add rustc_codegen_ssa support for csky and correct some code

compiler/rustc_codegen_ssa/src/back/metadata.rs

@@ -209,6 +209,7 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
         "hexagon" => Architecture::Hexagon,
         "bpf" => Architecture::Bpf,
         "loongarch64" => Architecture::LoongArch64,
+        "csky" => Architecture::Csky,
         // Unsupported architecture.
         _ => return None,
     };
@@ -307,6 +308,13 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
             // the appropriate EF_AVR_ARCH flag.
             ef_avr_arch(&sess.target.options.cpu)
         }
+        Architecture::Csky => {
+            let e_flags = match sess.target.options.abi.as_ref() {
+                "abiv2" => elf::EF_CSKY_ABIV2,
+                _ => elf::EF_CSKY_ABIV1,
+            };
+            e_flags
+        }
         _ => 0,
     };
     // adapted from LLVM's `MCELFObjectTargetWriter::getOSABI`

compiler/rustc_codegen_ssa/src/target_features.rs

@@ -296,6 +296,16 @@ const WASM_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
 
 const BPF_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[("alu32", Some(sym::bpf_target_feature))];
 
+const CSKY_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
+    ("hard-float", Some(sym::csky_target_feature)),
+    ("hard-float-abi", Some(sym::csky_target_feature)),
+    ("fpuv2_sf", Some(sym::csky_target_feature)),
+    ("fpuv2_df", Some(sym::csky_target_feature)),
+    ("fpuv3_sf", Some(sym::csky_target_feature)),
+    ("fpuv3_df", Some(sym::csky_target_feature)),
+    ("vdspv2", Some(sym::csky_target_feature)),
+    ("dspv2", Some(sym::csky_target_feature)),
+];
 /// When rustdoc is running, provide a list of all known features so that all their respective
 /// primitives may be documented.
 ///
@@ -311,6 +321,7 @@ pub fn all_known_features() -> impl Iterator<Item = (&'static str, Option<Symbol
         .chain(RISCV_ALLOWED_FEATURES.iter())
         .chain(WASM_ALLOWED_FEATURES.iter())
         .chain(BPF_ALLOWED_FEATURES.iter())
+        .chain(CSKY_ALLOWED_FEATURES)
         .cloned()
 }
 
@@ -325,6 +336,7 @@ pub fn supported_target_features(sess: &Session) -> &'static [(&'static str, Opt
         "riscv32" | "riscv64" => RISCV_ALLOWED_FEATURES,
         "wasm32" | "wasm64" => WASM_ALLOWED_FEATURES,
         "bpf" => BPF_ALLOWED_FEATURES,
+        "csky" => CSKY_ALLOWED_FEATURES,
         _ => &[],
     }
 }
@@ -396,6 +408,7 @@ pub fn from_target_feature(
                 Some(sym::ermsb_target_feature) => rust_features.ermsb_target_feature,
                 Some(sym::bpf_target_feature) => rust_features.bpf_target_feature,
                 Some(sym::aarch64_ver_target_feature) => rust_features.aarch64_ver_target_feature,
+                Some(sym::csky_target_feature) => rust_features.csky_target_feature,
                 Some(name) => bug!("unknown target feature gate {}", name),
                 None => true,
             };

compiler/rustc_feature/src/active.rs

@@ -282,6 +282,7 @@ declare_features! (
     (active, arm_target_feature, "1.27.0", Some(44839), None),
     (active, avx512_target_feature, "1.27.0", Some(44839), None),
     (active, bpf_target_feature, "1.54.0", Some(44839), None),
+    (active, csky_target_feature, "1.72.0", Some(44839), None),
     (active, ermsb_target_feature, "1.49.0", Some(44839), None),
     (active, hexagon_target_feature, "1.27.0", Some(44839), None),
     (active, mips_target_feature, "1.27.0", Some(44839), None),

compiler/rustc_span/src/symbol.rs

@@ -574,6 +574,7 @@ symbols! {
         crate_type,
         crate_visibility_modifier,
         crt_dash_static: "crt-static",
+        csky_target_feature,
         cstring_type,
         ctlz,
         ctlz_nonzero,

compiler/rustc_target/src/spec/csky_unknown_linux_gnuabiv2.rs

@@ -6,7 +6,7 @@ use crate::spec::{Target, TargetOptions};
 pub fn target() -> Target {
     Target {
         //https://github.com/llvm/llvm-project/blob/8b76aea8d8b1b71f6220bc2845abc749f18a19b7/clang/lib/Basic/Targets/CSKY.h
-        llvm_target: "csky-unknown-linux".into(),
+        llvm_target: "csky-unknown-linux-gnuabiv2".into(),
         pointer_width: 32,
         data_layout: "e-m:e-S32-p:32:32-i32:32:32-i64:32:32-f32:32:32-f64:32:32-v64:32:32-v128:32:32-a:0:32-Fi32-n32".into(),
         arch: "csky".into(),

src/doc/rustc/src/platform-support/csky-unknown-linux-gnuabiv2.md

@@ -2,7 +2,7 @@
 
 **Tier: 3**
 
-This target supports [C-SKY](https://github.com/c-sky) v2 CPUs with `glibc`.
+This target supports [C-SKY](https://github.com/c-sky) CPUs with `abi` v2 and `glibc`.
 
 https://c-sky.github.io/
 ## Target maintainers

tests/ui/check-cfg/compact-values.stderr

@@ -4,7 +4,7 @@ warning: unexpected `cfg` condition value
 LL | #[cfg(target(os = "linux", arch = "X"))]
    |                            ^^^^^^^^^^
    |
-   = note: expected values for `target_arch` are: `aarch64`, `arm`, `avr`, `bpf`, `hexagon`, `loongarch64`, `m68k`, `mips`, `mips32r6`, `mips64`, `mips64r6`, `msp430`, `nvptx64`, `powerpc`, `powerpc64`, `riscv32`, `riscv64`, `s390x`, `sparc`, `sparc64`, `wasm32`, `wasm64`, `x86`, `x86_64`
+   = note: expected values for `target_arch` are: `aarch64`, `arm`, `avr`, `bpf`, `csky`, `hexagon`, `loongarch64`, `m68k`, `mips`, `mips32r6`, `mips64`, `mips64r6`, `msp430`, `nvptx64`, `powerpc`, `powerpc64`, `riscv32`, `riscv64`, `s390x`, `sparc`, `sparc64`, `wasm32`, `wasm64`, `x86`, `x86_64`
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: 1 warning emitted