gdb: add accessors for field (and call site) location

Add accessors for the various location values in struct field.  This
lets us assert that when we get a location value of a certain kind (say,
bitpos), the field's location indeed contains a value of that kind.

Remove the SET_FIELD_* macros, instead use the new setters directly.
Update the FIELD_* macros used to access field locations to go through
the getters.  They will be removed in a subsequent patch.

There are places where the FIELD_* macros are used on call_site_target
structures, because it contains members of the same name (loc_kind and
loc).  For now, I have replicated the getters/setters in
call_site_target.  But we could perhaps eventually factor them in a
"location" structure that can be used at both places.

Note that the field structure, being zero-initialized, defaults to a
bitpos location with value 0.  While writing this patch, I tried to make
it default to an "unset" location, to catch places where we would miss
setting a field's location.  However, I found that some places relied on
the default being "bitpos 0", so I left it as-is.  This change could
always be done as follow-up work, making these places explicitly set the
"bitpos 0" location.

I found two issues to fix:

 - I got some failures in the gdb.base/infcall-nested-structs-c++.exp
   test.  They were caused by two functions in amd64-tdep.c using
   TYPE_FIELD_BITPOS before checking if the location is of the bitpos
   kind, which they do indirectly through `field_is_static`.  Simply
   move getting the bitpos below the field_is_static call.

 - I got a failure in gdb.xml/tdesc-regs.exp.  It turns out that in
   make_gdb_type_enum, we set enum field values using SET_FIELD_BITPOS,
   and later access them through FIELD_ENUMVAL.  Fix that by using
   set_loc_enumval to set the value.

Change-Id: I53d3734916c46457576ba11dd77df4049d2fc1e8

1 files changed, 3 insertions, 3 deletions

diff --git a/gdb/coffread.c b/gdb/coffread.c
index 30cf81988c5..225e0e28e95 100644
--- a/gdb/coffread.c
+++ b/gdb/coffread.c
@@ -2012,7 +2012,7 @@ coff_read_struct_type (int index, int length, int lastsym,
 						name));
 	  list->field.set_type (decode_type (ms, ms->c_type, &sub_aux,
 					     objfile));
-	  SET_FIELD_BITPOS (list->field, 8 * ms->c_value);
+	  list->field.set_loc_bitpos (8 * ms->c_value);
 	  FIELD_BITSIZE (list->field) = 0;
 	  nfields++;
 	  break;
@@ -2029,7 +2029,7 @@ coff_read_struct_type (int index, int length, int lastsym,
 						name));
 	  list->field.set_type (decode_type (ms, ms->c_type, &sub_aux,
 					     objfile));
-	  SET_FIELD_BITPOS (list->field, ms->c_value);
+	  list->field.set_loc_bitpos (ms->c_value);
 	  FIELD_BITSIZE (list->field) = sub_aux.x_sym.x_misc.x_lnsz.x_size;
 	  nfields++;
 	  break;
@@ -2145,7 +2145,7 @@ coff_read_enum_type (int index, int length, int lastsym,
 
 	  SYMBOL_TYPE (xsym) = type;
 	  type->field (n).set_name (xsym->linkage_name ());
-	  SET_FIELD_ENUMVAL (type->field (n), SYMBOL_VALUE (xsym));
+	  type->field (n).set_loc_enumval (SYMBOL_VALUE (xsym));
 	  if (SYMBOL_VALUE (xsym) < 0)
 	    unsigned_enum = 0;
 	  TYPE_FIELD_BITSIZE (type, n) = 0;