PR10026: Read marker/tracepoint args directly

We already stash the context variables for markers and tracepoints into
the locals for the probe body, but then we were using separate functions
to read those locals for each particular probe body.

This patch instead teaches the unparser how to emit the local name
directly for those context variables.  The resulting code from the
translator is much simpler now.

1 files changed, 28 insertions, 58 deletions

diff --git a/tapsets.cxx b/tapsets.cxx
index c4348a29..0ff26be8 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -8671,6 +8671,7 @@ struct mark_derived_probe: public derived_probe
   bool target_symbol_seen;
 
   void join_group (systemtap_session& s);
+  void print_dupe_stamp (ostream& o);
   void emit_probe_context_vars (translator_output* o);
   void initialize_probe_context_vars (translator_output* o);
   void printargs (std::ostream &o) const;
@@ -8774,36 +8775,9 @@ mark_var_expanding_visitor::visit_target_symbol_arg (target_symbol* e)
   // Remember that we've seen a target variable.
   target_symbol_seen = true;
 
-  // Synthesize a function.
-  functiondecl *fdecl = new functiondecl;
-  fdecl->tok = e->tok;
-  embeddedcode *ec = new embeddedcode;
-  ec->tok = e->tok;
-
-  string fname = string("_mark_tvar_get")
-    + "_" + e->base_name.substr(1)
-    + "_" + lex_cast<string>(tick++);
-
-  if (mark_args[argnum-1]->stp_type == pe_long)
-    ec->code = string("THIS->__retvalue = CONTEXT->locals[0].")
-      + probe_name + string(".__mark_arg")
-      + lex_cast<string>(argnum) + string (";");
-  else
-    ec->code = string("strlcpy (THIS->__retvalue, CONTEXT->locals[0].")
-      + probe_name + string(".__mark_arg")
-      + lex_cast<string>(argnum) + string (", MAXSTRINGLEN);");
-  ec->code += "/* pure */";
-  fdecl->name = fname;
-  fdecl->body = ec;
-  fdecl->type = mark_args[argnum-1]->stp_type;
-  sess.functions[fdecl->name]=fdecl;
-
-  // Synthesize a functioncall.
-  functioncall* n = new functioncall;
-  n->tok = e->tok;
-  n->function = fname;
-  n->referent = 0; // NB: must not resolve yet, to ensure inclusion in session
-  provide (n);
+  e->probe_context_var = "__mark_arg" + lex_cast<string>(argnum);
+  e->type = mark_args[argnum-1]->stp_type;
+  provide (e);
 }
 
 
@@ -9054,6 +9028,15 @@ mark_derived_probe::join_group (systemtap_session& s)
 
 
 void
+mark_derived_probe::print_dupe_stamp (ostream& o)
+{
+  if (target_symbol_seen)
+    for (unsigned i = 0; i < mark_args.size(); i++)
+      o << mark_args[i]->c_type << " __mark_arg" << (i+1) << endl;
+}
+
+
+void
 mark_derived_probe::emit_probe_context_vars (translator_output* o)
 {
   // If we haven't seen a target symbol for this probe, quit.
@@ -9391,6 +9374,7 @@ struct tracepoint_derived_probe: public derived_probe
   void build_args(dwflpp& dw, Dwarf_Die& func_die);
   void printargs (std::ostream &o) const;
   void join_group (systemtap_session& s);
+  void print_dupe_stamp(ostream& o);
   void emit_probe_context_vars (translator_output* o);
 };
 
@@ -9480,33 +9464,10 @@ tracepoint_var_expanding_visitor::visit_target_symbol_arg (target_symbol* e)
 
   if (e->components.empty())
     {
-      // Synthesize a simple function to grab the parameter
-      functiondecl *fdecl = new functiondecl;
-      fdecl->tok = e->tok;
-      embeddedcode *ec = new embeddedcode;
-      ec->tok = e->tok;
-
-      string fname = (string("_tracepoint_tvar_get")
-                      + "_" + e->base_name.substr(1)
-                      + "_" + lex_cast<string>(tick++));
-
-      fdecl->name = fname;
-      fdecl->body = ec;
-      fdecl->type = pe_long;
-
-      ec->code = (string("THIS->__retvalue = CONTEXT->locals[0].")
-                  + probe_name + string(".__tracepoint_arg_")
-                  + arg->name + string (";/* pure */"));
-
-      dw.sess.functions[fdecl->name] = fdecl;
-
-      // Synthesize a functioncall.
-      functioncall* n = new functioncall;
-      n->tok = e->tok;
-      n->function = fname;
-      n->referent = 0; // NB: must not resolve yet, to ensure inclusion in session
-
-      provide (n);
+      // Just grab the value from the probe locals
+      e->probe_context_var = "__tracepoint_arg_" + arg->name;
+      e->type = pe_long;
+      provide (e);
     }
   else
     {
@@ -9629,7 +9590,6 @@ tracepoint_var_expanding_visitor::visit_target_symbol_context (target_symbol* e)
     }
   else if (e->base_name == "$$vars" || e->base_name == "$$parms")
     {
-      target_symbol *tsym = new target_symbol;
       print_format* pf = new print_format;
 
       // Convert $$vars to sprintf of a list of vars which we recursively evaluate
@@ -9653,6 +9613,7 @@ tracepoint_var_expanding_visitor::visit_target_symbol_context (target_symbol* e)
           if (i > 0)
             pf->raw_components += " ";
           pf->raw_components += args[i].name;
+          target_symbol *tsym = new target_symbol;
           tsym->tok = e->tok;
           tsym->base_name = "$" + args[i].name;
 
@@ -9883,6 +9844,15 @@ tracepoint_derived_probe::join_group (systemtap_session& s)
 
 
 void
+tracepoint_derived_probe::print_dupe_stamp(ostream& o)
+{
+  for (unsigned i = 0; i < args.size(); i++)
+    if (args[i].used)
+      o << "__tracepoint_arg_" << args[i].name << endl;
+}
+
+
+void
 tracepoint_derived_probe::emit_probe_context_vars (translator_output* o)
 {
   for (unsigned i = 0; i < args.size(); i++)