/* Routines for manipulation of expression nodes. Copyright (C) 2000, 2001, 2002, 2003 Free Software Foundation, Inc. Contributed by Andy Vaught This file is part of GNU G95. GNU G95 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 2, or (at your option) any later version. GNU G95 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 GNU G95; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "config.h" #include #include #include #include "gfortran.h" #include "arith.h" #include "match.h" /* Get a new expr node. */ gfc_expr * gfc_get_expr (void) { gfc_expr *e; e = gfc_getmem (sizeof (gfc_expr)); gfc_clear_ts (&e->ts); e->op1 = NULL; e->op2 = NULL; e->shape = NULL; e->ref = NULL; e->symtree = NULL; e->uop = NULL; return e; } /* Free an argument list and everything below it. */ void gfc_free_actual_arglist (gfc_actual_arglist * a1) { gfc_actual_arglist *a2; while (a1) { a2 = a1->next; gfc_free_expr (a1->expr); gfc_free (a1); a1 = a2; } } /* Copy an arglist structure and all of the arguments. */ gfc_actual_arglist * gfc_copy_actual_arglist (gfc_actual_arglist * p) { gfc_actual_arglist *head, *tail, *new; head = tail = NULL; for (; p; p = p->next) { new = gfc_get_actual_arglist (); *new = *p; new->expr = gfc_copy_expr (p->expr); new->next = NULL; if (head == NULL) head = new; else tail->next = new; tail = new; } return head; } /* Free a list of reference structures. */ void gfc_free_ref_list (gfc_ref * p) { gfc_ref *q; int i; for (; p; p = q) { q = p->next; switch (p->type) { case REF_ARRAY: for (i = 0; i < GFC_MAX_DIMENSIONS; i++) { gfc_free_expr (p->u.ar.start[i]); gfc_free_expr (p->u.ar.end[i]); gfc_free_expr (p->u.ar.stride[i]); } break; case REF_SUBSTRING: gfc_free_expr (p->u.ss.start); gfc_free_expr (p->u.ss.end); break; case REF_COMPONENT: break; } gfc_free (p); } } /* Workhorse function for gfc_free_expr() that frees everything beneath an expression node, but not the node itself. This is useful when we want to simplify a node and replace it with something else or the expression node belongs to another structure. */ static void free_expr0 (gfc_expr * e) { int n; switch (e->expr_type) { case EXPR_CONSTANT: switch (e->ts.type) { case BT_INTEGER: mpz_clear (e->value.integer); break; case BT_REAL: mpf_clear (e->value.real); break; case BT_CHARACTER: gfc_free (e->value.character.string); break; case BT_COMPLEX: mpf_clear (e->value.complex.r); mpf_clear (e->value.complex.i); break; default: break; } break; case EXPR_OP: if (e->op1 != NULL) gfc_free_expr (e->op1); if (e->op2 != NULL) gfc_free_expr (e->op2); break; case EXPR_FUNCTION: gfc_free_actual_arglist (e->value.function.actual); break; case EXPR_VARIABLE: break; case EXPR_ARRAY: case EXPR_STRUCTURE: gfc_free_constructor (e->value.constructor); break; case EXPR_SUBSTRING: gfc_free (e->value.character.string); break; case EXPR_NULL: break; default: gfc_internal_error ("free_expr0(): Bad expr type"); } /* Free a shape array. */ if (e->shape != NULL) { for (n = 0; n < e->rank; n++) mpz_clear (e->shape[n]); gfc_free (e->shape); } gfc_free_ref_list (e->ref); memset (e, '\0', sizeof (gfc_expr)); } /* Free an expression node and everything beneath it. */ void gfc_free_expr (gfc_expr * e) { if (e == NULL) return; free_expr0 (e); gfc_free (e); } /* Graft the *src expression onto the *dest subexpression. */ void gfc_replace_expr (gfc_expr * dest, gfc_expr * src) { free_expr0 (dest); *dest = *src; gfc_free (src); } /* Try to extract an integer constant from the passed expression node. Returns an error message or NULL if the result is set. It is tempting to generate an error and return SUCCESS or FAILURE, but failure is OK for some callers. */ const char * gfc_extract_int (gfc_expr * expr, int *result) { if (expr->expr_type != EXPR_CONSTANT) return "Constant expression required at %C"; if (expr->ts.type != BT_INTEGER) return "Integer expression required at %C"; if ((mpz_cmp_si (expr->value.integer, INT_MAX) > 0) || (mpz_cmp_si (expr->value.integer, INT_MIN) < 0)) { return "Integer value too large in expression at %C"; } *result = (int) mpz_get_si (expr->value.integer); return NULL; } /* Recursively copy a list of reference structures. */ static gfc_ref * copy_ref (gfc_ref * src) { gfc_array_ref *ar; gfc_ref *dest; if (src == NULL) return NULL; dest = gfc_get_ref (); dest->type = src->type; switch (src->type) { case REF_ARRAY: ar = gfc_copy_array_ref (&src->u.ar); dest->u.ar = *ar; gfc_free (ar); break; case REF_COMPONENT: dest->u.c = src->u.c; break; case REF_SUBSTRING: dest->u.ss = src->u.ss; dest->u.ss.start = gfc_copy_expr (src->u.ss.start); dest->u.ss.end = gfc_copy_expr (src->u.ss.end); break; } dest->next = copy_ref (src->next); return dest; } /* Copy a shape array. */ mpz_t * gfc_copy_shape (mpz_t * shape, int rank) { mpz_t *new_shape; int n; if (shape == NULL) return NULL; new_shape = gfc_get_shape (rank); for (n = 0; n < rank; n++) mpz_init_set (new_shape[n], shape[n]); return new_shape; } /* Given an expression pointer, return a copy of the expression. This subroutine is recursive. */ gfc_expr * gfc_copy_expr (gfc_expr * p) { gfc_expr *q; char *s; if (p == NULL) return NULL; q = gfc_get_expr (); *q = *p; switch (q->expr_type) { case EXPR_SUBSTRING: s = gfc_getmem (p->value.character.length + 1); q->value.character.string = s; memcpy (s, p->value.character.string, p->value.character.length + 1); q->op1 = gfc_copy_expr (p->op1); q->op2 = gfc_copy_expr (p->op2); break; case EXPR_CONSTANT: switch (q->ts.type) { case BT_INTEGER: mpz_init_set (q->value.integer, p->value.integer); break; case BT_REAL: mpf_init_set (q->value.real, p->value.real); break; case BT_COMPLEX: mpf_init_set (q->value.complex.r, p->value.complex.r); mpf_init_set (q->value.complex.i, p->value.complex.i); break; case BT_CHARACTER: s = gfc_getmem (p->value.character.length + 1); q->value.character.string = s; memcpy (s, p->value.character.string, p->value.character.length + 1); break; case BT_LOGICAL: case BT_DERIVED: break; /* Already done */ case BT_PROCEDURE: case BT_UNKNOWN: gfc_internal_error ("gfc_copy_expr(): Bad expr node"); /* Not reached */ } break; case EXPR_OP: switch (q->operator) { case INTRINSIC_NOT: case INTRINSIC_UPLUS: case INTRINSIC_UMINUS: q->op1 = gfc_copy_expr (p->op1); break; default: /* Binary operators */ q->op1 = gfc_copy_expr (p->op1); q->op2 = gfc_copy_expr (p->op2); break; } break; case EXPR_FUNCTION: q->value.function.actual = gfc_copy_actual_arglist (p->value.function.actual); break; case EXPR_STRUCTURE: case EXPR_ARRAY: q->value.constructor = gfc_copy_constructor (p->value.constructor); break; case EXPR_VARIABLE: case EXPR_NULL: break; } q->shape = gfc_copy_shape (p->shape, p->rank); q->ref = copy_ref (p->ref); return q; } /* Return the maximum kind of two expressions. In general, higher kind numbers mean more precision for numeric types. */ int gfc_kind_max (gfc_expr * e1, gfc_expr * e2) { return (e1->ts.kind > e2->ts.kind) ? e1->ts.kind : e2->ts.kind; } /* Returns nonzero if the type is numeric, zero otherwise. */ static int numeric_type (bt type) { return type == BT_COMPLEX || type == BT_REAL || type == BT_INTEGER; } /* Returns nonzero if the typespec is a numeric type, zero otherwise. */ int gfc_numeric_ts (gfc_typespec * ts) { return numeric_type (ts->type); } /* Returns an expression node that is an integer constant. */ gfc_expr * gfc_int_expr (int i) { gfc_expr *p; p = gfc_get_expr (); p->expr_type = EXPR_CONSTANT; p->ts.type = BT_INTEGER; p->ts.kind = gfc_default_integer_kind (); p->where = *gfc_current_locus (); mpz_init_set_si (p->value.integer, i); return p; } /* Returns an expression node that is a logical constant. */ gfc_expr * gfc_logical_expr (int i, locus * where) { gfc_expr *p; p = gfc_get_expr (); p->expr_type = EXPR_CONSTANT; p->ts.type = BT_LOGICAL; p->ts.kind = gfc_default_logical_kind (); if (where == NULL) where = gfc_current_locus (); p->where = *where; p->value.logical = i; return p; } /* Return an expression node with an optional argument list attached. A variable number of gfc_expr pointers are strung together in an argument list with a NULL pointer terminating the list. */ gfc_expr * gfc_build_conversion (gfc_expr * e) { gfc_expr *p; p = gfc_get_expr (); p->expr_type = EXPR_FUNCTION; p->symtree = NULL; p->value.function.actual = NULL; p->value.function.actual = gfc_get_actual_arglist (); p->value.function.actual->expr = e; return p; } /* Given an expression node with some sort of numeric binary expression, insert type conversions required to make the operands have the same type. The exception is that the operands of an exponential don't have to have the same type. If possible, the base is promoted to the type of the exponent. For example, 1**2.3 becomes 1.0**2.3, but 1.0**2 stays as it is. */ void gfc_type_convert_binary (gfc_expr * e) { gfc_expr *op1, *op2; op1 = e->op1; op2 = e->op2; if (op1->ts.type == BT_UNKNOWN || op2->ts.type == BT_UNKNOWN) { gfc_clear_ts (&e->ts); return; } /* Kind conversions of same type. */ if (op1->ts.type == op2->ts.type) { if (op1->ts.kind == op2->ts.kind) { /* No type conversions. */ e->ts = op1->ts; goto done; } if (op1->ts.kind > op2->ts.kind) gfc_convert_type (op2, &op1->ts, 2); else gfc_convert_type (op1, &op2->ts, 2); e->ts = op1->ts; goto done; } /* Integer combined with real or complex. */ if (op2->ts.type == BT_INTEGER) { e->ts = op1->ts; /* Special cose for ** operator. */ if (e->operator == INTRINSIC_POWER) goto done; gfc_convert_type (e->op2, &e->ts, 2); goto done; } if (op1->ts.type == BT_INTEGER) { e->ts = op2->ts; gfc_convert_type (e->op1, &e->ts, 2); goto done; } /* Real combined with complex. */ e->ts.type = BT_COMPLEX; if (op1->ts.kind > op2->ts.kind) e->ts.kind = op1->ts.kind; else e->ts.kind = op2->ts.kind; if (op1->ts.type != BT_COMPLEX || op1->ts.kind != e->ts.kind) gfc_convert_type (e->op1, &e->ts, 2); if (op2->ts.type != BT_COMPLEX || op2->ts.kind != e->ts.kind) gfc_convert_type (e->op2, &e->ts, 2); done: return; } /* Function to determine if an expression is constant or not. This function expects that the expression has already been simplified. */ int gfc_is_constant_expr (gfc_expr * e) { gfc_constructor *c; gfc_actual_arglist *arg; int rv; if (e == NULL) return 1; switch (e->expr_type) { case EXPR_OP: rv = (gfc_is_constant_expr (e->op1) && (e->op2 == NULL || gfc_is_constant_expr (e->op2))); break; case EXPR_VARIABLE: rv = 0; break; case EXPR_FUNCTION: /* Call to intrinsic with at least one argument. */ rv = 0; if (e->value.function.isym && e->value.function.actual) { for (arg = e->value.function.actual; arg; arg = arg->next) { if (!gfc_is_constant_expr (arg->expr)) break; } if (arg == NULL) rv = 1; } break; case EXPR_CONSTANT: case EXPR_NULL: rv = 1; break; case EXPR_SUBSTRING: rv = gfc_is_constant_expr (e->op1) && gfc_is_constant_expr (e->op2); break; case EXPR_STRUCTURE: rv = 0; for (c = e->value.constructor; c; c = c->next) if (!gfc_is_constant_expr (c->expr)) break; if (c == NULL) rv = 1; break; case EXPR_ARRAY: rv = gfc_constant_ac (e); break; default: gfc_internal_error ("gfc_is_constant_expr(): Unknown expression type"); } return rv; } /* Try to collapse intrinsic expressions. */ static try simplify_intrinsic_op (gfc_expr * p, int type) { gfc_expr *op1, *op2, *result; if (p->operator == INTRINSIC_USER) return SUCCESS; op1 = p->op1; op2 = p->op2; if (gfc_simplify_expr (op1, type) == FAILURE) return FAILURE; if (gfc_simplify_expr (op2, type) == FAILURE) return FAILURE; if (!gfc_is_constant_expr (op1) || (op2 != NULL && !gfc_is_constant_expr (op2))) return SUCCESS; /* Rip p apart */ p->op1 = NULL; p->op2 = NULL; switch (p->operator) { case INTRINSIC_UPLUS: result = gfc_uplus (op1); break; case INTRINSIC_UMINUS: result = gfc_uminus (op1); break; case INTRINSIC_PLUS: result = gfc_add (op1, op2); break; case INTRINSIC_MINUS: result = gfc_subtract (op1, op2); break; case INTRINSIC_TIMES: result = gfc_multiply (op1, op2); break; case INTRINSIC_DIVIDE: result = gfc_divide (op1, op2); break; case INTRINSIC_POWER: result = gfc_power (op1, op2); break; case INTRINSIC_CONCAT: result = gfc_concat (op1, op2); break; case INTRINSIC_EQ: result = gfc_eq (op1, op2); break; case INTRINSIC_NE: result = gfc_ne (op1, op2); break; case INTRINSIC_GT: result = gfc_gt (op1, op2); break; case INTRINSIC_GE: result = gfc_ge (op1, op2); break; case INTRINSIC_LT: result = gfc_lt (op1, op2); break; case INTRINSIC_LE: result = gfc_le (op1, op2); break; case INTRINSIC_NOT: result = gfc_not (op1); break; case INTRINSIC_AND: result = gfc_and (op1, op2); break; case INTRINSIC_OR: result = gfc_or (op1, op2); break; case INTRINSIC_EQV: result = gfc_eqv (op1, op2); break; case INTRINSIC_NEQV: result = gfc_neqv (op1, op2); break; default: gfc_internal_error ("simplify_intrinsic_op(): Bad operator"); } if (result == NULL) { gfc_free_expr (op1); gfc_free_expr (op2); return FAILURE; } gfc_replace_expr (p, result); return SUCCESS; } /* Subroutine to simplify constructor expressions. Mutually recursive with gfc_simplify_expr(). */ static try simplify_constructor (gfc_constructor * c, int type) { for (; c; c = c->next) { if (c->iterator && (gfc_simplify_expr (c->iterator->start, type) == FAILURE || gfc_simplify_expr (c->iterator->end, type) == FAILURE || gfc_simplify_expr (c->iterator->step, type) == FAILURE)) return FAILURE; if (c->expr && gfc_simplify_expr (c->expr, type) == FAILURE) return FAILURE; } return SUCCESS; } /* Pull a single array element out of an array constructor. */ static gfc_constructor * find_array_element (gfc_constructor * cons, gfc_array_ref * ar) { unsigned long nelemen; int i; mpz_t delta; mpz_t offset; mpz_init_set_ui (offset, 0); mpz_init (delta); for (i = 0; i < ar->dimen; i++) { if (ar->start[i]->expr_type != EXPR_CONSTANT) { cons = NULL; break; } mpz_sub (delta, ar->start[i]->value.integer, ar->as->lower[i]->value.integer); mpz_add (offset, offset, delta); } if (cons) { if (mpz_fits_ulong_p (offset)) { for (nelemen = mpz_get_ui (offset); nelemen > 0; nelemen--) { if (cons->iterator) { cons = NULL; break; } cons = cons->next; } } else cons = NULL; } mpz_clear (delta); mpz_clear (offset); return cons; } /* Find a component of a structure constructor. */ static gfc_constructor * find_component_ref (gfc_constructor * cons, gfc_ref * ref) { gfc_component *comp; gfc_component *pick; comp = ref->u.c.sym->components; pick = ref->u.c.component; while (comp != pick) { comp = comp->next; cons = cons->next; } return cons; } /* Replace an expression with the contents of a constructor, removing the subobject reference in the process. */ static void remove_subobject_ref (gfc_expr * p, gfc_constructor * cons) { gfc_expr *e; e = cons->expr; cons->expr = NULL; e->ref = p->ref->next; p->ref->next = NULL; gfc_replace_expr (p, e); } /* Simplify a subobject reference of a constructor. This occurs when parameter variable values are substituted. */ static try simplify_const_ref (gfc_expr * p) { gfc_constructor *cons; while (p->ref) { switch (p->ref->type) { case REF_ARRAY: switch (p->ref->u.ar.type) { case AR_ELEMENT: cons = find_array_element (p->value.constructor, &p->ref->u.ar); if (!cons) return SUCCESS; remove_subobject_ref (p, cons); break; case AR_FULL: if (p->ref->next != NULL) { /* TODO: Simplify array subobject references. */ return SUCCESS; } gfc_free_ref_list (p->ref); p->ref = NULL; break; default: /* TODO: Simplify array subsections. */ return SUCCESS; } break; case REF_COMPONENT: cons = find_component_ref (p->value.constructor, p->ref); remove_subobject_ref (p, cons); break; case REF_SUBSTRING: /* TODO: Constant substrings. */ return SUCCESS; } } return SUCCESS; } /* Simplify a chain of references. */ static try simplify_ref_chain (gfc_ref * ref, int type) { int n; for (; ref; ref = ref->next) { switch (ref->type) { case REF_ARRAY: for (n = 0; n < ref->u.ar.dimen; n++) { if (gfc_simplify_expr (ref->u.ar.start[n], type) == FAILURE) return FAILURE; if (gfc_simplify_expr (ref->u.ar.end[n], type) == FAILURE) return FAILURE; if (gfc_simplify_expr (ref->u.ar.stride[n], type) == FAILURE) return FAILURE; } break; case REF_SUBSTRING: if (gfc_simplify_expr (ref->u.ss.start, type) == FAILURE) return FAILURE; if (gfc_simplify_expr (ref->u.ss.end, type) == FAILURE) return FAILURE; break; default: break; } } return SUCCESS; } /* Try to substitute the value of a parameter variable. */ static try simplify_parameter_variable (gfc_expr * p, int type) { gfc_expr *e; try t; e = gfc_copy_expr (p->symtree->n.sym->value); if (p->ref) e->ref = copy_ref (p->ref); t = gfc_simplify_expr (e, type); /* Only use the simplification if it eliminated all subobject references. */ if (t == SUCCESS && ! e->ref) gfc_replace_expr (p, e); else gfc_free_expr (e); return t; } /* Given an expression, simplify it by collapsing constant expressions. Most simplification takes place when the expression tree is being constructed. If an intrinsic function is simplified at some point, we get called again to collapse the result against other constants. We work by recursively simplifying expression nodes, simplifying intrinsic functions where possible, which can lead to further constant collapsing. If an operator has constant operand(s), we rip the expression apart, and rebuild it, hoping that it becomes something simpler. The expression type is defined for: 0 Basic expression parsing 1 Simplifying array constructors -- will substitute iterator values. Returns FAILURE on error, SUCCESS otherwise. NOTE: Will return SUCCESS even if the expression can not be simplified. */ try gfc_simplify_expr (gfc_expr * p, int type) { gfc_actual_arglist *ap; if (p == NULL) return SUCCESS; switch (p->expr_type) { case EXPR_CONSTANT: case EXPR_NULL: break; case EXPR_FUNCTION: for (ap = p->value.function.actual; ap; ap = ap->next) if (gfc_simplify_expr (ap->expr, type) == FAILURE) return FAILURE; if (p->value.function.isym != NULL && gfc_intrinsic_func_interface (p, 1) == MATCH_ERROR) return FAILURE; break; case EXPR_SUBSTRING: if (gfc_simplify_expr (p->op1, type) == FAILURE || gfc_simplify_expr (p->op2, type) == FAILURE) return FAILURE; /* TODO: evaluate constant substrings. */ break; case EXPR_OP: if (simplify_intrinsic_op (p, type) == FAILURE) return FAILURE; break; case EXPR_VARIABLE: /* Only substitute array parameter variables if we are in an initialization expression, or we want a subsection. */ if (p->symtree->n.sym->attr.flavor == FL_PARAMETER && (gfc_init_expr || p->ref || p->symtree->n.sym->value->expr_type != EXPR_ARRAY)) { if (simplify_parameter_variable (p, type) == FAILURE) return FAILURE; break; } if (type == 1) { gfc_simplify_iterator_var (p); } /* Simplify subcomponent references. */ if (simplify_ref_chain (p->ref, type) == FAILURE) return FAILURE; break; case EXPR_STRUCTURE: case EXPR_ARRAY: if (simplify_ref_chain (p->ref, type) == FAILURE) return FAILURE; if (simplify_constructor (p->value.constructor, type) == FAILURE) return FAILURE; if (p->expr_type == EXPR_ARRAY) gfc_expand_constructor (p); if (simplify_const_ref (p) == FAILURE) return FAILURE; break; } return SUCCESS; } /* Returns the type of an expression with the exception that iterator variables are automatically integers no matter what else they may be declared as. */ static bt et0 (gfc_expr * e) { if (e->expr_type == EXPR_VARIABLE && gfc_check_iter_variable (e) == SUCCESS) return BT_INTEGER; return e->ts.type; } /* Check an intrinsic arithmetic operation to see if it is consistent with some type of expression. */ static try check_init_expr (gfc_expr *); static try check_intrinsic_op (gfc_expr * e, try (*check_function) (gfc_expr *)) { if ((*check_function) (e->op1) == FAILURE) return FAILURE; switch (e->operator) { case INTRINSIC_UPLUS: case INTRINSIC_UMINUS: if (!numeric_type (et0 (e->op1))) goto not_numeric; break; case INTRINSIC_EQ: case INTRINSIC_NE: case INTRINSIC_GT: case INTRINSIC_GE: case INTRINSIC_LT: case INTRINSIC_LE: case INTRINSIC_PLUS: case INTRINSIC_MINUS: case INTRINSIC_TIMES: case INTRINSIC_DIVIDE: case INTRINSIC_POWER: if ((*check_function) (e->op2) == FAILURE) return FAILURE; if (!numeric_type (et0 (e->op1)) || !numeric_type (et0 (e->op2))) goto not_numeric; if (e->operator != INTRINSIC_POWER) break; if (check_function == check_init_expr && et0 (e->op2) != BT_INTEGER) { gfc_error ("Exponent at %L must be INTEGER for an initialization " "expression", &e->op2->where); return FAILURE; } break; case INTRINSIC_CONCAT: if ((*check_function) (e->op2) == FAILURE) return FAILURE; if (et0 (e->op1) != BT_CHARACTER || et0 (e->op2) != BT_CHARACTER) { gfc_error ("Concatenation operator in expression at %L " "must have two CHARACTER operands", &e->op1->where); return FAILURE; } if (e->op1->ts.kind != e->op2->ts.kind) { gfc_error ("Concat operator at %L must concatenate strings of the " "same kind", &e->where); return FAILURE; } break; case INTRINSIC_NOT: if (et0 (e->op1) != BT_LOGICAL) { gfc_error (".NOT. operator in expression at %L must have a LOGICAL " "operand", &e->op1->where); return FAILURE; } break; case INTRINSIC_AND: case INTRINSIC_OR: case INTRINSIC_EQV: case INTRINSIC_NEQV: if ((*check_function) (e->op2) == FAILURE) return FAILURE; if (et0 (e->op1) != BT_LOGICAL || et0 (e->op2) != BT_LOGICAL) { gfc_error ("LOGICAL operands are required in expression at %L", &e->where); return FAILURE; } break; default: gfc_error ("Only intrinsic operators can be used in expression at %L", &e->where); return FAILURE; } return SUCCESS; not_numeric: gfc_error ("Numeric operands are required in expression at %L", &e->where); return FAILURE; } /* Certain inquiry functions are specifically allowed to have variable arguments, which is an exception to the normal requirement that an initialization function have initialization arguments. We head off this problem here. */ static try check_inquiry (gfc_expr * e) { const char *name; /* FIXME: This should be moved into the intrinsic definitions, to eliminate this ugly hack. */ static const char * const inquiry_function[] = { "digits", "epsilon", "huge", "kind", "maxexponent", "minexponent", "precision", "radix", "range", "tiny", "bit_size", "size", "shape", "lbound", "ubound", NULL }; int i; /* These functions must have exactly one argument. */ if (e->value.function.actual == NULL || e->value.function.actual->next != NULL) return FAILURE; if (e->value.function.name != NULL && e->value.function.name[0] != '\0') return FAILURE; name = e->symtree->n.sym->name; for (i = 0; inquiry_function[i]; i++) if (strcmp (inquiry_function[i], name) == 0) break; if (inquiry_function[i] == NULL) return FAILURE; e = e->value.function.actual->expr; if (e == NULL || e->expr_type != EXPR_VARIABLE) return FAILURE; /* At this point we have a numeric inquiry function with a variable argument. The type of the variable might be undefined, but we need it now, because the arguments of these functions are allowed to be undefined. */ if (e->ts.type == BT_UNKNOWN) { if (e->symtree->n.sym->ts.type == BT_UNKNOWN && gfc_set_default_type (e->symtree->n.sym, 0, gfc_current_ns) == FAILURE) return FAILURE; e->ts = e->symtree->n.sym->ts; } return SUCCESS; } /* Verify that an expression is an initialization expression. A side effect is that the expression tree is reduced to a single constant node if all goes well. This would normally happen when the expression is constructed but function references are assumed to be intrinsics in the context of initialization expressions. If FAILURE is returned an error message has been generated. */ static try check_init_expr (gfc_expr * e) { gfc_actual_arglist *ap; match m; try t; if (e == NULL) return SUCCESS; switch (e->expr_type) { case EXPR_OP: t = check_intrinsic_op (e, check_init_expr); if (t == SUCCESS) t = gfc_simplify_expr (e, 0); break; case EXPR_FUNCTION: t = SUCCESS; if (check_inquiry (e) != SUCCESS) { t = SUCCESS; for (ap = e->value.function.actual; ap; ap = ap->next) if (check_init_expr (ap->expr) == FAILURE) { t = FAILURE; break; } } if (t == SUCCESS) { m = gfc_intrinsic_func_interface (e, 0); if (m == MATCH_NO) gfc_error ("Function '%s' in initialization expression at %L " "must be an intrinsic function", e->symtree->n.sym->name, &e->where); if (m != MATCH_YES) t = FAILURE; } break; case EXPR_VARIABLE: t = SUCCESS; if (gfc_check_iter_variable (e) == SUCCESS) break; if (e->symtree->n.sym->attr.flavor == FL_PARAMETER) { t = simplify_parameter_variable (e, 0); break; } gfc_error ("Variable '%s' at %L cannot appear in an initialization " "expression", e->symtree->n.sym->name, &e->where); t = FAILURE; break; case EXPR_CONSTANT: case EXPR_NULL: t = SUCCESS; break; case EXPR_SUBSTRING: t = check_init_expr (e->op1); if (t == FAILURE) break; t = check_init_expr (e->op2); if (t == SUCCESS) t = gfc_simplify_expr (e, 0); break; case EXPR_STRUCTURE: t = gfc_check_constructor (e, check_init_expr); break; case EXPR_ARRAY: t = gfc_check_constructor (e, check_init_expr); if (t == FAILURE) break; t = gfc_expand_constructor (e); if (t == FAILURE) break; t = gfc_check_constructor_type (e); break; default: gfc_internal_error ("check_init_expr(): Unknown expression type"); } return t; } /* Match an initialization expression. We work by first matching an expression, then reducing it to a constant. */ match gfc_match_init_expr (gfc_expr ** result) { gfc_expr *expr; match m; try t; m = gfc_match_expr (&expr); if (m != MATCH_YES) return m; gfc_init_expr = 1; t = gfc_resolve_expr (expr); if (t == SUCCESS) t = check_init_expr (expr); gfc_init_expr = 0; if (t == FAILURE) { gfc_free_expr (expr); return MATCH_ERROR; } if (expr->expr_type == EXPR_ARRAY && (gfc_check_constructor_type (expr) == FAILURE || gfc_expand_constructor (expr) == FAILURE)) { gfc_free_expr (expr); return MATCH_ERROR; } if (!gfc_is_constant_expr (expr)) gfc_internal_error ("Initialization expression didn't reduce %C"); *result = expr; return MATCH_YES; } static try check_restricted (gfc_expr *); /* Given an actual argument list, test to see that each argument is a restricted expression and optionally if the expression type is integer or character. */ static try restricted_args (gfc_actual_arglist * a, int check_type) { bt type; for (; a; a = a->next) { if (check_restricted (a->expr) == FAILURE) return FAILURE; if (!check_type) continue; type = a->expr->ts.type; if (type != BT_CHARACTER && type != BT_INTEGER) { gfc_error ("Function argument at %L must be of type INTEGER or CHARACTER", &a->expr->where); return FAILURE; } } return SUCCESS; } /************* Restricted/specification expressions *************/ /* Make sure a non-intrinsic function is a specification function. */ static try external_spec_function (gfc_expr * e) { gfc_symbol *f; f = e->value.function.esym; if (f->attr.proc == PROC_ST_FUNCTION) { gfc_error ("Specification function '%s' at %L cannot be a statement " "function", f->name, &e->where); return FAILURE; } if (f->attr.proc == PROC_INTERNAL) { gfc_error ("Specification function '%s' at %L cannot be an internal " "function", f->name, &e->where); return FAILURE; } if (!f->attr.pure) { gfc_error ("Specification function '%s' at %L must be PURE", f->name, &e->where); return FAILURE; } if (f->attr.recursive) { gfc_error ("Specification function '%s' at %L cannot be RECURSIVE", f->name, &e->where); return FAILURE; } return restricted_args (e->value.function.actual, 0); } /* Check to see that a function reference to an intrinsic is a restricted expression. Some functions required by the standard are omitted because references to them have already been simplified. Strictly speaking, a lot of these checks are redundant with other checks. If a function is indeed a particular intrinsic, then the type of its argument have already been checked and passed. */ static try restricted_intrinsic (gfc_expr * e) { gfc_intrinsic_sym *sym; static struct { const char *name; int case_number; } const *cp, cases[] = { {"repeat", 0}, {"reshape", 0}, {"selected_int_kind", 0}, {"selected_real_kind", 0}, {"transfer", 0}, {"trim", 0}, {"null", 1}, {"lbound", 2}, {"shape", 2}, {"size", 2}, {"ubound", 2}, /* bit_size() has already been reduced */ {"len", 0}, /* kind() has already been reduced */ /* Numeric inquiry functions have been reduced */ { NULL, 0} }; try t; sym = e->value.function.isym; if (!sym) return FAILURE; if (sym->elemental) return restricted_args (e->value.function.actual, 1); for (cp = cases; cp->name; cp++) if (strcmp (cp->name, sym->name) == 0) break; if (cp->name == NULL) { gfc_error ("Intrinsic function '%s' at %L is not a restricted function", sym->name, &e->where); return FAILURE; } switch (cp->case_number) { case 0: /* Functions that are restricted if they have character/integer args. */ t = restricted_args (e->value.function.actual, 1); break; case 1: /* NULL() */ t = SUCCESS; break; case 2: /* Functions that could be checking the bounds of an assumed-size array. */ t = SUCCESS; /* TODO: implement checks from 7.1.6.2 (10) */ break; default: gfc_internal_error ("restricted_intrinsic(): Bad case"); } return t; } /* Verify that an expression is a restricted expression. Like its cousin check_init_expr(), an error message is generated if we return FAILURE. */ static try check_restricted (gfc_expr * e) { gfc_symbol *sym; try t; if (e == NULL) return SUCCESS; switch (e->expr_type) { case EXPR_OP: t = check_intrinsic_op (e, check_restricted); if (t == SUCCESS) t = gfc_simplify_expr (e, 0); break; case EXPR_FUNCTION: t = e->value.function.esym ? external_spec_function (e) : restricted_intrinsic (e); break; case EXPR_VARIABLE: sym = e->symtree->n.sym; t = FAILURE; if (sym->attr.optional) { gfc_error ("Dummy argument '%s' at %L cannot be OPTIONAL", sym->name, &e->where); break; } if (sym->attr.intent == INTENT_OUT) { gfc_error ("Dummy argument '%s' at %L cannot be INTENT(OUT)", sym->name, &e->where); break; } if (sym->attr.in_common || sym->attr.use_assoc || sym->attr.dummy || sym->ns != gfc_current_ns || (sym->ns->proc_name != NULL && sym->ns->proc_name->attr.flavor == FL_MODULE)) { t = SUCCESS; break; } gfc_error ("Variable '%s' cannot appear in the expression at %L", sym->name, &e->where); break; case EXPR_NULL: case EXPR_CONSTANT: t = SUCCESS; break; case EXPR_SUBSTRING: t = gfc_specification_expr (e->op1); if (t == FAILURE) break; t = gfc_specification_expr (e->op2); if (t == SUCCESS) t = gfc_simplify_expr (e, 0); break; case EXPR_STRUCTURE: t = gfc_check_constructor (e, check_restricted); break; case EXPR_ARRAY: t = gfc_check_constructor (e, check_restricted); break; default: gfc_internal_error ("check_restricted(): Unknown expression type"); } return t; } /* Check to see that an expression is a specification expression. If we return FAILURE, an error has been generated. */ try gfc_specification_expr (gfc_expr * e) { if (e->ts.type != BT_INTEGER) { gfc_error ("Expression at %L must be of INTEGER type", &e->where); return FAILURE; } if (e->rank != 0) { gfc_error ("Expression at %L must be scalar", &e->where); return FAILURE; } if (gfc_simplify_expr (e, 0) == FAILURE) return FAILURE; return check_restricted (e); } /************** Expression conformance checks. *************/ /* Given two expressions, make sure that the arrays are conformable. */ try gfc_check_conformance (const char *optype, gfc_expr * op1, gfc_expr * op2) { int op1_flag, op2_flag, d; mpz_t op1_size, op2_size; try t; if (op1->rank == 0 || op2->rank == 0) return SUCCESS; if (op1->rank != op2->rank) { gfc_error ("Incompatible ranks in %s at %L", optype, &op1->where); return FAILURE; } t = SUCCESS; for (d = 0; d < op1->rank; d++) { op1_flag = gfc_array_dimen_size (op1, d, &op1_size) == SUCCESS; op2_flag = gfc_array_dimen_size (op2, d, &op2_size) == SUCCESS; if (op1_flag && op2_flag && mpz_cmp (op1_size, op2_size) != 0) { gfc_error ("%s at %L has different shape on dimension %d (%d/%d)", optype, &op1->where, d + 1, (int) mpz_get_si (op1_size), (int) mpz_get_si (op2_size)); t = FAILURE; } if (op1_flag) mpz_clear (op1_size); if (op2_flag) mpz_clear (op2_size); if (t == FAILURE) return FAILURE; } return SUCCESS; } /* Given an assignable expression and an arbitrary expression, make sure that the assignment can take place. */ try gfc_check_assign (gfc_expr * lvalue, gfc_expr * rvalue, int conform) { gfc_symbol *sym; sym = lvalue->symtree->n.sym; if (sym->attr.intent == INTENT_IN) { gfc_error ("Can't assign to INTENT(IN) variable '%s' at %L", sym->name, &lvalue->where); return FAILURE; } if (rvalue->rank != 0 && lvalue->rank != rvalue->rank) { gfc_error ("Incompatible ranks in assignment at %L", &lvalue->where); return FAILURE; } if (lvalue->ts.type == BT_UNKNOWN) { gfc_error ("Variable type is UNKNOWN in assignment at %L", &lvalue->where); return FAILURE; } /* Check size of array assignments. */ if (lvalue->rank != 0 && rvalue->rank != 0 && gfc_check_conformance ("Array assignment", lvalue, rvalue) != SUCCESS) return FAILURE; if (gfc_compare_types (&lvalue->ts, &rvalue->ts)) return SUCCESS; if (!conform) { if (gfc_numeric_ts (&lvalue->ts) && gfc_numeric_ts (&rvalue->ts)) return SUCCESS; gfc_error ("Incompatible types in assignment at %L, %s to %s", &rvalue->where, gfc_typename (&rvalue->ts), gfc_typename (&lvalue->ts)); return FAILURE; } return gfc_convert_type (rvalue, &lvalue->ts, 1); } /* Check that a pointer assignment is OK. We first check lvalue, and we only check rvalue if it's not an assignment to NULL() or a NULLIFY statement. */ try gfc_check_pointer_assign (gfc_expr * lvalue, gfc_expr * rvalue) { symbol_attribute attr; int is_pure; if (lvalue->symtree->n.sym->ts.type == BT_UNKNOWN) { gfc_error ("Pointer assignment target is not a POINTER at %L", &lvalue->where); return FAILURE; } attr = gfc_variable_attr (lvalue, NULL); if (!attr.pointer) { gfc_error ("Pointer assignment to non-POINTER at %L", &lvalue->where); return FAILURE; } is_pure = gfc_pure (NULL); if (is_pure && gfc_impure_variable (lvalue->symtree->n.sym)) { gfc_error ("Bad pointer object in PURE procedure at %L", &lvalue->where); return FAILURE; } /* If rvalue is a NULL() or NULLIFY, we're done. Otherwise the type, kind, etc for lvalue and rvalue must match, and rvalue must be a pure variable if we're in a pure function. */ if (rvalue->expr_type != EXPR_NULL) { if (!gfc_compare_types (&lvalue->ts, &rvalue->ts)) { gfc_error ("Different types in pointer assignment at %L", &lvalue->where); return FAILURE; } if (lvalue->ts.kind != rvalue->ts.kind) { gfc_error ("Different kind type parameters in pointer assignment at %L", &lvalue->where); return FAILURE; } attr = gfc_expr_attr (rvalue); if (!attr.target && !attr.pointer) { gfc_error ("Pointer assignment target is neither TARGET nor POINTER at " "%L", &rvalue->where); return FAILURE; } if (is_pure && gfc_impure_variable (rvalue->symtree->n.sym)) { gfc_error ("Bad target in pointer assignment in PURE procedure at %L", &rvalue->where); } } return SUCCESS; } /* Relative of gfc_check_assign() except that the lvalue is a single symbol. */ try gfc_check_assign_symbol (gfc_symbol * sym, gfc_expr * rvalue) { gfc_expr lvalue; try r; memset (&lvalue, '\0', sizeof (gfc_expr)); lvalue.expr_type = EXPR_VARIABLE; lvalue.ts = sym->ts; if (sym->as) lvalue.rank = sym->as->rank; lvalue.symtree = (gfc_symtree *)gfc_getmem (sizeof (gfc_symtree)); lvalue.symtree->n.sym = sym; lvalue.where = sym->declared_at; r = gfc_check_assign (&lvalue, rvalue, 1); gfc_free (lvalue.symtree); return r; }