PR11246 cont'd: Add options for cache control

--disable-cache : turn off all caching
--clean-cache   : clean up stale entries and then quit
--poison-cache  : force regeneration of items that would have hit the cache

These are undocumented for now, until we decide whether they are
generally useful.

* main.cxx (main): Parse the new options.
* session.h (systemtap_session): Add poison_cache; document the others.
* clean.cxx (clean_cache): No longer static.
  (get_stapconf_from_cache, get_script_from_cache): Respect poison.
* tapsets.cxx (tracepoint_builder::get_tracequery_module): Ditto.
  (dwarf_cast_expanding_visitor::filter_special_modules): Ditto.

1 files changed, 7 insertions, 3 deletions

diff --git a/cache.cxx b/cache.cxx
index 6b51f21c..13436439 100644
--- a/cache.cxx
+++ b/cache.cxx
@@ -42,8 +42,6 @@ struct cache_ent_info {
   void unlink() const;
 };
 
-static void clean_cache(systemtap_session& s);
-
 
 void
 add_stapconf_to_cache(systemtap_session& s)
@@ -101,6 +99,9 @@ add_script_to_cache(systemtap_session& s)
 bool
 get_stapconf_from_cache(systemtap_session& s)
 {
+  if (s.poison_cache)
+    return false;
+
   string stapconf_dest_path = s.tmpdir + "/" + s.stapconf_name;
   int fd_stapconf;
 
@@ -132,6 +133,9 @@ get_stapconf_from_cache(systemtap_session& s)
 bool
 get_script_from_cache(systemtap_session& s)
 {
+  if (s.poison_cache)
+    return false;
+
   string module_dest_path = s.tmpdir + "/" + s.module_name + ".ko";
   string c_src_path = s.hash_path;
   int fd_module, fd_c;
@@ -215,7 +219,7 @@ get_script_from_cache(systemtap_session& s)
 }
 
 
-static void
+void
 clean_cache(systemtap_session& s)
 {
   if (s.cache_path != "")