We have name fragmentation for this feature, including "shared GC",
"modular GC", and "external GC". This commit standardizes the feature
name to "modular GC" and the implementation to "GC library".
This commit changes the external GC API to use `--with-shared-gc=DIR` at
configure time with a directory of the external GC and uses
`RUBY_GC_LIBRARY` environment variable to load the external GC at
runtime.
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]
Make the WASI_SDK_PATH variable mandatory when building for wasi host.
This requirement prevents developers from being stuck due to unfriendly
configuration's error message.
configure.ac: setup build tools and register objects
main.c: wrap main with rb_wasm_rt_start to handle asyncify unwinds
tool/m4/ruby_wasm_tools.m4: setup default command based on WASI_SDK_PATH
environment variable. checks wasm-opt which is used for asyncify.
tool/wasm-clangw wasm/wasm-opt: a clang wrapper which replaces real
wasm-opt with do-nothing wasm-opt to avoid misoptimization before
asyncify. asyncify is performed at POSTLINK, but clang linker driver
tries to run optimization by wasm-opt unconditionally. inlining pass
at wasm level breaks asyncify's assumption, so should not optimize
before POSTLIK.
wasm/GNUmakefile.in: wasm specific rules to compile objects
Before 9189cf5793 the result of
`m4_version_compare` was compared to -1, however the `$2` of
`m4_version_prereq` has different meaning and is expanded when
the required version met.
Namely recent Sun C compiler has this function, and is not a GCC.
Meanwhile the code without RUBY_JMP_BUF assumes GCC. We have to define
the macro when we detect __builtin_setjmp for non-GCC compilers.
The built-in version operates on a buffer of 5 words, much smaller than
the size of jmp_buf defined in libc.
Note, powerpc requires 5 words, while arm and x86_64 just require 3.
