Improve ODR checking in gold.

gold/
	* debug.h (DEBUG_LOCATION): New.
	(DEBUG_ALL): Include DEBUG_LOCATION.
	(debug_string_to_enum): Add DEBUG_LOCATION.
	* dwarf_reader.cc (Sized_dwarf_line_info::read_lines): Fix debug
	output to print correct context.
	(Sized_dwarf_line_info::do_addr2line): Add debug output. Return
	up to 4 more locations at the beginning of the function.
	* symtab.cc (Symbol_table::detect_odr_violations): Get canonical
	result before sorting list of line numbers.
	* testsuite/debug_msg.sh: Allow range of line numbers for
	canonical results on optimized code.

1 files changed, 7 insertions, 4 deletions

diff --git a/gold/symtab.cc b/gold/symtab.cc
index 045327ac310..88e932268ed 100644
--- a/gold/symtab.cc
+++ b/gold/symtab.cc
@@ -3336,8 +3336,11 @@ Symbol_table::detect_odr_violations(const Task* task,
           first_object_name = locs->object->name();
           first_object_linenos = this->linenos_from_loc(task, *locs);
         }
+      if (first_object_linenos.empty())
+	continue;
 
       // Sort by Odr_violation_compare to make std::set_intersection work.
+      std::string first_object_canonical_result = first_object_linenos.back();
       std::sort(first_object_linenos.begin(), first_object_linenos.end(),
                 Odr_violation_compare());
 
@@ -3349,6 +3352,8 @@ Symbol_table::detect_odr_violations(const Task* task,
           if (linenos.empty())
             continue;
           // Sort by Odr_violation_compare to make std::set_intersection work.
+          gold_assert(!linenos.empty());
+          std::string second_object_canonical_result = linenos.back();
           std::sort(linenos.begin(), linenos.end(), Odr_violation_compare());
 
           Check_intersection intersection_result =
@@ -3367,13 +3372,11 @@ Symbol_table::detect_odr_violations(const Task* task,
               // which may not be the location we expect to intersect
               // with another definition.  We could print the whole
               // set of locations, but that seems too verbose.
-              gold_assert(!first_object_linenos.empty());
-              gold_assert(!linenos.empty());
               fprintf(stderr, _("  %s from %s\n"),
-                      first_object_linenos[0].c_str(),
+                      first_object_canonical_result.c_str(),
                       first_object_name.c_str());
               fprintf(stderr, _("  %s from %s\n"),
-                      linenos[0].c_str(),
+                      second_object_canonical_result.c_str(),
                       locs->object->name().c_str());
               // Only print one broken pair, to avoid needing to
               // compare against a list of the disjoint definition