gdb: add type parameter to value::allocate_register and add value::allocate_register_lazy

Some places that create register struct values don't use register_type
to obtain the value type.  This prevents them from using the current
version of value::allocate_register.  One spot (value_of_register_lazy)
also creates a lazy register value.

Add a value::allocate_register_lazy method.  Add some type parameters
to value::allocate_register and value::allocate_register_lazy, to let
the caller specify the type to use for the value.  The parameters
default to nullptr, in which case we use register_type to obtain the
type.

Change-Id: I640ec0a5a0f4a55eba12d515dbfd25933229f8ec

4 files changed, 37 insertions, 35 deletions

diff --git a/gdb/findvar.c b/gdb/findvar.c
index f184b63fc85..f48033d1bd3 100644
--- a/gdb/findvar.c
+++ b/gdb/findvar.c
@@ -281,12 +281,7 @@ value_of_register_lazy (frame_info_ptr next_frame, int regnum)
   /* We should have a valid next frame.  */
   gdb_assert (frame_id_p (get_frame_id (next_frame)));
 
-  value *reg_val = value::allocate_lazy (register_type (gdbarch, regnum));
-  reg_val->set_lval (lval_register);
-  VALUE_REGNUM (reg_val) = regnum;
-  VALUE_NEXT_FRAME_ID (reg_val) = get_frame_id (next_frame);
-
-  return reg_val;
+  return value::allocate_register_lazy (next_frame, regnum);
 }
 
 /* Given a pointer of type TYPE in target form in BUF, return the
@@ -751,25 +746,20 @@ value *
 default_value_from_register (gdbarch *gdbarch, type *type, int regnum,
 			     const frame_info_ptr &this_frame)
 {
-  int len = type->length ();
-  struct value *value = value::allocate (type);
-  value->set_lval (lval_register);
-
   frame_info_ptr next_frame = get_next_frame_sentinel_okay (this_frame);
   while (get_frame_type (next_frame) == INLINE_FRAME)
     next_frame = get_next_frame_sentinel_okay (next_frame);
 
-  VALUE_NEXT_FRAME_ID (value) = get_frame_id (next_frame);
-  VALUE_REGNUM (value) = regnum;
+  value *value = value::allocate_register (next_frame, regnum, type);
 
   /* Any structure stored in more than one register will always be
      an integral number of registers.  Otherwise, you need to do
      some fiddling with the last register copied here for little
      endian machines.  */
   if (type_byte_order (type) == BFD_ENDIAN_BIG
-      && len < register_size (gdbarch, regnum))
+      && type->length () < register_size (gdbarch, regnum))
     /* Big-endian, and we want less than full size.  */
-    value->set_offset (register_size (gdbarch, regnum) - len);
+    value->set_offset (register_size (gdbarch, regnum) - type->length ());
   else
     value->set_offset (0);
 
@@ -842,10 +832,8 @@ value_from_register (struct type *type, int regnum, frame_info_ptr frame)
 	 the corresponding [integer] type (see Alpha).  The assumption
 	 is that gdbarch_register_to_value populates the entire value
 	 including the location.  */
-      v = value::allocate (type);
-      v->set_lval (lval_register);
-      VALUE_NEXT_FRAME_ID (v) = get_frame_id (get_next_frame_sentinel_okay (frame));
-      VALUE_REGNUM (v) = regnum;
+      v = value::allocate_register (get_next_frame_sentinel_okay (frame),
+				    regnum, type);
       ok = gdbarch_register_to_value (gdbarch, frame, regnum, type1,
 				      v->contents_raw ().data (), &optim,
 				      &unavail);
diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c
index 6dae744dab9..53c4fd72634 100644
--- a/gdb/rs6000-tdep.c
+++ b/gdb/rs6000-tdep.c
@@ -2751,30 +2751,25 @@ static value *
 rs6000_value_from_register (gdbarch *gdbarch, type *type, int regnum,
 			    const frame_info_ptr &this_frame)
 {
-  int len = type->length ();
-  struct value *value = value::allocate (type);
-
   /* We have an IEEE 128-bit float -- need to change regnum mapping from
      fpr to vsr.  */
   regnum = ieee_128_float_regnum_adjust (gdbarch, type, regnum);
 
-  value->set_lval (lval_register);
-
   frame_info_ptr next_frame = get_next_frame_sentinel_okay (this_frame);
   while (get_frame_type (next_frame) == INLINE_FRAME)
     next_frame = get_next_frame_sentinel_okay (next_frame);
 
-  VALUE_NEXT_FRAME_ID (value) = get_frame_id (next_frame);
-  VALUE_REGNUM (value) = regnum;
+  value *value
+    = value::allocate_register (next_frame, regnum, type);
 
   /* Any structure stored in more than one register will always be
      an integral number of registers.  Otherwise, you need to do
      some fiddling with the last register copied here for little
      endian machines.  */
   if (type_byte_order (type) == BFD_ENDIAN_BIG
-      && len < register_size (gdbarch, regnum))
+      && type->length () < register_size (gdbarch, regnum))
     /* Big-endian, and we want less than full size.  */
-    value->set_offset (register_size (gdbarch, regnum) - len);
+    value->set_offset (register_size (gdbarch, regnum) - type->length ());
   else
     value->set_offset (0);
 
diff --git a/gdb/value.c b/gdb/value.c
index 7523af14234..7d51396a0e3 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -961,11 +961,14 @@ value::allocate (struct type *type)
 
 /* See value.h  */
 
-struct value *
-value::allocate_register (frame_info_ptr next_frame, int regnum)
+value *
+value::allocate_register_lazy (frame_info_ptr next_frame, int regnum,
+			       struct type *type)
 {
-  value *result
-    = value::allocate (register_type (frame_unwind_arch (next_frame), regnum));
+  if (type == nullptr)
+    type = register_type (frame_unwind_arch (next_frame), regnum);
+
+  value *result = value::allocate_lazy (type);
 
   result->set_lval (lval_register);
   VALUE_REGNUM (result) = regnum;
@@ -974,6 +977,17 @@ value::allocate_register (frame_info_ptr next_frame, int regnum)
   return result;
 }
 
+/* See value.h  */
+
+value *
+value::allocate_register (frame_info_ptr next_frame, int regnum,
+			  struct type *type)
+{
+  value *result = value::allocate_register_lazy (next_frame, regnum, type);
+  result->set_lazy (false);
+  return result;
+}
+
 /* Allocate a  value  that has the correct length
    for COUNT repetitions of type TYPE.  */
 
diff --git a/gdb/value.h b/gdb/value.h
index c114f46bc50..86ad3ff959f 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -159,12 +159,17 @@ public:
   /* Allocate a value and its contents for type TYPE.  */
   static struct value *allocate (struct type *type);
 
-  /* Allocate a non-lazy value representing register RENUM in the frame previous
-     to NEXT_FRAME.  The type of the value is found using `register_type`.
-
+  /* Allocate a lazy value representing register REGNUM in the frame previous
+     to NEXT_FRAME.  If TYPE is non-nullptr, use it as the value type.
+     Otherwise, use `register_type` to obtain the type.  */
+  static struct value *allocate_register_lazy (frame_info_ptr next_frame,
+					  int regnum, type *type = nullptr);
+
+  /* Same as `allocate_register_lazy`, but make the value non-lazy.
+  
      The caller is responsible for filling the value's contents.  */
   static struct value *allocate_register (frame_info_ptr next_frame,
-					  int regnum);
+					  int regnum, type *type = nullptr);
 
   /* Create a computed lvalue, with type TYPE, function pointers
      FUNCS, and closure CLOSURE.  */