PR11015 Support shared library reloading (in different processes)

* runtime/task_finder_vma.c (stap_remove_vma_map_info): Return negative
  status on failure.
  (stap_find_vma_map_info): Likewise.
  (stap_find_vma_map_info_user): New function.
  (stap_drop_vma_maps): New function.
* runtime/sym.h (addr): Renamed to static_addr, to store addresses for
  sections which are always mapped at the same address.
  (_stp_module_relocate): Add extra struct task_struct *tsk argument.
* runtime/sym.c (_stp_tf_exec_cb): New callback, calls stap_drop_vma_maps.
  (_stp_tf_mmap_cb): Don't store address in module.section, but call
  stap_add_vma_map_info() per tsk->group_leader for matched module.
  Don't register empty/null modules.
  (_stp_module_relocate): Take extra struct task_struct *tsk argument,
  cache last tsk used. Only use section->static_addr for none dynamic
  modules. Use stap_find_vma_map_info_user() to locate dynamic modules.
  (_stp_mod_sec_lookup): Add extra argument unsigned long *rel_addr to
  optionally store relative address when module/section found.
  (_stp_kallsyms_lookup): Use _stp_mod_sec_lookup to find relative address.
  (_stp_sym_init): Register _stp_tf_exec_cb in stap_task_finder_target.
  Add error check to see if task finder could be initialized.
* dwflpp.cxx (emit_address): Pass NULL for kernel/modules and current for
  user tasks to _stp_module_relocate.
* runtime/transport/symbols.c (_stp_do_relocation): Set new static_addr
  _stp_section field.
* runtime/unwind.c (adjustStartLoc): Take new struct task_struct *tsk
  argument and pass to stap_find_vma_map_info_user and _stp_module_relocate
  to find adjusted addr.
  (_stp_search_unwind_hdr): Pass through struct task_struct *tsk.
  (unwind_frame): Likewise.
* tapset/context-symbols.stp (probemod): Add NULL to _stp_mod_sec_lookup
  call to indicate we aren't interested in relative address.
* tapsets.cxx (dwarf_derived_probe_group::emit_module_init): Pass NULL to
  _stp_module_relocate to indicate kernel/module address.

1 files changed, 3 insertions, 3 deletions

diff --git a/dwflpp.cxx b/dwflpp.cxx
index d3cecc44..4fb0d54e 100644
--- a/dwflpp.cxx
+++ b/dwflpp.cxx
@@ -1523,7 +1523,7 @@ dwflpp::emit_address (struct obstack *pool, Dwarf_Addr address)
           // This gives us the module name, and section name within the
           // module, for a kernel module (or other ET_REL module object).
           obstack_printf (pool, "({ unsigned long addr = 0; ");
-          obstack_printf (pool, "addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 "); ",
+          obstack_printf (pool, "addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 ", NULL); ",
                           modname, secname, reloc_address);
           obstack_printf (pool, "addr; })");
         }
@@ -1537,7 +1537,7 @@ dwflpp::emit_address (struct obstack *pool, Dwarf_Addr address)
           // kernel will never move after being loaded (unlike modules and
           // user-space dynamic share libraries).
           obstack_printf (pool, "({ static unsigned long addr = 0; ");
-          obstack_printf (pool, "if (addr==0) addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 "); ",
+          obstack_printf (pool, "if (addr==0) addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 ", NULL); ",
                           modname, secname, address); // PR10000 NB: not reloc_address
           obstack_printf (pool, "addr; })");
         }
@@ -1545,7 +1545,7 @@ dwflpp::emit_address (struct obstack *pool, Dwarf_Addr address)
         {
           enable_task_finder (sess);
           obstack_printf (pool, "({ unsigned long addr = 0; ");
-          obstack_printf (pool, "addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 "); ",
+          obstack_printf (pool, "addr = _stp_module_relocate (\"%s\",\"%s\",%#" PRIx64 ", current); ",
                           modname, ".dynamic", reloc_address);
           obstack_printf (pool, "addr; })");
         }