Fix "overflow in PLT unwind data" warning

When linking statically, it's possible to hit this warning with IFUNC
or very large executables, due to .glink being unused.

	* powerpc.cc (do_plt_fde_location): Handle zero length .glink.
	Compare FDE contents with DW_CFA_nop rather than 0.

diff --git a/gold/ChangeLog b/gold/ChangeLog
index 6d1c14b..f0ee1f7 100644 (file)
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,8 @@
+2014-05-15  Alan Modra  <amodra@gmail.com>
+
+       * powerpc.cc (do_plt_fde_location): Handle zero length .glink.
+       Compare FDE contents with DW_CFA_nop rather than 0.
+
 2014-05-13  Sriraman Tallam  <tmsriram@google.com>
 
        * symtab.h (may_need_copy_reloc): Remove check for position independent
@@ -15,7 +20,7 @@
        * testsuite/pie_copyrelocs_test.cc: New file.
        * testsuite/pie_copyrelocs_shared_test.cc: New file.
        * Makefile.am (pie_copyrelocs_test): New test.
-       * Makefile.in: Regenerate.  
+       * Makefile.in: Regenerate.
 
 2014-05-08  Martin Liška  <mliska@suse.cz>
 
@@ -45,37 +50,37 @@
        class.
 
 2014-05-05  Cary Coutant  <ccoutant@google.com>
-        
+
        * gdb-index.cc (Gdb_index_info_reader): Don't complain about language
        if we have pubnames/pubtypes.
 
 2014-05-02  Cary Coutant  <ccoutant@google.com>
 
-       * defstd.cc (in_segment): Define __ehdr_start here...
-       * layout.cc (Layout::finalize): ...Instead of here.  Set the
-       output segment when known.
-       * resolve.cc (Symbol::override_base_with_special): Remember
-       the original binding.
-       * symtab.cc (Symbol::set_output_segment): New function.
-       (Symbol::set_undefined): New function.
-       * symtab.h (Symbol::is_weak_undefined): Check original undef
-       binding.
-       (Symbol::is_strong_undefined): New function.
-       (Symbol::set_output_segment): New function.
-       (Symbol::set_undefined): New function.
-       * target-reloc.h (is_strong_undefined): Remove.
-       (issue_undefined_symbol_error): Call Symbol::is_weak_undefined.
-       Check for hidden undefs.
-       (relocate_section): Call Symbol::is_strong_undefined.
-    
-       * testsuite/Makefile.am (ehdr_start_test_1)
-       (ehdr_start_test_2, ehdr_start_test_3)
-       (ehdr_start_test_4, ehdr_start_test_5): New test cases.
-       * testsuite/Makefile.in: Regenerate.
-       * testsuite/ehdr_start_def.cc: New source file.
-       * testsuite/ehdr_start_test.cc: New source file.
-       * testsuite/ehdr_start_test.t: New linker script.
-       * testsuite/ehdr_start_test_4.sh: New shell script.
+       * defstd.cc (in_segment): Define __ehdr_start here...
+       * layout.cc (Layout::finalize): ...Instead of here.  Set the
+       output segment when known.
+       * resolve.cc (Symbol::override_base_with_special): Remember
+       the original binding.
+       * symtab.cc (Symbol::set_output_segment): New function.
+       (Symbol::set_undefined): New function.
+       * symtab.h (Symbol::is_weak_undefined): Check original undef
+       binding.
+       (Symbol::is_strong_undefined): New function.
+       (Symbol::set_output_segment): New function.
+       (Symbol::set_undefined): New function.
+       * target-reloc.h (is_strong_undefined): Remove.
+       (issue_undefined_symbol_error): Call Symbol::is_weak_undefined.
+       Check for hidden undefs.
+       (relocate_section): Call Symbol::is_strong_undefined.
+
+       * testsuite/Makefile.am (ehdr_start_test_1)
+       (ehdr_start_test_2, ehdr_start_test_3)
+       (ehdr_start_test_4, ehdr_start_test_5): New test cases.
+       * testsuite/Makefile.in: Regenerate.
+       * testsuite/ehdr_start_def.cc: New source file.
+       * testsuite/ehdr_start_test.cc: New source file.
+       * testsuite/ehdr_start_test.t: New linker script.
+       * testsuite/ehdr_start_test_4.sh: New shell script.
 
 2014-04-23  Cary Coutant  <ccoutant@google.com>
 
@@ -135,7 +140,7 @@
        (Target::do_adjust_dyn_symbol): New function.
 
 2014-03-10  Sasa Stankovic  <Sasa.Stankovic@imgtec.com>
-  
+
        * output.cc (Output_data_dynamic::Dynamic_entry::write):
        Get the value of DYNAMIC_CUSTOM dynamic entry.
        * output.h (Output_data_dynamic::add_custom): New function.
@@ -208,7 +213,7 @@
        Check for is_strong_undefined.
 
 2014-02-05  Cary Coutant  <ccoutant@google.com>
-    
+
        Fix problems with the --dynamic-list option.
 
        PR gold/13577
@@ -221,11 +226,11 @@
        (General_options::have_dynamic_list_): New data member.
        * symtab.h (Symbol::is_preemptible): Handle --dynamic-list
        correctly.
-   
+
        PR gold/16530
        * symtab.cc (Symbol_table::add_from_relobj): If symbol is named
        in --dynamic-list, mark it.
-   
+
        * testsuite/Makefile.am (gc_dynamic_list_test.sh): New test case.
        (dynamic_list_2): New test case.
        * testsuite/Makefile.in: Regenerate.

diff --git a/gold/powerpc.cc b/gold/powerpc.cc
index b9ee86e..e59c319 100644 (file)
--- a/gold/powerpc.cc
+++ b/gold/powerpc.cc
@@ -2851,7 +2851,21 @@ Target_powerpc<size, big_endian>::do_plt_fde_location(const Output_data* plt,
   if (plt == this->glink_)
     {
       // See Output_data_glink::do_write() for glink contents.
-      if (size == 64)
+      if (len == 0)
+       {
+         gold_assert(parameters->doing_static_link());
+         // Static linking may need stubs, to support ifunc and long
+         // branches.  We need to create an output section for
+         // .eh_frame early in the link process, to have a place to
+         // attach stub .eh_frame info.  We also need to have
+         // registered a CIE that matches the stub CIE.  Both of
+         // these requirements are satisfied by creating an FDE and
+         // CIE for .glink, even though static linking will leave
+         // .glink zero length.
+         // ??? Hopefully generating an FDE with a zero address range
+         // won't confuse anything that consumes .eh_frame info.
+       }
+      else if (size == 64)
        {
          // There is one word before __glink_PLTresolve
          address += 8;
@@ -2863,7 +2877,7 @@ Target_powerpc<size, big_endian>::do_plt_fde_location(const Output_data* plt,
          // The first covers the branch table, the second
          // __glink_PLTresolve at the end of glink.
          off_t resolve_size = this->glink_->pltresolve_size;
-         if (oview[9] == 0)
+         if (oview[9] == elfcpp::DW_CFA_nop)
            len -= resolve_size;
          else
            {