[gold patch] Fix problem with placement of .tbss with scripts

[Cary Coutant]

> I think we can get the same results with code that is slightly simpler
> to understand by writing it like this:
>
>  // Sort PROGBITS before NOBITS.
>  if (os1->type() == elfcpp::SHT_PROGBITS && os2->type() == elfcpp::SHT_NOBITS)
>    return true;
>  if (os1->type() == elfcpp::SHT_NOBITS && os2->type() == elfcpp::SHT_PROGBITS)
>    return false;
>
>  // Sort PROGBITS TLS sections to the end, NOBITS TLS sections to the
>  // beginning.
>  bool tls1 = (os1->flags() & elfcpp::SHF_TLS) != 0;
>  bool tls2 = (os2->flags() & elfcpp::SHF_TLS) != 0;
>  if (tls1 != tls2)
>    return os1->type() == elfcpp::SHT_PROGBITS ? tls2 : tls1;

That looks easier to follow. Here's what I committed:


        * script-sections.cc (Sort_output_sections::operator()): Sort TLS
        sections before NOBITS sections.


Index: script-sections.cc
===================================================================
RCS file: /cvs/src/src/gold/script-sections.cc,v
retrieving revision 1.47
diff -u -p -r1.47 script-sections.cc
--- script-sections.cc  14 Dec 2010 19:03:30 -0000      1.47
+++ script-sections.cc  4 Jan 2011 20:59:34 -0000
@@ -1,6 +1,6 @@
 // script-sections.cc -- linker script SECTIONS for gold

-// Copyright 2008, 2009, 2010 Free Software Foundation, Inc.
+// Copyright 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
 // Written by Ian Lance Taylor <iant@google.com>.

 // This file is part of gold.
@@ -3586,17 +3586,18 @@ Sort_output_sections::operator()(const O
   if (os1->address() != os2->address())
     return os1->address() < os2->address();

-  // Sort TLS sections to the end.
+  // Sort PROGBITS before NOBITS.
+  bool nobits1 = os1->type() == elfcpp::SHT_NOBITS;
+  bool nobits2 = os2->type() == elfcpp::SHT_NOBITS;
+  if (nobits1 != nobits2)
+    return nobits2;
+
+  // Sort PROGBITS TLS sections to the end, NOBITS TLS sections to the
+  // beginning.
   bool tls1 = (os1->flags() & elfcpp::SHF_TLS) != 0;
   bool tls2 = (os2->flags() & elfcpp::SHF_TLS) != 0;
   if (tls1 != tls2)
-    return tls2;
-
-  // Sort PROGBITS before NOBITS.
-  if (os1->type() == elfcpp::SHT_PROGBITS && os2->type() == elfcpp::SHT_NOBITS)
-    return true;
-  if (os1->type() == elfcpp::SHT_NOBITS && os2->type() == elfcpp::SHT_PROGBITS)
-    return false;
+    return nobits1 ? tls1 : tls2;

   // Sort non-NOLOAD before NOLOAD.
   if (os1->is_noload() && !os2->is_noload())