[patch] .statement("function@file.c+5")

[Stan Cox <scox at redhat dot com>]

This supports a relative line offset for .statement.  So for example:
 .statement("function@file.c:135") would be line 135 of function in
file.c
 .statement("function@file.c+3") would be function entry line + 3 in
file.c 

So for 2.6.24.5-85.fc8:
kernel.statement("bio_init@fs/bio.c:135")
kernel.statement("bio_init@fs/bio.c+3")
yield the same thing.

A very simple example:
probe kernel.statement("bio_init@fs/bio.c+3") {
  printf ("%s -> %s\n", thread_indent(1), probefunc())
  print_stack(backtrace())
}
probe timer.ms(2000) {
  exit ()
}

yields:
  5358 hald-addon-stor(2437):     -> bio_init
 0xffffffff810c24eb : bio_init+0x19/0x21
 0xffffffff810c2521 : bio_alloc_bioset+0x2e/0xd9
 0xffffffff810c2619 : bio_alloc+0x10/0x20
 0xffffffff810c2666 : bio_map_kern+0x3d/0x103
 0xffffffff81116e2b : blk_rq_map_kern+0x2f/0x84
 0xffffffff88059413 : scsi_execute+0x57/0xe7 [scsi_mod]
 0x00000ffffffff880

(Currently working on test cases.)

/work/scox/systemtap/src /work/scox/systemtap/bld/x86_64-redhat-linux /work/scox/stap
diff --git a/ChangeLog b/ChangeLog
index 313968d..3a50a1b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2008-06-06  Stan Cox  <scox@redhat.com>
+
+	* tapsets.cxx (dwflpp::iterate_over_srcfile_lines): 
+	Add parameter line_type_relative.  
+	(enum line_t): New.
+	(dwarf_query::line_type): New.
+	(dwarf_query::parse_function_spec): Set line_type.
+
 2008-05-29  Ananth N Mavinakayanahalli <ananth@in.ibm.com>
 
 	PR 6563
diff --git a/tapsets.cxx b/tapsets.cxx
index 151a1c4..b986b2e 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -1148,6 +1148,7 @@ struct dwflpp
   void iterate_over_srcfile_lines (char const * srcfile,
 				   int lineno,
 				   bool need_single_match,
+				   bool line_type_relative,
 				   void (* callback) (Dwarf_Line * line, void * arg),
 				   void *data)
   {
@@ -1157,6 +1158,20 @@ struct dwflpp
 
     get_module_dwarf();
 
+    if (line_type_relative) 
+      {
+	Dwarf_Addr addr;
+	Dwarf_Line *line;
+	int line_number;
+	int errno;
+	
+	dwarf_assert ("dwarf_entrypc", dwarf_entrypc (this->function, &addr));
+	line = dwarf_getsrc_die (this->cu, addr);
+	dwarf_assert ("dwarf_getsrc_die", line == NULL);
+	dwarf_assert ("dwarf_lineno", dwarf_lineno (line, &line_number));
+	lineno += line_number;
+      }
+
     dwarf_assert ("dwarf_getsrc_file",
 		  dwarf_getsrc_file (module_dwarf,
 				     srcfile, lineno, 0,
@@ -2341,6 +2356,8 @@ base_query::get_number_param(map<string, literal *> const & params,
 }
 
 
+enum line_t { ABSOLUTE, RELATIVE };
+
 struct dwarf_query : public base_query
 {
   dwarf_query(systemtap_session & sess,
@@ -2407,6 +2424,7 @@ struct dwarf_query : public base_query
   function_spec_type spec_type;
   string function;
   string file;
+  line_t line_type;
   int line;
   bool query_done;	// Found exact match
 
@@ -2878,7 +2896,7 @@ dwarf_query::parse_function_spec(string & spec)
 
   while (i != e && *i != '@')
     {
-      if (*i == ':')
+      if (*i == ':' || *i == '+')
 	goto bad;
       function += *i++;
     }
@@ -2895,8 +2913,12 @@ dwarf_query::parse_function_spec(string & spec)
   if (i++ == e)
     goto bad;
 
-  while (i != e && *i != ':')
+  while (i != e && *i != ':' && *i != '+')
     file += *i++;
+  if (*i == ':') 
+    line_type = ABSOLUTE;
+  else if (*i == '+')
+    line_type = RELATIVE;
 
   if (i == e)
     {
@@ -3500,7 +3522,7 @@ query_cu (Dwarf_Die * cudie, void * arg)
 	      for (set<char const *>::const_iterator i = q->filtered_srcfiles.begin();
 		   i != q->filtered_srcfiles.end(); ++i)
 		q->dw.iterate_over_srcfile_lines (*i, q->line, q->has_statement_str,
-						  query_srcfile_line, q);
+						  q->line_type, query_srcfile_line, q);
 	    }
 	  else
 	    {