baab4fd89c
Adds generic conversion from a wider to a narrower IEEE-754 floating-point type. Implement `__truncdfsf2` and `__truncdfsf2vfp` and associated test-cases.
402 lines
11 KiB
Markdown
402 lines
11 KiB
Markdown
# `compiler-builtins`
|
|
|
|
[](https://ci.appveyor.com/project/rust-lang-libs/compiler-builtins)
|
|
[](https://travis-ci.org/rust-lang-nursery/compiler-builtins)
|
|
|
|
> [WIP] Porting `compiler-rt` intrinsics to Rust
|
|
|
|
See [rust-lang/rust#35437][0].
|
|
|
|
[0]: https://github.com/rust-lang/rust/issues/35437
|
|
|
|
## When and how to use this crate?
|
|
|
|
If you are working with a target that doesn't have binary releases of std
|
|
available via rustup (this probably means you are building the core crate
|
|
yourself) and need compiler-rt intrinsics (i.e. you are probably getting linker
|
|
errors when building an executable: `undefined reference to __aeabi_memcpy`),
|
|
you can use this crate to get those intrinsics and solve the linker errors. To
|
|
do that, add this crate somewhere in the dependency graph of the crate you are
|
|
building:
|
|
|
|
``` toml
|
|
# Cargo.toml
|
|
[dependencies]
|
|
compiler_builtins = { git = "https://github.com/rust-lang-nursery/compiler-builtins" }
|
|
```
|
|
|
|
``` rust
|
|
extern crate compiler_builtins;
|
|
|
|
// ...
|
|
```
|
|
|
|
If you still get an "undefined reference to $INTRINSIC" error after that change,
|
|
that means that we haven't ported `$INTRINSIC` to Rust yet! Please open [an
|
|
issue] with the name of the intrinsic and the LLVM triple (e.g.
|
|
thumbv7m-none-eabi) of the target you are using. That way we can prioritize
|
|
porting that particular intrinsic.
|
|
|
|
If you've got a C compiler available for your target then while we implement
|
|
this intrinsic you can temporarily enable a fallback to the actual compiler-rt
|
|
implementation as well for unimplemented intrinsics:
|
|
|
|
```toml
|
|
[dependencies.compiler_builtins]
|
|
git = "https://github.com/rust-lang-nursery/compiler-builtins"
|
|
features = ["c"]
|
|
```
|
|
|
|
[an issue]: https://github.com/rust-lang-nursery/compiler-builtins/issues
|
|
|
|
## Contributing
|
|
|
|
1. Pick one or more intrinsics from the [pending list](#progress).
|
|
2. Fork this repository.
|
|
3. Port the intrinsic(s) and their corresponding [unit tests][1] from their
|
|
[C implementation][2] to Rust.
|
|
4. Implement a [test generator][3] to compare the behavior of the ported intrinsic(s)
|
|
with their implementation on the testing host. Note that randomized compiler-builtin tests
|
|
should be run using `cargo test --features gen-tests`.
|
|
4. Send a Pull Request (PR).
|
|
5. Once the PR passes our extensive [testing infrastructure][4], we'll merge it!
|
|
6. Celebrate :tada:
|
|
|
|
[1]: https://github.com/rust-lang/compiler-rt/tree/8598065bd965d9713bfafb6c1e766d63a7b17b89/test/builtins/Unit
|
|
[2]: https://github.com/rust-lang/compiler-rt/tree/8598065bd965d9713bfafb6c1e766d63a7b17b89/lib/builtins
|
|
[3]: https://github.com/rust-lang-nursery/compiler-builtins/blob/0ba07e49264a54cb5bbd4856fcea083bb3fbec15/build.rs#L180-L265
|
|
[4]: https://travis-ci.org/rust-lang-nursery/compiler-builtins
|
|
|
|
### Porting Reminders
|
|
|
|
1. [Rust][5a] and [C][5b] have slightly different operator precedence. C evaluates comparisons (`== !=`) before bitwise operations (`& | ^`), while Rust evaluates the other way.
|
|
2. C assumes wrapping operations everywhere. Rust panics on overflow when in debug mode. Consider using the [Wrapping][6] type or the explicit [wrapping_*][7] functions where applicable.
|
|
3. Note [C implicit casts][8], especially integer promotion. Rust is much more explicit about casting, so be sure that any cast which affects the output is ported to the Rust implementation.
|
|
4. Rust has [many functions][9] for integer or floating point manipulation in the standard library. Consider using one of these functions rather than porting a new one.
|
|
|
|
[5a]: https://doc.rust-lang.org/reference/expressions.html#expression-precedence
|
|
[5b]: http://en.cppreference.com/w/c/language/operator_precedence
|
|
[6]: https://doc.rust-lang.org/core/num/struct.Wrapping.html
|
|
[7]: https://doc.rust-lang.org/std/primitive.i32.html#method.wrapping_add
|
|
[8]: http://en.cppreference.com/w/cpp/language/implicit_conversion
|
|
[9]: https://doc.rust-lang.org/std/primitive.i32.html
|
|
|
|
## Progress
|
|
|
|
- [x] adddf3.c
|
|
- [x] addsf3.c
|
|
- [x] arm/adddf3vfp.S
|
|
- [x] arm/addsf3vfp.S
|
|
- [x] arm/aeabi_dcmp.S
|
|
- [x] arm/aeabi_fcmp.S
|
|
- [x] arm/aeabi_idivmod.S
|
|
- [x] arm/aeabi_ldivmod.S
|
|
- [x] arm/aeabi_memcpy.S
|
|
- [x] arm/aeabi_memmove.S
|
|
- [x] arm/aeabi_memset.S
|
|
- [x] arm/aeabi_uidivmod.S
|
|
- [x] arm/aeabi_uldivmod.S
|
|
- [x] arm/divdf3vfp.S
|
|
- [ ] arm/divmodsi4.S (generic version is done)
|
|
- [x] arm/divsf3vfp.S
|
|
- [ ] arm/divsi3.S (generic version is done)
|
|
- [x] arm/eqdf2vfp.S
|
|
- [x] arm/eqsf2vfp.S
|
|
- [x] arm/extendsfdf2vfp.S
|
|
- [ ] arm/fixdfsivfp.S
|
|
- [ ] arm/fixsfsivfp.S
|
|
- [ ] arm/fixunsdfsivfp.S
|
|
- [ ] arm/fixunssfsivfp.S
|
|
- [ ] arm/floatsidfvfp.S
|
|
- [ ] arm/floatsisfvfp.S
|
|
- [ ] arm/floatunssidfvfp.S
|
|
- [ ] arm/floatunssisfvfp.S
|
|
- [x] arm/gedf2vfp.S
|
|
- [x] arm/gesf2vfp.S
|
|
- [x] arm/gtdf2vfp.S
|
|
- [x] arm/gtsf2vfp.S
|
|
- [x] arm/ledf2vfp.S
|
|
- [x] arm/lesf2vfp.S
|
|
- [x] arm/ltdf2vfp.S
|
|
- [x] arm/ltsf2vfp.S
|
|
- [ ] arm/modsi3.S (generic version is done)
|
|
- [x] arm/muldf3vfp.S
|
|
- [x] arm/mulsf3vfp.S
|
|
- [x] arm/nedf2vfp.S
|
|
- [ ] arm/negdf2vfp.S
|
|
- [ ] arm/negsf2vfp.S
|
|
- [x] arm/nesf2vfp.S
|
|
- [x] arm/softfloat-alias.list
|
|
- [x] arm/subdf3vfp.S
|
|
- [x] arm/subsf3vfp.S
|
|
- [x] arm/truncdfsf2vfp.S
|
|
- [ ] arm/udivmodsi4.S (generic version is done)
|
|
- [ ] arm/udivsi3.S (generic version is done)
|
|
- [ ] arm/umodsi3.S (generic version is done)
|
|
- [ ] arm/unorddf2vfp.S
|
|
- [ ] arm/unordsf2vfp.S
|
|
- [x] ashldi3.c
|
|
- [x] ashrdi3.c
|
|
- [x] comparedf2.c
|
|
- [x] comparesf2.c
|
|
- [x] divdf3.c
|
|
- [x] divdi3.c
|
|
- [x] divmoddi4.c
|
|
- [x] divmodsi4.c
|
|
- [x] divsf3.c
|
|
- [x] divsi3.c
|
|
- [ ] extendhfsf2.c
|
|
- [x] extendsfdf2.c
|
|
- [x] fixdfdi.c
|
|
- [x] fixdfsi.c
|
|
- [x] fixsfdi.c
|
|
- [x] fixsfsi.c
|
|
- [x] fixunsdfdi.c
|
|
- [x] fixunsdfsi.c
|
|
- [x] fixunssfdi.c
|
|
- [x] fixunssfsi.c
|
|
- [x] floatdidf.c
|
|
- [x] floatdisf.c
|
|
- [x] floatsidf.c
|
|
- [x] floatsisf.c
|
|
- [x] floatundidf.c
|
|
- [x] floatundisf.c
|
|
- [x] floatunsidf.c
|
|
- [x] floatunsisf.c
|
|
- [ ] i386/ashldi3.S
|
|
- [ ] i386/ashrdi3.S
|
|
- [x] i386/chkstk.S
|
|
- [x] i386/chkstk2.S
|
|
- [ ] i386/divdi3.S
|
|
- [ ] i386/lshrdi3.S
|
|
- [ ] i386/moddi3.S
|
|
- [ ] i386/muldi3.S
|
|
- [ ] i386/udivdi3.S
|
|
- [ ] i386/umoddi3.S
|
|
- [x] lshrdi3.c
|
|
- [x] moddi3.c
|
|
- [x] modsi3.c
|
|
- [x] muldf3.c
|
|
- [x] muldi3.c
|
|
- [x] mulodi4.c
|
|
- [x] mulosi4.c
|
|
- [x] mulsf3.c
|
|
- [x] powidf2.c
|
|
- [x] powisf2.c
|
|
- [x] subdf3.c
|
|
- [x] subsf3.c
|
|
- [ ] truncdfhf2.c
|
|
- [x] truncdfsf2.c
|
|
- [ ] truncsfhf2.c
|
|
- [x] udivdi3.c
|
|
- [x] udivmoddi4.c
|
|
- [x] udivmodsi4.c
|
|
- [x] udivsi3.c
|
|
- [x] umoddi3.c
|
|
- [x] umodsi3.c
|
|
- [x] x86_64/chkstk.S
|
|
- [x] x86_64/chkstk2.S
|
|
|
|
These builtins are needed to support 128-bit integers, which are in the process of being added to Rust.
|
|
|
|
- [x] ashlti3.c
|
|
- [x] ashrti3.c
|
|
- [x] divti3.c
|
|
- [x] fixdfti.c
|
|
- [x] fixsfti.c
|
|
- [x] fixunsdfti.c
|
|
- [x] fixunssfti.c
|
|
- [x] floattidf.c
|
|
- [x] floattisf.c
|
|
- [x] floatuntidf.c
|
|
- [x] floatuntisf.c
|
|
- [x] lshrti3.c
|
|
- [x] modti3.c
|
|
- [x] muloti4.c
|
|
- [x] multi3.c
|
|
- [x] udivmodti4.c
|
|
- [x] udivti3.c
|
|
- [x] umodti3.c
|
|
|
|
## Unimplemented functions
|
|
|
|
These builtins involve floating-point types ("`f128`", "`f80`" and complex numbers) that are not supported by Rust.
|
|
|
|
- ~~addtf3.c~~
|
|
- ~~comparetf2.c~~
|
|
- ~~divdc3.c~~
|
|
- ~~divsc3.c~~
|
|
- ~~divtc3.c~~
|
|
- ~~divtf3.c~~
|
|
- ~~divxc3.c~~
|
|
- ~~extenddftf2.c~~
|
|
- ~~extendsftf2.c~~
|
|
- ~~fixtfdi.c~~
|
|
- ~~fixtfsi.c~~
|
|
- ~~fixtfti.c~~
|
|
- ~~fixunstfdi.c~~
|
|
- ~~fixunstfsi.c~~
|
|
- ~~fixunstfti.c~~
|
|
- ~~fixunsxfdi.c~~
|
|
- ~~fixunsxfsi.c~~
|
|
- ~~fixunsxfti.c~~
|
|
- ~~fixxfdi.c~~
|
|
- ~~fixxfti.c~~
|
|
- ~~floatditf.c~~
|
|
- ~~floatdixf.c~~
|
|
- ~~floatsitf.c~~
|
|
- ~~floattixf.c~~
|
|
- ~~floatunditf.c~~
|
|
- ~~floatundixf.c~~
|
|
- ~~floatunsitf.c~~
|
|
- ~~floatuntixf.c~~
|
|
- ~~i386/floatdixf.S~~
|
|
- ~~i386/floatundixf.S~~
|
|
- ~~muldc3.c~~
|
|
- ~~mulsc3.c~~
|
|
- ~~multc3.c~~
|
|
- ~~multf3.c~~
|
|
- ~~mulxc3.c~~
|
|
- ~~powitf2.c~~
|
|
- ~~powixf2.c~~
|
|
- ~~ppc/divtc3.c~~
|
|
- ~~ppc/fixtfdi.c~~
|
|
- ~~ppc/fixunstfdi.c~~
|
|
- ~~ppc/floatditf.c~~
|
|
- ~~ppc/floatunditf.c~~
|
|
- ~~ppc/gcc_qadd.c~~
|
|
- ~~ppc/gcc_qdiv.c~~
|
|
- ~~ppc/gcc_qmul.c~~
|
|
- ~~ppc/gcc_qsub.c~~
|
|
- ~~ppc/multc3.c~~
|
|
- ~~subtf3.c~~
|
|
- ~~trunctfdf2.c~~
|
|
- ~~trunctfsf2.c~~
|
|
- ~~x86_64/floatdixf.c~~
|
|
- ~~x86_64/floatundixf.S~~
|
|
|
|
These builtins are never called by LLVM.
|
|
|
|
- ~~absvdi2.c~~
|
|
- ~~absvsi2.c~~
|
|
- ~~absvti2.c~~
|
|
- ~~addvdi3.c~~
|
|
- ~~addvsi3.c~~
|
|
- ~~addvti3.c~~
|
|
- ~~arm/aeabi_cdcmp.S~~
|
|
- ~~arm/aeabi_cdcmpeq_check_nan.c~~
|
|
- ~~arm/aeabi_cfcmp.S~~
|
|
- ~~arm/aeabi_cfcmpeq_check_nan.c~~
|
|
- ~~arm/aeabi_div0.c~~
|
|
- ~~arm/aeabi_drsub.c~~
|
|
- ~~arm/aeabi_frsub.c~~
|
|
- ~~arm/aeabi_memcmp.S~~
|
|
- ~~arm/bswapdi2.S~~
|
|
- ~~arm/bswapsi2.S~~
|
|
- ~~arm/clzdi2.S~~
|
|
- ~~arm/clzsi2.S~~
|
|
- ~~arm/comparesf2.S~~
|
|
- ~~arm/restore_vfp_d8_d15_regs.S~~
|
|
- ~~arm/save_vfp_d8_d15_regs.S~~
|
|
- ~~arm/switch16.S~~
|
|
- ~~arm/switch32.S~~
|
|
- ~~arm/switch8.S~~
|
|
- ~~arm/switchu8.S~~
|
|
- ~~clzdi2.c~~
|
|
- ~~clzsi2.c~~
|
|
- ~~clzti2.c~~
|
|
- ~~cmpdi2.c~~
|
|
- ~~cmpti2.c~~
|
|
- ~~ctzdi2.c~~
|
|
- ~~ctzsi2.c~~
|
|
- ~~ctzti2.c~~
|
|
- ~~ffsdi2.c~~ - this is [called by gcc][jemalloc-fail] though!
|
|
- ~~ffsti2.c~~
|
|
- ~~mulvdi3.c~~
|
|
- ~~mulvsi3.c~~
|
|
- ~~mulvti3.c~~
|
|
- ~~negdf2.c~~
|
|
- ~~negdi2.c~~
|
|
- ~~negsf2.c~~
|
|
- ~~negti2.c~~
|
|
- ~~negvdi2.c~~
|
|
- ~~negvsi2.c~~
|
|
- ~~negvti2.c~~
|
|
- ~~paritydi2.c~~
|
|
- ~~paritysi2.c~~
|
|
- ~~parityti2.c~~
|
|
- ~~popcountdi2.c~~
|
|
- ~~popcountsi2.c~~
|
|
- ~~popcountti2.c~~
|
|
- ~~ppc/restFP.S~~
|
|
- ~~ppc/saveFP.S~~
|
|
- ~~subvdi3.c~~
|
|
- ~~subvsi3.c~~
|
|
- ~~subvti3.c~~
|
|
- ~~ucmpdi2.c~~
|
|
- ~~ucmpti2.c~~
|
|
- ~~udivmodti4.c~~
|
|
|
|
[jemalloc-fail]: https://travis-ci.org/rust-lang/rust/jobs/249772758
|
|
|
|
Rust only exposes atomic types on platforms that support them, and therefore does not need to fall back to software implementations.
|
|
|
|
- ~~arm/sync_fetch_and_add_4.S~~
|
|
- ~~arm/sync_fetch_and_add_8.S~~
|
|
- ~~arm/sync_fetch_and_and_4.S~~
|
|
- ~~arm/sync_fetch_and_and_8.S~~
|
|
- ~~arm/sync_fetch_and_max_4.S~~
|
|
- ~~arm/sync_fetch_and_max_8.S~~
|
|
- ~~arm/sync_fetch_and_min_4.S~~
|
|
- ~~arm/sync_fetch_and_min_8.S~~
|
|
- ~~arm/sync_fetch_and_nand_4.S~~
|
|
- ~~arm/sync_fetch_and_nand_8.S~~
|
|
- ~~arm/sync_fetch_and_or_4.S~~
|
|
- ~~arm/sync_fetch_and_or_8.S~~
|
|
- ~~arm/sync_fetch_and_sub_4.S~~
|
|
- ~~arm/sync_fetch_and_sub_8.S~~
|
|
- ~~arm/sync_fetch_and_umax_4.S~~
|
|
- ~~arm/sync_fetch_and_umax_8.S~~
|
|
- ~~arm/sync_fetch_and_umin_4.S~~
|
|
- ~~arm/sync_fetch_and_umin_8.S~~
|
|
- ~~arm/sync_fetch_and_xor_4.S~~
|
|
- ~~arm/sync_fetch_and_xor_8.S~~
|
|
- ~~arm/sync_synchronize.S~~
|
|
- ~~atomic.c~~
|
|
- ~~atomic_flag_clear.c~~
|
|
- ~~atomic_flag_clear_explicit.c~~
|
|
- ~~atomic_flag_test_and_set.c~~
|
|
- ~~atomic_flag_test_and_set_explicit.c~~
|
|
- ~~atomic_signal_fence.c~~
|
|
- ~~atomic_thread_fence.c~~
|
|
|
|
Miscellaneous functionality that is not used by Rust.
|
|
|
|
- ~~apple_versioning.c~~
|
|
- ~~clear_cache.c~~
|
|
- ~~emutls.c~~
|
|
- ~~enable_execute_stack.c~~
|
|
- ~~eprintf.c~~
|
|
- ~~gcc_personality_v0.c~~
|
|
- ~~trampoline_setup.c~~
|
|
|
|
Floating-point implementations of builtins that are only called from soft-float code. It would be better to simply use the generic soft-float versions in this case.
|
|
|
|
- ~~i386/floatdidf.S~~
|
|
- ~~i386/floatdisf.S~~
|
|
- ~~i386/floatundidf.S~~
|
|
- ~~i386/floatundisf.S~~
|
|
- ~~x86_64/floatundidf.S~~
|
|
- ~~x86_64/floatundisf.S~~
|
|
- ~~x86_64/floatdidf.c~~
|
|
- ~~x86_64/floatdisf.c~~
|
|
|
|
## License
|
|
|
|
The compiler-builtins crate is dual licensed under both the University of
|
|
Illinois "BSD-Like" license and the MIT license. As a user of this code you may
|
|
choose to use it under either license. As a contributor, you agree to allow
|
|
your code to be used under both.
|
|
|
|
Full text of the relevant licenses is in LICENSE.TXT.
|