* layout.cc (Free_list::allocate): Provide guarantee of minimum

	remaining hole size when allocating.
	(Layout::make_output_section): Set fill methods for debug sections.
	* layout.h (Free_list::Free_list_node): Move from private to
	public.
	(Free_list::set_min_hole_size): New function.
	(Free_list::begin, Free_list::end): New functions.
	(Free_list::min_hole_): New data member.
	* output.cc: Include dwarf.h.
	(Output_fill_debug_info::do_minimum_hole_size): New function.
	(Output_fill_debug_info::do_write): New function.
	(Output_fill_debug_line::do_minimum_hole_size): New function.
	(Output_fill_debug_line::do_write): New function.
	(Output_section::Output_section): Initialize new data member.
	(Output_section::set_final_data_size): Ensure patch space is larger
	than minimum hole size.
	(Output_section::do_write): Fill holes in debug sections.
	* output.h (Output_fill): New class.
	(Output_fill_debug_info): New class.
	(Output_fill_debug_line): New class.
	(Output_section::set_free_space_fill): New function.
	(Output_section::free_space_fill_): New data member.
	* testsuite/Makefile.am (incremental_test_3): Add
	--incremental-patch option.
	(incremental_test_4): Likewise.
	(incremental_test_5): Likewise.
	(incremental_test_6): Likewise.
	(incremental_copy_test): Likewise.
	(incremental_common_test_1): Likewise.
	* testsuite/Makefile.in: Regenerate.

1 files changed, 23 insertions, 5 deletions

diff --git a/gold/layout.cc b/gold/layout.cc
index 44c2e183e82..afb5b6af041 100644
--- a/gold/layout.cc
+++ b/gold/layout.cc
@@ -162,6 +162,11 @@ Free_list::allocate(off_t len, uint64_t align, off_t minoff)
 
   ++Free_list::num_allocates;
 
+  // We usually want to drop free chunks smaller than 4 bytes.
+  // If we need to guarantee a minimum hole size, though, we need
+  // to keep track of all free chunks.
+  const int fuzz = this->min_hole_ > 0 ? 0 : 3;
+
   for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
     {
       ++Free_list::num_allocate_visits;
@@ -173,13 +178,13 @@ Free_list::allocate(off_t len, uint64_t align, off_t minoff)
 	  this->length_ = end;
 	  p->end_ = end;
 	}
-      if (end <= p->end_)
+      if (end == p->end_ || (end <= p->end_ - this->min_hole_))
 	{
-	  if (p->start_ + 3 >= start && p->end_ <= end + 3)
+	  if (p->start_ + fuzz >= start && p->end_ <= end + fuzz)
 	    this->list_.erase(p);
-	  else if (p->start_ + 3 >= start)
+	  else if (p->start_ + fuzz >= start)
 	    p->start_ = end;
-	  else if (p->end_ <= end + 3)
+	  else if (p->end_ <= end + fuzz)
 	    p->end_ = start;
 	  else
 	    {
@@ -1440,7 +1445,20 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
       && strcmp(name, ".ctors") != 0
       && strcmp(name, ".dtors") != 0
       && strcmp(name, ".jcr") != 0)
-    os->set_is_patch_space_allowed();
+    {
+      os->set_is_patch_space_allowed();
+
+      // Certain sections require "holes" to be filled with
+      // specific fill patterns.  These fill patterns may have
+      // a minimum size, so we must prevent allocations from the
+      // free list that leave a hole smaller than the minimum.
+      if (strcmp(name, ".debug_info") == 0)
+        os->set_free_space_fill(new Output_fill_debug_info(false));
+      else if (strcmp(name, ".debug_types") == 0)
+        os->set_free_space_fill(new Output_fill_debug_info(true));
+      else if (strcmp(name, ".debug_line") == 0)
+        os->set_free_space_fill(new Output_fill_debug_line());
+    }
 
   // If we have already attached the sections to segments, then we
   // need to attach this one now.  This happens for sections created