Implement SORT_BY_INIT_PRIORITY.

2016-06-28  Igor Kudrin  <ikudrin@accesssoftek.com>

gold/
	PR gold/18098
	* script-c.h (Sort_wildcard): Add SORT_WILDCARD_BY_INIT_PRIORITY.
	* script-sections.cc (Input_section_sorter::get_init_priority): New method.
	(Input_section_sorter::operator()): Handle SORT_WILDCARD_BY_INIT_PRIORITY.
	(Output_section_element_input::print): Likewise.
	* script.cc (script_keyword_parsecodes): Add entry SORT_BY_INIT_PRIORITY.
	* yyscript.y (SORT_BY_INIT_PRIORITY): New token.
	(wildcard_section): Handle SORT_BY_INIT_PRIORITY.

	* testsuite/Makefile.am (script_test_14): New test.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/script_test_14.s: New test source file.
	* testsuite/script_test_14.sh: New test script.
	* testsuite/script_test_14.t: New test linker script.

1 files changed, 56 insertions, 1 deletions

diff --git a/gold/script-sections.cc b/gold/script-sections.cc
index ef82953..96c68de 100644
--- a/gold/script-sections.cc
+++ b/gold/script-sections.cc
@@ -1524,18 +1524,69 @@ class Input_section_sorter
   operator()(const Input_section_info&, const Input_section_info&) const;
 
  private:
+  static unsigned long
+  get_init_priority(const char*);
+
   Sort_wildcard filename_sort_;
   Sort_wildcard section_sort_;
 };
 
+// Return a relative priority of the section with the specified NAME
+// (a lower value meand a higher priority), or 0 if it should be compared
+// with others as strings.
+// The implementation of this function is copied from ld/ldlang.c.
+
+unsigned long
+Input_section_sorter::get_init_priority(const char* name)
+{
+  char* end;
+  unsigned long init_priority;
+
+  // GCC uses the following section names for the init_priority
+  // attribute with numerical values 101 and 65535 inclusive. A
+  // lower value means a higher priority.
+  // 
+  // 1: .init_array.NNNN/.fini_array.NNNN: Where NNNN is the
+  //    decimal numerical value of the init_priority attribute.
+  //    The order of execution in .init_array is forward and
+  //    .fini_array is backward.
+  // 2: .ctors.NNNN/.dtors.NNNN: Where NNNN is 65535 minus the
+  //    decimal numerical value of the init_priority attribute.
+  //    The order of execution in .ctors is backward and .dtors
+  //    is forward.
+
+  if (strncmp(name, ".init_array.", 12) == 0
+      || strncmp(name, ".fini_array.", 12) == 0)
+    {
+      init_priority = strtoul(name + 12, &end, 10);
+      return *end ? 0 : init_priority;
+    }
+  else if (strncmp(name, ".ctors.", 7) == 0
+	   || strncmp(name, ".dtors.", 7) == 0)
+    {
+      init_priority = strtoul(name + 7, &end, 10);
+      return *end ? 0 : 65535 - init_priority;
+    }
+
+  return 0;
+}
+
 bool
 Input_section_sorter::operator()(const Input_section_info& isi1,
 				 const Input_section_info& isi2) const
 {
+  if (this->section_sort_ == SORT_WILDCARD_BY_INIT_PRIORITY)
+    {
+      unsigned long ip1 = get_init_priority(isi1.section_name().c_str());
+      unsigned long ip2 = get_init_priority(isi2.section_name().c_str());
+      if (ip1 != 0 && ip2 != 0 && ip1 != ip2)
+	return ip1 < ip2;
+    }
   if (this->section_sort_ == SORT_WILDCARD_BY_NAME
       || this->section_sort_ == SORT_WILDCARD_BY_NAME_BY_ALIGNMENT
       || (this->section_sort_ == SORT_WILDCARD_BY_ALIGNMENT_BY_NAME
-	  && isi1.addralign() == isi2.addralign()))
+	  && isi1.addralign() == isi2.addralign())
+      || this->section_sort_ == SORT_WILDCARD_BY_INIT_PRIORITY)
     {
       if (isi1.section_name() != isi2.section_name())
 	return isi1.section_name() < isi2.section_name();
@@ -1827,6 +1878,10 @@ Output_section_element_input::print(FILE* f) const
 	      fprintf(f, "SORT_BY_ALIGNMENT(SORT_BY_NAME(");
 	      close_parens = 2;
 	      break;
+	    case SORT_WILDCARD_BY_INIT_PRIORITY:
+	      fprintf(f, "SORT_BY_INIT_PRIORITY(");
+	      close_parens = 1;
+	      break;
 	    default:
 	      gold_unreachable();
 	    }