Merge branch 'array_index'

14 files changed, 311 insertions, 249 deletions

diff --git a/dwflpp.cxx b/dwflpp.cxx
index e6e7b471..6ede1d68 100644
--- a/dwflpp.cxx
+++ b/dwflpp.cxx
@@ -1620,9 +1620,8 @@ dwflpp::print_members(Dwarf_Die *vardie, ostream &o)
 
 
 bool
-dwflpp::find_struct_member(const string& member,
+dwflpp::find_struct_member(const target_symbol::component& c,
                            Dwarf_Die *parentdie,
-                           const target_symbol *e,
                            Dwarf_Die *memberdie,
                            vector<Dwarf_Attribute>& locs)
 {
@@ -1640,7 +1639,7 @@ dwflpp::find_struct_member(const string& member,
       throw semantic_error (string (dwarf_tag(&die) == DW_TAG_union_type ? "union" : "struct")
                             + string (dwarf_diename_integrate (&die) ?: "<anonymous>")
                             + string (dwarf_errmsg (-1)),
-                            e->tok);
+                            c.tok);
     }
 
   do
@@ -1658,10 +1657,10 @@ dwflpp::find_struct_member(const string& member,
               !dwarf_formref_die (&attr, &subdie))
             continue;
 
-          if (find_struct_member(member, &subdie, e, memberdie, locs))
+          if (find_struct_member(c, &subdie, memberdie, locs))
             goto success;
         }
-      else if (name == member)
+      else if (name == c.member)
         {
           *memberdie = die;
           goto success;
@@ -1680,9 +1679,9 @@ success:
   /* Union members don't usually have a location,
    * but just use the containing union's location.  */
   else if (dwarf_tag(parentdie) != DW_TAG_union_type)
-    throw semantic_error ("no location for field '" + member
+    throw semantic_error ("no location for field '" + c.member
                           + "': " + string(dwarf_errmsg (-1)),
-                          e->tok);
+                          c.tok);
 
   return true;
 }
@@ -1709,6 +1708,8 @@ dwflpp::translate_components(struct obstack *pool,
 
   while (i < e->components.size())
     {
+      const target_symbol::component& c = e->components[i];
+
       /* XXX: This would be desirable, but we don't get the target_symbol token,
          and printing that gives us the file:line number too early anyway. */
 #if 0
@@ -1730,39 +1731,53 @@ dwflpp::translate_components(struct obstack *pool,
 
         case DW_TAG_pointer_type:
           c_translate_pointer (pool, 1, 0 /* PR9768*/, die, tail);
-          if (e->components[i].first != target_symbol::comp_literal_array_index)
+          if (c.type != target_symbol::comp_literal_array_index &&
+              c.type != target_symbol::comp_expression_array_index)
             break;
           /* else fall through as an array access */
 
         case DW_TAG_array_type:
-          if (e->components[i].first == target_symbol::comp_literal_array_index)
+          if (c.type == target_symbol::comp_literal_array_index)
             {
               c_translate_array (pool, 1, 0 /* PR9768 */, die, tail,
-                                 NULL, lex_cast<Dwarf_Word>(e->components[i].second));
+                                 NULL, c.num_index);
+              ++i;
+            }
+          else if (c.type == target_symbol::comp_expression_array_index)
+            {
+              string index = "THIS->index" + lex_cast<string>(i);
+              c_translate_array (pool, 1, 0 /* PR9768 */, die, tail,
+                                 index.c_str(), 0);
               ++i;
             }
           else
-            throw semantic_error("bad field '"
-                                 + e->components[i].second
-                                 + "' for array type",
-                                 e->tok);
+            throw semantic_error ("invalid access '"
+                                  + lex_cast<string>(c)
+                                  + "' for array type",
+                                  c.tok);
           break;
 
         case DW_TAG_structure_type:
         case DW_TAG_union_type:
+          if (c.type != target_symbol::comp_struct_member)
+            throw semantic_error ("invalid access '"
+                                  + lex_cast<string>(c)
+                                  + "' for struct/union type",
+                                  c.tok);
+
           if (dwarf_hasattr(die, DW_AT_declaration))
             {
               Dwarf_Die *tmpdie = dwflpp::declaration_resolve(dwarf_diename(die));
               if (tmpdie == NULL)
                 throw semantic_error ("unresolved struct "
                                       + string (dwarf_diename_integrate (die) ?: "<anonymous>"),
-                                      e->tok);
+                                      c.tok);
               *die_mem = *tmpdie;
             }
 
             {
               vector<Dwarf_Attribute> locs;
-              if (!find_struct_member(e->components[i].second, die, e, die, locs))
+              if (!find_struct_member(c, die, die, locs))
                 {
                   string alternatives;
                   stringstream members;
@@ -1770,10 +1785,10 @@ dwflpp::translate_components(struct obstack *pool,
                   if (members.str().size() != 0)
                     alternatives = " (alternatives:" + members.str();
                   throw semantic_error("unable to find member '" +
-                                       e->components[i].second + "' for struct "
+                                       c.member + "' for struct "
                                        + string(dwarf_diename_integrate(die) ?: "<unknown>")
                                        + alternatives,
-                                       e->tok);
+                                       c.tok);
                 }
 
               for (unsigned j = 0; j < locs.size(); ++j)
@@ -1784,39 +1799,41 @@ dwflpp::translate_components(struct obstack *pool,
           break;
 
         case DW_TAG_enumeration_type:
-          throw semantic_error ("field '"
-                                + e->components[i].second
+          throw semantic_error ("invalid access '"
+                                + lex_cast<string>(c)
                                 + "' vs. enum type "
                                 + string(dwarf_diename_integrate (die) ?: "<anonymous type>"),
-                                e->tok);
+                                c.tok);
           break;
         case DW_TAG_base_type:
-          throw semantic_error ("field '"
-                                + e->components[i].second
+          throw semantic_error ("invalid access '"
+                                + lex_cast<string>(c)
                                 + "' vs. base type "
                                 + string(dwarf_diename_integrate (die) ?: "<anonymous type>"),
-                                e->tok);
+                                c.tok);
           break;
         case -1:
           throw semantic_error ("cannot find type: " + string(dwarf_errmsg (-1)),
-                                e->tok);
+                                c.tok);
           break;
 
         default:
           throw semantic_error (string(dwarf_diename_integrate (die) ?: "<anonymous type>")
                                 + ": unexpected type tag "
                                 + lex_cast<string>(dwarf_tag (die)),
-                                e->tok);
+                                c.tok);
           break;
         }
 
       /* Now iterate on the type in DIE's attribute.  */
       if (dwarf_attr_integrate (die, DW_AT_type, attr_mem) == NULL)
-        throw semantic_error ("cannot get type of field: " + string(dwarf_errmsg (-1)), e->tok);
+        throw semantic_error ("cannot get type of field: " + string(dwarf_errmsg (-1)),
+                              c.tok);
     }
 
   /* For an array index, we need to dereference the final DIE */
-  if (e->components.back().first == target_symbol::comp_literal_array_index)
+  if (e->components.back().type == target_symbol::comp_literal_array_index ||
+      e->components.back().type == target_symbol::comp_expression_array_index)
     die = dwarf_formref_die (attr_mem, die_mem);
 
   return die;
diff --git a/dwflpp.h b/dwflpp.h
index 20bcc0d0..3cada4f8 100644
--- a/dwflpp.h
+++ b/dwflpp.h
@@ -333,9 +333,8 @@ private:
                                       struct location **tail,
                                       const target_symbol *e);
 
-  bool find_struct_member(const std::string& member,
+  bool find_struct_member(const target_symbol::component& c,
                           Dwarf_Die *parentdie,
-                          const target_symbol *e,
                           Dwarf_Die *memberdie,
                           std::vector<Dwarf_Attribute>& locs);
 
diff --git a/elaborate.cxx b/elaborate.cxx
index fafc5e63..d1ebe326 100644
--- a/elaborate.cxx
+++ b/elaborate.cxx
@@ -2534,6 +2534,7 @@ struct void_statement_reducer: public update_visitor
   void visit_concatenation (concatenation* e);
   void visit_functioncall (functioncall* e);
   void visit_print_format (print_format* e);
+  void visit_target_symbol (target_symbol* e);
   void visit_cast_op (cast_op* e);
 
   // these are a bit hairy to grok due to the intricacies of indexables and
@@ -2803,16 +2804,73 @@ void_statement_reducer::visit_print_format (print_format* e)
 }
 
 void
+void_statement_reducer::visit_target_symbol (target_symbol* e)
+{
+  // When target_symbol isn't needed, it's just as good to
+  // evaluate any array indexes directly
+
+  block *b = new block;
+  b->tok = e->tok;
+
+  for (unsigned i=0; i<e->components.size(); i++ )
+    {
+      if (e->components[i].type != target_symbol::comp_expression_array_index)
+        continue;
+
+      expr_statement *es = new expr_statement;
+      es->value = e->components[i].expr_index;
+      es->tok = es->value->tok;
+      b->statements.push_back(es);
+    }
+
+  if (b->statements.empty())
+    {
+      delete b;
+      provide (e);
+      return;
+    }
+
+  if (session.verbose>2)
+    clog << "Eliding unused target symbol " << *e->tok << endl;
+
+  b->visit(this);
+  relaxed_p = false;
+  e = 0;
+  provide (e);
+}
+
+void
 void_statement_reducer::visit_cast_op (cast_op* e)
 {
   // When the result of a cast operation isn't needed, it's just as good to
-  // evaluate the operand directly
+  // evaluate the operand and any array indexes directly
+
+  block *b = new block;
+  b->tok = e->tok;
+
+  expr_statement *es = new expr_statement;
+  es->value = e->operand;
+  es->tok = es->value->tok;
+  b->statements.push_back(es);
+
+  for (unsigned i=0; i<e->components.size(); i++ )
+    {
+      if (e->components[i].type != target_symbol::comp_expression_array_index)
+        continue;
+
+      es = new expr_statement;
+      es->value = e->components[i].expr_index;
+      es->tok = es->value->tok;
+      b->statements.push_back(es);
+    }
 
   if (session.verbose>2)
     clog << "Eliding unused typecast " << *e->tok << endl;
 
+  b->visit(this);
   relaxed_p = false;
-  e->operand->visit(this);
+  e = 0;
+  provide (e);
 }
 
 
diff --git a/parse.cxx b/parse.cxx
index 35c78abe..41a13ca5 100644
--- a/parse.cxx
+++ b/parse.cxx
@@ -2346,27 +2346,8 @@ parser::parse_symbol ()
               expect_unknown(tok_string, cop->module);
             }
 	  expect_op(")");
-	  while (true)
-	    {
-	      string c;
-	      if (peek_op ("->"))
-		{
-		  next();
-		  expect_ident_or_keyword (c);
-		  cop->components.push_back
-		    (make_pair (target_symbol::comp_struct_member, c));
-		}
-	      else if (peek_op ("["))
-		{
-		  next();
-		  expect_unknown (tok_number, c);
-		  expect_op ("]");
-		  cop->components.push_back
-		    (make_pair (target_symbol::comp_literal_array_index, c));
-		}
-	      else
-		break;
-	    }
+          parse_target_symbol_components(cop);
+
           // if there aren't any dereferences, then the cast is pointless
           if (cop->components.empty())
             {
@@ -2494,27 +2475,7 @@ parser::parse_symbol ()
 	  target_symbol *tsym = new target_symbol;
 	  tsym->tok = t;
 	  tsym->base_name = name;
-	  while (true)
-	    {
-	      string c;
-	      if (peek_op ("->"))
-		{
-		  next();
-		  expect_ident_or_keyword (c);
-		  tsym->components.push_back
-		    (make_pair (target_symbol::comp_struct_member, c));
-		}
-	      else if (peek_op ("["))
-		{
-		  next();
-		  expect_unknown (tok_number, c);
-		  expect_op ("]");
-		  tsym->components.push_back
-		    (make_pair (target_symbol::comp_literal_array_index, c));
-		}
-	      else
-		break;
-	    }
+          parse_target_symbol_components(tsym);
 	  return tsym;
 	}
 
@@ -2604,4 +2565,33 @@ parser::parse_symbol ()
   return sym;
 }
 
+
+void
+parser::parse_target_symbol_components (target_symbol* e)
+{
+  while (true)
+    {
+      if (peek_op ("->"))
+        {
+          const token* t = next();
+          string member;
+          expect_ident_or_keyword (member);
+          e->components.push_back (target_symbol::component(t, member));
+        }
+      else if (peek_op ("["))
+        {
+          const token* t = next();
+          expression* index = parse_expression();
+          literal_number* ln = dynamic_cast<literal_number*>(index);
+          if (ln)
+            e->components.push_back (target_symbol::component(t, ln->value));
+          else
+            e->components.push_back (target_symbol::component(t, index));
+          expect_op ("]");
+        }
+      else
+        break;
+    }
+}
+
 /* vim: set sw=2 ts=8 cino=>4,n-2,{2,^-2,t0,(0,u0,w1,M1 : */
diff --git a/parse.h b/parse.h
index cae49b65..5587586e 100644
--- a/parse.h
+++ b/parse.h
@@ -112,6 +112,7 @@ struct next_statement;
 struct continue_statement;
 struct indexable;
 struct expression;
+struct target_symbol;
 struct hist_op;
 
 class parser
@@ -203,6 +204,8 @@ private: // nonterminals
   expression* parse_crement ();
   expression* parse_value ();
   expression* parse_symbol ();
+
+  void parse_target_symbol_components (target_symbol* e);
 };
 
 
diff --git a/staptree.cxx b/staptree.cxx
index 9e2ca8da..50d9980f 100644
--- a/staptree.cxx
+++ b/staptree.cxx
@@ -186,6 +186,31 @@ operator << (ostream& o, const exp_type& e)
 }
 
 
+void
+target_symbol::assert_no_components(const std::string& tapset)
+{
+  if (components.empty())
+    return;
+
+  switch (components[0].type)
+    {
+    case target_symbol::comp_literal_array_index:
+    case target_symbol::comp_expression_array_index:
+      throw semantic_error(tapset + " variable '" + base_name +
+                           "' may not be used as array",
+                           components[0].tok);
+    case target_symbol::comp_struct_member:
+      throw semantic_error(tapset + " variable '" + base_name +
+                           "' may not be used as a structure",
+                           components[0].tok);
+    default:
+      throw semantic_error ("invalid use of " + tapset +
+                            " variable '" + base_name + "'",
+                            components[0].tok);
+    }
+}
+
+
 // ------------------------------------------------------------------------
 // parse tree printing
 
@@ -259,27 +284,41 @@ void symbol::print (ostream& o) const
 }
 
 
-void target_symbol::print (std::ostream& o) const
+void target_symbol::component::print (ostream& o) const
+{
+  switch (type)
+    {
+    case comp_struct_member:
+      o << "->" << member;
+      break;
+    case comp_literal_array_index:
+      o << '[' << num_index << ']';
+      break;
+    case comp_expression_array_index:
+      o << '[' << *expr_index << ']';
+      break;
+    }
+}
+
+
+std::ostream& operator << (std::ostream& o, const target_symbol::component& c)
+{
+  c.print (o);
+  return o;
+}
+
+
+void target_symbol::print (ostream& o) const
 {
   if (addressof)
     o << "&";
   o << base_name;
   for (unsigned i = 0; i < components.size(); ++i)
-    {
-      switch (components[i].first)
-	{
-	case comp_literal_array_index:
-	  o << '[' << components[i].second << ']';
-	  break;
-	case comp_struct_member:
-	  o << "->" << components[i].second;
-	  break;
-	}
-    }
+    o << components[i];
 }
 
 
-void cast_op::print (std::ostream& o) const
+void cast_op::print (ostream& o) const
 {
   if (addressof)
     o << "&";
@@ -289,17 +328,7 @@ void cast_op::print (std::ostream& o) const
     o << ", " << lex_cast_qstring (module);
   o << ')';
   for (unsigned i = 0; i < components.size(); ++i)
-    {
-      switch (components[i].first)
-	{
-	case comp_literal_array_index:
-	  o << '[' << components[i].second << ']';
-	  break;
-	case comp_struct_member:
-	  o << "->" << components[i].second;
-	  break;
-	}
-    }
+    o << components[i];
 }
 
 
@@ -1246,6 +1275,22 @@ target_symbol::visit (visitor* u)
 }
 
 void
+target_symbol::visit_components (visitor* u)
+{
+  for (unsigned i = 0; i < components.size(); ++i)
+    if (components[i].type == comp_expression_array_index)
+      components[i].expr_index->visit (u);
+}
+
+void
+target_symbol::visit_components (update_visitor* u)
+{
+  for (unsigned i = 0; i < components.size(); ++i)
+    if (components[i].type == comp_expression_array_index)
+      components[i].expr_index = u->require (components[i].expr_index);
+}
+
+void
 cast_op::visit (visitor* u)
 {
   u->visit_cast_op(this);
@@ -1613,14 +1658,16 @@ traversing_visitor::visit_symbol (symbol*)
 }
 
 void
-traversing_visitor::visit_target_symbol (target_symbol*)
+traversing_visitor::visit_target_symbol (target_symbol* e)
 {
+  e->visit_components (this);
 }
 
 void
 traversing_visitor::visit_cast_op (cast_op* e)
 {
   e->operand->visit (this);
+  e->visit_components (this);
 }
 
 void
@@ -1715,6 +1762,8 @@ varuse_collecting_visitor::visit_target_symbol (target_symbol *e)
 
   if (is_active_lvalue (e))
     embedded_seen = true;
+
+  functioncall_traversing_visitor::visit_target_symbol (e);
 }
 
 void
@@ -2348,6 +2397,7 @@ update_visitor::visit_symbol (symbol* e)
 void
 update_visitor::visit_target_symbol (target_symbol* e)
 {
+  e->visit_components (this);
   provide (e);
 }
 
@@ -2355,6 +2405,7 @@ void
 update_visitor::visit_cast_op (cast_op* e)
 {
   e->operand = require (e->operand);
+  e->visit_components (this);
   provide (e);
 }
 
diff --git a/staptree.h b/staptree.h
index 16f0256a..146d0e34 100644
--- a/staptree.h
+++ b/staptree.h
@@ -58,6 +58,7 @@ std::ostream& operator << (std::ostream& o, const exp_type& e);
 
 struct token;
 struct visitor;
+struct update_visitor;
 
 struct expression
 {
@@ -227,18 +228,42 @@ struct target_symbol: public symbol
   enum component_type
     {
       comp_struct_member,
-      comp_literal_array_index
+      comp_literal_array_index,
+      comp_expression_array_index,
     };
+
+  struct component
+    {
+      const token* tok;
+      component_type type;
+      std::string member; // comp_struct_member
+      int64_t num_index; // comp_literal_array_index
+      expression* expr_index; // comp_expression_array_index
+
+      component(const token* t, const std::string& m):
+        tok(t), type(comp_struct_member), member(m) {}
+      component(const token* t, int64_t n):
+        tok(t), type(comp_literal_array_index), num_index(n) {}
+      component(const token* t, expression* e):
+        tok(t), type(comp_expression_array_index), expr_index(e) {}
+      void print (std::ostream& o) const;
+    };
+
   bool addressof;
   std::string base_name;
-  std::vector<std::pair<component_type, std::string> > components;
+  std::vector<component> components;
   std::string probe_context_var;
   semantic_error* saved_conversion_error;
   target_symbol(): addressof(false), saved_conversion_error (0) {}
   void print (std::ostream& o) const;
   void visit (visitor* u);
+  void visit_components (visitor* u);
+  void visit_components (update_visitor* u);
+  void assert_no_components(const std::string& tapset);
 };
 
+std::ostream& operator << (std::ostream& o, const target_symbol::component& c);
+
 
 struct cast_op: public target_symbol
 {
diff --git a/tapset-mark.cxx b/tapset-mark.cxx
index a358a20e..59334729 100644
--- a/tapset-mark.cxx
+++ b/tapset-mark.cxx
@@ -103,23 +103,7 @@ mark_var_expanding_visitor::visit_target_symbol_arg (target_symbol* e)
   if (is_active_lvalue (e))
     throw semantic_error("write to marker parameter not permitted", e->tok);
 
-  if (e->components.size() > 0)
-    {
-      switch (e->components[0].first)
-	{
-	case target_symbol::comp_literal_array_index:
-	  throw semantic_error("marker argument may not be used as array",
-			       e->tok);
-	  break;
-	case target_symbol::comp_struct_member:
-	  throw semantic_error("marker argument may not be used as a structure",
-			       e->tok);
-	  break;
-	default:
-	  throw semantic_error ("invalid marker argument use", e->tok);
-	  break;
-	}
-    }
+  e->assert_no_components("marker");
 
   // Remember that we've seen a target variable.
   target_symbol_seen = true;
@@ -138,23 +122,7 @@ mark_var_expanding_visitor::visit_target_symbol_context (target_symbol* e)
   if (is_active_lvalue (e))
     throw semantic_error("write to marker '" + sname + "' not permitted", e->tok);
 
-  if (e->components.size() > 0)
-    {
-      switch (e->components[0].first)
-	{
-	case target_symbol::comp_literal_array_index:
-	  throw semantic_error("marker '" + sname + "' may not be used as array",
-			       e->tok);
-	  break;
-	case target_symbol::comp_struct_member:
-	  throw semantic_error("marker '" + sname + "' may not be used as a structure",
-			       e->tok);
-	  break;
-	default:
-	  throw semantic_error ("invalid marker '" + sname + "' use", e->tok);
-	  break;
-	}
-    }
+  e->assert_no_components("marker");
 
   if (e->base_name == "$format" || e->base_name == "$name") {
      string fname;
diff --git a/tapset-perfmon.cxx b/tapset-perfmon.cxx
index 0fb567f7..d524aa03 100644
--- a/tapset-perfmon.cxx
+++ b/tapset-perfmon.cxx
@@ -67,24 +67,7 @@ perfmon_var_expanding_visitor::visit_target_symbol (target_symbol *e)
   if (e->addressof)
     throw semantic_error("cannot take address of perfmon variable", e->tok);
 
-  if (e->components.size() > 0)
-    {
-      switch (e->components[0].first)
-        {
-        case target_symbol::comp_literal_array_index:
-          throw semantic_error("perfmon probe '$counter' variable may not be used as array",
-                               e->tok);
-          break;
-        case target_symbol::comp_struct_member:
-          throw semantic_error("perfmon probe '$counter' variable may not be used as a structure",
-                               e->tok);
-          break;
-        default:
-          throw semantic_error ("invalid use of perfmon probe '$counter' variable",
-                                e->tok);
-          break;
-        }
-    }
+  e->assert_no_components("perfmon");
 
   ec->code = "THIS->__retvalue = _pfm_pmd_x[" +
           lex_cast<string>(counter_number) + "].reg_num;";
diff --git a/tapset-procfs.cxx b/tapset-procfs.cxx
index a996ee32..3302057c 100644
--- a/tapset-procfs.cxx
+++ b/tapset-procfs.cxx
@@ -358,24 +358,7 @@ procfs_var_expanding_visitor::visit_target_symbol (target_symbol* e)
     throw semantic_error ("invalid target symbol for procfs probe, $value expected",
                           e->tok);
 
-  if (e->components.size() > 0)
-    {
-      switch (e->components[0].first)
-        {
-        case target_symbol::comp_literal_array_index:
-          throw semantic_error("procfs target variable '$value' may not be used as array",
-                               e->tok);
-          break;
-        case target_symbol::comp_struct_member:
-          throw semantic_error("procfs target variable '$value' may not be used as a structure",
-                               e->tok);
-          break;
-        default:
-          throw semantic_error ("invalid use of procfs target variable '$value'",
-                                e->tok);
-          break;
-        }
-    }
+  e->assert_no_components("procfs");
 
   bool lvalue = is_active_lvalue(e);
   if (write_probe && lvalue)
diff --git a/tapset-utrace.cxx b/tapset-utrace.cxx
index a3a4ca3d..87053f7d 100644
--- a/tapset-utrace.cxx
+++ b/tapset-utrace.cxx
@@ -455,24 +455,7 @@ utrace_var_expanding_visitor::visit_target_symbol_arg (target_symbol* e)
         string argnum_s = e->base_name.substr(4,e->base_name.length()-4);
         int argnum = lex_cast<int>(argnum_s);
 
-        if (e->components.size() > 0)
-         {
-           switch (e->components[0].first)
-     	    {
-	     case target_symbol::comp_literal_array_index:
-	       throw semantic_error("utrace target variable '$argN' may not be used as array",
-	   		            e->tok);
-	       break;
-	     case target_symbol::comp_struct_member:
-	       throw semantic_error("utrace target variable '$argN' may not be used as a structure",
-			            e->tok);
-	       break;
-  	     default:
-	       throw semantic_error ("invalid use of utrace target variable '$argN'",
-	  			     e->tok);
-	      break;
-	    }
-         }
+        e->assert_no_components("utrace");
 
         // FIXME: max argnument number should not be hardcoded.
         if (argnum < 1 || argnum > 6)
@@ -505,24 +488,7 @@ utrace_var_expanding_visitor::visit_target_symbol_context (target_symbol* e)
 {
   string sname = e->base_name;
 
-  if (e->components.size() > 0)
-    {
-      switch (e->components[0].first)
-	{
-	case target_symbol::comp_literal_array_index:
-	  throw semantic_error("utrace target variable '" + sname + "' may not be used as array",
-			       e->tok);
-	  break;
-	case target_symbol::comp_struct_member:
-	  throw semantic_error("utrace target variable '" + sname + "' may not be used as a structure",
-			       e->tok);
-	  break;
-	default:
-	  throw semantic_error ("invalid use of utrace target variable '" + sname + "'",
-				e->tok);
-	  break;
-	}
-    }
+  e->assert_no_components("utrace");
 
   bool lvalue = is_active_lvalue(e);
   if (lvalue)
diff --git a/tapsets.cxx b/tapsets.cxx
index bd33fb0b..ba344c51 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -2244,7 +2244,6 @@ dwarf_var_expanding_visitor::visit_target_symbol (target_symbol *e)
 	  // quietly.
 	  provide (e);
 	  semantic_error* saveme = new semantic_error (er); // copy it
-	  saveme->tok1 = e->tok; // XXX: token not passed to q.dw code generation routines
 	  // NB: we can have multiple errors, since a $target variable
 	  // may be expanded in several different contexts:
 	  //     function ("*") { $var }
@@ -2269,6 +2268,18 @@ dwarf_var_expanding_visitor::visit_target_symbol (target_symbol *e)
 
   fdecl->name = fname;
   fdecl->body = ec;
+
+  // Any non-literal indexes need to be passed in too.
+  for (unsigned i = 0; i < e->components.size(); ++i)
+    if (e->components[i].type == target_symbol::comp_expression_array_index)
+      {
+        vardecl *v = new vardecl;
+        v->type = pe_long;
+        v->name = "index" + lex_cast<string>(i);
+        v->tok = e->tok;
+        fdecl->formal_args.push_back(v);
+      }
+
   if (lvalue)
     {
       // Modify the fdecl so it carries a single pe_long formal
@@ -2293,6 +2304,11 @@ dwarf_var_expanding_visitor::visit_target_symbol (target_symbol *e)
   n->function = fname;
   n->referent = 0;  // NB: must not resolve yet, to ensure inclusion in session
 
+  // Any non-literal indexes need to be passed in too.
+  for (unsigned i = 0; i < e->components.size(); ++i)
+    if (e->components[i].type == target_symbol::comp_expression_array_index)
+      n->args.push_back(require(e->components[i].expr_index));
+
   if (lvalue)
     {
       // Provide the functioncall to our parent, so that it can be
@@ -2522,6 +2538,17 @@ void dwarf_cast_expanding_visitor::visit_cast_op (cast_op* e)
   v1->tok = e->tok;
   fdecl->formal_args.push_back(v1);
 
+  // Any non-literal indexes need to be passed in too.
+  for (unsigned i = 0; i < e->components.size(); ++i)
+    if (e->components[i].type == target_symbol::comp_expression_array_index)
+      {
+        vardecl *v = new vardecl;
+        v->type = pe_long;
+        v->name = "index" + lex_cast<string>(i);
+        v->tok = e->tok;
+        fdecl->formal_args.push_back(v);
+      }
+
   if (lvalue)
     {
       // Modify the fdecl so it carries a second pe_long formal
@@ -2550,6 +2577,11 @@ void dwarf_cast_expanding_visitor::visit_cast_op (cast_op* e)
   n->referent = 0;  // NB: must not resolve yet, to ensure inclusion in session
   n->args.push_back(e->operand);
 
+  // Any non-literal indexes need to be passed in too.
+  for (unsigned i = 0; i < e->components.size(); ++i)
+    if (e->components[i].type == target_symbol::comp_expression_array_index)
+      n->args.push_back(require(e->components[i].expr_index));
+
   if (lvalue)
     {
       // Provide the functioncall to our parent, so that it can be
@@ -3278,7 +3310,7 @@ sdt_var_expanding_visitor::visit_target_symbol (target_symbol *e)
   cast->type = probe_name + "_arg" + lex_cast<string>(argno);
   cast->module = process_name;
 
-  provide(cast);
+  cast->visit(this);
 }
 
 
@@ -5262,19 +5294,8 @@ tracepoint_var_expanding_visitor::visit_target_symbol_arg (target_symbol* e)
     }
 
   // make sure we're not dereferencing base types
-  if (!e->components.empty() && !arg->isptr)
-    switch (e->components[0].first)
-      {
-      case target_symbol::comp_literal_array_index:
-        throw semantic_error("tracepoint variable '" + e->base_name
-                             + "' may not be used as array", e->tok);
-      case target_symbol::comp_struct_member:
-        throw semantic_error("tracepoint variable '" + e->base_name
-                             + "' may not be used as a structure", e->tok);
-      default:
-        throw semantic_error("invalid use of tracepoint variable '"
-                             + e->base_name + "'", e->tok);
-      }
+  if (!arg->isptr)
+    e->assert_no_components("tracepoint");
 
   // we can only write to dereferenced fields, and only if guru mode is on
   bool lvalue = is_active_lvalue(e);
@@ -5323,7 +5344,6 @@ tracepoint_var_expanding_visitor::visit_target_symbol_arg (target_symbol* e)
           // up not being referenced after all, so it can be optimized out
           // quietly.
           semantic_error* saveme = new semantic_error (er); // copy it
-          saveme->tok1 = e->tok; // XXX: token not passed to dw code generation routines
           // NB: we can have multiple errors, since a target variable
           // may be expanded in several different contexts:
           //     trace ("*") { $foo->bar }
@@ -5340,6 +5360,17 @@ tracepoint_var_expanding_visitor::visit_target_symbol_arg (target_symbol* e)
       v1->tok = e->tok;
       fdecl->formal_args.push_back(v1);
 
+      // Any non-literal indexes need to be passed in too.
+      for (unsigned i = 0; i < e->components.size(); ++i)
+        if (e->components[i].type == target_symbol::comp_expression_array_index)
+          {
+            vardecl *v = new vardecl;
+            v->type = pe_long;
+            v->name = "index" + lex_cast<string>(i);
+            v->tok = e->tok;
+            fdecl->formal_args.push_back(v);
+          }
+
       if (lvalue)
         {
           // Modify the fdecl so it carries a pe_long formal
@@ -5367,10 +5398,16 @@ tracepoint_var_expanding_visitor::visit_target_symbol_arg (target_symbol* e)
       n->function = fname;
       n->referent = 0; // NB: must not resolve yet, to ensure inclusion in session
 
-      // make the original a bare target symbol for the tracepoint value,
-      // which will be passed into the dwarf dereferencing code
-      e->components.clear();
-      n->args.push_back(require(e));
+      // make a copy of the original as a bare target symbol for the tracepoint
+      // value, which will be passed into the dwarf dereferencing code
+      target_symbol* e2 = deep_copy_visitor::deep_copy(e);
+      e2->components.clear();
+      n->args.push_back(require(e2));
+
+      // Any non-literal indexes need to be passed in too.
+      for (unsigned i = 0; i < e->components.size(); ++i)
+        if (e->components[i].type == target_symbol::comp_expression_array_index)
+          n->args.push_back(require(e->components[i].expr_index));
 
       if (lvalue)
         {
@@ -5395,18 +5432,7 @@ tracepoint_var_expanding_visitor::visit_target_symbol_context (target_symbol* e)
   if (is_active_lvalue (e))
     throw semantic_error("write to tracepoint '" + e->base_name + "' not permitted", e->tok);
 
-  if (!e->components.empty())
-    switch (e->components[0].first)
-      {
-      case target_symbol::comp_literal_array_index:
-        throw semantic_error("tracepoint '" + e->base_name + "' may not be used as array",
-                             e->tok);
-      case target_symbol::comp_struct_member:
-        throw semantic_error("tracepoint '" + e->base_name + "' may not be used as a structure",
-                             e->tok);
-      default:
-        throw semantic_error("invalid tracepoint '" + e->base_name + "' use", e->tok);
-      }
+  e->assert_no_components("tracepoint");
 
   if (e->base_name == "$$name")
     {
diff --git a/testsuite/systemtap.base/pointer_array.stp b/testsuite/systemtap.base/pointer_array.stp
index 1d15ebf4..cd420604 100644
--- a/testsuite/systemtap.base/pointer_array.stp
+++ b/testsuite/systemtap.base/pointer_array.stp
@@ -2,15 +2,8 @@ probe syscall.execve
 {
     if (pid() == target()) {
         println(user_string($argv[0]))
-        printf("%c\n", $argv[0][0])
-        printf("%c\n", $argv[0][1])
-        printf("%c\n", $argv[0][2])
-        printf("%c\n", $argv[0][3])
-        printf("%c\n", $argv[0][4])
-        printf("%c\n", $argv[0][5])
-        printf("%c\n", $argv[0][6])
-        printf("%c\n", $argv[0][7])
-        printf("%c\n", $argv[0][8])
+        for (i=0; i<9; ++i)
+            printf("%c\n", $argv[0][i])
         println($argv[0][9])
     }
 }
diff --git a/translate.cxx b/translate.cxx
index f2e04d7d..a26e4085 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -3515,7 +3515,7 @@ c_unparser::visit_target_symbol (target_symbol* e)
   if (!e->probe_context_var.empty())
     o->line() << "l->" << e->probe_context_var;
   else
-    throw semantic_error("cannot translate general cast expression", e->tok);
+    throw semantic_error("cannot translate general target expression", e->tok);
 }