[PATCH PR gdb/18071] TLS variables can't be resolved on aarch64-linux-gnu

[Weimin Pan <weimin.pan@oracle.com>]

Running the test case with upstream gdb shows two failures:

(1) Receiving different error messages when printing TLS variable before
    program runs - because the ARM compiler does not emit dwarf attribute
    DW_AT_location for TLS, the result is expected and the baseline may
    need to be changed for aarch64.

(2) Using "info address" command on C++ static TLS object resulted in
    "symbol unresolved" error - below is a snippet from the test case:

class K {
 public:
  static __thread int another_thread_local;
};

__thread int K::another_thread_local;

(gdb) info address K::another_thread_local
Symbol "K::another_thread_local" is unresolved.

This patch contains fix for (2).

Function info_address_command() handles the "info address" command and
calls lookup_minimal_symbol_and_objfile() to find sym's symbol entry in
mininal symbol table if SYMBOL_COMPUTED_OPS (sym) is false. Problem is
that function lookup_minimal_symbol_and_objfile() only looked up an
objfile's minsym ordinary hash table, not its demangled hash table, which
was the reason why the C++ name was not found.

The fix is to call lookup_minimal_symbol(), which already looks up entries
in both minsym's hash tables, to find names when traversing the object file
list in lookup_minimal_symbol_and_objfile().

Tested in both aarch64-linux-gnu and amd64-linux-gnu. No regressions.
---
 gdb/ChangeLog |    5 +++++
 gdb/minsyms.c |   17 +++--------------
 2 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 4b292e0..2f630bc 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2017-11-01  Weimin Pan  <weimin.pan@oracle.com>
+
+	* minsyms.c (lookup_minimal_symbol_and_objfile): Use
+	lookup_minimal_symbol() to find symbol entry.
+
 2017-10-27  Keith Seitz  <keiths@redhat.com>
 
 	* breakpoint.c (print_breakpoint_location): Use the symbol saved
diff --git a/gdb/minsyms.c b/gdb/minsyms.c
index 37edbd8..4edd8b1 100644
--- a/gdb/minsyms.c
+++ b/gdb/minsyms.c
@@ -881,23 +881,12 @@ lookup_minimal_symbol_and_objfile (const char *name)
 {
   struct bound_minimal_symbol result;
   struct objfile *objfile;
-  unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
 
   ALL_OBJFILES (objfile)
     {
-      struct minimal_symbol *msym;
-
-      for (msym = objfile->per_bfd->msymbol_hash[hash];
-	   msym != NULL;
-	   msym = msym->hash_next)
-	{
-	  if (strcmp (MSYMBOL_LINKAGE_NAME (msym), name) == 0)
-	    {
-	      result.minsym = msym;
-	      result.objfile = objfile;
-	      return result;
-	    }
-	}
+      result = lookup_minimal_symbol (name, NULL, objfile);
+      if (result.minsym != NULL)
+        return result;
     }
 
   memset (&result, 0, sizeof (result));
-- 
1.7.1