diff options
Diffstat (limited to 'gcc/cp')
| -rw-r--r-- | gcc/cp/constexpr.cc | 90 | ||||
| -rw-r--r-- | gcc/cp/cp-gimplify.cc | 44 | ||||
| -rw-r--r-- | gcc/cp/cp-tree.h | 4 | ||||
| -rw-r--r-- | gcc/cp/parser.cc | 101 | ||||
| -rw-r--r-- | gcc/cp/pt.cc | 27 | ||||
| -rw-r--r-- | gcc/cp/semantics.cc | 75 |
6 files changed, 250 insertions, 91 deletions
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index db7571d..06dcd71 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -38,6 +38,7 @@ along with GCC; see the file COPYING3. If not see #include "opts.h" #include "stringpool.h" #include "attribs.h" +#include "fold-const.h" static bool verify_constant (tree, bool, bool *, bool *); #define VERIFY_CONSTANT(X) \ @@ -1818,6 +1819,52 @@ cx_error_context (void) return r; } +/* If we have a condition in conjunctive normal form (CNF), find the first + failing clause. In other words, given an expression like + + true && true && false && true && false + + return the first 'false'. EXPR is the expression. */ + +static tree +find_failing_clause_r (constexpr_ctx *ctx, tree expr) +{ + if (TREE_CODE (expr) == TRUTH_ANDIF_EXPR) + { + /* First check the left side... */ + tree e = find_failing_clause_r (ctx, TREE_OPERAND (expr, 0)); + if (e == NULL_TREE) + /* ...if we didn't find a false clause, check the right side. */ + e = find_failing_clause_r (ctx, TREE_OPERAND (expr, 1)); + return e; + } + tree e = contextual_conv_bool (expr, tf_none); + if (ctx) + { + bool new_non_constant_p = false, new_overflow_p = false; + e = cxx_eval_constant_expression (ctx, e, vc_prvalue, + &new_non_constant_p, + &new_overflow_p); + } + else + e = fold_non_dependent_expr (e, tf_none, /*manifestly_const_eval=*/true); + if (integer_zerop (e)) + /* This is the failing clause. */ + return expr; + return NULL_TREE; +} + +/* Wrapper for find_failing_clause_r. */ + +tree +find_failing_clause (constexpr_ctx *ctx, tree expr) +{ + if (TREE_CODE (expr) == TRUTH_ANDIF_EXPR) + if (tree e = find_failing_clause_r (ctx, expr)) + expr = e; + return expr; +} + /* Evaluate a call T to a GCC internal function when possible and return the evaluated result or, under the control of CTX, give an error, set NON_CONSTANT_P, and return the unevaluated call T otherwise. */ @@ -1837,6 +1884,48 @@ cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, case IFN_FALLTHROUGH: return void_node; + case IFN_ASSUME: + /* For now, restrict constexpr evaluation of [[assume (cond)]] + only to the cases which don't have side-effects. Evaluating + it even when it does would mean we'd need to somehow undo + all the side-effects e.g. in ctx->global->values. */ + if (!TREE_SIDE_EFFECTS (CALL_EXPR_ARG (t, 0)) + /* And it needs to be a potential constant expression. */ + && potential_rvalue_constant_expression (CALL_EXPR_ARG (t, 0))) + { + constexpr_ctx new_ctx = *ctx; + new_ctx.quiet = true; + tree arg = CALL_EXPR_ARG (t, 0); + bool new_non_constant_p = false, new_overflow_p = false; + arg = cxx_eval_constant_expression (&new_ctx, arg, vc_prvalue, + &new_non_constant_p, + &new_overflow_p); + if (!new_non_constant_p && !new_overflow_p && integer_zerop (arg)) + { + if (!*non_constant_p && !ctx->quiet) + { + /* See if we can find which clause was failing + (for logical AND). */ + tree bad = find_failing_clause (&new_ctx, + CALL_EXPR_ARG (t, 0)); + /* If not, or its location is unusable, fall back to the + previous location. */ + location_t cloc = cp_expr_loc_or_loc (bad, EXPR_LOCATION (t)); + + auto_diagnostic_group d; + + /* Report the error. */ + error_at (cloc, + "failed %<assume%> attribute assumption"); + diagnose_failing_condition (bad, cloc, false); + } + + *non_constant_p = true; + return t; + } + } + return void_node; + case IFN_ADD_OVERFLOW: opcode = PLUS_EXPR; break; @@ -8706,6 +8795,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, case IFN_UBSAN_BOUNDS: case IFN_UBSAN_VPTR: case IFN_FALLTHROUGH: + case IFN_ASSUME: return true; case IFN_ADD_OVERFLOW: diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc index 404a769..b4599fc3 100644 --- a/gcc/cp/cp-gimplify.cc +++ b/gcc/cp/cp-gimplify.cc @@ -3081,6 +3081,50 @@ process_stmt_hotness_attribute (tree std_attrs, location_t attrs_loc) return std_attrs; } +/* If [[assume (cond)]] appears on this statement, handle it. */ + +tree +process_stmt_assume_attribute (tree std_attrs, tree statement, + location_t attrs_loc) +{ + if (std_attrs == error_mark_node) + return std_attrs; + tree attr = lookup_attribute ("gnu", "assume", std_attrs); + if (!attr) + return std_attrs; + /* The next token after the assume attribute is not ';'. */ + if (statement) + { + warning_at (attrs_loc, OPT_Wattributes, + "%<assume%> attribute not followed by %<;%>"); + attr = NULL_TREE; + } + for (; attr; attr = lookup_attribute ("gnu", "assume", TREE_CHAIN (attr))) + { + tree args = TREE_VALUE (attr); + int nargs = list_length (args); + if (nargs != 1) + { + auto_diagnostic_group d; + error_at (attrs_loc, "wrong number of arguments specified for " + "%qE attribute", get_attribute_name (attr)); + inform (attrs_loc, "expected %i, found %i", 1, nargs); + } + else + { + tree arg = TREE_VALUE (args); + if (!type_dependent_expression_p (arg)) + arg = contextual_conv_bool (arg, tf_warning_or_error); + if (error_operand_p (arg)) + continue; + statement = build_call_expr_internal_loc (attrs_loc, IFN_ASSUME, + void_type_node, 1, arg); + finish_expr_stmt (statement); + } + } + return remove_attribute ("gnu", "assume", std_attrs); +} + /* Helper of fold_builtin_source_location, return the std::source_location::__impl type after performing verification on it. LOC is used for reporting any errors. */ diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 8cf9707..8bc1c2d 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -7715,6 +7715,7 @@ extern tree build_transaction_expr (location_t, tree, int, tree); extern bool cxx_omp_create_clause_info (tree, tree, bool, bool, bool, bool); extern tree baselink_for_fns (tree); +extern void diagnose_failing_condition (tree, location_t, bool); extern void finish_static_assert (tree, tree, location_t, bool, bool); extern tree finish_decltype_type (tree, bool, tsubst_flags_t); @@ -8242,6 +8243,7 @@ extern tree predeclare_vla (tree); extern void clear_fold_cache (void); extern tree lookup_hotness_attribute (tree); extern tree process_stmt_hotness_attribute (tree, location_t); +extern tree process_stmt_assume_attribute (tree, tree, location_t); extern bool simple_empty_class_p (tree, tree, tree_code); extern tree fold_builtin_source_location (location_t); @@ -8447,6 +8449,8 @@ extern tree fold_sizeof_expr (tree); extern void clear_cv_and_fold_caches (void); extern tree unshare_constructor (tree CXX_MEM_STAT_INFO); extern bool decl_implicit_constexpr_p (tree); +struct constexpr_ctx; +extern tree find_failing_clause (constexpr_ctx *ctx, tree); extern bool replace_decl (tree *, tree, tree); /* An RAII sentinel used to restrict constexpr evaluation so that it diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc index 7b41635..baa808a 100644 --- a/gcc/cp/parser.cc +++ b/gcc/cp/parser.cc @@ -2258,7 +2258,7 @@ static vec<tree, va_gc> *cp_parser_parenthesized_expression_list (cp_parser *, int, bool, bool, bool *, location_t * = NULL, bool = false); /* Values for the second parameter of cp_parser_parenthesized_expression_list. */ -enum { non_attr = 0, normal_attr = 1, id_attr = 2 }; +enum { non_attr = 0, normal_attr = 1, id_attr = 2, assume_attr = 3 }; static void cp_parser_pseudo_destructor_name (cp_parser *, tree, tree *, tree *); static cp_expr cp_parser_unary_expression @@ -2287,6 +2287,7 @@ static cp_expr cp_parser_binary_expression (cp_parser *, bool, bool, enum cp_parser_prec, cp_id_kind *); static tree cp_parser_question_colon_clause (cp_parser *, cp_expr); +static cp_expr cp_parser_conditional_expression (cp_parser *); static cp_expr cp_parser_assignment_expression (cp_parser *, cp_id_kind * = NULL, bool = false, bool = false); static enum tree_code cp_parser_assignment_operator_opt @@ -8480,7 +8481,6 @@ cp_parser_parenthesized_expression_list (cp_parser* parser, bool wrap_locations_p) { vec<tree, va_gc> *expression_list; - tree identifier = NULL_TREE; bool saved_greater_than_is_operator_p; /* Assume all the expressions will be constant. */ @@ -8509,33 +8509,26 @@ cp_parser_parenthesized_expression_list (cp_parser* parser, next token is an identifier. */ if (is_attribute_list == id_attr && cp_lexer_peek_token (parser->lexer)->type == CPP_NAME) - { - cp_token *token; - - /* Consume the identifier. */ - token = cp_lexer_consume_token (parser->lexer); - /* Save the identifier. */ - identifier = token->u.value; - } + expr = cp_lexer_consume_token (parser->lexer)->u.value; + else if (is_attribute_list == assume_attr) + expr = cp_parser_conditional_expression (parser); else - { - expr - = cp_parser_parenthesized_expression_list_elt (parser, cast_p, - allow_expansion_p, - non_constant_p); + expr + = cp_parser_parenthesized_expression_list_elt (parser, cast_p, + allow_expansion_p, + non_constant_p); - if (wrap_locations_p) - expr.maybe_add_location_wrapper (); + if (wrap_locations_p) + expr.maybe_add_location_wrapper (); - /* Add it to the list. We add error_mark_node - expressions to the list, so that we can still tell if - the correct form for a parenthesized expression-list - is found. That gives better errors. */ - vec_safe_push (expression_list, expr.get_value ()); + /* Add it to the list. We add error_mark_node + expressions to the list, so that we can still tell if + the correct form for a parenthesized expression-list + is found. That gives better errors. */ + vec_safe_push (expression_list, expr.get_value ()); - if (expr == error_mark_node) - goto skip_comma; - } + if (expr == error_mark_node) + goto skip_comma; /* After the first item, attribute lists look the same as expression lists. */ @@ -8577,9 +8570,6 @@ cp_parser_parenthesized_expression_list (cp_parser* parser, parser->greater_than_is_operator_p = saved_greater_than_is_operator_p; - if (identifier) - vec_safe_insert (expression_list, 0, identifier); - return expression_list; } @@ -10310,7 +10300,8 @@ cp_parser_binary_expression (cp_parser* parser, bool cast_p, logical-or-expression that started the conditional-expression. Returns a representation of the entire conditional-expression. - This routine is used by cp_parser_assignment_expression. + This routine is used by cp_parser_assignment_expression + and cp_parser_conditional_expression. ? expression : assignment-expression @@ -10377,6 +10368,28 @@ cp_parser_question_colon_clause (cp_parser* parser, cp_expr logical_or_expr) tf_warning_or_error); } +/* Parse a conditional-expression. + + conditional-expression: + logical-or-expression + logical-or-expression ? expression : assignment-expression + + GNU Extensions: + + logical-or-expression ? : assignment-expression */ + +static cp_expr +cp_parser_conditional_expression (cp_parser *parser) +{ + cp_expr expr = cp_parser_binary_expression (parser, false, false, false, + PREC_NOT_OPERATOR, NULL); + /* If the next token is a `?' then we're actually looking at + a conditional-expression; otherwise we're done. */ + if (cp_lexer_next_token_is (parser->lexer, CPP_QUERY)) + return cp_parser_question_colon_clause (parser, expr); + return expr; +} + /* Parse an assignment-expression. assignment-expression: @@ -10702,15 +10715,7 @@ cp_parser_constant_expression (cp_parser* parser, determine whether a particular assignment-expression is in fact constant. */ if (strict_p) - { - /* Parse the binary expressions (logical-or-expression). */ - expression = cp_parser_binary_expression (parser, false, false, false, - PREC_NOT_OPERATOR, NULL); - /* If the next token is a `?' then we're actually looking at - a conditional-expression; otherwise we're done. */ - if (cp_lexer_next_token_is (parser->lexer, CPP_QUERY)) - expression = cp_parser_question_colon_clause (parser, expression); - } + expression = cp_parser_conditional_expression (parser); else expression = cp_parser_assignment_expression (parser); /* Restore the old settings. */ @@ -12503,6 +12508,9 @@ cp_parser_statement (cp_parser* parser, tree in_statement_expr, /* Look for an expression-statement instead. */ statement = cp_parser_expression_statement (parser, in_statement_expr); + std_attrs = process_stmt_assume_attribute (std_attrs, statement, + attrs_loc); + /* Handle [[fallthrough]];. */ if (attribute_fallthrough_p (std_attrs)) { @@ -12526,7 +12534,7 @@ cp_parser_statement (cp_parser* parser, tree in_statement_expr, if (statement && STATEMENT_CODE_P (TREE_CODE (statement))) SET_EXPR_LOCATION (statement, statement_location); - /* Allow "[[fallthrough]];", but warn otherwise. */ + /* Allow "[[fallthrough]];" or "[[assume(cond)]];", but warn otherwise. */ if (std_attrs != NULL_TREE) warning_at (attrs_loc, OPT_Wattributes, @@ -12718,6 +12726,8 @@ cp_parser_expression_statement (cp_parser* parser, tree in_statement_expr) } } + attr = process_stmt_assume_attribute (attr, statement, loc); + /* Handle [[fallthrough]];. */ if (attribute_fallthrough_p (attr)) { @@ -28876,6 +28886,8 @@ cp_parser_gnu_attribute_list (cp_parser* parser, bool exactly_one /* = false */) vec<tree, va_gc> *vec; int attr_flag = (attribute_takes_identifier_p (identifier) ? id_attr : normal_attr); + if (is_attribute_p ("assume", identifier)) + attr_flag = assume_attr; vec = cp_parser_parenthesized_expression_list (parser, attr_flag, /*cast_p=*/false, /*allow_expansion_p=*/false, @@ -29127,6 +29139,9 @@ cp_parser_std_attribute (cp_parser *parser, tree attr_ns) /* C++17 fallthrough attribute is equivalent to GNU's. */ else if (is_attribute_p ("fallthrough", attr_id)) TREE_PURPOSE (TREE_PURPOSE (attribute)) = gnu_identifier; + /* C++23 assume attribute is equivalent to GNU's. */ + else if (is_attribute_p ("assume", attr_id)) + TREE_PURPOSE (TREE_PURPOSE (attribute)) = gnu_identifier; /* Transactional Memory TS optimize_for_synchronized attribute is equivalent to GNU transaction_callable. */ else if (is_attribute_p ("optimize_for_synchronized", attr_id)) @@ -29171,8 +29186,12 @@ cp_parser_std_attribute (cp_parser *parser, tree attr_ns) return error_mark_node; } - if (attr_ns == gnu_identifier - && attribute_takes_identifier_p (attr_id)) + if (is_attribute_p ("assume", attr_id) + && (attr_ns == NULL_TREE || attr_ns == gnu_identifier)) + /* The assume attribute needs special handling of the argument. */ + attr_flag = assume_attr; + else if (attr_ns == gnu_identifier + && attribute_takes_identifier_p (attr_id)) /* A GNU attribute that takes an identifier in parameter. */ attr_flag = id_attr; diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index bce2a77..bf4ae02 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -21163,6 +21163,33 @@ tsubst_copy_and_build (tree t, break; } + case IFN_ASSUME: + gcc_assert (nargs == 1); + if (vec_safe_length (call_args) != 1) + { + error_at (cp_expr_loc_or_input_loc (t), + "wrong number of arguments to " + "%<assume%> attribute"); + ret = error_mark_node; + } + else + { + tree &arg = (*call_args)[0]; + if (!type_dependent_expression_p (arg)) + arg = contextual_conv_bool (arg, tf_warning_or_error); + if (error_operand_p (arg)) + { + ret = error_mark_node; + break; + } + ret = build_call_expr_internal_loc (EXPR_LOCATION (t), + IFN_ASSUME, + void_type_node, 1, + arg); + RETURN (ret); + } + break; + default: /* Unsupported internal function with arguments. */ gcc_unreachable (); diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc index 30cf2f9..39b11ee 100644 --- a/gcc/cp/semantics.cc +++ b/gcc/cp/semantics.cc @@ -11172,42 +11172,31 @@ init_cp_semantics (void) } -/* If we have a condition in conjunctive normal form (CNF), find the first - failing clause. In other words, given an expression like +/* Emit additional diagnostics for failing condition BAD. + Used by finish_static_assert and IFN_ASSUME constexpr diagnostics. + If SHOW_EXPR_P is true, print the condition (because it was + instantiation-dependent). */ - true && true && false && true && false - - return the first 'false'. EXPR is the expression. */ - -static tree -find_failing_clause_r (tree expr) +void +diagnose_failing_condition (tree bad, location_t cloc, bool show_expr_p) { - if (TREE_CODE (expr) == TRUTH_ANDIF_EXPR) + /* Nobody wants to see the artificial (bool) cast. */ + bad = tree_strip_nop_conversions (bad); + + /* Actually explain the failure if this is a concept check or a + requires-expression. */ + if (concept_check_p (bad) || TREE_CODE (bad) == REQUIRES_EXPR) + diagnose_constraints (cloc, bad, NULL_TREE); + else if (COMPARISON_CLASS_P (bad) + && ARITHMETIC_TYPE_P (TREE_TYPE (TREE_OPERAND (bad, 0)))) { - /* First check the left side... */ - tree e = find_failing_clause_r (TREE_OPERAND (expr, 0)); - if (e == NULL_TREE) - /* ...if we didn't find a false clause, check the right side. */ - e = find_failing_clause_r (TREE_OPERAND (expr, 1)); - return e; + tree op0 = fold_non_dependent_expr (TREE_OPERAND (bad, 0)); + tree op1 = fold_non_dependent_expr (TREE_OPERAND (bad, 1)); + tree cond = build2 (TREE_CODE (bad), boolean_type_node, op0, op1); + inform (cloc, "the comparison reduces to %qE", cond); } - tree e = contextual_conv_bool (expr, tf_none); - e = fold_non_dependent_expr (e, tf_none, /*manifestly_const_eval=*/true); - if (integer_zerop (e)) - /* This is the failing clause. */ - return expr; - return NULL_TREE; -} - -/* Wrapper for find_failing_clause_r. */ - -static tree -find_failing_clause (tree expr) -{ - if (TREE_CODE (expr) == TRUTH_ANDIF_EXPR) - if (tree e = find_failing_clause_r (expr)) - expr = e; - return expr; + else if (show_expr_p) + inform (cloc, "%qE evaluates to false", bad); } /* Build a STATIC_ASSERT for a static assertion with the condition @@ -11274,12 +11263,12 @@ finish_static_assert (tree condition, tree message, location_t location, int len = TREE_STRING_LENGTH (message) / sz - 1; /* See if we can find which clause was failing (for logical AND). */ - tree bad = find_failing_clause (orig_condition); + tree bad = find_failing_clause (NULL, orig_condition); /* If not, or its location is unusable, fall back to the previous location. */ location_t cloc = cp_expr_loc_or_loc (bad, location); - /* Nobody wants to see the artificial (bool) cast. */ - bad = tree_strip_nop_conversions (bad); + + auto_diagnostic_group d; /* Report the error. */ if (len == 0) @@ -11288,21 +11277,7 @@ finish_static_assert (tree condition, tree message, location_t location, error_at (cloc, "static assertion failed: %s", TREE_STRING_POINTER (message)); - /* Actually explain the failure if this is a concept check or a - requires-expression. */ - if (concept_check_p (bad) - || TREE_CODE (bad) == REQUIRES_EXPR) - diagnose_constraints (location, bad, NULL_TREE); - else if (COMPARISON_CLASS_P (bad) - && ARITHMETIC_TYPE_P (TREE_TYPE (TREE_OPERAND (bad, 0)))) - { - tree op0 = fold_non_dependent_expr (TREE_OPERAND (bad, 0)); - tree op1 = fold_non_dependent_expr (TREE_OPERAND (bad, 1)); - tree cond = build2 (TREE_CODE (bad), boolean_type_node, op0, op1); - inform (cloc, "the comparison reduces to %qE", cond); - } - else if (show_expr_p) - inform (cloc, "%qE evaluates to false", bad); + diagnose_failing_condition (bad, cloc, show_expr_p); } else if (condition && condition != error_mark_node) { |