Add initial type alignment support

This adds some basic type alignment support to gdb.  It changes struct
type to store the alignment, and updates dwarf2read.c to handle
DW_AT_alignment.  It also adds a new gdbarch method and updates
i386-tdep.c.

None of this new functionality is used anywhere yet, so tests will
wait until the next patch.

2018-04-30  Tom Tromey  <tom@tromey.com>

	* i386-tdep.c (i386_type_align): New function.
	(i386_gdbarch_init): Update.
	* gdbarch.sh (type_align): New method.
	* gdbarch.c, gdbarch.h: Rebuild.
	* arch-utils.h (default_type_align): Declare.
	* arch-utils.c (default_type_align): New function.
	* gdbtypes.h (TYPE_ALIGN_BITS): New define.
	(struct type) <align_log2>: New field.
	<instance_flags>: Now a bitfield.
	(TYPE_RAW_ALIGN): New macro.
	(type_align, type_raw_align, set_type_align): Declare.
	* gdbtypes.c (type_align, type_raw_align, set_type_align): New
	functions.
	* dwarf2read.c (quirk_rust_enum): Set type alignment.
	(get_alignment, maybe_set_alignment): New functions.
	(read_structure_type, read_enumeration_type, read_array_type)
	(read_set_type, read_tag_pointer_type, read_tag_reference_type)
	(read_subrange_type, read_base_type): Set type alignment.

1 files changed, 23 insertions, 0 deletions

diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index 1359c2f..dd7c89d 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -353,6 +353,7 @@ struct gdbarch
   gdbarch_addressable_memory_unit_size_ftype *addressable_memory_unit_size;
   char ** disassembler_options;
   const disasm_options_t * valid_disassembler_options;
+  gdbarch_type_align_ftype *type_align;
 };
 
 /* Create a new ``struct gdbarch'' based on information provided by
@@ -465,6 +466,7 @@ gdbarch_alloc (const struct gdbarch_info *info,
   gdbarch->gcc_target_options = default_gcc_target_options;
   gdbarch->gnu_triplet_regexp = default_gnu_triplet_regexp;
   gdbarch->addressable_memory_unit_size = default_addressable_memory_unit_size;
+  gdbarch->type_align = default_type_align;
   /* gdbarch_alloc() */
 
   return gdbarch;
@@ -716,6 +718,7 @@ verify_gdbarch (struct gdbarch *gdbarch)
   /* Skip verify of addressable_memory_unit_size, invalid_p == 0 */
   /* Skip verify of disassembler_options, invalid_p == 0 */
   /* Skip verify of valid_disassembler_options, invalid_p == 0 */
+  /* Skip verify of type_align, invalid_p == 0 */
   if (!log.empty ())
     internal_error (__FILE__, __LINE__,
                     _("verify_gdbarch: the following are invalid ...%s"),
@@ -1442,6 +1445,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
                       "gdbarch_dump: target_desc = %s\n",
                       host_address_to_string (gdbarch->target_desc));
   fprintf_unfiltered (file,
+                      "gdbarch_dump: type_align = <%s>\n",
+                      host_address_to_string (gdbarch->type_align));
+  fprintf_unfiltered (file,
                       "gdbarch_dump: gdbarch_unwind_pc_p() = %d\n",
                       gdbarch_unwind_pc_p (gdbarch));
   fprintf_unfiltered (file,
@@ -5100,6 +5106,23 @@ set_gdbarch_valid_disassembler_options (struct gdbarch *gdbarch,
   gdbarch->valid_disassembler_options = valid_disassembler_options;
 }
 
+ULONGEST
+gdbarch_type_align (struct gdbarch *gdbarch, struct type *type)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->type_align != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_type_align called\n");
+  return gdbarch->type_align (gdbarch, type);
+}
+
+void
+set_gdbarch_type_align (struct gdbarch *gdbarch,
+                        gdbarch_type_align_ftype type_align)
+{
+  gdbarch->type_align = type_align;
+}
+
 
 /* Keep a registry of per-architecture data-pointers required by GDB
    modules.  */