BSD 3 development

Work on file usr/src/cmd/pi/lab.c

Co-Authored-By: Bill Joy <wnj@ucbvax.Berkeley.EDU>
Co-Authored-By: Ken Thompson <ken@research.uucp>
Synthesized-from: 3bsd

diff --git a/usr/src/cmd/pi/lab.c b/usr/src/cmd/pi/lab.c
new file mode 100644 (file)
index 0000000..6427abc
--- /dev/null
+++ b/usr/src/cmd/pi/lab.c
@@ -0,0 +1,133 @@
+/* Copyright (c) 1979 Regents of the University of California */
+#
+/*
+ * pi - Pascal interpreter code translator
+ *
+ * Charles Haley, Bill Joy UCB
+ * Version 1.2 November 1978
+ */
+
+#include "whoami"
+#include "0.h"
+#include "tree.h"
+#include "opcode.h"
+
+/*
+ * Label enters the definitions
+ * of the label declaration part
+ * into the namelist.
+ */
+label(r, l)
+       int *r, l;
+{
+#ifndef PI0
+       register *ll;
+       register struct nl *p, *lp;
+
+       lp = NIL;
+#else
+       send(REVLAB, r);
+#endif
+       line = l;
+#ifndef PI1
+       if (parts & (CPRT|TPRT|VPRT))
+               error("Label declarations must precede const, type and var declarations");
+       if (parts & LPRT)
+               error("All labels must be declared in one label part");
+       parts |= LPRT;
+#endif
+#ifndef PI0
+       for (ll = r; ll != NIL; ll = ll[2]) {
+               l = getlab();
+               p = enter(defnl(ll[1], LABEL, 0, l));
+               /*
+                * Get the label for the eventual target
+                */
+               p->value[1] = getlab();
+               p->chain = lp;
+               p->nl_flags |= (NFORWD|NMOD);
+               p->value[NL_GOLEV] = NOTYET;
+               p->entloc = l;
+               lp = p;
+               /*
+                * This operator is between
+                * the bodies of two procedures
+                * and provides a target for
+                * gotos for this label via TRA.
+                */
+               putlab(l);
+               put2(O_GOTO | cbn<<9, p->value[1]);
+       }
+       gotos[cbn] = lp;
+#      ifdef PTREE
+           {
+               pPointer        Labels = LabelDCopy( r );
+
+               pDEF( PorFHeader[ nesting ] ).PorFLabels = Labels;
+           }
+#      endif
+#endif
+}
+
+#ifndef PI0
+/*
+ * Gotoop is called when
+ * we get a statement "goto label"
+ * and generates the needed tra.
+ */
+gotoop(s)
+       char *s;
+{
+       register struct nl *p;
+
+       gocnt++;
+       p = lookup(s);
+       if (p == NIL)
+               return (NIL);
+       put2(O_TRA4, p->entloc);
+       if (bn == cbn)
+               if (p->nl_flags & NFORWD) {
+                       if (p->value[NL_GOLEV] == NOTYET) {
+                               p->value[NL_GOLEV] = level;
+                               p->value[NL_GOLINE] = line;
+                       }
+               } else
+                       if (p->value[NL_GOLEV] == DEAD) {
+                               recovered();
+                               error("Goto %s is into a structured statement", p->symbol);
+                       }
+}
+
+/*
+ * Labeled is called when a label
+ * definition is encountered, and
+ * marks that it has been found and
+ * patches the associated GOTO generated
+ * by gotoop.
+ */
+labeled(s)
+       char *s;
+{
+       register struct nl *p;
+
+       p = lookup(s);
+       if (p == NIL)
+               return (NIL);
+       if (bn != cbn) {
+               error("Label %s not defined in correct block", s);
+               return;
+       }
+       if ((p->nl_flags & NFORWD) == 0) {
+               error("Label %s redefined", s);
+               return;
+       }
+       p->nl_flags &= ~NFORWD;
+       patch4(p->entloc);
+       if (p->value[NL_GOLEV] != NOTYET)
+               if (p->value[NL_GOLEV] < level) {
+                       recovered();
+                       error("Goto %s from line %d is into a structured statement", s, p->value[NL_GOLINE]);
+               }
+       p->value[NL_GOLEV] = level;
+}
+#endif