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Fix "overflow in PLT unwind data" warning
- From: Alan Modra <amodra at gmail dot com>
- To: binutils at sourceware dot org
- Cc: Cary Coutant <ccoutant at google dot com>, Brooks Moses <bmoses at google dot com>
- Date: Thu, 15 May 2014 18:49:27 +0930
- Subject: Fix "overflow in PLT unwind data" warning
- Authentication-results: sourceware.org; auth=none
When linking statically, it's possible to hit this gold 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/powerpc.cc b/gold/powerpc.cc
index b9ee86e..e59c319 100644
--- 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
{
--
Alan Modra
Australia Development Lab, IBM