From 3d69c03f37c05136a01481994e239f1287138f6a Mon Sep 17 00:00:00 2001
From: Josh Stone <jistone@redhat.com>
Date: Fri, 28 Oct 2011 14:42:23 -0700
Subject: [PATCH] plt: Throw an appropriate error for missing $var

* tapsets.cxx (plt_expanding_visitor::visit_target_symbol): Throw a
  semantic_error for missing $var, so it may be caught and chained for
  later.  This ensures that the visitor always has a provide() too.
* testsuite/semko/plt1.stp: New, check that missing $var is an error.
* testsuite/semok/plt1.stp: New, check that $$name works, as does
  @defined on a missing $var.
---
 tapsets.cxx              | 6 ++++++
 testsuite/semko/plt1.stp | 6 ++++++
 testsuite/semok/plt1.stp | 6 ++++++
 3 files changed, 18 insertions(+)
 create mode 100755 testsuite/semko/plt1.stp
 create mode 100755 testsuite/semok/plt1.stp

diff --git a/tapsets.cxx b/tapsets.cxx
index 29fb6f1b6..7eceafafe 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -5688,6 +5688,12 @@ plt_expanding_visitor::visit_target_symbol (target_symbol *e)
 	  provide(myname);
 	  return;
 	}
+
+      // variable not found -> throw a semantic error
+      // (only to be caught right away, but this may be more complex later...)
+      string alternatives = "$$name";
+      throw semantic_error(_F("unable to find plt variable '%s' (alternatives: %s)",
+                              e->name.c_str(), alternatives.c_str()), e->tok);
     }
   catch (const semantic_error &er)
     {
diff --git a/testsuite/semko/plt1.stp b/testsuite/semko/plt1.stp
new file mode 100755
index 000000000..cea5bf7ee
--- /dev/null
+++ b/testsuite/semko/plt1.stp
@@ -0,0 +1,6 @@
+#! stap -p2
+
+probe process("stap").plt {
+    println($no_such_var)
+}
+
diff --git a/testsuite/semok/plt1.stp b/testsuite/semok/plt1.stp
new file mode 100755
index 000000000..ecff19a3a
--- /dev/null
+++ b/testsuite/semok/plt1.stp
@@ -0,0 +1,6 @@
+#! stap -p2
+
+probe process("stap").plt {
+    println($$name)
+    println(@defined($no_such_var) ? $no_such_var : 0)
+}
-- 
2.43.5