diff --git a/mozilla/js/ref/js.c b/mozilla/js/ref/js.c
index 76f56953c8e..862632023ff 100644
--- a/mozilla/js/ref/js.c
+++ b/mozilla/js/ref/js.c
@@ -565,8 +565,8 @@ SrcNotes(JSContext *cx, JSFunction *fun )
 		       (uintN) js_GetSrcNoteOffset(sn, 1),
 		       (uintN) js_GetSrcNoteOffset(sn, 2));
 		break;
-	      case SRC_COMMA:
 	      case SRC_PCBASE:
+	      case SRC_PCDELTA:
 		printf(" offset %u", (uintN) js_GetSrcNoteOffset(sn, 0));
 		break;
 	      case SRC_LABEL:
diff --git a/mozilla/js/ref/jsemit.c b/mozilla/js/ref/jsemit.c
index b7f49902922..4e413a73e73 100644
--- a/mozilla/js/ref/jsemit.c
+++ b/mozilla/js/ref/jsemit.c
@@ -863,7 +863,7 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
 		}
 		if (pn3->pn_type == TOK_DEFAULT)
 		    continue;
-		caseNoteIndex = js_NewSrcNote2(cx, cg, SRC_COMMA, 0);
+		caseNoteIndex = js_NewSrcNote2(cx, cg, SRC_PCDELTA, 0);
 		if (caseNoteIndex < 0)
 		    return JS_FALSE;
 		off = js_Emit3(cx, cg, JSOP_CASE, 0, 0);
@@ -1548,7 +1548,7 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
 	    if (!pn2->pn_next)
 		break;
 	    off = tmp;
-	    noteIndex = js_NewSrcNote2(cx, cg, SRC_COMMA, 0);
+	    noteIndex = js_NewSrcNote2(cx, cg, SRC_PCDELTA, 0);
 	    if (noteIndex < 0 ||
 		js_Emit1(cx, cg, JSOP_POP) < 0) {
 		return JS_FALSE;
@@ -1626,7 +1626,7 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
 
       case TOK_COMMA:
 	/*
-	 * Emit SRC_COMMA notes on each JSOP_POP between comma operands.
+	 * Emit SRC_PCDELTA notes on each JSOP_POP between comma operands.
 	 * These notes help the decompiler bracket the bytecodes generated
 	 * from each sub-expression that follows a comma.
 	 */
@@ -1642,7 +1642,7 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
 	    if (!pn2->pn_next)
 		break;
 	    off = tmp;
-	    noteIndex = js_NewSrcNote2(cx, cg, SRC_COMMA, 0);
+	    noteIndex = js_NewSrcNote2(cx, cg, SRC_PCDELTA, 0);
 	    if (noteIndex < 0 ||
 		js_Emit1(cx, cg, JSOP_POP) < 0) {
 		return JS_FALSE;
@@ -2016,7 +2016,7 @@ js_EmitTree(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
 
 	if (pn->pn_extra) {
 	    /* Emit a source note so we know to decompile an extra comma. */
-	    if (js_NewSrcNote(cx, cg, SRC_COMMA) < 0)
+	    if (js_NewSrcNote(cx, cg, SRC_PCDELTA) < 0)
 		return JS_FALSE;
 	}
 
@@ -2170,7 +2170,7 @@ JS_FRIEND_DATA(const char *) js_SrcNoteName[] = {
     "for",
     "continue",
     "var",
-    "comma",
+    "pcdelta",
     "assignop",
     "cond",
     "paren",
@@ -2198,7 +2198,7 @@ uint8 js_SrcNoteArity[] = {
     3,  /* SRC_FOR */
     0,  /* SRC_CONTINUE */
     0,  /* SRC_VAR */
-    1,  /* SRC_COMMA */
+    1,  /* SRC_PCDELTA */
     0,  /* SRC_ASSIGNOP */
     0,  /* SRC_COND */
     0,  /* SRC_PAREN */
diff --git a/mozilla/js/ref/jsemit.h b/mozilla/js/ref/jsemit.h
index 1d5056beb81..1843e382d62 100644
--- a/mozilla/js/ref/jsemit.h
+++ b/mozilla/js/ref/jsemit.h
@@ -231,7 +231,8 @@ typedef enum JSSrcNoteType {
     SRC_FOR         = 4,        /* JSOP_NOP or JSOP_POP in for loop head */
     SRC_CONTINUE    = 5,        /* JSOP_GOTO is a continue, not a break */
     SRC_VAR         = 6,        /* JSOP_NAME/FORNAME with a var declaration */
-    SRC_COMMA       = 7,        /* JSOP_POP representing a comma operator */
+    SRC_PCDELTA     = 7,        /* offset from comma-operator to next POP,
+				   or from CONDSWITCH to first CASE opcode */
     SRC_ASSIGNOP    = 8,        /* += or another assign-op follows */
     SRC_COND        = 9,        /* JSOP_IFEQ is from conditional ?: operator */
     SRC_PAREN       = 10,       /* JSOP_NOP generated to mark user parens */
diff --git a/mozilla/js/ref/jsopcode.c b/mozilla/js/ref/jsopcode.c
index 41d42a9d388..df96c82d94e 100644
--- a/mozilla/js/ref/jsopcode.c
+++ b/mozilla/js/ref/jsopcode.c
@@ -938,7 +938,7 @@ Decompile(SprintStack *ss, jsbytecode *pc, intN nb)
 		    todo = -2;
 		    goto do_forloop;
 
-		  case SRC_COMMA:
+		  case SRC_PCDELTA:
 		    /* Pop and save to avoid blowing stack depth budget. */
 		    lval = JS_strdup(cx, POP_STR());
 		    if (!lval)
@@ -1681,7 +1681,7 @@ Decompile(SprintStack *ss, jsbytecode *pc, intN nb)
 			off2 = 0;
 		    } else {
 			sn = js_GetSrcNote(jp->script, pc2);
-			PR_ASSERT(sn && SN_TYPE(sn) == SRC_COMMA);
+			PR_ASSERT(sn && SN_TYPE(sn) == SRC_PCDELTA);
 			off2 = js_GetSrcNoteOffset(sn, 0);
 		    }
 		}
@@ -1704,7 +1704,7 @@ Decompile(SprintStack *ss, jsbytecode *pc, intN nb)
 		    table[i].offset = caseOff + GET_JUMP_OFFSET(pc2);
 		    if (*pc2 == JSOP_CASE) {
 			sn = js_GetSrcNote(jp->script, pc2);
-			PR_ASSERT(sn && SN_TYPE(sn) == SRC_COMMA);
+			PR_ASSERT(sn && SN_TYPE(sn) == SRC_PCDELTA);
 			off2 = js_GetSrcNoteOffset(sn, 0);
 		    }
 		}
@@ -1860,7 +1860,7 @@ Decompile(SprintStack *ss, jsbytecode *pc, intN nb)
 		sn = js_GetSrcNote(jp->script, pc);
 		todo = Sprint(&ss->sprinter, "%s%s%c",
 			      rval,
-			      (sn && SN_TYPE(sn) == SRC_COMMA) ? ", " : "",
+			      (sn && SN_TYPE(sn) == SRC_PCDELTA) ? ", " : "",
 			      /* [balance */
 			      (*rval == '{') ? '}' : ']');
 		break;