From 40b71c4777ca110d69d5d61563d032a5ba1355df Mon Sep 17 00:00:00 2001
From: Mark Wielaard <mjw@redhat.com>
Date: Mon, 21 Dec 2009 22:37:20 +0100
Subject: [PATCH] PR11038 Trailing semicolon as null-statement confusing.

* parse.cxx (parser::parse_statement): Squash semicolon after non-block-like
  statements.
* testsuite/buildok/semicolon.stp: New test.
---
 parse.cxx                       | 35 +++++++++++++++++++++------------
 testsuite/buildok/semicolon.stp | 18 +++++++++++++++++
 2 files changed, 40 insertions(+), 13 deletions(-)
 create mode 100644 testsuite/buildok/semicolon.stp

diff --git a/parse.cxx b/parse.cxx
index 74d7c634e..55ec53fb4 100644
--- a/parse.cxx
+++ b/parse.cxx
@@ -1207,6 +1207,7 @@ parser::parse_stmt_block ()
 statement*
 parser::parse_statement ()
 {
+  statement *ret;
   const token* t = peek ();
   if (t && t->type == tok_operator && t->content == ";")
     {
@@ -1215,34 +1216,42 @@ parser::parse_statement ()
       return n;
     }
   else if (t && t->type == tok_operator && t->content == "{")
-    return parse_stmt_block ();
+    return parse_stmt_block (); // Don't squash semicolons.
   else if (t && t->type == tok_keyword && t->content == "if")
-    return parse_if_statement ();
+    return parse_if_statement (); // Don't squash semicolons.
   else if (t && t->type == tok_keyword && t->content == "for")
-    return parse_for_loop ();
+    return parse_for_loop (); // Don't squash semicolons.
   else if (t && t->type == tok_keyword && t->content == "foreach")
-    return parse_foreach_loop ();
+    return parse_foreach_loop (); // Don't squash semicolons.
+  else if (t && t->type == tok_keyword && t->content == "while")
+    return parse_while_loop (); // Don't squash semicolons.
   else if (t && t->type == tok_keyword && t->content == "return")
-    return parse_return_statement ();
+    ret = parse_return_statement ();
   else if (t && t->type == tok_keyword && t->content == "delete")
-    return parse_delete_statement ();
-  else if (t && t->type == tok_keyword && t->content == "while")
-    return parse_while_loop ();
+    ret = parse_delete_statement ();
   else if (t && t->type == tok_keyword && t->content == "break")
-    return parse_break_statement ();
+    ret = parse_break_statement ();
   else if (t && t->type == tok_keyword && t->content == "continue")
-    return parse_continue_statement ();
+    ret = parse_continue_statement ();
   else if (t && t->type == tok_keyword && t->content == "next")
-    return parse_next_statement ();
-  // XXX: "do/while" statement?
+    ret = parse_next_statement ();
   else if (t && (t->type == tok_operator || // expressions are flexible
                  t->type == tok_identifier ||
                  t->type == tok_number ||
                  t->type == tok_string))
-    return parse_expr_statement ();
+    ret = parse_expr_statement ();
   // XXX: consider generally accepting tok_embedded here too
   else
     throw parse_error ("expected statement");
+
+  // Squash "empty" trailing colons after any "non-block-like" statement.
+  t = peek ();
+  if (t && t->type == tok_operator && t->content == ";")
+    {
+      next (); // Silently eat trailing ; after statement
+    }
+
+  return ret;
 }
 
 
diff --git a/testsuite/buildok/semicolon.stp b/testsuite/buildok/semicolon.stp
new file mode 100644
index 000000000..0ec419568
--- /dev/null
+++ b/testsuite/buildok/semicolon.stp
@@ -0,0 +1,18 @@
+#! stap -p4
+
+# Test that semicolons are really optional (in non-block-like context).
+# PR11038.
+
+global x = 0;
+probe begin
+{
+  if (x) log("true") else log("false")
+  if (x) { log("true") } else { log("false") }
+  if (x) log("true"); else log("false")
+  if (x) log("true") else log("false");
+}
+
+probe end
+{
+  x = 1;
+}
-- 
2.43.5