From 6ceeb0849e181999fc6ecc2cb9dcfdc65b5effd3 Mon Sep 17 00:00:00 2001 From: Trevor Gross Date: Thu, 24 Apr 2025 22:11:23 +0000 Subject: Implement the internal feature `cfg_target_has_reliable_f16_f128` Support for `f16` and `f128` is varied across targets, backends, and backend versions. Eventually we would like to reach a point where all backends support these approximately equally, but until then we have to work around some of these nuances of support being observable. Introduce the `cfg_target_has_reliable_f16_f128` internal feature, which provides the following new configuration gates: * `cfg(target_has_reliable_f16)` * `cfg(target_has_reliable_f16_math)` * `cfg(target_has_reliable_f128)` * `cfg(target_has_reliable_f128_math)` `reliable_f16` and `reliable_f128` indicate that basic arithmetic for the type works correctly. The `_math` versions indicate that anything relying on `libm` works correctly, since sometimes this hits a separate class of codegen bugs. These options match configuration set by the build script at [1]. The logic for LLVM support is duplicated as-is from the same script. There are a few possible updates that will come as a follow up. The config introduced here is not planned to ever become stable, it is only intended to replace the build scripts for `std` tests and `compiler-builtins` that don't have any way to configure based on the codegen backend. MCP: https://github.com/rust-lang/compiler-team/issues/866 Closes: https://github.com/rust-lang/compiler-team/issues/866 [1]: https://github.com/rust-lang/rust/blob/555e1d0386f024a8359645c3217f4b3eae9be042/library/std/build.rs#L84-L186 --- compiler/rustc_codegen_cranelift/src/lib.rs | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'compiler/rustc_codegen_cranelift/src') diff --git a/compiler/rustc_codegen_cranelift/src/lib.rs b/compiler/rustc_codegen_cranelift/src/lib.rs index 9d9e790289c..ab09a6f8b38 100644 --- a/compiler/rustc_codegen_cranelift/src/lib.rs +++ b/compiler/rustc_codegen_cranelift/src/lib.rs @@ -41,8 +41,8 @@ use std::sync::Arc; use cranelift_codegen::isa::TargetIsa; use cranelift_codegen::settings::{self, Configurable}; -use rustc_codegen_ssa::CodegenResults; use rustc_codegen_ssa::traits::CodegenBackend; +use rustc_codegen_ssa::{CodegenResults, TargetConfig}; use rustc_metadata::EncodedMetadata; use rustc_middle::dep_graph::{WorkProduct, WorkProductId}; use rustc_session::Session; @@ -178,7 +178,7 @@ impl CodegenBackend for CraneliftCodegenBackend { } } - fn target_features_cfg(&self, sess: &Session) -> (Vec, Vec) { + fn target_config(&self, sess: &Session) -> TargetConfig { // FIXME return the actually used target features. this is necessary for #[cfg(target_feature)] let target_features = if sess.target.arch == "x86_64" && sess.target.os != "none" { // x86_64 mandates SSE2 support and rustc requires the x87 feature to be enabled @@ -197,7 +197,16 @@ impl CodegenBackend for CraneliftCodegenBackend { }; // FIXME do `unstable_target_features` properly let unstable_target_features = target_features.clone(); - (target_features, unstable_target_features) + + TargetConfig { + target_features, + unstable_target_features, + // Cranelift does not yet support f16 or f128 + has_reliable_f16: false, + has_reliable_f16_math: false, + has_reliable_f128: false, + has_reliable_f128_math: false, + } } fn print_version(&self) { -- cgit 1.4.1-3-g733a5