PowerPC gold assertion on missing global entry stub

PowerPC gold assertion on missing global entry stub

[Alan Modra]

Global entry stubs are used on ELFv2 to provide addresses for
functions not defined in a non-PIC executable but whose address is
taken, in much the same way as PLT stub code is used on other
targets to provide function addresses.  We don't want to insert a
global entry stub just because (bogus) debug info refers to the
address of a non-local function, but we also don't want gold to die.

	* powerpc.cc (Target_powerpc::Relocate::relocate): Don't assert
	on missing global entry stub due to bogus debug info.

diff --git a/gold/powerpc.cc b/gold/powerpc.cc
index fddf3fa..3d753b5 100644
--- a/gold/powerpc.cc
+++ b/gold/powerpc.cc
@@ -6836,8 +6836,11 @@ Target_powerpc<size, big_endian>::Relocate::relocate(
 	  && !is_branch_reloc(r_type))
 	{
 	  unsigned int off = target->glink_section()->find_global_entry(gsym);
-	  gold_assert(off != (unsigned int)-1);
-	  value = target->glink_section()->global_entry_address() + off;
+	  if (off != (unsigned int)-1)
+	    {
+	      value = target->glink_section()->global_entry_address() + off;
+	      has_stub_value = true;
+	    }
 	}
       else
 	{
@@ -6859,8 +6862,8 @@ Target_powerpc<size, big_endian>::Relocate::relocate(
 						  rela.get_r_addend());
 	  gold_assert(off != invalid_address);
 	  value = stub_table->stub_address() + off;
+	  has_stub_value = true;
 	}
-      has_stub_value = true;
     }
 
   if (r_type == elfcpp::R_POWERPC_GOT16

-- 
Alan Modra
Australia Development Lab, IBM

Re: PowerPC gold assertion on missing global entry stub

[Alan Modra]

On Tue, Apr 28, 2015 at 01:45:10PM +0930, Alan Modra wrote:
> 	* powerpc.cc (Target_powerpc::Relocate::relocate): Don't assert
> 	on missing global entry stub due to bogus debug info.

Completely removing the assert probably wasn't the best idea, so
reinstate it for allocated sections.  Also cope with debug info
potentially referring to a missing plt call stub.

And a tidy.  find_global_entry now returns an Address, so make temps
holding the return value of type Address, and compare against
invalid_address.

	* powerpc.cc (Target_powerpc::do_dynsym_value): Use Address rather
	than unsigned int for find_global_entry result temp.  Compare
	against invalid_address.
	(Target_powerpc::do_plt_address_for_global): Likewise.
	(Target_powerpc::Relocate::relocate): Likewise.  Don't assert
	on plt call stub existence for debug info.  Do assert for plt
	and global entry stub existence if an alloc section.

diff --git a/gold/powerpc.cc b/gold/powerpc.cc
index 3d753b5..9a0bd9d 100644
--- a/gold/powerpc.cc
+++ b/gold/powerpc.cc
@@ -6835,8 +6835,8 @@ Target_powerpc<size, big_endian>::Relocate::relocate(
 	  && !parameters->options().output_is_position_independent()
 	  && !is_branch_reloc(r_type))
 	{
-	  unsigned int off = target->glink_section()->find_global_entry(gsym);
-	  if (off != (unsigned int)-1)
+	  Address off = target->glink_section()->find_global_entry(gsym);
+	  if (off != invalid_address)
 	    {
 	      value = target->glink_section()->global_entry_address() + off;
 	      has_stub_value = true;
@@ -6852,18 +6852,26 @@ Target_powerpc<size, big_endian>::Relocate::relocate(
 	      if (target->stub_tables().size() != 0)
 		stub_table = target->stub_tables()[0];
 	    }
-	  gold_assert(stub_table != NULL);
-	  Address off;
-	  if (gsym != NULL)
-	    off = stub_table->find_plt_call_entry(object, gsym, r_type,
-						  rela.get_r_addend());
-	  else
-	    off = stub_table->find_plt_call_entry(object, r_sym, r_type,
-						  rela.get_r_addend());
-	  gold_assert(off != invalid_address);
-	  value = stub_table->stub_address() + off;
-	  has_stub_value = true;
+	  if (stub_table != NULL)
+	    {
+	      Address off;
+	      if (gsym != NULL)
+		off = stub_table->find_plt_call_entry(object, gsym, r_type,
+						      rela.get_r_addend());
+	      else
+		off = stub_table->find_plt_call_entry(object, r_sym, r_type,
+						      rela.get_r_addend());
+	      if (off != invalid_address)
+		{
+		  value = stub_table->stub_address() + off;
+		  has_stub_value = true;
+		}
+	    }
 	}
+      // We don't care too much about bogus debug references to
+      // non-local functions, but otherwise there had better be a plt
+      // call stub or global entry stub as appropriate.
+      gold_assert(has_stub_value || !(os->flags() & elfcpp::SHF_ALLOC));
     }
 
   if (r_type == elfcpp::R_POWERPC_GOT16
@@ -8232,8 +8240,8 @@ Target_powerpc<size, big_endian>::do_dynsym_value(const Symbol* gsym) const
     }
   else if (this->abiversion() >= 2)
     {
-      unsigned int off = this->glink_section()->find_global_entry(gsym);
-      if (off != (unsigned int)-1)
+      Address off = this->glink_section()->find_global_entry(gsym);
+      if (off != invalid_address)
 	return this->glink_section()->global_entry_address() + off;
     }
   gold_unreachable();
@@ -8282,8 +8290,8 @@ Target_powerpc<size, big_endian>::do_plt_address_for_global(
     }
   else if (this->abiversion() >= 2)
     {
-      unsigned int off = this->glink_section()->find_global_entry(gsym);
-      if (off != (unsigned int)-1)
+      Address off = this->glink_section()->find_global_entry(gsym);
+      if (off != invalid_address)
 	return this->glink_section()->global_entry_address() + off;
     }
   gold_unreachable();

-- 
Alan Modra
Australia Development Lab, IBM