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 /* Common block and equivalence list handling Copyright (C) 2000-2022 Free Software Foundation, Inc. Contributed by Canqun Yang This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see . */ /* The core algorithm is based on Andy Vaught's g95 tree. Also the way to build UNION_TYPE is borrowed from Richard Henderson. Transform common blocks. An integral part of this is processing equivalence variables. Equivalenced variables that are not in a common block end up in a private block of their own. Each common block or local equivalence list is declared as a union. Variables within the block are represented as a field within the block with the proper offset. So if two variables are equivalenced, they just point to a common area in memory. Mathematically, laying out an equivalence block is equivalent to solving a linear system of equations. The matrix is usually a sparse matrix in which each row contains all zero elements except for a +1 and a -1, a sort of a generalized Vandermonde matrix. The matrix is usually block diagonal. The system can be overdetermined, underdetermined or have a unique solution. If the system is inconsistent, the program is not standard conforming. The solution vector is integral, since all of the pivots are +1 or -1. How we lay out an equivalence block is a little less complicated. In an equivalence list with n elements, there are n-1 conditions to be satisfied. The conditions partition the variables into what we will call segments. If A and B are equivalenced then A and B are in the same segment. If B and C are equivalenced as well, then A, B and C are in a segment and so on. Each segment is a block of memory that has one or more variables equivalenced in some way. A common block is made up of a series of segments that are joined one after the other. In the linear system, a segment is a block diagonal. To lay out a segment we first start with some variable and determine its length. The first variable is assumed to start at offset one and extends to however long it is. We then traverse the list of equivalences to find an unused condition that involves at least one of the variables currently in the segment. Each equivalence condition amounts to the condition B+b=C+c where B and C are the offsets of the B and C variables, and b and c are constants which are nonzero for array elements, substrings or structure components. So for EQUIVALENCE(B(2), C(3)) we have B + 2*size of B's elements = C + 3*size of C's elements. If B and C are known we check to see if the condition already holds. If B is known we can solve for C. Since we know the length of C, we can see if the minimum and maximum extents of the segment are affected. Eventually, we make a full pass through the equivalence list without finding any new conditions and the segment is fully specified. At this point, the segment is added to the current common block. Since we know the minimum extent of the segment, everything in the segment is translated to its position in the common block. The usual case here is that there are no equivalence statements and the common block is series of segments with one variable each, which is a diagonal matrix in the matrix formulation. Each segment is described by a chain of segment_info structures. Each segment_info structure describes the extents of a single variable within the segment. This list is maintained in the order the elements are positioned within the segment. If two elements have the same starting offset the smaller will come first. If they also have the same size their ordering is undefined. Once all common blocks have been created, the list of equivalences is examined for still-unused equivalence conditions. We create a block for each merged equivalence list. */ #include "config.h" #define INCLUDE_MAP #include "system.h" #include "coretypes.h" #include "tm.h" #include "tree.h" #include "gfortran.h" #include "trans.h" #include "stringpool.h" #include "fold-const.h" #include "stor-layout.h" #include "varasm.h" #include "trans-types.h" #include "trans-const.h" #include "target-memory.h" /* Holds a single variable in an equivalence set. */ typedef struct segment_info { gfc_symbol *sym; HOST_WIDE_INT offset; HOST_WIDE_INT length; /* This will contain the field type until the field is created. */ tree field; struct segment_info *next; } segment_info; static segment_info * current_segment; /* Store decl of all common blocks in this translation unit; the first tree is the identifier. */ static std::map gfc_map_of_all_commons; /* Make a segment_info based on a symbol. */ static segment_info * get_segment_info (gfc_symbol * sym, HOST_WIDE_INT offset) { segment_info *s; /* Make sure we've got the character length. */ if (sym->ts.type == BT_CHARACTER) gfc_conv_const_charlen (sym->ts.u.cl); /* Create the segment_info and fill it in. */ s = XCNEW (segment_info); s->sym = sym; /* We will use this type when building the segment aggregate type. */ s->field = gfc_sym_type (sym); s->length = int_size_in_bytes (s->field); s->offset = offset; return s; } /* Add a copy of a segment list to the namespace. This is specifically for equivalence segments, so that dependency checking can be done on equivalence group members. */ static void copy_equiv_list_to_ns (segment_info *c) { segment_info *f; gfc_equiv_info *s; gfc_equiv_list *l; l = XCNEW (gfc_equiv_list); l->next = c->sym->ns->equiv_lists; c->sym->ns->equiv_lists = l; for (f = c; f; f = f->next) { s = XCNEW (gfc_equiv_info); s->next = l->equiv; l->equiv = s; s->sym = f->sym; s->offset = f->offset; s->length = f->length; } } /* Add combine segment V and segment LIST. */ static segment_info * add_segments (segment_info *list, segment_info *v) { segment_info *s; segment_info *p; segment_info *next; p = NULL; s = list; while (v) { /* Find the location of the new element. */ while (s) { if (v->offset < s->offset) break; if (v->offset == s->offset && v->length <= s->length) break; p = s; s = s->next; } /* Insert the new element in between p and s. */ next = v->next; v->next = s; if (p == NULL) list = v; else p->next = v; p = v; v = next; } return list; } /* Construct mangled common block name from symbol name. */ /* We need the bind(c) flag to tell us how/if we should mangle the symbol name. There are few calls to this function, so few places that this would need to be added. At the moment, there is only one call, in build_common_decl(). We can't attempt to look up the common block because we may be building it for the first time and therefore, it won't be in the common_root. We also need the binding label, if it's bind(c). Therefore, send in the pointer to the common block, so whatever info we have so far can be used. All of the necessary info should be available in the gfc_common_head by now, so it should be accurate to test the isBindC flag and use the binding label given if it is bind(c). We may NOT know yet if it's bind(c) or not, but we can try at least. Will have to figure out what to do later if it's labeled bind(c) after this is called. */ static tree gfc_sym_mangled_common_id (gfc_common_head *com) { int has_underscore; /* Provide sufficient space to hold "symbol.symbol.eq.1234567890__". */ char mangled_name[2*GFC_MAX_MANGLED_SYMBOL_LEN + 1 + 16 + 1]; char name[sizeof (mangled_name) - 2]; /* Get the name out of the common block pointer. */ size_t len = strlen (com->name); gcc_assert (len < sizeof (name)); strcpy (name, com->name); /* If we're suppose to do a bind(c). */ if (com->is_bind_c == 1 && com->binding_label) return get_identifier (com->binding_label); if (strcmp (name, BLANK_COMMON_NAME) == 0) return get_identifier (name); if (flag_underscoring) { has_underscore = strchr (name, '_') != 0; if (flag_second_underscore && has_underscore) snprintf (mangled_name, sizeof mangled_name, "%s__", name); else snprintf (mangled_name, sizeof mangled_name, "%s_", name); return get_identifier (mangled_name); } else return get_identifier (name); } /* Build a field declaration for a common variable or a local equivalence object. */ static void build_field (segment_info *h, tree union_type, record_layout_info rli) { tree field; tree name; HOST_WIDE_INT offset = h->offset; unsigned HOST_WIDE_INT desired_align, known_align; name = get_identifier (h->sym->name); field = build_decl (gfc_get_location (&h->sym->declared_at), FIELD_DECL, name, h->field); known_align = (offset & -offset) * BITS_PER_UNIT; if (known_align == 0 || known_align > BIGGEST_ALIGNMENT) known_align = BIGGEST_ALIGNMENT; desired_align = update_alignment_for_field (rli, field, known_align); if (desired_align > known_align) DECL_PACKED (field) = 1; DECL_FIELD_CONTEXT (field) = union_type; DECL_FIELD_OFFSET (field) = size_int (offset); DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node; SET_DECL_OFFSET_ALIGN (field, known_align); rli->offset = size_binop (MAX_EXPR, rli->offset, size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (field), DECL_SIZE_UNIT (field))); /* If this field is assigned to a label, we create another two variables. One will hold the address of target label or format label. The other will hold the length of format label string. */ if (h->sym->attr.assign) { tree len; tree addr; gfc_allocate_lang_decl (field); GFC_DECL_ASSIGN (field) = 1; len = gfc_create_var_np (gfc_charlen_type_node,h->sym->name); addr = gfc_create_var_np (pvoid_type_node, h->sym->name); TREE_STATIC (len) = 1; TREE_STATIC (addr) = 1; DECL_INITIAL (len) = build_int_cst (gfc_charlen_type_node, -2); gfc_set_decl_location (len, &h->sym->declared_at); gfc_set_decl_location (addr, &h->sym->declared_at); GFC_DECL_STRING_LEN (field) = pushdecl_top_level (len); GFC_DECL_ASSIGN_ADDR (field) = pushdecl_top_level (addr); } /* If this field is volatile, mark it. */ if (h->sym->attr.volatile_) { tree new_type; TREE_THIS_VOLATILE (field) = 1; TREE_SIDE_EFFECTS (field) = 1; new_type = build_qualified_type (TREE_TYPE (field), TYPE_QUAL_VOLATILE); TREE_TYPE (field) = new_type; } h->field = field; } #if !defined (NO_DOT_IN_LABEL) #define GFC_EQUIV_FMT "equiv.%d" #elif !defined (NO_DOLLAR_IN_LABEL) #define GFC_EQUIV_FMT "_Equiv\$%d" #else #define GFC_EQUIV_FMT "_Equiv_%d" #endif /* Get storage for local equivalence. */ static tree build_equiv_decl (tree union_type, bool is_init, bool is_saved, bool is_auto) { tree decl; char name[18]; static int serial = 0; if (is_init) { decl = gfc_create_var (union_type, "equiv"); TREE_STATIC (decl) = 1; GFC_DECL_COMMON_OR_EQUIV (decl) = 1; return decl; } snprintf (name, sizeof (name), GFC_EQUIV_FMT, serial++); decl = build_decl (input_location, VAR_DECL, get_identifier (name), union_type); DECL_ARTIFICIAL (decl) = 1; DECL_IGNORED_P (decl) = 1; if (!is_auto && (!gfc_can_put_var_on_stack (DECL_SIZE_UNIT (decl)) || is_saved)) TREE_STATIC (decl) = 1; TREE_ADDRESSABLE (decl) = 1; TREE_USED (decl) = 1; GFC_DECL_COMMON_OR_EQUIV (decl) = 1; /* The source location has been lost, and doesn't really matter. We need to set it to something though. */ gfc_set_decl_location (decl, &gfc_current_locus); gfc_add_decl_to_function (decl); return decl; } /* Get storage for common block. */ static tree build_common_decl (gfc_common_head *com, tree union_type, bool is_init) { tree decl, identifier; identifier = gfc_sym_mangled_common_id (com); decl = gfc_map_of_all_commons.count(identifier) ? gfc_map_of_all_commons[identifier] : NULL_TREE; /* Update the size of this common block as needed. */ if (decl != NULL_TREE) { tree size = TYPE_SIZE_UNIT (union_type); /* Named common blocks of the same name shall be of the same size in all scoping units of a program in which they appear, but blank common blocks may be of different sizes. */ if (!tree_int_cst_equal (DECL_SIZE_UNIT (decl), size) && strcmp (com->name, BLANK_COMMON_NAME)) gfc_warning (0, "Named COMMON block %qs at %L shall be of the " "same size as elsewhere (%lu vs %lu bytes)", com->name, &com->where, (unsigned long) TREE_INT_CST_LOW (size), (unsigned long) TREE_INT_CST_LOW (DECL_SIZE_UNIT (decl))); if (tree_int_cst_lt (DECL_SIZE_UNIT (decl), size)) { DECL_SIZE (decl) = TYPE_SIZE (union_type); DECL_SIZE_UNIT (decl) = size; SET_DECL_MODE (decl, TYPE_MODE (union_type)); TREE_TYPE (decl) = union_type; layout_decl (decl, 0); } } /* If this common block has been declared in a previous program unit, and either it is already initialized or there is no new initialization for it, just return. */ if ((decl != NULL_TREE) && (!is_init || DECL_INITIAL (decl))) return decl; /* If there is no backend_decl for the common block, build it. */ if (decl == NULL_TREE) { tree omp_clauses = NULL_TREE; if (com->is_bind_c == 1 && com->binding_label) decl = build_decl (input_location, VAR_DECL, identifier, union_type); else { decl = build_decl (input_location, VAR_DECL, get_identifier (com->name), union_type); gfc_set_decl_assembler_name (decl, identifier); } TREE_PUBLIC (decl) = 1; TREE_STATIC (decl) = 1; DECL_IGNORED_P (decl) = 1; if (!com->is_bind_c) SET_DECL_ALIGN (decl, BIGGEST_ALIGNMENT); else { /* Do not set the alignment for bind(c) common blocks to BIGGEST_ALIGNMENT because that won't match what C does. Also, for common blocks with one element, the alignment must be that of the field within the common block in order to match what C will do. */ tree field = NULL_TREE; field = TYPE_FIELDS (TREE_TYPE (decl)); if (DECL_CHAIN (field) == NULL_TREE) SET_DECL_ALIGN (decl, TYPE_ALIGN (TREE_TYPE (field))); } DECL_USER_ALIGN (decl) = 0; GFC_DECL_COMMON_OR_EQUIV (decl) = 1; gfc_set_decl_location (decl, &com->where); if (com->threadprivate) set_decl_tls_model (decl, decl_default_tls_model (decl)); if (com->omp_device_type != OMP_DEVICE_TYPE_UNSET) { tree c = build_omp_clause (UNKNOWN_LOCATION, OMP_CLAUSE_DEVICE_TYPE); switch (com->omp_device_type) { case OMP_DEVICE_TYPE_HOST: OMP_CLAUSE_DEVICE_TYPE_KIND (c) = OMP_CLAUSE_DEVICE_TYPE_HOST; break; case OMP_DEVICE_TYPE_NOHOST: OMP_CLAUSE_DEVICE_TYPE_KIND (c) = OMP_CLAUSE_DEVICE_TYPE_NOHOST; break; case OMP_DEVICE_TYPE_ANY: OMP_CLAUSE_DEVICE_TYPE_KIND (c) = OMP_CLAUSE_DEVICE_TYPE_ANY; break; default: gcc_unreachable (); } omp_clauses = c; } if (com->omp_declare_target_link) DECL_ATTRIBUTES (decl) = tree_cons (get_identifier ("omp declare target link"), omp_clauses, DECL_ATTRIBUTES (decl)); else if (com->omp_declare_target) DECL_ATTRIBUTES (decl) = tree_cons (get_identifier ("omp declare target"), omp_clauses, DECL_ATTRIBUTES (decl)); /* Place the back end declaration for this common block in GLOBAL_BINDING_LEVEL. */ gfc_map_of_all_commons[identifier] = pushdecl_top_level (decl); } /* Has no initial values. */ if (!is_init) { DECL_INITIAL (decl) = NULL_TREE; DECL_COMMON (decl) = 1; DECL_DEFER_OUTPUT (decl) = 1; } else { DECL_INITIAL (decl) = error_mark_node; DECL_COMMON (decl) = 0; DECL_DEFER_OUTPUT (decl) = 0; } return decl; } /* Return a field that is the size of the union, if an equivalence has overlapping initializers. Merge the initializers into a single initializer for this new field, then free the old ones. */ static tree get_init_field (segment_info *head, tree union_type, tree *field_init, record_layout_info rli) { segment_info *s; HOST_WIDE_INT length = 0; HOST_WIDE_INT offset = 0; unsigned HOST_WIDE_INT known_align, desired_align; bool overlap = false; tree tmp, field; tree init; unsigned char *data, *chk; vec *v = NULL; tree type = unsigned_char_type_node; int i; /* Obtain the size of the union and check if there are any overlapping initializers. */ for (s = head; s; s = s->next) { HOST_WIDE_INT slen = s->offset + s->length; if (s->sym->value) { if (s->offset < offset) overlap = true; offset = slen; } length = length < slen ? slen : length; } if (!overlap) return NULL_TREE; /* Now absorb all the initializer data into a single vector, whilst checking for overlapping, unequal values. */ data = XCNEWVEC (unsigned char, (size_t)length); chk = XCNEWVEC (unsigned char, (size_t)length); /* TODO - change this when default initialization is implemented. */ memset (data, '\0', (size_t)length); memset (chk, '\0', (size_t)length); for (s = head; s; s = s->next) if (s->sym->value) { locus *loc = NULL; if (s->sym->ns->equiv && s->sym->ns->equiv->eq) loc = &s->sym->ns->equiv->eq->expr->where; gfc_merge_initializers (s->sym->ts, s->sym->value, loc, &data[s->offset], &chk[s->offset], (size_t)s->length); } for (i = 0; i < length; i++) CONSTRUCTOR_APPEND_ELT (v, NULL, build_int_cst (type, data[i])); free (data); free (chk); /* Build a char[length] array to hold the initializers. Much of what follows is borrowed from build_field, above. */ tmp = build_int_cst (gfc_array_index_type, length - 1); tmp = build_range_type (gfc_array_index_type, gfc_index_zero_node, tmp); tmp = build_array_type (type, tmp); field = build_decl (gfc_get_location (&gfc_current_locus), FIELD_DECL, NULL_TREE, tmp); known_align = BIGGEST_ALIGNMENT; desired_align = update_alignment_for_field (rli, field, known_align); if (desired_align > known_align) DECL_PACKED (field) = 1; DECL_FIELD_CONTEXT (field) = union_type; DECL_FIELD_OFFSET (field) = size_int (0); DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node; SET_DECL_OFFSET_ALIGN (field, known_align); rli->offset = size_binop (MAX_EXPR, rli->offset, size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (field), DECL_SIZE_UNIT (field))); init = build_constructor (TREE_TYPE (field), v); TREE_CONSTANT (init) = 1; *field_init = init; for (s = head; s; s = s->next) { if (s->sym->value == NULL) continue; gfc_free_expr (s->sym->value); s->sym->value = NULL; } return field; } /* Declare memory for the common block or local equivalence, and create backend declarations for all of the elements. */ static void create_common (gfc_common_head *com, segment_info *head, bool saw_equiv) { segment_info *s, *next_s; tree union_type; tree *field_link; tree field; tree field_init = NULL_TREE; record_layout_info rli; tree decl; bool is_init = false; bool is_saved = false; bool is_auto = false; /* Declare the variables inside the common block. If the current common block contains any equivalence object, then make a UNION_TYPE node, otherwise RECORD_TYPE. This will let the alias analyzer work well when there is no address overlapping for common variables in the current common block. */ if (saw_equiv) union_type = make_node (UNION_TYPE); else union_type = make_node (RECORD_TYPE); rli = start_record_layout (union_type); field_link = &TYPE_FIELDS (union_type); /* Check for overlapping initializers and replace them with a single, artificial field that contains all the data. */ if (saw_equiv) field = get_init_field (head, union_type, &field_init, rli); else field = NULL_TREE; if (field != NULL_TREE) { is_init = true; *field_link = field; field_link = &DECL_CHAIN (field); } for (s = head; s; s = s->next) { build_field (s, union_type, rli); /* Link the field into the type. */ *field_link = s->field; field_link = &DECL_CHAIN (s->field); /* Has initial value. */ if (s->sym->value) is_init = true; /* Has SAVE attribute. */ if (s->sym->attr.save) is_saved = true; /* Has AUTOMATIC attribute. */ if (s->sym->attr.automatic) is_auto = true; } finish_record_layout (rli, true); if (com) decl = build_common_decl (com, union_type, is_init); else decl = build_equiv_decl (union_type, is_init, is_saved, is_auto); if (is_init) { tree ctor, tmp; vec *v = NULL; if (field != NULL_TREE && field_init != NULL_TREE) CONSTRUCTOR_APPEND_ELT (v, field, field_init); else for (s = head; s; s = s->next) { if (s->sym->value) { /* Add the initializer for this field. */ tmp = gfc_conv_initializer (s->sym->value, &s->sym->ts, TREE_TYPE (s->field), s->sym->attr.dimension, s->sym->attr.pointer || s->sym->attr.allocatable, false); CONSTRUCTOR_APPEND_ELT (v, s->field, tmp); } } gcc_assert (!v->is_empty ()); ctor = build_constructor (union_type, v); TREE_CONSTANT (ctor) = 1; TREE_STATIC (ctor) = 1; DECL_INITIAL (decl) = ctor; if (flag_checking) { tree field, value; unsigned HOST_WIDE_INT idx; FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), idx, field, value) gcc_assert (TREE_CODE (field) == FIELD_DECL); } } /* Build component reference for each variable. */ for (s = head; s; s = next_s) { tree var_decl; var_decl = build_decl (gfc_get_location (&s->sym->declared_at), VAR_DECL, DECL_NAME (s->field), TREE_TYPE (s->field)); TREE_STATIC (var_decl) = TREE_STATIC (decl); /* Mark the variable as used in order to avoid warnings about unused variables. */ TREE_USED (var_decl) = 1; if (s->sym->attr.use_assoc) DECL_IGNORED_P (var_decl) = 1; if (s->sym->attr.target) TREE_ADDRESSABLE (var_decl) = 1; /* Fake variables are not visible from other translation units. */ TREE_PUBLIC (var_decl) = 0; gfc_finish_decl_attrs (var_decl, &s->sym->attr); /* To preserve identifier names in COMMON, chain to procedure scope unless at top level in a module definition. */ if (com && s->sym->ns->proc_name && s->sym->ns->proc_name->attr.flavor == FL_MODULE) var_decl = pushdecl_top_level (var_decl); else gfc_add_decl_to_function (var_decl); tree comp = build3_loc (input_location, COMPONENT_REF, TREE_TYPE (s->field), decl, s->field, NULL_TREE); if (TREE_THIS_VOLATILE (s->field)) TREE_THIS_VOLATILE (comp) = 1; SET_DECL_VALUE_EXPR (var_decl, comp); DECL_HAS_VALUE_EXPR_P (var_decl) = 1; GFC_DECL_COMMON_OR_EQUIV (var_decl) = 1; if (s->sym->attr.assign) { gfc_allocate_lang_decl (var_decl); GFC_DECL_ASSIGN (var_decl) = 1; GFC_DECL_STRING_LEN (var_decl) = GFC_DECL_STRING_LEN (s->field); GFC_DECL_ASSIGN_ADDR (var_decl) = GFC_DECL_ASSIGN_ADDR (s->field); } s->sym->backend_decl = var_decl; next_s = s->next; free (s); } } /* Given a symbol, find it in the current segment list. Returns NULL if not found. */ static segment_info * find_segment_info (gfc_symbol *symbol) { segment_info *n; for (n = current_segment; n; n = n->next) { if (n->sym == symbol) return n; } return NULL; } /* Given an expression node, make sure it is a constant integer and return the mpz_t value. */ static mpz_t * get_mpz (gfc_expr *e) { if (e->expr_type != EXPR_CONSTANT) gfc_internal_error ("get_mpz(): Not an integer constant"); return &e->value.integer; } /* Given an array specification and an array reference, figure out the array element number (zero based). Bounds and elements are guaranteed to be constants. If something goes wrong we generate an error and return zero. */ static HOST_WIDE_INT element_number (gfc_array_ref *ar) { mpz_t multiplier, offset, extent, n; gfc_array_spec *as; HOST_WIDE_INT i, rank; as = ar->as; rank = as->rank; mpz_init_set_ui (multiplier, 1); mpz_init_set_ui (offset, 0); mpz_init (extent); mpz_init (n); for (i = 0; i < rank; i++) { if (ar->dimen_type[i] != DIMEN_ELEMENT) gfc_internal_error ("element_number(): Bad dimension type"); if (as && as->lower[i]) mpz_sub (n, *get_mpz (ar->start[i]), *get_mpz (as->lower[i])); else mpz_sub_ui (n, *get_mpz (ar->start[i]), 1); mpz_mul (n, n, multiplier); mpz_add (offset, offset, n); if (as && as->upper[i] && as->lower[i]) { mpz_sub (extent, *get_mpz (as->upper[i]), *get_mpz (as->lower[i])); mpz_add_ui (extent, extent, 1); } else mpz_set_ui (extent, 0); if (mpz_sgn (extent) < 0) mpz_set_ui (extent, 0); mpz_mul (multiplier, multiplier, extent); } i = mpz_get_ui (offset); mpz_clear (multiplier); mpz_clear (offset); mpz_clear (extent); mpz_clear (n); return i; } /* Given a single element of an equivalence list, figure out the offset from the base symbol. For simple variables or full arrays, this is simply zero. For an array element we have to calculate the array element number and multiply by the element size. For a substring we have to calculate the further reference. */ static HOST_WIDE_INT calculate_offset (gfc_expr *e) { HOST_WIDE_INT n, element_size, offset; gfc_typespec *element_type; gfc_ref *reference; offset = 0; element_type = &e->symtree->n.sym->ts; for (reference = e->ref; reference; reference = reference->next) switch (reference->type) { case REF_ARRAY: switch (reference->u.ar.type) { case AR_FULL: break; case AR_ELEMENT: n = element_number (&reference->u.ar); if (element_type->type == BT_CHARACTER) gfc_conv_const_charlen (element_type->u.cl); element_size = int_size_in_bytes (gfc_typenode_for_spec (element_type)); offset += n * element_size; break; default: gfc_error ("Bad array reference at %L", &e->where); } break; case REF_SUBSTRING: if (reference->u.ss.start != NULL) offset += mpz_get_ui (*get_mpz (reference->u.ss.start)) - 1; break; default: gfc_error ("Illegal reference type at %L as EQUIVALENCE object", &e->where); } return offset; } /* Add a new segment_info structure to the current segment. eq1 is already in the list, eq2 is not. */ static void new_condition (segment_info *v, gfc_equiv *eq1, gfc_equiv *eq2) { HOST_WIDE_INT offset1, offset2; segment_info *a; offset1 = calculate_offset (eq1->expr); offset2 = calculate_offset (eq2->expr); a = get_segment_info (eq2->expr->symtree->n.sym, v->offset + offset1 - offset2); current_segment = add_segments (current_segment, a); } /* Given two equivalence structures that are both already in the list, make sure that this new condition is not violated, generating an error if it is. */ static void confirm_condition (segment_info *s1, gfc_equiv *eq1, segment_info *s2, gfc_equiv *eq2) { HOST_WIDE_INT offset1, offset2; offset1 = calculate_offset (eq1->expr); offset2 = calculate_offset (eq2->expr); if (s1->offset + offset1 != s2->offset + offset2) gfc_error ("Inconsistent equivalence rules involving %qs at %L and " "%qs at %L", s1->sym->name, &s1->sym->declared_at, s2->sym->name, &s2->sym->declared_at); } /* Process a new equivalence condition. eq1 is know to be in segment f. If eq2 is also present then confirm that the condition holds. Otherwise add a new variable to the segment list. */ static void add_condition (segment_info *f, gfc_equiv *eq1, gfc_equiv *eq2) { segment_info *n; n = find_segment_info (eq2->expr->symtree->n.sym); if (n == NULL) new_condition (f, eq1, eq2); else confirm_condition (f, eq1, n, eq2); } static void accumulate_equivalence_attributes (symbol_attribute *dummy_symbol, gfc_equiv *e) { symbol_attribute attr = e->expr->symtree->n.sym->attr; dummy_symbol->dummy |= attr.dummy; dummy_symbol->pointer |= attr.pointer; dummy_symbol->target |= attr.target; dummy_symbol->external |= attr.external; dummy_symbol->intrinsic |= attr.intrinsic; dummy_symbol->allocatable |= attr.allocatable; dummy_symbol->elemental |= attr.elemental; dummy_symbol->recursive |= attr.recursive; dummy_symbol->in_common |= attr.in_common; dummy_symbol->result |= attr.result; dummy_symbol->in_namelist |= attr.in_namelist; dummy_symbol->optional |= attr.optional; dummy_symbol->entry |= attr.entry; dummy_symbol->function |= attr.function; dummy_symbol->subroutine |= attr.subroutine; dummy_symbol->dimension |= attr.dimension; dummy_symbol->in_equivalence |= attr.in_equivalence; dummy_symbol->use_assoc |= attr.use_assoc; dummy_symbol->cray_pointer |= attr.cray_pointer; dummy_symbol->cray_pointee |= attr.cray_pointee; dummy_symbol->data |= attr.data; dummy_symbol->value |= attr.value; dummy_symbol->volatile_ |= attr.volatile_; dummy_symbol->is_protected |= attr.is_protected; dummy_symbol->is_bind_c |= attr.is_bind_c; dummy_symbol->procedure |= attr.procedure; dummy_symbol->proc_pointer |= attr.proc_pointer; dummy_symbol->abstract |= attr.abstract; dummy_symbol->asynchronous |= attr.asynchronous; dummy_symbol->codimension |= attr.codimension; dummy_symbol->contiguous |= attr.contiguous; dummy_symbol->generic |= attr.generic; dummy_symbol->automatic |= attr.automatic; dummy_symbol->threadprivate |= attr.threadprivate; dummy_symbol->omp_declare_target |= attr.omp_declare_target; dummy_symbol->omp_declare_target_link |= attr.omp_declare_target_link; dummy_symbol->oacc_declare_copyin |= attr.oacc_declare_copyin; dummy_symbol->oacc_declare_create |= attr.oacc_declare_create; dummy_symbol->oacc_declare_deviceptr |= attr.oacc_declare_deviceptr; dummy_symbol->oacc_declare_device_resident |= attr.oacc_declare_device_resident; /* Not strictly correct, but probably close enough. */ if (attr.save > dummy_symbol->save) dummy_symbol->save = attr.save; if (attr.access > dummy_symbol->access) dummy_symbol->access = attr.access; } /* Given a segment element, search through the equivalence lists for unused conditions that involve the symbol. Add these rules to the segment. */ static bool find_equivalence (segment_info *n) { gfc_equiv *e1, *e2, *eq; bool found; found = FALSE; for (e1 = n->sym->ns->equiv; e1; e1 = e1->next) { eq = NULL; /* Search the equivalence list, including the root (first) element for the symbol that owns the segment. */ symbol_attribute dummy_symbol; memset (&dummy_symbol, 0, sizeof (dummy_symbol)); for (e2 = e1; e2; e2 = e2->eq) { accumulate_equivalence_attributes (&dummy_symbol, e2); if (!e2->used && e2->expr->symtree->n.sym == n->sym) { eq = e2; break; } } gfc_check_conflict (&dummy_symbol, e1->expr->symtree->name, &e1->expr->where); /* Go to the next root element. */ if (eq == NULL) continue; eq->used = 1; /* Now traverse the equivalence list matching the offsets. */ for (e2 = e1; e2; e2 = e2->eq) { if (!e2->used && e2 != eq) { add_condition (n, eq, e2); e2->used = 1; found = TRUE; } } } return found; } /* Add all symbols equivalenced within a segment. We need to scan the segment list multiple times to include indirect equivalences. Since a new segment_info can inserted at the beginning of the segment list, depending on its offset, we have to force a final pass through the loop by demanding that completion sees a pass with no matches; i.e., all symbols with equiv_built set and no new equivalences found. */ static void add_equivalences (bool *saw_equiv) { segment_info *f; bool more = TRUE; while (more) { more = FALSE; for (f = current_segment; f; f = f->next) { if (!f->sym->equiv_built) { f->sym->equiv_built = 1; bool seen_one = find_equivalence (f); if (seen_one) { *saw_equiv = true; more = true; } } } } /* Add a copy of this segment list to the namespace. */ copy_equiv_list_to_ns (current_segment); } /* Returns the offset necessary to properly align the current equivalence. Sets *palign to the required alignment. */ static HOST_WIDE_INT align_segment (unsigned HOST_WIDE_INT *palign) { segment_info *s; unsigned HOST_WIDE_INT offset; unsigned HOST_WIDE_INT max_align; unsigned HOST_WIDE_INT this_align; unsigned HOST_WIDE_INT this_offset; max_align = 1; offset = 0; for (s = current_segment; s; s = s->next) { this_align = TYPE_ALIGN_UNIT (s->field); if (s->offset & (this_align - 1)) { /* Field is misaligned. */ this_offset = this_align - ((s->offset + offset) & (this_align - 1)); if (this_offset & (max_align - 1)) { /* Aligning this field would misalign a previous field. */ gfc_error ("The equivalence set for variable %qs " "declared at %L violates alignment requirements", s->sym->name, &s->sym->declared_at); } offset += this_offset; } max_align = this_align; } if (palign) *palign = max_align; return offset; } /* Adjust segment offsets by the given amount. */ static void apply_segment_offset (segment_info *s, HOST_WIDE_INT offset) { for (; s; s = s->next) s->offset += offset; } /* Lay out a symbol in a common block. If the symbol has already been seen then check the location is consistent. Otherwise create segments for that symbol and all the symbols equivalenced with it. */ /* Translate a single common block. */ static void translate_common (gfc_common_head *common, gfc_symbol *var_list) { gfc_symbol *sym; segment_info *s; segment_info *common_segment; HOST_WIDE_INT offset; HOST_WIDE_INT current_offset; unsigned HOST_WIDE_INT align; bool saw_equiv; common_segment = NULL; offset = 0; current_offset = 0; align = 1; saw_equiv = false; /* Add symbols to the segment. */ for (sym = var_list; sym; sym = sym->common_next) { current_segment = common_segment; s = find_segment_info (sym); /* Symbol has already been added via an equivalence. Multiple use associations of the same common block result in equiv_built being set but no information about the symbol in the segment. */ if (s && sym->equiv_built) { /* Ensure the current location is properly aligned. */ align = TYPE_ALIGN_UNIT (s->field); current_offset = (current_offset + align - 1) &~ (align - 1); /* Verify that it ended up where we expect it. */ if (s->offset != current_offset) { gfc_error ("Equivalence for %qs does not match ordering of " "COMMON %qs at %L", sym->name, common->name, &common->where); } } else { /* A symbol we haven't seen before. */ s = current_segment = get_segment_info (sym, current_offset); /* Add all objects directly or indirectly equivalenced with this symbol. */ add_equivalences (&saw_equiv); if (current_segment->offset < 0) gfc_error ("The equivalence set for %qs cause an invalid " "extension to COMMON %qs at %L", sym->name, common->name, &common->where); if (flag_align_commons) offset = align_segment (&align); if (offset) { /* The required offset conflicts with previous alignment requirements. Insert padding immediately before this segment. */ if (warn_align_commons) { if (strcmp (common->name, BLANK_COMMON_NAME)) gfc_warning (OPT_Walign_commons, "Padding of %d bytes required before %qs in " "COMMON %qs at %L; reorder elements or use " "%<-fno-align-commons%>", (int)offset, s->sym->name, common->name, &common->where); else gfc_warning (OPT_Walign_commons, "Padding of %d bytes required before %qs in " "COMMON at %L; reorder elements or use " "%<-fno-align-commons%>", (int)offset, s->sym->name, &common->where); } } /* Apply the offset to the new segments. */ apply_segment_offset (current_segment, offset); current_offset += offset; /* Add the new segments to the common block. */ common_segment = add_segments (common_segment, current_segment); } /* The offset of the next common variable. */ current_offset += s->length; } if (common_segment == NULL) { gfc_error ("COMMON %qs at %L does not exist", common->name, &common->where); return; } if (common_segment->offset != 0 && warn_align_commons) { if (strcmp (common->name, BLANK_COMMON_NAME)) gfc_warning (OPT_Walign_commons, "COMMON %qs at %L requires %d bytes of padding; " "reorder elements or use %<-fno-align-commons%>", common->name, &common->where, (int)common_segment->offset); else gfc_warning (OPT_Walign_commons, "COMMON at %L requires %d bytes of padding; " "reorder elements or use %<-fno-align-commons%>", &common->where, (int)common_segment->offset); } create_common (common, common_segment, saw_equiv); } /* Create a new block for each merged equivalence list. */ static void finish_equivalences (gfc_namespace *ns) { gfc_equiv *z, *y; gfc_symbol *sym; gfc_common_head * c; HOST_WIDE_INT offset; unsigned HOST_WIDE_INT align; bool dummy; for (z = ns->equiv; z; z = z->next) for (y = z->eq; y; y = y->eq) { if (y->used) continue; sym = z->expr->symtree->n.sym; current_segment = get_segment_info (sym, 0); /* All objects directly or indirectly equivalenced with this symbol. */ add_equivalences (&dummy); /* Align the block. */ offset = align_segment (&align); /* Ensure all offsets are positive. */ offset -= current_segment->offset & ~(align - 1); apply_segment_offset (current_segment, offset); /* Create the decl. If this is a module equivalence, it has a unique name, pointed to by z->module. This is written to a gfc_common_header to push create_common into using build_common_decl, so that the equivalence appears as an external symbol. Otherwise, a local declaration is built using build_equiv_decl. */ if (z->module) { c = gfc_get_common_head (); /* We've lost the real location, so use the location of the enclosing procedure. If we're in a BLOCK DATA block, then use the location in the sym_root. */ if (ns->proc_name) c->where = ns->proc_name->declared_at; else if (ns->is_block_data) c->where = ns->sym_root->n.sym->declared_at; size_t len = strlen (z->module); gcc_assert (len < sizeof (c->name)); memcpy (c->name, z->module, len); c->name[len] = '\0'; } else c = NULL; create_common (c, current_segment, true); break; } } /* Work function for translating a named common block. */ static void named_common (gfc_symtree *st) { translate_common (st->n.common, st->n.common->head); } /* Translate the common blocks in a namespace. Unlike other variables, these have to be created before code, because the backend_decl depends on the rest of the common block. */ void gfc_trans_common (gfc_namespace *ns) { gfc_common_head *c; /* Translate the blank common block. */ if (ns->blank_common.head != NULL) { c = gfc_get_common_head (); c->where = ns->blank_common.head->common_head->where; strcpy (c->name, BLANK_COMMON_NAME); translate_common (c, ns->blank_common.head); } /* Translate all named common blocks. */ gfc_traverse_symtree (ns->common_root, named_common); /* Translate local equivalence. */ finish_equivalences (ns); /* Commit the newly created symbols for common blocks and module equivalences. */ gfc_commit_symbols (); }