Get .probes section through dwarf debuginfo file if necessary.

* tapsets.cxx (dwarf_builder::build): Add some comments, verbose log
  messages and get Elf through dwarf_getelf if it exists before searching
  for .probes section.

diff --git a/tapsets.cxx b/tapsets.cxx
index ac43a222e3c8c8f96894077caf51670edbbc30dd..0e419e961e41f6be832b36b2a3c88989370efa91 100644 (file)
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -5617,6 +5617,9 @@ dwarf_builder::build(systemtap_session & sess,
         dw = user_dw[module_name];
     }
 
+  if (sess.verbose > 3)
+    clog << "dwarf_builder::build for " << module_name << endl;
+
   if (((probe_point::component*)(location->components[1]))->functor == TOK_MARK)
   {
     enum probe_types       
@@ -5628,9 +5631,13 @@ dwarf_builder::build(systemtap_session & sess,
 
     int probe_type = dwarf_no_probes;
     string probe_name = (char*) location->components[1]->arg->tok->content.c_str();
+    if (sess.verbose > 3)
+      clog << "TOK_MARK: " << probe_name << endl;
+
     __uint64_t probe_arg = 0;
     Dwarf_Addr bias;
-    Elf* elf = dwfl_module_getelf (dw->module, &bias);
+    Elf* elf = (dwarf_getelf (dwfl_module_getdwarf (dw->module, &bias))
+               ?: dwfl_module_getelf (dw->module, &bias));
     size_t shstrndx;
     Elf_Scn *probe_scn = NULL;
 
@@ -5651,18 +5658,31 @@ dwarf_builder::build(systemtap_session & sess,
          }
       }
     
+    // We got our .probes section, extract data.
     if (probe_type == probes_and_dwarf)
       {
+       if (sess.verbose > 3)
+         clog << "probe_type == probes_and_dwarf, use statement addr" << endl;
+ 
        Elf_Data *pdata = elf_getdata_rawchunk (elf, shdr->sh_offset, shdr->sh_size, ELF_T_BYTE);
        assert (pdata != NULL);
        size_t probe_scn_offset = 0;
        size_t probe_scn_addr = shdr->sh_addr;
+        if (sess.verbose > 4)
+         clog << "got .probes elf scn_addr@0x" << probe_scn_addr << dec
+              << ", size: " << pdata->d_size << endl;
        while (probe_scn_offset < pdata->d_size)
          {
            const int stap_sentinel = 0x31425250;
            probe_type = *((int*)((char*)pdata->d_buf + probe_scn_offset));
            if (probe_type != stap_sentinel)
              {
+               // Unless this is a mangled .probes section, this happens
+               // because the name of the probe comes first, followed by
+               // the sentinel.
+               if (sess.verbose > 5)
+                 clog << "got unknown probe_type: 0x" << hex << probe_type
+                      << dec << endl;
                probe_scn_offset += sizeof(int);
                continue;
              }
@@ -5675,6 +5695,10 @@ dwarf_builder::build(systemtap_session & sess,
            if (probe_scn_offset % (sizeof(__uint64_t)))
              probe_scn_offset += sizeof(__uint64_t) - (probe_scn_offset % sizeof(__uint64_t));
            probe_arg = *((__uint64_t*)((char*)pdata->d_buf + probe_scn_offset));
+           if (sess.verbose > 4)
+             clog << "saw .probes " << probe_name
+                  << "@0x" << hex << probe_arg << dec << endl;
+    
            if (probe_scn_offset % (sizeof(__uint64_t)*2))
              probe_scn_offset = (probe_scn_offset + sizeof(__uint64_t)*2) - (probe_scn_offset % (sizeof(__uint64_t)*2));
            if ((strcmp (location->components[1]->arg->tok->content.c_str(),
@@ -5684,6 +5708,9 @@ dwarf_builder::build(systemtap_session & sess,
                    (probe_name.c_str(),
                     location->components[1]->arg->tok->content.c_str())))
              {
+               if (sess.verbose > 3)
+                 clog << "found probe_name" << probe_name << " at 0x"
+                      << hex << probe_arg << dec << endl;
              }
            else
              continue;
@@ -5692,6 +5719,10 @@ dwarf_builder::build(systemtap_session & sess,
            location->components[1]->arg = new literal_number((long)probe_arg);
            location->components[1]->arg->tok = sv_tok;
            ((literal_map_t&)parameters)[TOK_STATEMENT] = location->components[1]->arg;
+
+           if (sess.verbose > 3)
+             clog << "probe_type == probes_and_dwarf, use statement addr: 0x"
+                  << hex << probe_arg << dec << endl;
            
            dwarf_query q(sess, base, location, *dw, parameters, finished_results);
            q.has_mark = true;
@@ -5714,8 +5745,15 @@ dwarf_builder::build(systemtap_session & sess,
        location->components[2]->arg = new literal_string("_stapprobe1_" + probe_name);
        ((literal_map_t&)parameters).erase(TOK_MARK);
        ((literal_map_t&)parameters).insert(pair<string,literal*>(TOK_LABEL, location->components[2]->arg));
+
+       if (sess.verbose > 3)
+         clog << "probe_type == dwarf_no_probes, use label name: "
+              << "_stapprobe1_" << probe_name << endl;
       }
 
+    else if (sess.verbose > 3)
+      clog << "probe_type == probes_no_dwarf" << endl;
+
     dw->module = 0;
   }