This was causing zig2.exe to crash during bootstrap, because there was an atomic
load of read-only memory, and the attempt to write to it as part of the (idempotent)
atomic exchange was invalid.
Aligned reads (of u32 / u64) are atomic on x86 / x64, so this is replaced with an
optimization-proof load (`__iso_volatile_load8*`) and a reordering barrier.
This reverts commit a7de02e052.
This did not implement the accepted proposal, and I did not sign off
on the changes. I would like a chance to review this, please.
This reverts commit 7161ed79c4, reversing
changes made to 3f2a65594e.
Unfortunately, this sat in the PR queue too long and the merge broke the
zig1.wasm bootstrap process.
Changes:
- Add `isMangledIdent` to determine if `fmtIdent` would make any edits to the identifier
- Any function that has a mangled identifier is referred to using the mangled identifer
within the current file, but if it is exported the first export will be with the non-mangled name.
- Add `zig_import` to import a symbol under a different name
- Add a level of indirection to float function names. Now, they are referred to as
`zig_float_fn_<float type>_<operation>`. The definitions in zig.h are wrapped
with `zig_import` to import the symbol under the real name.
The specific problem that sparked this change was the combination of
`zig_libc_name_f80(name) __##name##x` with the input `fma`, resulting
in `__fmax`, which is a new intrinsic in recent versions of cl.exe.
With the above changes in place, compiler_rt can output the following:
```
static zig_weak_linkage_fn zig_f80 zig_e___fmax(zig_f80, zig_f80, zig_f80);
zig_export(zig_weak_linkage_fn zig_f80 zig_e___fmax(zig_f80, zig_f80, zig_f80), __fmax, "__fmax");
```
Within compiler_rt, `zig_e___fmax` is used to refer to the function, but consumers
will import `__fmax`, which maps to their `zig_float_fn_f80_fma` definition from zig.h.
* `CMakeLists.txt`: support the weird `uname -m` output.
* `CMakeLists.txt`: detect and use the C compiler's default arm mode.
* cbe: support gcc with both `f128` and `u128` emulated.
* std.os.linux.thumb: fix incorrectly passed asm inputs.
* Disable 128-bit atomics for x86_64 generic (currently also baseline)
because they require heavy abi agreement to correctly lower.
** This is a breaking change **
* Enable 128-bit atomics for aarch64 in Sema since it just works.
Fixes the abi of `f128` on darwin and/or aarch64. Also, when `double`
and `long double` were the same size, we used to incorrectly define
`zig_c_longdouble` as `zig_f128`.
Since the Zig language documentation claims support for `.Min` and
`.Max` in `@atomicRmw` with floats, allow in Sema and implement for both
the llvm and C backends.
This introduces a new builtin function that compiles down to something that results in an illegal instruction exception/interrupt.
It can be used to exit a program abnormally.
This implements the builtin for all backends.
