169 lines
3.4 KiB
C
169 lines
3.4 KiB
C
/* L A B E L H A N D L I N G */
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#include <alloc.h>
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#include <em.h>
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#include "LLlex.h"
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#include "def.h"
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#include "idf.h"
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#include "main.h"
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#include "node.h"
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#include "scope.h"
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#include "type.h"
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DeclLabel(nd)
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struct node *nd;
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{
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struct def *df;
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if( !(df = define(nd->nd_IDF, CurrentScope, D_LABEL)) ) {
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node_error(nd, "label %s redeclared", nd->nd_IDF->id_text);
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}
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else {
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df->lab_no = ++text_label;
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nd->nd_def = df;
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}
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}
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chk_labels(Slevel)
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{
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register struct node *labnd = BlockScope->sc_lablist;
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register struct def *df;
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while( labnd ) {
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df = labnd->nd_def;
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if( Slevel == 1 ) {
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if( !df->lab_level )
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if( df->lab_next )
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/* jump to undefined label */
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error("jump to undefined label %s",
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df->df_idf->id_text);
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else
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warning(
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"label %s declared but never defined",
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df->df_idf->id_text);
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}
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else if( df->lab_level == Slevel )
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df->lab_level = -1;
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else if( !df->lab_level ) {
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struct lab *plab = df->lab_next;
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while( plab ) {
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if( plab->lb_level > 1 )
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plab->lb_level--;
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plab = plab->lb_next;
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}
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}
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labnd = labnd->nd_next;
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}
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}
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TstLabel(nd, Slevel)
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register struct node *nd;
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{
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register struct def *df;
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df = lookfor(nd, CurrVis, 0);
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if( df->df_kind == D_ERROR ) {
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node_error(nd, "label %s not declared", df->df_idf->id_text);
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df->df_kind = D_LABEL;
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nd->nd_def = df;
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nd->nd_next = BlockScope->sc_lablist;
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BlockScope->sc_lablist = nd;
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}
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else
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FreeNode(nd);
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df->df_flags = D_USED;
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if( !df->lab_level ) {
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/* forward jump */
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register struct lab *labelptr;
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labelptr = new_lab();
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labelptr->lb_next = df->lab_next;
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df->lab_next = labelptr;
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if( df->df_scope == BlockScope ) {
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/* local jump */
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labelptr->lb_level = Slevel;
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CodeLabel(df, 1);
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}
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else {
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/* non-local jump, only permitted to
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outermost level (ISO 6.8.1 Note 2)
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*/
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labelptr->lb_level = 1;
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CodeLabel(df, 0);
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}
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}
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else if( df->lab_level == -1 || df->lab_level > Slevel )
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node_error(nd, "illegal jump to label %s", df->df_idf->id_text);
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else
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CodeLabel(df, 1);
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}
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DefLabel(nd, Slevel)
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register struct node *nd;
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{
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register struct def *df;
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if( !(df = lookup(nd->nd_IDF, BlockScope, D_INUSE)) ) {
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node_error(nd, "label %s must be declared in same block"
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, nd->nd_IDF->id_text);
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df = define(nd->nd_IDF, BlockScope, D_LABEL);
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nd->nd_def = df;
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df->lab_no = ++text_label;
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nd->nd_next = BlockScope->sc_lablist;
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BlockScope->sc_lablist = nd;
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}
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else FreeNode(nd);
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df->df_flags |= D_SET;
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if( df->lab_level)
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node_error(nd, "label %s already defined", nd->nd_IDF->id_text);
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else {
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register struct lab *labelptr;
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df->lab_level = Slevel;
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labelptr = df->lab_next;
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while( labelptr ) {
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if( labelptr->lb_level < Slevel ) {
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node_error(nd, "illegal jump to label %s",
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nd->nd_IDF->id_text);
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return;
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}
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labelptr = labelptr->lb_next;
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}
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C_df_ilb(df->lab_no);
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}
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}
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CodeLabel(df, local)
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register struct def *df;
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{
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if( err_occurred ) return;
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if( local )
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C_bra(df->lab_no);
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else {
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/* non-local jump */
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int level = df->df_scope->sc_level;
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if( !df->lab_descr ) {
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/* generate label for goto descriptor */
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df->lab_descr = ++data_label;
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C_ina_dlb(data_label);
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}
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/* perform the jump */
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C_lae_dlb(df->lab_descr, (arith) 0);
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/* LB of target procedure */
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if( level > 0 )
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C_lxl((arith) proclevel - level);
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else
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C_zer(pointer_size);
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C_cal("_gto");
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C_asp( 2 * pointer_size);
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}
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}
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