Enable session-wide code filtering

This will be used to hook to dwarf_builder to all functions and probes
so it can attempt @cast expansion.

* session.h (systemtap_session): Add a vector of update_visitors
that will act as filters for all probes and functions.
* elaborate.cxx (semantic_pass_symbols): Run probes and functions
through each registered code filter.

3 files changed, 18 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 5f8e6ff3..e7f736cc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2009-02-11  Josh Stone  <jistone@redhat.com>
 
+	* session.h (systemtap_session): Add a vector of update_visitors
+	that will act as filters for all probes and functions.
+	* elaborate.cxx (semantic_pass_symbols): Run probes and functions
+	through each registered code filter.
+
+2009-02-11  Josh Stone  <jistone@redhat.com>
+
 	* tapsets.cxx (dwarf_var_expanding_visitor::visit_cast_op):  While
 	expanding dwarf probes, provide the current module as a default to
 	@casts without a module name.
diff --git a/elaborate.cxx b/elaborate.cxx
index 981fc7c7..9f8aa450 100644
--- a/elaborate.cxx
+++ b/elaborate.cxx
@@ -1092,6 +1092,9 @@ semantic_pass_symbols (systemtap_session& s)
 
           try
             {
+              for (unsigned j=0; j<s.code_filters.size(); j++)
+                fd->body = s.code_filters[j]->require (fd->body);
+
               sym.current_function = fd;
               sym.current_probe = 0;
               fd->body->visit (& sym);
@@ -1124,6 +1127,9 @@ semantic_pass_symbols (systemtap_session& s)
 
               try
                 {
+                  for (unsigned k=0; k<s.code_filters.size(); k++)
+                    dp->body = s.code_filters[k]->require (dp->body);
+
                   sym.current_function = 0;
                   sym.current_probe = dp;
                   dp->body->visit (& sym);
diff --git a/session.h b/session.h
index 6bcebd8b..735ef200 100644
--- a/session.h
+++ b/session.h
@@ -45,6 +45,7 @@ struct translator_output;
 struct unparser;
 struct semantic_error;
 struct module_cache;
+struct update_visitor;
 
 
 // XXX: a generalized form of this descriptor could be associated with
@@ -133,6 +134,10 @@ struct systemtap_session
   stapfile* user_file;
   std::vector<stapfile*> library_files;
 
+  // filters to run over all code before symbol resolution
+  //   e.g. @cast expansion
+  std::vector<update_visitor*> code_filters;
+
   // resolved globals/functions/probes for the run as a whole
   std::vector<stapfile*> files;
   std::vector<vardecl*> globals;