Initial revision

1988-10-26 15:21:11 +00:00
parent a7a80689bf
commit 01252cb592
60 changed files with 11297 additions and 0 deletions
--- a/lang/pc/comp/label.c
+++ b/lang/pc/comp/label.c
@@ -0,0 +1,165 @@
+/*	L A B E L   H A N D L I N G	*/
+
+#include	<alloc.h>
+#include	<em.h>
+
+#include	"LLlex.h"
+#include	"def.h"
+#include	"idf.h"
+#include	"main.h"
+#include	"node.h"
+#include	"scope.h"
+#include	"type.h"
+
+
+DeclLabel(nd)
+	struct node *nd;
+{
+	struct def *df;
+
+	if( !(df = define(nd->nd_IDF, CurrentScope, D_LABEL)) )
+		node_error(nd, "label %s redeclared", nd->nd_IDF->id_text);
+	else	{
+		df->lab_no = ++text_label;
+		nd->nd_def = df;
+	}
+}
+
+chk_labels(Slevel)
+{
+	register struct node *labnd = BlockScope->sc_lablist;
+	register struct def *df;
+
+	while( labnd )	{
+		df = labnd->nd_def;
+		if( Slevel == 1 )	{
+			if( !df->lab_level )
+				if( df->lab_next )
+				/* jump to undefined label */
+					error("jump to undefined label %s",
+							df->df_idf->id_text);
+				else
+					warning(
+					  "label %s declared but never defined",
+							df->df_idf->id_text);
+		}
+		else if( df->lab_level == Slevel )
+			df->lab_level = -1;
+		else if( !df->lab_level )	{
+			struct lab *plab = df->lab_next;
+
+			while( plab )	{
+				if( plab->lb_level > 1 )
+					plab->lb_level--;
+				plab = plab->lb_next;
+			}
+		}
+		labnd = labnd->nd_next;
+	}
+}
+
+TstLabel(nd, Slevel)
+	register struct node *nd;
+{
+	register struct def *df;
+
+	df = lookfor(nd, CurrVis, 0);
+	if( df->df_kind == D_ERROR )	{
+		node_error(nd, "label %s not declared", df->df_idf->id_text);
+		df->df_kind = D_LABEL;
+		nd->nd_def = df;
+		nd->nd_next = BlockScope->sc_lablist;
+		BlockScope->sc_lablist = nd;
+	}
+	else
+		FreeNode(nd);
+
+	if( !df->lab_level )	{
+		/* forward jump */
+		register struct lab *labelptr;
+
+		labelptr = new_lab();
+		labelptr->lb_next = df->lab_next;
+		df->lab_next = labelptr;
+		if( df->df_scope == BlockScope )	{
+			/* local jump */
+			labelptr->lb_level = Slevel;
+			CodeLabel(df, 1);
+		}
+		else	{
+			/* non-local jump, only permitted to
+			   outermost level (ISO 6.8.1 Note 2)
+			*/
+			labelptr->lb_level = 1;
+			CodeLabel(df, 0);
+		}
+	}
+	else if( df->lab_level == -1 || df->lab_level > Slevel )
+		node_error(nd, "illegal jump to label %s", df->df_idf->id_text);
+	else
+		CodeLabel(df, 1);
+}
+
+DefLabel(nd, Slevel)
+	register struct node *nd;
+{
+	register struct def *df;
+
+	if( !(df = lookup(nd->nd_IDF, BlockScope)) )	{
+		node_error(nd, "label %s must be declared in same block"
+							, nd->nd_IDF->id_text);
+		df = define(nd->nd_IDF, BlockScope, D_LABEL);
+		nd->nd_def = df;
+		df->lab_no = ++text_label;
+		nd->nd_next = BlockScope->sc_lablist;
+		BlockScope->sc_lablist = nd;
+	}
+	else FreeNode(nd);
+
+	if( df->lab_level)
+		node_error(nd, "label %s already defined", nd->nd_IDF->id_text);
+	else	{
+		register struct lab *labelptr;
+
+		df->lab_level = Slevel;
+		labelptr = df->lab_next;
+		while( labelptr )	{
+			if( labelptr->lb_level < Slevel )	{
+				node_error(nd, "illegal jump to label %s",
+							nd->nd_IDF->id_text);
+				return;
+			}
+			labelptr = labelptr->lb_next;
+		}
+		C_df_ilb(df->lab_no);
+	}
+}
+
+CodeLabel(df, local)
+	register struct def *df;
+{
+	if( err_occurred ) return;
+
+	if( local )
+		C_bra(df->lab_no);
+	else	{
+		/* non-local jump */
+		int level = df->df_scope->sc_level;
+
+		if( !df->lab_descr )	{
+			/* generate label for goto descriptor */
+			df->lab_descr = ++data_label;
+			C_ina_dlb(data_label);
+		}
+		/* perform the jump */
+		C_lae_dlb(df->lab_descr, (arith) 0);
+
+		/* LB of target procedure */
+		if( level > 0 )
+			C_lxl((arith) proclevel - level);
+		else
+			C_zer(pointer_size);
+		C_cal("_gto");
+		C_asp( 2 * pointer_size);
+	}
+}