Merge commit '08a6d6e16b5efe217123e780398969946266268f' into sync-cg_gcc-2023-03-04

1 files changed, 112 insertions, 0 deletions

diff --git a/compiler/rustc_codegen_gcc/src/attributes.rs b/compiler/rustc_codegen_gcc/src/attributes.rs
new file mode 100644
index 00000000000..243a1a36dd0
--- /dev/null
+++ b/compiler/rustc_codegen_gcc/src/attributes.rs
@@ -0,0 +1,112 @@
+#[cfg(feature="master")]
+use gccjit::FnAttribute;
+use gccjit::Function;
+use rustc_attr::InstructionSetAttr;
+use rustc_codegen_ssa::target_features::tied_target_features;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_middle::ty;
+use rustc_session::Session;
+use rustc_span::symbol::sym;
+use smallvec::{smallvec, SmallVec};
+
+use crate::context::CodegenCx;
+
+// Given a map from target_features to whether they are enabled or disabled,
+// ensure only valid combinations are allowed.
+pub fn check_tied_features(sess: &Session, features: &FxHashMap<&str, bool>) -> Option<&'static [&'static str]> {
+    for tied in tied_target_features(sess) {
+        // Tied features must be set to the same value, or not set at all
+        let mut tied_iter = tied.iter();
+        let enabled = features.get(tied_iter.next().unwrap());
+        if tied_iter.any(|feature| enabled != features.get(feature)) {
+            return Some(tied);
+        }
+    }
+    None
+}
+
+// TODO(antoyo): maybe move to a new module gcc_util.
+// To find a list of GCC's names, check https://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
+fn to_gcc_features<'a>(sess: &Session, s: &'a str) -> SmallVec<[&'a str; 2]> {
+    let arch = if sess.target.arch == "x86_64" { "x86" } else { &*sess.target.arch };
+    match (arch, s) {
+        ("x86", "sse4.2") => smallvec!["sse4.2", "crc32"],
+        ("x86", "pclmulqdq") => smallvec!["pclmul"],
+        ("x86", "rdrand") => smallvec!["rdrnd"],
+        ("x86", "bmi1") => smallvec!["bmi"],
+        ("x86", "cmpxchg16b") => smallvec!["cx16"],
+        ("x86", "avx512vaes") => smallvec!["vaes"],
+        ("x86", "avx512gfni") => smallvec!["gfni"],
+        ("x86", "avx512vpclmulqdq") => smallvec!["vpclmulqdq"],
+        // NOTE: seems like GCC requires 'avx512bw' for 'avx512vbmi2'.
+        ("x86", "avx512vbmi2") => smallvec!["avx512vbmi2", "avx512bw"],
+        // NOTE: seems like GCC requires 'avx512bw' for 'avx512bitalg'.
+        ("x86", "avx512bitalg") => smallvec!["avx512bitalg", "avx512bw"],
+        ("aarch64", "rcpc2") => smallvec!["rcpc-immo"],
+        ("aarch64", "dpb") => smallvec!["ccpp"],
+        ("aarch64", "dpb2") => smallvec!["ccdp"],
+        ("aarch64", "frintts") => smallvec!["fptoint"],
+        ("aarch64", "fcma") => smallvec!["complxnum"],
+        ("aarch64", "pmuv3") => smallvec!["perfmon"],
+        ("aarch64", "paca") => smallvec!["pauth"],
+        ("aarch64", "pacg") => smallvec!["pauth"],
+        // Rust ties fp and neon together. In LLVM neon implicitly enables fp,
+        // but we manually enable neon when a feature only implicitly enables fp
+        ("aarch64", "f32mm") => smallvec!["f32mm", "neon"],
+        ("aarch64", "f64mm") => smallvec!["f64mm", "neon"],
+        ("aarch64", "fhm") => smallvec!["fp16fml", "neon"],
+        ("aarch64", "fp16") => smallvec!["fullfp16", "neon"],
+        ("aarch64", "jsconv") => smallvec!["jsconv", "neon"],
+        ("aarch64", "sve") => smallvec!["sve", "neon"],
+        ("aarch64", "sve2") => smallvec!["sve2", "neon"],
+        ("aarch64", "sve2-aes") => smallvec!["sve2-aes", "neon"],
+        ("aarch64", "sve2-sm4") => smallvec!["sve2-sm4", "neon"],
+        ("aarch64", "sve2-sha3") => smallvec!["sve2-sha3", "neon"],
+        ("aarch64", "sve2-bitperm") => smallvec!["sve2-bitperm", "neon"],
+        (_, s) => smallvec![s],
+    }
+}
+
+/// Composite function which sets GCC attributes for function depending on its AST (`#[attribute]`)
+/// attributes.
+pub fn from_fn_attrs<'gcc, 'tcx>(
+    cx: &CodegenCx<'gcc, 'tcx>,
+    #[cfg_attr(not(feature="master"), allow(unused_variables))]
+    func: Function<'gcc>,
+    instance: ty::Instance<'tcx>,
+) {
+    let codegen_fn_attrs = cx.tcx.codegen_fn_attrs(instance.def_id());
+
+    let function_features =
+        codegen_fn_attrs.target_features.iter().map(|features| features.as_str()).collect::<Vec<&str>>();
+
+    if let Some(features) = check_tied_features(cx.tcx.sess, &function_features.iter().map(|features| (*features, true)).collect()) {
+        let span = cx.tcx
+            .get_attr(instance.def_id(), sym::target_feature)
+            .map_or_else(|| cx.tcx.def_span(instance.def_id()), |a| a.span);
+        let msg = format!("the target features {} must all be either enabled or disabled together", features.join(", "));
+        let mut err = cx.tcx.sess.struct_span_err(span, &msg);
+        err.help("add the missing features in a `target_feature` attribute");
+        err.emit();
+        return;
+    }
+
+    let mut function_features = function_features
+        .iter()
+        .flat_map(|feat| to_gcc_features(cx.tcx.sess, feat).into_iter())
+        .chain(codegen_fn_attrs.instruction_set.iter().map(|x| match x {
+            InstructionSetAttr::ArmA32 => "-thumb-mode", // TODO(antoyo): support removing feature.
+            InstructionSetAttr::ArmT32 => "thumb-mode",
+        }))
+        .collect::<Vec<_>>();
+
+    // TODO(antoyo): check if we really need global backend features. (Maybe they could be applied
+    // globally?)
+    let mut global_features = cx.tcx.global_backend_features(()).iter().map(|s| s.as_str());
+    function_features.extend(&mut global_features);
+    let target_features = function_features.join(",");
+    if !target_features.is_empty() {
+        #[cfg(feature="master")]
+        func.add_attribute(FnAttribute::Target(&target_features));
+    }
+}