This is not really a new entity type but merely a relocation type.
Handle it with a x86_immediate_kind.

This way we don't need a separate frame_entity field in the attribute
struct anymore. We can also use the immediate type to determine whether
we need to assign a fresh stackentity to a node.
This commit does not change the frame_use field, which is now a
duplicate way to indicate whether we need to assign a stackentity. This
currently requires a lot of asserts to ensure the two stay in sync. In
the future I'd like to use frame_use only for the special case when a
32bit or 64bit entity needs to be forced.

The flag has been superseded by the immediate kind.

It is now required to set a (relocation) kind when entity != NULL.
Adds IMM_ADDR, PICBASE_REL kinds to differentiate between absolute
addresses and picbase relative addresses. Maintain the no_picbase_adjust
flag in parallel for testing. We should be able to remove it in a
subsequent commit.

be: Factorise the code to emit an asm node and use a callback for each backend to output the operands.

The common_transform stuff was meant to be reused by the PBQP code
selection which is not maintained anymore.

It returns a null pointer instead of a ia32_NoReg_GP.

This avoids the custom emitter, which just duplicated what the generic machinery does.

Some callers did not handle it.
They cannot be permuted (e.g. Jcc).

ia32: Use arch_get_irn_register() instead of arch_get_irn_register_in() where the operand is already available.

The noreg is always different to any output register.

This properly models the data dependencies and avoids keep edges.

ia32: Merge the attributes use_frame, need_stackent, need_32bit_stackent and need_64bit_stackent into one attribute.

* Out of the 16 possible combinations of these four boolean attributes, only four are sensible.
* This correct the latent bug, that not all of these attributes were compared in ia32_attrs_equal_().