[ARM][objdump][2.24] Backport "Skip private symbol when doing objdump"

[Jiong Wang <jiong dot wang at arm dot com>]

this is a backport of

  https://sourceware.org/ml/binutils/2015-02/msg00012.html to 2.24

the patch could be cleanly applied to the branch, and passed cross 
binutils check.

ok for branch?

Thanks.

2015-03-11  Jiong Wang  <jiong.wang@arm.com>

opcodes/
  * arm-dis.c (arm_symbol_is_valid): Skip ARM private symbols.

binutils/testsuite/
  * binutils-all/arm/rvct_symbol.s: New testcase.
  * binutils-all/arm/objdump.exp: Run it.

diff --git a/binutils/testsuite/binutils-all/arm/objdump.exp b/binutils/testsuite/binutils-all/arm/objdump.exp
index ce5a42c..cd10c4b 100644
--- a/binutils/testsuite/binutils-all/arm/objdump.exp
+++ b/binutils/testsuite/binutils-all/arm/objdump.exp
@@ -86,3 +86,25 @@ if [regexp $want $got] then {
 } else {
     fail "multiple input files"
 }
+
+if {![binutils_assemble $srcdir/$subdir/rvct_symbol.s tmpdir/rvct_symbol.o]} then {
+    return
+}
+
+if [is_remote host] {
+    set objfile [remote_download host tmpdir/rvct_symbol.o]
+} else {
+    set objfile tmpdir/rvct_symbol.o
+}
+
+# Make sure multiple disassemblies come out the same
+
+set got [binutils_run $OBJDUMP "-D $objfile $objfile"]
+
+set want "foo.*global_a.*global_b"
+
+if [regexp $want $got] then {
+    pass "skip rvct symbol"
+} else {
+    fail "skip rvct symbol"
+}
diff --git a/binutils/testsuite/binutils-all/arm/rvct_symbol.s b/binutils/testsuite/binutils-all/arm/rvct_symbol.s
new file mode 100644
index 0000000..f63240b
--- /dev/null
+++ b/binutils/testsuite/binutils-all/arm/rvct_symbol.s
@@ -0,0 +1,15 @@
+	.text
+foo:
+__tagsym$$0:
+  add r0, r1, r2
+
+	.data
+	.global	global_a
+__tagsym$$used0:
+global_a:
+	.word 0xcafedead
+
+	.global	__tagsym$$used1
+__tagsym$$used1:
+global_b:
+	.word 0xcafecafe
diff --git a/opcodes/arm-dis.c b/opcodes/arm-dis.c
index e0a82c0..994586d 100644
--- a/opcodes/arm-dis.c
+++ b/opcodes/arm-dis.c
@@ -4558,7 +4558,10 @@ print_insn_data (bfd_vma pc ATTRIBUTE_UNUSED,
 }
 
 /* Disallow mapping symbols ($a, $b, $d, $t etc) from
-   being displayed in symbol relative addresses.  */
+   being displayed in symbol relative addresses.
+
+   Also disallow private symbol, with __tagsym$$ prefix,
+   from ARM RVCT toolchain being displayed.  */
 
 bfd_boolean
 arm_symbol_is_valid (asymbol * sym,
@@ -4571,7 +4574,7 @@ arm_symbol_is_valid (asymbol * sym,
 
   name = bfd_asymbol_name (sym);
 
-  return (name && *name != '$');
+  return (name && *name != '$' && strncmp (name, "__tagsym$$", 10));
 }
 
 /* Parse an individual disassembler option.  */