Allow modules to trigger task_finder vma_tracker.

* runtime/sym.h: Define _stp_need_vma_tracker.
* translate.cxx (emit_symbol_data_done): Output _stp_need_vma_tracker value.
  (c_unparser::emit_module_init): If STP_NEED_VMA_TRACKER isn't defined
  check _stp_need_vma_tracker to call _stp_sym_init().

2 files changed, 11 insertions, 0 deletions

diff --git a/runtime/sym.h b/runtime/sym.h
index ca69345f..9f2bdfd0 100644
--- a/runtime/sym.h
+++ b/runtime/sym.h
@@ -66,6 +66,10 @@ static unsigned _stp_num_modules;
 /* load address, fixup by transport symbols _stp_do_relocation */
 static unsigned long _stp_kretprobe_trampoline;
 
+/* Indicates some modules requested the task finder to notify sym.c
+   _stp_sym_init () should track vma maps. */
+static char _stp_need_vma_tracker;
+
 static unsigned long _stp_module_relocate (const char *module, const char *section, unsigned long offset);
 static struct _stp_module *_stp_get_unwind_info (unsigned long addr);
 
diff --git a/translate.cxx b/translate.cxx
index cbb8f1e3..ca298113 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -1172,6 +1172,8 @@ c_unparser::emit_module_init ()
   // PR10228: set up symbol table-related task finders.
   o->newline() << "#if defined(STP_NEED_VMA_TRACKER)";
   o->newline() << "_stp_sym_init();";
+  o->newline() << "#else";
+  o->newline() << "if (_stp_need_vma_tracker == 1) _stp_sym_init();";
   o->newline() << "#endif";
   // NB: we don't need per-_stp_module task_finders, since a single common one
   // set up in runtime/sym.c's _stp_sym_init() will scan through all _stp_modules.
@@ -5023,6 +5025,11 @@ emit_symbol_data_done (unwindsym_dump_context *ctx, systemtap_session& s)
     ctx->output << "0x" << hex << ctx->stp_kretprobe_trampoline_addr << dec
 		<< ";\n";
 
+  // Note when someone requested the task_finder.
+  ctx->output << "static char _stp_need_vma_tracker = "
+              << (s.task_finder_derived_probes ? "1" : "0")
+              << ";\n";
+
   // Some nonexistent modules may have been identified with "-d".  Note them.
   if (! s.suppress_warnings)
     for (set<string>::iterator it = ctx->undone_unwindsym_modules.begin();