[gold patch] Fix incremental update problems with shared objects and versioned symbols

[Cary Coutant]

This patch fixes a crash that can happen when all the objects that
reference a PLT symbol are replaced during an incremental update
(missing test for NULL). That fix exposed another where if a changed
shared object contains a reference to a versioned symbol that is
defined in an unchanged shared object, we cannot resolve the reference
because the incremental info does not (yet) store version information.
Adding version support is for a later patch; for now, I ignore
incoming version references during an incremental update.

OK to commit?

-cary


	* gold/incremental.cc (Sized_incremental_binary::do_process_got_plt):
	Check for NULL.
	* gold/symtab.cc (Symbol_table::add_from_relobj): Ignore version
	symbols during incremental update.
	(Symbol_table::add_from_dynobj): Likewise.
-------------- next part --------------
2011-09-27  Cary Coutant  <ccoutant@google.com>

	* gold/incremental.cc (Sized_incremental_binary::do_process_got_plt):
	Check for NULL.
	* gold/symtab.cc (Symbol_table::add_from_relobj): Ignore version
	symbols during incremental update.
	(Symbol_table::add_from_dynobj): Likewise.


commit ef3c2022d3a23abd0ab2630570807897c8122c7f
Author: Cary Coutant <ccoutant@google.com>
Date:   Tue Sep 27 18:35:17 2011 -0700

    Fix crash when shared lib is changed; fix undef versioned symbol.

diff --git a/gold/incremental.cc b/gold/incremental.cc
index b422827..cbf6fba 100644
--- a/gold/incremental.cc
+++ b/gold/incremental.cc
@@ -685,7 +685,7 @@ Sized_incremental_binary<size, big_endian>::do_process_got_plt(
       gold_assert(plt_desc >= first_global && plt_desc < symtab_count);
       Symbol* sym = this->global_symbol(plt_desc - first_global);
       // Add the PLT entry only if the symbol is still referenced.
-      if (sym->in_reg())
+      if (sym != NULL && sym->in_reg())
 	{
 	  gold_debug(DEBUG_INCREMENTAL,
 		     "PLT entry %d: %s",
diff --git a/gold/symtab.cc b/gold/symtab.cc
index ff6ff84..497cc82 100644
--- a/gold/symtab.cc
+++ b/gold/symtab.cc
@@ -1143,6 +1143,14 @@ Symbol_table::add_from_relobj(
       bool is_default_version = false;
       bool is_forced_local = false;
 
+      // FIXME: For incremental links, we don't store version information,
+      // so we need to ignore version symbols for now.
+      if (parameters->incremental_update() && ver != NULL)
+	{
+	  namelen = ver - name;
+	  ver = NULL;
+	}
+
       if (ver != NULL)
         {
           // The symbol name is of the form foo@VERSION or foo@@VERSION
@@ -1346,6 +1354,11 @@ Symbol_table::add_from_dynobj(
       return;
     }
 
+  // FIXME: For incremental links, we don't store version information,
+  // so we need to ignore version symbols for now.
+  if (parameters->incremental_update())
+    versym = NULL;
+
   if (versym != NULL && versym_size / 2 < count)
     {
       dynobj->error(_("too few symbol versions"));