From 03c75a4a21ef3dba8abbc7e596d2a102427a3d96 Mon Sep 17 00:00:00 2001
From: Josh Stone <jistone@redhat.com>
Date: Wed, 15 Jul 2009 18:21:56 -0700
Subject: PR5930: Address-op for $target and @cast members

This allows the '&' operator to get the address of @cast and $target
variable expressions.

* staptree.h (target_symbol): add addressof field
* staptree.cxx (target_symbol::print): print '&' for addressof
  (cast_op::print): ditto
* parse.cxx (parser::parse_value): allow '&' prefix on $target/@cast
* dwflpp.cxx (dwflpp::translate_final_fetch_or_store): allow taking the
  computed address without actually doing a final fetch.
* tapset* (*::visit_target_symbol): throw errors for $vars w/o addresses
* testsuite/systemtap.base/cast.stp: add &@cast test
* testsuite/semok/target_addr.stp: test '&' on different member types
* testsuite/semko/target_addr?.stp: test failure on bitfields/registers
---
 tapsets.cxx | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

(limited to 'tapsets.cxx')

diff --git a/tapsets.cxx b/tapsets.cxx
index 9ca25b0b..f629d08c 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -2331,6 +2331,9 @@ dwarf_var_expanding_visitor::visit_target_symbol (target_symbol *e)
       if (dwarf_getscopes_die (scope_die, &scopes) == 0)
 	return;
 
+      if (e->addressof)
+        throw semantic_error("cannot take address of context variable", e->tok);
+
       target_symbol *tsym = new target_symbol;
       print_format* pf = new print_format;
 
@@ -3356,6 +3359,9 @@ sdt_var_expanding_visitor::visit_target_symbol (target_symbol *e)
 {
   if (e->base_name == "$$name")
     {
+      if (e->addressof)
+        throw semantic_error("cannot take address of sdt variable", e->tok);
+
       literal_string *myname = new literal_string (probe_name);
       myname->tok = e->tok;
       provide(myname);
@@ -3409,6 +3415,9 @@ sdt_var_expanding_visitor::visit_target_symbol (target_symbol *e)
 
   if (e->components.empty())
     {
+      if (e->addressof)
+        throw semantic_error("cannot take address of sdt variable", e->tok);
+
       provide(fc);
       return;
     }
@@ -5041,6 +5050,9 @@ tracepoint_var_expanding_visitor::visit_target_symbol_arg (target_symbol* e)
 
   if (e->components.empty())
     {
+      if (e->addressof)
+        throw semantic_error("cannot take address of tracepoint variable", e->tok);
+
       // Just grab the value from the probe locals
       e->probe_context_var = "__tracepoint_arg_" + arg->name;
       e->type = pe_long;
@@ -5140,6 +5152,9 @@ tracepoint_var_expanding_visitor::visit_target_symbol_arg (target_symbol* e)
 void
 tracepoint_var_expanding_visitor::visit_target_symbol_context (target_symbol* e)
 {
+  if (e->addressof)
+    throw semantic_error("cannot take address of context variable", e->tok);
+
   if (is_active_lvalue (e))
     throw semantic_error("write to tracepoint '" + e->base_name + "' not permitted", e->tok);
 
-- 
cgit