (TREE_CODE (init) == TREE_VEC && TREE_VEC_LENGTH (init) == len); for (int i = 0; i < len; ++i) - LAMBDA_EXPR_CAPTURE_LIST (r) - = tree_cons (TREE_VEC_ELT (field, i), - TREE_VEC_ELT (init, i), - LAMBDA_EXPR_CAPTURE_LIST (r)); + prepend_one_capture (TREE_VEC_ELT (field, i), + TREE_VEC_ELT (init, i), + LAMBDA_EXPR_CAPTURE_LIST (r), + complain); } else { - LAMBDA_EXPR_CAPTURE_LIST (r) - = tree_cons (field, init, LAMBDA_EXPR_CAPTURE_LIST (r)); + prepend_one_capture (field, init, LAMBDA_EXPR_CAPTURE_LIST (r), + complain); if (id_equal (DECL_NAME (field), "__this")) LAMBDA_EXPR_THIS_CAPTURE (r) = field; @@ -27602,6 +27604,9 @@ do_auto_deduction (tree type, tree init, tree auto_node, } else { + if (error_operand_p (init)) + return error_mark_node; + tree parms = build_tree_list (NULL_TREE, type); tree tparms; diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic9.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic9.C new file mode 100644 index 00000000000..8c5085cf0f1 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic9.C @@ -0,0 +1,16 @@ +// PR c++/90538 +// { dg-do compile { target c++11 } } + +template +void f(Ts... ts) +{ + [=]{ + f(ts...); + f(ts...); + }(); +} + +void g() +{ + f(1); +} diff --git a/gcc/testsuite/g++.dg/cpp0x/range-for19.C b/gcc/testsuite/g++.dg/cpp0x/range-for19.C index e3f446f3700..6afaee577f2 100644 --- a/gcc/testsuite/g++.dg/cpp0x/range-for19.C +++ b/gcc/testsuite/g++.dg/cpp0x/range-for19.C @@ -5,6 +5,6 @@ int main() { auto a; // { dg-error "no initializer" } - for(auto i: a) // { dg-error "deduce" } + for(auto i: a) ; } diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-init16.C b/gcc/testsuite/g++.dg/cpp1y/lambda-init16.C index 0a40ebbee0f..6b4ed347eee 100644 --- a/gcc/testsuite/g++.dg/cpp1y/lambda-init16.C +++ b/gcc/testsuite/g++.dg/cpp1y/lambda-init16.C @@ -3,7 +3,7 @@ template < class T = int > void f (T) { - auto g = [&a = f] () {}; // { dg-error "invalid initialization" } + auto g = [&a = f] () {}; // { dg-error "auto" } } int main () -- 2.30.2