PR22770: MIPS: Fix GOT page counter in multi-got links

The record_got_page_entry function records and updates the maximum
number of GOT page entries which may be required by an object. In the
case where an existing GOT page entry was expanded, only the entry
belonging to the master GOT would have its page count updated. This leaves
the entry belonging to the object GOT with the num_pages count of 1 it
was originally initialized with. Later on when GOTs are being merged in a
multi-got link, this causes the value of entry->num_pages in
add_got_page_entries to always be 1 and underestimates the number of pages
required for the new entry. This in turn leads to an assertion failure in
get_got_page_offset where we run out of pages.

Fix by not inserting Got_page_entrys into the object's GOT at all and
later on adding the total number of page entries recorded for the
object's GOT into the new merged GOT. This is safe because
got_page_entries_ is used for no other purpose in the object's GOT, and
page_gotno_ for the object's GOT should already be incremented by the correct
amount in record_got_page_entry. Remove Got_page_entry::num_pages which
is now unused.

gold/
2018-03-01  James Cowgill  <james.cowgill@mips.com>

	PR gold/22770
	* mips.cc (Mips_got_info::record_got_page_entry): Don't insert
	Got_page_entry for object's GOT.
	(Mips_got_info::add_got_page_entries): Add all pages from from's GOT.
	Rename to add_got_page_count.
	(Got_page_entry): Remove num_pages.

Gbp-Pq: Name pr22770-v3.patch

diff --git a/gold/mips.cc b/gold/mips.cc
index 543a23462f71c140809770f28d531ed2dec99210..b4de79b946f15336e5aa5fa98d2c10309f3d952b 100644 (file)
--- a/gold/mips.cc
+++ b/gold/mips.cc
@@ -631,11 +631,11 @@ struct Got_page_range
 struct Got_page_entry
 {
   Got_page_entry()
-    : object(NULL), symndx(-1U), ranges(NULL), num_pages(0)
+    : object(NULL), symndx(-1U), ranges(NULL)
   { }
 
   Got_page_entry(Object* object_, unsigned int symndx_)
-    : object(object_), symndx(symndx_), ranges(NULL), num_pages(0)
+    : object(object_), symndx(symndx_), ranges(NULL)
   { }
 
   // The input object that needs the GOT page entry.
@@ -644,8 +644,6 @@ struct Got_page_entry
   unsigned int symndx;
   // The ranges for this page entry.
   Got_page_range* ranges;
-  // The maximum number of page entries needed for RANGES.
-  unsigned int num_pages;
 };
 
 // Hash for Got_page_entry.
@@ -775,7 +773,7 @@ class Mips_got_info
 
   // Add FROM's GOT page entries.
   void
-  add_got_page_entries(Mips_got_info<size, big_endian>* from);
+  add_got_page_count(Mips_got_info<size, big_endian>* from);
 
   // Return GOT size.
   unsigned int
@@ -928,7 +926,7 @@ class Mips_got_info
   Global_got_entry_set global_got_symbols_;
   // A hash table holding GOT entries.
   Got_entry_set got_entries_;
-  // A hash table of GOT page entries.
+  // A hash table of GOT page entries (only used in master GOT).
   Got_page_entry_set got_page_entries_;
   // The offset of first GOT page entry for this GOT.
   unsigned int got_page_offset_start_;
@@ -5794,14 +5792,8 @@ Mips_got_info<size, big_endian>::record_got_page_entry(
   else
     this->got_page_entries_.insert(entry);
 
-  // Add the same entry to the OBJECT's GOT.
-  Got_page_entry* entry2 = NULL;
+  // Get the object's GOT, but we don't need to insert an entry here.
   Mips_got_info<size, big_endian>* g2 = object->get_or_create_got_info();
-  if (g2->got_page_entries_.find(entry) == g2->got_page_entries_.end())
-    {
-      entry2 = new Got_page_entry(*entry);
-      g2->got_page_entries_.insert(entry2);
-    }
 
   // Skip over ranges whose maximum extent cannot share a page entry
   // with ADDEND.
@@ -5821,9 +5813,6 @@ Mips_got_info<size, big_endian>::record_got_page_entry(
       range->max_addend = addend;
 
       *range_ptr = range;
-      ++entry->num_pages;
-      if (entry2 != NULL)
-        ++entry2->num_pages;
       ++this->page_gotno_;
       ++g2->page_gotno_;
       return;
@@ -5851,9 +5840,6 @@ Mips_got_info<size, big_endian>::record_got_page_entry(
   new_pages = range->get_max_pages();
   if (old_pages != new_pages)
     {
-      entry->num_pages += new_pages - old_pages;
-      if (entry2 != NULL)
-        entry2->num_pages += new_pages - old_pages;
       this->page_gotno_ += new_pages - old_pages;
       g2->page_gotno_ += new_pages - old_pages;
     }
@@ -6353,22 +6339,10 @@ Mips_got_info<size, big_endian>::add_got_entries(
 
 template<int size, bool big_endian>
 void
-Mips_got_info<size, big_endian>::add_got_page_entries(
+Mips_got_info<size, big_endian>::add_got_page_count(
     Mips_got_info<size, big_endian>* from)
 {
-  for (typename Got_page_entry_set::iterator
-       p = from->got_page_entries_.begin();
-       p != from->got_page_entries_.end();
-       ++p)
-    {
-      Got_page_entry* entry = *p;
-      if (this->got_page_entries_.find(entry) == this->got_page_entries_.end())
-        {
-          Got_page_entry* entry2 = new Got_page_entry(*entry);
-          this->got_page_entries_.insert(entry2);
-          this->page_gotno_ += entry->num_pages;
-        }
-    }
+  this->page_gotno_ += from->page_gotno_;
 }
 
 // Mips_output_data_got methods.
@@ -6569,7 +6543,7 @@ Mips_output_data_got<size, big_endian>::merge_got_with(
 
   // Transfer the object's GOT information from FROM to TO.
   to->add_got_entries(from);
-  to->add_got_page_entries(from);
+  to->add_got_page_count(from);
 
   // Record that OBJECT should use output GOT TO.
   object->set_got_info(to);