diff options
Diffstat (limited to '')
-rw-r--r-- | src/tools/rustfmt/tests/target/cfg_if/detect/os/linux/arm.rs | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/src/tools/rustfmt/tests/target/cfg_if/detect/os/linux/arm.rs b/src/tools/rustfmt/tests/target/cfg_if/detect/os/linux/arm.rs new file mode 100644 index 000000000..9c89500cc --- /dev/null +++ b/src/tools/rustfmt/tests/target/cfg_if/detect/os/linux/arm.rs @@ -0,0 +1,52 @@ +//! Run-time feature detection for ARM on Linux. + +use super::{auxvec, cpuinfo}; +use crate::detect::{bit, cache, Feature}; + +/// Performs run-time feature detection. +#[inline] +pub fn check_for(x: Feature) -> bool { + cache::test(x as u32, detect_features) +} + +/// Try to read the features from the auxiliary vector, and if that fails, try +/// to read them from /proc/cpuinfo. +fn detect_features() -> cache::Initializer { + let mut value = cache::Initializer::default(); + let enable_feature = |value: &mut cache::Initializer, f, enable| { + if enable { + value.set(f as u32); + } + }; + + // The values are part of the platform-specific [asm/hwcap.h][hwcap] + // + // [hwcap]: https://github.com/torvalds/linux/blob/master/arch/arm64/include/uapi/asm/hwcap.h + if let Ok(auxv) = auxvec::auxv() { + enable_feature(&mut value, Feature::neon, bit::test(auxv.hwcap, 12)); + enable_feature(&mut value, Feature::pmull, bit::test(auxv.hwcap2, 1)); + return value; + } + + if let Ok(c) = cpuinfo::CpuInfo::new() { + enable_feature( + &mut value, + Feature::neon, + c.field("Features").has("neon") && !has_broken_neon(&c), + ); + enable_feature(&mut value, Feature::pmull, c.field("Features").has("pmull")); + return value; + } + value +} + +/// Is the CPU known to have a broken NEON unit? +/// +/// See https://crbug.com/341598. +fn has_broken_neon(cpuinfo: &cpuinfo::CpuInfo) -> bool { + cpuinfo.field("CPU implementer") == "0x51" + && cpuinfo.field("CPU architecture") == "7" + && cpuinfo.field("CPU variant") == "0x1" + && cpuinfo.field("CPU part") == "0x04d" + && cpuinfo.field("CPU revision") == "0" +} |