With 638 macros documented by @defmac, and 475 files that include tm.h , our current approach to hookization is too slow to get the tree optimizers and front ends independent of target macros in any useful timeframe.
Therefore, I propose the following approach: The target macros currently required by tree optimizers and frontends get wrapper hooks, and these wrapper hooks get wrapper macros, to look like the original target macros, defined in the auto-generated header-file target-wrap.h . cc1/cc1plus etc. source files that currently include "tm.h", but have no business to do so, will be changed to include target-wrap.h instead; if they include "tm_p.h", this include will also be removed. The @defmac definitions from tm.texi.in give a tentative list of macros, although that is probably incomplete, while some macros are already wrapped or not needed outside of rtl-centric code. So I'll convert or generate (in the undocumented case) hook wrapper definitions for the functional macros definitions that are evidently needed to perform a bootstrap and various cross-builds. In particular, I'll have to fill in argument and return types for each required hook. I use @wrapper for a syntax similar to @hook, except that no default definition is specified; instead, it is auto-generated, with a new auto-generated file target-wrappers.c to implement the hook wrappers. I'll create all the wrapper hooks initially as sub-members of a new targetm.wrapper member; If people would like them somewhere else, we can move them around later, but discussing individual placement of some sixhundred hooks beforehand would just slow down things too much.
