Data structure definitions for a generic GCC target.
Copyright (C) 2001-2024 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3, or (at your option) any
later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>.
In other words, you are welcome to use, share and improve this program.
You are forbidden to forbid anyone else to use, share and improve
what you give them. Help stamp out software-hoarding!
This file contains a data structure that describes a GCC target.
At present it is incomplete, but in future it should grow to
contain most or all target machine and target O/S specific
information.
This structure has its initializer declared in target-def.h in the
form of large macro TARGET_INITIALIZER that expands to many smaller
macros.
The smaller macros each initialize one component of the structure,
and each has a default. Each target should have a file that
includes target.h and target-def.h, and overrides any inappropriate
defaults by undefining the relevant macro and defining a suitable
replacement. That file should then contain the definition of
"targetm" like so:
struct gcc_target targetm = TARGET_INITIALIZER;
Doing things this way allows us to bring together everything that
defines a GCC target. By supplying a default that is appropriate
to most targets, we can easily add new items without needing to
edit dozens of target configuration files. It should also allow us
to gradually reduce the amount of conditional compilation that is
scattered throughout GCC.
When using a GCC build compiler, we could use
__attribute__((transparent_union)) to get cumulative_args_t function
arguments passed like scalars where the ABI would mandate a less
efficient way of argument passing otherwise. However, that would come
at the cost of less type-safe !CHECKING_P compilation.
1.10.0