393 lines
8.4 KiB
C
393 lines
8.4 KiB
C
/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*
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* Author: Ceriel J.H. Jacobs
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*/
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/* D E F I N I T I O N M E C H A N I S M */
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/* $Header$ */
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#include "debug.h"
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#include <alloc.h>
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#include <em_arith.h>
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#include <em_label.h>
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#include <em_code.h>
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#include <assert.h>
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#include "LLlex.h"
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#include "main.h"
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#include "def.h"
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#include "type.h"
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#include "idf.h"
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#include "scope.h"
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#include "node.h"
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#include "Lpars.h"
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#include "warning.h"
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extern char *sprint();
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STATIC
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internal(c)
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register char *c;
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{
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if (options['x']) {
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C_exp(c);
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}
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else C_inp(c);
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}
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STATIC
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DefInFront(df)
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register t_def *df;
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{
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/* Put definition "df" in front of the list of definitions
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in its scope.
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This is neccessary because in some cases the order in this
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list is important.
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*/
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register t_def *df1 = df->df_scope->sc_def;
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if (df1 != df) {
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/* Definition "df" is not in front of the list
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*/
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while (df1) {
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/* Find definition "df"
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*/
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if (df1->df_nextinscope == df) {
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/* It already was in the list. Remove it
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*/
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df1->df_nextinscope = df->df_nextinscope;
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break;
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}
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df1 = df1->df_nextinscope;
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}
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/* Now put it in front
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*/
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df->df_nextinscope = df->df_scope->sc_def;
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df->df_scope->sc_def = df;
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}
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}
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t_def *
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MkDef(id, scope, kind)
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register t_idf *id;
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register t_scope *scope;
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{
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/* Create a new definition structure in scope "scope", with
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id "id" and kind "kind".
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*/
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register t_def *df;
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df = new_def();
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df->df_idf = id;
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df->df_scope = scope;
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df->df_kind = kind;
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df->df_next = id->id_def;
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id->id_def = df;
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if (kind == D_ERROR || kind == D_FORWARD) df->df_type = error_type;
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if (kind & (D_TYPE|D_PROCEDURE|D_CONST)) {
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df->df_flags = D_DEFINED;
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}
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/* enter the definition in the list of definitions in this scope
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*/
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df->df_nextinscope = scope->sc_def;
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scope->sc_def = df;
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return df;
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}
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t_def *
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define(id, scope, kind)
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register t_idf *id;
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register t_scope *scope;
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int kind;
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{
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/* Declare an identifier in a scope, but first check if it
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already has been defined.
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If so, then check for the cases in which this is legal,
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and otherwise give an error message.
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*/
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register t_def *df;
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DO_DEBUG(options['S'], print("define %s, %x\n", id->id_text, kind));
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df = lookup(id, scope, D_IMPORT, 0);
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if ( /* Already in this scope */
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df
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) {
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switch(df->df_kind) {
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case D_INUSE:
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if (kind != D_INUSE && kind != D_ERROR) {
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error("identifier \"%s\" already used; may not be redefined in this scope", df->df_idf->id_text);
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df->df_kind = D_ERROR;
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break;
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}
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return df;
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case D_HIDDEN:
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/* An opaque type. We may now have found the
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definition of this type.
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*/
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if (kind == D_TYPE && !DefinitionModule) {
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df->df_kind = D_TYPE;
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return df;
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}
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break;
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case D_FORWMODULE:
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/* A forward reference to a module. We may have found
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another one, or we may have found the definition
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for this module.
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*/
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if (kind & (D_FORWMODULE|D_FORWARD)) {
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return df;
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}
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if (kind == D_MODULE) {
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FreeNode(df->for_node);
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df->mod_vis = df->for_vis;
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df->df_kind = kind;
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DefInFront(df);
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return df;
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}
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break;
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case D_TYPE:
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if (kind == D_FORWTYPE) return df;
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break;
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case D_FORWTYPE:
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if (kind & (D_FORWTYPE|D_TYPE)) return df;
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error("identifier \"%s\" must be a type", id->id_text);
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df->df_kind = D_ERROR;
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break;
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case D_FORWARD:
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/* A forward reference, for which we may now have
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found a definition.
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*/
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if (! (kind & (D_FORWARD | D_FORWMODULE))) {
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FreeNode(df->for_node);
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}
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df->df_kind = D_ERROR; /* avoiding error message */
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break;
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}
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if (kind != D_ERROR && df->df_kind != D_ERROR) {
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/* Avoid spurious error messages
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*/
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error("identifier \"%s\" already declared",
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id->id_text);
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}
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if (df->df_scope == scope || df->df_kind == D_ERROR) {
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df->df_kind = kind;
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if (kind & (D_TYPE|D_PROCEDURE|D_CONST)) {
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df->df_flags = D_DEFINED;
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}
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return df;
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}
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}
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return MkDef(id, scope, kind);
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}
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end_definition_list(pdf)
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register t_def **pdf;
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{
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/* Remove all imports from a definition module. This is
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neccesary because the implementation module might import
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them again.
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Also, mark all other definitions "QUALIFIED EXPORT".
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*/
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register t_def *df;
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while (df = *pdf) {
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if (df->df_kind & D_IMPORTED) {
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if (! (df->df_flags & D_USED)) {
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warning(W_ORDINARY, "identifier \"%s\" imported but not used", df->df_idf->id_text);
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}
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RemoveFromIdList(df);
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*pdf = df->df_nextinscope;
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free_def(df);
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}
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else {
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df->df_flags |= D_QEXPORTED;
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pdf = &(df->df_nextinscope);
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}
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}
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}
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RemoveFromIdList(df)
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register t_def *df;
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{
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/* Remove definition "df" from the definition list
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*/
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register t_idf *id = df->df_idf;
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register t_def *df1;
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if ((df1 = id->id_def) == df) id->id_def = df->df_next;
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else {
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while (df1->df_next != df) {
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assert(df1->df_next != 0);
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df1 = df1->df_next;
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}
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df1->df_next = df->df_next;
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}
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}
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t_def *
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DeclProc(type, id)
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register t_idf *id;
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{
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/* A procedure is declared, either in a definition or a program
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module. Create a def structure for it (if neccessary).
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Also create a name for it.
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*/
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register t_def *df;
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register t_scope *scope;
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static int nmcount;
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char buf[256];
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assert(type & (D_PROCEDURE | D_PROCHEAD));
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if (type == D_PROCHEAD) {
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/* In a definition module
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*/
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df = define(id, CurrentScope, type);
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df->for_node = dot2leaf(Name);
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df->df_flags |= D_USED | D_DEFINED;
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if (CurrentScope->sc_definedby->df_flags & D_FOREIGN) {
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df->prc_name = id->id_text;
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}
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else {
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sprint(buf,"%s_%s",CurrentScope->sc_name,id->id_text);
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df->prc_name = Salloc(buf, (unsigned) (strlen(buf)+1));
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}
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if (CurrVis == Defined->mod_vis) {
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/* The current module will define this routine.
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make sure the name is exported.
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*/
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C_exp(df->prc_name);
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}
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}
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else {
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df = lookup(id, CurrentScope, D_IMPORTED, 0);
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if (df && df->df_kind == D_PROCHEAD) {
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/* C_exp already generated when we saw the definition
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in the definition module
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*/
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DefInFront(df);
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}
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else {
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df = define(id, CurrentScope, type);
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sprint(buf,"_%d_%s",++nmcount,id->id_text);
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df->prc_name = Salloc(buf, (unsigned)(strlen(buf)+1));
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internal(buf);
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df->df_flags |= D_DEFINED;
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}
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open_scope(OPENSCOPE);
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scope = CurrentScope;
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scope->sc_name = df->prc_name;
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scope->sc_definedby = df;
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}
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df->prc_vis = CurrVis;
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return df;
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}
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EndProc(df, id)
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register t_def *df;
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t_idf *id;
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{
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/* The end of a procedure declaration.
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Check that the closing identifier matches the name of the
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procedure, close the scope, and check that a function
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procedure has at least one RETURN statement.
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*/
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extern int return_occurred;
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match_id(id, df->df_idf);
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close_scope(SC_CHKFORW|SC_REVERSE);
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if (! return_occurred && ResultType(df->df_type)) {
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error("function procedure %s does not return a value",
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df->df_idf->id_text);
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}
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}
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t_def *
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DefineLocalModule(id)
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t_idf *id;
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{
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/* Create a definition for a local module. Also give it
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a name to be used for code generation.
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*/
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register t_def *df = define(id, CurrentScope, D_MODULE);
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register t_scope *sc;
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static int modulecount = 0;
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char buf[256];
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extern int proclevel;
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sprint(buf, "_%d%s_", ++modulecount, id->id_text);
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if (!df->mod_vis) {
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/* We never saw the name of this module before. Create a
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scope for it.
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*/
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open_scope(CLOSEDSCOPE);
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df->mod_vis = CurrVis;
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}
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CurrVis = df->mod_vis;
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sc = CurrentScope;
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sc->sc_level = proclevel;
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sc->sc_definedby = df;
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sc->sc_name = Salloc(buf, (unsigned) (strlen(buf) + 1));
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/* Create a type for it
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*/
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df->df_type = standard_type(T_RECORD, 1, (arith) 0);
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df->df_type->rec_scope = sc;
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/* Generate code that indicates that the initialization procedure
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for this module is local.
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*/
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internal(buf);
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return df;
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}
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CheckWithDef(df, tp)
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register t_def *df;
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t_type *tp;
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{
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/* Check the header of a procedure declaration against a
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possible earlier definition in the definition module.
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*/
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if (df->df_kind == D_PROCHEAD &&
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df->df_type &&
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df->df_type != error_type) {
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/* We already saw a definition of this type
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in the definition module.
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*/
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if (!TstProcEquiv(tp, df->df_type)) {
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error("inconsistent procedure declaration for \"%s\"",
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df->df_idf->id_text);
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}
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FreeType(df->df_type);
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df->df_kind = D_PROCEDURE;
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}
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df->df_type = tp;
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}
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#ifdef DEBUG
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PrDef(df)
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register t_def *df;
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{
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print("n: %s, k: %d\n", df->df_idf->id_text, df->df_kind);
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}
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#endif DEBUG
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