This partially reverts https://github.com/ruby/ruby/pull/10944; now that
we decided to pass CFLAGS to $(CC) when assembling .S files, we don't
need these autoconf macros that capture the state of
__ARM_FEATURE{PAC|BTI}_DEFAULT.
[Bug #20601]
This changes the automatic detection of -fstack-protector,
-D_FORTIFY_SOURCE, and -mbranch-protection to write to $hardenflags
instead of $XCFLAGS. The definition of $cflags is changed to
"$hardenflags $orig_cflags $optflags $debugflags $warnflags" to match.
Furthermore, these flags are _prepended_ to $hardenflags, rather than
appended.
The implications of doing this are as follows:
* If a CRuby builder specifies cflags="-mbranch-protection=foobar" at
the ./configure script, and the configure script detects that
-mbranch-protection=pac-ret is accepted, then GCC will be invoked as
"gcc -mbranch-protection=pac-ret -mbranch-protection=foobar". Since
the last flags take precedence, that means that user-supplied values
of these flags in $cflags will take priority.
* Likewise, if a CRuby builder explicitly specifies
"hardenflags=-mbranch-protection=foobar", because we _prepend_ to
$hardenflags in our autoconf script, we will still invoke GCC as
"gcc -mbranch-protection=pac-ret -mbranch-protection=foobar".
* If a CRuby builder specifies CFLAGS="..." at the configure line,
automatic detection of hardening flags is ignored as before.
* C extensions will _also_ be built with hardening flags now as well
(this was not the case by default before because the detected flags
went into $XCFLAGS).
Additionally, as part of this work, I changed how the detection of
PAC/BTI in Context.S works. Rather than appending the autodetected
option to ASFLAGS, we simply compile a set of test programs with the
actual CFLAGS in use to determine what PAC/BTI settings were actually
chosen by the builder. Context.S is made aware of these choices through
some custom macros.
The result of this work is that:
* Ruby will continue to choose some sensible defaults for hardening
options for the C compiler
* Distributors are able to specify CFLAGS that are consistent with their
distribution and override these defaults
* Context.S will react to whatever -mbranch-protection is actually in
use, not what was autodetected
* Extensions get built with hardening flags too.
[Bug #20154]
[Bug #20520]
With `--std=c99` option coroutine/arm64/Context.h errs:
```
In file included from cont.c:26:
coroutine/arm64/Context.h:59:5: error: call to undeclared function 'asm'; ISO C99 and later do not support
implicit function declarations [-Wimplicit-function-declaration]
59 | asm ("hint #8;" : "+r"(r17) : "r"(r16));
| ^
```
Also move the common function header.
We don't need to save/restore x30 twice, and we can just use `ret`,
which uses x30 as return address register instead of explicit `ret <reg>`
instruction. This also allows us to use `autiasp` instead of `autia1716`
and we can skip setting SP/LR to x16/x17.
Also the size of register save area is shrunk by 16 bytes due to the
removal of extra x30 save/restore.
Saves comitters' daily life by avoid #include-ing everything from
internal.h to make each file do so instead. This would significantly
speed up incremental builds.
We take the following inclusion order in this changeset:
1. "ruby/config.h", where _GNU_SOURCE is defined (must be the very
first thing among everything).
2. RUBY_EXTCONF_H if any.
3. Standard C headers, sorted alphabetically.
4. Other system headers, maybe guarded by #ifdef
5. Everything else, sorted alphabetically.
Exceptions are those win32-related headers, which tend not be self-
containing (headers have inclusion order dependencies).
It is more conventional to use compiler to pre-process and
assemble the `.S` file rather than forcing Makefile to use `.s`.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65952 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
