diff mbox

Clear upper bits during sign extension

Message ID 87bnm9u8wx.fsf@codesourcery.com
State New
Headers show

Commit Message

Yao Qi Jan. 8, 2015, 5:40 a.m. UTC
Yao Qi <yao@codesourcery.com> writes:

>> +  byte_order = gdbarch_byte_order (get_type_arch (type));
>
> How about getting gdbarch via get_frame_arch (frame)?  How about
> removing gdb_sign_extend as it is no longer used?
>
> I'll post a full version on top of yours.

Here is the patch, what do you think?

Comments

Pedro Alves Jan. 8, 2015, 10:41 a.m. UTC | #1
On 01/08/2015 05:40 AM, Yao Qi wrote:
> Yao Qi <yao@codesourcery.com> writes:
> 
>>> +  byte_order = gdbarch_byte_order (get_type_arch (type));
>>
>> How about getting gdbarch via get_frame_arch (frame)?  How about
>> removing gdb_sign_extend as it is no longer used?
>>
>> I'll post a full version on top of yours.
> 
> Here is the patch, what do you think?

Looks good to me.  Thanks.
Yao Qi Jan. 8, 2015, 1:06 p.m. UTC | #2
Pedro Alves <palves@redhat.com> writes:

> Looks good to me.  Thanks.

Patch is pushed in.
diff mbox

Patch

diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 2bd12d6..bdb2160 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -2012,6 +2012,7 @@  indirect_pieced_value (struct value *value)
   int i, bit_offset, bit_length;
   struct dwarf_expr_piece *piece = NULL;
   LONGEST byte_offset;
+  enum bfd_endian byte_order;
 
   type = check_typedef (value_type (value));
   if (TYPE_CODE (type) != TYPE_CODE_PTR)
@@ -2056,11 +2057,16 @@  indirect_pieced_value (struct value *value)
   /* This is an offset requested by GDB, such as value subscripts.
      However, due to how synthetic pointers are implemented, this is
      always presented to us as a pointer type.  This means we have to
-     sign-extend it manually as appropriate.  */
-  byte_offset = value_as_address (value);
-  if (TYPE_LENGTH (value_type (value)) < sizeof (LONGEST))
-    byte_offset = gdb_sign_extend (byte_offset,
-				   8 * TYPE_LENGTH (value_type (value)));
+     sign-extend it manually as appropriate.  Use raw
+     extract_signed_integer directly rather than value_as_address and
+     sign extend afterwards on architectures that would need it
+     (mostly everywhere except MIPS, which has signed addresses) as
+     the later would go through gdbarch_pointer_to_address and thus
+     return a CORE_ADDR with high bits set on architectures that
+     encode address spaces and other things in CORE_ADDR.  */
+  byte_order = gdbarch_byte_order (get_frame_arch (frame));
+  byte_offset = extract_signed_integer (value_contents (value),
+					TYPE_LENGTH (type), byte_order);
   byte_offset += piece->v.ptr.offset;
 
   gdb_assert (piece);
diff --git a/gdb/utils.c b/gdb/utils.c
index 084db87..72b1e2a 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -3021,23 +3021,6 @@  align_down (ULONGEST v, int n)
   return (v & -n);
 }
 
-/* See utils.h.  */
-
-LONGEST
-gdb_sign_extend (LONGEST value, int bit)
-{
-  gdb_assert (bit >= 1 && bit <= 8 * sizeof (LONGEST));
-
-  if (((value >> (bit - 1)) & 1) != 0)
-    {
-      LONGEST signbit = ((LONGEST) 1) << (bit - 1);
-
-      value = (value ^ signbit) - signbit;
-    }
-
-  return value;
-}
-
 /* Allocation function for the libiberty hash table which uses an
    obstack.  The obstack is passed as DATA.  */
 
diff --git a/gdb/utils.h b/gdb/utils.h
index 0a73864..3debde7 100644
--- a/gdb/utils.h
+++ b/gdb/utils.h
@@ -340,11 +340,6 @@  extern int myread (int, char *, int);
 extern ULONGEST align_up (ULONGEST v, int n);
 extern ULONGEST align_down (ULONGEST v, int n);
 
-/* Sign extend VALUE.  BIT is the (1-based) index of the bit in VALUE
-   to sign-extend.  */
-
-extern LONGEST gdb_sign_extend (LONGEST value, int bit);
-
 /* Resource limits used by getrlimit and setrlimit.  */
 
 enum resource_limit_kind