PR gdb/21226: Take DWARF stack value pieces from LSB end

[deliverable/binutils-gdb.git] / gdb / dwarf2loc.c

diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 2a45a79b50967c99351b96b96fb74f1ebd5f471f..061ec6dbdfb7ad525edbb58c1dbb1664a47741b8 100644 (file)
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -1858,6 +1858,10 @@ read_pieced_value (struct value *v)
                if (unavail)
                  mark_value_bits_unavailable (v, offset, this_size_bits);
              }
+
+           copy_bitwise (contents, dest_offset_bits,
+                         intermediate_buffer, source_offset_bits % 8,
+                         this_size_bits, bits_big_endian);
          }
          break;
 
@@ -1866,26 +1870,30 @@ read_pieced_value (struct value *v)
                             p->v.mem.in_stack_memory,
                             p->v.mem.addr + source_offset,
                             buffer.data (), this_size);
+         copy_bitwise (contents, dest_offset_bits,
+                       intermediate_buffer, source_offset_bits % 8,
+                       this_size_bits, bits_big_endian);
          break;
 
        case DWARF_VALUE_STACK:
          {
-           size_t n = this_size;
+           struct objfile *objfile = dwarf2_per_cu_objfile (c->per_cu);
+           struct gdbarch *objfile_gdbarch = get_objfile_arch (objfile);
+           ULONGEST stack_value_size_bits
+             = 8 * TYPE_LENGTH (value_type (p->v.value));
 
-           if (n > c->addr_size - source_offset)
-             n = (c->addr_size >= source_offset
-                  ? c->addr_size - source_offset
-                  : 0);
-           if (n == 0)
-             {
-               /* Nothing.  */
-             }
-           else
-             {
-               const gdb_byte *val_bytes = value_contents_all (p->v.value);
+           /* Use zeroes if piece reaches beyond stack value.  */
+           if (p->size > stack_value_size_bits)
+             break;
 
-               intermediate_buffer = val_bytes + source_offset;
-             }
+           /* Piece is anchored at least significant bit end.  */
+           if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
+             source_offset_bits += stack_value_size_bits - p->size;
+
+           copy_bitwise (contents, dest_offset_bits,
+                         value_contents_all (p->v.value),
+                         source_offset_bits,
+                         this_size_bits, bits_big_endian);
          }
          break;
 
@@ -1899,6 +1907,10 @@ read_pieced_value (struct value *v)
                   : 0);
            if (n != 0)
              intermediate_buffer = p->v.literal.data + source_offset;
+
+           copy_bitwise (contents, dest_offset_bits,
+                         intermediate_buffer, source_offset_bits % 8,
+                         this_size_bits, bits_big_endian);
          }
          break;
 
@@ -1915,12 +1927,6 @@ read_pieced_value (struct value *v)
          internal_error (__FILE__, __LINE__, _("invalid location type"));
        }
 
-      if (p->location != DWARF_VALUE_OPTIMIZED_OUT
-         && p->location != DWARF_VALUE_IMPLICIT_POINTER)
-       copy_bitwise (contents, dest_offset_bits,
-                     intermediate_buffer, source_offset_bits % 8,
-                     this_size_bits, bits_big_endian);
-
       offset += this_size_bits;
     }
 }