[PATCH] Fix localplt check for GNU_IFUNC

[Adhemerval Zanella]

While reviewing the strncat optimization for powerpc64 I noted in the
disassembled object that a call to strlen (bl strlen) generates a PLT
call to strlen (since now strlen is an IFUNC for powerpc64). Strangely
it was not being caught by check-localplt testcase.

GNU_IFUNC are shown by readelf in 'Relocation section' value as (symbol)
instead of expected hexadecimal value. This causes the check-localplt
script to igore potential PLT stub begin generated by wrong IFUNC usage.
This patch changes the localplt script to emit such PLT cases.

Checked on PPC64 and X86_64.

--

2014-03-03  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>

        * scripts/localplt.awk: Do not ignore IFUNC relocation while parsing
	relocation sections.

---

diff --git a/scripts/localplt.awk b/scripts/localplt.awk
index 2265b02..5e38073 100644
--- a/scripts/localplt.awk
+++ b/scripts/localplt.awk
@@ -32,9 +32,15 @@ $1 == "Offset" && $2 == "Info" { in_relocs = 1; next }
 NF == 0 { in_relocs = 0 }
 
 in_relocs && relocs_offset == jmprel_offset && NF >= 5 {
-  symval = strtonum("0x" $4);
-  if (symval != 0)
+  # Relocations against GNU_IFUNC symbols are not shown as an hexadecimal
+  # value, but rather as the resolver symbol name between ().
+  if ($4 ~ /\(.*\)/) {
     print whatfile, $5
+  } else {
+    symval = strtonum("0x" $4);
+    if (symval != 0)
+      print whatfile, $5
+  }
 }
 
 in_relocs { next }