7085 add support for "if" and "else" statements in dtrace

@@ -19,12 +19,12 @@
  * CDDL HEADER END
  */
 
 /*
  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
  * Copyright (c) 2013, Joyent Inc. All rights reserved.
- * Copyright (c) 2012 by Delphix. All rights reserved.
  * Copyright 2015 Gary Mills
  */
 
 /*
  * DTrace D Language Compiler

@@ -117,11 +117,10 @@
 };
 
 static void *dt_compile(dtrace_hdl_t *, int, dtrace_probespec_t, void *,
     uint_t, int, char *const[], FILE *, const char *);
 
-
 /*ARGSUSED*/
 static int
 dt_idreset(dt_idhash_t *dhp, dt_ident_t *idp, void *ignored)
 {
         idp->di_flags &= ~(DT_IDFLG_REF | DT_IDFLG_MOD |

@@ -2417,10 +2416,32 @@
                 xyerror(D_MACRO_UNUSED, "extraneous argument '%s' ($%d is "
                     "not referenced)\n", yypcb->pcb_sargv[argc - 1], argc - 1);
         }
 
         /*
+         * Perform sugar transformations (for "if" / "else") and replace the
+         * existing clause chain with the new one.
+         */
+        if (context == DT_CTX_DPROG) {
+                dt_node_t *dnp, *next_dnp;
+                dt_node_t *new_list = NULL;
+
+                for (dnp = yypcb->pcb_root->dn_list;
+                    dnp != NULL; dnp = next_dnp) {
+                        /* remove this node from the list */
+                        next_dnp = dnp->dn_list;
+                        dnp->dn_list = NULL;
+
+                        if (dnp->dn_kind == DT_NODE_CLAUSE)
+                                dnp = dt_compile_sugar(dtp, dnp);
+                        /* append node to the new list */
+                        new_list = dt_node_link(new_list, dnp);
+                }
+                yypcb->pcb_root->dn_list = new_list;
+        }
+
+        /*
          * If we have successfully created a parse tree for a D program, loop
          * over the clauses and actions and instantiate the corresponding
          * libdtrace program.  If we are parsing a D expression, then we
          * simply run the code generator and assembler on the resulting tree.
          */

@@ -2436,10 +2457,12 @@
                         longjmp(yypcb->pcb_jmpbuf, dtrace_errno(dtp));
 
                 for (; dnp != NULL; dnp = dnp->dn_list) {
                         switch (dnp->dn_kind) {
                         case DT_NODE_CLAUSE:
+                                if (DT_TREEDUMP_PASS(dtp, 4))
+                                        dt_printd(dnp, stderr, 0);
                                 dt_compile_clause(dtp, dnp);
                                 break;
                         case DT_NODE_XLATOR:
                                 if (dtp->dt_xlatemode == DT_XL_DYNAMIC)
                                         dt_compile_xlator(dnp);